Guangxin Ji, Zheyuan Wang, Jiaqi Song, Hongrui Zhang, Kexin Wang, Jingjing Xu, Nan Sun, Tanhang Zhang, Siyue Qi, Changjun Ding, Huihui Zhang
Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, Ministry of Education, College of Life Sciences, Northeast Forestry University, No. 26 Hexing Road, Xiangfang District, Harbin 150040, China.
State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, No. 1, Dongxiaofu, Xiangshan Road, Haidian District, Beijing 100091, China.
Tree Physiol. 2025 Jan 25;45(1). doi: 10.1093/treephys/tpaf004.
Understanding drought resistance mechanisms is crucial for breeding poplar species suited to arid and semiarid regions. This study explored the drought responses of three newly developed 'Zhongxiong' series poplars using integrated transcriptomic and physiological analyses. Under drought stress, poplar leaves showed significant changes in differentially expressed genes linked to photosynthesis-related pathways, including photosynthesis-antenna proteins and carbon fixation, indicating impaired photosynthetic function and carbon assimilation. Additionally, drought stress triggered oxidative damage through increased reactive oxygen species production, leading to malondialdehyde accumulation. Weighted gene co-expression network analysis revealed that differentially expressed genes closely associated with physiological responses were enriched in cell redox homeostasis pathways, specifically the thioredoxin-peroxiredoxin pathway. Key genes in this pathway and in cyclic electron flow, such as PGR5-L1A, were downregulated, suggesting compromised reactive oxygen species scavenging and photoprotection under drought stress. Notably, ZX4 poplar exhibited higher drought tolerance, maintaining stronger activity in cyclic electron flow and the thioredoxin-peroxiredoxin pathway compared with ZX3 and ZX5. Genes like PGR5-L1A, 2-Cys Prx BAS1, PrxQ and TPX are promising candidates for enhancing drought resistance in poplars through genetic improvement, with potential applications for developing resilient forestry varieties.
了解抗旱机制对于培育适合干旱和半干旱地区的杨树品种至关重要。本研究通过整合转录组学和生理学分析，探索了三个新培育的“中雄”系列杨树的干旱响应。在干旱胁迫下，杨树叶片中与光合作用相关途径（包括光合作用天线蛋白和碳固定）相关的差异表达基因发生了显著变化，这表明光合功能和碳同化受到损害。此外，干旱胁迫通过增加活性氧的产生引发氧化损伤，导致丙二醛积累。加权基因共表达网络分析表明，与生理反应密切相关的差异表达基因在细胞氧化还原稳态途径中富集，特别是硫氧还蛋白-过氧化物酶途径。该途径以及循环电子流中的关键基因，如PGR5-L1A，表达下调，这表明在干旱胁迫下活性氧清除和光保护能力受损。值得注意的是，与ZX3和ZX5相比，ZX4杨树表现出更高的耐旱性，在循环电子流和硫氧还蛋白-过氧化物酶途径中保持更强的活性。像PGR5-L1A、2-半胱氨酸过氧化物酶BAS1、PrxQ和TPX这样的基因有望通过基因改良提高杨树的抗旱性，在培育抗逆性林业品种方面具有潜在应用价值。
