黄精根腐病分离菌及其拮抗内生细菌的鉴定

Identification of isolated fungus from root rot of Polygonatum sibiricum and its antagonistic endophytic bacteria

黄精是重要的药食同源植物。采集湖南洪江市发生的黄精根腐病株,从其分离菌株HF2的培养性状和形态学特征、真菌r DNA内转录区(ITS)、EF-1a区序列分析和系统发育关系比较等方面对该菌株进行了鉴定;通过平板对峙试验筛选对黄精根腐病菌具有抑制作用的内生细菌,并进行形态观察、生理生化指标测定和16S rRNA序列分析。结果表明:从根腐病株中分离得到的菌株为尖孢镰刀菌(Fusarium oxysporum);从黄精中分离获得40株内生细菌,对尖孢镰刀菌有抑制作用的菌株10株,其中A8的抑菌效果最好,对病原菌的抑菌圈半径可达13 mm,经鉴定为枯草芽孢杆菌(Bacillus subtilis)。

Polygonatum sibiricum is a medicinal and food plant in China.The strain HF2,isolated from root rot of Polygonatum sibiricum in Hongjiang City,was classified and identified by morphological characteristics,ribosomal DNA(rDNA)internal transcribed spacer(ITS),EF-1a sequence analysis and its phylogenetic relationships with other species of the genus Fusarium.Bacteria were screened from endophytic resources of P.sibiricum against the strain HF2,and were identified by the characteristics of morphology,16S rRNA sequence analysis and physiology and biochemistry tests.The results showed the strain HF2 was identified as Fusarium oxysporum.Of 40 endophytic bacterial strains isolated,ten strains exhibited good inhibition activity against F.oxysporum in vitro,and the strain A8 showed the highest antifungal activity with inhibition zone of 13 mm.The strain A8 was identified as Bacillus subtilis.