委内瑞拉链霉菌RL-2活性产物对植物病原真菌的抑制作用及其作用机制

Inhibitory effect and mechanism of Streptomyces venezuelaevar RL-2 active products on plant pathogenic fungi

为了探明委内瑞拉链霉菌RL-2在植物病害生物防治中的应用价值,在离体条件下采用生长速率法、活体条件下采用盆栽法研究了RL-2活性产物对多种植物病原真菌的抑制作用。结果表明:在离体条件下,RL-2活性产物对供试的7种病原真菌均有较强的抑制作用,其中对稻瘟病菌的抑制作用最强,EC50为5.35mg/L;在活体条件下,不仅能阻止专性寄生的黄瓜霜霉病病原菌菌丝入侵,而且对已侵入的菌丝有很好的治疗效果。电镜观察结果显示,RL-2活性产物强烈抑制病原菌菌丝生长和孢子萌发,引起菌丝膨大和畸形、孢子萌发率降低、萌发孢子芽管畸形。此外,经RL-2活性物质处理的病原菌接种寄主植物后,其致病性减弱、病斑扩展减慢。

In order to find out the application value of the Streptomyces venezuelaevar RL-2 for biological control on plant diseases, the inhibitory effect of the active products of RL-2 on plant pathogenic fungi was studied by means of inhibition rate of mycelium growth in vitro and pot tests in vivo, respectively. The results showed that the active products of RL-2 had a strong inhibitory effect on seven tested plant pathogenic fungi in vitro, on among which Phyricularia grisea was the best with the ECs0 was 5.35 mg/L; in vivo conditions, the active products from RL-2 not only prevented the infection of mycelia of post-para- sitic Pseudoperonospora cubensis, but also exhibited a good therapy efficacy to the invaded mycelia. The results from electron microscope observation showed that the active products of RL-2 strongly inhibited the growth of mycelia and spore germination, resulting in the inflated and malformed mycelia, decreased rate of spore germination, and deformed germ tube. In addition, the pathogenicity of mycelia inoculated to host plant developed slowly after treated with RL-2 active products.