Baek Woonhee, Lim Sohee, Lee Sung Chul
Department of Life Science (BK21 Program), Chung-Ang University, Seoul, 156-756, Republic of Korea.
Plant Mol Biol. 2016 May;91(1-2):149-60. doi: 10.1007/s11103-016-0451-1. Epub 2016 Feb 11.
Plants are constantly challenged by various environmental stresses, including high salinity and drought, and they have evolved defense mechanisms to counteract the deleterious effects of these stresses. The plant hormone abscisic acid (ABA) regulates plant growth and developmental processes and mediates abiotic stress responses. Here, we identified the Capsicum annuum DRought Tolerance 1 (CaDRT1) gene from pepper leaves treated with ABA. CaDRT1 was strongly expressed in pepper leaves in response to environmental stresses and after ABA treatment, suggesting that the CaDRT1 protein functions in the abiotic stress response. Knockdown expression of CaDRT1 via virus-induced gene silencing resulted in a high level of drought susceptibility, and this was characterized by increased transpirational water loss via decreased stomatal closure. CaDRT1-overexpressing (OX) Arabidopsis plants exhibited an ABA-hypersensitive phenotype during the germinative, seedling, and adult stages. Additionally, these CaDRT1-OX plants exhibited a drought-tolerant phenotype characterized by low levels of transpirational water loss, high leaf temperatures, increased stomatal closure, and enhanced expression levels of drought-responsive genes. Taken together, our results suggest that CaDRT1 is a positive regulator of the ABA-mediated drought stress response.
植物不断受到各种环境胁迫的挑战，包括高盐度和干旱，并且它们已经进化出防御机制来抵消这些胁迫的有害影响。植物激素脱落酸（ABA）调节植物生长和发育过程，并介导非生物胁迫响应。在此，我们从经ABA处理的辣椒叶片中鉴定出辣椒耐旱1（CaDRT1）基因。CaDRT1在辣椒叶片中对环境胁迫以及ABA处理后强烈表达，这表明CaDRT1蛋白在非生物胁迫响应中发挥作用。通过病毒诱导的基因沉默对CaDRT1进行敲低表达导致高度干旱敏感性，其特征是通过气孔关闭减少导致蒸腾失水增加。过表达CaDRT1（OX）的拟南芥植物在萌发、幼苗和成株阶段表现出ABA超敏感表型。此外，这些CaDRT1 - OX植物表现出耐旱表型，其特征是蒸腾失水量低、叶片温度高、气孔关闭增加以及干旱响应基因的表达水平增强。综上所述，我们的结果表明CaDRT1是ABA介导的干旱胁迫响应的正调节因子。
