Environmental stresses affect aflatoxin synthesis and conidiogenesis in a. flavus through sirtuin pathway involvement.

Aflatoxins are health hazardous secondary metabolites produced by the cosmopolitan fungus A. flavus. The ability of this fungus to exploit several substrates is also related to its psicrophylicity and enormous production of conidia. In relation to this, some ongoing climate changes favor plant susceptibility to the attack by this fungus with a consequent, dangerous, increase of aflatoxins into previously unexploited feed- and foodstuff. In this study we analyze how some environmental stresses to which A. flavus may undergo also during host exploitation – namely, hypoxia, pH alteration, carbon starvation and oxidative stress – affect aflatoxin biosynthesis, fungal growth and conidiogenesis. By multiple analytical approaches (mass spectrometry, transcriptional analysis, fluorimetric assays) we check the trend of specific molecular pathways related to metabolism reprogramming in consequence of environmental signals. Results indicate that sirtuins– a class of deacetylase enzymes – could represent the interface between signal transduction pathways and transcriptional reprogramming into A. flavus.Nevertheless the results obtained, further study to clearly define the role of sirtuins in shaping transcriptome in A. flavus are required.