DELAY OF GERMINATION 1 mediates a conserved coat-dormancy mechanism for the temperature- and gibberellin-dependent control of seed germination
DELAY OF GERMINATION 1 mediates a conserved coat-dormancy mechanism for the temperature- and gibberellin-dependent control of seed germination
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DOI：
10.1073/pnas.1403851111
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发表时间：
2014-08-26
影响因子：
11.1
通讯作者：
Leubner-Metzger, Gerhard
中科院分区：
文献类型：
--
作者：
Graeber, Kai;Linkies, Ada;Leubner-Metzger, Gerhard
种子萌发是植物生命周期中的一个重要环节，它决定了植物的生存和繁殖。为了检测发芽的最佳时空条件，种子充当集成环境温度等信息的复杂环境传感器。在这里，我们表明，延迟发芽1（狗1）基因，已知提供休眠适应不同的环境，决定了种子发芽的最佳温度。通过拟南芥科物种之间的相互基因交换实验，我们表明DOG1介导的休眠机制是保守的。生物力学分析表明，这一机制调节胚乳的材料特性，种子组织层作为发芽屏障，以控制外壳休眠。我们发现，DOG1抑制赤霉素（GA）调节的基因编码细胞壁重塑蛋白的表达在温度依赖性的方式。此外，我们表明，DOG1导致种子GA代谢的温度依赖性改变。这些激素代谢的改变是由编码GA生物合成途径的关键酶的基因的温度依赖性差异表达引起的。DOG1的这些作用导致胚乳弱化的温度依赖性控制，并确定萌发的最佳温度。保守的DOG1介导的外套休眠机制提供了一个高度适应性的温度传感机制来控制发芽的时间。
Seed germination is an important life-cycle transition because it determines subsequent plant survival and reproductive success. To detect optimal spatiotemporal conditions for germination, seeds act as sophisticated environmental sensors integrating information such as ambient temperature. Here we show that the DELAY OF GERMINATION 1 (DOG1) gene, known for providing dormancy adaptation to distinct environments, determines the optimal temperature for seed germination. By reciprocal gene-swapping experiments between Brassicaceae species we show that the DOG1-mediated dormancy mechanism is conserved. Biomechanical analyses show that this mechanism regulates the material properties of the endosperm, a seed tissue layer acting as germination barrier to control coat dormancy. We found that DOG1 inhibits the expression of gibberellin (GA)-regulated genes encoding cell-wall remodeling proteins in a temperature-dependent manner. Furthermore we demonstrate that DOG1 causes temperature-dependent alterations in the seed GA metabolism. These alterations in hormone metabolism are brought about by the temperature-dependent differential expression of genes encoding key enzymes of the GA biosynthetic pathway. These effects of DOG1 lead to a temperature-dependent control of endosperm weakening and determine the optimal temperature for germination. The conserved DOG1-mediated coat-dormancy mechanism provides a highly adaptable temperature-sensing mechanism to control the timing of germination.