Li Nenghui, Gao Yanqiang, Pu Kaiguo, Zhang Miao, Wang Tiantian, Li Jing, Xie Jianming
College of Horticulture, Gansu Agricultural University, Yingmen Village, Anning District, Lanzhou, 730070, PR China.
College of Horticulture, Gansu Agricultural University, Yingmen Village, Anning District, Lanzhou, 730070, PR China.
Plant Physiol Biochem. 2025 May;222:109705. doi: 10.1016/j.plaphy.2025.109705. Epub 2025 Feb 24.
Glycine betaine (GB) is commonly used as an osmotic regulator and a donor to facilitate changes in methylation in plants and animals, thereby enhancing stress resistance. However, low temperature combined with low light stress represent the most prevalent stresses during pepper growth period in northwest China, and limited studies have focused on the potential stress-mitigating effects of GB. Therefore, to examine the regulatory mechanism of GB-induced tolerance to LL stress, pepper seedlings were pretreated with 20 mmol L GB and 60 μmol L 3-Deazaneplanocin A hydrochloride at a temperature of 10/5 °C and illumination of 100 μmol m s. The results demonstrated that GB significantly alleviated the detrimental effects of low temperature combined with low light stress on growth of primary and lateral roots and increased the roots absorption of mineral nutrients (N, P, Ca, Fe, and Zn). In addition, GB induced the expression of the genes for CaSOD, CaPOD, CaCAT, CaGR1, and CaDHAR, improved osmotic regulation, and increased the activities of enzymatic (superoxide dismutase, peroxidase, catalase, glutathione reductase, and dehydroascorbate reductase) and non-enzymatic antioxidants (ascorbate and glutathione). This resulted in enhanced scavenging of reactive oxygen species, thereby maintaining a balanced oxidation-reduction within the cells. Furthermore, GB substituted S-adenosylmethionine, a partial methylation donor, during the methyl group metabolism process, altering the mA methylation level and increasing the resistance of pepper seedlings to LL stress. Overall, exogenous GB pretreatment could be used as a potential strategy for enhancing the LL tolerance of plants.
甘氨酸甜菜碱（GB）通常用作渗透调节剂和供体，以促进植物和动物甲基化的变化，从而增强抗逆性。然而，低温与弱光胁迫是中国西北地区辣椒生长期间最普遍的胁迫，而针对GB潜在缓解胁迫作用的研究有限。因此，为了研究GB诱导对弱光胁迫耐受性的调控机制，将辣椒幼苗在10/5°C温度和100μmol·m⁻²·s⁻¹光照条件下用20 mmol·L⁻¹GB和60μmol·L⁻¹盐酸3-脱氮杂氮胞苷预处理。结果表明，GB显著减轻了低温与弱光胁迫对主根和侧根生长的不利影响，并增加了根系对矿质营养元素（氮、磷、钙、铁和锌）的吸收。此外，GB诱导了CaSOD、CaPOD、CaCAT、CaGR1和CaDHAR基因的表达，改善了渗透调节作用，并提高了酶促抗氧化剂（超氧化物歧化酶、过氧化物酶、过氧化氢酶、谷胱甘肽还原酶和脱氢抗坏血酸还原酶）和非酶促抗氧化剂（抗坏血酸和谷胱甘肽）的活性。这导致活性氧清除能力增强，从而维持细胞内氧化还原平衡。此外，GB在甲基代谢过程中替代了部分甲基供体S-腺苷甲硫氨酸，改变了mA甲基化水平，提高了辣椒幼苗对弱光胁迫的抗性。总体而言，外源GB预处理可作为提高植物弱光耐受性的潜在策略。
