Chai Chenglin, Wang Yongqin, Valliyodan Babu, Nguyen Henry T
Division of Plant Sciences, National Center for Soybean Biotechnology, University of Missouri Columbia, MO, USA.
Front Plant Sci. 2016 Mar 9;7:282. doi: 10.3389/fpls.2016.00282. eCollection 2016.
The phytohormone auxin plays a critical role in regulation of plant growth and development as well as plant responses to abiotic stresses. This is mainly achieved through its uneven distribution in plant via a polar auxin transport process. Auxin transporters are major players in polar auxin transport. The AUXIN RESISTENT 1/LIKE AUX1 (AUX/LAX) auxin influx carriers belong to the amino acid permease family of proton-driven transporters and function in the uptake of indole-3-acetic acid (IAA). In this study, genome-wide comprehensive analysis of the soybean AUX/LAX (GmLAX) gene family, including phylogenic relationships, chromosome localization, and gene structure, was carried out. A total of 15 GmLAX genes, including seven duplicated gene pairs, were identified in the soybean genome. They were distributed on 10 chromosomes. Despite their higher percentage identities at the protein level, GmLAXs exhibited versatile tissue-specific expression patterns, indicating coordinated functioning during plant growth and development. Most GmLAXs were responsive to drought and dehydration stresses and auxin and abscisic acid (ABA) stimuli, in a tissue- and/or time point- sensitive mode. Several GmLAX members were involved in responding to salt stress. Sequence analysis revealed that promoters of GmLAXs contained different combinations of stress-related cis-regulatory elements. These studies suggest that the soybean GmLAXs were under control of a very complex regulatory network, responding to various internal and external signals. This study helps to identity candidate GmLAXs for further analysis of their roles in soybean development and adaption to adverse environments.
植物激素生长素在调节植物生长发育以及植物对非生物胁迫的响应中起着关键作用。这主要是通过生长素在植物体内的极性运输过程实现其不均匀分布来达成的。生长素转运蛋白是极性生长素运输的主要参与者。生长素抗性1/类生长素1（AUX/LAX）生长素内流载体属于质子驱动转运蛋白的氨基酸通透酶家族，在吲哚 - 3 - 乙酸（IAA）的摄取中发挥作用。在本研究中，对大豆AUX/LAX（GmLAX）基因家族进行了全基因组综合分析，包括系统发育关系、染色体定位和基因结构。在大豆基因组中总共鉴定出15个GmLAX基因，包括7对重复基因对。它们分布在10条染色体上。尽管GmLAXs在蛋白质水平上具有较高的同源性，但它们表现出多样的组织特异性表达模式，表明在植物生长发育过程中发挥协同作用。大多数GmLAXs对干旱和脱水胁迫以及生长素和脱落酸（ABA）刺激有响应，且具有组织和/或时间点敏感性。几个GmLAX成员参与了对盐胁迫的响应。序列分析表明，GmLAXs的启动子包含不同组合的胁迫相关顺式调控元件。这些研究表明，大豆GmLAXs受非常复杂的调控网络控制，对各种内部和外部信号作出响应。本研究有助于鉴定候选GmLAXs，以便进一步分析它们在大豆发育和适应逆境中的作用。
