The Arabidopsis TCP16 gene encoding a putative transcription factor is essential for pollen development as a gametophytically acting factor

Abstract

Pollen development is a fundamental and essential biological process in flowering plants. Although several sporophytic and gametophytic mutations affecting male gametogenesis have been isolated and analyzed, little is known about the precise molecular mechanism. We identified two mutational alleles of the TCP16 gene. Genetic analysis revealed that the mutational alleles are hardly transmitted to the progeny specifically through male gametophytes. The mature pollen grains generated in the heterozygous tcp16 mutant comprised equal amounts of normal and abnormal, non-viable, pollen grains. Expression analysis of the promoter::GUS fusion gene suggested that the TCP16 transcription is activated at early stage from the tetrad to the unicellular stage, at which the defective phenotype is observed. Because the TCP16 gene encodes a putative transcription factor carrying a TCP domain, our results strongly suggested that TCP16 plays an essential and crucial role in early processes in pollen development as a transcriptional regulator.