Mitochondrial GFA2 is required for synergid cell death in Arabidopsis.
Little is known about the molecular processes that govern female gametophyte (FG) development and function, and few FG-expressed genes have been identified. We report the identification and phenotypic analysis of 31 new FG mutants in Arabidopsis. These mutants have defects throughout development, indicating that FG-expressed genes govern essentially every step of FG development. To identify genes involved in cell death during FG development, we analyzed this mutant collection for lines with cell death defects. From this analysis, we identified one mutant, gfa2, with a defect in synergid cell death. Additionally, the gfa2 mutant has a defect in fusion of the polar nuclei. We isolated the GFA2 gene and show that it encodes a J-domain-containing protein. Of the J-domain-containing proteins in Saccharomyces cerevisiae (budding yeast), GFA2 is most similar to Mdj1p, which functions as a chaperone in the mitochondrial matrix. GFA2 is targeted to mitochondria in Arabidopsis and partially complements a yeast mdj1 mutant, suggesting that GFA2 is the Arabidopsis ortholog of yeast Mdj1p. These data suggest a role for mitochondria in cell death in plants.
Christensen
Cory A
CA
Department of Biology, University of Utah, Salt Lake City, Utah 84112-0840, USA.
Gorsich
Steven W
SW
Brown
Ryan H
RH
Jones
Linda G
LG
Brown
Jessica
J
Shaw
Janet M
JM
Drews
Gary N
GN
D000595:Amino Acid Sequence; D017209:Apoptosis / Q000235:genetics / Q000502:physiology*; D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D004926:Escherichia coli / Q000235:genetics; D005298:Fertility / Q000502:physiology; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D005816:Genetic Complementation Test; D050956:HSP40 Heat-Shock Proteins; D006360:Heat-Shock Proteins / Q000235:genetics; D008565:Membrane Proteins / Q000235:genetics; D008928:Mitochondria / Q000378:metabolism*; D018832:Molecular Chaperones / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D012441:Saccharomyces cerevisiae / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins; D012639:Seeds / Q000166:cytology / Q000235:genetics*; D017386:Sequence Homology, Amino Acid
D029681:Arabidopsis Proteins; C469262:GFA2 protein, Arabidopsis; D050956:HSP40 Heat-Shock Proteins; D006360:Heat-Shock Proteins; C087041:MDJ1 protein, S cerevisiae; D008565:Membrane Proteins; D018832:Molecular Chaperones; D029701:Saccharomyces cerevisiae Proteins