江苏省水稻赤霉病病原菌分离鉴定与致病力分析

Identification and pathogenicity test of Fusarium isolates causing Fusarium head blight in rice in Jiangsu Province

为明确江苏省水稻赤霉病的病原菌组成及致病特征,于2018—2019年从江苏省13个市41个县区采集341份水稻样品,采用组织分离法对病原菌进行分离纯化,基于翻译延伸因子(translation elongation factor-1α,TEF-1α)序列分析对分离菌株进行鉴定,通过TRI11基因序列鉴定及产毒力测定对其产毒化学型进行分析,并按照柯赫氏法则对其致病力进行验证。结果显示,从水稻样品中共分离获得病原菌392株,其中亚洲镰刀菌Fusarium asiaticum为385株,禾谷镰刀菌F.graminearum为7株。亚洲镰刀菌分为3-乙酰化脱氧雪腐镰刀菌烯醇(3-acetyldeoxynivalenol,3ADON)化学型和雪腐镰刀菌烯醇(nivalenol,NIV)化学型菌株,分别占亚洲镰刀菌总菌株数的66.8%和33.2%;禾谷镰刀菌均为(15-acetyldeoxynivalenol,15ADON)化学型。产3ADON的亚洲镰刀菌在全省范围内为优势群体,而产15ADON的禾谷镰刀菌仅在淮北地区被发现;产NIV的亚洲镰刀菌对水稻的致病性要显著高于产3ADON的亚洲镰刀菌。不同产毒化学型亚洲镰刀菌对水稻均有一定致病性,但NIV化学型亚洲镰刀菌对水稻的致病力最强。

To clarify the composition and pathogenicity of Fusarium species isolated from Fusarium head blight of rice,341 rice samples were collected from 41 counties of 13 cities in 2018 and 2019 in Jiangsu Province.Fusarium isolates were identified with molecular method based on the translation elongation factor 1α(TEF-1α)gene sequence.According to TRI11 gene sequences and in-vitro toxin production,the chemotype of F.graminearum species complex was determined.Then,to complete Koch’s postulate,the F.asiaticum isolates in different chemotypes were tested for pathogenicity.The results showed that a total of 392 isolates were obtained from rice samples,including F.asiaticum(n=385)and F.graminearum(n=7).Of them,66.8%of F.asiaticum isolates were the 3-acetyldeoxynivalenol(3ADON)chemotype and the remainders were the nivalenol(NIV)chemotype.In addition,all the F.graminearum isolates were the 15-acetyldeoxynivalenol(15ADON)chemotype.Moreover,F.asiaticum with 3ADON chemotype was dominant in Jiangsu Province,while 15ADON chemotype of F.graminearum strains could only be found in the northern Jiangsu.The results of pathogenicity test showed that F.asiaticum isolates in the NIV chemotype were more virulent to rice than F.asiaticum isolates in 3ADON chemotype.Generally,F.asiaticum isolates in NIV chemotype had the strongest pathogenicity against rice,but variation existed within chemotypes of F.asiaticum.