Transfer of the arcelin-phytohaemagglutinin-α amylase inhibitor seed protein locus from tepary bean (Phaseolus acutifolius A. Gray) to common bean (P. vulgaris L.)

Phaseolus vulgaris cultivars ICA Pijao, Rojo and 5-593 were crossed to the P. acutifolius wild accessions G40199 and an F2 selection from a cross between G40199 and cultivated brown seeded unnamed tepary accession (designated Brown Tepary). G40199 is highly resistant to the two major bruchid pests of common bean: Acanthoscelides obtectus and Zabrotes subfasciatus, but the mechanism for resistance is unknown. Interspecific F1 hybrids with the three common bean parents were generated via., embryo rescue. Recovered hybrids were from ICA-Pijao and 5-593 and were highly sterile and were backcrossed as females to ICA Pijao. Seeds from the BC1F2 plants were screened for protein phenotype and the inheritance of seed storage protein profiles contributed by the tepary bean parents. Most of the F 1 hybrids demonstrated introgression of a lectin-like protein of 33 kDa that was found in G40199, but not in the Brown Tepary or common bean lines. This lectin related protein complex was similar to the arcelin (ARL), phytohaemagglutinin (PHA) and α-amylase inhibitor (α-AI) seed storage protein family of P. acutifolius. Genomic DNA sequences from wild accession G40199 and the interspecific hybrids revealed a high sequence similarity to ARL2 and α-AI genes of P. acutifolius. Because lectin-related proteins of P. acutifolius have been associated with strong resistance to bruchids, we hypothesize that these proteins alone or in conjunction with other factors, may contribute to the disputed bruchid resistance mechanism in G40199. © 2009 Asian Network for Scientific Information.