Comparative analysis of corolla tube development across three closely related Mimulus species with different pollination syndromes
Comparative analysis of corolla tube development across three closely related Mimulus species with different pollination syndromes
复制标题
DOI：
10.1111/ede.12368
复制
发表时间：
2021-01-07
影响因子：
2.9
通讯作者：
Diggle, Pamela K.
中科院分区：
文献类型：
--
作者：
Gurung, Vandana;Yuan, Yao-Wu;Diggle, Pamela K.
花瓣融合形成花冠管被认为是促进许多开花植物谱系多样化的关键创新。花冠管长度在不同物种之间往往差异很大，是传粉者喜好的主要决定因素。然而，我们对花冠管长度变化背后的发育动力学的了解非常有限。在这里，我们研究了Limulus lewisii物种复合体中的花冠管生长，这是一个新兴的模式系统，用于研究传粉者相关花性状的发育遗传学和胚胎发育。我们比较了与花冠管长度变化相关的发育过程和细胞过程，这些过程与蜜蜂授粉的勒维希米、蜂鸟授粉的马鞭草和自花授粉的帕里希姆之间的发育和细胞过程有关。我们发现，在所有三种植物中，细胞大小都不均匀地分布在成熟管上，最长的细胞正好位于雄蕊着生部位的远端。三个物种之间花冠管长度的差异与器官发生或早期发育过程无关，但与发育后期发生的多个过程的差异有关，包括细胞分裂和细胞伸长的位置和持续时间。小花的管生长曲线和大花的管生长曲线基本上是难以区分的，除了管在较小的尺寸时停止生长的时间较早，这表明异时性在从异交到自交的转变中起着关键作用。这些结果不仅突出了与花冠管在物种间变异有关的发育过程，而且为在这一新兴模式系统中对花冠管形态发生变化的突变体或转基因植物进行未来的发育遗传学分析提供了基准参考。
Fusion of petals to form a corolla tube is considered a key innovation contributing to the diversification of many flowering plant lineages. Corolla tube length often varies dramatically among species and is a major determinant of pollinator preference. However, our understanding of the developmental dynamics underlying corolla tube length variation is very limited. Here we examined corolla tube growth in the Mimulus lewisii species complex, an emerging model system for studying the developmental genetics and evo-devo of pollinator-associated floral traits. We compared developmental and cellular processes associated with corolla tube length variation among the bee-pollinated M. lewisii, the hummingbird-pollinated Mimulus verbenaceus, and the self-pollinated Mimulus parishii. We found that in all three species, cell size is non-uniformly distributed along the mature tube, with the longest cells just distal to the stamen insertion site. Differences in corolla tube length among the three species are not associated with processes of organogenesis or early development but are associated with variation in multiple processes occurring later in development, including the location and duration of cell division and cell elongation. The tube growth curves of the small-flowered M. parishii and large-flowered M. lewisii are essentially indistinguishable, except that M. parishii tubes stop growing earlier at a smaller size, suggesting a critical role of heterochrony in the shift from outcrossing to selfing. These results not only highlight the developmental process associated with corolla tube variation among species but also provide a baseline reference for future developmental genetic analyses of mutants or transgenic plants with altered corolla tube morphology in this emerging model system.