Tomato (Solanum lycopersicum) Homologs of TRIPTYCHON (SlTRY) and GLABRA3 (SlGL3) are involved in anthocyanin accumulation

In Arabidopsis thaliana the CPC-like MYB transcription factors CAPRICE (CPC), TRIPTYCHON (TRY), ENHANCER OF TRY AND CPC 1, 2, 3/CPC-LIKE MYB 3 (ETC1, ETC2, ETC3/CPL3), TRICHOMELESS 1, 2/CPC-LIKE MYB 4 (TCL1, TCL2/CPL4) and the bHLH transcription factors GLABRA3 (GL3) and ENHANCER OF GLABRA 3 (EGL3) are central regulators of trichome initiation and root-hair differentiation. By transforming the tomato orthologous genes SlTRY (TRY) and SlGL3 (GL3) into Arabidopsis, we demonstrated that SlTRY inhibited trichome initiation and enhanced root-hair differentiation. These results suggest that tomato and Arabidopsis partially use similar transcription factors for epidermal cell differentiation, and that a CPC-like R3 MYB may be a key common regulator of plant trichome and root-hair development. CPC and GL3 are also known to be involved in anthocyanin biosynthesis. Here, we show that anthocyanin accumulation was repressed in the CPC::SlTRY and GL3::SlGL3 transgenic plants, suggesting that SlTRY and SlGL3 can influence anthocyanin pigment synthesis.