Betaine aldehyde dehydrogenase polymorphism in spinach: genetic and biochemical characterization.

Spinach (Spinacia oleracea L.) has a major chloroplastic isozyme of betaine aldehyde dehydrogenase (BADH) and a minor cytosolic one. Among a diverse collection of spinach accessions, three electrophoretic banding patterns of chloroplastic BADH were found: two were single banded and one was triple banded. Genetic analysis of these patterns indicated that chloroplastic BADH is encoded by a single, nuclear gene with two alleles, designated slow (S) and fast (F), and that products of these alleles can hybridize to form either homodimers or a heterodimer. The S allele was by far the most common among the accessions examined. Native and sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the SS and FF homodimers differ in charge but not molecular weight.