Park SeoJung, Moon Jun-Cheol, Park Yong Chan, Kim Ju-Hee, Kim Dong Sub, Jang Cheol Seong
Plant Genomics Lab., Department of Applied Plant Sciences, Kangwon National University, Chuncheon 200-713, Republic of Korea.
Plant Genomics Lab., Department of Applied Plant Sciences, Kangwon National University, Chuncheon 200-713, Republic of Korea; Agriculture and Life Sciences Research Institute, Kangwon National University, Chuncheon 200-713, Republic of Korea.
J Plant Physiol. 2014 Nov 1;171(17):1645-53. doi: 10.1016/j.jplph.2014.08.002. Epub 2014 Aug 13.
Leucine-rich repeat (LRR) receptor-like kinase (RLK) proteins play key roles in a variety of biological pathways. In a previous study, we analyzed the members of the rice LRR-RLK gene family using in silico analysis. A total of 23 LRR-RLK genes were selected based on the expression patterns of a genome-wide dataset of microarrays. The Oryza sativa gamma-ray induced LRR-RLK1 (OsGIRL1) gene was highly induced by gamma irradiation. Therefore, we studied its expression pattern in response to various different abiotic and phytohormone treatments. OsGIRL1 was induced on exposure to abiotic stresses such as salt, osmotic, and heat, salicylic acid (SA), and abscisic acid (ABA), but exhibited downregulation in response to jasmonic acid (JA) treatment. The OsGIRL1 protein was clearly localized at the plasma membrane. The truncated proteins harboring juxtamembrane and kinase domains (or only harboring a kinase domain) exhibited strong autophosphorylation. The biological function of OsGIRL1 was investigated via heterologous overexpression of this gene in Arabidopsis plants subjected to gamma-ray irradiation, salt stress, osmotic stress, and heat stress. A hypersensitive response was observed in response to salt stress and heat stress, whereas a hyposensitive response was observed in response to gamma-ray treatment and osmotic stress. These results provide critical insights into the molecular functions of the rice LRR-RLK genes as receptors of external signals.
富含亮氨酸重复序列（LRR）的类受体激酶（RLK）蛋白在多种生物途径中发挥关键作用。在之前的一项研究中，我们通过电子分析对水稻LRR-RLK基因家族的成员进行了分析。基于全基因组微阵列数据集的表达模式，共选择了23个LRR-RLK基因。水稻γ射线诱导的LRR-RLK1（OsGIRL1）基因在γ射线照射下被高度诱导。因此，我们研究了其在响应各种不同非生物和植物激素处理时的表达模式。OsGIRL1在暴露于盐、渗透和热等非生物胁迫、水杨酸（SA）和脱落酸（ABA）时被诱导，但在茉莉酸（JA）处理下表现出下调。OsGIRL1蛋白明显定位于质膜。含有近膜和激酶结构域（或仅含有激酶结构域）的截短蛋白表现出强烈的自磷酸化。通过在遭受γ射线照射、盐胁迫、渗透胁迫和热胁迫的拟南芥植物中异源过表达该基因，研究了OsGIRL1的生物学功能。在响应盐胁迫和热胁迫时观察到超敏反应，而在响应γ射线处理和渗透胁迫时观察到低敏反应。这些结果为水稻LRR-RLK基因作为外部信号受体的分子功能提供了关键见解。
