Seed after-ripening is a discrete developmental pathway associated with specific gene networks in Arabidopsis
Seed after-ripening is a discrete developmental pathway associated with specific gene networks in Arabidopsis
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DOI：
10.1111/j.1365-313x.2007.03331.x
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发表时间：
2008-01-01
期刊：
影响因子：
7.2
通讯作者：
Holdsworth, Michael J.
中科院分区：
文献类型：
--
作者：
Carrera, Esther;Holman, Tara;Holdsworth, Michael J.
后熟是干燥种子中发生的一种受时间和环境调控的过程，决定着种子的发芽势。植物激素脱落酸(ABA)的代谢和感知在休眠的启动和维持中都是重要的。然而，通过AR调节休眠或萌发能力的分子机制尚不清楚。为了了解ABA和AR之间的关系，我们分析了种子ABA合成缺陷(aba1-1)或感知缺陷(abi1-1)的拟南芥突变体的基因组表达。尽管吸胀突变种子没有表现出休眠状态，但它们表现出由干燥AR引起的全球基因表达的变化，这与野生型(WT)种子的变化相当。确定了受干种子贮藏正向或负向调控的核心基因集。每一组都包含一个编码抑制或激活ABA功能的基因(分别为LPP2和ABA1)，从而表明了干AR可能通过其调节WT种子随后的发芽势的机制。外源ABA处理后熟的WT种子，并不影响吸胀种子的基因表达模式。结果表明，次级休眠状态恢复了AR状态特异的基因表达模式。提出了一个将ABA在种子休眠中的作用与AR和干藏调控基因表达分离的模型。这些结果对研究作物驯化到农业中引起的种子遗传机制变化以及自然生态系统中种子在休眠循环中的行为具有重要意义。
After-ripening (AR) is a time and environment regulated process occurring in the dry seed, which determines the germination potential of seeds. Both metabolism and perception of the phytohormone abscisic acid (ABA) are important in the initiation and maintenance of dormancy. However, molecular mechanisms that regulate the capacity for dormancy or germination through AR are unknown. To understand the relationship between ABA and AR, we analysed genome expression in Arabidopsis thaliana mutants defective in seed ABA synthesis (aba1-1) or perception (abi1-1). Even though imbibed mutant seeds showed no dormancy, they exhibited changes in global gene expression resulting from dry AR that were comparable with changes occurring in wild-type (WT) seeds. Core gene sets were identified that were positively or negatively regulated by dry seed storage. Each set included a gene encoding repression or activation of ABA function (LPP2 and ABA1, respectively), thereby suggesting a mechanism through which dry AR may modulate subsequent germination potential in WT seeds. Application of exogenous ABA to after-ripened WT seeds did not reimpose characteristics of freshly harvested seeds on imbibed seed gene expression patterns. It was shown that secondary dormancy states reinstate AR status-specific gene expression patterns. A model is presented that separates the action of ABA in seed dormancy from AR and dry storage regulated gene expression. These results have major implications for the study of genetic mechanisms altered in seeds as a result of crop domestication into agriculture, and for seed behaviour during dormancy cycling in natural ecosystems.