| 齐振华*, 吕 宁, 逄昔莎, 厉 艳, 邵秀玲, 季 蕾.日本进境无花果苗中短颈剑线虫的鉴定[J].植物保护,2024,50(4):211-220. |
| 日本进境无花果苗中短颈剑线虫的鉴定 |
| Identification of Xiphinema brevicollum detected in Ficus carica from Japan |
| 投稿时间：2023-08-18 修订日期：2023-10-07 |
| DOI：10.16688/j.zwbh.2023431 |
| 中文关键词: 短颈剑线虫 寄主 无花果 形态特征 系统发育分析 鉴定 |
| 英文关键词:Xiphinema brevicollum host Ficus carica morphological characteristics phylogenetic analyses identification |
| 基金项目:国家重点研发计划（2021YFD1400100，2021YFD1400103） |
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| 中文摘要: |
| 短颈剑线虫Xiphinema brevicollum是我国重要的检疫性线虫, 寄生于植物根部, 影响寄主植物长势并降低产量。本文对青岛口岸进境的日本无花果Ficus carica苗中截获的一种剑线虫进行了形态学特征鉴定和分子序列分析, 为口岸进境植物线虫检疫提供参考依据。通过形态特征观察、测计, 以及18S rDNA、ITS1、28S-D2/D3区和线粒体COXⅠ基因序列系统发育分析的方法, 对截获的日本无花果线虫种群进行鉴定。截获的日本无花果线虫种群形态学和分子生物学特征与短颈剑线虫相似, 其主要形态特征为:虫体体型中等, 热杀死后向腹面弯曲呈开螺旋“C”形, 体长1 713.4～1 910.2 μm, 最大体宽35.8～47.1 μm, 两端渐细。唇区圆, 缢缩明显, 侧器囊漏斗状。齿尖针约为齿托长度的1.5倍, 齿托基部呈凸缘状;导环为双环;阴门位于虫体中部, 横裂, 阴道长度占阴门处体宽的1/3左右。生殖管对生, 均发育完全, 生殖管较短, 卵巢先端回折, 子宫内无特殊分化。尾短圆锥形, 背面弯曲, 腹面直, 尾尖钝圆, 尾长24.0～29.5 μm, 等于或略长于肛门处体宽。基于rDNA ITS1区构建的系统进化树, 该截获种群与短颈剑线虫巴西种群、新西兰种群、比利时种群及南非种群聚类成一个独立分支, 序列相似性达98.5%～98.7%;基于线粒体COXⅠ序列构建的系统进化树, 该截获种群与短颈剑线虫5个日本种群聚类成一个独立分支, 序列相似性达91.6%～93.6%。根据形态学和分子生物学特征分析, 此次截获的日本无花果线虫种群为短颈剑线虫, 并首次确认了无花果为该线虫的自然寄主, 海关检疫此类苗木进境时应重点关注该线虫, 降低传入几率。 |
| 英文摘要: |
| Xiphinema brevicollum is an important quarantine nematode in China, known to cause damage to its host plants through direct feeding on root tips, typically causing stunted growth and reduced yield. In this study, a Xiphinema species isolated from Japanese fig (Ficus carica) seedlings intercepted at Qingdao Port was morphologically and molecularly identified, providing theoretical support for nematode identification by Chinese plant quarantine services. The intercepted population was identified through morphological observation, morphometric comparison, and phylogenetic analysis based on sequences of the 18S rDNA, ITS1, 28S D2/D3 region, and mitochondrial cytochrome c oxidase subunit I. The morphological and molecular characteristics of the intercepted Japanese fig nematode population closely resemble those of X. brevicollum. Key morphological features included a medium-sized body forming an open spiral “C” shape when heat-relaxed, tapering gradually towards the ends, with a body length ranging from 1 713.4 to 1 910.2 μm, and a body diameter ranging from 35.8 to 47.1 μm. The lip region appeared rounded in lateral view and was offset from the rest of the body, amphidial fovea funnel-shaped. The odontostyle was 1.5 times longer than the odontophore, with well-developed flanges. The reproductive system was didelphic-amphidelphic, with equally developed branches and reflexed ovaries. The vulva was situated at the midbody, forming a transverse slit, with the vagina occupying 1/3 of the corresponding body diameter. The tail was short and conoid, with a prominent dorsal curvature and straight ventral side, with a length of 24.0-29.5μm, equal to or slightly longer than the body diameter at the anus. Phylogenetic analyses based on ITS1 region sequences revealed that the intercepted population formed an independent branch with the populations from Brazil, New Zealand, Belgium, and South Africa, with a sequence similarity of 98.5% to 98.7%. Similarly, phylogenetic analyses based on COXⅠ sequences revealed that the intercepted population formed an independent branch with five Japanese populations of X. brevicollum, with a sequence similarity of 91.6%-93.6%. The intercepted population was identified as X.brevicollum based on morphological and molecular characteristics, marking the first identification of fig as a natural host for X. brevicollum. To minimize the risk of introduction into China, customs quarantine of such seedlings should strengthen the supervision of X. brevicollum. |
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