MPH1 is a thylakoid membrane protein involved in protecting photosystem II from photodamage in land plants.
Photosystem II (PSII) is highly susceptible to photoinhibition caused by environmental stimuli such as high light; therefore plants have evolved multifaceted mechanisms to efficiently protect PSII from photodamage. We previously published data suggesting that Maintenance of PSII under High light 1 (MPH1, encoded by AT5G07020), a PSII-associated proline-rich protein found in land plants, participates in the maintenance of normal PSII activity under photoinhibitory stress. Here we provide additional evidence for the role of MPH1 in protecting PSII against photooxidative damage. Two Arabidopsis thaliana mutants lacking a functional MPH1 gene suffer from severe photoinhibition relative to the wild-type plants under high irradiance light. The mph1 mutants exhibit significantly decreased PSII quantum yield and electron transport rate after exposure to photoinhibitory light. The mutants also display drastically elevated photodamage to PSII reaction center proteins after high-light treatment. These data add further evidence that MPH1 is involved in PSII photoprotection in Arabidopsis. MPH1 homologs are found across phylogenetically diverse land plants but are not detected in algae or prokaryotes. Taken together, these results suggest that MPH1 protein began to play a role in protecting PSII against excess light following the transition from aquatic to terrestrial conditions.
a Department of Biochemistry and Molecular Biology ; Michigan State University ; East Lansing , MI USA.
Jun
J
Liu
a Department of Biochemistry and Molecular Biology ; Michigan State University ; East Lansing , MI USA.|b Department of Plant Biology ; Michigan State University ; East Lansing , MI USA.
Robert L
RL
Last
D000222:Adaptation, Physiological; D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism / Q000528:radiation effects; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D005075:Biological Evolution; D004579:Electron Transport; D019669:Embryophyta; D017343:Genes, Plant; D008027:Light; D009154:Mutation; D010766:Phosphorylation; D010788:Photosynthesis; D045332:Photosystem II Protein Complex / Q000378:metabolism*; D013312:Stress, Physiological; D060431:Thylakoid Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D020524:Thylakoids / Q000378:metabolism
D029681:Arabidopsis Proteins; C000607350:MPH1 protein, Arabidopsis; D045332:Photosystem II Protein Complex; D060431:Thylakoid Membrane Proteins
PSII damage; PSII repair cycle; Photosystem II; high light; land plants; photoinhibition; thylakoid membranes