Temporal regulation of two cytosolic phosphoglucomutases during stigma development in ornamental kale (Brassica oleracea var. acephala)

Phosphoglucomutases (PGM) (5.4.2.2.) belong to the Phosphohexomutases superfamily and are highly specific in catalyzing the interconversion of Glc-1-P to Glc-6-P. In this study, we characterize the expression and activity of two cytosolic PGMs (cPGM2 and cPGM3) stigmas of ornamental kale during flower development. In stigmas, cPGM expression and activity showed a gradual increase during stigma development with the highest activity around the time of anthesis. Blocking of cPGM activity in the stigmas using a known inhibitor, resulted in breakdown of self-incompatibility in immature S3 and S4 stigmas, but had no effect on the fully mature S5 stigmas. It is likely that cPGMs are required for accumulation of factors necessary for SI response in mature stigmas.