Agrobacterium-Mediated Transformation and Expression of Foreign Genes in Medicago truncatula

Abstract

Medicago truncatula Gaertn. (barrel medic) is a pasture legume and a model plant for studying the molecular genetics of the Rhizobium-legume symbiosis. Using the highly regenerable seed line Jemalong 2HA and Agrobacterium tumefaciens (LBA4404), Medicago truncatula can be reliably transformed. The binary vector utilised was pBI121 containing the nptII and uidA genes under the control of the NOS and CaMV 35S promoters, respectively. Kanamycin-resistant embryogenic calli were produced from 17% of the initial leaf explants and on average each one of these embryogenic calli produced a single regenerated plantlet. Regenerated plants showed varying gene copy number and gene location. GUS activity was detected in roots, stems and leaves. The progeny of a regenerated plant containing a single gene copy segregated in a Mendelian fashion. This study confirms the value of Jemalong 2HA for producing transgenic plants for biological and agricultural studies.