title: G6PDH activity highlights the operation of the cyclic electron flow around PSI in Physcomitrella patens during salt stress.
abstract: Photosynthetic performances and glucose-6-phosphate dehydrogenase (G6PDH) activity in Physcomitrella patens changed greatly during salt stress and recovery. In P. patens, the cyclic electron flow around photosystem (PS) I was much more tolerant to high salt stress than PSII. After high salt stress, the PSII activity recovered much more slowly than that of PSI, which was rapidly restored to pretreatment levels even as PSII was almost inactivate. This result suggested that after salt stress the recovery of the cyclic electron flow around PSI was independent of PSII activity. In addition, G6PDH activity and NADPH content increased under high salt stress. When G6PDH activity was inhibited by glucosamine (Glucm, a G6PDH inhibitor), the cyclic electron flow around PSI and the NADPH content decreased significantly. Additionally, after recovery in liquid medium containing Glucm, the PSI activity was much lower than in liquid medium without Glucm. These results suggested the PSI activity was affected significantly by G6PDH activity and the NADPH content. Based on the above results, we propose that G6PDH in P. patens has a close relationship with the photosynthetic process, possibly providing NADPH for the operation of the cyclic electron flow around PSI during salt stress and promoting the restoration of PSI.
authors.affiliation: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China.|Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.
authors.forename: Shan
authors.initials: S
authors.lastname: Gao
authors.affiliation: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China.|Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.|University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Zhenbing
authors.initials: Z
authors.lastname: Zheng
authors.affiliation: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China.|Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.
authors.forename: Li
authors.initials: L
authors.lastname: Huan
authors.affiliation: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China.|Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.
authors.forename: Guangce
authors.initials: G
authors.lastname: Wang
mesh_terms: D019068:Bryopsida / Q000201:enzymology*; D004579:Electron Transport; D005954:Glucosephosphate Dehydrogenase / Q000378:metabolism*; D009249:NADP / Q000378:metabolism; D045331:Photosystem I Protein Complex / Q000378:metabolism*; D045332:Photosystem II Protein Complex / Q000378:metabolism; D054712:Salinity
chemical_list: D045331:Photosystem I Protein Complex; D045332:Photosystem II Protein Complex; D009249:NADP; D005954:Glucosephosphate Dehydrogenase