Dataset Information

Biodegradation of ochratoxin A by endophytic Trichoderma koningii strains.

ABSTRACT: Ochratoxin A (OTA) is a mycotoxin produced by Aspergillus spp. and Penicillium spp. that causes a threat to food safety and human health. Fungal biodegradation might be a promising strategy for reducing the OTA contamination in the future. In this study, the ability of Trichoderma koningii strains to degrade OTA produced by Aspergillus niger T2 (MW513392.1) isolated from tomato seeds was investigated. Among T. koningii strains tested, three strains; AUMC11519, AUMC11520 and AUMC11521 completely eliminated OTA from the culture medium, while AUMC11522 strain eliminated only 41.82% of OTA. OTα-amide, 3-phenylpropionic acid, OTα and phenylalanine were assayed as degradation products by FTIR analysis and LC-MS/MS spectra. Carboxypeptidase A (CPA) was found responsible for OTA degradation when a metal ion chelator, EDTA, was added to cell free supernatants of the three effective strains. OTA detoxification by T. koningii could present new prospective strategies for a possible application in food commodities intoxicated with ochratoxin.

SUBMITTER: Ismaiel AA

PROVIDER: S-EPMC9789014 | biostudies-literature | 2022 Dec

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Biodegradation of ochratoxin A by endophytic Trichoderma koningii strains.

Ismaiel Ahmed A AA Mohamed Hala H HH El-Sayed Manal T MT

World journal of microbiology & biotechnology 20221224 2

Ochratoxin A (OTA) is a mycotoxin produced by Aspergillus spp. and Penicillium spp. that causes a threat to food safety and human health. Fungal biodegradation might be a promising strategy for reducing the OTA contamination in the future. In this study, the ability of Trichoderma koningii strains to degrade OTA produced by Aspergillus niger T2 (MW513392.1) isolated from tomato seeds was investigated. Among T. koningii strains tested, three strains; AUMC11519, AUMC11520 and AUMC11521 completely ...[more]

PMID: 36564607

Similar Datasets

Project description:Rapeseed (Brassica napus L.) is the world's third most important edible oilseed crop after soybean and palm. The clubroot disease caused by Plasmodiophora brassicae poses a significant risk and causes substantial yield losses in rapeseed. In this study, 13 endophytic fungal strains were isolated from the healthy roots of rapeseed (B. napus) grown in a clubroot-infested field and molecularly identified. Based on germination inhibition of resting spores of P. brassicae, two endophytic fungal antagonists, Trichoderma spp. ReTk1 and ReTv2 were selected to evaluate their potential for plant growth promotion and biocontrol of P. brassicae. The Trichoderma isolates were applied as a soil drench (1×107 spore/g soil) to a planting mix and field soil, in which plants were grown under non-infested and P. brassicae-infested (2×106 spore/g soil) conditions. The endophytic fungi were able to promote plant growth, significantly increasing shoot and root length, leaf diameter, and biomass production (shoots and root weight) both in the absence or presence of P. brassicae. The single and dual treatments with the endophytes were equally effective in significantly decreasing the root-hair infection, root index, and clubroot severity index. Both ReTk1 and ReTv2 inhibited the germination of resting spores of P. brassicae in root exudates. Moreover, the endophytic fungi colonized the roots of rapeseed extensively and possibly induced host resistance by up-regulated expression of defense-related genes involved in jasmonate (BnOPR2), ethylene (BnACO and BnSAM3), phenylpropanoid (BnOPCL and BnCCR), auxin (BnAAO1) and salicylic acid (BnPR2) pathways. Based on these findings, it is evident that the rapeseed root endophytes Trichoderma spp. ReTk1 and ReTv2 could suppress the gall formation on rapeseed roots via antibiosis, induced systemic resistance (ISR), and/or systemic acquired resistance (SAR). According to our knowledge, this is the first report of the endophytic Trichoderma spp. isolated from root tissues of healthy rapeseed plants (B. napus.), promoting plant growth and reducing clubroot severity.

Project description:A GH (glycoside hydrolase) family 54 alpha-L-arabinofuranosidase from Trichoderma koningii G-39 (termed Abf) was successfully expressed in Pichia pastoris and purified to near homogeneity by cation-exchange chromatography. To determine the amino acid residues essential for the catalytic activity of Abf, extensive mutagenesis of 24 conserved glutamate and aspartate residues was performed. Among the mutants, D221N, E223Q and D299N were found to decrease catalytic activity significantly. The kcat values of the D221N and D299N mutants were 7000- and 1300-fold lower respectively, than that of the wild-type Abf. E223Q was nearly inactive. These results are consistent with observations obtained from the Aspergillus kawachii alpha-L-arabinofuranosidase three-dimensional structure. This structure indicates that Asp221 of T. koningii Abf is significant for substrate binding and that Glu223 as well as Asp299 function as a nucleophile and a general acid/base catalyst for the enzymatic reaction respectively. The catalytic mechanism of wild-type Abf was further investigated by NMR spectroscopy and kinetic analysis. The results showed that Abf is a retaining enzyme. It catalyses the hydrolysis of various substrates via the formation of a common intermediate that is probably an arabinosyl-enzyme intermediate. A two-step, double-displacement mechanism involving first the formation, and then the breakdown, of an arabinosyl-enzyme intermediate was proposed. Based on the kcat values of a series of aryl-alpha-L-arabinofuranosides catalytically hydrolysed by wild-type Abf, a relatively small Brønsted constant, beta(lg)=-0.18, was obtained, suggesting that the rate-limiting step of the enzymatic reaction is the dearabinosylation step. Further kinetic studies with the D299G mutant revealed that the catalytic activity of this mutant depended largely on the pK(a) values (>6) of leaving phenols, with beta(lg)=-1.3, indicating that the rate-limiting step of the reaction becomes the arabinosylation step. This kinetic outcome supports the idea that Asp299 is the general acid/base residue. The pH activity profile of D299N provided further evidence strengthening this suggestion.

Dataset Information

Biodegradation of ochratoxin A by endophytic Trichoderma koningii strains.

Publications

Biodegradation of ochratoxin A by endophytic Trichoderma koningii strains.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets