New discovery unveils natural peanut defence mechanism
Paves the way for disease-resistant varieties
Scientists have uncovered a natural defence mechanism in peanuts that could revolutionise the development of disease-resistant peanut varieties.
Peanuts, a crucial oilseed with economic importance, are particularly susceptible to Aspergillus infection, which can lead to aflatoxin contamination.
Researchers from the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) conducted a groundbreaking study on the innate resistance of select peanut varieties.
Their findings elucidate the biochemical processes responsible for thickening the secondary cell wall, offering enhanced resistance to Aspergillus flavus, the fungus responsible for the infection.
Aflatoxin, a potent carcinogen and toxin, poses a global threat as it accumulates in various food crops, including cereals, oilseeds, pulses, and nuts, due to infection with Aspergillus species.
Economic consequences
The contamination jeopardises food safety and human health and has far-reaching economic consequences.
Governments worldwide enforce strict regulations on allowable aflatoxin levels in food commodities, significantly impacting food markets and export economies, particularly in developing nations.
While existing methods address aflatoxin contamination through physical and chemical means, developing more resilient peanut varieties emerges as the most economically viable solution, tackling the issue at its core.
This breakthrough study provides crucial insights for breeding groundnut varieties with complete resistance to Aspergillus infection in the future.
Dr Jacqueline Hughes, the Director General of ICRISAT, emphasised the organisation’s extensive experience spanning over 50 years in managing aflatoxin contamination.
“ICRISAT’s efforts, from low-cost aflatoxin detection assays to post-harvest management practices, have revitalised export economies, particularly in Malawi. This study is pivotal for advancing research aimed at eliminating the issue at its source, saving cost and effort,” stated Dr Hughes.
ICRISAT research
The researchers at ICRISAT employed a metabolomics-based systems biology approach for the study, revealing the biochemical intricacies behind increased peanut resistance to Aspergillus infection for the first time.
The study establishes a connection between two specific metabolites—hydroxycinnamic acid amides (HCAAs) and lignin precursor levels—and the resistance exhibited by peanut varieties.
These metabolites, found in higher concentrations in the resistant genotype, strengthen the secondary cell wall, creating a formidable physical and chemical barrier against infection.
Global Research Program Director—Accelerated Crop Improvement Dr Sean Mayes expressed optimism about the study’s implications.
“The findings highlight the crucial role secondary thickening of cell walls plays in reducing seed infection in the field. Combining this with other mechanisms could lead us towards producing aflatoxin-free peanuts, ensuring safe, toxin-free food production,” Dr Mayes explained.
Lead author of the study, Dr Yogendra Kalenahalli, introduced the metabolomics-based systems approach, underlining its broader applications beyond peanut breeding.
“This methodology extends beyond breeding more resistant groundnut varieties and can provide a deeper understanding of similar resistance mechanisms across various food crops like cereals, oilseeds, and nuts, highly susceptible to aflatoxin and other mycotoxins,” said Dr Kalenahalli.
ICRISAT is an international organisation headquartered in Hyderabad, Telangana, India. It is committed to developing and improving dryland farming and agri-food systems to address the challenges of hunger, malnutrition, poverty, and environmental degradation affecting the 2.1 billion people living in the drylands of Asia, Sub-Saharan Africa, and beyond.
Featured image: Peanuts are particularly susceptible to Aspergillus infection. Credit: ICRISAT
