This page has only limited features, please log in for full access.

Unclaimed
Robert Trigiano
Department of Entomology and Plant Pathology, Institute of Agriculture, University of Tennessee, Knoxville, TN 37996-4560, USA

Honors and Awards

The user has no records in this section


Career Timeline

The user has no records in this section.


Short Biography

The user biography is not available.
Following
Followers
Co Authors
The list of users this user is following is empty.
Following: 0 users

Feed

Journal article
Published: 30 July 2021 in Plants
Reads 0
Downloads 0

Helianthus verticillatus Small, the whorled sunflower, is a perennial species only found at a few sites in the southeastern United States and was declared federally (USA) endangered in 2014. The species spreads locally via rhizomes and can produce copious seeds when sexually compatible genotypes are present. Vegetative propagation of the species via cuttings and the optimum conditions for seed germination have not been determined. To investigate asexual propagation via cuttings, stem sections were harvested in late May, June, and July in Knoxville, Tennessee (USA) and trimmed to a minimum of two nodes. The base of the cuttings was treated with either auxin or water, and grown in a Promix BX potting medium with intermittent mist and 50% shade for one month. Seeds were harvested from a population of multiple genotypes in Maryville, Tennessee and used to determine viability and the range of temperatures suitable for germination. A clonal population was developed and used for three years to assess sexual compatibility at three locations in Knoxville, Tennessee. Ninety-five percent of the cuttings from May rooted in two-to-three weeks and formed more than 20 adventitious roots per cutting with auxin and 18 with water treatments. The ability of cuttings to root decreased in June to about 20%, and none rooted in July with either water or auxin pretreatments. Pre-germination tetrazolium tests indicated that about 91% of seeds (achenes) were viable. Subsequent germination tests revealed high germination at varying temperatures (96 to 99% of seeds (achenes) germinated at 22/11, 27/15, and 29/19 °C), whereas germination was significantly inhibited by 33/24 °C. Fifty percent of the seeds germinated at 22/11 °C in 7.5 days, whereas only 2.0 to 2.5 days were required for 50% germination at 27/15, 29/19, and 33/24 °C. Seeds were not produced at any of the clonal planting locations during the three years. Vegetative propagation via rooted cuttings was successful in the mid-spring, seed germination was possible over a wide range of temperatures, and self-incompatibility was evident in this species. The results of this study will permit fast and efficient propagation of multiple and selected genotypes for conservation, commerce, and breeding of elite cultivars with disease resistance or other desirable attributes.

ACS Style

Robert Trigiano; Sarah Boggess; Christopher Wyman; Denita Hadziabdic; Sandra Wilson. Propagation Methods for the Conservation and Preservation of the Endangered Whorled Sunflower (Helianthus verticillatus). Plants 2021, 10, 1565 .

AMA Style

Robert Trigiano, Sarah Boggess, Christopher Wyman, Denita Hadziabdic, Sandra Wilson. Propagation Methods for the Conservation and Preservation of the Endangered Whorled Sunflower (Helianthus verticillatus). Plants. 2021; 10 (8):1565.

Chicago/Turabian Style

Robert Trigiano; Sarah Boggess; Christopher Wyman; Denita Hadziabdic; Sandra Wilson. 2021. "Propagation Methods for the Conservation and Preservation of the Endangered Whorled Sunflower (Helianthus verticillatus)." Plants 10, no. 8: 1565.

Research article
Published: 23 June 2021 in Mycologia
Reads 0
Downloads 0

In 1911 and 1917, the first commercial plantings of African oil palm (Elaeis guineensis Jacq.) were made in Indonesia and Malaysia in Southeast Asia. In less than 15 years, basal stem rot (BSR) was reported in Malaysia. It took nearly another seven decades to identify the main causal agent of BSR as the fungus, Ganoderma boninense. Since then, research efforts have focused on understanding G. boninense disease epidemiology, biology, and etiology, but limited progress was made to characterize pathogen genetic diversity, spatial structure, pathogenicity, and virulence. This study describes pathogen variability, gene flow, population differentiation, and genetic structure of G. boninense in Sarawak (Malaysia), Peninsular Malaysia, and Sumatra (Indonesia) inferred by 16 highly polymorphic cDNA-SSR (simple sequence repeat) markers. Marker-inferred genotypic diversity indicated a high level of pathogen variability among individuals within a population and among different populations. This genetic variability is clearly the result of outcrossing between basidiospores to produce recombinant genotypes. Although our results indicated high gene flow among the populations, there was no significant genetic differentiation among G. boninense populations on a regional scale. It suggested that G. boninense genetic makeup is similar across a wide region. Furthermore, our results revealed the existence of three admixed genetic clusters of G. boninense associated with BSR-diseased oil palms sampled throughout Sarawak, Peninsular Malaysia, and Sumatra. We postulate that the population structure is likely a reflection of the high genetic variability of G. boninense populations. This, in turn, could be explained by highly successful outcrossing between basidiospores of G. boninense from Southeast Asia and introduced genetic sources from various regions of the world, as well as regional adaptation of various pathogen genotypes to different palm hosts. Pathogen variability and population structure could be employed to deduce the epidemiology of G. boninense, as well as the implications of plantation cultural practices on BSR disease control in different regions.

ACS Style

W. C. Wong; H. J. Tung; M. Nurul Fadhilah; F. Midot; S. Y. L. Lau; L. Melling; S. Astari; Đ. Hadziabdic; R. N. Trigiano; K. J. Goh; Y. K. Goh. Genetic diversity and gene flow amongst admixed populations of Ganoderma boninense, causal agent of basal stem rot in African oil palm (Elaeis guineensis Jacq.) in Sarawak (Malaysia), Peninsular Malaysia, and Sumatra (Indonesia). Mycologia 2021, 1 -16.

AMA Style

W. C. Wong, H. J. Tung, M. Nurul Fadhilah, F. Midot, S. Y. L. Lau, L. Melling, S. Astari, Đ. Hadziabdic, R. N. Trigiano, K. J. Goh, Y. K. Goh. Genetic diversity and gene flow amongst admixed populations of Ganoderma boninense, causal agent of basal stem rot in African oil palm (Elaeis guineensis Jacq.) in Sarawak (Malaysia), Peninsular Malaysia, and Sumatra (Indonesia). Mycologia. 2021; ():1-16.

Chicago/Turabian Style

W. C. Wong; H. J. Tung; M. Nurul Fadhilah; F. Midot; S. Y. L. Lau; L. Melling; S. Astari; Đ. Hadziabdic; R. N. Trigiano; K. J. Goh; Y. K. Goh. 2021. "Genetic diversity and gene flow amongst admixed populations of Ganoderma boninense, causal agent of basal stem rot in African oil palm (Elaeis guineensis Jacq.) in Sarawak (Malaysia), Peninsular Malaysia, and Sumatra (Indonesia)." Mycologia , no. : 1-16.

