Comparative transcript profiling of TCP family genes provide insight into gene functions and diversification in rice and Arabidopsis

Abstract

Plant-specific TCP transcription factor family has been implicated in diverse aspects of growth and development. Rice and Arabidopsis genomes encode 26 and 24 TCP family genes, respectively. In this study, we have performed an inclusive analysis of their expression during 21 and 18 stages of development in rice and Arabidopsis, respectively. The assorted patterns of expression, exhibited by TCP family genes, provide an evidence for spatiotemporal regulation of their relative abundance throughout plant development. Further profiling of rice genes in three sub-stages of early panicle development revealed differential accumulation of nine genes during panicle initiation and organ development. QPCR-based expression profiling of selected rice genes, during four stages of anther, suggested their involvement in early anther development as well. Eleven genes of rice and seven of Arabidopsis were differentially expressed in response to three abiotic stress treatments viz., cold, dehydration and salt. In silico analysis of 5' regulatory regions of differentially expressed genes revealed the presence of previously characterized cis-regulatory elements. Duplications seem to have played major role in diversification of TCP family genes with 14 genes of rice and 10 of Arabidopsis lying on duplicated segments of the respective genomes. Most of the duplicated genes exhibited varied expression patterns. The knowledge obtained in this study will be useful for selection and assessment of the functions of individual genes using reverse genetics approaches.