2012 journal article
Diversity of Seed Storage Proteins of Arachis hypogaea and Related Species
CROP SCIENCE, 52(4), 1676–1688.
ABSTRACTThe diversity of seed storage proteins of cultivated peanut (Arachis hypogaea L.) was studied by analyzing nucleotide sequences encoding 2S, 7S, and 11S seed storage proteins. Alignments of sequences were performed using ClustalX, and similarity between aligned sequences was established by pairwise comparison using AlignX. Three homology groups of 2S proteins were identified, which were further divided into three, three, and two subgroups. Similarly, three homology groups of 7S proteins contained two, two, and one subgroups; and five homology groups of 11S proteins contained five, five, five, three, and two subgroups. Primer pairs were identified that allowed each member of the respective homology group to be selectively amplified by polymerase chain reaction using template complementary DNA or genomic DNA from A. hypogaea. This permitted most subgroup members to be distinguished. Peanut, like other legumes, contains small gene families encoding each type of seed storage protein. However, the diversity among these was greater than in other legume species, which reflects the allotetraploid nature of A. hypogaea. Polymerase chain reaction amplifications from diploid species were used to deduce which protein subgroup originated from the A genome and which were from the B genome. Of the 26 diploid peanut species studied, only A. duranensis Krapov. and W.C. Greg. (A genome) and A. ipaensis Krapov. and W.C. Greg. (B genome) contained the correct complement of seed storage protein coding regions. This is consistent with the hypothesis that the center of origin of the allotetraploid was southern Bolivia.