Grey mould, caused by Botrytis cinerea, is an increasingly destructive disease of ginseng (Panax ginseng) in China. However, the extent of variation in the morphological characteristics of fungal colonies, genetic background and pathogenicity of different strains of this pathogen remains unknown. In this study, we isolated and identified 102 isolates of B. cinerea from ginseng. Among these, the sclerotial phenotype was dominant, followed by the mycelial and conidial phenotypes, with the proportion of each phenotype in the pathogen population showing no obvious variance across three provinces. Isolates were separated into three groups with differing pathogenicity, based on the diameter of the lesions they caused in pathogenicity tests; moderate-pathogenicity isolates were dominant, followed by strong- and weak-pathogenicity isolates. Variation was observed in the pathogenicity of isolates from three provinces. The Nei’s genetic diversity index and the Shannon’s information index of isolates from Jilin province was highest, followed by those from Liaoning, while isolates from Heilongjiang displayed the lowest genetic diversity. Furthermore, most of the genetic variance was found within the geographically defined B. cinerea populations; the low-genetic variance among populations was probably counteracted by gene flow. Results from this study provide a base understanding of genetic and pathogenic variation in B. cinerea populations from the main ginseng-growing regions of China, which will be helpful for further research and control of grey mould of ginseng.

Rice black-streaked dwarf virus (RBSDV) is the main pathogen causing maize rough dwarf disease (MRDD) in China. Typical enation symptoms along the abaxial leaf veins prevail in RBSDV-infected maize inbred line B73 (susceptible to RBSDV), but not in X178 (resistant to RBSDV). Observation of the microstructures of epidermal cells and cross section of enations from RBSDV-infected maize leaves found that the increase of epidermal cell and phloem cell numbers is associated with enation formation. To identify proteins associated with enation formation and candidate proteins against RBSDV infection, comparative proteomics between B73 and X178 plants were conducted using isobaric tags for relative and absolute quantitation (iTRAQ) with leaf samples at the enation forming stage. The proteomics data showed that 260 and 316 differentially expressed proteins (DEPs) were identified in B73 and X178, respectively. We found that the majority of DEPs are located in the chloroplast and cytoplasm. Moreover, RBSDV infection resulted in dramatic changes of DEPs enriched by the metabolic process, response to stress and the biosynthetic process. Strikingly, a cell number regulator 10 was significantly down-regulated in RBSDV-infected B73 plants. Altogether, these data will provide value information for future studies to analyze molecular events during both enation formation and resistance mechanism to RBSDV infection.