生物多样性 ›› 2019, Vol. 27 ›› Issue (4): 457-467.DOI: 10.17520/biods.2018318

• 综述 • 上一篇    下一篇

榕树种间杂交研究进展

黄建峰1,徐睿2,彭艳琼1,*()   

  1. 1 中国科学院西双版纳热带植物园热带森林生态学重点实验室, 云南勐腊 666303
    2 云南省热带作物科学研究所, 云南景洪 666100
  • 收稿日期:2018-11-27 接受日期:2019-01-31 出版日期:2019-04-20 发布日期:2019-06-05
  • 通讯作者: 彭艳琼
  • 基金资助:
    国家自然科学基金(31800313);国家自然科学基金(31672373);中国科学院"西部之光"人才培养计划项目

Research progress of interspecific hybridization in genus Ficus

Huang Jianfeng1,Xu Rui2,Peng Yanqiong1,*()   

  1. 1 CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303
    2 Yunnan Institute of Tropical Crops, Jinghong, Yunnan 666100
  • Received:2018-11-27 Accepted:2019-01-31 Online:2019-04-20 Published:2019-06-05
  • Contact: Peng Yanqiong

摘要:

杂交是生物进化的重要方式和新物种的重要来源, 在植物界普遍存在, 但在不同植物类群中的发生率差异很大。高度专性传粉体系中, 宿主植物和传粉者经历长期协同进化, 形成远高于其他物种的互利共生机制和合子前生殖壁垒, 被认为不太可能发生种间杂交。榕树和传粉榕小蜂是动植物间专性传粉关系的典范, 甚至发展出一对一高度专性关系。但随着研究的深入, 发现了一定程度的宿主转移现象, 引发学者对榕树种间杂交的研究和探讨。本文从人工杂交、外来种和本地种杂交、岛屿种自然杂交、同域分布近缘种自然杂交, 以及利用系统发育不一致推测杂交等5个方面, 综述了榕树种间杂交的研究进展, 并对未来研究进行展望。同一亚属内人工榕树种间杂交F1代一般可育, 不同亚属榕树的种间杂交亲和性强度在不同性系统上表现有所不同。种间存在单向或不对称的双向基因流, 依赖专性传粉榕小蜂传粉可能使得渐渗杂交成为榕树种间杂交的主要方式。一系列的合子前隔离机制, 包括化学隔离、形态隔离、地理隔离、生态隔离、季节隔离等有效维持了榕树物种在遗传和形态上的完整性; 而合子后隔离作用较弱, 传粉榕小蜂在非专性宿主上的繁殖适合度一般表现为显著降低。未来有待在评估杂交对榕树生物多样性和榕-传粉榕小蜂共生体系稳定性的影响, 分析榕树天然杂交带的杂交模式, 以及探讨影响宿主转移和榕树杂交的因素等方面开展深入研究。

关键词: 榕树, 种间杂交, 宿主转移, 隔离, 传粉榕小蜂

Abstract:

Hybridization plays a vitally important role in biological evolution and speciation. Although occurring frequently in nature, the prevalence of hybridization events is unevenly distributed across the plants. It is generally considered unlikely for the obligate insect-pollinated plants, due to the much stronger prezygotic barriers which were developed during their long co-evolutionary with the host-specific pollinators, such as the fig-fig-pollinating wasp mutualism. Species-specificity in fig pollination appears to be extreme compared with most other insect pollination mutualisms. Most fig species are pollinated by only one wasp species and most wasps are associated with just a single fig species. However, increasing cases of host shift have been reported with the deepening of research, which raises the research and discussion on hybridization between host fig species. Here, the research progress on the interspecific hybridization in Ficus is presented from the following five aspects, artificial hybridization, hybridization between exotic and native species, natural hybridization of island species, natural hybridization of sympatric allied species, and hypothesized hybridization by phylogenetic incongruence. Some further research prospects on the Ficus interbreeding are also outlined. Artificial F1 hybrids between the closely related species of the same subgenus are usually fertile. However, intensity difference of cross-fertilize compatibility between species of different subgenera exists between the different breeding systems. There is unidirectional or bidirectional but asymmetrical interspecific gene flow. Introgression may be the most prominently and prevalently hybridization process in Ficus because of the extreme dependence on pollinating fig wasps for sexual reproduction. A series of prezygotic isolation mechanisms maintain the genetic and morphological identity of fig species, including chemical, mechanical, geographic, temporal and ecological isolation. However, the postzygotic isolation is weak effective. The reproductive fitness of pollinating fig wasp is reduced obviously in atypical host species. Future research work needs to be carried out in investigating the effect of hybridization on fig biodiversity and the stability of the fig-fig-pollinating wasp mutualism, and exploring hybridization pattern and consequence of the hybrid zone, and the factors that affect the host shift and hybridization, and so on.

Key words: Ficus, interspecific hybridization, host shift, isolation, pollinating fig wasp