KINKY POLLEN and POKY POLLEN TUBE are two novel genes required for tip growth and duplicated in the Arabidopsis genome

Screening of male gametophytic mutants from the Versailles collection of T-DNA transformants. allowed us to isolate and characterize two novel genes: KINKY POLLEN (KIP) and POKY POLLEN TUBE (POK), which are required for correct tip growth in Arabidopsis thaliana. As KIP and POK are expressed in all plant tissues, though to a higher level in pollen and roots, their roles may not be restricted to tip growth only, but might extend to more general elongation mechanisms. Both genes are duplicated in the Arabidopsis genome. Specific roles for each duplicate, indicated by mutant phenotypes, will be discussed. Moreover, KIP and POK proteins have putative orthologs in all eukaryotes investigated, suggesting that they may be crucial proteins required for correct polar growth in all eukaryotic species.