Short communicationA new disease of mung bean caused by Botrytis cinerea

- This study is the first report of Botrytis cinerea causing gray mold on mung bean worldwide.
- B. cinerea was confirmed by morphological and molecular identification.
- Pathogenicity tests indicated that B. cinerea had a wide host range.
- All isolates tested were belonged to the transposa group by specific PCR detection in this study.

Gray mold caused by Botrytis cinerea, a ubiquitous and destructive plant pathogen, is an important disease of various crops including orchard crops, vegetables and ornamental plants. In June 2012, symptoms similar to gray mold were observed on mung bean (Vigna radiata) plants in Yongchuan, Chongqing, China. To confirm the causal agent, the pathogen was isolated and six fungal isolates were identified based on morphological and molecular characterization. The six isolates showed similar morphology to Botrytis cinerea. The rDNA-ITS sequences of the six isolates showed 99% identity to reported B. cinerea strains. The two specific primer pairs for B. cinerea, C729+/C729− and Bc108+/Bc563−, produced target fragments of 700-bp and 450-bp, respectively, in all six isolates, and their sequences displayed 99-100% identity to known B. cinerea strains. All of the isolates harbored two transposable elements of B. cinerea, Flipper and Boty, which indicated that they all belonged to the transposa group. Subsequently, pathogenicity tests demonstrated the pathogen was virulent not only on mung bean but also on other legume crops, including Phaseolus vulgaris, Vigna unguiculata, Vigna angularis, Pisum sativum, Vicia faba, and Glycine max. The results of morphological and molecular identification combined with pathogenicity tests confirmed that the pathogen isolated from mung bean was B. cinerea. To our knowledge, this is the first report of B. cinerea causing gray mold on mung bean in the world.