作物根围土壤木霉菌物种多样性及其体外拮抗病原菌效应

Diversity and Antagonizing Effects of Trichoderma spp. in Crop Rhizosphere Soils

对采自我国西北地区青海、宁夏、甘肃、陕西和新疆农作物根围土壤中的木霉菌进行分离纯化后,采用形态与分子生物学技术进行菌种鉴定,获得14个木霉种属346个菌株。其中哈茨木霉(Trichoderma harzianum)和棘孢木霉(Trichoderma asperellum)为优势菌种,分别占总数的35%和30%;其次为长枝木霉(Trichoderma longibrachiatum)占12%;绿木霉(Trichoderma virens)、深绿木霉(Trichoderma atroviride)、拟康宁木霉(Trichoderma koningiopsis)和平菇木霉(Trichoderma pleurotum)分别占8%,5%,2%和1%;绿色木霉(Trichoderma viride)/钩状木霉(Trichoderma hamatum)和短密木霉(Trichoderma brevicompactum)/矩孢木霉(Trichoderma oblongisporum)分别皆占2%和1%;渐绿木霉(Trichoderma viridescens)、侧耳木霉(Trichoderma pleuroticola)和康宁木霉(Trichoderma koningii)为我国西北地区农作物根围土壤中最小的木霉种群,各仅占0.3%。将纯化的菌株分别与5个靶标病原真菌在马铃薯葡萄糖培养基(PDA)平板上进行拮抗测试,研究结果表明各木霉菌株对病原菌的拮抗效果有明显差异,且其平均拮抗指数均>60%。将2株短密木霉(TR1294&TR1295)进行液体发酵培养,并用稀释5倍的发酵液配制PDA平板,对靶标病原真菌进行抑菌测试。结果显示,这5个病原真菌在含有TR1294和TR1295发酵液PDA平板上的生长抑制率可达72%,表明TR1294和TR1295在液体发酵过程中能产生抑菌次级代谢物。

The isolation and purification of Trichoderma spp. from the crop rhizosphere soils collected from Qinghai, Ningxia, Gansu, Shaanxi ＆ Xinjian in Northwestern China were performed. A total of 346 strains belonging to 14 Trichoderma species were identified by means of morphological and genetical technologies. Among them, Trichoderma harzianum and Trichoderma asperellum are the dominate species, each of them occupies 35% and 30% of the total respectively ; The next one is Trichoderma longibrachiatum, 12%; Trichoderma virens, Tr/choderma atroviride, Trichoderma kortingiopsis and Trichoderma pleurotum occupy 8%, 5%, 2% and 1% respectively; Trichoderma viride/Trichoderma hamatum and Trichoderma brevicompactum/Trichoderma oblongisporum occupy the same of 2% and 1% respectively; Trichoderma viridescerts, Trichoderma pleuroticola and Tri- choderma koningii are the smallest communities in the soils of Northwestern China, they each occupy only 0.3%. All purified stains were individually added onto petri dishes with potato dextrose agar （PDA） to test their antagonistic ability against 5 target pathogens. It was found that the average index of antagonism of the strains is greater than 60% although the antagonistic effect of the strains against the pathogens is obvious different. Liquid fermentation cultures were conducted with 2 strains of Trichoderma brevicompactum （TR1294 ＆ TR1295 ） and the fermented liquids were diluted 5 times to make PDA, on which the target pathogens were individually added to test if the medium can prevent their growth. The results revealed that the medium can prohibit the growth of the pathogens as high as 72%. It means TR1294 and TR1295 produce certain secondary metabolites during fermentation process, which can antagonize the pathogens.