Development of peanut cultivars with reduced aflatoxin B1 contamination

Overview

This research program focuses on developing transgenic peanut cultivars that carry elevated levels of the antifungal proteins glucanase and chitanase to combat Aspergillus flavus infection and reduce aflatoxin B1 (AFB1) accumulation in peanuts. Aflatoxin contamination is a serious food safety and economic issue affecting peanut producers, processors, and consumers worldwide. By introducing rice chitinase and alfalfa β-1,3-glucanase genes into a commercial peanut variety (Tifguard), the program aims to deliver cultivars with built-in fungal resistance and significantly lower toxin levels. A novel immunochromatography (ICG) strip test using monoclonal antibodies is also being developed to detect nanogram concentrations of AFB1 directly in host cells.

Technical specifications

Key features and methods:

• Standardized somatic embryogenesis and regeneration protocol for the Tifguard peanut variety using 15 mg/L 2,4-D, yielding up to 5.5 somatic embryos per explant
• Agrobacterium-mediated transformation with plasmid constructs pCAMBAR Glu289 (glucanase) and pCAMBAR Chi11 (chitinase)
• Transgenic confirmation by qRT-PCR for gene integration and SDS-PAGE and Western blot for protein expression
• Glucanase activity measured at 80,000–90,000 μL/mL in transgenics versus 30,000–40,000 μL/mL in controls
• Chitinase activity measured at 50,000–80,000 μL/mL in transgenics versus 20,000–30,000 μL/mL in controls
• Protein detection at 12 kDa (glucanase) and 20 kDa (chitinase)
• AFB1 quantification by HPLC and qualitative detection by immunochromatography strip test using monoclonal antibodies (mouse IgG1/k, clone 6A10)
• Immunocytochemical localization of AFB1 within cell organelles, a novel approach for transgenic peanuts

Technology readiness level

The program has completed in vitro validation, demonstrating successful gene integration, elevated antifungal protein expression, and reduced AFB1 levels in transgenic peanut lines compared to controls. The next phase involves in vivo cultivation of R1 generation transgenic plants, further gene expression confirmation, colorimetric enzyme assays for resistance screening, and advanced AFB1 detection by HPLC and ICG strip tests. The technology is at an early-to-mid stage of development, with proof-of-concept data established in vitro and field validation and regulatory readiness remaining as future steps.