State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, National Plant Gene Research Centre (Beijing), #2 West Yuan Ming Yuan Rd, Beijing 100193, China.
Mol Plant. 2013 Sep;6(5):1487-502. doi: 10.1093/mp/sst031. Epub 2013 Feb 12.
The Arabidopsis Di19 (Drought-induced) gene family encodes seven Cys2/His2-type zinc-finger proteins, most with unknown functions. Here, we report that Di19 functioned as a transcriptional regulator and was involved in Arabidopsis responses to drought stress through up-regulation of pathogenesis-related PR1, PR2, and PR5 gene expressions. The Di19 T-DNA insertion mutant di19 was much more sensitive to drought stress, whereas the Di19-overexpressing lines were much more tolerant to drought stress compared with wild-type plants. Di19 exhibited transactivation activity in our yeast assay, and its transactivation activity was further confirmed in vivo. DNA-binding analysis revealed that Di19 could bind to the TACA(A/G)T element and chromatin immunoprecipitation (ChIP) assays demonstrated that Di19 could bind to the TACA(A/G)T element within the PR1, PR2, and PR5 promoters. qRT-PCR results showed that Di19 promoted the expressions of PR1, PR2, and PR5, and these heightened expressions were enhanced by CPK11, which interacted with Di19 in the nucleus. Similarly to the Di19-overexpressing line, PR1-, PR2-, and PR5-overexpressing lines also showed the drought-tolerant phenotype. The pre-treatment with salicylic acid analogs INA can enhance plants' drought tolerance. Taken together, these data demonstrate that Di19, a new type of transcription factor, directly up-regulates the expressions of PR1, PR2, and PR5 in response to drought stress, and its transactivation activity is enhanced by CPK11.
拟南芥 Di19（干旱诱导）基因家族编码七个 Cys2/His2 型锌指蛋白，大多数具有未知功能。在这里，我们报告说，Di19 作为转录调节剂，通过上调与发病相关的 PR1、PR2 和 PR5 基因的表达，参与拟南芥对干旱胁迫的反应。Di19 T-DNA 插入突变体 di19 对干旱胁迫更敏感，而 Di19 过表达系与野生型植物相比，对干旱胁迫更耐受。Di19 在我们的酵母测定中表现出转录激活活性，并且其转录激活活性在体内进一步得到证实。DNA 结合分析表明，Di19 可以结合 TACA(A/G)T 元件，染色质免疫沉淀（ChIP）实验表明，Di19 可以结合 PR1、PR2 和 PR5 启动子内的 TACA(A/G)T 元件。qRT-PCR 结果表明，Di19 促进了 PR1、PR2 和 PR5 的表达，并且这些表达的增强作用是由 CPK11 增强的，CPK11 在核内与 Di19 相互作用。与 Di19 过表达系类似，PR1、PR2 和 PR5 过表达系也表现出耐旱表型。水杨酸类似物 INA 的预处理可以增强植物的耐旱性。综上所述，这些数据表明，Di19 作为一种新型转录因子，直接上调 PR1、PR2 和 PR5 的表达，以响应干旱胁迫，其转录激活活性由 CPK11 增强。
