Plants being sessile integrate information from a variety of endogenous and external cues simultaneously to optimize growth and development. This necessitates the signaling networks in plants to be highly dynamic and flexible. One such network involves heterotrimeric G-proteins comprised of Gα, Gβ, and Gγ subunits, which influence many aspects of growth, development, and stress response pathways. In plants such as Arabidopsis, a relatively simple repertoire of G-proteins comprised of one canonical and three extra-large Gα, one Gβ and three Gγ subunits exists. Because the Gβ and Gγ proteins form obligate dimers, the phenotypes of plants lacking the sole Gβ or all Gγ genes are similar, as expected. However, Gα proteins can exist either as monomers or in a complex with Gβγ, and the details of combinatorial genetic and physiological interactions of different Gα proteins with the sole Gβ remain unexplored. To evaluate such flexible, signal-dependent interactions and their contribution toward eliciting a specific response, we have generated Arabidopsis mutants lacking specific combinations of Gα and Gβ genes, performed extensive phenotypic analysis, and evaluated the results in the context of subunit usage and interaction specificity. Our data show that multiple mechanistic modes, and in some cases complex epistatic relationships, exist depending on the signal-dependent interactions between the Gα and Gβ proteins. This suggests that, despite their limited numbers, the inherent flexibility of plant G-protein networks provides for the adaptability needed to survive under continuously changing environments.

中文翻译：

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G蛋白亚基之间灵活的功能相互作用有助于植物反应的特异性。

无柄植物会同时整合来自各种内源和外部线索的信息，以优化生长和发育。这使得工厂中的信令网络必须高度动态和灵活。一个这样的网络涉及由Gα，Gβ和Gγ亚基组成的异三聚体G蛋白，它们影响生长，发育和应激反应途径的许多方面。在拟南芥（Arabidopsis）等植物中，存在一个相对简单的G蛋白库，该库由一个规范的和三个超大的Gα，一个Gβ和三个Gγ亚基组成。由于Gβ和Gγ蛋白形成专性二聚体，因此缺少唯一Gβ或所有Gγ基因的植物的表型与预期的相似。但是，Gα蛋白既可以单体形式存在，也可以与Gβγ形成复合物，尚未探讨不同Gα蛋白与唯一Gβ的组合遗传和生理相互作用的细节。为了评估这种灵活的，信号依赖性的相互作用及其对引起特定反应的贡献，我们生成了缺乏Gα和Gβ基因特定组合的拟南芥突变体，进行了广泛的表型分析，并在亚基使用和相互作用特异性的背景下评估了结果。我们的数据表明，取决于Gα和Gβ蛋白之间的信号依赖性相互作用，存在多种机制模式，在某些情况下还存在复杂的上位关系。这表明，尽管其数量有限，但植物G蛋白网络的固有灵活性提供了在不断变化的环境中生存所需的适应性。