Luo Qiaoyu, Ma Yonggui, Xie Huichun, Chang Feifei, Guan Chiming, Yang Bing, Ma Yushou
Qinghai Provincial Key Laboratory of Medicinal Plant and Animal Resources of Qinghai-Xizang Plateau, Qinghai Normal University, Xining 810008, China.
School of Life Sciences, Qinghai Normal University, Xining 810008, China.
Plants (Basel). 2024 May 18;13(10):1408. doi: 10.3390/plants13101408.
Hairgrass (), a widely distributed grass species considered promising in the ecological restoration of degraded grassland in the Qinghai-Xizang Plateau, is likely to be subjected to frequent drought and waterlogging stress due to ongoing climate change, further aggravating the degradation of grassland in this region. However, whether it would acclimate to water stresses resulting from extreme climates remains unknown. Proline accumulation is a crucial metabolic response of plants to challenging environmental conditions. This study aims to investigate the changes in proline accumulation and key enzymes in hairgrass shoot and root tissues in response to distinct climate extremes including moderate drought, moderate waterlogging, and dry-wet variations over 28 days using a completely randomized block design. The proline accumulation, contribution of the glutamate and ornithine pathways, and key enzyme activities related to proline metabolism in shoot and root tissues were examined. The results showed that water stress led to proline accumulation in both shoot and root tissues of hairgrass, highlighting the importance of this osmoprotectant in mitigating the effects of environmental challenges. The differential accumulation of proline in shoots compared to roots suggests a strategic allocation of resources by the plant to cope with osmotic stress. Enzymatic activities related to proline metabolism, such as Δ-pyrroline-5-carboxylate synthetase, ornithine aminotransferase, Δ-pyrroline-5-carboxylate reductase, Δ-pyrroline-5-carboxylate dehydrogenase, and proline dehydrogenase, further emphasize the dynamic regulation of proline levels in hairgrass under water stress conditions. These findings support the potential for enhancing the stress resistance of hairgrass through the genetic manipulation of proline biosynthesis and catabolism pathways.
发草（）是一种广泛分布的草种，被认为在青藏高原退化草地的生态恢复中具有潜力。由于气候变化，它可能会频繁遭受干旱和涝渍胁迫，这进一步加剧了该地区草地的退化。然而，它是否能适应极端气候导致的水分胁迫仍不清楚。脯氨酸积累是植物对挑战性环境条件的关键代谢反应。本研究旨在采用完全随机区组设计，研究发草地上部和根部组织中脯氨酸积累和关键酶在28天内对不同极端气候（包括中度干旱、中度涝渍和干湿交替）的响应变化。检测了地上部和根部组织中脯氨酸的积累、谷氨酸和鸟氨酸途径的贡献以及与脯氨酸代谢相关的关键酶活性。结果表明，水分胁迫导致发草地上部和根部组织中脯氨酸积累，突出了这种渗透保护剂在减轻环境挑战影响方面的重要性。地上部与根部脯氨酸的差异积累表明植物为应对渗透胁迫进行了资源的策略性分配。与脯氨酸代谢相关的酶活性，如Δ-吡咯啉-5-羧酸合成酶、鸟氨酸转氨酶、Δ-吡咯啉-5-羧酸还原酶、Δ-吡咯啉-5-羧酸脱氢酶和脯氨酸脱氢酶，进一步强调了水分胁迫条件下发草中脯氨酸水平的动态调节。这些发现支持了通过对脯氨酸生物合成和分解代谢途径进行基因操作来增强发草抗逆性的潜力。
