Department of Plant Biotechnology, Chonnam National University, Gwangju, 61186, Republic of Korea.
Department of Food Science & Technology, Chonnam National University, Gwangju, 61186, Republic of Korea.
Plant Mol Biol. 2019 Mar;99(4-5):363-377. doi: 10.1007/s11103-019-00822-0. Epub 2019 Jan 12.
Destruction of PAP phosphatase AHL suppresses atrzf1 phenotype in abiotic stress responses. AHL plays an intermediate role in the regulation of proline accumulation by PAP nucleotidase. Proline (Pro) metabolism is important for environmental responses, plant development, and growth. However, the role of Pro in abiotic stress process is unclear. Using atrzf1 (Arabidopsis thaliana ring zinc finger 1) mutant as a parental line for T-DNA tagging mutagenesis, we identified a suppressor mutant designated as proline content alterative 17 (pca17) that suppressed insensitivity of atrzf1 to abiotic stresses during early seedling growth. Pro content of pca17 was lower than that in both wild type (WT) and atrzf1 while complementary lines were less sensitive to abscisic acid (ABA) and abiotic stresses compared to WT. Thermal Asymmetric Interlaced (TAIL)-PCR of pca17 showed that T-DNA was inserted at site of At5g54390 (AHL for Arabidopsis Halotolerance 2-like) encoding 3'-phosphoadenosine-5'-phosphate (PAP) phosphatase. Under drought stress condition, products of sulfate metabolism such as PAP and adenosine monophosphate were significantly lower in pca17 than those in WT and atrzf1. Furthermore, pca17 showed significantly higher levels of several important drought parameters including malondialdehyde, ion leakage, and water loss than WT and atrzf1. Fluorescence signal of green fluorescent protein (GFP)-tagged AHL was quite strong in nuclei of the root and guard cells of transgenic seedlings. Additionally, AHL promoter-β-glucuronidase (GUS) construct revealed substantial gene expression in vasculature tissues and pollen. Collectively, these findings demonstrate that pca17 acts as a dominant suppressor mutant of atrzf1 in abiotic stress response by modulating proline and sulfate metabolism.
PAP 磷酸酶 AHL 的破坏抑制了非生物胁迫响应中的 atrzf1 表型。AHL 在 PAP 核苷酸酶调控脯氨酸积累中发挥中间作用。脯氨酸（Pro）代谢对环境响应、植物发育和生长很重要。然而，Pro 在非生物胁迫过程中的作用尚不清楚。我们使用 atrzf1（拟南芥环锌指 1）突变体作为 T-DNA 标记诱变的亲本系，鉴定出一个被命名为脯氨酸含量改变 17 号（pca17）的抑制子突变体，该突变体在幼苗早期生长过程中抑制了 atrzf1 对非生物胁迫的不敏感性。pca17 的 Pro 含量低于野生型（WT）和 atrzf1，而互补系比 WT 对脱落酸（ABA）和非生物胁迫的敏感性较低。pca17 的 TAIL-PCR 显示，T-DNA 插入到编码 3'-磷酸腺苷-5'-磷酸（PAP）磷酸酶的 At5g54390（拟南芥耐盐性 2 样物 AHL）位点。在干旱胁迫条件下，pca17 中的硫酸盐代谢产物如 PAP 和腺苷一磷酸的产物明显低于 WT 和 atrzf1。此外，pca17 表现出比 WT 和 atrzf1 更高的几个重要干旱参数水平，包括丙二醛、离子渗漏和水分损失。转 GFP 标记 AHL 的绿色荧光蛋白（GFP）的荧光信号在根和保卫细胞的细胞核中非常强烈。此外，AHL 启动子-β-葡萄糖醛酸酶（GUS）构建体显示出在脉管组织和花粉中大量的基因表达。总之，这些发现表明，pca17 通过调节脯氨酸和硫酸盐代谢，作为 atrzf1 在非生物胁迫响应中的显性抑制子突变体发挥作用。
