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Resilience of Biocontrol for Aflatoxin Minimization Strategies: Climate Change Abiotic Factors May Affect Control in Non-GM and GM-Maize Cultivars

There has been significant interest in the development of formulations of non-toxigenic strains of Aspergillus flavus for control of toxigenic strains to reduce the aflatoxin B(1) (AFB(1)) contamination of maize. In the future, climate change (CC) abiotic conditions of temperature (+2–4°C), CO(2) (e...

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Autores principales: Gasperini, Alessandra Marcon, Rodriguez-Sixtos, Alicia, Verheecke-Vaessen, Carol, Garcia-Cela, Esther, Medina, Angel, Magan, Naresh
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6856084/
https://www.ncbi.nlm.nih.gov/pubmed/31787944
http://dx.doi.org/10.3389/fmicb.2019.02525
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author Gasperini, Alessandra Marcon
Rodriguez-Sixtos, Alicia
Verheecke-Vaessen, Carol
Garcia-Cela, Esther
Medina, Angel
Magan, Naresh
author_facet Gasperini, Alessandra Marcon
Rodriguez-Sixtos, Alicia
Verheecke-Vaessen, Carol
Garcia-Cela, Esther
Medina, Angel
Magan, Naresh
author_sort Gasperini, Alessandra Marcon
collection PubMed
description There has been significant interest in the development of formulations of non-toxigenic strains of Aspergillus flavus for control of toxigenic strains to reduce the aflatoxin B(1) (AFB(1)) contamination of maize. In the future, climate change (CC) abiotic conditions of temperature (+2–4°C), CO(2) (existing levels of 400 vs. 800–1,200 ppb), and drought stress will impact on the agronomy and control of pests and diseases. This study has examined (1) the effect of two-way interacting factors of water activity × temperature on colonization and AFB(1) contamination of maize cobs of different ripening ages; (2) the effect of non-toxigenic strains of A. flavus (50:50 inoculum ratio) on relative control of toxigenic A. flavus and AFB(1) contamination of ripening cobs; (3) post-harvest control of AFB(1) by non-toxigenic strains of A. flavus in non-GM and isogenic GM maize cultivars using the same inoculum ratio; and (4) the impact of three-way interacting CC factors on relative control of AFB(1) in maize cobs pre-harvest and in stored non-GM/GM cultivars. Pre-harvest colonization and AFB(1) production by a toxigenic A. flavus strain was conserved at 37°C when compared with 30°C, at the three ripening stages of cob development examined: milk ripe (R3), dough (R4), and dent (R5). However, pre-harvest biocontrol with a non-toxigenic strain was only effective at the R3 and R4 stages and not at the R5 stage. This was supported by relative expression of the aflR regulatory biosynthetic gene in the different treatments. When exposed to three-way interacting CC factors for control of AFB(1) pre-harvest, the non-toxigenic A. flavus strain was effective at R3 and £4 stages but not at the R5 stage. Post-harvest storage of non-GM and GM cultivars showed that control was achievable at 30°C, with slightly better control in GM-cultivars in terms of the overall inhibition of AFB(1) production. However, in stored maize, the non-toxigenic strains of A. flavus had conserved biocontrol of AFB(1) contamination, especially in the GM-maize cultivars under three-way interacting CC conditions (37°C × 1,000 ppm CO(2) and drought stress). This was supported by the relative expression of the aflR gene in these treatments. This study suggests that the choice of the biocontrol strains, for pre- or post-harvest control, needs to take into account their resilience in CC-related abiotic conditions to ensure that control of AFB(1) contamination can be conserved.