Journal article
Published: 07 June 2021 in Life
Reads 0
Downloads 0

Pyrus calleryana Decne. (Callery pear) includes cultivars that in the United States are popular ornamentals in commercial and residential landscapes. Last few decades, this species has increasingly naturalized across portions of the eastern and southern US. However, the mechanisms behind this plant’s spread are not well understood. The genetic relationship of present-day P.calleryana trees with their Asian P. calleryana forebears (native trees from China, Japan, and Korea) and the original specimens of US cultivars are unknown. We developed and used 18 microsatellite markers to analyze 147 Pyrus source samples and to articulate the status of genetic diversity within Asian P. calleryana and US cultivars. We hypothesized that Asian P. calleryana specimens and US cultivars would be genetically diverse and would show genetic relatedness. Our data revealed high genetic diversity, high gene flow, and presence of population structure in P. calleryana, potentially relating to the highly invasive capability of this species. Strong evidence for genetic relatedness between Asian P. calleryana specimens and US cultivars was also demonstrated. Our data suggest the source for P. calleryana that have become naturalized in US was China. These results will help understand the genetic complexity of invasive P. calleryana when developing management for escaped populations: In follow-up studies, we use the gSSRs developed here to analyze P. calleryana escape populations from across US.

ACS Style

Shiwani Sapkota; Sarah Boggess; Robert Trigiano; William Klingeman; Denita Hadziabdic; David Coyle; Bode Olukolu; Ryan Kuster; Marcin Nowicki. Microsatellite Loci Reveal Genetic Diversity of Asian Callery Pear (Pyrus calleryana) in the Species Native Range and in the North American Cultivars. Life 2021, 11, 531 .

AMA Style

Shiwani Sapkota, Sarah Boggess, Robert Trigiano, William Klingeman, Denita Hadziabdic, David Coyle, Bode Olukolu, Ryan Kuster, Marcin Nowicki. Microsatellite Loci Reveal Genetic Diversity of Asian Callery Pear (Pyrus calleryana) in the Species Native Range and in the North American Cultivars. Life. 2021; 11 (6):531.

Chicago/Turabian Style

Shiwani Sapkota; Sarah Boggess; Robert Trigiano; William Klingeman; Denita Hadziabdic; David Coyle; Bode Olukolu; Ryan Kuster; Marcin Nowicki. 2021. "Microsatellite Loci Reveal Genetic Diversity of Asian Callery Pear (Pyrus calleryana) in the Species Native Range and in the North American Cultivars." Life 11, no. 6: 531.

Journal article
Published: 05 March 2021 in Plants
Reads 0
Downloads 0

The Viburnum genus is of particular interest to horticulturalists, phylogeneticists, and biogeographers. Despite its popularity, there are few existing molecular markers to investigate genetic diversity in this large genus, which includes over 160 species. There are also few polymorphic molecular tools that can delineate closely related species within the genus. Viburnum farreri, a member of the Solenotinus subclade and one of the centers of diversity for Viburnum, was selected for DNA sequencing and development of genomic simple sequence repeats (gSSRs). In this study, 15 polymorphic gSSRs were developed and characterized for a collection of 19 V. farreri samples. Number of alleles per locus ranged from two- to- eight and nine loci had four or more alleles. Observed heterozygosity ranged from 0 to 0.84 and expected heterozygosity ranged from 0.10 to 0.80 for the 15 loci. Shannon diversity index values across these loci ranged from 0.21 to 1.62. The markers developed in this study add to the existing molecular toolkit for the genus and will be used in future studies investigating cross-transferability, genetic variation, and species and cultivar delimitation in the Viburnum genus and closely allied genera in the Adoxaceae and Caprifoliaceae.

ACS Style

Trinity Hamm; Marcin Nowicki; Sarah Boggess; William Klingeman; Denita Hadziabdic; Matthew Huff; Margaret Staton; Robert Trigiano. Development and Characterization of 15 Novel Genomic SSRs for Viburnum farreri. Plants 2021, 10, 487 .

AMA Style

Trinity Hamm, Marcin Nowicki, Sarah Boggess, William Klingeman, Denita Hadziabdic, Matthew Huff, Margaret Staton, Robert Trigiano. Development and Characterization of 15 Novel Genomic SSRs for Viburnum farreri. Plants. 2021; 10 (3):487.

Chicago/Turabian Style

Trinity Hamm; Marcin Nowicki; Sarah Boggess; William Klingeman; Denita Hadziabdic; Matthew Huff; Margaret Staton; Robert Trigiano. 2021. "Development and Characterization of 15 Novel Genomic SSRs for Viburnum farreri." Plants 10, no. 3: 487.

Original research
Published: 11 July 2020 in Ecology and Evolution
Reads 0
Downloads 0

Cornus kousa (Asian dogwood), an East Asia native tree, is the most economically important species of the dogwood genus, owing to its desirable horticultural traits and ability to hybridize with North America‐native dogwoods. To assess the species genetic diversity and to better inform the ongoing and future breeding efforts, we assembled an herbarium and arboretum collection of 131 noncultivated C. kousa specimens. Genotyping and capillary electrophoresis analyses of our C. kousa collection with the newly developed genic and published nuclear genomic microsatellites permitted assessment of genetic diversity and evolutionary history of the species. Regardless of the microsatellite type used, the study yielded generally similar insights into the C. kousa diversity with subtle differences deriving from and underlining the marker used. The accrued evidence pointed to the species distinct genetic pools related to the plant country of origin. This can be helpful in the development of the commercial cultivars for this important ornamental crop with increased pyramided utility traits. Analyses of the C. kousa evolutionary history using the accrued genotyping datasets pointed to an unsampled ancestor population, possibly now extinct, as per the phylogeography of the region. To our knowledge, there are few studies utilizing the same gDNA collection to compare performance of genomic and genic microsatellites. This is the first detailed report on C. kousa species diversity and evolutionary history inference.

ACS Style

Marcin Nowicki; Logan C. Houston; Sarah L. Boggess; Anthony S. Aiello; Miriam Payá‐Milans; Margaret E. Staton; Mitsuhiro Hayashida; Masahiro Yamanaka; Shigetoshi Eda; Robert N. Trigiano. Species diversity and phylogeography ofCornus kousa(Asian dogwood) captured by genomic and genic microsatellites. Ecology and Evolution 2020, 10, 8299 -8312.

