Variation and genomic polymorphism of lectin-related proteins in Lima bean (Phaseolus lunatus L.) seeds

Variation of the lectin and the two lectin-related proteins, AIL (α-amylase inhibitor-like) and ARL (arcelin-like) was examined in wild and cultivated accessions of Lima bean (Phaseolus lunatus L.) using electrophoresis of total seed proteins, immunoblot and RFLP analysis of lectin-related genes. Results confirm that divergence of the two major Lima bean gene pools, Andean and Mesoamerican, also apply to this protein family. All three members of the family are present in both gene pools, with differences in size, abundance and composition between gene pools, giving the possibility to distinguish Andean from Mesoamerican lectin pattern types. Both patterns show some variants, such as lack of lectin or its presence as an abundant protein. The observed variation reflects, at least in part, into genomic polymorphism. The presence of arcelin- and α-amylase-related proteins in Lima bean could represent a tool to increase our knowledge in the evolution of the lectin family in Phaseolus species.