Trichoderma viride Laccase Plays a Crucial Role in Defense Mechanism against Antagonistic Organisms

Abstract

Fungal laccases are involved in a variety of physiological functions such as delignification, morphogenesis, and parasitism. In addition to these functions, we suggest that fungal laccases are involved in defense mechanisms. When the laccase secreting Trichoderma viride was grown in the presence of a range of microorganisms including bacteria and fungi, laccase secretion was enhanced in response to antagonistic organisms alone. In addition, growth of antagonistic microbes was restricted by the secreting fungi. Besides, our study for the first time shows the inability of the secreting fungi (T. viride) to compete with antagonistic organism when laccase activity is inhibited, further emphasizing its involvement in rendering a survival advantage to the secreting organism. When laccase inhibitor was added to the media, the zone of inhibition exerted by the antagonist organism was more pronounced and consequently growth of T. viride was significantly restricted. Based on these observations we accentuate that, laccase plays an important role in defense mechanism and provides endurance to the organism when encountered with an antagonistic organism in its surrounding.

Laccase Properties, Physiological Functions, and Evolution

“…and A. ochraceus cells. Lakshmanan and Sadasivan [172] reported recently that inhibition of T. viride laccase causes the inability of this fungus to compete with antagonistic microorganisms.…”

How Do Leaf-Cutting Ants Recognize Antagonistic Microbes in Their Fungal Crops?

“…This inhibition could involve compounds with antimicrobial properties, as observed for the cultivar of Cyphomyrmex ants, which produces lepiochlorin (Hervey and Nair, 1979) and diketopiperazines (Wang et al, 1999). An additional defensive barrier could be constituted by cultivarsecreted laccases (De Fine Licht et al, 2013), detoxifying secondary metabolites produced by antimicrobial-producing antagonists (Divya and Sadasivan, 2016).…”

Enhanced lactic acid production by Bacillus coagulans through simultaneous saccharification, biodetoxification, and fermentation

“…Trichoderma viride was also reported to degrade polycyclic aromatic hydrocarbons (PAHs) including bisphenol A in soil remediation and pyrene benzo[a]pyrene in water remediation . Laccase from T. viride was able to oxidize directly a variety of phenolic compounds used in PAHs and antagonistic microbial interactions . Enzymes from T. viride are therefore predicted to degrade the phenolic compounds generated in lignocellulose pretreatment, which significantly inhibit microbial fermentation in low concentrations …”