Developmental selection within the angiosperm style: using gamete DNA to visualize interspecific pollen competition.
Developmental selection within the angiosperm style: using gamete DNA to visualize interspecific pollen competition.
复制标题
被子植物风格内的发育选择：使用配子 DNA 可视化种间花粉竞争。
DOI：
10.1073/pnas.96.16.9201
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发表时间：
1999
影响因子：
11.1
通讯作者：
M. Arnold
中科院分区：
文献类型：
--
作者：
J. H. Williams;W. Friedman;M. Arnold
在有花植物中，雌性通常对柱头上花粉的遗传相关性几乎没有控制力。因此，授粉后过程是最重要的配偶歧视。在柱头、花柱和子房的雌性组织中，花粉管生长期间在雄配子中筛选和选择的能力对于配偶选择和生殖隔离的过程至关重要。然而，直接证据的机械/发育过程与开花植物的择偶是稀疏的。我们研究了两个风媒传粉的桦树（桦木），通常在自然界中杂交后授粉，prefertilization过程中生殖隔离的贡献。我们利用这两个物种之间的倍性水平的3倍差异，以确定在雌性生殖组织内生长的单个花粉管的亲子关系。然后，我们跟踪其发展的命运，同种，异种和混合物种杂交。这种设计允许直接比较负责生殖隔离在单一物种和混合物种授粉的发育过程。我们的研究结果具有重要的意义，在自然群体中的杂交动态的群体遗传结果。杂交后代的亲子关系分析表明，同种花粉管的后代超过98%的幼苗。有偏见的父系成功不是差异胚胎流产的结果。我们检测到强大的，早期的授粉后障碍，如花粉管不亲和，缓慢的花粉管生长，生殖细胞有丝分裂延迟。同种受精优先是由有利或不利的雄性-雌性相互作用介导的，但没有证据表明存在拮抗性雄性-雄性相互作用。
Among flowering plants, females often have little control over the genetic relatedness of pollen deposited on stigmas. Thus, postpollination processes are of primary importance for mate discrimination. The ability to screen and select among male gametes during pollen tube growth within the female tissues of the stigma, style, and ovary is critical to the process of mate choice and reproductive isolation. However, direct evidence of the mechanistic/developmental processes associated with mate choice in flowering plants is sparse. We studied the contribution of postpollination, prefertilization processes to reproductive isolation in two wind-pollinated species of birch (Betula) that commonly hybridize in nature. We exploited the 3-fold difference in ploidy level between these two species to determine the paternity of individual pollen tubes growing within female reproductive tissues. We then tracked their developmental fate in conspecific, heterospecific, and mixed-species crosses. This design allowed a direct comparison of developmental processes responsible for reproductive isolation in both single-species and mixed-species pollinations. Our results have important implications for the population genetic outcome of hybridization dynamics in natural populations. Paternity analysis of progeny from mixed-species pollinations revealed that conspecific pollen tubes sired more than 98% of seedlings. Biased siring success was not the result of differential embryo abortion. We detected strong, early postpollination barriers such as pollen tube incompatibility, slower pollen tube growth, and delayed generative cell mitosis. Conspecific fertilization precedence was mediated by favorable or unfavorable male-female interactions, but there was no evidence for antagonistic male-male interactions.