“Rhizomania” of sugar beet is a soilborne disease complex comprised of beet necrotic yellow vein virus (BNYVV) and its plasmodiophorid vector, Polymyxa betae. Although BNYVV is considered the causal agent of rhizomania, additional viruses frequently accompany BNYVV in diseased roots. In an effort to better understand the virus cohort present in sugar beet roots exhibiting rhizomania disease symptoms, five independent RNA samples prepared from diseased beet seedlings reared in a greenhouse or from field-grown adult sugar beet plants and enriched for virus particles were subjected to RNAseq. In all but a healthy control sample, the technique was successful at identifying BNYVV and provided sequence reads of sufficient quantity and overlap to assemble > 98% of the published genome of the virus. Utilizing the derived consensus sequence of BNYVV, infectious RNA was produced from cDNA clones of RNAs 1 and 2. The approach also enabled the detection of beet soilborne mosaic virus (BSBMV), beet soilborne virus (BSBV), beet black scorch virus (BBSV), and beet virus Q (BVQ), with near-complete genome assembly afforded to BSBMV and BBSV. In one field sample, a novel virus sequence of 3682 nt was assembled with significant sequence similarity and open reading frame (ORF) organization to members within the subgenus Alphanecrovirus (genus Necrovirus; family Tombusviridae). Construction of a DNA clone based on this sequence led to the production of the novel RNA genome in vitro that was capable of inducing local lesion formation on leaves of Chenopodium quinoa. Additionally, two previously unreported satellite viruses were revealed in the study; one possessing weak similarity to satellite maize white line mosaic virus and a second possessing moderate similarity to satellite tobacco necrosis virus C. Taken together, the approach provides an efficient pipeline to characterize variation in the BNYVV genome and to document the presence of other viruses potentially associated with disease severity or the ability to overcome resistance genes used for sugar beet rhizomania disease management.

Fusarium head blight (FHB) and the occurrence of mycotoxins is the largest food safety threat to malting and brewing grains. Worldwide surveys of commercial beers have reported that the trichothecene mycotoxin deoxynivalenol (DON) is the most frequent contaminant in beer. Although the DON content of grain generally declines during steeping due to its solubilization, Fusarium spp. can continue to grow and produce DON from steeping through the early kilning stage of malting. DON present on malt is largely extracted into beer. The objective of the current study was to localize the growth of Fusarium spp. within FHB-infected kernels by developing an improved method and to associate fungal growth with the production of DON during malting. FHB-infected barley, wheat, rye, and triticale grains that exhibited large increases in the amount of Fusarium Tri5 DNA and trichothecene mycotoxins following malting were screened for hyphal localization. The growth of fungal hyphae associated with grain and malt was imaged by scanning electron microscopy and confocal laser-scanning microscopy assisted with WGA-Alexa Fluor 488 staining, respectively. In barley, hyphae were present on or within the husk, vascular bundle, and pericarp cavities. Following malting, vast hyphal growth was observed not only in these regions but also in the aleurone layer, endosperm, and embryo. Extensive fungal growth was also observed following malting of wheat, rye, and triticale. However, these grains already had an extensive internal presence of Fusarium hyphae in the unmalted grain, thus representing an enhanced chance of fungal expansion during the malting. [ ] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY 4.0 International license .

Spot form net blotch (SFNB), caused by the necrotrophic fungal pathogen Pyrenophora teres f. maculata (Ptm), is a foliar disease of barley that results in significant yield losses in major growing regions worldwide. Understanding the host-parasite interactions between pathogen virulence/avirulence genes and the corresponding host susceptibility/resistance genes is important for the deployment of genetic resistance against SFNB. Two recombinant inbred mapping populations were developed to characterize genetic resistance/susceptibility to the Ptm isolate 13IM8.3, which was collected from Idaho (ID). An Illumina Infinium array was used to produce a genome-wide marker set. Quantitative trait loci (QTL) analysis identified ten significant resistance/susceptibility loci, with two of the QTL being common to both populations. One of the QTL on 5H appears to be novel, while the remaining loci have been reported previously. Single nucleotide polymorphisms (SNPs) closely linked to or delimiting the significant QTL have been converted to user-friendly markers. Loci and associated molecular markers identified in this study will be useful in genetic mapping and deployment of the genetic resistance to SFNB in barley.

Common root rot (CRR) and crown rot (CR), caused by Bipolaris sorokiniana and Fusarium species, respectively, can cause significant yield losses in cereal crops. To assess the prevalence, incidence, and severity of these diseases in North Dakota, wheat samples were collected from spring wheat fields across the state in 2012, 2013, and 2014. Based on subcrown internode symptoms, a greater incidence and severity of CRR was observed in 2012 (warm and dry year) than in 2013 and 2014. Also, the Northwestern Glaciated Plains and Northwestern Great Plains ecoregions showed greater CRR incidence and severity compared with the Northern Glaciated Plains and Lake Agassiz Plains ecoregions in the state. B. sorokiniana and Fusarium species, including Fusarium acuminatum, Fusarium avenaceum, Fusarium culmorum, Fusarium graminearum, Fusarium equiseti, Fusarium pseudograminearum, Fusarium oxysporum, Fusarium redolens, Fusarium sporotrichioides, and Fusarium solani were isolated and identified from the root and crown tissues of the wheat samples. B. sorokiniana was isolated more frequently than other fungal species in all sampled years and ecoregions of North Dakota. F. acuminatum, F. avenaceum, F. culmorum, F. equiseti, F. graminearum, F. pseudograminearum, and F. redolens were pathogenic causing infections on seedlings of the two wheat genotypes (ND652 and Alsen), whereas isolates of F. oxysporum and F. solani were nonpathogenic and considered as secondary invaders associated with the root and CR diseases. Evaluation of some spring wheat genotypes for reactions to one B. sorokiniana isolate at seedling and adult plant stages, and one F. culmorum isolate at the seedling stage, indicated that susceptibility to these pathogens varied among different wheat genotypes tested. This study provides useful information on fungal species associated with CRR and CR of wheat in North Dakota and on resistant/susceptible reactions of some spring wheat lines to the different fungal isolates evaluated.

Minnesota is the top sugar beet (Beta vulgaris L.) producing state in the United States. In September 2018, foliar symptoms were first observed on older sugar beet leaves in about 3% of the cultiva...