Chibani Kamel, Ali-Rachedi Sonia, Job Claudette, Job Dominique, Jullien Marc, Grappin Philippe
Institut National de la Recherche Agronomique-Institut National Agronomique Paris-Grignon, Chaire de Physiologie Végétale, Unité Mixte de Recherche 204, F-75231 Paris cedex 05, France.
Plant Physiol. 2006 Dec;142(4):1493-510. doi: 10.1104/pp.106.087452. Epub 2006 Oct 6.
The mechanisms controlling seed dormancy in Arabidopsis (Arabidopsis thaliana) have been characterized by proteomics using the dormant (D) accession Cvi originating from the Cape Verde Islands. Comparative studies carried out with freshly harvested dormant and after-ripened non-dormant (ND) seeds revealed a specific differential accumulation of 32 proteins. The data suggested that proteins associated with metabolic functions potentially involved in germination can accumulate during after-ripening in the dry state leading to dormancy release. Exogenous application of abscisic acid (ABA) to ND seeds strongly impeded their germination, which physiologically mimicked the behavior of D imbibed seeds. This application resulted in an alteration of the accumulation pattern of 71 proteins. There was a strong down-accumulation of a major part (90%) of these proteins, which were involved mainly in energetic and protein metabolisms. This feature suggested that exogenous ABA triggers proteolytic mechanisms in imbibed seeds. An analysis of de novo protein synthesis by two-dimensional gel electrophoresis in the presence of [(35)S]-methionine disclosed that exogenous ABA does not impede protein biosynthesis during imbibition. Furthermore, imbibed D seeds proved competent for de novo protein synthesis, demonstrating that impediment of protein translation was not the cause of the observed block of seed germination. However, the two-dimensional protein profiles were markedly different from those obtained with the ND seeds imbibed in ABA. Altogether, the data showed that the mechanisms blocking germination of the ND seeds by ABA application are different from those preventing germination of the D seeds imbibed in basal medium.
利用源自佛得角群岛的休眠（D）生态型Cvi，通过蛋白质组学对拟南芥（Arabidopsis thaliana）种子休眠的控制机制进行了表征。对新鲜收获的休眠种子和后熟非休眠（ND）种子进行的比较研究揭示了32种蛋白质的特异性差异积累。数据表明，与可能参与萌发的代谢功能相关的蛋白质在干燥状态下的后熟过程中会积累，从而导致休眠解除。对ND种子外源施加脱落酸（ABA）强烈阻碍其萌发，这在生理上模拟了吸胀D种子的行为。这种处理导致71种蛋白质的积累模式发生改变。这些蛋白质中的大部分（90%）强烈下调积累，它们主要参与能量代谢和蛋白质代谢。这一特征表明外源ABA触发了吸胀种子中的蛋白水解机制。在存在[(35)S]-甲硫氨酸的情况下，通过二维凝胶电泳对从头蛋白质合成进行分析，结果表明外源ABA在吸胀过程中并不阻碍蛋白质生物合成。此外，吸胀的D种子被证明能够进行从头蛋白质合成，这表明蛋白质翻译受阻不是观察到的种子萌发受阻的原因。然而，二维蛋白质图谱与在ABA中吸胀的ND种子所获得的图谱明显不同。总之，数据表明，通过施加ABA来阻止ND种子萌发的机制与阻止在基础培养基中吸胀的D种子萌发的机制不同。
