Submitted to: Journal of Horticultural Science and Biotechnology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 11/2/2012
Publication Date: 3/4/2013
Citation: Mattison, C.P., Tarver, M.R., Florane, C.B., Graham, C.J. 2013. Temporal expression of pecan allergens during nut development. Journal of Horticultural Science and Biotechnology. 88-2:173-178. Interpretive Summary: Pecan nuts and other tree nuts are among a group of eight foods that most commonly cause food allergy. Pecan nuts and other tree nuts contain proteins that can cause severe allergic reactions in susceptible individuals. The accumulation of these allergy-causing proteins in nuts requires expression of certain genes at specific times during nut development. We evaluated the timing of expression of three genes encoding food allergen proteins during pecan nut development. Each of the allergen genes was expressed at relatively low levels within the developing seed pod early in development, and we observed a substantial increase in accumulation of each of the three allergen messenger RNAs as the nuts matured. Our results better characterize pecan allergen gene expression, and may allow the development of molecular methods to reduce or eliminate pecan allergens from nuts.
Technical Abstract: Pecan nuts and other tree nuts are among a group of eight foods that most commonly cause food allergy. The growth of pecan nuts is a highly complex process orchestrated by the temporal and spatial expression of specific genes. Three conserved seed-storage proteins from the prolamin and cupin superfamilies; including 2S albumin, 7S vicillin, and 11S legumins are commonly identified as food allergens from nuts. Transcript levels for pecan 2S albumin (Car i 1), 11S legumin (Car i 4), and 7S vicillin homolog (Car i 7S) were investigated in developing nuts from the Desirable and Sumner cultivars, using quantitative Real-Time PCR (qRT-PCR). Each of the allergen transcripts was detected at relatively low levels within the developing seed pod during early nut out-growth. We observed a several thousand-fold increase in accumulation of each of the three allergen messenger RNAs, as nut growth continued and the seed pod filled. This was followed by a decline in message level during nut maturation. In most cases we observed similar levels of allergen gene expression in the Desirable and Sumner cultivars, although Car i 1 and Car i 4 transcripts varied slightly. The findings presented here provide evidence that expression of genes encoding allergenic seed storage proteins is temporally regulated, and methods targeting transcriptional regulation may be used in the future to reduce or eliminate pecan allergens from nuts.