一株能拮抗3种土传病害病原真菌的长枝木霉

为了丰富生防木霉菌(Trichodermaspp.)种资源,在园林植物八宝景天(Sedum spectabile)根际土壤中分离得到一株优势木霉。根据该菌株菌落的形态特征、形态学显微观察、菌株rDNA-ITS序列分析以及邻接法同源性比对等结果判定木霉菌株种类。采用平板对峙法将该菌株与3种土传病害病原菌(Sclerotinia sclerotiorum)、立枯丝核菌(Rhizoctonia solani)和细链格孢菌(Alternaria alternata)]进行对峙培养。并用该木霉诱导山新杨(Populus davidiana×P.albavar.Pyramidalis)组培苗,观察离体叶片抵抗细链格孢菌侵染的能力。结果表明,此木霉为长枝木霉(Trichoderma longibrachiatum),命名为Tl-70。该菌株对3种土传病害病原真菌均有较明显的拮抗作用。对核盘菌的抑菌率最高为77.71%,显著高于对细链格孢菌和立枯丝核菌的抑制率(P0.05);对立枯丝核菌的抑菌率为58.56%,显著高于对细链格孢菌的抑制率(P0.05);对细链格孢菌的抑菌率最低,为53.32%。并且,该木霉能提高山新杨组培苗叶片拮抗细链格孢菌侵染的能力。说明此菌株是具有潜力的生防菌株。

A Trichoderma longibrachiatum strain with antagonistic effects against three soil-borne pathogenic fungi

To enrich the microbial resources of Trichoderma spp.for biocontrol, a dominant Trichoderma strain was isolated from the rhizosphere soil of a landscape plant, Sedum spectabile Boreau.The isolated Trichoderma strain was identified using colonial-and micro-morphological observations, ribosomal DNA (rDNA)-internal transcribed spacer (ITS) sequence alignment, and homology analysis using a Neighbour-Joining method.An agar disk diffusion method was used to investigate the antagonism between the isolated Trichoderma strain and three other soil-borne pathogenic fungi, Sclerotinia sclerotiorum, Rhizoctonia solani, and Alternaria alternata.The tissue-cultured plantlets of Populus davidiana×P.alba var.Pyramidalis were further inoculated with the isolated Trichoderma strain and the resistance of the inoculated seedling leaves against A.alternata was evaluated in vitro.The results demonstrated that the isolated Trichoderma strain was Trichoderma longibrachiatum and it exhibited evident and differential antagonistic effects against each of the three tested soil-borne pathogenic fungi.We designated the isolated Trichoderma strain as Tl-70.The antifungal activity of Tl-70 against S.sclerotiorum was a 77.71% inhibition, which was the highest and significantly higher than that against R.solani or A.alternata (P<0.05).The antifungal activity against R.solani was a 58.56% inhibition, and significantly higher than that against A.alternata (P<0.05, 53.32%), which was the lowest of the three tested strains.Moreover, inoculation with Tl-70 enhanced the disease resistance of the leaves of tissue-cultured Populus davidiana×P.alba var.Pyramidalis seedlings against the pathogen A.alternata.Our results suggest that Tl-70 is a potential biocontrol strain.