Discovery of Tropolone Stipitaldehyde as a Potential Agent for Controlling Phytophthora Blight and Its Action Mechanism Research.

The fermentation of endophytic GGY-3 resulted in the isolation of tropolone stipitaldehyde (), which exhibited broad-spectrum inhibition activity against fungi and bacteria, especially against , with an EC value of 0.83 μg/mL and pv. , with a minimum inhibitory concentration value of 4.0 μg/mL. The in vitro and in vivo assays demonstrated that had a significant protective effect on . Furthermore, inhibited the spore germination of and damaged the plasma membrane structure. As observed by SEM and TEM, after exposure to , mycelia exhibited swelling, shrunken, branch-increasing phenomena, cell wall and membrane damage, and disordered content. Transcriptome analysis revealed that might affect starch and sucrose metabolism and fatty acid biosynthesis by suppressing the expression of genes relevant to cell wall synthetases and cell membrane-associated genes. These findings indicate that may be a potential agrochemical fungicide for controlling phytophthora blight.