水稻稻瘟病生防菌筛选、鉴定及作用机制初探

Screening,Identification and Mechanism of Biological Control Strain Against Magnaporthe oryzae

为研究生防菌对稻瘟菌的抑制作用,采用平板对峙法从人参根际土壤中筛选出对稻瘟菌具有抑制作用的菌株3株。利用生理生化特征及16S rDNA序列分析将其中一株抑菌效果最好的菌株GS-1鉴定为贝莱斯芽孢杆菌(Bacillus velezensis)。抑菌谱测定结果表明,生防菌GS-1对稻瘟菌(Magnaporthe oryzae)、禾谷镰孢菌(Fusarium graminearum)、立枯丝核菌(Rhizoctonia solani)、玉米大斑病菌(Setosphaeria turcica)、核盘菌(Sclerotinias sclerotiorum)和灰葡萄孢菌(Botrytis cinerea)均有一定抑制作用。其发酵液对稻瘟菌的抑制率达90%以上,发酵液正丁醇粗提物对稻瘟菌的抑制率达到57%。通过电导率测定,发现GS-1可显著提高稻瘟菌的细胞膜渗透性,影响细胞内离子稳态。且经GS-1处理的稻瘟菌菌丝的脂质过氧化程度显著升高,说明GS-1对稻瘟菌具有较好的抑制潜力,为下一步开发防治稻瘟病的微生物菌剂奠定了基础。

To investigate the inhibitory effect of biocontrol agent against Magnaporthe oryzae,3 biocontrol fungi which have obvious antifungal effect were screened out from rhizosphere of Ginseng with plate-screening method.The strain GS-1,which exhibited the best antifungal performance,was identified as Bacillus velezensis based on physiological and biochemical characteristics,as well as 16S rDNA sequence analysis.The antifungal spectrum showed that biocontrol bacterium GS-1 demonstrated a degree of inhibitory activity against M.oryzae,Fusarium graminearum,Rhizoctonia solani,Setosphaeria turcica,Sclerotinias sclerotiorum and Botrytis cinerea,respectively.The inhibitory rate of GS-1 fermentation broth and n-butyl alcohol extract to M.oryzae was 90%and 57%,respectively.The conductivity and MDA content of M.oryzae was significantly increased under GS-1 treatment,so GS-1 would be a potential biocontrol strain against rice blast,which laid a basis for the development of a microbial agent to control rice blast disease in future studies.