Wei Dandan, Zhang Tianpeng, Wang Bingquan, Zhang Huiling, Ma Mingyang, Li Shufen, Chen Tony H H, Brestic Marian, Liu Yang, Yang Xinghong
College of Life Science, State Key Laboratory of Crop Biology, Shandong Key Laboratory of Crop Biology, Shandong Agricultural University, Taian, 271018, Shandong, China.
Xinzhou Teachers University, Xinzhou, 034000, Shanxi, China.
Plant Cell Rep. 2022 Apr;41(4):1087-1101. doi: 10.1007/s00299-022-02839-0. Epub 2022 Feb 12.
Glycinebetaine alleviates chilling stress by protecting photosystems I and II in BADH-transgenic and GB-treated tomato plants, which can be an effective strategy for improving crop chilling tolerance. Tomato (Solanum lycopersicum) is one of the most cultivated vegetables in the world, but is highly susceptible to chilling stress and does not naturally accumulate glycinebetaine (GB), one of the most effective stress protectants. The protective mechanisms of GB on photosystem I (PSI) and photosystem II (PSII) against chilling stress, however, remain poorly understood. Here, we address this problem through exogenous GB application and generation of transgenic tomatoes (Moneymaker) with a gene encoding betaine aldehyde dehydrogenase (BADH), which is the key enzyme in the synthesis of GB, from spinach. Our results demonstrated that GB can protect chloroplast ultramicrostructure, alleviate PSII photoinhibition and maintain PSII stability under chilling stress. More importantly, GB increased the electron transfer between Q and Q and the redox potential of Q and maintained a high rate of cyclic electron flow around PSI, contributing to reduced production of reactive oxygen species, thereby mitigating PSI photodamage under chilling stress. Our results highlight the novel roles of GB in enhancing chilling tolerance via the protection of PSI and PSII in BADH transgenic and GB-treated tomato plants under chilling stress. Thus, introducing GB-biosynthetic pathway into tomato and exogenous GB application are effective strategies for improving chilling tolerance.
甘氨酸甜菜碱通过保护BADH转基因和经甘氨酸甜菜碱处理的番茄植株中的光系统I和光系统II来减轻冷害胁迫，这可能是提高作物耐冷性的一种有效策略。番茄（Solanum lycopersicum）是世界上种植最广泛的蔬菜之一，但对冷害胁迫高度敏感，且不会自然积累甘氨酸甜菜碱（GB），而甘氨酸甜菜碱是最有效的胁迫保护剂之一。然而，关于甘氨酸甜菜碱对光系统I（PSI）和光系统II（PSII）抵御冷害胁迫的保护机制仍知之甚少。在此，我们通过外源施用甘氨酸甜菜碱以及培育转菠菜甜菜碱醛脱氢酶（BADH）基因（该基因是甘氨酸甜菜碱合成中的关键酶）的转基因番茄（Money maker）来解决这一问题。我们的结果表明，甘氨酸甜菜碱可以保护叶绿体超微结构，减轻PSII光抑制，并在冷害胁迫下维持PSII的稳定性。更重要的是，甘氨酸甜菜碱增加了Q和Q之间的电子传递以及Q的氧化还原电位，并维持了围绕PSI的高循环电子流速率，有助于减少活性氧的产生，从而减轻冷害胁迫下PSI的光损伤。我们的结果突出了甘氨酸甜菜碱在冷害胁迫下通过保护BADH转基因和经甘氨酸甜菜碱处理的番茄植株中的PSI和PSII来增强耐冷性方面的新作用。因此，将甘氨酸甜菜碱生物合成途径引入番茄以及外源施用甘氨酸甜菜碱是提高耐冷性的有效策略。
