Perylenequinones (PQ) that notably produce reactive oxygen species upon exposure to visible light are a class of photoactivated polyketide mycotoxins produced by fungal plant pathogens such as Shiraia sp. The involvement of Ca/calmodulin (CaM) signalling in PQ biosynthesis was investigated by submerged culturing of Shiraia sp. Slf14, a species that produces hypocrellins HA and HB and elsinochromes EA, EB, and EC. Our results showed that the total content of PQ reached 1894.66 ± 21.93 mg/L under optimal conditions of Ca addition, which represents a 5.8-fold improvement over controls. The addition of pharmacological Ca sensor inhibitors strongly inhibited PQ production, which indicates that Ca/CaM signalling regulates PQ biosynthesis. The expression levels of Ca sensor and PQ biosynthetic genes were downregulated following addition of inhibitors but were upregulated upon addition of Ca. Inhibition was partially released by external Ca supplementation. Fluo-3/AM experiments revealed that similar cytosolic Ca variation occurred under these conditions. These results demonstrated that Ca signalling via the CaM transduction pathway plays a pivotal role in PQ biosynthesis.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.