A mutation in Arabidopsis seedling plastid development1 affects plastid differentiation in embryo-derived tissues during seedling growth.
Oilseed plants like Arabidopsis (Arabidopsis thaliana) develop green photosynthetically active embryos. Upon seed maturation, the embryonic chloroplasts degenerate into a highly reduced plastid type called the eoplast. Upon germination, eoplasts redifferentiate into chloroplasts and other plastid types. Here, we describe seedling plastid development1 (spd1), an Arabidopsis seedling albino mutant capable of producing normal green vegetative tissues. Mutant seedlings also display defects in etioplast and amyloplast development. Precocious germination of spd1 embryos showed that the albino seedling phenotype of spd1 was dependent on the passage of developing embryos through the degreening and dehydration stages of seed maturation, suggesting that SPD1 is critical during eoplast development or early stages of eoplast redifferentiation. The SPD1 gene was found to encode a protein containing a putative chloroplast-targeting sequence in its amino terminus and also domains common to P-loop ATPases. Chloroplast localization of the SPD1 protein was confirmed by targeting assays in vivo and in vitro. Although the exact function of SPD1 remains to be defined, our findings reveal aspects of plastid development unique to embryo-derived cells.
Department of Biology, Indiana University, Bloomington, Indiana 47405-2179, USA.
Nicholas J
NJ
Ruppel
Charles A
CA
Logsdon
Craig W
CW
Whippo
Kentaro
K
Inoue
Roger P
RP
Hangarter
D000251:Adenosine Triphosphatases / Q000378:metabolism; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000166:cytology / Q000196:embryology* / Q000235:genetics* / Q000648:ultrastructure; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D048429:Cell Size; D002734:Chlorophyll / Q000378:metabolism; D018548:Cotyledon / Q000166:cytology / Q000378:metabolism; D056426:Genetic Loci / Q000235:genetics; D018522:Gravitropism; D018546:Hypocotyl / Q000502:physiology; D058503:Mesophyll Cells / Q000166:cytology / Q000378:metabolism / Q000648:ultrastructure; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics*; D009928:Organ Specificity; D038081:Organogenesis / Q000235:genetics; D010641:Phenotype; D018087:Plastids / Q000235:genetics* / Q000648:ultrastructure; D021381:Protein Transport; D036226:Seedlings / Q000166:cytology / Q000235:genetics / Q000254:growth & development* / Q000648:ultrastructure; D012639:Seeds / Q000166:cytology / Q000196:embryology* / Q000378:metabolism
D029681:Arabidopsis Proteins; C557635:Spd1 protein, Arabidopsis; D002734:Chlorophyll; D000251:Adenosine Triphosphatases