The Arabidopsis DRYK, AtYAK1 regulates the development of the male gametophyte

Pollen is the male gametophyte of land plants. Proper development and maturation of pollen is necessary for the successful reproduction of seed plants. This process involves sophisticated coordination between sporophytic and gametophytic tissues in anthers. To advance the mechanistic studies of anther development, additional players need to be discovered for a comprehensive understanding of the underlying regulatory network. Here we show that the Arabidopsis dual specificity tyrosine phophorylated and regulated kinase (DRYK), AtYAK1, is essential for development of rosette leaves and the male but not female gametophyte in Arabidopsis. Arabidopsis mutant plants carrying a mutation in AtYAK1 produce developmentally stalled microspores, likely because of the defects in the two consecutive mitosis steps in the post-meiotic maturation process of pollen. The mutation of AtYAK1 has a significant effect on gene expression programs in developing pollen. Transcritpome analysis of atyak1 revealed downstream genes in families of protein kinases, transporters and transcription factors, which potentially contribute to pollen development. This study represents the first molecular characterization of DYRK in the plant kingdom. Our results also imply that the regulation of cytokinesis by DYRKs is evolutionally conserved in fungus, fruit fly, animals and plants.

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