Yao Zhen, Rao Zelai, Hou ShuWang, Tian Changwei, Liu Chun-Yan, Yang Xiulan, Zhu Guicai
College of Horticulture and Gardening, Yangtze University, Jingzhou, China.
School of Finance and Economics, Jimei University, Xiamen, China.
Front Plant Sci. 2022 Oct 27;13:999757. doi: 10.3389/fpls.2022.999757. eCollection 2022.
Photorespiration has emerged as a hotspot in the evolution of photosynthesis owing to the energy loss during the process. To ensure the physiological functions of photorespiration such as light protection, HO signaling, and stress resistance, separate the photorespiration glycolic acid flow, and minimize photorespiration loss, a balance must be maintained during the construction of photorespiratory metabolic branch. In this study, glycolate oxidase (GLO) and catalase (CAT) were introduced into potato () chloroplasts through the expression of fusion protein. Through the examination of phenotypic characteristics, photosynthesis, anatomical structure, and enzyme activity, the efficiency of the photorespiration pathway was demonstrated. The results showed that certain transgenic lines plants had shorter plant height and deformed leaves and tubers in addition to the favorable photosynthetic phenotypes of thicker leaves and larger and denser mesophyll cells. By Diaminobenzidine (DAB) staining analysis of the leaves, the intermediate HO could not be decomposed in time to cause biomass decline and malformation, and the excessive glycolate shunt formed by the overexpression of the fusion protein affected other important physiological activities. Hence, the appropriate and coordinated expression of glycolate oxidase and catalase is essential for the establishment of photorespiration pathways in chloroplasts.
由于光呼吸过程中的能量损失,它已成为光合作用进化中的一个热点。为确保光呼吸的生理功能,如光保护、过氧化氢(HO)信号传导和抗逆性,分离光呼吸乙醇酸流动,并使光呼吸损失最小化,在构建光呼吸代谢分支时必须保持平衡。在本研究中,通过融合蛋白表达将乙醇酸氧化酶(GLO)和过氧化氢酶(CAT)导入马铃薯()叶绿体。通过对表型特征、光合作用、解剖结构和酶活性的检测,证明了光呼吸途径的效率。结果表明,某些转基因株系植株除了具有叶片较厚、叶肉细胞更大且更密集的良好光合表型外,还具有株高较短、叶片和块茎畸形的特点。通过对叶片进行二氨基联苯胺(DAB)染色分析,中间产物HO不能及时分解,导致生物量下降和畸形,融合蛋白过表达形成的过量乙醇酸分流影响了其他重要的生理活动。因此,乙醇酸氧化酶和过氧化氢酶的适当和协调表达对于叶绿体中光呼吸途径的建立至关重要。