Universidad Autónoma de Yucatán, Departamento de Ecología Tropical, Km. 15·5 carretera Mérida - Xmatkuil, Mérida, Yucatán, 97000, México.
Ann Bot. 2012 Aug;110(3):535-53. doi: 10.1093/aob/mcs124. Epub 2012 Jun 8.
New data are presented on the distribution and frequency of self-sterility (SS) - predominantly pre-zygotic self-incompatibility (SI) systems - in flowering plants and the hypothesis is tested that families with self-sterile taxa have higher net diversification rates (DRs) than those with exclusively self-compatible taxa using both absolute and relative rate tests.
Three major forms of SI systems (where pollen is rejected at the stigmatic, stylar or ovarian interface) are found to occur in the oldest families of flowering plants, with times of divergence >100 million years before the present (mybp), while post-fertilization SS and heterostyly appear in families with crown ages of 81 and 87 mybp, respectively. It is also founnd that many (22) angiosperm families exhibit >1 SI phenotype and that the distribution of different types of SS does not show strong phylogenetic clustering, collectively suggesting that SS and SI systems have evolved repeatedly de novo in angiosperm history. Families bearing self-sterile taxa have higher absolute DRs using all available calibrations of the angiosperm tree, and this affect is caused mostly by the high DR of families with homomorphic SI systems (in particular stigmatic SI) or those in which multiple SS/SI phenotypes have been observed (polymorphic). Lastly, using sister comparisons, it is further demonstrated that in 29 of 38 sister pairs (including 95 families), the self-sterile sister group had higher species richness and DR than its self-compatible sister based on either the total number of taxa in the clade with SS or only the estimated fraction to harbour SS based on literature surveys.
Collectively, these analyses point to the importance of SS, particularly pre-zygotic SI in the evolution of flowering plants.
本文呈现了关于有性生殖不育（SS）——主要是前合子自不亲和（SI）系统——在开花植物中的分布和频率的新数据，并通过绝对和相对速率检验测试了具有自不育分类群的科比具有完全自交亲和分类群的科具有更高的净多样化率（DR）的假设。
在最古老的开花植物科中发现了三种主要形式的 SI 系统（花粉在柱头、花柱或卵巢界面被排斥），其分化时间早于现在 1 亿多年（mybp），而受精后的 SS 和异型花柱出现在具有 81 和 87 mybp 冠层年龄的科中。还发现许多（22）个被子植物科表现出>1 种 SI 表型，并且不同类型的 SS 分布没有表现出强烈的系统发育聚类，这共同表明 SS 和 SI 系统在被子植物历史上已经多次从头进化。使用所有可用的被子植物树校准，具有自不育分类群的科具有更高的绝对 DR，而这种影响主要是由具有同形 SI 系统（特别是柱头 SI）或观察到多个 SS/SI 表型的科的高 DR 引起的（多态性）。最后，通过姐妹比较，进一步证明在 38 对姐妹对中的 29 对（包括 95 个科）中，基于 SS 分类群的物种丰富度和 DR，自不育姐妹组高于其自交亲和的姐妹组，这是基于分支中的总分类群数量或仅基于文献调查估计的具有 SS 的分类群的估计分数。
总的来说，这些分析表明 SS，特别是前合子 SI 在开花植物的进化中具有重要性。
