Method for biotransformation of trichothecenes
The present invention relates to a novel method for detoxification of trichothecene contaminated material. More specifically the present invention pertains to a method for biotransformation of a trichothecene by contacting material contaminated with trichothecenes with an exogenous non-animal glutathione-S-transferase (GST) having substrate specificity for the epoxide ring of the trichothecene. The invention further relates to recombinant GSTs and transgenic plants and animals expressing said GSTs.
1 . A method for biotransformation of a trichothecene by contacting material contaminated with trichothecenes with an exogenous non-animal glutathione-S-transferase (GST) having substrate specificity for the epoxide ring of the trichothecene, comprising
incubating components comprising the material, the GST, and glutathione in an aqueous solution at a pH range of 6 to 9 under conditions wherein glutathione reacts with the epoxide moiety, thereby forming an epoxide adduct, wherein:
(i) the GST has at least 95% sequence identity with SEQ ID NO: 2 or SEQ ID NO: 4, or the GST has an amino acid sequence as defined in (i) and is encoded by a polynucleotide sequence having at least 95% sequence identity with SEQ ID NO: 1 or SEQ ID NO: 3.
2 . The method according to claim 1 , wherein the trichothecene is selected from the group consisting of type A trichothecenes, type B trichothecenes, type C trichothecenes, and type D trichothecenes, optionally the trichothecene is selected from the group consisting of T-2 toxin, HT-2 toxin, neosolaniol, deoxynivalenol (DON), nivalenol (NIV), trichothecin, 3- and 15-acetyldeoxynivalenol, roridin A and verrucarin A.
3 . The method according to claim 1 , which comprises decontaminating liquid or solid material or material surface, textile material, filter material, gas masks, or air conditioning systems, or purifying material surfaces, or animal or human surfaces.
4 . The method according to claim 1 , wherein the GST is the recombinant GST, having the amino acid sequence of SEQ ID NO: 4, or having at least 95%, or at least 99% sequence identity with SEQ ID NO: 4 and having substrate specificity for the epoxide ring of the trichothecene.
5 . The method according to claim 1 , wherein the GST is encoded by the polynucleotide sequence selected from the group consisting of SEQ ID NO: 1, and SEQ ID NO: 3.
6 . The method according to claim 1 , wherein the GST is expressed in a host cell.
7 . A feed additive or feed material comprising a recombinant exogenous non-animal GST which has substrate specificity for the epoxide ring of a trichothecene, wherein said feed additive or feed material is produced by the method according to claim 1 .
8 . The feed additive or feed material according to claim 7 , comprising a transgenic plant part, transgenic plant tissue, transgenic plant cell, seed or progeny thereof, leaf, stem, root, cotyledon, or hypocotyl, each of the foregoing containing an exogenous GST having substrate specificity for the epoxide ring of the trichothecene.
9 . The method according to claim 1 , wherein: (i) the GST has at least 99% sequence identity with SEQ ID NO: 2 or SEQ ID NO: 4, or the GST has an amino acid sequence as defined in (i) and is encoded by a polynucleotide sequence having at least 99% sequence identity with SEQ ID NO: 1 or SEQ ID NO: 3.
10 . The method according to claim 2 , wherein the trichothecene is a type B trichothecene.
11 . The method according to claim 10 , wherein the type B trichothecene comprises deoxynivalenol (DON), nivalenol (NIV), trichothecin, 3-acetyldeoxynivalenol, or 15-acetyldeoxynivalenol.