“…The Arabidopsis bHLH-type gene AtTT8 (TRANS-PARENT TESTA 8) is transcriptionally activated by AtTT2; it has a further synergic cooperative influence on the PAs structural genes and enhances their expression level ( Baudry et al, 2004;Koes et al, 2005; Baudry, Caboche, and Lepiniec, 2006; Shangguan, Yang, Zhang, and Wang, 2016). Similar observations were reported for GhTT2-3A and GhbHLH130D (AtTT8 ortholog) cotton genes -it was established that GhTT2-3A activates the GhbHLH130D gene (Table 2) (Gong et al, 2018). Dualluciferase assays demonstrated that the GhTT2-3A and GhbHLH130D genes affect the PAs biosynthesis structural genes, GhANR and GhLAR, and consequently induce PAs accumulation in cotton fibre (Yan et al, 2018).…”