Avuthu, T and Sanivarapu, H and Prasad, K and Shama, N and Sudini, H K and Yogendra, K (2025) Unravelling Aflatoxin Resistance in Groundnut: Metabolomic and Genetic Mechanisms of Secondary Cell Wall Reinforcement. In: Advances in Arachis through Genomics and Biotechnology (AAGB-2025), 23-25 March 2025, Novotel, Goa, India.
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Aflatoxin contamination caused by Aspergillus flavus presents a significant challenge to groundnut (Arachis hypogaea) production, endangering food safety and human health. Despite extensive research, the molecular mechanisms underlying resistance to aflatoxin contamination remain unclear. This study conducted a comparative metabolomics analysis on two contrasting groundnut genotypes-resistant (55-437) and susceptible (TMV-2)-to identify key metabolites and biochemical pathways associated with resistance. Metabolite profiling using liquid chromatography–high-resolution mass spectrometry (LC-HRMS) revealed significant metabolic differences between the two genotypes. Notably, resistance-related metabolites, particularly hydroxycinnamic acid amides (HCAAs) and lignins, were highly enriched in the resistant genotype. These compounds contribute to secondary cell wall thickening, acting as a physical barrier against fungal penetration. Histochemical staining confirmed increased lignin and HCAA deposition in the resistant genotype upon pathogen infection. In addition to metabolite profiling, gene expression analysis was conducted to understand the molecular basis of resistance. Quantitative real-time PCR (qRT-PCR) demonstrated significant pregulation of key phenylpropanoid biosynthetic genes in the resistant genotype, including PAL, 4CL, CCR2, CAD1, ACT, CHS, DFR, and FLS. The higher expression of these genes correlated with increased accumulation of secondary metabolites that reinforce structural barriers against A. flavus infection. Furthermore, flavonoids, fatty acids, alkaloids, and terpenoids also exhibited differential accumulation, suggesting their potential role in enhancing resistance. These findings indicate a genotype-specific metabolic reprogramming that strengthens groundnut defense mechanisms against fungal invasion and aflatoxin contamination. This study highlights secondary cell wall thickening as a crucial mechanism conferring resistance to A. flavus in groundnut. The enhanced deposition of lignins and HCAAs, along with the activation of key biosynthetic pathways, strengthens the plant’s structural defenses, limiting pathogen entry and aflatoxin production. Additionally, the involvement of flavonoids, fatty acids, and alkaloids in resistance suggests that multiple biochemical pathways contribute to aflatoxin defense. These insights provide a foundation for developing groundnut cultivars with improved resistance through targeted breeding and genetic engineering strategies. By integrating metabolomics and gene expression analyses, this research advances the understanding of aflatoxin resistance mechanisms and offers new avenues for enhancing groundnut resilience and food safety.
| Item Type: | Conference or Workshop Item (Speech) |
|---|---|
| Divisions: | Global Research Program - Accelerated Crop Improvement |
| CRP: | UNSPECIFIED |
| Uncontrolled Keywords: | Aflatoxin resistance, Aspergillus flavus, Groundnut (Arachis hypogaea), Secondary cell wall thickening, Phenylpropanoids |
| Subjects: | Mandate crops > Groundnut Others > Aflatoxins |
| Depositing User: | Mr Nagaraju T |
| Date Deposited: | 09 Jul 2025 04:02 |
| Last Modified: | 09 Jul 2025 04:02 |
| URI: | http://oar.icrisat.org/id/eprint/13216 |
| Acknowledgement: | UNSPECIFIED |
| Links: | |
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