AMA Style

Marcin Nowicki, Logan C. Houston, Sarah L. Boggess, Anthony S. Aiello, Miriam Payá‐Milans, Margaret E. Staton, Mitsuhiro Hayashida, Masahiro Yamanaka, Shigetoshi Eda, Robert N. Trigiano. Species diversity and phylogeography ofCornus kousa(Asian dogwood) captured by genomic and genic microsatellites. Ecology and Evolution. 2020; 10 (15):8299-8312.

Chicago/Turabian Style

Marcin Nowicki; Logan C. Houston; Sarah L. Boggess; Anthony S. Aiello; Miriam Payá‐Milans; Margaret E. Staton; Mitsuhiro Hayashida; Masahiro Yamanaka; Shigetoshi Eda; Robert N. Trigiano. 2020. "Species diversity and phylogeography ofCornus kousa(Asian dogwood) captured by genomic and genic microsatellites." Ecology and Evolution 10, no. 15: 8299-8312.

Journal article
Published: 03 June 2020 in Plants
Reads 0
Downloads 0

Helianthus verticillatus (Asteraceae), whorled sunflower, is a perennial species restricted to a few locations in the Southeastern United States. Habitat loss has caused H. verticillatus to become rare, and since 2014, it has been federally listed as an endangered species. As a part of the recovery plan for the restoration and protection of H. verticillatus, an efficient micropropagation protocol based on axillary shoot proliferation was developed. Various concentrations of 6-benzylaminopurine (BAP; 0 to 4.44 µM) were examined for their morphogenetic potential in the regeneration of six genotypes of H. verticillatus from the nodal explants derived from greenhouse-grown plants. Both the BAP concentration and genotype had significant effects on the regeneration capacity of H. verticillatus. Although the induced buds were observed on ½-strength Murashige and Skoog medium without plant growth regulators, a higher rate of induction and bud development were achieved on media with either 0.88 or 2.22 µM BAP, regardless of the genotype. Successful rooting of the induced shoots was achieved within four weeks after the transfer from the induction medium to the fresh ½-strength MS medium, but the rooting efficiency was dependent on the plant’s genetic background. Regenerated plantlets, with well-developed shoots and roots, were acclimatized successfully to greenhouse conditions with a 97% survival rate. Simple sequence repeats (SSRs) markers were employed to assess the genetic uniformity of the micropropagated plants of H. verticillatus. No extraneous bands were detected between regenerants and their respective donor plants, confirming the genetic fidelity and stability of regenerated plants. To our knowledge, the protocol developed in this study is the first such report for this endangered species.

ACS Style

Marzena Nowakowska; Žaklina Pavlović; Marcin Nowicki; Sarah L. Boggess; Robert N. Trigiano. In Vitro Propagation of an Endangered Helianthus verticillatus by Axillary Bud Proliferation. Plants 2020, 9, 1 .

AMA Style

Marzena Nowakowska, Žaklina Pavlović, Marcin Nowicki, Sarah L. Boggess, Robert N. Trigiano. In Vitro Propagation of an Endangered Helianthus verticillatus by Axillary Bud Proliferation. Plants. 2020; 9 (6):1.

Chicago/Turabian Style

Marzena Nowakowska; Žaklina Pavlović; Marcin Nowicki; Sarah L. Boggess; Robert N. Trigiano. 2020. "In Vitro Propagation of an Endangered Helianthus verticillatus by Axillary Bud Proliferation." Plants 9, no. 6: 1.

Research article
Published: 01 June 2020 in Plant Disease
Reads 0
Downloads 0

Helianthus verticillatus (whorled sunflower: Asteraceae) is a rare and endangered species growing naturally only in a few locations in the southeastern United States. This sunflower grows to a height between 2 and 4 m and produces spectacular sprays of yellow flower heads in late August through October. The species has potential as a landscape plant because of its showy characteristics, ease of cultivation, and it attracts native pollinators and other insect visitors. Dark spots, caused by Alternaria alternata (Edwards et al. 2017), occur commonly on senescing lower leaves beginning in late June. In July and August 2019, plants grown in the nursery compound at the University of Tennessee and field locations developed < 4 mm diam. circular leaf spots with small, white, papery centers surrounded by a thin band of purple, almost black, host tissue. There were no signs of a potential pathogen. Symptomatic leaves from the nursery were collected in mid-July and washed in water for 10 min, surface disinfested with 1.25% NaClO for 8 min, and rinsed with sterile water. Excised lesions and healthy tissues were cultured on potato dextrose agar (PDA) supplemented with 10 mg rifampicin/liter, and incubated at room temperature. White cottony mycelium grew from lesions and after 10 days became gray/black and appressed to the medium. Conidia were not present, but a red pigment in the medium was evident. Cultures of two isolates were air- dried and pigments extracted with 100% ethyl acetate. The UV-visible spectrum of the pigment was very similar to a cercosporin standard. Genomic DNA from mycelium of two isolates was amplified using ITS1 and ITS4 primers (White et al. 1990) and sequenced. The sequence from one isolate was identical to Cercospora apii s. lat. from Lobelia cardinalis (GenBank KY940304: Trigiano et al. 2018), and another isolate differed at one base. Sequences were deposited in Genbank (MN587826, MN587827). The USDA fungal database (Farr and Rossman, 2019) reported C. helianthi and C. helianthicola on several sunflower species in the world and the ITS sequence of C. helianthicola (Yuliarni et al, 2013: KC776156.1) was identical except at two positions to C. apii s. lat. (Trigiano et al. 2018) and isolates in this report. Isolates of Cercospora from sunflower were not included in a recent treatment of the genus, but members of the former C. apii s. lat. complex were placed into three clades (Bakhshi et al. 2018). Six healthy leaves were surface disinfested, dissected bilaterally, and placed on 1.5% water agar in Petri dishes. The upper surfaces of four half leaves were inoculated with ∼5 mm diam. plugs of Cercospora sp. mycelia grown on PDA for 7 days. Two fungal isolates were tested (four half-leaves/isolate). The remaining four half-leaves were treated with sterile PDA agar plugs as controls. All cultures were incubated at ∼22°C for 10 days. Within 5-7 days, half-leaves paired with the fungus had water-soaked, necrotic lesions with slight reddening of surrounding tissue; white papery centers were absent ostensibly because of the high moisture within the Petri dishes. Half-leaves treated with sterile plugs remained green and healthy. Cercospora sp. was re-isolated from lesions, and we concluded from the completion of Koch’s postulates, the production of cercosporin and ITS sequences that the disease was caused by a Cercospora sp. This fungus does not kill plants, but causes cosmetic damage on ornamental plantings of H. verticillatus during late stage of growth and after flowering.

ACS Style

R. N. Trigiano; H. Dominguez-McLaughlin; C. Lawton; K. D. Gwinn; S. L. Boggess. First Report of a Cercospora Species Causing a Leaf Spot on the Whorled Sunflower, Helianthus verticillatus, in the United States. Plant Disease 2020, 104, 1863 -1863.

