Li Yingying, Wang Wei, Zhang Na, Cheng Yuxin, Hussain Saddam, Wang Yating, Tian Hainan, Hussain Hadia, Lin Rao, Yuan Yuan, Wang Chen, Wang Tianya, Wang Shucai
Key Laboratory of Molecular Epigenetics of MOE, Northeast Normal University, Changchun 130024, China.
Laboratory of Plant Molecular Genetics & Crop Gene Editing, School of Life Sciences, Linyi University, Linyi 276000, China.
Plants (Basel). 2023 Aug 19;12(16):2989. doi: 10.3390/plants12162989.
The plant hormone ABA (abscisic acid) regulates plant responses to abiotic stresses by regulating the expression of ABA response genes. However, the functions of a large portion of ABA response genes have remained unclear. We report in this study the identification of ASDs (ABA-inducible signal peptide-containing DUF538 proteins), a subgroup of DUF538 proteins with a signal peptide, as the regulators of plant responses to ABA in Arabidopsis. ASDs are encoded by four closely related DUF538 genes, with / and / being two pairs of duplicated tandemly repeated genes. The quantitative RT-PCR (qRT-PCR) results showed that the expression levels of increased significantly in response to ABA as well as NaCl and mannitol treatments, with the exception that the expression level of remained largely unchanged in response to NaCl treatment. The results of Arabidopsis protoplast transient transfection assays showed that ASDs were localized on the plasma membrane and in the cytosol and nucleus. When recruited to the promoter of the reporter gene via a fused GD domain, ASDs were able to slightly repress the expression of the co-transfected reporter gene. Seed germination and cotyledon greening assays showed that ABA sensitivity was increased in the transgenic plants that were over-expressing or but decreased in the transgenic plants that were over-expressing or . On the other hand, ABA sensitivity was increased in the CRISPR/Cas9 gene-edited single mutants but decreased in the single mutants. A transcriptome analysis showed that differentially expressed genes in the transgenic plant seedlings were enriched in several different processes, including in plant growth and development, the secondary metabolism, and plant hormone signaling. In summary, our results show that are ABA response genes and that ASDs are involved in the regulation of plant responses to ABA in Arabidopsis; however, ASD1/ASD3 and ASD2/ASD4 have opposite functions.
植物激素脱落酸（ABA）通过调控ABA响应基因的表达来调节植物对非生物胁迫的反应。然而，大部分ABA响应基因的功能仍不清楚。我们在本研究中报告，鉴定出含ABA诱导信号肽的DUF538蛋白（ASDs），这是DUF538蛋白的一个亚组，带有信号肽，是拟南芥中植物对ABA反应的调节因子。ASDs由四个紧密相关的DUF538基因编码，其中 和 是两对串联重复基因。定量逆转录聚合酶链反应（qRT-PCR）结果表明，除 对NaCl处理的表达水平基本保持不变外， 、 和 的表达水平在ABA以及NaCl和甘露醇处理下显著增加。拟南芥原生质体瞬时转染试验结果表明，ASDs定位于质膜、细胞质和细胞核中。当通过融合的GD结构域被招募到报告基因的启动子时，ASDs能够轻微抑制共转染报告基因的表达。种子萌发和子叶绿化试验表明，过表达 或 的转基因植物中ABA敏感性增加，而过表达 或 的转基因植物中ABA敏感性降低。另一方面，CRISPR/Cas9基因编辑的 单突变体中ABA敏感性增加，而 单突变体中ABA敏感性降低。转录组分析表明， 转基因植物幼苗中的差异表达基因在几个不同过程中富集，包括植物生长发育、次生代谢和植物激素信号传导。总之，我们的结果表明 是ABA响应基因，并且ASDs参与拟南芥中植物对ABA反应的调节；然而，ASD1/ASD3和ASD2/ASD4具有相反的功能。
