Abstract
Here, we report that RPK2 is a key regulator of anther development in Arabidopsis. RPK2 knockout mutants, rpk2-1 and rdk2-2 displayed male sterility due to defects in anther dehiscence and pollen maturation. In rpk2 anthers, several defects were observed as follows: the middle layer was not differentiated from secondary parietal cells, the tapetum was abnormally enlarged, developmental homeostasis of anther locules was disrupted, most pollen grains highly aggregated together, and anthers finally crushed without dehiscence caused by inadequate endothecium lignification. Microarray analyses revealed that many genes encoding metabolic enzymes, including those involved in cell wall metabolism and lignin biosynthesis, were downregulated in the rpk2 mutants. RPK2 mRNA was abundant in the tapetum of wild-type anthers during microspore maturation. These results suggest that RPK2 controls tapetal cell fate to trigger its degradation and that mutating RPK2 inhibits pollen maturation and anther dehiscence due to disruption of key metabolic pathways.
