PDF(Pubmed)
Abstract：
Hairgrass (Deschampsia caespitosa), 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 Δ1-pyrroline-5-carboxylate synthetase, ornithine aminotransferase, Δ1-pyrroline-5-carboxylate reductase, Δ1-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.
摘要：
Hairgrass(Deschampsiaaespitosa),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很有前途，由于持续的气候变化，可能会遭受频繁的干旱和涝灾压力，进一步加剧了该地区草地的退化。然而,它是否会适应极端气候造成的水压力仍然未知。脯氨酸积累是植物对挑战性环境条件的关键代谢反应。本研究旨在调查毛草芽和根组织中脯氨酸积累和关键酶的变化，以响应不同的极端气候，包括中度干旱，中度内涝,和干湿变化超过28天使用完全随机区组设计。脯氨酸的积累，谷氨酸和鸟氨酸途径的贡献，并检查了与芽和根组织中脯氨酸代谢相关的关键酶活性。结果表明，水分胁迫导致毛草芽和根组织中脯氨酸的积累，强调这种渗透保护剂在减轻环境挑战影响方面的重要性。与根部相比，脯氨酸在芽中的积累差异表明植物有战略资源分配以应对渗透胁迫。与脯氨酸代谢相关的酶活性，如Δ1-吡咯啉-5-羧酸合成酶，鸟氨酸转氨酶,Δ1-吡咯啉-5-羧酸还原酶，Δ1-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毛草脯氨酸水平的动态调控。这些发现支持通过脯氨酸生物合成和分解代谢途径的遗传操作来增强发草的抗逆性的潜力。