AMA Style

R. N. Trigiano, H. Dominguez-McLaughlin, C. Lawton, K. D. Gwinn, S. L. Boggess. First Report of a Cercospora Species Causing a Leaf Spot on the Whorled Sunflower, Helianthus verticillatus, in the United States. Plant Disease. 2020; 104 (6):1863-1863.

Chicago/Turabian Style

R. N. Trigiano; H. Dominguez-McLaughlin; C. Lawton; K. D. Gwinn; S. L. Boggess. 2020. "First Report of a Cercospora Species Causing a Leaf Spot on the Whorled Sunflower, Helianthus verticillatus, in the United States." Plant Disease 104, no. 6: 1863-1863.

Note
Published: 01 May 2020 in Plant Disease
Reads 0
Downloads 0
ACS Style

A. G. Chaffin; M. E. Dee; S. L. Boggess; R. N. Trigiano; E. C. Bernard; K. D. Gwinn. First Report of Chaetomium globosum Causing a Leaf Spot of Hemp (Cannabis sativa) in Tennessee. Plant Disease 2020, 104, 1540 .

AMA Style

A. G. Chaffin, M. E. Dee, S. L. Boggess, R. N. Trigiano, E. C. Bernard, K. D. Gwinn. First Report of Chaetomium globosum Causing a Leaf Spot of Hemp (Cannabis sativa) in Tennessee. Plant Disease. 2020; 104 (5):1540.

Chicago/Turabian Style

A. G. Chaffin; M. E. Dee; S. L. Boggess; R. N. Trigiano; E. C. Bernard; K. D. Gwinn. 2020. "First Report of Chaetomium globosum Causing a Leaf Spot of Hemp (Cannabis sativa) in Tennessee." Plant Disease 104, no. 5: 1540.

Original research
Published: 16 March 2020 in Ecology and Evolution
Reads 0
Downloads 0

Forest fragmentation may negatively affect plants through reduced genetic diversity and increased population structure due to habitat isolation, decreased population size, and disturbance of pollen‐seed dispersal mechanisms. However, in the case of tree species, effective pollen‐seed dispersal, mating system, and ecological dynamics may help the species overcome the negative effect of forest fragmentation. A fine‐scale population genetics study can shed light on the postfragmentation genetic diversity and structure of a species. Here, we present the genetic diversity and population structure of Cercis canadensis L. (eastern redbud) wild populations on a fine scale within fragmented areas centered around the borders of Georgia–Tennessee, USA. We hypothesized high genetic diversity among the collections of C. canadensis distributed across smaller geographical ranges. Fifteen microsatellite loci were used to genotype 172 individuals from 18 unmanaged and naturally occurring collection sites. Our results indicated presence of population structure, overall high genetic diversity (HE = 0.63, HO = 0.34), and moderate genetic differentiation (FST = 0.14) among the collection sites. Two major genetic clusters within the smaller geographical distribution were revealed by STRUCTURE. Our data suggest that native C. canadensis populations in the fragmented area around the Georgia–Tennessee border were able to maintain high levels of genetic diversity, despite the presence of considerable spatial genetic structure. As habitat isolation may negatively affect gene flow of outcrossing species across time, consequences of habitat fragmentation should be regularly monitored for this and other forest species. This study also has important implications for habitat management efforts and future breeding programs.

ACS Style

Meher A. Ony; Marcin Nowicki; Sarah L. Boggess; William E. Klingeman; John M. Zobel; Robert N. Trigiano; Denita Hadziabdic. Habitat fragmentation influences genetic diversity and differentiation: Fine‐scale population structure of Cercis canadensis (eastern redbud). Ecology and Evolution 2020, 10, 3655 -3670.

AMA Style

Meher A. Ony, Marcin Nowicki, Sarah L. Boggess, William E. Klingeman, John M. Zobel, Robert N. Trigiano, Denita Hadziabdic. Habitat fragmentation influences genetic diversity and differentiation: Fine‐scale population structure of Cercis canadensis (eastern redbud). Ecology and Evolution. 2020; 10 (8):3655-3670.

Chicago/Turabian Style

Meher A. Ony; Marcin Nowicki; Sarah L. Boggess; William E. Klingeman; John M. Zobel; Robert N. Trigiano; Denita Hadziabdic. 2020. "Habitat fragmentation influences genetic diversity and differentiation: Fine‐scale population structure of Cercis canadensis (eastern redbud)." Ecology and Evolution 10, no. 8: 3655-3670.

Research article
Published: 01 November 2019 in Plant Disease
Reads 0
Downloads 0

Cornus florida (flowering dogwood) is a popular understory tree endemic to the eastern hardwood forests of the United States. In 1996, dogwood powdery mildew caused by Erysiphe pulchra, an obligate biotrophic fungus of large bracted dogwoods, reached epidemic levels throughout the C. florida growing region. In the late 1990s, both sexual and asexual stages of E. pulchra were regularly observed; thereafter, the sexual stage was found less frequently. We examined the genetic diversity and population structure of 167 E. pulchra samples on C. florida leaves using 15 microsatellite loci. Samples were organized into two separate collection zone data sets, separated as eight zones and two zones, for the subsequent analysis of microsatellite allele length data. Clone correction analysis reduced the sample size to 90 multilocus haplotypes. Our study indicated low genetic diversity, a lack of definitive population structure, low genetic distance among multilocus haplotypes, and significant linkage disequilibrium among zones. Evidence of a population bottleneck was also detected. The results of our study indicated a high probability that E. pulchra reproduces predominately via asexual conidia and lend support to the hypothesis that E. pulchra is an exotic pathogen to North America.[Formula: see text] Copyright © 2019 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

ACS Style

Christopher R. Wyman; Denita Hadziabdic; Sarah L. Boggess; Timothy A. Rinehart; Alan S. Windham; Phillip A. Wadl; Robert N. Trigiano. Low Genetic Diversity Suggests the Recent Introduction of Dogwood Powdery Mildew to North America. Plant Disease 2019, 103, 2903 -2912.

AMA Style

Christopher R. Wyman, Denita Hadziabdic, Sarah L. Boggess, Timothy A. Rinehart, Alan S. Windham, Phillip A. Wadl, Robert N. Trigiano. Low Genetic Diversity Suggests the Recent Introduction of Dogwood Powdery Mildew to North America. Plant Disease. 2019; 103 (11):2903-2912.

Chicago/Turabian Style

Christopher R. Wyman; Denita Hadziabdic; Sarah L. Boggess; Timothy A. Rinehart; Alan S. Windham; Phillip A. Wadl; Robert N. Trigiano. 2019. "Low Genetic Diversity Suggests the Recent Introduction of Dogwood Powdery Mildew to North America." Plant Disease 103, no. 11: 2903-2912.

