Genome-wide identification and characterization of <i>Gretchen Hagen3</i> (<i>GH3</i>) family genes in <i>Brassica napus</i>

Abstract

The hormone auxin is involved in many biological processes throughout a plant’s lifecycle. However, genes in the GH3 (Gretchen Hagen3) family, one of the three major auxin-responsive gene families, have not yet been identified in oilseed rape (Brassica napus). In this study, we identified 63 BnaGH3 genes in oilseed rape using homology searches. We analyzed the chromosome locations, gene structures, and phylogenetic relationships of the BnaGH3 genes, as well as the cis-elements in their promoters. Most BnaGH3 genes are located on chromosomes A03, A09, C02, C03, and C09, each with 4–7 members. In addition, we analyzed the expression patterns of BnaGH3 genes in seven tissues by transcriptome sequencing and quantitative RT-PCR analysis of plants under exogenous IAA treatment. The BnaGH3 genes showed different expression patterns in various tissues. BnaA.GH3.2-1 and BnaC.GH3.2-1 were expressed in the seed and seed coat during development and in response to IAA treatment. These results shed light on the possible roles of the GH3 gene family in oilseed rape.