Zhang Mengru, Liu Zhaoyang, Fan Yiting, Liu Chaorui, Wang Hairui, Li Yan, Xin Youchao, Gai Yingping, Ji Xianling
State Key Laboratory of Crop Biology, Shandong Agricultural University, Taian 271018, China.
College of Forestry, Shandong Agricultural University, Taian 271018, China.
Genes (Basel). 2022 Mar 12;13(3):501. doi: 10.3390/genes13030501.
Gamma-aminobutyric acid (GABA) has been reported to accumulate in plants when subjected to salt stress, and GABA-transaminase (GABA-T) is the main GABA-degrading enzyme in the GABA shunt pathway. So far, the salt tolerance mechanism of the gene behind the GABA metabolism remains unclear. In this study, the cDNA (designated ) of gene was cloned from mulberry, and our data showed that MuGABA-T protein shares some conserved characteristics with its homologs from several plant species. gene was constitutively expressed at different levels in mulberry tissues, and was induced substantially by NaCl, ABA and SA. In addition, our results demonstrated that exogenous application of GABA significantly reduced the salt damage index and increased plant resistance to NaCl stress. We further performed a functional analysis of gene and demonstrated that the content of GABA was reduced in the transgenic plants, which accumulated more ROS and exhibited more sensitivity to salt stress than wild-type plants. However, exogenous application of GABA significantly increased the activities of antioxidant enzymes and alleviated the active oxygen-related injury of the transgenic plants under NaCl stress. Moreover, the gene was overexpressed in the mulberry hairy roots, and similar results were obtained for sensitivity to salt stress in the transgenic mulberry plants. Our results suggest that the gene plays a pivotal role in GABA catabolism and is responsible for a decrease in salt tolerance, and it may be involved in the ROS pathway in the response to salt stress. Taken together, the information provided here is helpful for further analysis of the function of genes, and may promote mulberry resistance breeding in the future.
据报道，γ-氨基丁酸（GABA）在植物遭受盐胁迫时会积累，而GABA转氨酶（GABA-T）是GABA分流途径中主要的GABA降解酶。到目前为止，GABA代谢背后基因的耐盐机制仍不清楚。在本研究中，从桑树中克隆了该基因的cDNA（命名为 ），我们的数据表明，MuGABA-T蛋白与其来自几种植物物种的同源物具有一些保守特征。该基因在桑树组织中以不同水平组成型表达，并受到NaCl、ABA和SA的显著诱导。此外，我们的结果表明，外源施用GABA显著降低了盐害指数，提高了植物对NaCl胁迫的抗性。我们进一步对该基因进行了功能分析，结果表明，转基因 植物中GABA含量降低，积累了更多的活性氧，并且比野生型植物对盐胁迫更敏感。然而，外源施用GABA显著提高了抗氧化酶的活性，减轻了NaCl胁迫下转基因植物的活性氧相关损伤。此外，该基因在桑树毛状根中过表达，转基因桑树植物对盐胁迫的敏感性也得到了类似的结果。我们的结果表明，该基因在GABA分解代谢中起关键作用，导致耐盐性降低，并且可能参与了盐胁迫响应中的活性氧途径。综上所述，本文提供的信息有助于进一步分析该基因的功能，并可能在未来促进桑树抗性育种。