Research article
Published: 01 May 2019 in Plant Disease
Reads 0
Downloads 0

Powdery mildews (PMs) are important plant pathogens causing widespread damage. Here, we report the first draft genome of Erysiphe pulchra, the causative agent of PM of flowering dogwood, Cornus florida. The assembled genome was 63.5 Mbp and resulted in formation of 19,442 contigs (N50 = 11,686 bp) that contained an estimated 6,860 genes with a genome coverage of 62×. We found 102 candidate secreted effector proteins (CSEPs) in E. pulchra similar to E. necator genes that are potentially involved in disease development. This draft genome is an initial step for understanding the evolutionary history of the PMs and will also provide insight into evolutionary strategies that led to the wide host expansion and environmental adaptations so effectively employed by the PM lineages.

ACS Style

Phillip A. Wadl; Brian M. Mack; Shannon B. Beltz; Geromy G. Moore; Richard E. Baird; Timothy A. Rinehart; Thomas J. Molnar; Margaret E. Staton; Denita Hadziabdic; Robert N. Trigiano. Development of Genomic Resources for the Powdery Mildew, Erysiphe pulchra. Plant Disease 2019, 103, 804 -807.

AMA Style

Phillip A. Wadl, Brian M. Mack, Shannon B. Beltz, Geromy G. Moore, Richard E. Baird, Timothy A. Rinehart, Thomas J. Molnar, Margaret E. Staton, Denita Hadziabdic, Robert N. Trigiano. Development of Genomic Resources for the Powdery Mildew, Erysiphe pulchra. Plant Disease. 2019; 103 (5):804-807.

Chicago/Turabian Style

Phillip A. Wadl; Brian M. Mack; Shannon B. Beltz; Geromy G. Moore; Richard E. Baird; Timothy A. Rinehart; Thomas J. Molnar; Margaret E. Staton; Denita Hadziabdic; Robert N. Trigiano. 2019. "Development of Genomic Resources for the Powdery Mildew, Erysiphe pulchra." Plant Disease 103, no. 5: 804-807.

Research article
Published: 01 April 2019 in Plant Disease
Reads 0
Downloads 0

Honeysuckle leaf blight, incited by Insolibasidium deformans (C. J. Gould) Oberw. & Bandoni, infects at least 18 Lonicera species and Symphoricarpos albus (L.) Blake (Caprifoliaceae), has been reported across the northeastern and north-central USA and Canada (Gould 1945, Riffle and Watkins 1986). In early May 2018, foliar chlorosis and necrosis consistent with symptoms of I. deformans were observed on Amur honeysuckle, Lonicera maackii (Rupr.) Herder on recently matured re-growth foliage in Oak Ridge, TN arboretum borders. Beneath chlorotic lesions and often adjacent to necrotic leaf tissues, a thin, white layer of basidia and basidiospores was visible mostly on abaxial leaf surfaces. The hyaline, uninucleate, slightly curved and cylindrial basidiospores possess an apiculus on the end from which they arise from curved, transversely septate basidia (Suppl. Fig. S1). Basidiospores measured 10.2 µm (8.3 – 12.2 µm) × 6.2 µm (4.5 – 7.5 µm) (n = 30). Conidia (Glomopsis sp.) may be produced as resting spores later in the season but were not observed. Observed fungal morphology closely agrees with the description for I. deformans (Gould 1945; Oberwinkler and Bandoni 1984). Lesions were excised and total gDNA isolated and amplified with ITS1 and ITS4, and the amplicons of the plant and fungus processed according to Trigiano et al. (2016) for sequencing. The sequence for I. deformans was entered into GenBank (MH790966) and was 100% identical to GenBank I. deformans accession GU291277. The sequence for L. maackii, entered into GenBank as MH790967, was ≥ 99% identical with GenBank accession EU240695. On 29 June 2018, inoculations were made using infected Amur honeysuckle leaves held against newly emerged foliage with a hair clip on five propagated, irrigated, disease-free L. maackii plants. Non-symptomatic leaves from extra honeysuckle plants were attached to leaves on an additional 5 control plants. Plants were were held at 75±10F with a 12 hr L:D photoperiod and kept in fiber sleeves for 3 days to maintain humidity with clips and infected leaf tissues removed after the first 12 hours. Chlorosis, visible on both sides of inoculated leaves, first appeared 19 days after inoculation and necrotic leaf tissues were present 6 days later. Honeysuckle leaf blight signs and symptoms identical to those of the original disease materials were observed on 5 of 5 inoculated L. maackii plants. All controls remained disease-free. After molecular confirmation from inoculated host foliage, we conclude that I. deformans was the causal pathogen of honeysuckle leaf blight on L. maackii in Tennessee. This observation is the southernmost occurrence reported for I. deformans and consistent symptomology was also observed in early June 2018 on L. maackii in Chattanooga, TN. In contrast with a recent report from northern Kentucky (Boyce, 2018), there there is little evidence that infection has led to appreciable levels of shoot death of L. maackii shrubs in eastern Tennessee. These non-native invasive plants may serve as bridge species or a reservoir for primary inoculum to infect other susceptible honeysuckle species.

ACS Style

William Klingeman; E. C. Bernard; S. L. Boggess; G. M. Pietsch; Denita Hadziabdic; R. N. Trigiano. First Report of Honeysuckle Leaf Blight on Amur Honeysuckle (Lonicera maackii) Caused by Insolibasidium deformans in Tennessee. Plant Disease 2019, 103, 772 .

AMA Style

William Klingeman, E. C. Bernard, S. L. Boggess, G. M. Pietsch, Denita Hadziabdic, R. N. Trigiano. First Report of Honeysuckle Leaf Blight on Amur Honeysuckle (Lonicera maackii) Caused by Insolibasidium deformans in Tennessee. Plant Disease. 2019; 103 (4):772.

Chicago/Turabian Style

William Klingeman; E. C. Bernard; S. L. Boggess; G. M. Pietsch; Denita Hadziabdic; R. N. Trigiano. 2019. "First Report of Honeysuckle Leaf Blight on Amur Honeysuckle (Lonicera maackii) Caused by Insolibasidium deformans in Tennessee." Plant Disease 103, no. 4: 772.

