四种不同植物病原真菌与多菌灵抗药性相关基因突变的比较

Comparison of mutations in the β-tubulin gene that conferresistance to carbendazim in four plant pathogenic fungi

克隆了小麦赤霉病菌 (Fusariumgraminearum)、油菜菌核病菌 (Sclerotiniasclerotiorum )、辣椒炭疽病菌 (Col letotrichumgloeosporiodies)和番茄灰霉病菌 (Botrytiscinerea) 4种病原菌的 9个菌株的 β 微管蛋白基因 ,进而与典型模式菌粗糙麦孢霉 (Neurosporacrassa)进行序列比较。结果表明 ,4种病原真菌 β 微管蛋白序列与粗糙麦孢霉具高度同源性 ;油菜菌核病菌、辣椒炭疽病菌和番茄灰霉病菌的 β 微管蛋白 198位氨基酸由Glu突变为Ala ,是导致上述病原菌产生对多菌灵 (MBC)抗药性的主要原因 ;突变位点和突变类型与其他抗多菌灵真菌一致 ,且与乙霉威 (NPC)之间存在明显负交互抗性。但小麦赤霉病MBCS 和MBCR 菌株的 β 微管蛋白序列完全一样 ,且与NPC之间不存在负交互抗性。有关小麦赤霉病菌产生抗药性的机制有待于进一步的研究。

tubulin genes from 9 strains of 4 carbendazim(MBC) resistant plant pathogenic fungi,including Fusarium graminearum,Sclerotinia sclerotiorum,Colletotrichum gloeosporiodies and Botrytis cinerea were cloned.The nucleotide sequences and their deduced amino acid sequences were compared with those of the genes from typical MBC resistant fungus, Neurospora crassa. The partial sequences of the gene and protein from the 4 plant pathogenic fungi were highly homologous to those from N.crassa. Sequence comparison between MBC sensitive (MBC S) and MBC highly resistant(MBC HR )isolates of S.sclerotiorum,C.gloeosporiodies, and B.cinerea revealed a single point mutation,which leads to change at amino acid position 198 from glutamic to alanine acid.This mutation was the same as those identified in MBC resistant field isolates of other phytopathogenic fungi,and there existed obvious negative cross resistance between MBC and diethofencarb(NPC).However,the amino acid of MBC S of F.graminearum was the same as that of MBC R,and there was no negative cross resistance to NPC.Study on the reason of carbendazim resistance in F.graminearum would be conducted.