Figure 12.

Model of the Involvement of UGT76B1 as a Novel Mediator in SA- and JA-Dependent Regulation of Defense Responses and Senescence.

The model relates UGT76B1 to SA and JA pathways regulating defense against (hemi-) biotrophic and necrotrophic pathogens. Key steps of both pathways are shown. UGT76B1 induces the JA response and represses the SA-dependent pathway, stimulating defense against necrotrophs and having a negative influence on the resistance to P. syringae and the onset of senescence. The UGT76B1 substrate ILA enhances the SA pathway. The consequences of gain and loss of UGT76B1 function are integrated along with their dependence on SID2 and JAR1. Signaling molecules (SA, SAG, JA, JA-Ile), enzymatic transformations (dashed and open arrows), activation (closed arrows), suppression (line with vertical bar), and important genes are indicated. Positive and negative influences of ugt76b1 (gray) and UGT76B1-OE (black) are shown, respectively.