Figure 1.

Impaired GA perception reduces barley root colonisation by P. indica. GA-responsive gene transcription is inhibited by SLENDER1 (SLN1) in the absence of GA (upper). After GA synthesis, GA gets attached to the GA receptor GID1. Thereafter, SLN1 binds to GID1, which results in SLN1 ubiqutination and its proteasomal degradation.²² By removing SLN1, GA-responsive transcription is initiated that is thought to modify plant defense signaling and metabolism (upper). In the barley mutant gid1, GA-responsive transcritption is inhibited and P. indica root colonisation is markedly reduced at 21 dai (lower right) compared to parent line Himalaya (lower left). Intracellular sporulation was almost absent in gid1 (inset, lower right). The fungus was stained with wheat germ agglutinin-Alexa Fluor 488 (WGA-AF 488) and visualized by fluorescence microscopy (Bars = 20 µm).