生物多样性 ›› 2010, Vol. 18 ›› Issue (2): 120-128.DOI: 10.3724/SP.J.1003.2010.125

• 论文 • 上一篇    下一篇

利用EST-SSR分子标记检测鹅掌楸种间渐渗杂交

张红莲; 李火根*   

  1. 南京林业大学林木遗传与生物技术省部共建教育部重点实验室, 南京 210037
  • 收稿日期:2009-09-25 出版日期:2010-03-20 发布日期:2010-03-20
  • 通讯作者: 李火根

Detection of interspecific introgressive hybridization in Liriodendron with EST-SSR markers

Honglian Zhang; Huogen Li*   

  1. Key Laboratory of Genetics & Biotechnology, Nanjing Forestry University, Ministry of Education, Nanjing 210037
  • Received:2009-09-25 Online:2010-03-20 Published:2010-03-20
  • Contact: Huogen Li

摘要:

引进物种常与本土近缘种间发生杂交而导致基因渐渗, 进而影响本地种的遗传系统。鹅掌楸(Liriodendron chinense)为我国濒危树种之一, 鹅掌楸种间杂交可配性高, 近10年来随着北美鹅掌楸(L. tulipifera)的大量引种及杂交鹅掌楸的繁殖推广, 鹅掌楸种间发生基因渐渗的可能性大大增加。本文以5个包含鹅掌楸、北美鹅掌楸、杂交鹅掌楸的人工混交林为实验群体, 每个群体包含19–130个成年个体及60–117个自然更新小苗或半同胞子代, 利用EST-SSR(simple sequence repeat based on expressed sequence tag)分子标记对各子代群体进行亲本分析, 探究鹅掌楸种间自然交配方式以检测鹅掌楸种间渐渗杂交; 同时, 以亲子群体等位基因频率的回归系数作为渐渗系数, 定量分析鹅掌楸属种间基因渐渗。结果表明: 在研究的5个鹅掌楸混生群体中, 均检测到种间渐渗杂交, 且渐渗杂交的方向与效应大小在不同群体间有差异。研究还发现, 各树种基因渐渗程度与其种群个体数有关, 种群个体数越多, 其渐渗能力越强。据此, 我们还探讨了鹅掌楸种质资源保护策略。

Abstract:

Gene introgression usually results from spontaneous hybridization among closely related exotic and native species, and thus can significantly impact the genetic structure of native species, especially on en-dangered species. It is believed that no interspecies reproductive barriers exist within Liriodendron spp. The endangered status of Liriodendron chinense in China is compounded by the potential risk of interspecific in-trogressive hybridization resulting from the frequent introduction of L. tulipifera and by the extensive plant-ing of hybrid Liriodendron within the past decade. Here, we report a possible trend of interspecific introgres-sive hybridization in the genus Liriodendron. We sampled five mixture plantations with L. chinense, L. tuli-pifera, and hybrid Liriodendron from southeastern China. In each plantation, 19–130 adults and 60–117 na-turally regenerated seedlings or open-pollinated progeny were sampled. The mating pattern of Liriodendron was examined using parentage analysis based on 11 EST-SSR loci, and the extent of introgressive hybridiza-tion was estimated in terms of an introgression coefficient derived from parentage-offspring regression coef-ficients of allele frequencies. We found evidence of interspecific introgressive hybridization in all five planta-tions of Liriodendron, although the orientation and extent of gene introgression differed among plantations. Furthermore, for any species, we found that the extent of gene introgression was positively related to its pop-ulation size. Herein, we present conservation strategies for Liriodendron chinense in the context of our re-sults.