RAPID AND EFFICIENT TRANSFORMATION OF DIPLOID MEDICAGO-TRUNCATULA ANDMEDICAGO-SATIVA SSP FALCATA LINES IMPROVED IN SOMATIC EMBRYOGENESIS

We describe a simple and efficient protocol for regeneration-transform ation of two diploid Medicago lines: the annual M. truncatula R108-1(c 3) and the perennial M. sativa ssp. falcata (L.) Arcangeli PI.564263 s elected previously as highly embryogenic genotypes. Here, embryo regen eration of R108-1 to complete plants was further improved by three suc cessive in vitro regeneration cycles resulting in the line R108-1(c3). Agrobacterium tumefaciens-mediated transformation of leaf explants wa s carried out with promoter-gus constructs of two early nodulins (MsEn od12A and MsEnod12B) and one late nodulin (Srglb3). The transgenic pla nts thus produced on all ex plants within 3-4 months remained diploid and were fertile. This protocol appears to be the most efficient and f astest reported so far for leguminous plants.