Morphogenetic Metabolic and Molecular Dynamics during Mycelial Interactions among Fungal species

Abstract

In nature, microorganisms interact/compete with one other for food and newlinespace and the type of interactions are unique to each interacting species. Fungal-fungal newlineinteractions are complex, and different types of secondary metabolites are secreted newlineduring interaction. In this study, 14 fungal isolates were facilitated in 105 possible newlinecombinations to interact in potato dextrose agar (PDA). Ten interactions between newlinedifferent fungal isolates showed mutual replacement with each fungus; capturing newlineterritory from the other. Thirty-five interactions showed complete replacement as newlinegrowth of one of the fungal partners was inhibited. In forty-six interactions, formation newlineof barrage was observed leading to deadlock type of interaction wherein both fungi have newlinerestricted growth. newlineThe barrage formation during interaction was further studied with two newlinefungal interactions viz., (i) T. coccinea vs. L. lactinea and (ii) T. coccinea vs. newlineT. versicolor. Microscopic changes were observed in the hyphal growth during newlineinteraction like hyphal coiling, dense mycelial network, pore formation. Fungal-fungal newlineinteraction often leads to the change in metabolite profile of both the interacting fungus newlinewhich may have potential implication in industry or agriculture. The metabolites newlineproduced during interaction of Trametes coccinea (F3) with Leiotrametes lactinea (F9) newlineand Trametes coccinea (F3) with Trametes versicolor (F1) was analysed through Liquid newlineChromatography coupled with Mass Spectroscopy (LC-MS). Most of the metabolites newlinesecreted during interaction are associated with defensive response. The bipartite fungal newlineinteraction resulted in the production of a dark brown colour pigment melanin as newlineconfirmed by the LC-MS, FTIR and NMR analysis. Moreover, the fungal-fungal newlineinteraction also led to increase in the production of laccase, a group of multicopper newlineoxidases involved in detoxification of toxic compounds. Further increased activity of newlinesuperoxide dismutase, an enzyme that catalyzes the dismutation of the superoxide anion newlineto hydrogen peroxide was also recorded during fungal fungal interaction. There was newlinesignificant increase in the activities of hydrolytic enzymes including cellulase, xylanase newlineand chitinase during in vitro fungal-fungal interaction, suggesting the importance of newlinesuch interactions for commercial enzyme production. Quantitative real-time PCR newlinerevealed upregulation of lcc1 (encoding a laccase enzyme) and few other stress related newlinegenes of T. versicolor during its hyphal interaction with T. coccinea, suggesting a direct newlinecorrelation between laccase production and melanin production. The study helped to newlinegain a better understanding on the morpho-physiological, biochemical and gene newlineexpression profiles during in vitro fungal-fungal interaction. Such interactions induce newlinethe production and secretion of an array of metabolites and enzymes which can be newlineprospected towards biotechnological applications.