植物内生放线菌FQ-017对番茄苗期灰霉和叶霉病的防治作用

A Plant Endophytic Actinomycetes,Streptomyces griseus FQ-017,Its Antifungal Activity against Botrytis cinerea and Fulvia fulva on Tomato

为了在番茄内生放线菌总类群中识别目的放线菌,筛选出了5株FQ-017抗代森锰锌菌株,选择保持原菌株抑菌能力的抗性突变菌株FQ-017-3作为定殖及温室盆栽防效试验的菌株。灌根法接种并重新分离结果显示,茎中内生放线菌带菌量最高,根中次之,叶片中最低。各组织带菌量在体内呈现了高→低→高→低的趋势,第35天仍能从各组织中分离到FQ-017-3,表明FQ-017-3不仅能够长时间定殖于番茄体内而且能够增殖。温室盆栽试验结果表明,接种内生菌FQ-017于番茄苗22 d和32 d后对番茄灰霉病的平均相对防效分别为56.26%和58.25%,两者基本相当,对番茄叶霉病的平均相对防效分别为58.09%和23.96%,FQ-017-3对叶霉病的防效在后期明显降低,说明该菌对不同病原菌的防治效果不同。根据16S rRNA序列分析结果和培养形态特征,确定FQ-017为灰色链霉菌Streptomyces griseus。

FQ-017 is one of the endophytic actinomycetes isolated from tomato. In order to recognize and to assure its colonization ability, mancozeb used as a challenge agent to induce some stable mutant strains. Re-inoculating FQ-017-3 that kept the wild strain antifungal activity on tomato seedlings by irrigating. The re-solated result transformed by colony forming units per gram indicated that CFU/g in stem on five isolated times are more than that of roots and leaves. The amount of actionmyces in each organ showed curving line that took high then low and high again and low again. However, FQ- 017-3 could be re-isolated even after inoculating 35 days. This colonization and multiplication ability is benefit to control diseases on tomato. FQ-017 used for further greenhouse test against two fungal diseases on tomato caused by Botrytis cinerea and Fulvia fulva. In both treatments, the average effect control against B. c inerea can reach 56.26% and 58. 25%, there were no discrepancy between the two, and the average effect control against F. fulva can reach 58.09% and 23.96%, the latter is less than the former greatly. That is to say, the controlling effects for these two fungal diseases were different. The present research results assured that isolate FQ-017 was suitable candidate for the biocontrol of two talked-about main fungal diseases on tomato. FQ-017 was identified as Streptornyces gri- seus based on the analysis of its 16S rRNA sequences and colony morphological characteristics on several media.