[The cDNA cloning of conarachin gene and its expression in developing peanut seeds]

In order to clone the genes of peanut seed storage proteins, a cDNA library of mid-maturation stage cotyledons of peanut (Arachis hypogaea L. Shanyou 523) was constructed. After immunoscreening with polyclonal antibody against conarachin from peanut seeds, two cDNA sequences named Ahy alpha and Ahy beta of conarachin genes were obtained. BLAST these sequences in GenBank showed that they share high homology with the genes of legume 7S globulins. One of the sequences (Ahy beta) was found to be identical to part of the published complete cDNA sequence of the peanut allergen, Ara h1 p17. The other fragment (Ahy alpha) was almost identical to parts of the published complete cDNA sequence of the peanut allergen, Ara h1 p41b. Results of southern analysis show that they belong to a small gene family (the result is not shown). These sequences were expressed only in developing peanut seeds. To isolate the genes involved in seed storage protein and to understand the gene expression during peanut seed development, the sequences of 414 ESTs were determined and further analyzed by BLAST searches and categorized functionally. Five rESTs (representative ones) of arahin, two rESTs of conarachin and six rESTs of conglutin-like proteins were isolated. 17.0% of total transcripts isolated in this study are involved in peanut seed storage proteins.