School of Horticulture and Landscape Architecture, Northeast Agricultural University, Harbin, 150030, China.
Plant Cell Rep. 2024 Jun 19;43(7):176. doi: 10.1007/s00299-024-03261-4.
Saline-alkali stress induces oxidative damage and photosynthesis inhibition in H. citrina, with a significant downregulation of the expression of photosynthesis- and antioxidant-related genes at high concentration. Soil salinization is a severe abiotic stress that impacts the growth and development of plants. In this study, Hemerocallis citrina Baroni was used to investigate its responsive mechanism to complex saline-alkali stress (NaCl:NaSO:NaHCO:NaCO = 1:9:9:1) for the first time. The growth phenotype, photoprotective mechanism, and antioxidant system of H. citrina were studied combining physiological and transcriptomic techniques. KEGG enrichment and GO analyses revealed significant enrichments of genes related to photosynthesis, chlorophyll degradation and antioxidant enzyme activities, respectively. Moreover, weighted gene co-expression network analysis (WGCNA) found that saline-alkali stress remarkably affected the photosynthetic characteristics and antioxidant system. A total of 29 key genes related to photosynthesis and 29 key genes related to antioxidant enzymes were discovered. High-concentration (250 mmol L) stress notably inhibited the expression levels of genes related to light-harvesting complex proteins, photosystem reaction center activity, electron transfer, chlorophyll synthesis, and Calvin cycle in H. citrina leaves. However, most of them were insignificantly changed under low-concentration (100 mmol L) stress. In addition, H. citrina leaves under saline-alkali stress exhibited yellow-brown necrotic spots, increased cell membrane permeability and accumulation of reactive oxygen species (ROS) as well as osmolytes. Under 100 mmol L stress, ROS was eliminate by enhancing the activities of antioxidant enzymes. Nevertheless, 250 mmol L stress down-regulated the expression levels of genes encoding antioxidant enzymes, and key enzymes in ascorbate-glutathione (AsA-GSH) cycle as well as thioredoxin-peroxiredoxin (Trx-Prx) pathway, thus inhibiting the activities of these enzymes. In conclusion, 250 mmol L saline-alkali stress caused severe damage to H. citrina mainly by inhibiting photosynthesis and ROS scavenging capacity.
盐碱胁迫诱导黄菖蒲叶片氧化损伤和光合作用抑制，高浓度下光合作用和抗氧化相关基因表达显著下调。土壤盐渍化是一种严重的非生物胁迫，影响植物的生长和发育。本研究首次利用黄菖蒲来研究其对复杂盐碱胁迫（NaCl:NaSO:NaHCO:NaCO=1:9:9:1）的响应机制。结合生理和转录组学技术，研究了黄菖蒲的生长表型、光保护机制和抗氧化系统。KEGG 富集和 GO 分析分别揭示了与光合作用、叶绿素降解和抗氧化酶活性相关的基因显著富集。此外，加权基因共表达网络分析（WGCNA）发现，盐碱胁迫显著影响了光合作用特征和抗氧化系统。共发现 29 个与光合作用相关的关键基因和 29 个与抗氧化酶相关的关键基因。高浓度（250mmolL）胁迫显著抑制了黄菖蒲叶片中光捕获复合物蛋白、光系统反应中心活性、电子传递、叶绿素合成和卡尔文循环相关基因的表达水平。然而，在低浓度（100mmolL）胁迫下，它们中的大多数变化不显著。此外，黄菖蒲叶片在盐碱胁迫下出现黄棕色坏死斑点，细胞膜通透性增加，活性氧（ROS）和渗透物质积累。在 100mmolL 胁迫下，ROS 通过增强抗氧化酶的活性得以消除。然而，在 250mmolL 胁迫下，抗氧化酶编码基因的表达水平下调，以及抗坏血酸-谷胱甘肽（AsA-GSH）循环和硫氧还蛋白-过氧化物酶（Trx-Prx）途径中的关键酶下调，从而抑制这些酶的活性。综上所述，250mmolL 盐碱胁迫主要通过抑制光合作用和 ROS 清除能力对黄菖蒲造成严重损伤。
