The etr1-2 mutation in Arabidopsis thaliana affects the abscisic acid, auxin, cytokinin and gibberellin metabolic pathways during maintenance of seed dormancy, moist-chilling and germination
The etr1-2 mutation in Arabidopsis thaliana affects the abscisic acid, auxin, cytokinin and gibberellin metabolic pathways during maintenance of seed dormancy, moist-chilling and germination
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DOI：
10.1111/j.1365-313x.2005.02359.x
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发表时间：
2005-04-01
期刊：
影响因子：
7.2
通讯作者：
Kermode, AR
中科院分区：
文献类型：
--
作者：
Chiwocha, SDS;Cutler, AJ;Kermode, AR
在拟南芥中，etr 1 -2突变赋予显性乙烯不敏感性，并导致与野生型成熟种子相比，表现出休眠的成熟种子的比例更大。我们通过HPLC-ESI/MS/MS分析野生型和etr 1 -2植物成熟种子中四类植物激素及其代谢产物的谱，研究了etr 1 -2突变对其他植物激素的影响。激素代谢产物进行了分析，在种子吸胀发芽条件下立即，在种子进行了7天的低温（层积）期，在发芽/早期发芽后的生长。高于野生型水平的脱落酸（阿坝）似乎有助于，至少在一定程度上，在etr 1 -2的成熟种子休眠的发病率更高。与野生型种子相比，在萌发条件下（有和没有低温处理），脱落酸葡萄糖酯（ABA-GE）在etr 1 -2种子的较低水平表明，阿坝代谢减少ABA-GE可能有助于阿坝的积累在萌发过程中的突变体。突变体种子表现出普遍较高的生长素水平和吲哚-3-天冬氨酸的大量积累时，放置在发芽条件下，低温。该突变体通过玉米素-O-葡萄糖基化（Z-O-Glu）表现出细胞分裂素葡萄糖苷水平的增加。由此产生的Z-O-Glu增加是与ETR 1基因突变相关的最大和最一致的变化。有更多的赤霉素（GA）和更高的浓度在突变体比野生型。我们的研究结果表明，乙烯信号调节种子中所有其他植物激素途径的代谢。此外，etr 1 -2种子在萌发过程中的激素分布表明，在没有功能性乙烯信号传导途径的情况下，需要高于野生型水平的GA来促进萌发。
In Arabidopsis thaliana, the etr1-2 mutation confers dominant ethylene insensitivity and results in a greater proportion of mature seeds that exhibit dormancy compared with mature seeds of the wild-type. We investigated the impact of the etr1-2 mutation on other plant hormones by analyzing the profiles of four classes of plant hormones and their metabolites by HPLC-ESI/MS/MS in mature seeds of wild-type and etr1-2 plants. Hormone metabolites were analyzed in seeds imbibed immediately under germination conditions, in seeds subjected to a 7-day moist-chilling (stratification) period, and during germination/early post-germinative growth. Higher than wild-type levels of abscisic acid (ABA) appeared to contribute, at least in part, to the greater incidence of dormancy in mature seeds of etr1-2. The lower levels of abscisic acid glucose ester (ABA-GE) in etr1-2 seeds compared with wild-type seeds under germination conditions (with and without moist-chilling treatments) suggest that reduced metabolism of ABA to ABA-GE likely contributed to the accumulation of ABA during germination in the mutant. The mutant seeds exhibited generally higher auxin levels and a large build-up of indole-3-aspartate when placed in germination conditions following moist-chilling. The mutant manifested increased levels of cytokinin glucosides through zeatin-O-glucosylation (Z-O-Glu). The resulting increase in Z-O-Glu was the largest and most consistent change associated with the ETR1 gene mutation. There were more gibberellins (GA) and at higher concentrations in the mutant than in wild-type. Our results suggest that ethylene signaling modulates the metabolism of all the other plant hormone pathways in seeds. Additionally, the hormone profiles of etr1-2 seed during germination suggest a requirement for higher than wild-type levels of GA to promote germination in the absence of a functional ethylene signaling pathway.