Figure 5: A proposed model of gossypol biosynthesis and gland formation.
From: Genetic basis for glandular trichome formation in cotton
(a) Among 111 bHLH members (Supplementary Data 2), 19 bHLHs from the distinct clade II may be responsible for glandular trichome formation. Numbers on branch nodes indicate percentage support in 1,000 bootstrap trials. (b) A proposed model of gossypol biosynthesis and gland formation. Blue text indicates genes downregulated in GoPGF-silenced TM-1. Heat map shows gene expression level with FPKM value in VIGS-free TM-1 (AT), PGF-silenced TM-1 (P) and Hai-1 (H), each block indicates one gene. First, the expression of GoPGF is induced by exogenous signal including JA. Then, GoPGF protein, as a regulator, controls the specification and differentiation of gland cells through regulating the expression of JAZ, WRKYs or other genes. On the other hand, GoPGF can specifically interact with the G-box motif, which is commonly found in TPSs and WRKYs promoter regions to feedback on gossypol biosynthesis pathway.
