Genotype-Driven Proteomic Diversity in Macadamia Nuts: Implications for Allergenicity, Nutritional Quality, and Breeding Strategies

Macadamia nuts are valued for their nutritional content, yet little is known about the factors that affect nut quality or the genetic contributions of parental lines. This study optimized a protein extraction protocol for lipid-rich macadamia nuts and applied SDS-PAGE and mass spectrometry-based proteomics to characterize nuts with known parental origin. A total of 431 high-confidence proteins were identified, with seed storage proteins (SSPs), primarily vicilin- and legumin-like globulins, comprising nearly 50% of total protein abundance. Distinct SDS-PAGE banding patterns among genotypes, including within maternal lines, indicated significant paternal influence on protein profiles. Correlation analysis confirmed that specific gel bands reveal the abundance of allergenic SSPs. Moreover, sequence coverage and post-translational modifications of SSPs varied across genotypes, indicating molecular divergence. These findings provide insights into the genetic basis of nut protein composition, inform allergenicity risk assessment, and support breeding strategies aimed at improving macadamia nut quality and developing hypoallergenic cultivars.