Journal article
Published: 13 February 2019 in Scientific Reports
Reads 0
Downloads 0

Taraxacum kok-saghyz (TKS) carries great potential as alternative natural rubber source. To better inform future breeding efforts with TKS and gain a deeper understanding of its genetic diversity, we utilized de novo sequencing to generate novel genomic simple sequence repeats markers (gSSRs). We utilized 25 gSSRs on a collection of genomic DNA (gDNA) samples from germplasm bank, and two gDNA samples from historical herbarium specimens. PCR coupled with capillary electrophoresis and an array of population genetics tools were employed to analyze the dataset of our study as well as a dataset of the recently published genic SSRs (eSSRs) generated on the same germplasm. Our results using both gSSRs and eSSRs revealed that TKS has low- to- moderate genetic diversity with most of it partitioned to the individuals and individuals within populations, whereas the species lacked population structure. Nineteen of the 25 gSSR markers cross-amplified to other Taraxacum spp. collected from Southeastern United States and identified as T. officinale by ITS sequencing. We used a subset of 14 gSSRs to estimate the genetic diversity of the T. officinale gDNA collection. In contrast to the obligatory outcrossing TKS, T. officinale presented evidence for population structure and clonal reproduction, which agreed with the species biology. We mapped the molecular markers sequences from this study and several others to the well-annotated sunflower genome. Our gSSRs present a functional tool for the biodiversity analyses in Taraxacum, but also in the related genera, as well as in the closely related tribes of the Asteraceae.

ACS Style

Marcin Nowicki; Yichen Zhao; Sarah L. Boggess; Helge Fluess; Miriam Payá-Milans; Margaret E. Staton; Logan Houston; Denita Hadziabdic; Robert N. Trigiano. Taraxacum kok-saghyz (rubber dandelion) genomic microsatellite loci reveal modest genetic diversity and cross-amplify broadly to related species. Scientific Reports 2019, 9, 1 -17.

AMA Style

Marcin Nowicki, Yichen Zhao, Sarah L. Boggess, Helge Fluess, Miriam Payá-Milans, Margaret E. Staton, Logan Houston, Denita Hadziabdic, Robert N. Trigiano. Taraxacum kok-saghyz (rubber dandelion) genomic microsatellite loci reveal modest genetic diversity and cross-amplify broadly to related species. Scientific Reports. 2019; 9 (1):1-17.

Chicago/Turabian Style

Marcin Nowicki; Yichen Zhao; Sarah L. Boggess; Helge Fluess; Miriam Payá-Milans; Margaret E. Staton; Logan Houston; Denita Hadziabdic; Robert N. Trigiano. 2019. "Taraxacum kok-saghyz (rubber dandelion) genomic microsatellite loci reveal modest genetic diversity and cross-amplify broadly to related species." Scientific Reports 9, no. 1: 1-17.

Research article
Published: 01 November 2018 in Plant Disease
Reads 0
Downloads 0

Rohdea japonica (Asparagaceae: Japanese Sacred Lily) is an ornamental garden plant in the United States, but is native to eastern Asia. The species is typically evergreen in warm growing areas, but can be deciduous in colder climates, has inconspicuous flowers, and produces bright red berries that are persistent in winter. In May of 2016 and 2017, anthracnose-like, circular lesions with red borders surrounded by chlorotic tissues were observed on leaves of R. japonica at the University of Tennessee, Knoxville, TN. Signs included numerous cushion-like, dark acervuli with prominent, long, black setae formed on necrotic tissue. Conidia were single-celled, colorless, fusiform to linear, and had a mean (n = 20) length of 24.8 µm (21.3- 27.3 µm) and a mean width of 4.4 µm (4.0- 5.1 µm). The description of the disease and the fungus agreed well with the report of Colletotrichum liriopes infecting R. japonica (Kwon and Kim 2013) and Liriope muscari (Oo and Oh 2017) in Korea, except the conidia in these reports were slightly narrower. A similar disease of R. japonica caused by a Colletotrichum sp. was reported from California (French 1989). Lesions with a border of healthy tissue were excised and dipped in 70% ethanol for 30 sec, immersed in 1.3 % NaOCl for 10 min, and rinsed three times in sterile water. Tissues from the margin of lesions were transferred to half-strength potato dextrose agar (PDA) augmented with 10 mg rifampicin/liter and incubated in the dark. Two colony morphotypes were apparent after one week: a dark, black, flocculent mycelium with conidiomata and conidia, without setae, and a light brown, appressed slimy mycelium with numerous red-brown perithecia formed on orange-pigmented mycelium. The eight ascospores/ascus had a mean (n=20) length of 18.5 µm (14.4- 20.8 µm) and a mean width of 6.8 µm (5.8- 7.6 µm). A Glomerella sp. sexual stage is often associated with Colletotrichum spp., but none has been reported for C. liriopes (Réblová et al. 2011). Sclerotia (Kwon and Kim 2013; Oo and Oh 2017) were not observed in our cultures. DNA was extracted from both colony morphotypes, amplified with ITS1-S4 primers (White et al. 1990) and the amplicons sequenced. Sequences from both colony morphotypes were identical (MH005034) and aligned perfectly with GenBank accession HM585396 for C. liriopes. Sequences for five other C. liriopes entries in GenBank were the same as our sequence except there was a single nucleotide variant (C to A) at bp 494. Leaves of 10 plants were sprayed with a 1 x 105 conidia/ml suspension to run-off, and 10 control plants with sterile water. Plants in containers were placed in plastic bags and maintained in high humidity at room temperature for two days and then grown for 28 days exposed to natural light in our lab. Anthracnose symptoms appeared after 10-14 days and were identical to the original disease profile; control plants were symptomless. Only the dark black mycelium was re-isolated from lesions. We concluded that the disease on R. japonica is caused by C. liriopes. The disease does not kill plants in Tennessee, but does affect their aesthetic quality, and therefore, control measures should be developed and employed. References French, A.M. 1989. California Plant Disease Host Index. 394p. Kwon, J.-H. and J. Kim. 2013. Plant Dis. 97:559. Oo, M. M. and S.-K. Oh. 2017. Kor. J. Mycol. 45:68-73. Réblová, M., et al. 2011. Studies Mycol. 68:163-191. White, T. J., et al. 1990. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, New York.

ACS Style

R. N. Trigiano; S. L. Boggess; E. C. Bernard; A. S. Windham. First Report of a Leaf Anthracnose on Rohdea japonica (Japanese Sacred Lily) Caused by Colletotrichum liriopes (Glomerella Species) in the United States. Plant Disease 2018, 102, 2380 -2380.

AMA Style

R. N. Trigiano, S. L. Boggess, E. C. Bernard, A. S. Windham. First Report of a Leaf Anthracnose on Rohdea japonica (Japanese Sacred Lily) Caused by Colletotrichum liriopes (Glomerella Species) in the United States. Plant Disease. 2018; 102 (11):2380-2380.

Chicago/Turabian Style

R. N. Trigiano; S. L. Boggess; E. C. Bernard; A. S. Windham. 2018. "First Report of a Leaf Anthracnose on Rohdea japonica (Japanese Sacred Lily) Caused by Colletotrichum liriopes (Glomerella Species) in the United States." Plant Disease 102, no. 11: 2380-2380.

