title: Overexpression of monoubiquitin improves photosynthesis in transgenic tobacco plants following high temperature stress.
abstract: The ubiquitin/26S proteasome system (Ub/26S) is implicated in abiotic stress responses in plants. In this paper, transgenic tobacco plants overexpressing Ta-Ub2 from wheat were used to study the functions of Ub in the improvement of photosynthesis under high temperature (45°C) stress. We observed higher levels of Ub conjugates in transgenic plants under high temperature stress conditions compared to wild type (WT) as a result of the constitutive overexpression of Ta-Ub2, suggesting increased protein degradation by the 26S proteasome system under high temperature stress. Overexpressing Ub increased the photosynthetic rate (Pn) of transgenic tobacco plants, consistent with the improved ATPase activity in the thylakoid membrane and enhanced efficiency of PSII photochemistry. The higher D1 protein levels following high temperature stress in transgenic plants than WT were also observed. These findings imply that Ub may be involved in tolerance of photosynthesis to high temperature stress in plants. Compared with WT, the transgenic plants showed lower protein carbonylation and malondialdehyde (MDA) levels, less reactive oxygen species (ROS) accumulation, but higher antioxidant enzyme activity under high temperature stress. These findings suggest that the improved antioxidant capacity of transgenic plants may be one of the most important mechanisms underlying Ub-regulated high temperature tolerance.
authors.affiliation: State Key Laboratory of Crop Biology, Shandong Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, 61 Daizong Street, Tai'an 271018, China; College of Life Science and Technology, Nanyang Normal University, 1638 Wolong Road, Nanyang 473061, China.
authors.forename: Fengxia
authors.initials: F
authors.lastname: Tian
authors.affiliation: State Key Laboratory of Crop Biology, Shandong Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, 61 Daizong Street, Tai'an 271018, China.
authors.forename: Jiangfeng
authors.initials: J
authors.lastname: Gong
authors.affiliation: State Key Laboratory of Tree Genetics and Breeding, Research Institute of Forestry, Chinese Academy of Forestry, 8 Xiangshan Road, Beijing 100091, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Crop Biology, Shandong Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, 61 Daizong Street, Tai'an 271018, China.
authors.forename: Yanan
authors.initials: Y
authors.lastname: Feng
authors.affiliation: State Key Laboratory of Crop Biology, Shandong Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, 61 Daizong Street, Tai'an 271018, China.
authors.forename: Guokun
authors.initials: G
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Crop Biology, Shandong Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, 61 Daizong Street, Tai'an 271018, China.
authors.forename: Qifang
authors.initials: Q
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Crop Biology, Shandong Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, 61 Daizong Street, Tai'an 271018, China. Electronic address: wangw@sdau.edu.cn.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
mesh_terms: D004553:Electric Conductivity; D006358:Hot Temperature; D015227:Lipid Peroxidation; D010788:Photosynthesis; D045332:Photosystem II Protein Complex / Q000378:metabolism; D018515:Plant Leaves / Q000378:metabolism; D030821:Plants, Genetically Modified; D050050:Protein Carbonylation; D017382:Reactive Oxygen Species / Q000378:metabolism; D013312:Stress, Physiological; D020524:Thylakoids / Q000378:metabolism; D014026:Nicotiana / Q000378:metabolism*; D014908:Triticum / Q000235:genetics; D025801:Ubiquitin / Q000235:genetics / Q000378:metabolism*
chemical_list: D045332:Photosystem II Protein Complex; D017382:Reactive Oxygen Species; D025801:Ubiquitin
keywords: Antioxidant competence; High temperature stress; Photosynthesis; Thylakoid membrane protein; Ubiquitin