Design and construction of a versatile system for the expression of foreign genes in plants.

We have built a series of vectors to allow the constitutive or light-regulated expression of foreign genes in plants. These vectors carry expression cassettes consisting of either the cauliflower mosaic virus 35S promoter or the pea rbcS-E9 promoter, a multiple cloning site derived from M13um20, and the rbcS-E9 polyadenylation site. These cassettes have been incorporated into pBR322-based or RK2-based replicons to facilitate direct DNA uptake or Agrobacterium tumefaciens-mediated gene transfer. Their application for the expression of a bacterial gene is described.