Differential modulation of α-pyrone production in co-cultures of Pestalotiopsis diospyri with three phytopathogenic fungi
摘要
This study investigates the interactions between Pestalotiopsis diospyri and three phytopathogenic fungi—Fusarium guttiforme, Colletotrichum horii, and C. gloeosporioides—isolated from papaya and pineapple. A comparative analysis of metabolite production using 1H NMR was conducted under axenic and co-culture conditions with rice and potato dextrose broth (PDB) media. Principal Component Analysis (PCA) and Orthogonal Partial Least Squares Discriminant Analysis (OPLS-DA) of the 1H NMR data revealed metabolic trends between axenic and co-culture conditions, while compound-specific PCA demonstrated distinct species-based metabolite clustering, supporting the observed metabolic changes during interspecies interactions. The results revealed various classes of metabolites in the axenic cultures; however, in the tri-cultures, α-pyrones synthesized exclusively by P. diospyri were differentially expressed, with compounds 11 and 12 showing up to 2-fold increases in yield. The diverse survival strategies exhibited by these fungi, including antagonistic and parasitic behaviors, notably influenced their interactions, leading to the up-regulation and down-regulation of specific metabolites, particularly α-pyrones. Comparative ¹H NMR profiling indicated that the metabolic response to co-culture was dominated by known α-pyrones, with no detectable emergence of uncharacterized metabolites that might signal the production of potent toxins. Furthermore, our findings indicate that the rice medium enhances substrate-fungi interactions, thereby increasing both chemo-diversity and metabolite yield. Preliminary antifungal assays revealed that the α-pyrones exhibited weak to moderate, strain-specific activity against the phytopathogenic fungi, suggesting their ecological role in interspecies competition rather than as potent antimicrobial agents.