Research article
Published: 01 September 2018 in Plant Disease
Reads 0
Downloads 0

The genus Pycnantheum (Lamiaceae) includes about 19 North American species of perennial mints that tolerate dry to wet soils, depending on species, and support honeybee, native bee and butterfly pollinators (Porter 2010). Powdery mildew symptoms caused by G. monardae (G. S. Nagy) M. Scholler, U. Braun & A. Schmidt (Schollar et al. 2016), G. biocellatus (Ehrenb.) Heluta (Braun and Cooke 2012)), were seen on rooted cuttings of Monarda fistulosa L. (wild bergamot) and P. incanum (L.) Michx. (hoary mountain mint). To our knowledge, no reports exist describing powdery mildew infecting Pycnanthemum species in the United States. All plant species were grown in a University of Tennessee greenhouse at Knoxville, TN, during late July 2017. White, powdery fungal colonies were abundant on adaxial leaf surfaces and stems of M. fistulosa and P. incanum. The ellipsoid and doliiform-shaped conidia borne in chains on conidiophores measured 35.8 µm (29.8 – 41.8 µm) × 17.2 µm (15.2 – 19.3 µm) (n = 30). Conidia germinated via short, subterminal to nearly terminal germ tubes that presented lobed- or nipple-shaped appressoria. Chasmothecia were not observed at any time on either of the plant species. The morphological data for the fungus agreed well with the description provided for G. monardae (Scholler et al. 2016). Lesions were excised and total genomic DNA isolated and amplified with ITS1 and ITS4 (White et al. 1990), and the amplicons of the plant and fungus processed according to Trigiano et al. (2016) for sequencing. The sequence for G. monardae was entered into GenBank (MG677127) and was 100% identical to GenBank G. biocellatus (now G. monardae) accessions AB307675, AB307667 and AB307668. In September 2017, foliage of each of five propagated, irrigated, disease-free plants of P. virginianum (L.) Rob. & Fernald, P. muticum (Michx.) Persh., P. incanum, and Cunila origanoides (L.) Britton (American dittany) grown in the greenhouse were brushed with leaves cut from infected Pycnanthemum spp. plants. Inoculated plants, along with five un-inoculated control plants per species, were covered with fiber sleeves for 3 days. By 6 days after inoculation, powdery mildew signs were observed on 5 of 5 inoculated P. incanum and C. origanoides, and 4 of 5 P. virginianum and P. muticum plants. All controls remained disease-free. Signs and symptoms were identical to those of the original disease. We conclude that G. monardae is the causal pathogen of powdery mildew of Pycnanthemum species and C. origanoides. Because G. monardae and closely related species have a very extensive host range in the mint family (Braun and Cook 2012), these native plants may serve as bridge species or a reservoir for primary inoculum to infect other susceptible mint species.

ACS Style

William Klingeman; E. C. Bernard; S. L. Boggess; G. M. Pietsch; R. N. Trigiano. First Report of Powdery Mildew on Mountain Mints (Pycnanthemum spp.) Caused by Golovinomyces monardae in the United States. Plant Disease 2018, 102, 1849 .

AMA Style

William Klingeman, E. C. Bernard, S. L. Boggess, G. M. Pietsch, R. N. Trigiano. First Report of Powdery Mildew on Mountain Mints (Pycnanthemum spp.) Caused by Golovinomyces monardae in the United States. Plant Disease. 2018; 102 (9):1849.

Chicago/Turabian Style

William Klingeman; E. C. Bernard; S. L. Boggess; G. M. Pietsch; R. N. Trigiano. 2018. "First Report of Powdery Mildew on Mountain Mints (Pycnanthemum spp.) Caused by Golovinomyces monardae in the United States." Plant Disease 102, no. 9: 1849.

Note
Published: 01 February 2018 in Plant Disease
Reads 0
Downloads 0
ACS Style

R. N. Trigiano; S. L. Boggess; Bonnie Ownley. First Report of an Aerial Blight of Chrysogonum virginianum (Green and Gold) Caused by Sclerotinia sclerotiorum in the United States. Plant Disease 2018, 102, 450 .

AMA Style

R. N. Trigiano, S. L. Boggess, Bonnie Ownley. First Report of an Aerial Blight of Chrysogonum virginianum (Green and Gold) Caused by Sclerotinia sclerotiorum in the United States. Plant Disease. 2018; 102 (2):450.

Chicago/Turabian Style

R. N. Trigiano; S. L. Boggess; Bonnie Ownley. 2018. "First Report of an Aerial Blight of Chrysogonum virginianum (Green and Gold) Caused by Sclerotinia sclerotiorum in the United States." Plant Disease 102, no. 2: 450.

Note
Published: 01 February 2018 in Plant Disease
Reads 0
Downloads 0
ACS Style

William Klingeman; E. C. Bernard; S. L. Boggess; G. M. Pietsch; J. T. Brosnan; R. N. Trigiano. First Report of Powdery Mildew on Rescuegrass (Bromus catharticus) Caused by Blumeria graminis in Tennessee. Plant Disease 2018, 102, 449 -449.

AMA Style

William Klingeman, E. C. Bernard, S. L. Boggess, G. M. Pietsch, J. T. Brosnan, R. N. Trigiano. First Report of Powdery Mildew on Rescuegrass (Bromus catharticus) Caused by Blumeria graminis in Tennessee. Plant Disease. 2018; 102 (2):449-449.

Chicago/Turabian Style

William Klingeman; E. C. Bernard; S. L. Boggess; G. M. Pietsch; J. T. Brosnan; R. N. Trigiano. 2018. "First Report of Powdery Mildew on Rescuegrass (Bromus catharticus) Caused by Blumeria graminis in Tennessee." Plant Disease 102, no. 2: 449-449.

Note
Published: 01 January 2018 in Plant Disease
Reads 0
Downloads 0
ACS Style

R. N. Trigiano; S. L. Boggess; K. D. Gwinn. First Report of Cercospora apii s. lat. Causing a Leaf Spot on Cardinal Flower (Lobelia cardinalis) in the United States. Plant Disease 2018, 102, 252 -252.

AMA Style

R. N. Trigiano, S. L. Boggess, K. D. Gwinn. First Report of Cercospora apii s. lat. Causing a Leaf Spot on Cardinal Flower (Lobelia cardinalis) in the United States. Plant Disease. 2018; 102 (1):252-252.

Chicago/Turabian Style

R. N. Trigiano; S. L. Boggess; K. D. Gwinn. 2018. "First Report of Cercospora apii s. lat. Causing a Leaf Spot on Cardinal Flower (Lobelia cardinalis) in the United States." Plant Disease 102, no. 1: 252-252.

