放线菌JS2对石榴枯萎病菌及南方根结线虫的毒力研究

Studies on the Toxicity of Actinomycete JS2 to Pomegranate Wilt Pathogen and Root Knot Nematode

石榴枯萎病是一种比较难防治的土传病害,石榴根结线虫病的广泛发生加重了石榴枯萎病发生程度及病害的防控难度,所以探索兼具拮抗石榴枯萎病及根结线虫病的生防菌,才能有效环保地控制石榴枯萎病。首次报道了链霉菌JS2兼有拮抗石榴枯萎病菌及抑杀南方根结线虫的活性。本研究从云南蒙自、建水石榴园采集的土样中分离筛选得到对石榴枯萎病菌有较强拮抗活性的放线菌,其中菌株JS2对石榴枯萎病菌的室内抑菌直径为3.5 mm。研究结果表明菌株JS2对南方根结线虫有较好的抑杀作用,50%JS2菌悬上清液处理南方根结线虫卵6 d的孵化率与对照相比降低了53.33%,50%JS2菌悬上清液处理南方根结线虫二龄幼虫72 h后,校正死亡率增加了83.88%。菌株JS2兼有拮抗石榴枯萎病菌及抑杀南方根结线虫的活性,具有潜在生防价值。结合菌株JS2在各鉴定培养基上的培养特征、形态学观察及16S rD NA序列分析,将JS2初步鉴定为公牛链霉菌(Streptomyces tauricus)。

Pomegranate wilt disease is a kind of soil borne disease and very difficult to control,and pomegranate root knot nematode disease occurs widely,which aggravate the pomegranate wilt disease results in more difficult control.Therefore,exploring bio-control bacteria with antagonism against pomegranate wilt disease and root knot nematodes is an environmental-friendly method to control pomegranate wilt disease.The finding of this study is the first report of Streptomyces tauricus antagonism to pomegranate wilt pathogen and toxicity to Meloidogyne incongnita.This study was conducted by separating actinomycetes which have strong antagonism activity to pomegranate wilt pathogen from the soil collected from Mengzi po- megranate garden,Mengzi County and Jianshui po-megranate garden,Jianshui County in Yunnan Province.The indoor bacteriostatic diameter of actinomycetes strains JS2 to pomegranate wilt pathogen was 3. 5mm. The finding showed that actinomycete strain JS2 fermented liquid inhibited the batch of M. incongnita eggs and had toxicity to M. incongnita second-stage juveniles.Compared with the control,the hatching rate of M. incongnita was lowered down by 53.33% by dealing with 50% JS2 supernatant fermented liquid 6 d,and the corrected mortality rate of M. incongnita secondstage juveniles increased by 83.88% by dealing with 50% JS2 supernatant fermented liquid for 72 h,which implies the potential bio-control value of strain JS2 in control pomegranate wilt disease.Besides,strain JS2 could be identified as S. tauricus based on its growth characteristics,morphological characteristics and analysis of16 sr DNA sequence.