School of Plant Sciences and Food Security, Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
School of Plant Sciences and Food Security, Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel.
Plant Physiol. 2019 Jun;180(2):1101-1118. doi: 10.1104/pp.19.00119. Epub 2019 Mar 20.
Salinity impairs seed germination and seedling establishment. We investigated the role of Arabidopsis () CALMODULIN-BINDING TRANSCRIPTION ACTIVATOR 6 (CAMTA6) in salinity stress responses during early germination. Compared with the wild type, the and mutants were more tolerant to NaCl and abscisic acid (ABA) and accumulated less Na In contrast, 4- to 11-d-old seedlings were more sensitive to NaCl. In , expression of (), encoding an Na/K transporter, was restricted to the radicles and was not enhanced by NaCl or ABA. During germination, the double mutant was as sensitive as the wild type and to NaCl, suggesting that HKT1;1 is crucial for the salt tolerance of An ABA response element in the promoter was found to be indispensable for the enhanced expression of the gene in response to NaCl and to ABA. Transcriptome analysis of the wild type and with and without salt treatment revealed 1,020 up-regulated and 1,467 down-regulated salt-responsive genes in the wild type. Among these, 638 up-regulated and 1,242 down-regulated genes were classified as CAMTA6-dependent. Expression of several known salt stress-associated genes, including and , was impaired in mutants. Bioinformatics analysis of the 5' upstream sequences of the salt-responsive CAMTA6-dependent up-regulated genes revealed the CACGTGTC motif as the most prominent element, representing an ABA response element and a potential CAMTA-binding site. We suggest that CAMTA6 regulates, directly or indirectly, the expression of most of the salt-responsive genes in germinating seeds, including genes that are crucial for Na homeostasis and salt stress tolerance.
盐度会损害种子的萌发和幼苗的建立。我们研究了拟南芥（Arabidopsis）钙调素结合转录激活因子 6（CAMTA6）在早期萌发过程中盐胁迫反应中的作用。与野生型相比，和突变体对 NaCl 和脱落酸（ABA）更耐受，积累的 Na 较少；相反，4-11 天大的幼苗对 NaCl 更敏感。在，编码 Na/K 转运蛋白的基因的表达仅限于胚根，不受 NaCl 或 ABA 的增强。在萌发过程中，双突变体与野生型和一样对 NaCl 敏感，表明 HKT1;1 对于的耐盐性至关重要。在启动子中发现一个 ABA 反应元件对于基因在响应 NaCl 和 ABA 时的增强表达是必不可少的。对野生型和用盐处理和未用盐处理的转录组分析显示，野生型中有 1020 个上调和 1467 个下调的盐响应基因。其中，638 个上调和 1242 个下调基因被归类为依赖 CAMTA6。几个已知的与盐胁迫相关的基因，包括和，在突变体中的表达受损。对盐响应依赖 CAMTA6 的上调基因的 5'上游序列进行生物信息学分析，揭示了 CACGTGTC 基序作为最突出的元件，代表了 ABA 反应元件和潜在的 CAMTA 结合位点。我们认为，CAMTA6 直接或间接调节萌发种子中大多数盐响应基因的表达，包括对 Na 稳态和耐盐性至关重要的基因。
