茶叶斑病病原菌茶拟盘多毛孢(Pseudopestalotiopsis theae)鉴定及生物学特性

Identification and biological characteristics of Pseudopestalotiopsis theae,an important pathogenic fungus causing tea leaf spot

从贵州省开阳县茶树叶部病害样品中分离纯化多个形态相似分离物,对其进行了菌落形态、子实体、产孢细胞和分生孢子等形态观察。依据内转录间隔区、部分28s大亚单位rDNA、翻译延伸因子1-α和微管蛋白基因,采用PAUP软件及最大简约法,进行了多基因系统发育树分析。在室内和自然条件下研究了代表性菌株AXLKY2019015对茶树叶片的致病性以及不同温度和pH等条件下该菌株的生长情况。结果表明,代表性菌株AXLKY2019015的菌落形态、子实体、产孢细胞和分生孢子等形态与茶拟盘多毛孢(Pseudopestalotiopsis theae)一致。多基因系统发育树分析表明,AXLKY2019015菌株与茶拟盘多毛孢(Ps.theae)的模式菌株MFLUCC12-0055在系统发育树上聚为一支,其自举支持率为100%。因此,初步确认菌株AXLKY2019015属于茶拟盘多毛孢(Ps.theae)。生物学特性研究表明,AXLKY2019015菌株在PDA培养基上生长最快,生长速率为(1.1728±0.0156)cm/d,显著高于OA和MEA培养基;在PDA培养基上最适生长温度为28℃,最适p H为7.0。致病性分析表明,AXLKY2019015菌株可在室内和自然条件下引起福鼎大白茶叶部产生病斑,符合柯赫氏法则。

To effectively control the tea leaf spot in K aiyang County,Guizhou Province,we isolated many isolates with similar morphology,and observed the morphology of their colonies,sporocarps,conidiogenous cells and conidia in this study.The phylogenetic analysis was conducted by PAUP software with the method of Maximum parsimony based on multi-locus sequences of ITS,LSU,TEF1-αand TU B-2 b.According to Koch′s rule,the pathogenicity of the isolate AXLKY2019015 on tea leaves was tested under both laboratory and natural conditions.The growth of the isolate AXLKY2019015 was studied under different medium,temperature as well as pH conditions.Our study showed the following results:①The morphology of the isolate AXLKY2019015 was similar to Pseudopestalotiopsis theae in terms of colony,sporocarp,conidiogenous cell and conidium.The phylogenetic analysis showed that the isolate AXLKY2019015 was clustered into the clade that reference isolate MFLUCC12-0055 Pseudopestalotiopsis theae was located,with a bootstrap level of 100%.These results suggested our isolate AXLKY2019015 was identified as Ps.theae.②The biological characteristics showed that the isolate AXLKY2019015 grew fastest on PDA with a growth rate of(1.1728±0.0156)cm/d,which was significantly higher than that on OA and MEA.Its optimum growth temperature on PDA medium was 28 oC,and the optimum growth pH was 7.0.③The pathogenicity analysis showed that the isolate AXLKY2019015 could cause the same tea leaf spot under both laboratory and natural conditions,which was in accord with Koch′s rule.