茶叶斑病病原菌高粱附球菌(Epicoccum sorghinum)的鉴定及生物学特性

Identification and Biological Characteristics of Epicoccum sorghinum,pathogen of Tea Leaf Spot

为有效控制贵州省独山县茶叶斑病的发生与危害,本文研究了该区域茶叶斑病的病原和生物学特性。结果表明,从该地区茶叶斑病组织中分离的代表性菌株GZDS2018BXT10的菌落形态、分生孢子器、分生孢子和厚垣孢子等形态与高粱附球菌(Epicoccum sorghinum)一致。对ITS、RBP2、TUB、rDNA-LSU核酸或基因进行测序,采用PAUP软件及最大简约法构建多基因系统发育树,结果表明,GZDS2018BXT10菌株与高粱附球菌模式菌株CBS179.80在系统发育树上聚为一支,自举支持率为100%。致病性试验表明,在室内和自然条件下,GZDS2018BXT10菌株可通过损伤方式导致茶树叶部产生病斑,符合柯赫氏法则。因此,确认该区域叶斑病病原为高粱附球菌(E.sorghinum)。菌株可在PDA、OA和MEA培养基上生长,GZDS2018BXT10菌株在OA培养基上生长速率最快,为(0.76±0.01) cm/d,显著高于MEA和PDA培养基(P<0.05),在PDA上最适生长温度为22℃,最适pH为6.0。碳素营养和氮素营养均可影响菌丝的生长。

In order to effectively control the occurrence and damage of tea leaf spot in Dushan County, Guizhou Province, this paper studied the pathogen and biological characteristics of tea leaf spot in the region. The results showed that the colonies, pycnidia, conidia and chlamydospores of the representative strain GZDS2018 BXT10 were identical with the strain Epicoccum sorghinum. The gene or nucleic acid of ITS, RPB2, TUB and LSU were sequenced, then the phylogenetic analysis was conducted by PAUP software with the method of Maximum parsimony based on multi-locus sequences. The strain GZDS2018 BXT10 and E. sorghinum model strain CBS179.80 were grouped together in the phylogenetic tree, and the clade was supported by 100%. The pathogenicity test showed that the strain GZDS2018 BXT10 could induce the lesion on tea leaves using wound mode under the conditions of laboratory and field, in accordance with Koch’s rule. Therefore, the pathogen of tea leaf spot was identified as E. sorghinum. The strain GZDS2018 BXT10 could grow on PDA, OA and MEA medium. The strain GZDS2018 BXT10 grew quickly on OA medium, and the growth rate was(0.76±0.01) cm/d, which was significantly higher than that on MEA and PDA medium(P<0.05). The optimum growth temperature and pH value on PDA medium were 22 ℃ and 6.0. Both carbon and nitrogen nutrition can affect the growth of mycelia.