Pathogenicity Of The Botrytis Cinerea Isolate Taian In Tomato

Gray mold,caused by fungal pathogen Botrytis cinerea,is an important disease that causes extensive damage to a wide range of economically important crops globally.Tomato is an important economic crop vulnerable to a variety of pathogens.Tomato gray mold is a major thread to tomato,especially in greenhouse.At present,no effective disease-resistant varieties have been found in tomatoes.To understand the pathogenicity of B.cinerea races is required for efficiency resistance breeding.Thus,we isolated a new race of B.cinerea and compared its pathogenicity with that of the reference strain B05.10.Firstly,the pathogen was isolated from tomato leaves with gray mold disease in Tai’an of Shandong Province.Through ITS sequencing and artificial inoculation,it was determined that the pathogen was a new race,named Taian.Comparing Taian strain with B05.10,we found that Taian and B05.10 had similar mycelial growth rate,while they showed significant differences in colony morphology and spore morphology.Taian has produced less spore production compared with B05.10 on PDA medium.This result suggests that Taian and B05.10 have differences genetic background.We use cultivated tomatoes M82,CM,AC,and MM to measure the pathogenicity of the two races by infecting detached tomato leaves.The results showed that,in M82 and CM,the Taian strain had significantly reduced pathogenicity compared to B05.10.However,in AC and MM,there were no significant difference in pathogenicity of Taian and B05.10.JA signaling pathway is essential for plant immunity to necrotrophic pathogen.To determine the relationship between pathogenicity of Botrytis cinerea and JA-induced resistance in plant,we infected the two strains of Botrytis cinerea on JA-defect mutants spr2,spr8.The results show that,after infection,spr2 and spr8 were more susceptible compared to WT.q PCR show that Botrytis cinerea infection strongly induced JA responsive genes PI-II and PR-STH2 in WT but not in spr2 or spr8.It suggests that plant resistance to both Taian and B05.10 is dependent on JA signaling.Further,we exam if the difference of pathogenicity between Taian and B05.10 is related to JA induced defense in host.Treated with 50 μM JA before pathogen infection on,M82 and AC highly expressed PI-II when inoculated with Taian and B05.10.In M82,JA treatment significantly increased plant resistance to both Taian and B05.10.In AC,treatment of JA could not significantly induce resistance to B05.10,but significantly increased resistance to Taian.This study showed that interaction of Botrytis cinerea and tomato is divergent caused by the genetic background of host and pathogen.The JA induced resistance is different in AC and M82,which is related to plant immunity to Botrytis cinerea.In M82,the pathogenicity is significantly different between Taian and B05.10,while in AC they did not show significant difference.It indicates that the interaction of Botrytis cinerea and tomato is correlated with host JA signaling.Thus,this study provided new information about Botrytis cinerea and plant interaction and tomato resistance breeding.