Wu Jianqiang, Xie Songmei, Wang Bingjiao, Wang Jian, Jahan Mohammad Shah, Yuan Lingyun, Hou Jinfeng, Chen Guohu, Tang Xiaoyan, Wang Wenjie, Huang Xingxue, Wang Chenggang
Vegetable Genetics and Breeding Laboratory, College of Horticulture, Anhui Agricultural University, Hefei, 230036, China; Wanjiang Vegetable Industrial Technology Institute, Maanshan, 340523, China.
Vegetable Genetics and Breeding Laboratory, College of Horticulture, Anhui Agricultural University, Hefei, 230036, China.
Plant Physiol Biochem. 2025 Aug 15;229(Pt A):110371. doi: 10.1016/j.plaphy.2025.110371.
Wucai is an important specialty vegetable, and its low-temperature tolerance is associated with a polyamine, thermospermine (T-Spm) according to our previous study. However, the mechanism underlying the effect of T-Spm has not been elucidated yet. In this study, we investigated the relationship between T-Spm and cold tolerance of wucai by exogenously applying T-Spm to wucai seedlings exposed to low-temperature stress with water application as control. Under low-temperature condition, seedlings sprayed with water (LT) displayed a significant decrease in the photosynthesis parameters and stunted growth; however, foliar application of T-Spm to the seedlings (LT + T) led to marked increase in the net photosynthetic and transpiration rates, thereby alleviating growth inhibition and wilting phenotype. Compared with LT treatment, the LT + T group experienced simultaneous decrease in the malondialdehyde content, electrolyte leakage and O generation rate by 40.3 %, 51.3 % and 44.0 %, respectively. LT treatment also led to increases in the superoxide dismutase activity and osmotic regulation substance contents, which were increased further after LT + T treatment. The ascorbate peroxidase activity of LT group was obviously declined on the seventh day, whereas that of LT + T treatment was maintained at a higher level, which underscored the role of T-Spm in enhancing antioxidant ability and reducing oxidative damage, eventually contributing to plant photosynthesis and growth. Furthermore, spermidine and T-Spm levels were markedly elevated after three days of LT treatment, and exogenous T-Spm application led to further increase in the content of polyamines, except for spermine. T-Spm treatment also promoted polyamine oxidase activity in response to low temperature, while its effect on the activities of ornithine and arginine decarboxylase was not pronounced; and genes encoding these enzymes showed similar variation trends in their expression, indicating that T-Spm treatment facilitated the homeostasis between PA and proline metabolism. Finally, transcriptome sequencing data revealed that exogenous T-Spm plays a role in regulating the expression of many genes involved in diverse processes, including MAPK signaling, suggesting the mediating role of these signaling pathways in T-Spm-induced cold tolerance.
乌菜是一种重要的特色蔬菜，根据我们之前的研究，其耐低温性与一种多胺——热精胺（T-Spm）有关。然而，T-Spm发挥作用的机制尚未阐明。在本研究中，我们通过向遭受低温胁迫的乌菜幼苗外源施加T-Spm，并以喷水作为对照，研究了T-Spm与乌菜耐冷性之间的关系。在低温条件下，喷水处理的幼苗（LT）光合作用参数显著下降，生长受阻；然而，对幼苗叶面施用T-Spm（LT + T）导致净光合速率和蒸腾速率显著增加，从而减轻了生长抑制和萎蔫表型。与LT处理相比，LT + T组丙二醛含量、电解质渗漏和O产生速率分别同时降低了40.3%、51.3%和44.0%。LT处理还导致超氧化物歧化酶活性和渗透调节物质含量增加，在LT + T处理后进一步增加。LT组的抗坏血酸过氧化物酶活性在第7天明显下降，而LT + T处理的抗坏血酸过氧化物酶活性维持在较高水平，这突出了T-Spm在增强抗氧化能力和减少氧化损伤方面的作用，最终促进植物光合作用和生长。此外，LT处理3天后亚精胺和T-Spm水平显著升高，外源施用T-Spm导致除精胺外的多胺含量进一步增加。T-Spm处理还促进了低温下多胺氧化酶的活性，而其对鸟氨酸和精氨酸脱羧酶活性的影响不明显；编码这些酶的基因在表达上呈现相似的变化趋势，表明T-Spm处理促进了多胺与脯氨酸代谢之间的稳态。最后，转录组测序数据表明，外源T-Spm在调节许多参与不同过程的基因表达中发挥作用，包括MAPK信号传导，表明这些信号通路在T-Spm诱导的耐冷性中起介导作用。
