Abstract
Myrosinases are β-glucosidases that are found mainly in the order Capparales. Myrosinases hydrolyze glucosinolates to produce the toxic compounds for the pests. The abnormal accumulation of myrosinases was found in Arabidopsis mutants of AtVAM3, which is a syntaxin homolog to yeast VAM3 involved in the vacuolar assembly. In this study, we characterized the abnormal accumulation of myrosinases in two AtVAM3 mutants; one expresses the insertion form of AtVAM3 with an additional peptide and another is a knockout mutant of the AtVAM3 gene. The organ specific expression and the localization to the myrosin cells of the myrosinases in these mutants were the same as in wild-type. Interestingly, the numbers of the myrosin cells were markedly increased in the mutants. The abnormal accumulation of myrosinases in the mutants might be caused by the excessive occurrence of the myrosin cells. These results suggest that AtVAM3 is involved in differentiation of myrosin cells.
