Increasing cyclic electron flow is related to Na+ sequestration into vacuoles for salt tolerance in soybean.
In land plants, the NAD(P)H dehydrogenase (NDH) complex reduces plastoquinones and drives cyclic electron flow (CEF) around PSI. It also produces extra ATP for photosynthesis and improves plant fitness under conditions of abiotic environmental stress. To elucidate the role of CEF in salt tolerance of the photosynthetic apparatus, Na(+) concentration, chlorophyll fluorescence, and expression of NDH B and H subunits, as well as of genes related to cellular and vacuolar Na(+) transport, were monitored. The salt-tolerant Glycine max (soybean) variety S111-9 exhibited much higher CEF activity and ATP accumulation in light than did the salt-sensitive variety Melrose, but similar leaf Na(+) concentrations under salt stress. In S111-9 plants, ndhB and ndhH were highly up-regulated under salt stress and their corresponding proteins were maintained at high levels or increased significantly. Under salt stress, S111-9 plants accumulated Na(+) in the vacuole, but Melrose plants accumulated Na(+) in the chloroplast. Compared with Melrose, S111-9 plants also showed higher expression of some genes associated with Na(+) transport into the vacuole and/or cell, such as genes encoding components of the CBL10 (calcineurin B-like protein 10)-CIPK24 (CBL-interacting protein kinase 24)-NHX (Na(+)/H(+) antiporter) and CBL4 (calcineurin B-like protein 4)-CIPK24-SOS1 (salt overly sensitive 1) complexes. Based on the findings, it is proposed that enhanced NDH-dependent CEF supplies extra ATP used to sequester Na(+) in the vacuole. This reveals an important mechanism for salt tolerance in soybean and provides new insights into plant resistance to salt stress.
State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058, China Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, UK.
Yi
Y
He
State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058, China.
Junliang
J
Fu
State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058, China.
Chenliang
C
Yu
State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058, China.
Xiaoman
X
Wang
State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058, China.
Qinsu
Q
Jiang
Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China.
Jian
J
Hong
Laboratory of Plant Molecular Biology, Ningbo University, Ningbo 315211, China.
Kaixing
K
Lu
CSIRO Agriculture Flagship, Queensland 4067, Australia.
Gangping
G
Xue
State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, 310021 Hangzhou, China.
Chengqi
C
Yan
CSIRO Agriculture Flagship, Queensland 4067, Australia.
Andrew
A
James
State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058, China.
Ligen
L
Xu
State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, 310021 Hangzhou, China.
Jianping
J
Chen
State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058, China dajiang@zju.edu.cn.
Dean
D
Jiang
D000255:Adenosine Triphosphate / Q000096:biosynthesis*; D004579:Electron Transport; D058503:Mesophyll Cells / Q000378:metabolism; D009252:NADPH Dehydrogenase / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D055049:Salt Tolerance; D012964:Sodium / Q000378:metabolism*; D013025:Glycine max / Q000235:genetics / Q000502:physiology*; D013312:Stress, Physiological; D014617:Vacuoles / Q000378:metabolism
D010940:Plant Proteins; D000255:Adenosine Triphosphate; D012964:Sodium; D009252:NADPH Dehydrogenase
ATP; CEF; NDH complex; Na+ accumulation; soybean.