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spelling pubmed-68560842019-11-29 Resilience of Biocontrol for Aflatoxin Minimization Strategies: Climate Change Abiotic Factors May Affect Control in Non-GM and GM-Maize Cultivars Gasperini, Alessandra Marcon Rodriguez-Sixtos, Alicia Verheecke-Vaessen, Carol Garcia-Cela, Esther Medina, Angel Magan, Naresh Front Microbiol Microbiology There has been significant interest in the development of formulations of non-toxigenic strains of Aspergillus flavus for control of toxigenic strains to reduce the aflatoxin B(1) (AFB(1)) contamination of maize. In the future, climate change (CC) abiotic conditions of temperature (+2–4°C), CO(2) (existing levels of 400 vs. 800–1,200 ppb), and drought stress will impact on the agronomy and control of pests and diseases. This study has examined (1) the effect of two-way interacting factors of water activity × temperature on colonization and AFB(1) contamination of maize cobs of different ripening ages; (2) the effect of non-toxigenic strains of A. flavus (50:50 inoculum ratio) on relative control of toxigenic A. flavus and AFB(1) contamination of ripening cobs; (3) post-harvest control of AFB(1) by non-toxigenic strains of A. flavus in non-GM and isogenic GM maize cultivars using the same inoculum ratio; and (4) the impact of three-way interacting CC factors on relative control of AFB(1) in maize cobs pre-harvest and in stored non-GM/GM cultivars. Pre-harvest colonization and AFB(1) production by a toxigenic A. flavus strain was conserved at 37°C when compared with 30°C, at the three ripening stages of cob development examined: milk ripe (R3), dough (R4), and dent (R5). However, pre-harvest biocontrol with a non-toxigenic strain was only effective at the R3 and R4 stages and not at the R5 stage. This was supported by relative expression of the aflR regulatory biosynthetic gene in the different treatments. When exposed to three-way interacting CC factors for control of AFB(1) pre-harvest, the non-toxigenic A. flavus strain was effective at R3 and £4 stages but not at the R5 stage. Post-harvest storage of non-GM and GM cultivars showed that control was achievable at 30°C, with slightly better control in GM-cultivars in terms of the overall inhibition of AFB(1) production. However, in stored maize, the non-toxigenic strains of A. flavus had conserved biocontrol of AFB(1) contamination, especially in the GM-maize cultivars under three-way interacting CC conditions (37°C × 1,000 ppm CO(2) and drought stress). This was supported by the relative expression of the aflR gene in these treatments. This study suggests that the choice of the biocontrol strains, for pre- or post-harvest control, needs to take into account their resilience in CC-related abiotic conditions to ensure that control of AFB(1) contamination can be conserved. Frontiers Media S.A. 2019-11-08 /pmc/articles/PMC6856084/ /pubmed/31787944 http://dx.doi.org/10.3389/fmicb.2019.02525 Text en Copyright © 2019 Gasperini, Rodriguez-Sixtos, Verheecke-Vaessen, Garcia-Cela, Medina and Magan. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
spellingShingle Microbiology
Gasperini, Alessandra Marcon
Rodriguez-Sixtos, Alicia
Verheecke-Vaessen, Carol
Garcia-Cela, Esther
Medina, Angel
Magan, Naresh
Resilience of Biocontrol for Aflatoxin Minimization Strategies: Climate Change Abiotic Factors May Affect Control in Non-GM and GM-Maize Cultivars
title Resilience of Biocontrol for Aflatoxin Minimization Strategies: Climate Change Abiotic Factors May Affect Control in Non-GM and GM-Maize Cultivars
title_full Resilience of Biocontrol for Aflatoxin Minimization Strategies: Climate Change Abiotic Factors May Affect Control in Non-GM and GM-Maize Cultivars
title_fullStr Resilience of Biocontrol for Aflatoxin Minimization Strategies: Climate Change Abiotic Factors May Affect Control in Non-GM and GM-Maize Cultivars
title_full_unstemmed Resilience of Biocontrol for Aflatoxin Minimization Strategies: Climate Change Abiotic Factors May Affect Control in Non-GM and GM-Maize Cultivars
title_short Resilience of Biocontrol for Aflatoxin Minimization Strategies: Climate Change Abiotic Factors May Affect Control in Non-GM and GM-Maize Cultivars
title_sort resilience of biocontrol for aflatoxin minimization strategies: climate change abiotic factors may affect control in non-gm and gm-maize cultivars
topic Microbiology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6856084/
https://www.ncbi.nlm.nih.gov/pubmed/31787944
http://dx.doi.org/10.3389/fmicb.2019.02525
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