Photosystem II (PSII), especially the D1 protein, is highly sensitive to the detrimental impact of heat stress. Photoinhibition always occurs when the rate of photodamage exceeds the rate of D1 protein repair. Here, genetically engineered codA-tomato with the capability to accumulate glycinebetaine (GB) was established. After photoinhibition treatment at high temperature, the transgenic lines displayed more thermotolerance to heat-induced photoinhibition than the control line. GB maintained high expression of LeFtsHs and LeDegs and degraded the damaged D1 protein in time. Meanwhile, the increased transcription of synthesis-related genes accelerated the de novo synthesis of D1 protein. Low ROS accumulation reduced the inhibition of D1 protein translation in the transgenic plants, thereby reducing protein damage. The increased D1 protein content and decreased phosphorylated D1 protein (pD1) in the transgenic plants compared with control plants imply that GB may minimize photodamage and maximize D1 protein stability. As D1 protein exhibits a high turnover, PSII maybe repaired rapidly and efficiently in transgenic plants under photoinhibition treatment at high temperature, with the resultant mitigation of photoinhibition of PSII.

光系统 II (PSII)，尤其是 D1 蛋白，对热应激的不利影响高度敏感。当光损伤速率超过 D1 蛋白修复速率时，总是会发生光抑制。在这里，建立了具有积累甘氨酸甜菜碱 (GB) 能力的基因工程codA-番茄。在高温光抑制处理后，转基因株系比对照株系对热诱导的光抑制表现出更高的耐热性。GB 保持LeFtsHs和LeDegs 的高表达并及时降解受损的D1蛋白。同时，合成相关基因转录的增加加速了D1蛋白的从头合成。低 ROS 积累减少了转基因植物中 D1 蛋白翻译的抑制，从而减少了蛋白质损伤。与对照植物相比，转基因植物中 D1 蛋白含量的增加和磷酸化 D1 蛋白 (pD1) 的降低意味着 GB 可以最大限度地减少光损伤并最大限度地提高 D1 蛋白的稳定性。由于 D1 蛋白表现出高周转率，在高温光抑制处理下，转基因植物中的 PSII 可以快速有效地修复，从而减轻 PSII 的光抑制。