Chinese chestnut (Castanea mollissima Blume) can be infested by Dryocosmus kuriphilus Yasumatsu, resulting in gall formation and yield losses. Research on the control of gall wasps using genomics approaches is rarely reported. We used RNA-seq to investigate the dynamic changes in the genes of a chestnut species (C. mollissima B.) during four gall-formation stages caused by D. kuriphilus. A total of 21,306 genes were annotated by BLAST in databases. Transcriptome comparison between different gall-formation stages revealed many genes that were differentially expressed compared to the control. Among these, 2410, 7373, 6294, and 9412 genes were differentially expressed in four gall-formation stages: initiation stage (A), early growth stage (B), late growth stage (C), and maturation stage (D), respectively. Annotation analysis indicated that many metabolic processes (e.g., phenylpropanoid biosynthesis, secondary metabolism, plant–pathogen interaction) were affected. Interesting genes encoding putative components of signal transduction, stress response, and transcription factors were also differentially regulated. These genes might play important roles in response to D. kuriphilus gall formation. These new data on the mechanism by which D. kuriphilus infests chestnuts could help improve chestnut resistance.

Corallococcus sp. strain EGB is a Gram-negative myxobacteria isolated from saline soil, and has considerable potential for the biocontrol of phytopathogenic fungi. However, the detailed mechanisms related to development and predatory behavior are unclear. To obtain a comprehensive overview of genetic features, the genome of strain EGB was sequenced, annotated, and compared with 10 other Corallococcus species. The strain EGB genome was assembled as a single circular chromosome of 9.4 Mb with 7916 coding genes. Phylogenomics analysis showed that strain EGB was most closely related to Corallococcus interemptor AB047A, and it was inferred to be a novel species within the Corallococcus genus. Comparative genomic analysis revealed that the pan-genome of Corallococcus genus was large and open. Only a small proportion of genes were specific to strain EGB, and most of them were annotated as hypothetical proteins. Subsequent analyses showed that strain EGB produced abundant extracellular enzymes such as chitinases and β-(1,3)-glucanases, and proteases to degrade the cell-wall components of phytopathogenic fungi. In addition, 35 biosynthetic gene clusters potentially coding for antimicrobial compounds were identified in the strain EGB, and the majority of them were present in the dispensable pan-genome with unexplored metabolites. Other genes related to secretion and regulation were also explored for strain EGB. This study opens new perspectives in the greater understanding of the predatory behavior of strain EGB, and facilitates a potential application in the biocontrol of fungal plant diseases in the future.

Tea (Camellia sinensis L.) is an economically important crop widely cultivated for leaves in China. Leaf and young shoot blights were observed on some commercial gardens of tea (Camellia sinensis, cv. Yinghong IX) in Guangzhou in April from 2013 to 2015, China. The disease occurred initially on the young leaves producing water-soaked spots. When the disease further developed, the spots merged together into large patches and killed the leaf blade. The symptoms developed on the young shoots about two weeks later. Disease incidences ranged from 20 to 30% in the affected fields. Signs of bacterial streaming from all infected leaves were observed under microscope, and no fungal mycelium or spore was found from the diseased areas. Bacterial isolates were obtained by surface-sterilizing small fragments (5 × 5 mm) of symptomatic leaf tissues in 0.5% NaOCl, rinsing the sections in sterilized water twice, and streaking on Luria-Bertani (LB) plates. Bacterial colonies were convex, beige-tan colored, round and non-mu...

This study delved into the larval development and the morphological and anatomical transformations that occur in the galls of chestnut trees (Castanea mollissima BL.) and are induced by the chestnut gall wasp Dryocosmus kuriphilus Yasumatsu (GWDK) across various stages: initial, growth, differentiation, maturity, and lignification. Chestnut galls in the five development stages were collected. Gall structural characteristics were observed with an anatomical stereomicroscope, and anatomical changes in galls were analyzed with staining and scanning electron microscope techniques. The chestnut gall wasp laid its eggs on young leaves and buds. Chestnut gall wasp parasitism caused plant tissues to form a gall chamber, with parenchyma, protective, and epidermal layers. The development of the gall structure caused by the infestation of the GWDK gall led to the weakening of the reactive oxygen species (ROS) elimination ability of the host. The accumulation of ROS led to cell wall peroxidation, resulting in structural damage and diminished host resistance, and the parenchyma layer exhibited significant nutrient supply and thickening. The thickness of the protective and epidermal layers varied notably across different growth stages. The oviposition of the chestnut gall wasp induced modifications in the original plant tissues, with gall formation being most favorable in young tissues, correlating with the maturity level of the host plant tissues. Variances in the internal structures of the galls primarily stemmed from nutrient supplementation, while those in the external structure were attributed to defensive characteristics. This research contributes a foundational understanding of gall development induced by the chestnut gall wasp in Chinese chestnut, offering valuable insights into the intricate interplay between insect infestation and plant physiology.

The Castanea mollissima ‘Chuizhili’ is an important variety of C. mollissima in breeding for dwarf chestnut and ornamental trees due to the weeping characteristic in China. In this study, the complete chloroplast genome of C. mollissima ‘Chuizhili’ was identified and sequenced by using Illumina sequencing data. The genome size is 160,799 bp, with a large single-copy (LSC, 90,430 bp) region, a small single-copy (SSC, 18,997 bp) region, and separated by a pair of 25,686 bp inverted repeat (IR) regions. A total of 130 genes are successfully annotated, including 83 protein-coding genes, 37 tRNA genes, 8 rRNA genes, and 2 pseudo-genes. The phylogenetic relationships revealed that C. mollissima ‘Chuizhili’ is closely related to Castanea henryi in Fagaceae.

Identification and Expression Profiles of the WRKY Gene Family in Pecan ( Carya illinoinensis )