Peanuts that keep aflatoxin at bay: a threshold that matters

Sharma, K K and Pothana, A and Prasad, K and Shah, D and Kaur, J and Bhatnagar, D and Chen, Z Y and Raruang, Y and Cary, J W and Rajasekaran, K and Sudini, H and Bhatnagar-Mathur, P (2017) Peanuts that keep aflatoxin at bay: a threshold that matters. Plant Biotechnology Journal. pp. 1-10. ISSN 14677644

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Abstract

Aflatoxin contamination in peanuts poses major challenges for vulnerable populations of sub-Saharan Africa and South Asia. Developing peanut varieties to combat preharvest Aspergillus flavus infection and resulting aflatoxin contamination has thus far remained a major challenge, confounded by highly complex peanut–Aspergilli pathosystem. Our study reports achieving a high level of resistance in peanut by overexpressing (OE) antifungal plant defensins MsDef1 and MtDef4.2, and through host-induced gene silencing (HIGS) of aflM and aflP genes from the aflatoxin biosynthetic pathway. While the former improves genetic resistance to A. flavus infection, the latter inhibits aflatoxin production in the event of infection providing durable resistance against different Aspergillus flavus morphotypes and negligible aflatoxin content in several peanut events/lines well. A strong positive correlation was observed between aflatoxin accumulation and decline in transcription of the aflatoxin biosynthetic pathway genes in both OE-Def and HIGS lines. Transcriptomic signatures in the resistant lines revealed key mechanisms such as regulation of aflatoxin synthesis, its packaging and export control, besides the role of reactive oxygen species-scavenging enzymes that render enhanced protection in the OE and HIGS lines. This is the first study to demonstrate highly effective biotechnological strategies for successfully generating peanuts that are near-immune to aflatoxin contamination, offering a panacea for serious food safety, health and trade issues in the semi-arid regions.

Item Type: Article
Divisions: Research Program : Genetic Gains
Research Program : Innovation Systems for the Drylands (ISD)
CRP: CGIAR Research Program on Grain Legumes
Uncontrolled Keywords: Aflatoxin, peanut, Aspergillus flavus, food safety, mycotoxins, host-induced gene silencing, defensins, Aflatoxin contamination, food security
Subjects: Others > Genetic Engineering
Others > Plant Genetics
Mandate crops > Groundnut
Others > Genetics and Genomics
Others > Aflatoxins
Depositing User: Mr Ramesh K
Date Deposited: 20 Oct 2017 07:59
Last Modified: 04 Jan 2018 08:40
URI: http://oar.icrisat.org/id/eprint/10218
Official URL: http://dx.doi.org/10.1111/pbi.12846
Projects: UNSPECIFIED
Funders: UNSPECIFIED
Acknowledgement: This work was partly supported by the CGIAR research programme on Grain Legumes and USAID funded CGIAR linkage grant. We thank Pradeep Reddy, Kedarinath, Rahul, Mamta Sharma, Balakrishna, Srivani, Sahithi, D. Srinivas Reddy and Cindhuri for assistance with various experiments, and Eng Hwa and P. Janila for critical review and inputs on the manuscript. The support from PS Rao, Vengal Reddy, Amit Chakravarty and Jemima for editing and pictures is acknowledged. AP is thankful to the Department of Science & Technology, Government of India, for graduate research fellowship. The authors declare no conflict of interest. The supplementary materials contain additional data.
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