欧亚国际

阿拉伯芸苔二态蒸散孢子模型：对亲本和萌发温度响应的不同分子和形态控制

摘要

在条件不可预测的生境中，植物通常具有多样化的对冲策略的特征，以确保适应更广泛的可变环境因素。一个突出的例子是散生孢子（种子和果实）异态性，这种异态性进化是为了最大限度地提高阿拉伯芸苔科（Aethionema arabicum）的物种存活率，其中外部和内源性触发因素允许在同一株植物上产生两个不同的散生孢子。利用这种二态的散孢子模型，我们确定了粘液种子（M+种子形态）、分散的不开裂果实（IND果实形态）和通过从IND果实中去除果皮（果皮）获得的裸露的非粘液M-种子对不同温度的萌发响应的分子、生物物理和生态生理机制。对M+种子、IND果实和M-种子进行大规模的比较转录组和激素分析，为它们独特的热响应提供了全面的数据集。种子中共表达基因模块以及种子和果皮激素含量的形态特异性差异表明，IND 果皮通过产生影响 ABA 敏感性的缺氧来影响被毛休眠。这涉及形态特异性转录因子、缺氧反应和细胞壁重塑基因的表达，以及脱落酸 （ABA） 代谢、转运和信号传导的改变。亲体体温影响ABA含量和ABA相关基因表达，改变IND果皮生物力学特性。阐明水散孢子异态性的分子框架可以深入了解对全球温度变化的发育反应。

The dimorphic diaspore model Aethionema arabicum (Brassicaceae): Distinct molecular and morphological control of responses to parental and germination temperatures

Abstract

Plants in habitats with unpredictable conditions are often characterized by diversifying their bet-hedging strategies that ensure fitness over a wider range of variable environmental factors. A striking example is the diaspore (seed and fruit) heteromorphism that evolved to maximize species survival in Aethionema arabicum (Brassicaceae) in which external and endogenous triggers allow the production of two distinct diaspores on the same plant. Using this dimorphic diaspore model, we identified contrasting molecular, biophysical, and ecophysiological mechanisms in the germination responses to different temperatures of the mucilaginous seeds (M+ seed morphs), the dispersed indehiscent fruits (IND fruit morphs), and the bare non-mucilaginous M- seeds obtained by pericarp (fruit coat) removal from IND fruits. Large-scale comparative transcriptome and hormone analyses of M+ seeds, IND fruits, and M- seeds provided comprehensive datasets for their distinct thermal responses. Morph-specific differences in co-expressed gene modules in seeds, as well as seed and pericarp hormone contents identified a role of the IND pericarp in imposing coat dormancy by generating hypoxia affecting ABA sensitivity. This involved expression of morph-specific transcription factors, hypoxia response and cell wall-remodeling genes, as well as altered abscisic acid (ABA) metabolism, transport, and signaling. Parental temperature affected ABA contents and ABA-related gene expression and altered IND pericarp biomechanical properties. Elucidating the molecular framework underlying the diaspore heteromorphism can provide insight into developmental responses to globally changing temperatures.