Physiological and biochemical characteristics of boscalid resistant isolates of Sclerotinia sclerotiorum from asparagus lettuce  

作　　者：SHI Dong-ya LI Feng-jie ZHANG Zhi-hui XU Qiao-nan CAO Ying-ying Jane Ifunanya MBADIANYA LI Xin WANG Jin CHEN Chang-jun 

机构地区：[1]Department of Pesticide Science,College of Plant Protection,Nanjing Agricultural University,Nanjing 210095,P.R.China [2]Jiangsu Pesticide Research Institute Co.,Ltd.,Nanjing 210046,P.R.China

出　　处：《Journal of Integrative Agriculture》2023年第12期3694-3708,共15页农业科学学报（英文版）

基　　金：supported by the Jiangsu Provincial Key Research and Development, China (BE2021361);the Jiangsu Agriculture Science and Technology Innovation Fund ((CX(21)2037 and CX(22)3072));the National Natural Science Foundation of China (31672065)。

摘　　要：Laboratory mutants of Sclerotinia sclerotiorum(Lib)de Bary,resistant to boscalid,have been extensively characterized.However,the resistance situation in the lettuce field remains largely elusive.In this study,among the 172 S.sclerotiorum isolates collected from asparagus lettuce field in Jiangsu Province,China,132 isolates(76.74%)exhibited low-level resistance to boscalid(Bos^(LR)),with a discriminatory dose of 5μg mL-1.In comparison to the boscalid-sensitive(BosS)isolates,most Bos^(LR)isolates demonstrated a slightly superior biological fitness,as evidenced by data on mycelial growth,sclerotium production and pathogenicity.Moreover,most Bos^(LR)isolates showed comparable levels of oxalic acid(OA)accumulation,increased exopolysaccharide(EPS)content and reduced membrane permeability when compared to the BosS isolates.Nevertheless,their responses to distinct stress factors diverged significantly.Furthermore,the effectiveness of boscalid in controlling Bos^(LR)isolates on radish was diminished compared to its efficacy on BosS isolates.Genetic mutations were identified in the SDH genes of Bos^(LR)isolates,revealing the existence of three resistant genotypes:I(^(A11V)at SDHB,SDHB^(A11V)),II(^(Q38R)at SDHC,SDHC^(Q38R))and III(SDHB^(A11V)+SDHC^(Q38R)).Importantly,no cross-resistance was observed between boscalid and other fungicides such as thifluzamide,pydiflumetofen,fluazinam,or tebuconazole.Our molecular docking analysis indicated that the docking total score(DTS)of the type I resistant isolates(1.3993)was lower than that of the sensitive isolates(1.7499),implying a reduced affinity between SDHB and boscalid as a potential mechanism underlying the boscalid resistance in S.sclerotiorum.These findings contribute to an enhanced comprehension of boscalid’s mode of action and furnish valuable insights into the management of boscalid resistance.

关 键 词：Sclerotinia sclerotiorum BOSCALID asparagus lettuce SDHB^(A11V) SDHC^(Q38R) 

分 类 号：S432.4[农业科学—植物病理学]