Production of toxic metabolites by two strains of Lasiodiplodia theobromae, isolated from a coconut tree and a human patient

Abstract

Lasiodiplodia theobromae is a phytopathogenic fungus that causes diseases not only in a broad number of plant hosts but also occasionally in humans. The capacity of L. theobromae to produce bioactive metabolites at 25 C (environmental mean temperature) and at 37 C (body mean temperature) was investigated. Two strains, CAA019 and CBS339.90, isolated respectively from a coconut tree and a human patient were characterized. The phytotoxicity and cytotoxicity (on mammalian cells) of the secretomes of both strains of L. theobromae were investigated. Also, phytotoxicity and cytotoxicity of pure compounds were evaluated. The phytotoxicity of the secretome of strain CAA019 was higher than the phytotoxicity of the secretome of strain CBS339.90 at 25 C. However, the phytotoxicity for both strains decreased when they were grown at 37 C. Only the secretome of strain CBS339.90 grown at 37 C induced up to 90% Vero and 3T3 cell mortality. This supports the presence of different metabolites in the secretome of strains CAA019 and CBS339.90. Metabolites typical of L. theobromae were isolated and identified from organic extracts of the secretome of both strains (e.g., 3-indolecarboxylic acid, jasmonic acid, lasiodiplodin, four substituted 2-dihydrofuranones, two melleins, and cyclo-(Trp-Ala)). Also, metabolites such as scytalone, not previously reported for this species, were isolated and identified. Metabolite production is affected by strain and temperature. In fact, some metabolites are strain specific (e.g., lasiodiplodin) and some metabolites are temperature specific (e.g., jasmonic acid). Although more strains should be characterized, it may be anticipated that temperature tuning of secondary-metabolite production emerges as a putative contributing factor in the modulation of L. theobromae pathogenicity towards plants, and also towards mammalian cells.

Secondary Metabolites Produced by Macrophomina phaseolina Isolated from Eucalyptus globulus

“…Melleins are also toxic metabolites produced by fungi and could be responsible for the toxic effects of culture filtrates and crude extracts of M. phaseolina PE35 [30,31,45].…”

“…Crude extracts were treated with N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) before GC-MS analysis because secondary metabolites may not have suitable gas chromatographic properties [28]. All metabolites were identified comparing their EI mass spectra at 70 eV with the ones present in the NIST 14 mass spectral library [29] and the custom GC-MS library described by Félix et al [30,31].…”

An In vitro Approach for Evaluating Antimicrobial Activity and Production of Kojic Acid by Aspergillus flavus Isolated from Karwar Region

“…As far as the advancement of the potentiality of fungi to produce a considerable number of biologically active secondary metabolites that are involved in enhancement of ecological strength, and most of them perform the significant role as agents in defense mechanism, advancing regulators, insect attractants and as an agent for communicating with other organisms 14 . These pharmacologically active substances exhibit various properties such as antimicrobial, antitumor, antihyper-cholesterolemic, and Immunosuppressant [15][16][17][18][19] .…”

Fatty Acids Produced by Neofusicoccum vitifusiforme and N. parvum, Fungi Associated with Grapevine Botryosphaeria Dieback

“…The most abundant component identified is linoleic acid (48.2%). Octadecenoid acids have influence in the fungal virulence because many of them are precursors of jasmonic acid [33], a plant hormone capable of inducing phytotoxic effects [12,22,[34][35][36][37]. Furthermore, Farmer and Ryan [38] tested the capacity of octadecenoid precursors of jasmonic acid, such as linolenic acid and linoleic acid (which can be converted to linolenic acid by the plant) to be inducers of proteinase inhibitors in tomato, tobacco, and alfalfa leaves.…”