Wheat GT-1-like Transcription Factor Boosts Cutin Biosynthesis

Cutin matrices in the cuticle cover plant epidermis, facilitating plant adaptation to stressful environments. Although cutin biosynthesis is extensively explored in the model plant Arabidopsis thaliana, the molecular mechanism governing cutin biosynthesis in the agriculturally important crop bread wheat (Triticum aestivum L.) remains largely unknown. The aim of the study is the characterization of the function and transcriptional regulation of a wheat gene involved in cutin biosynthesis. Long-chain acyl-CoA synthetase TaLACS2 was identified as an essential component of the wheat cutin biosynthetic machinery. Silencing of the wheat TaLACS2 gene by barley stripe mosaic virus-induced gene silencing assay resulted in remarkably reduced cutin accumulation and increased cuticle permeability. Furthermore, wheat GT-1-like transcription factor TaGT-3b was identified as a positive regulator of cutin biosynthesis. Silencing of the wheat TaGT-3b gene led to significantly decreased cutin accumulation and enhanced cuticle permeability. Importantly, we found that TaGT-3b could occupy the promoter regions of the TaLACS2 gene and that it functions as a transcriptional activator to activate TaLACS2 gene transcription. Collectively, these results elucidated that wheat GT-1-like transcription factor TaGT-3b boosts cutin biosynthesis, probably by activating TaLACS2 gene transcription, contributing to genetically improving cutin-associated traits in bread wheat.