Biotic stress caused by in vitro co-inoculation enhances the expression of acetylcholinesterase inhibitors by fungi.

Fungi are an inexhaustible source of bioactive metabolites that can be driven to find medicines for chronic diseases, as Alzheimer's disease. In the present work, five species of soil-originated fungi (Aspergillus chevalieri, Clonostachys rogersoniana, Fusarium nygamai, Penicillium sp., and Talaromyces calidicanius) were submitted to mutual biotic stress aiming at activating the expression of metabolites capable of inhibiting the enzyme acetylcholinesterase. HPLC profiles showed that the in vitro biotic stress triggered the biosynthesis of metabolite-mediated defense responses. Five compounds present in the complex co-culture matrix were identified by Paper Spray Mass Spectrometry (PS-MS). The approach enhanced the biosynthesis of acetylcholinesterase inhibitors (up to 99.6% inhibition) in comparison with the individual cultures. The mutual biotic stress between T. calidicanius and A. Chevalieri led to the biosynthesis of a pool of metabolites statistically as efficient as serine (p < 0.05), the positive control used in the experiments (99.6 and 99.1% inhibition, respectively).

Crop type exerts greater influence upon rhizosphere phosphohydrolase gene abundance and phylogenetic diversity than phosphorus fertilization.

Rock phosphate is an alternative form of phosphorus (P) fertilizer; however, there is no information regarding the influence of P fertilizer sources in Brazilian Cerrado soils upon microbial genes coding for phosphohydrolase enzymes in crop rhizospheres. Here, we analyze a field experiment comparing maize and sorghum grown under different P fertilization (rock phosphate and triple superphosphate) upon crop performance, phosphatase activity and rhizosphere microbiomes at three levels of diversity: small subunit rRNA marker genes of bacteria, archaea and fungi; a suite of alkaline and acid phosphatase and phytase genes; and ecotypes of individual genes. We found no significant difference in crop performance between the fertilizer sources, but the accumulation of fertilizer P into pools of organic soil P differed. Phosphatase activity was the only biological parameter influenced by P fertilization. Differences in rhizosphere microbiomes were observed at all levels of biodiversity due to crop type, but not fertilization. Inspection of phosphohydrolase gene ecotypes responsible for differences between the crops suggests a role for lateral genetic transfer in establishing ecotype distributions. Moreover, they were not reflected in microbial community composition, suggesting that they confer competitive advantage to individual cells rather than species in the sorghum rhizosphere.