The Streptomyces spp. used in this work were previously isolated as diazotrophic endophytes from sorghum stems. Here, we characterized the Streptomyces spp. for their colonization ability, plant growth promotion and protection against fungal disease in three cereals. In vitro analysis by dual culture study showed inhibitory effect on the rice pathogen Magnaporthe oryzae B157 along with inhibition of the ubiquitous phytopathogen Rhizoctonia solani by the Streptomyces spp. used in this study. The active compounds responsible for phytopathogen inhibition were extracted with ethyl acetate and tested positive against the fungal pathogens. GC–MS based identification of the active compounds responsible for fungal pathogen inhibition showed them to be 2-(chloromethyl)-2-cyclopropyloxirane, 2, 4- ditert-butylphenol and 1‐ethylthio‐3‐methyl‐1, 3‐butadiene in extracts of culture supernatants from the three different strains respectively. EGFP tagged Streptomyces strains showed profuse colonization in roots as well as aerial parts of cereal plants. Direct inhibitory action against M. oryzae B157 and R. solani correlated with the observation that upon fungal pathogen challenge, the bacterized rice, sorghum and wheat plants showed significantly good plant growth, particularly in aerial parts as compared to unbacterized controls. In addition, benefit was seen in inoculated healthy plants in terms of increase in wet weight of roots and shoots as compared to the uninoculated controls. The mechanism of biocontrol also involved induction of plant defense response as evidenced by the upregulation of PR10a, NPR1, PAL and LOX2 in Streptomyces colonized plants.

在链霉菌属。先前从高粱茎中分离出重氮营养内生菌用于这项工作。在这里，我们表征了链霉菌属。在三种谷物中具有很强的定植能力，促进植物生长和防止真菌病的作用。双重培养研究的体外分析表明，链霉菌对水稻病原体稻瘟病菌（Magnaporthe oryzae） B157具有抑制作用，并且对普遍存在的植物病原菌根瘤菌（Rhizoctonia solani）具有抑制作用。spp。在这项研究中使用。用乙酸乙酯提取负责抑制植物病原体的活性化合物，并经测试对真菌病原体呈阳性反应。基于GC-MS的鉴定方法可识别引起真菌病原体抑制的活性化合物，表明它们为2-（氯甲基）-2-环丙基环氧乙烷，2,4-二叔丁基苯酚和1-乙基硫代-3-甲基-1、3-丁二烯。分别来自三种不同菌株的培养上清液的提取物。EGFP标记的链霉菌菌株在谷物植物的根部和空中部分均显示出大量定殖。对米曲霉B157和茄形梭菌的直接抑制作用与观察到的相关性相关，即在真菌病原体攻击后，与未细菌的对照相比，已细菌化的水稻，高粱和小麦植物显示出明显良好的植物生长，特别是在空中部分。另外，与未接种的对照相比，在接种的健康植物中根和芽的湿重增加方面看到了益处。生物防治的机制也植物防御反应的诱导参与作为证明的上调PR10a，NPR1，PAL和LOX2在链霉菌定植植物。