title: Developmental defects in mutants of the PsbP domain protein 5 in Arabidopsis thaliana.
abstract: Plants contain an extensive family of PsbP-related proteins termed PsbP-like (PPL) and PsbP domain (PPD) proteins, which are localized to the thylakoid lumen. The founding member of this family, PsbP, is an established component of the Photosystem II (PS II) enzyme, and the PPL proteins have also been functionally linked to other photosynthetic processes. However, the functions of the remaining seven PPD proteins are unknown. To elucidate the function of the PPD5 protein (At5g11450) in Arabidopsis, we have characterized a mutant T-DNA insertion line (SALK_061118) as well as several RNAi lines designed to suppress the expression of this gene. The functions of the photosynthetic electron transfer reactions are largely unaltered in the ppd5 mutants, except for a modest though significant decrease in NADPH dehydrogenase (NDH) activity. Interestingly, these mutants show striking plant developmental and morphological defects. Relative to the wild-type Col-0 plants, the ppd5 mutants exhibit both increased lateral root branching and defects associated with axillary bud formation. These defects include the formation of additional rosettes originating from axils at the base of the plant as well as aerial rosettes formed at the axils of the first few nodes of the shoot. The root-branching phenotype is chemically complemented by treatment with the synthetic strigolactone, GR24. We propose that the developmental defects observed in the ppd5 mutants are related to a deficiency in strigolactone biosynthesis.
authors.affiliation: Department of Biological Sciences, Biochemistry and Molecular Biology Section, Louisiana State University, Baton Rouge, Louisiana, United States of America. jroose@lsu.edu
authors.forename: Johnna L
authors.initials: JL
authors.lastname: Roose
authors.forename: Laurie K
authors.initials: LK
authors.lastname: Frankel
authors.forename: Terry M
authors.initials: TM
authors.lastname: Bricker
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D002734:Chlorophyll / Q000378:metabolism; D005453:Fluorescence; D018506:Gene Expression Regulation, Plant; D005816:Genetic Complementation Test; D005820:Genetic Testing; D009154:Mutation / Q000235:genetics*; D010641:Phenotype; D010788:Photosynthesis / Q000235:genetics; D045332:Photosystem II Protein Complex / Q000235:genetics* / Q000378:metabolism; D018517:Plant Roots / Q000254:growth & development; D030821:Plants, Genetically Modified; D034622:RNA Interference; D020524:Thylakoids / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; C571505:PPD5 protein, Arabidopsis; D045332:Photosystem II Protein Complex; D002734:Chlorophyll