蔬菜根结线虫生防放线菌LY4的筛选及其鉴定

Screening and Identification of Biocontrol Atinomycetes spp.LY4 against Meloidogyne incognita

【目的】植物根结线虫是一种重要的植物病原生物,每年都会给世界农业带来巨大的经济损失,为能够有效地控制根结线虫对植物所带来的危害以及化学类农药的滥用对环境、人畜所带来的危害,探索利用新的天然微生物资源来进行病虫害防治途径愈显重要。【方法】试验从云南农业大学农场、昆明捞鱼河湿地公园、云南省陆良县等地采集土样、分离得到101株放线菌,通过其发酵液上清液原液和不同浓度的发酵液上清液杀线活性试验以及土壤稳定性试验进一步筛选出具有高效稳定的杀线潜力菌株,结合生理生化鉴定和16S rDNA分子鉴定对高效菌株进行鉴定。【结果】101株放线菌发酵上清液原液处理南方根结线虫二龄幼虫24 h后初筛得到3株防效高于90%的菌株LY4、LY8和GT6,菌株发酵上清液原液稀释2倍和5倍的条件下处理南方根结线虫72 h的校正死亡率分别为99.64%、98.67%、100.00%和78.85%、73.16%、92.60%,采用小盆栽试验对3株生防放线菌发酵液原液进行稳定性防效试验,经发酵液原液灌根处理30 d后,3株生防放线菌都具有对南方根结线虫的杀伤活性,菌株LY4、LY8、GT6的防效分别是71.10%、57.78%、40.00%。结合菌株LY4的形态特征、生理生化鉴定及16S rDNA鉴定了放线菌菌株LY4的归属种类,初步将菌株LY4鉴定为淡紫灰链霉菌(Streptomyces lavendulae)。【结论】放线菌菌株LY4对南方根结线虫具有较好的抑制效果,有潜在生防价值。

[Objective]Plant root-knot nematode is an important plant pathogenic organism,which brings huge economic losses to world agriculture every year.In order to effectively control the harm of root-knot nematode to plants and the harm of chemical pesticides to environment,people and animals,it is increasingly important to explore new natural microbial resources for biological control of diseases and insect pests.[Method]In this experiment,101 strains of actinomycetes were collected from the farm of Yunnan Agricultural University,Laoyuhe Wetland Park in Kunming,Luliangcounty in Yunnan Province,etc.The strains with high efficiency and stable killing potential were further screened through the supernatant liquid of fermentation liquor,different concentration supernatant of fermentation liquor killing activity test and soil stability test.The high efficiency strains were identified by physiological and biochemical identification and 16S rDNA molecular identification.[Result]Three strains LY4,LY8 and GT6 with control efficiency higher than 90%were screened after 101 strains of actinomycetes fermentation supernatant liquid treated the second instar larvae of Meloidogyne incognita for 24 hours.The corrected mortality rates of 72 hours treated with fermentation supernatant liquid diluted twice and five times were 99.64%,98.67%,100.00%and 78.85%,73.16%,respectively Through the soil stability test,the stability and control effect of the three strains of biocontrol actinomycetes fermentation broth were tested by pot experiment.The results showed that after 30 days of root irrigation treatment,all the three strains of biocontrol actinomycetes had killing activity against Meloidogyne incognita,and the control effects of strains LY4,LY8 and GT6 were 71.10%,57.78%and 40.00%,respectively.Combined with morphological characteristics,physiological and biochemical identification and 16S rDNA molecule,the genus of actinomycete strain LY4 was identified,and the strain LY4 was preliminarily identified as streptomyces lilacinus.[Conclusion]Actinomycete strain LY4 has a good inhibitory effect on Meloidogyne incognita and has potential biocontrol value.