过路黄叶斑病病原鉴定及拮抗细菌的筛选

Pathogen Indentification of Lysimachia christinae Leaf Sopt and Screening of Antagonistic Bacterial Strains

为明确贵州省施秉县过路黄叶斑病的病原种类,探索该病害的生物防治方法,本试验利用组织分离法、致病性测定法获得致病菌株GLHYB,并结合形态学特征和基于内转录间隔(ITS)、β-微管蛋白(β-tubulin)、延伸因子(EF-1α)3个基因构建系统发育树,将该菌株鉴定为腐皮镰刀菌(Fusarium solani)。利用组织块培养法、平板对峙法从太子参(Pseudostellaria heterophylla)健康块根内分离筛选出1株对F.solani抑菌率达50%以上的拮抗细菌X14,根据生理生化特性及16S rDNA、促旋酶(gyrAse)A亚单位基因序列分析,将X14鉴定为枯草芽孢杆菌(Bacillus subtilis)。该菌株能引起F.solani菌丝畸形和膨大,且具有广谱抑菌性,对4种供试病原真菌的抑菌率为50%~70%。本研究为防治镰刀菌属引起的过路黄叶斑类病害提供了生物材料及理论参考。

In order to identify the pathogen of Lysimachia Christinae caused leaf spot in Shibing County of Guizhou Province and explore the biological resources to control this disease,the pathogenic strain GLHYB was separated and identified by tissue separation and pathogenicity test.Combined with morphology and the sequence analysis of internal transcribed spacer(ITS),β-tubulin and elongation factor(EF-1α),the strain was identified as Fusarium solani.To control this disease,an antagonistic bacteria strain X14,with 50%inhibition rate against F.solani,was isolated from the healthy root tuber of Pseudostellaria heterophylla by tissue block culture and flat plate confrontation methods.Subsequently,the X14 was identified as Bacillus subtilis according to its physiological,biochemical characteristics and the sequences of 16S rDNA and gyrA genes.X14 could result in the mycelium deformity and expansion of F.solani,showed broad-spectrum antibacterial activity against four tested pathogenic fungi with the inhibition rate between 50%and 70%.This study provides a potential bacteria for biological control of leaf spot in Lysimachia Christinae.