1株新疆胡杨林昆虫病原线虫鉴定及生物学特性

【目的】对新疆天然胡杨林中昆虫病原线虫(EPNs)进行分离、鉴定并测试其杀虫活性,为胡杨林害虫生物防治提供新的选择。为新疆天然胡杨林中EPNs资源挖掘和基于EPNs的胡杨林害虫生物防治提供资源储备和奠定研究基础。【方法】利用经典方法,诱导及富集EPNs、分子生物学与形态学相结合鉴定,以及不同剂量杀虫测试分析其种属及生物学特性。【结果】在新疆天然胡杨林中存在EPNs,采集地检出率达25%。线虫18S rDNA系统发育树分析其在进化关系上与Steinernema litorale strain Pak.S.P.7 进化关系最近,获得基因登录号No: MK416208;形态学表明其与Steinernema litorale模式株大部分特征值基本吻合,主要区别在于第1代雄虫:体长略长(1 461.01 μm)、排泄孔至头部距离短(86.98 μm)、交合刺短(69.49 μm)、D%(60.45)与SW%158.21 值小于模式株;侵染期幼虫:体长(885.88 μm)和尾长(74.81 μm)短、E%(83.88)值大。共生细菌16S rDNA系统发育树分析与Xenorhabdus bovienii strain Zakharovo 的进化距离最近。杀虫分析表明,在160IJs/Gm (Galleria mellonella) 及其以上处理组36 h之内校正致死率达到100%;对黄粉虫60 h内40IJs/Tm (Tenebrio molitor) 及以上剂量校正致死率超过50%,160IJs/Tm及以上试验组校正致死率超过75%。【结论】在新疆天然胡杨林中发现有EPNs的分布,Steinernema litorale 在采集地是优势种,同时其具有较强的杀虫能力。

Research on Steinernema litorale from Populus euphratica Forest in Xinjiang by Identification and Biological Characteristics

【Objective】 The purpose of this research was to isolate, identify the species of Entomopathogenic nematodes in natural Populus euphratica forests in Xinjiang and test its insecticidal activity in the hope of providing a new choice for biological control of the insects. 【Method】 The EPNs were induced by Galleria mellonella and collected with white-trap method, and then identified with molecular and morphology and finally biological characteristics were tested by different dosages of EPNs to Galleria mellonella (Gm) and Tenebrio molitor (Tm). 【Results】 The results showed that EPNs existed in natural Populus euphratica forests in Xinjiang, and the detection rate was up to 25%. The phylogenetic analysis of 18S rDNA showed that it had the closest evolutionary relationship with Steinernema litorale strain Pak.S.P.7, and the obtained Genebank accession No was: MK416208. Morphological analysis showed that most of the eigenvalues of Steinernema litorale - Bachu were almost the same with the Steinernema litorale type strain, but the main differences were that: compared to the type strain, the length (1461.01 μm) of first generation male was slightly longer, the distance from anterior end to excretory pore (86.98 μm) was shorter, the spicule length (69.49 μm) was shorter, values of D% (60.45) and SW% (158.21) were lower; Compared to the type strain, the length (885.88 μm) of infective juveniles and tail were shorter. The phylogenetic analysis of 16S rDNA of symbiotic bacteria was the closest to Xenorhabdus bovienii strain Zakharovos. The insecticidal analysis of infective juveniles showed that the mortality was 100% within 36 hours in 160 IJs/Gm and above treatment groups. Mortality was 50% in 40 IJs/Tm and 75% in 160 IJs/Tm and above treatment groups for Tenebrio molitor within 60 hours. 【Conclusion】 The research first discovered the distribution of EPNs (Steinerma litorale) in natural Populus euphratica forest in Xinjiang, and it has high insecticidal activity. This will provide a resource reserve and research foundation for the exploitation of EPNs resources in natural Populus euphratica forests and the biological control of pests in Populus euphratica forests based on EPNs in Xinjiang in the future.