Hair (H) interacts with SlZFP8-like to regulate the initiation and elongation of trichomes by modulating SlZFP6 expression in tomato

Trichomes are specialized glandular or non-glandular structures that provide physical or chemical protection against insect and pathogens attack. Trichomes in Arabidopsis, as typical non-glandular structures, have been extensively studied. However, the molecular mechanism underlying glandular trichome formation and elongation still remains largely unknown. We previously demonstrated that Hair (H) is essential for the formation of type I and type VI trichomes. Here, we found that overexpression of H increased the density and length of tomato trichomes. We revealed that H physically interacts with its close homolog SlZFP8-like (SlZFP8L) and SlZFP8L also directly interacts with Woolly (Wo) by biochemical assays. SlZFP8L overexpression plants showed increased trichome density and length. We further found that the expression of SlZFP6, encoding a C2H2 zinc finger protein, is positively regulated by H. We identified that SlZFP6, is a direct target of H through ChIP-qPCR, Y1H, and LUC assays. Similar to H and SlZFP8L, the overexpression of SlZFP6 also increased the density and length of tomato trichomes. Taken together, our results suggest that H interacts with SlZFP8-like to regulate the initiation and elongation of trichomes by modulating SlZFP6 expression in tomato.