Research article
Published: 01 January 2018 in Plant Disease
Reads 0
Downloads 0

Green-and-gold or Goldenstar (Chrysogonum virginianum L.: Asteraceae: Heliantheae) is a low-growing, shade-tolerant, perennial flowering groundcover that occurs naturally in moist, woodland environments in the eastern United States. Several variants of the plant are available commercially, and generally considered easy-to-grow and relatively disease-free, except for some anecdotal reports of “mildew”. The fungus causing powdery mildew on this plant has never been identified and Koch’s postulates have not been completed. Plants growing in ornamental settings from Knoxville, TN in 2015‒17 exhibited signs and symptoms of powdery mildew that included superficial, scanty and patchy, white mycelia and hyaline conidiophores and conidia on both surfaces of the laminae, which were slightly cupped and upturned from the mid-vein to the margins compared to uninfected leaves. By June, mycelia were tightly appressed to the leaf surface, gray and crusty, and sporulation was greatly reduced. Infected leaf pieces were mounted in water or stained with Trypan blue. Conidia (n = 30), which lacked fibrosin bodies and were borne in chains, were ellipsoid or doliiform, rarely cylindrical, had a L:W between 1.7 and 2.1, and measured 36.6 µm (32.9 – 42.0 µm) by 18.6 µm (15.6 – 20.5 µm). Conidia germinated sub-terminally and produced nipple-shaped appressoria. The morphology of the fungus agreed with the description for Golovinomyces spadiceus that occurs on species in the Heliantheae (Braun and Cook 2012). Chasmothecia were not detected during any of the three growing seasons. Total genomic DNA was prepared from mycelium, conidiophores and conidia from leaves and amplified with ITS1 and ITS4 primers (White et al. 1990). Amplicons were purified before sequencing (Trigiano et al. 2016) and the sequences deposited in GenBank (MF460422). The sequence was 100% identical to G. ambrosiae reported on Helianthus annuus (KM657962) and H. verticillatus (KM657962). The sequence for C. virginianum was also entered in Genbank (MF460421). However, ITS sequencing is not sufficient to delineate G. ambrosiae from G. spadiceus (Takamatsu et al. 2013). Morphologically, G. spadiceus conidia are < 20 µm wide, whereas G. ambrosiae conidia can be wider (Braun and Cook 2012). Five C. virginianum powdery mildew-free plants were inoculated by rubbing the adaxial surface of leaves with leaves having signs of powdery mildew; two plants were rubbed with healthy leaves as controls. Plants from all treatments were covered with plastic bags for 2 days and then removed. After 10 days, 4 plants inoculated with powdery mildew leaves from C. virginianum exhibited the same signs and symptoms as described originally from infected C. virginianum plants. All control plants remained disease-free. Our conclusion is that G. spadiceus is the cause of powdery mildew on C. virginianum. The disease on C. virginianum appears to be more cosmetic than detrimental as flowering and growth of the plants are not noticeably affected. This is the first report that provides completed Koch’s postulates for this disease in the United States.

ACS Style

R. N. Trigiano; S. L. Boggess; E. C. Bernard. First Report of Powdery Mildew Caused by Golovinomyces spadiceus on Green and Gold (Chrysogonum virginianum) in the United States. Plant Disease 2018, 102, 252 -252.

AMA Style

R. N. Trigiano, S. L. Boggess, E. C. Bernard. First Report of Powdery Mildew Caused by Golovinomyces spadiceus on Green and Gold (Chrysogonum virginianum) in the United States. Plant Disease. 2018; 102 (1):252-252.

Chicago/Turabian Style

R. N. Trigiano; S. L. Boggess; E. C. Bernard. 2018. "First Report of Powdery Mildew Caused by Golovinomyces spadiceus on Green and Gold (Chrysogonum virginianum) in the United States." Plant Disease 102, no. 1: 252-252.

Research article
Published: 26 July 2017 in PLOS ONE
Reads 0
Downloads 0

Cornus florida (flowering dogwood) and C. nuttallii (Pacific dogwood) are North American native tree species that belong to the big-bracted group of dogwoods. Cornus species are highly valued for their ornamental characteristics, and have fruits that contain high fat content for animals. Also, they are an important understory tree in natural forests. Dogwood anthracnose, caused by Discula destructiva, was observed in the late 1970s on the east and west coasts of the United States and by 1991 had quickly spread throughout most of the native ranges of C. florida and C. nuttalli. We investigated the genetic diversity and population structure of 93 D. destructiva isolates using 47 microsatellite loci developed from the sequenced genome of the type strain of D. destructiva. Clone-corrected data indicated low genetic diversity and the presence of four genetic clusters that corresponded to two major geographic areas, the eastern United States and the Pacific Northwest, and to the two collection time periods when the isolates were collected (pre- and post-1993). Linkage disequilibrium was present in five out of six subpopulations, suggesting that the fungus only reproduced asexually. Evidence of population bottlenecks was indicated across four identified genetic clusters, and was probably the result of the limited number of founding individuals on both coasts. These results support the hypothesis that D. destructiva is an exotic pathogen with independent introductions on the east and west coasts of North America. We also tested the cross-amplification of these microsatellite primers to other Discula species. Genomic DNA from 17 isolates of four other Discula species and two isolates of Juglanconis species (formerly Melanconis species) were amplified by 17 of 47 primer pairs. These primers may be useful for investigating the genetic diversity and population structure of these Discula species.

ACS Style

Kristie Mantooth; Denita Hadziabdic; Sarah Boggess; Mark Windham; Stephen Miller; Guohong Cai; Joseph Spatafora; Ning Zhang; Meg Staton; Bonnie Ownley; Robert Trigiano. Confirmation of independent introductions of an exotic plant pathogen of Cornus species, Discula destructiva, on the east and west coasts of North America. PLOS ONE 2017, 12, e0180345 .

AMA Style

Kristie Mantooth, Denita Hadziabdic, Sarah Boggess, Mark Windham, Stephen Miller, Guohong Cai, Joseph Spatafora, Ning Zhang, Meg Staton, Bonnie Ownley, Robert Trigiano. Confirmation of independent introductions of an exotic plant pathogen of Cornus species, Discula destructiva, on the east and west coasts of North America. PLOS ONE. 2017; 12 (7):e0180345.

Chicago/Turabian Style

Kristie Mantooth; Denita Hadziabdic; Sarah Boggess; Mark Windham; Stephen Miller; Guohong Cai; Joseph Spatafora; Ning Zhang; Meg Staton; Bonnie Ownley; Robert Trigiano. 2017. "Confirmation of independent introductions of an exotic plant pathogen of Cornus species, Discula destructiva, on the east and west coasts of North America." PLOS ONE 12, no. 7: e0180345.