Abstract
An Arabidopsis mutant named short stem and midrib(ssm) shows a semi-dwarf phenotype. We identified the mutant gene by chromosome walking and found that it encodes a syntaxin SYP23/AtVAM3, which is localized on the vacuolar membrane. In the ssm mutant, the sixth intron of the SYP22/AtVAM3 gene is partially deleted. We found that the resulting intron sequence was not spliced and translated to 19 amino acids between the 6th exon (which encodes juxtamembrane domain) and the 7th exon (which encodes transmembrane domain).
Knockout mutants of SYP22/AtVAM3 are known to be gametophyte lethal. Further studies on the ssm mutant will provide a new clue for elucidating the function of plant syntaxin-related proteins.
