Identification of an allele of VAM3/SYP22 that confers a semi-dwarf phenotype in Arabidopsis thaliana.
The short stem and midrib (ssm) mutants of Arabidopsis thaliana show both semi-dwarf and wavy leaf phenotypes due to defects in the elongation of the stem internodes and leaves. Moreover, these abnormalities cannot be recovered by exogenous phytohormones. ssm was originally identified as a single recessive mutant of the ecotype Columbia (Col-0), but genetic crossing experiments have revealed that this mutant phenotype is restored by another gene that is functional in the ecotype Landsberg erecta (Ler) and not in Col-0. Map-based cloning of the gene that is defective in ssm mutants has uncovered a small deletion in the sixth intron of a gene encoding a syntaxin, VAM3/SYP22, which has been implicated in vesicle transport to the vacuole. This mutation appears to cause a peptide insertion in the deduced VAM3/SYP22 polypeptide sequence due to defective splicing of the shortened sixth intron. Significantly, when compared with the wild-type Ler genome, the wild-type Col-0 genome has a single base pair deletion causing a frameshift mutation in SYP23, a gene with the highest known homology to VAM3/SYP22. These findings suggest that VAM3/SYP22 and SYP23 have overlapping functions and that the vesicle transport mediated by these syntaxins is important for shoot morphogenesis.
Ohtomo
Ichiro
I
Division of Biological Sciences, Graduate School of Science, Hokkaido University, N10 W8, Sapporo, 060-0810 Japan.
Ueda
Haruko
H
Shimada
Tomoo
T
Nishiyama
Chiaki
C
Komoto
Yasuko
Y
Hara-Nishimura
Ikuko
I
Takahashi
Taku
T
D000483:Alleles; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics*; D001483:Base Sequence; D015153:Blotting, Western; D017931:DNA Primers; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D050765:Qa-SNARE Proteins; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid
D029681:Arabidopsis Proteins; D017931:DNA Primers; D008565:Membrane Proteins; D050765:Qa-SNARE Proteins; C108430:Vam3 protein, Arabidopsis