caa a22 4500 606209190 CHVBK 20210128101027.0 cr unu---uuuuu 210128e20150401xx s 000 0 eng 10.1007/s00425-014-2231-y doi (NATIONALLICENCE)springer-10.1007/s00425-014-2231-y Role of the mitochondrial alternative oxidase pathway in hydrogen photoproduction in Chlorella protothecoides [Elektronische Daten] [Litao Zhang, Meilin He, Jianguo Liu, Ling Li] Main conclusion : The AOX pathway in C. protothecoides plays an important role in the photoprotection of PSII by alleviating the inhibition of the repair of the photodamaged PSII during H2 photoproduction. We had demonstrated that nitrogen limitation (LN) substantially enhanced H2 photoproduction in Chlorella protothecoides. In the present study, the mitochondrial alternative oxidase (AOX) pathway capacity was found to increase significantly during H2 photoproduction under LN or under LN simultaneously with sulfur deprivation (LNS) conditions. The purpose of this study was to clarify the role of the AOX pathway during H2 photoproduction in C. protothecoides. The AOX pathway can affect H2 photoproduction in the following ways: (1) consuming O2, which is favorable for the establishment of anaerobiosis; (2) consuming NADPH and competing with hydrogenase for photosynthetic electrons, which would decrease the H2 photoproduction; (3) protecting photosystem (PS) II, which is a direct electron source for H2 photoproduction, from photoinhibition. In LN and LNS cultures, the inhibition of the AOX pathway reduced the H2 photoproduction significantly, and did not increase the amount of O2. But, the inhibition of the AOX pathway decreased the maximal photochemical efficiency of PSII (F v/F m) and the actual photochemical efficiency of PSII (Φ PSII) significantly, leading to photoinhibition, which would decrease the photosynthetic electrons transferred to hydrogenase. And, the inhibition of the AOX pathway did not change the level of photoinhibition in the presence of D1 protein synthesis inhibitor chloramphenicol, indicating that the inhibition of the AOX pathway did not accelerate the photodamage to PSII directly but inhibited the repair of the photodamaged PSII. Therefore, the mitochondrial AOX pathway in C. protothecoides plays an important role in the photoprotection of PSII by alleviating the inhibition of the repair of the photodamaged PSII during H2 photoproduction, which is thus able to supply more electrons to hydrogenase under LN and LNS conditions. Springer-Verlag Berlin Heidelberg, 2014 Alternative oxidase nationallicence H2 photoproduction nationallicence Nitrogen limitation nationallicence Photodamage nationallicence Photosynthesis nationallicence AOX : Alternative oxidase nationallicence CEF-I : Cyclic electron flow around PSI nationallicence COX : Cytochrome oxidase nationallicence Fd : Ferredoxin nationallicence F v/ F m : Maximal photochemical efficiency of PSII nationallicence H2 : Hydrogen nationallicence LN : Nitrogen limitation nationallicence LNS : Nitrogen limitation and sulfur deprivation nationallicence N : Nitrogen nationallicence O2 : Oxygen nationallicence PS : Photosystem nationallicence ROS : Reactive oxygen species nationallicence S : Sulfur nationallicence SHAM : Salicylhydroxamic acid nationallicence Φ PSII : Actual photochemical efficiency of PSII nationallicence Zhang Litao National and Local Joint Engineering Laboratory of Ecological Mariculture, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, 266071, Qingdao, Shandong, People's Republic of China aut He Meilin National and Local Joint Engineering Laboratory of Ecological Mariculture, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, 266071, Qingdao, Shandong, People's Republic of China aut Liu Jianguo National and Local Joint Engineering Laboratory of Ecological Mariculture, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, 266071, Qingdao, Shandong, People's Republic of China aut Li Ling National and Local Joint Engineering Laboratory of Ecological Mariculture, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, 266071, Qingdao, Shandong, People's Republic of China aut Planta Springer Berlin Heidelberg 241/4(2015-04-01), 1005-1014 0032-0935 241:4<1005 2015 241 425 https://doi.org/10.1007/s00425-014-2231-y text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00425-014-2231-y text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Zhang Litao National and Local Joint Engineering Laboratory of Ecological Mariculture, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, 266071, Qingdao, Shandong, People's Republic of China aut NATIONALLICENCE 700 1- He Meilin National and Local Joint Engineering Laboratory of Ecological Mariculture, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, 266071, Qingdao, Shandong, People's Republic of China aut NATIONALLICENCE 700 1- Liu Jianguo National and Local Joint Engineering Laboratory of Ecological Mariculture, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, 266071, Qingdao, Shandong, People's Republic of China aut NATIONALLICENCE 700 1- Li Ling National and Local Joint Engineering Laboratory of Ecological Mariculture, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, 266071, Qingdao, Shandong, People's Republic of China aut NATIONALLICENCE 773 0- Planta Springer Berlin Heidelberg 241/4(2015-04-01), 1005-1014 0032-0935 241:4<1005 2015 241 425