GhGSTF12, a glutathione S-transferase gene, is essential for anthocyanin accumulation in cotton (Gossypium hirsutum L.)

Abstract

Anthocyanins are flavonoid pigments providing plants a range of colors from red, pink, orange to blue. Anthocyanins are synthesized in the cytosol but accumulate predominantly in the vacuoles through vacuolar sequestration involving glutathione S-transferases (GSTs) and multidrug and toxic compound extrusion (MATE) and the ATP binding cassette (ABC) transporters. However, little is known about anthocyanin-related GSTs in Upland cotton (Gossypium hirsutum L.). In this study, we performed genome-wide identification of GST genes in Upland cotton and identified GST genes functioning in accumulation of anthocyanins. We demonstrated that GhGSTF12 was able to complement the defective leaf color phenotypes of the Arabidopsis tt19 mutant caused by mutation in a GSTF gene. Virus-induced silencing of GhGSTF12 in the red leaf cultivar turned its red color to green and transient overexpression of GhGSTF12 accelerated anthocyanin accumulation in the red leaf cultivar but not in the green leaf cultivar. Collectively, GhGSTF12 may be involved in transport of anthocyanins from cytosol to vacuoles in cotton. These results also demonstrated a conserved function of plant GSTF genes in anthocyanin accumulation and provide a candidate gene for manipulating pigmentation in cotton tissues.

Keywords: Anthocyanin transporter; Cotton; GhGSTF12; Glutathione S-transferase.