GAMS-1 - A GAMETOPHYTIC MALE-STERILE MUTANT IN MAIZE

Several pollen-specific genes from different species have been isolate d and characterized at the molecular level, but the precise role of mo st of them is unknown. Mutant analysis represents a direct approach to uncovering gene function, but the paucity of available mutants affect ing pollen development and/or function and the poor characterization o f the known mutants have so far limited the exploitation of this appro ach. Here we present the cytological characterization of gametophytic male sterile-1 (gaMS-1), a maize mutant that we identified in a progra m of transposon insertion mutagenesis for the production of mutations in gametophytically acting genes involved in microsporogenesis. gaMS-1 is expressed during or immediately after the first microspore divisio n and leads to the production of immature, nonfunctional pollen grains . The mutation appears to affect the events leading to the development al switch that follows the first microspore mitosis.