Gray mold of strawberry (Fragaria ananassa) caused by a rare pink-colored isolate of Botrytis cinerea in China

Abstract

Botrytis cinerea is a major pathogen causing gray mold disease on strawberry (Fragaria ananassa). Here, one pink-colored B. cinerea strain GS5–15 was isolated from diseased strawberry fruit, and its identity was confirmed by both morphological and molecular methods. Besides showing typical culture morphology of B. cinerea, strain GS5–15 produced pink mycelium on potato dextrose agar. A 354-bp DNA fragment was detected in strain GS5–15 by using PCR with B. cinerea-specific primers Bc-f/Bc-r, indicating that it belonged to B. cinerea. BLASTn analysis showed that the sequences of ITS, G3PDH, HSP60, and RPB2 were 99–100% identical to the corresponding sequences of other B. cinerea strains, and the phylogenetic analysis based on concatenated G3PDH, HSP60 and RPB2 sequences also showed that strain GS5–15 was clustered with reference strains of B. cinerea. Re-inoculation of strain GS5–15 on strawberry fruit displayed typical gray mold symptom, and a fungus showing colony morphology similar to the original strain was re-isolated from the diseased fruits. Therefore, B. cinerea strain GS5–15 was determined to be the causal agent of gray mold on strawberry in China. To our knowledge, this is the first record of pink-colored B. cinerea infecting strawberry in China.