斑衣蜡蝉若虫寄生蜂地理种群遗传差异及早期快速检测

【目的】明确不同地理种群斑衣蜡蝉Lycorma delicatula若虫寄生蜂种群遗传差异,实现若虫被寄生早期的快速准确检测,以评估其对斑衣蜡蝉种群的控制作用。【方法】利用DNA条形码技术获得不同地理种群斑衣蜡蝉若虫寄生蜂COI和28S rDNA序列,利用K2P模型计算不同地理种群间的遗传距离,以邻接(neighbor-joining,NJ)法构建系统发育树;基于COI序列设计种特异性PCR(SS-PCR)引物,利用SS-PCR对斑衣蜡蝉若虫DNA进行扩增,测定其体内是否有中华螯蜂Dryinus sinicus寄生;利用目测法观察和PCR扩增测定寄生蜂对不同采样点斑衣蜡蝉若虫的寄生率。【结果】经鉴定,不同地理种群斑衣蜡蝉若虫寄生蜂为中华螯蜂,该寄生蜂COI序列共检测到16个单倍型,28S rDNA序列共检测到4个单倍型。不同地理种群间中华螯蜂遗传距离在0.00691~0.01310之间。邻接法构建的系统发育树显示不同地理种群中华螯蜂均聚于一枝。基于COI序列设计的SS-PCR引物对中华螯蜂成虫、幼虫均具有良好的扩增效果,最低检测阈值为0.000005 ng/μL DNA。利用SS-PCR测定中华螯蜂对各采样点斑衣蜡蝉若虫的寄生率为22.54%~60.00%,显著高于目测统计的结果(5.63%~36.98%)。【结论】不同中华螯蜂地理种群间遗传差异较小;SS-PCR引物可用于不同地区中华螯蜂对斑衣蜡蝉早期寄生率的快速检测。

Genetic differences among geographical populations and rapid early detection of a nymphal parasitoid ofLycorma delicatula(Hemiptera: Fulgoridae)

【Aim】 This study aims to determine the genetic differences among parasitoids of Lycorma delicatula nymphs from different geographical populations, and to rapidly identify the parasitism of parasitoids on L. delicatula nymphs at the early parasitization stage so as to evaluate the control effects of parasitoids on L. delicatula populations. 【Methods】 The DNA barcoding method was used to sequence COI and 28S rDNA genes of parasitoids of L. delicatula nymphs from different geographical populations. The genetic distances between the parasitoids from different geographical populations were calculated using K2P model, and a phylogenetic tree was constructed using neighbor-joining (NJ) method. The species-specific PCR (SS-PCR) primers were designed to determine whether L. delicatula was parasitized by Dryinus sinicus by amplification of DNA from L. delicatula nymphs using SS-PCR method. Visual assessment method and SS-PCR amplification were used to determine the parasitism rates of the parasitoids on L. delicatula nymphs from different sampling localities. 【Results】 The parasitoids of L. delicatula nymphs were identified as D. sinicus. A total of 16 haplotypes and four haplotypes were detected in COI and 28S rDNA sequences of D. sinicus from different geographical populations, respectively. The genetic distance among D. sinicus from different geographical populations was 0.00691-0.01310. The phylogenetic tree constructed by NJ method showed that D. sinicus samples from different geographical populations were clustered in one branch. SS-PCR primers based on COI sequence could produce good amplification results for both adult and larva of D. sinicus, with the detection threshold of 0.000005 ng/μL DNA. The parasitism rates of D. sinicus on L. delicatula nymphs from different sampling localities were 22.54%-60.00% detected by SS-PCR, significantly higher than those by visual assessment method (5.63%-36.98%). 【Conclusion】 The genetic differences of D. sinicus from different geographical populations are quite low. SS-PCR primers can be used for rapid detection of the early parasitism of L. delicatula by D. sinicus.