Institute of Turfgrass Science, Beijing Forestry University, Beijing 100083, China.
Department of Turf Science and Engineering, Sichuan Agricultural University, Chengdu 611130, China.
Int J Mol Sci. 2023 Sep 14;24(18):14070. doi: 10.3390/ijms241814070.
As a typical warm-season grass, bermudagrass growth and turf quality begin to decrease when the environmental temperature drops below 20 °C. The current study investigated the differential responses of three bermudagrass genotypes to chilling stress (8/4 °C) for 15 days and then freezing stress (2/-2 °C) for 2 days. The three genotypes exhibited significant variation in chilling and freezing tolerance, and Chuannong-3, common bermudagrass 001, and Tifdwarf were ranked as cold-tolerant, -intermediate, and -sensitive genotypes based on evaluations of chlorophyll content, the photochemical efficiency of photosystem II, oxidative damage, and cell membrane stability, respectively. Chuannong-3 achieved better tolerance through enhancing the antioxidant defense system to stabilize cell membrane and reactive oxygen species homeostasis after being subjected to chilling and freezing stresses. Chuannong-3 also downregulated the ethylene signaling pathway by improving expression and suppressing the transcript levels of and ; however, it upregulated the hydrogen sulfide signaling pathway via an increase in expression under cold stress. In addition, the molecular basis of cold tolerance could be associated with the mediation of key genes in the heat shock pathway (, , , and ) and the in Chuannong-3 because the accumulation of stress-defensive proteins, including heat shock proteins and osmotin, plays a positive role in osmoprotection, osmotic adjustment, or the repair of denatured proteins as molecular chaperones under cold stress. The current findings give an insight into the physiological and molecular mechanisms of cold tolerance in the new cultivar Chuannong-3, which provides valuable information for turfgrass breeders and practitioners.
作为一种典型的暖季型草，百慕大草的生长和草坪质量在环境温度下降到 20°C 以下时开始下降。本研究调查了三个百慕大草基因型在 15 天的冷胁迫（8/4°C）和随后 2 天的冻胁迫（2/-2°C）下的差异响应。这三个基因型在耐冷性和抗冻性方面表现出显著的差异，根据叶绿素含量、光合作用系统 II 的光化学效率、氧化损伤和细胞膜稳定性的评估，传农 3 号、普通百慕大草 001 和 Tifdwarf 分别被评为耐寒型、中间型和敏感型基因型。传农 3 号通过增强抗氧化防御系统，在受到冷胁迫和冻胁迫后稳定细胞膜和活性氧平衡，从而实现更好的耐受能力。传农 3 号还通过提高表达水平和抑制 和 的转录水平，下调了乙烯信号通路；然而，它通过增加硫化氢信号通路的表达，在冷胁迫下上调了该信号通路。此外，冷胁迫下关键基因（如热休克蛋白、渗透压素等）和脯氨酸代谢通路在传农 3 号中的表达上调，可能与冷耐性的分子基础有关，这些应激防御蛋白的积累，如热休克蛋白和渗透压素，作为分子伴侣在冷胁迫下对蛋白质变性的保护、渗透调节或修复起着积极的作用。本研究结果深入了解了传农 3 号新品种的冷耐性的生理和分子机制，为草坪草育种者和从业者提供了有价值的信息。
