植物病原菌拮抗性野生艾蒿内生菌的分离、筛选和鉴定

Isolation,screening and characterization of phytopathogen antagonistic endophytes from wild Artemisia argyi

从野生艾蒿的根茎叶部位分离出内生细菌共68株,以棉花枯萎病、稻瘟病、烟草赤星为供试病原菌,采用对峙法对内生菌分别进行抑菌试验,对筛选出的菌株进行了16S rDNA序列测定和系统发育分析。结果表明:从野生艾蒿分离到的内生菌经初筛、复筛,获得抑制病原菌效果最明显的3株菌,结合生理生化特性、菌落特征、细胞形态特征和16S rDNA测序分析结果,菌株L8、S11和R6分别鉴定为Bacillus subtilis,Bacillus cereus,Paenibacillus polymyxa。拮抗实验表明,棉花枯萎病原菌菌丝发生弯曲、打结,烟草赤星的受作用菌丝生长端分枝明显增多,生长端边缘呈珊瑚状分枝,并且出现明显的畸形和萎缩现象。分析表明,可能是由于在培养过程中内生菌产生了化感物质,对病原菌的菌丝产生抑制作用的结果。

A total of 68 endophytes isolated from roots, stems and leaves of wild Artemisia argyi were used to study antagonistic effect against phytopathogens including Fusarium oxysporum, Magnaporthe grisea and Alternaria alternate, and characterized by 16S rDNA sequencing and phylogenies. The results indicated that three of the endophytes have the most obvious inhibitory effect by the first and the second screening. Combined with the physiological and biochemical characteristics, colony characteristics, cell morphological characteristics and 16S rDNA sequencing results, the three strains L8, S11 and R6 were identified as Bacillus subtilis, Bacillus cereus, Paenibacillus polymyxa, respectively. Antagonistic experiment showed that hyphae of Fusarium oxysporum became bending and knot while hyphae of Alternaria alternata grew more branches. The growth end appeared coralline branch with deformity and atrophy, suggesting that allelochemicals produced by endophytes in the development process, might be inhibit the development of pathogens hyphae.