Molecular cloning and characterization of an AP2/ERF protein gene in cotton (Gossypium hirsutum L.)

Upland cotton (Gossypium hirsutum L.) is one of the most economically important crops worldwide due to the significant source of natural fiber, feed, oil and biofuel products. Cottonseed can also serve as an excellent source of edible protein and oil. However,the presence of gossypol in pigment gland has limited it utilization In the past few decades, some progress has been made in the understanding molecular mechanism of the formation of the pigment gland. However, little is known about the specific mechanism of pigment gland formation in cotton. In this study, the cDNA sequence of a ethylene transcription factor gene, designated GhERF105a, was cloned from upland cotton CCRI12. Sequence alignment revealed that GhERF105a gene contained a typical AP2/ERF domain of 61 amino acids, and belonged to the ERF subgroup of the ERF supfamily. It was highly expressed in the leaves and stems of glanded plants but had substantially lower expression of the glandless plants. GhERF105a, localized to the nucleus, could bind to GCC-box and DRE. Some development, phytohormone and stress related cis-elements were enriched in the promoters of GhERF105a/d. Split ubiquitin assays in yeast and BiFC experiments showed extensive interactions between GhERF105a and Gh_A07G1044. In addition, GhERF105a was highly similar with GhERF105d in the gene length, molecular weight, protein molecule, gene structure and expression pattern. The overall results suggested that GhERF105a might participate in the pigment gland formation and stree-response processes.