Structure and expression analysis of TaGW5 in common wheat

Abstract

OsGW5 (OsGSE) regulates cell proliferation and is involved in regulating grain size and thousand-grain weight in rice. Our knowledge about its wheat ortholog TaGW5 is limited. In the present study, we characterized the structure and expression of TaGW5 at molecular level in wheat and predicted the cis-elements and transcription factor binding sites (TFBS) of its promoter. The GW5 orthologs in barley (HvGW5), rice (OsGW5), Triticum turgidum L. (TtGW5) and Brachypodium distachyon (BdGW5) were also identified for comparative analyses. TaGW5 was mapped onto the short arms of group 1 chromosomes (1AS, 1BS, and 1DS). Multiple alignments indicated GW5 possesses three exons and two introns in all the analyzed species except for rice and the exon-intron junction composed of exon 2 and intron 2 was highly conserved. GW5 has a conserved domain (DUF 4005) and two neighboring IQ domains and was mainly expressed in wheat young spikes, in barley immature inflorescences and in rice anthers. Drought, heat and biotic-stress treatments had no significant effects on HvGW5 and TaGW5 expression. Significant correlation between the expression patterns of predicted transcription factor ABF2 and OsGW5 was also detected. Taken together, these results broaden our understanding of GW5 in wheat, barley and rice and will be helpful for further manipulating GW5 and uncovering its roles in plants