Construction of Genomic Library for Leucaena Leacocephala and Isolation of a Gene Enco ding Seed Storage Protein

Leucaena leucocephala (Mimosaceae), a tropical plant, has been a very important forage for livestock in tropical area. The leaves and seeds contain proteins up to 30% and 33% of the dry weight respectively. We have been interested in studying these proteins and expression of genes encoding these proteins and constructed the genomic library. Total DNA from leaves of L. leucocephala was isolated and digested partially with Sau3A. Bacterophage lambda EMBL3 was used as a cloning vector. Recombinant molecules were packaged into viable phage particles in vitro and the yield of recombinant phages was 3.5×106 pfu. In order to understand the homology between genes encoding seed storage protein from L. leucocephala and soybean, the library was amplified and screened with a gene encoding the α'-subunit of the soybean 7S storage protein. Four positive clones were obtained and three of them were chosen for further analysis. Physical mapping and partial DNA sequence have revealed the homology between genes encoding storage proteins of L. leucocephala and soybean.