Sensitivity Test Of Botrytis Cinerea To Boscalid And Biological Function Research Of Its Alternative Oxidase Oxidase(AOX)

Botrytis cinerea is one of the most important plant diseases,and its prevention and control depends on chemical control.And Botrytis cinerea is the most common pathogen of fungicide resistance.The Succinate dehydrogenase inhibitors（SDHIs）and Qo inhibitors（Qo Is）belong to the category of mitochondrial modern respiratory inhibitors.Based on the mycelium growth rate method to determine 240 strains of Botrytis cinerea from the collection of different region of Zhejiang province in 2017 and then analyzes the SDH gene mutations,results showed that the organism resistance molecular mechanism of boscalid-resistant strains mainly are H272R,N230I,P225F mutations in Sdh B,including B subunit 50%H272R mutated strains with C mostly subunits I80H or G85A,I93V,M158V,V168I mutations,and N230I,P225F mutations are all single point mutations.At the same time,a few special conditions were found,such as XJB17-22 strain,which is H272R mutation and sensitive to boscalid.Plants and numerous fungi protect mitochondria from interference by respiration inhibitors by expressing alternative oxidase（AOX）,which to supplement or replace the traditional mitochondrial respiratory electron transport chain.There are no more biological functions that are still to be studied in the mitochondria respiratory chain,except for the alternative respiration.In normal life activities,AOX is generally considered to be ineffective.It also reported that it had no effect on the pathogenicity of Magnaporthe grisea.However,in the study we found that AOX mutants of Botrytis cinerea which virulence was declined obviously,at the same time we also found that AOX mutants phenotypes compared with wild type strain changed dramatically,such as mutants spore production quantity is significantly reduced,producing sclerotic quantity increased significantly.In addition,the AOX mutants are sensitive to the performance of the DCFs agent（iprodione）.Meanwhile,in our study,AOX can also reduce the sensitivity of Botrytis cinerea to QoIs.For example,（1）mutants were not sensitive to SDHIs fungicides,but very sensitive to Qo Is fungicides;（2）Azoxystrobin can induce the AOX expression of the wild strain,but mutants not;（3）The contents of H₂O₂（RFU）in mutant cells increased significantly.These results indicate that AOX plays an important role in Botrytis cinerea of the growth and development,pathogenicity and the adaptation to other external stresses.