Disruption of endosperm development is a major cause of hybrid seed inviability between Mimulus guttatus and Mimulus nudatus.
Disruption of endosperm development is a major cause of hybrid seed inviability between Mimulus guttatus and Mimulus nudatus.
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DOI：
10.1111/nph.13842
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发表时间：
2016-05
期刊：
影响因子：
--
通讯作者：
Franks RG
中科院分区：
文献类型：
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作者：
Oneal E;Willis JH;Franks RG
种群内发育机制的差异可能导致杂种发育失败，并且可能是驱动被子植物物种形成的因素。我们研究了 Mimulus guttatus 和密切相关的蛇纹石特有 M. nudatus 的胚乳和胚胎发育模式，并将它们与相互杂交种子的胚乳和胚胎发育模式进行了比较。我们探讨杂交种子发育的破坏是否是这些同域类群之间生殖隔离的主要根源。 M. guttatus 和 M. nudatus 的不同之处在于胚乳和胚胎发育的模式和时间。一些杂交种子表现出胚乳发育的早期破坏并且完全无法存活，而另一些杂交种子起初发育相对正常，但后来表现出胚乳增殖受损和发芽成功率低。这些发育模式反映在成熟的杂交种子中，这些种子要么小而扁平（表明胚乳很少甚至没有），要么干瘪（表明胚乳体积减少）。杂交种子的不活力在 M. guttatus 和 M. nudatus 之间形成了有效的繁殖屏障。我们揭示了M. guttatus物种复合体（一个重要的生态模型系统）中密切相关物种之间发育变异的程度，并为M. guttatus和M. nudatus之间的混合屏障提供了部分机制。
Divergence of developmental mechanisms within populations may lead to hybrid developmental failure, and may be a factor driving speciation in angiosperms. We investigate patterns of endosperm and embryo development in Mimulus guttatus and the closely related, serpentine endemic M. nudatus, and compare them to those of reciprocal hybrid seed. We address whether disruption in hybrid seed development is the primary source of reproductive isolation between these sympatric taxa. M. guttatus and M. nudatus differ in the pattern and timing of endosperm and embryo development. Some hybrid seed exhibit early disruption of endosperm development and are completely inviable, while others develop relatively normally at first, but later exhibit impaired endosperm proliferation and low germination success. These developmental patterns are reflected in mature hybrid seed, which are either small and flat (indicating little to no endosperm), or shriveled (indicating reduced endosperm volume). Hybrid seed inviability forms a potent reproductive barrier between M. guttatus and M. nudatus. We shed light on the extent of developmental variation between closely related species within the M. guttatus species complex, an important ecological model system, and provide a partial mechanism for the hybrid barrier between M. guttatus and M. nudatus.