Diversification of phytochrome contributions to germination as a function of seed-maturation environment
Diversification of phytochrome contributions to germination as a function of seed-maturation environment
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DOI：
10.1111/j.1469-8137.2007.02281.x
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发表时间：
2008-01-01
期刊：
影响因子：
9.4
通讯作者：
Chiang, George C. K.
中科院分区：
文献类型：
--
作者：
Donohue, Kathleen;Heschel, M. Shane;Chiang, George C. K.
种子成熟过程中的环境条件影响萌发，但母体环境对萌发影响的遗传基础实际上是未知的。利用光敏色素的单个和多个突变体，这里表明，不同的光敏色素对萌发的贡献不同，这取决于种子成熟条件。与在温暖温度下成熟的种子相比，在凉爽温度下成熟的类型种子具有强烈的休眠，而这种休眠只有在温暖层积和随后的冷层积后才能被打破。温-冷层积打破了新鲜种子的休眠，但不能打破干燥后熟种子的休眠。功能PHYB和PHYD是必要的，打破冷诱导的休眠，这表明一个以前未知的和生态上重要的功能PHYD。破坏PHYA与PHYD（但不是PHYB）的组合恢复发芽到接近野生型的水平，表明PHYA有助于维持冷诱导的休眠phyD背景。种子成熟温度的影响远大于光周期的影响。PHYB有助于发芽有点更强烈的在短日照下成熟的种子，而PHYD有助于发芽有点更强烈的在长日照下成熟的种子。不同的光敏色素作为种子成熟条件的函数发芽的变量的贡献揭示进一步功能多样化的光敏色素在萌发过程中。这项研究确定了第一个与母体环境对发芽的影响有关的基因。
Environmental conditions during seed maturation influence germination, but the genetic basis of maternal environmental effects on germination is virtually unknown.Using single and multiple mutants of phytochromes, it is shown here that different phytochromes contributed to germination differently, depending on seed-maturation conditions.Arabidopsis thaliana wild-type seeds that were matured under cool temperatures were intensely dormant compared with seeds matured at warmer temperature, and this dormancy was broken only after warm seed-stratification followed by cold seed-stratification. The warm-cold stratification broke dormancy in fresh seeds but not in dry after-ripened seeds. Functional PHYB and PHYD were necessary to break cool-induced dormancy, which indicates a previously unknown and ecologically important function for PHYD. Disruption of PHYA in combination with PHYD (but not PHYB) restored germination to near wild-type levels, indicating that PHYA contributes to the maintenance of cool-induced dormancy on a phyD background. Effects of seed-maturation temperature were much stronger than effects of seed-maturation photoperiod. PHYB contributed to germination somewhat more strongly in seeds matured under short days, whereas PHYD contributed to germination somewhat more strongly in seeds matured under long days.The variable contributions of different phytochromes to germination as a function of seed-maturation conditions reveal further functional diversification of the phytochromes during the process of germination. This study identifies among the first genes to be associated with maternal environmental effects on germination.