Molecular genetic analysis of a rice cleistogamy mutant.

Abstract

We identified a cleistogamy mutant of rice harboring a missense mutation in the class B MADS-box gene SUPERWOMAN1 (SPW1), which specifies lodicule (an equivalent of petal) and stamen identities. In this mutant, spw1-cls, stamens are normal but lodicules are transformed homeotically to lodicule-glume mosaic organs, thereby engendering cleistogamy. Introduction of the wild-type SPW1 gene into spw1-cls complemented the lodicule phenotype. Furthermore, introduction of the spw1-cls version of SPW1 (SPW1^cls) into spw1-1, a null allele of spw1, recapitulated the cleistogamy phenotype. We analyzed relationship of SPW1^cls with counterpart class B genes, OsMADS2 and OsMADS4, using yeast two-hybrid assay and in situ hybridization.