State Key Laboratory of Tree Genetics and Breeding, Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing, 210037, China; National Forestry and Grassland Administration Engineering Research Center for Osmanthus Fragrans, Osmanthus Innovation Center of National Engineering Research Center for Floriculture, Hubei University of Science and Technology, Xianning, 437100, China.
State Key Laboratory of Tree Genetics and Breeding, Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing, 210037, China.
Plant Physiol Biochem. 2024 Nov;216:109152. doi: 10.1016/j.plaphy.2024.109152. Epub 2024 Sep 24.
Stay-green (SGR) genes are pivotal regulatory genes in the context of plant chlorophyll metabolism, but few studies on SGR homologues in Cryptomeria fortunei have been previously reported. We cloned two CfSGR genes and overexpressed them in Arabidopsis to explore their functions. Full-length CfSGR1 and CfSGR2 are 1265 and 1197 bp, encompassing open reading frames (ORFs) encoding 274 and 276 amino acids, respectively. SGRs exhibited high conservation in higher plants, and phylogenetic analysis indicated that SGRs from monocots and gymnosperms cluster in a clade. The proteins localized to chloroplasts and showed no transcriptional activity in yeast cells. The CfSGR gene expressions were induced by abiotic stresses and hormones. Under conditions of darkness, abscisic acid (ABA), salt, drought, or freezing stress, CfSGR2-transgenic Arabidopsis exhibited a delay in leaf yellowing compared to the WT, which was attributed to increased chlorophyll content and enhanced photosynthetic capacity. These transgenic plants exhibited improved resistance to stress via upregulated expression of resistance-related genes, increased antioxidant enzyme activities, and reduced malondialdehyde content and electrolyte leakage rate. In contrast, CfSGR1-transgenic plants may accelerate leaf yellowing and exhibit reduced stress resistance. Our findings highlight potential divergence in the functions of CfSGR genes concerning plant growth and development and responses to abiotic stresses or hormones, providing a scientific foundation for future breeding of stress-resistant C. fortunei cultivars.
SGR 基因在植物叶绿素代谢中是关键的调节基因，但之前关于柳杉 SGR 同源物的研究很少。我们克隆了两个 CfSGR 基因，并在拟南芥中过表达它们，以探索它们的功能。CfSGR1 和 CfSGR2 的全长分别为 1265 和 1197bp，包含分别编码 274 和 276 个氨基酸的开放阅读框 (ORF)。SGR 在高等植物中高度保守，系统发育分析表明单子叶植物和裸子植物的 SGR 聚类在一个分支中。这些蛋白质定位于叶绿体，在酵母细胞中没有转录活性。CfSGR 基因的表达受到非生物胁迫和激素的诱导。在黑暗、脱落酸 (ABA)、盐、干旱或冷冻胁迫条件下，CfSGR2 转基因拟南芥的叶片黄化比 WT 延迟，这归因于叶绿素含量增加和光合作用能力增强。这些转基因植物通过上调抗性相关基因的表达、增加抗氧化酶活性以及降低丙二醛含量和电解质泄漏率来提高对胁迫的抗性。相比之下，CfSGR1 转基因植物可能会加速叶片黄化并降低对胁迫的抗性。我们的研究结果突出了 CfSGR 基因在植物生长发育以及对非生物胁迫或激素的响应方面功能的潜在差异，为未来柳杉抗逆品种的选育提供了科学依据。
