title: Identification of the Anti-Aflatoxinogenic Activity of Micromeria graeca and Elucidation of Its Molecular Mechanism in Aspergillus flavus.
abstract: Of all the food-contaminating mycotoxins, aflatoxins, and most notably aflatoxin B₁ (AFB₁), are found to be the most toxic and economically costly. Green farming is striving to replace fungicides and develop natural preventive strategies to minimize crop contamination by these toxic fungal metabolites. In this study, we demonstrated that an aqueous extract of the medicinal plantMicromeria graeca-known as hyssop-completely inhibits aflatoxin production byAspergillus flavuswithout reducing fungal growth. The molecular inhibitory mechanism was explored by analyzing the expression of 61 genes, including 27 aflatoxin biosynthesis cluster genes and 34 secondary metabolism regulatory genes. This analysis revealed a three-fold down-regulation ofaflRandaflSencoding the two internal cluster co-activators, resulting in a drastic repression of all aflatoxin biosynthesis genes. Hyssop also targeted fifteen regulatory genes, includingveAandmtfA, two major global-regulating transcription factors. The effect of this extract is also linked to a transcriptomic variation of several genes required for the response to oxidative stress such asmsnA,srrA,catA,cat2,sod1,mnsod, andstuA. In conclusion, hyssop inhibits AFB₁ synthesis at the transcriptomic level. This aqueous extract is a promising natural-based solution to control AFB₁ contamination.
authors.affiliation: Toxalim, Université de Toulouse, INRA, ENVT, INP Purpan, UPS, Toulouse F-31027, France. rhodakhoury@gmail.com.|Laboratoire de Mycologie et Sécurité des Aliments (LMSA), Département des sciences de la vie et de la terres - Biochimie, Faculté des Sciences, Université Saint-Joseph, P.O. Box 17-5208, Mar Mikhael Beirut 1104 2020 Lebanon. rhodakhoury@gmail.com.
authors.forename: Rhoda
authors.initials: R
authors.lastname: El Khoury
authors.affiliation: Toxalim, Université de Toulouse, INRA, ENVT, INP Purpan, UPS, Toulouse F-31027, France. isauracaceres@hotmail.com.
authors.forename: Isaura
authors.initials: I
authors.lastname: Caceres
authors.affiliation: Toxalim, Université de Toulouse, INRA, ENVT, INP Purpan, UPS, Toulouse F-31027, France. olivier.puel@inra.fr.
authors.forename: Olivier
authors.initials: O
authors.lastname: Puel
authors.affiliation: Toxalim, Université de Toulouse, INRA, ENVT, INP Purpan, UPS, Toulouse F-31027, France. s.bailly@envt.fr.
authors.forename: Sylviane
authors.initials: S
authors.lastname: Bailly
authors.affiliation: Laboratory of Microbiology, Department of Natural Sciences and Earth, Faculty of Sciences I, Lebanese University, Hadath Campus, P.O. Box 5, Beirut, Lebanon. a.atoui@cnrs.edu.lb.
authors.forename: Ali
authors.initials: A
authors.lastname: Atoui
authors.affiliation: Toxalim, Université de Toulouse, INRA, ENVT, INP Purpan, UPS, Toulouse F-31027, France. isabelle.oswald@inra.fr.
authors.forename: Isabelle P
authors.initials: IP
authors.lastname: Oswald
authors.affiliation: Laboratoire de Mycologie et Sécurité des Aliments (LMSA), Département des sciences de la vie et de la terres - Biochimie, Faculté des Sciences, Université Saint-Joseph, P.O. Box 17-5208, Mar Mikhael Beirut 1104 2020 Lebanon. andre.khoury@usj.edu.lb.
authors.forename: André
authors.initials: A
authors.lastname: El Khoury
authors.affiliation: Toxalim, Université de Toulouse, INRA, ENVT, INP Purpan, UPS, Toulouse F-31027, France. jd.bailly@envt.fr.
authors.forename: Jean-Denis
authors.initials: JD
authors.lastname: Bailly
mesh_terms: D016604:Aflatoxin B1 / Q000096:biosynthesis*; D001231:Aspergillus flavus / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects; D005800:Genes, Fungal; D019686:Lamiaceae; D010936:Plant Extracts / Q000494:pharmacology*; D018515:Plant Leaves
chemical_list: D010936:Plant Extracts; D016604:Aflatoxin B1
keywords: Aflatoxin B1; Aspergillus flavus; hyssop; inhibition; oxidative stress