Visual Estimation of Aflatoxin Production in Peanut with <i>Aspergillus</i> Norsolorinic Acid Mutants1

López, Yolanda; Keller, Nancy P.; Sarr, Bachir A.; Phillips, Timothy D.; Cuero, R. G.; Smith, O. D.

doi:10.3146/i0095-3679-25-2-7

Cited by 6 publications

(4 citation statements)

References 6 publications

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“…The mutant is blocked in AF biosynthesis after the formation of the first stable and committed intermediate, norsolorinic acid (NOR; [ 16 ]). nor mutants in A. flavus and A. parasiticus have been used as visual and quantitative reporters of AF both in growth media and infected seeds [ 17 , 18 ] and to analyze AF-biocontrol activities of yeasts [ 19 ]. The mutant allowed us to measure both fungistatic and anti-aflatoxigenic activities of all 29 RABs within the same experiment.…”

Section: Resultsmentioning

confidence: 99%

Rice Phyllosphere Bacillus Species and Their Secreted Metabolites Suppress Aspergillus flavus Growth and Aflatoxin Production In Vitro and in Maize Seeds

Subbaiah

DeRobertis

Pineda

et al. 2018

Toxins

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The emergence of super-toxigenic strains by recombination is a risk from an intensive use of intraspecific aflatoxin (AF) biocontrol agents (BCAs). Periodical alternation with interspecific-BCAs will be safer since they preclude recombination. We are developing an AF-biocontrol system using rice-associated Bacilli reported previously (RABs). More than 50% of RABs inhibited the growth of multiple A. flavus strains, with RAB4R being the most inhibitory and RAB1 among the least. The fungistatic activity of RAB4R is associated with the lysis of A. flavus hyphal tips. In field trails with the top five fungistatic RABs, RAB4R consistently inhibited AF contamination of maize by Tox4, a highly toxigenic A. flavus strain from Louisiana corn fields. RAB1 did not suppress A. flavus growth, but strongly inhibited AF production. Total and HPLC-fractionated lipopeptides (LPs) isolated from culture filtrates of RAB1 and RAB4R also inhibited AF accumulation. LPs were stable in vitro with little loss of activity even after autoclaving, indicating their potential field efficacy as a tank-mix application. A. flavus colonization and AF were suppressed in RAB1- or RAB4R-coated maize seeds. Since RAB4R provided both fungistatic and strong anti-mycotoxigenic activities in the laboratory and field, it can be a potent alternative to atoxigenic A. flavus strains. On the other hand, RAB1 may serve as an environmentally safe helper BCA with atoxigenic A. flavus strains, due its lack of strong fungistatic and hemolytic activities.

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Section: Resultsmentioning

confidence: 99%

Rice Phyllosphere Bacillus Species and Their Secreted Metabolites Suppress Aspergillus flavus Growth and Aflatoxin Production In Vitro and in Maize Seeds

Subbaiah

DeRobertis

Pineda

et al. 2018

Toxins

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“…The remaining aqueous phase was washed with 2.5 ml hexane. The hexane extracts were combined, allowed to dry and then resuspended in 500 µl of hexane before 10 µl of each extract was separated on a silica gel TLC plate using a hexane : ethyl acetate [40:10 (v/v)] solvent system (Lopez et al ., 1998).…”

Section: Methodsmentioning

confidence: 99%

Oxylipins act as determinants of natural product biosynthesis and seed colonization in Aspergillus nidulans

Tsitsigiannis

Keller

2005

Molecular Microbiology

140

132

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SummarySecreted, hormone-like lipogenic molecules, called oxylipins, mediate the balance of asexual to sexual spore ratio in Aspergillus nidulans . Oxylipin production in this fungus is dependent on developmental regulation of three conserved fatty acid oxygenases, PpoA, PpoB and PpoC. Here, we show that in addition to altering spore ratios, loss of ppo genes affect natural product biosynthesis and seed colonization. D ppoA; D ppoC and D ppoA; D ppoB; D ppoC mutants were unable to produce the mycotoxin sterigmatocystin (ST) in vitro or in planta but in contrast overproduced the antibiotic penicillin (PN). These findings were correlated with decreased expression of genes involved in ST biosynthesis and increased expression of a PN biosynthetic gene, thus suggesting that oxylipin species regulate secondary metabolites at the transcriptional level. Additionally, the D ppoA; D ppoC and the D ppoA; D ppoB; D ppoC mutants were defective in colonization of peanut seeds as reflected by a decrease in conidiation and production of the seed degradative enzyme lipase. These results indicate that oxylipin production is important for host colonization and mycotoxin production and may provide a promising target for future control strategies.

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“…Quatre nouvelles variétés créées par les programmes de sélection pour la résistance à la sécheresse conduits par l'Isra et le Cirad depuis 1984(Khalfaoui, 1991 ont été utilisées dans l'opération de développement. Dans un de ces programmes, le matériel végétal de base utilisé était constitué de lignées très précoces (cycle de 80 jours) issues de descendances de la variété 55-437, variété la plus cultivée au Sénégal et qui constitue le meilleur témoin de résistance à l'aflatoxine pour l'Afrique (Waliyar et al, 1994 ;López et al, 1998 ;Drame et al, 2007). Deux nouvelles variétés de 80 jours, issues de ce programme de réduction de la durée du cycle de 55-437, la variété GC8-35 (Fall et al, 2012a) et la variété 55-33 (Fall et al, 2012b), ont été utilisées dans l'opération de Paoskoto.…”

Section: Le Mécanisme De La Contamination De L'arachide Par Les Aflatoxines Et La Résistance Variétaleunclassified

Improving the health quality of groundnut in Senegal: A challenge for a participatory research and development action

Clavel¹,

Sylva²,

Ndoye³

et al. 2013

Cahiers Agricultures

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Amélioration de la qualité sanitaire de l'arachide au Sénégal : un challenge pour une opération de recherche-développement participative Résumé L'arachide est une culture au statut unique au Sénégal. Pratiquée par de petits agriculteurs familiaux, elle est à la fois culture de rente et vivrière, et donne lieu à de multiples formes de production et de transformation. Mais les sécheresses récurrentes et les contraintes économiques des producteurs ainsi que le manque de semences et d'infrastructures, notamment pour le séchage et le stockage des récoltes, constituent des freins à une production régulière et de qualité. Cet environnement est propice à l'infestation de l'arachide par l'Aspergillus flavus exposant massivement les populations locales à la contamination par l'aflatoxine des produits artisanaux de transformation de l'arachide. En outre, le durcissement des réglementations européennes sur les teneurs maximales en aflatoxines des arachides importées restreint fortement les possibilités d'exportation et accroît l'autoconsommation des graines susceptibles d'être contaminées. Nous relatons ici les résultats d'une opération participative conduite par l'organisation paysanne sénégalaise Asprodeb avec les petits producteurs et le concours de la recherche agricole afin de développer une production d'arachide saine et de qualité.

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Visual Estimation of Aflatoxin Production in Peanut with Aspergillus Norsolorinic Acid Mutants1

Cited by 6 publications

References 6 publications

Rice Phyllosphere Bacillus Species and Their Secreted Metabolites Suppress Aspergillus flavus Growth and Aflatoxin Production In Vitro and in Maize Seeds

Rice Phyllosphere Bacillus Species and Their Secreted Metabolites Suppress Aspergillus flavus Growth and Aflatoxin Production In Vitro and in Maize Seeds

Oxylipins act as determinants of natural product biosynthesis and seed colonization in Aspergillus nidulans

Improving the health quality of groundnut in Senegal: A challenge for a participatory research and development action

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