Wheat Transcription Factor TaMYB60 Modulates Cuticular Wax Biosynthesis by Activating TaFATB and TaCER1 Expression

Cuticular wax mixtures cover the epidermis of land plants and shield plant tissues from abiotic and biotic stresses. Although cuticular wax-associated traits are employed to improve the production of bread wheat, regulatory mechanisms underlying wheat cuticular wax biosynthesis remain poorly understood. In this research, partially redundant transcription factors TaMYB60-1 and TaMYB60-2 were identified as positive regulators of wheat cuticular wax biosynthesis. Knock-down of wheat <i>TaMYB60-1</i> and <i>TaMYB60-2</i> genes by virus-induced gene silencing resulted in attenuated wax accumulation and enhanced cuticle permeability. The roles of wheat fatty acyl-ACP thioesterase genes <i>TaFATB1</i> and <i>TaFATB2</i> in cuticular wax biosynthesis were characterized. Silencing wheat <i>TaFATB1</i> and <i>TaFATB2</i> genes led to reduced wax accumulation and increased cuticle permeability, suggesting that <i>TaFATB1</i> and <i>TaFATB2</i> genes positively contribute to wheat cuticular wax biosynthesis. Importantly, transcription factors TaMYB60-1 and TaMYB60-2 exhibit transcriptional activation ability and could stimulate the expression of wax biosynthesis genes <i>TaFATB1</i>, <i>TaFATB2</i>, and <i>ECERIFERUM 1</i> (<i>TaCER1</i>). These findings support that transcription factor TaMYB60 positively regulates wheat cuticular wax biosynthesis probably by activating transcription of <i>TaFATB1</i>, <i>TaFATB2</i>, and <i>TaCER1</i> genes.