荷兰进境铃兰苗中铃兰短体线虫的鉴定

Identification of Pratylenchus convallariae intercepted in seedlings of Convallaria majalis from Netherlands

[目的]为了控制检疫性线虫的传入,保障我国花卉苗木产业健康发展,本文对云南口岸进境的荷兰铃兰苗(Convallaria majalis)中截获的一种短体属线虫(Pratylenchus sp.)进行了形态学特征鉴定和分子序列分析,为进出境植物线虫检疫鉴定提供参考依据。[方法]通过形态特征观察、形态特征测计值比较,以及基于rDNA28S-D2/D3区序列构建短体属线虫群体系统进化树的方法,对截获的荷兰线虫群体进行种类鉴定。[结果]截获的荷兰线虫群体形态学和分子生物学特征与铃兰短体线虫(P.convallariae)相似,其主要形态特征为:唇区略缢缩,唇环3个;口针粗壮,长15~17μm,基部球呈郁金香球状;受精囊近球形至矩形,内部充满精子;后阴子宫囊长20.0~29.0μm;尾端略平截、粗糙,或常有不规则环纹。系统进化树揭示:该截获群体与铃兰短体线虫美国群体、比利时群体和法国群体聚类形成1个独立分支,序列相似性达98.0%~100%;而穿刺线虫组的其他成员,包括沙丘短体线虫(P.dunensis)、伪短体线虫(P.fallax)、油橄榄短体线虫(P.oleae)、穿刺短体线虫(P.penetrans)和肥尾短体线虫(P.pinguicaudatus),则各自形成了单独的分支。[结论]根据形态学和分子特征分析将截获的荷兰线虫群体鉴定为铃兰短体线虫,我国口岸检疫部门应加强检疫监管,降低该线虫传入的概率。

[Objectives] In order to control the introduction of quarantine nematodes and ensure the healthy development of the flower and seedling industry in China,a Pratylenchus population intercepted at Yunnan Port,China and isolated from seedlings of Convallaria majalis imported from Netherlands,was morphologically and molecularly identified.The study will provide theoretical support for nematode identification by Chinese plant quarantine services.[Methods] The intercepted population was identified using the morphological observation,the morphometric comparison and the phylogenetic analysis of Pratylenchus species based on sequences of 28S D2/D3 region of rDNA.[Results] The morphological and molecular characterizations revealed that the intercepted Dutch population were similar to P.convallariae.The morphological characters of the population were mainly as follows:labial region slightly offset from body,bearing three annuli;stylet stout with knob tulip-shaped,15-17 μm long;spermatheca rounded to spherical or rectangular,and the interior filled with sperm;post-vulval uterine sac 20.0-29.0 μm long;tail tip truncate,coarsely and often irregularly annulated.The phylogenetic analyses revealed that the intercepted population formed an independent branch with the American,Belgian and French populations of P.convallariae,with a sequence similarity of 98.0%-100%.The other members in the Penetrans group,including P.dunensis,P.fallax,P.oleae,P.penetrans and P.pinguicaudatus,each formed an independent branch.[Conclusions] The intercepted population from Netherlands was identified as P.convallariae based on morphological and molecular analyses.The quarantine bureaus in Chinese Ports should strengthen the supervision of P.convallariae to reduce the probability of the introduction into China.