FIGURE 6.

Schematic illustration of a regulation network associated with pathogenesis and fitness in the tangerine pathotype of A. alternata. Low level of H₂O₂ generated by the NADPH oxidases (NOX) plays a central role in the activation of Yap1, Hog1, and Skn7, which subsequently regulate the expression of numerous genes associated with iron uptake and resistance to different stress including oxidants xenobiotics, fungicides, and osmolytes. Two MFS transporters regulated by Yap1 and/or Hog1 play an important role in the process. Transcriptional feedback inhibition of the Nox-coding genes by Yap1 and Hog1 was also observed. Detailed description can be found in the text.