Unraveling the Alteration of Chemical Compositions in Cordyceps and Its Host Larvae Using Mass Spectrometry Imaging

Abstract

Cordyceps (Chinese Caterpillar Fungus) is a precious medicinal and edible fungus-larvae complex that is naturally formed in a specific environment. However, limited data have been reported on spatial alterations in the lipidome and metabolome of larvae before and after entomopathogenic fungal infection. In this work, changes in chemical composition and spatial chemical distribution patterns between host larvae and the fungus-larvae complex were visualized and characterized using matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI). Liquid chromatography-mass spectrometry (LC-MS) was performed to support MALDI MSI results. Our work revealed the single dominant distribution of many compounds in the host larva, as well as the stroma and sclerotium of Cordyceps. Based on further analysis, the heterogeneous distribution of certain lipid classes across the host larva, stroma and sclerotium of Cordyceps was revealed, reflecting key lipid metabolic events, such as assimilation, dissimilation, and synthesis of derivatives. Small metabolites were also detected, and an increase in both the amount and the kinds was observed from larvae to Cordyceps.