Xu Juanjuan, Du Ni, Dong Tianci, Zhang Han, Xue Tao, Zhao Fei, Zhao Fenglan, Duan Yongbo, Xue Jianping
Anhui Provincial Engineering Laboratory for Efficient Utilization of Featured Resource Plants, College of Life Sciences, Huaibei Normal University, Huaibei, Anhui, China.
College of Agronomy & Resources and Environment, Tianjin Agricultural University, Tianjin, China.
Front Plant Sci. 2023 Oct 2;14:1206798. doi: 10.3389/fpls.2023.1206798. eCollection 2023.
Drought is one of the major abiotic stresses limiting agricultural production, particularly for shallow-rooted plants like . It damages plants via oxidative burst, but this effect could be mitigated by catalase (CAT). However, no studies have been reported on CAT homologs in , a drought-sensitive plant species. In the present study, a novel CAT gene, , was functionally characterized via overexpression in and analysis of cis-elements in its promoter. The isolated CAT gene was 1479 bp and encoded a protein containing 242 amino acids. The protein contains the CAT activity motif and the heme-binding site of a typical CAT, and the subcellular analysis indicated that the protein localizes at the cytoplasm and membrane. Moreover, the quantitative real-time reverse transcription PCR indicated that is expressed ubiquitously in and is strongly induced by drought stress and abscisic acid (ABA) signals. overexpression enhanced the drought tolerance of , as shown by the 30% increase in plant survival and a five-fold- increase in CAT activity. Moreover, -transgenic plants increased superoxide dismutase and peroxidase activities and reduced malondialdehyde, membrane leakage, and hydrogen peroxide (HO) (<0.05). Furthermore, -transgenic plants showed higher tolerance to oxidative stress caused by exogenous HO and retained higher chlorophyll and water contents than the WT. The mitochondria function was better maintained as presented by the higher oxygen consumption rate in transgenics under drought stress (<0.05). The endogenous and drought response-related genes were also upregulated in transgenic lines under drought stress, indicating that confers drought stress tolerance by enhancing the HO scavenging ability of plants to maintain their membrane integrity. These results improve our understanding of the drought response mechanisms and provide a potential breeding strategy for genetic improvement.
干旱是限制农业生产的主要非生物胁迫之一，对于像[具体植物名称未给出]这样的浅根植物尤其如此。它通过氧化爆发损害植物，但过氧化氢酶（CAT）可以减轻这种影响。然而，尚未有关于干旱敏感植物物种[具体植物名称未给出]中CAT同源物的研究报道。在本研究中，通过在[具体植物名称未给出]中过表达以及对其启动子中的顺式元件进行分析，对一个新的CAT基因[具体基因名称未给出]进行了功能鉴定。分离得到的CAT基因长度为1479 bp，编码一个含有242个氨基酸的蛋白质。该蛋白质包含典型CAT的CAT活性基序和血红素结合位点，亚细胞分析表明该蛋白质定位于细胞质和膜上。此外，定量实时逆转录PCR表明[具体基因名称未给出]在[具体植物名称未给出]中普遍表达，并受到干旱胁迫和脱落酸（ABA）信号的强烈诱导。[具体基因名称未给出]过表达增强了[具体植物名称未给出]的耐旱性，表现为植物存活率提高30%，CAT活性增加五倍。此外，[具体基因名称未给出]转基因植物的超氧化物歧化酶和过氧化物酶活性增加，丙二醛、膜透性和过氧化氢（H₂O₂）含量降低（P<0.05）。此外，[具体基因名称未给出]转基因植物对外源H₂O₂引起的氧化胁迫表现出更高的耐受性，并且比野生型保留更高的叶绿素和水分含量。干旱胁迫下转基因植物的氧气消耗率更高，表明线粒体功能得到更好的维持（P<0.05）。干旱胁迫下转基因株系中内源[具体基因名称未给出]和干旱响应相关基因也上调，表明[具体基因名称未给出]通过增强植物清除H₂O₂的能力以维持其膜完整性来赋予干旱胁迫耐受性。这些结果增进了我们对干旱响应机制的理解，并为[具体植物名称未给出]的遗传改良提供了一种潜在的育种策略。
