The immunodominant human allergen of soybean seeds is a cysteine protease family member called P34 or Gly m Bd 30K. P34 is accumulated at high levels in maturing seeds and in small quantities in vegetative tissues, where it may have a pathogen-resistance role. Among cysteine proteases, P34 is unique in possessing a glycine substitution for an otherwise invariant cysteine in the active site. Among soybean sensitive people, P34 accounts for a large majority of IgE crossreactivity.  Soybean sensitivity is also widespread among farmed animals ranging from pigs to salmon. Human IgE binding epitopes have been mapped, and the allergenic epitopes consist of fourteen distinct sites.

A seed-specific silencing of P34 has been achieved, and homozygous lines completely lacking P34 are now growing in field tests. P34-silenced soybean seeds have identical protein composition and protein/oil ratios compared to the wild type. The P34-silenced lines grow normally and are apparently identical to the wild type in the development of the plant and in the formation of the seed. The protein storage vacuoles that would sequester the P34 protein are not altered in the silenced line. Proteomic analysis of the P34-silenced line in comparison with the wild type demonstrates there are no other collateral changes in protein composition in response to P34 suppression. These results show that it is feasible to use biotechnology to suppress a major human allergen in crops, implying that widespread use of this approach can improve the safety of food for sensitive people.

Selected Publications

Bilyeu K, Ren C, Nguyen HT, Herman E, and Sleper DA. (2009). Association of a four basepair insertion in the P34 gene with the low allergen trait in soybean. The Plant Genome, in press.

Miernyk JA, Johnston ML, Antoine W, Mooney BP, Herman EM. (2009) A Directed-Proteomics Platform for Systems Analysis of Soybean Seed Development. Journal of Integrative Plant Biology. in press

Herman EM 2009. Soybean Food and Feed Allergy. In Modification of Seed Composition to Promote Health and Nutrition (Krishnan, H.B., Ed.), ASA-CSSA-SSSA Publishing, Madison, WI. in press.

Herman EM (2008) Endoplasmic reticulum bodies: Solving the insoluble. Curr. Opinion in Plant Biology. 11:672-679.

Barrows FD. Bellis D, Brown P, Campen J, Dabrowski K, Gatlin III DM, Hardy RW, Herman E, Gongshe H, Krogdahl A, Nelson R, Overturf KE, Rust M, Sealey W, Skonberg D, Souza EJ, Stone D, and Wilson RF. (2008) Expanding the utilization of sustainable plant products in aquafeeds- Fisheries Sci 16:449-455.

Herman E (2008) Mitigation of soybean allergy by development of low allergen content soybeans. Ed. Siantar D, Truckness M, Scott P, and Herman E. Eds. American Chemical Society, Allergy and Mycotoxins; papers from symposium from the 2006 American Chemical Society Annual Meeting. In press

Siantar D, Truckness M, Scott P, and Herman E. Eds. (2008) Allergy and Mycotoxins; American Chemical Society press.

Schmidt MA and Herman EM (2008) Suppression of soybean oleosin produces micro-oil bodies that aggregate into oil body/ER complexes. Molec Plant 1:910- 924.

Schmidt MA,and Herman EM (2008) Proteome rebalancing in soybean seeds can be exploited to enhance foreign protein accumulation. Plant Biotech J 6: 832- 842