Role of a LRR-RLK in Regulating Ethylene Biosynthesis and Anisotropic Cell Elongation in Roots

细胞如何调节它们的扩张是现代生物学的中心问题。在植物中，不对称的细胞扩张是器官大小和形状的主要决定因素。然而，很少有人知道有关的分子机制，在植物细胞扩增的调节。一对来自拟南芥的受体样激酶，称为AIK 1和AIK 2，已被鉴定为直接与ACC合酶相互作用，ACC合酶催化植物激素乙烯生物合成中的限速步骤。遗传学研究表明，这些AIK基因在调节根细胞的细胞扩增中起重要作用。乙烯促进植物细胞的径向膨胀，并且发现aik 1/aik 2双突变体中的径向膨胀表型依赖于乙烯。这一点，再加上观察到这些蛋白质直接与ACC合酶相互作用，表明这些AIK基因参与乙烯和定向细胞扩增之间的相互作用。这种相互作用将进一步探讨精确描绘的AIK突变对根的生长特性的影响，并通过确定这些基因是否直接调节功能的细胞参与指导细胞伸长，如细胞壁。乙烯在aik突变体表型中的作用将通过遗传学和生物化学的方法进行探讨。最后，这些AIK激酶的其他目标将寻求在酵母中使用一个简单的相互作用屏幕。这项研究将揭示植物如何调节细胞伸长，这对理解植物形态的发展至关重要。该提案还将为本科生和研究生提供跨学科培训机会，包括细胞生物学，植物生理学，分子遗传学和生物化学。

How cell regulate their expansion is central question in modern biology. In plants, asymmetric cell expansion is a primary determinant of the size and shape of organs. However, very little is known regarding the molecular mechanisms underlying the regulation of cell expansion in plants. A pair of receptor-like kinases from Arabidopsis, called AIK1 and AIK2, has been identified that directly interact with ACC synthase, the enzyme that catalyzes the rate-limiting step in the biosynthesis of the plant hormone ethylene. Genetic studies have revealed that these AIK genes play an important role in regulating cell expansion in root cells. Ethylene promotes radial expansion of plant cells, and the radial swelling phenotype in the aik1/aik2 double mutant was found to be dependent on ethylene. This, coupled with the observation that these proteins directly interact with ACC synthase, suggests that these AIK genes are involved in the interaction between ethylene and directed cell expansion. This interaction will be further explored by precisely delineating the effects of the AIK mutations on the growth characteristics of the root and by determining if these genes directly regulate features of the cell involved in directing cell elongation, such as the cell wall. The role of ethylene in the aik mutant phenotype will be explored using genetic and biochemical approaches. Finally, additional targets of these AIK kinases will be sought using a simple interaction screen in yeast. This research will shed light on how plants regulate cell elongation, which is crucial to understanding the development of plant form.The proposal will also provide interdisciplinary training opportunities for undergraduate and graduate students in diverse areas including cell biology, plant physiology, molecular genetics, and biochemistry.