Genetic Engineering in Rice Plants

Abstract

Recently, gene transfer into higher plants has made it possible to analyse foreign gene expression in transgenic rice plants. We have constructed a chimeric gene consisting of the promoter, 1st exon, and 1st intron of a maize polyubiquitin gene (Ubi-1) and the coding sequence of the bar gene from Streptomyces hygroscopicus. This construct was transferred into rice protoplasts via electroporation. Transgenic plants grown in a greenhouse were resistant to both bialaphos and phosphinotliricine at a dosage lethal to untransformed control plants. Western blot analysis and enzymatic assays verified expression of the active bar gene-product. Apparent Mendelian segregation for bialaphos resistance and enzymatic activity in T1 progeny of primary transformants are consistent with heritable transmission of the introduced marker gene. When rice plants expressing a bar gene under the control of the maize polyubiquitin promoter were subjected to mycelium of the sheath blight disease pathogen, Rhizoctonia solani, followed by bialaphos treatment, only transgenic plants survived and did not show the disease symptoms. Thus, bialaphos resistant rice plants could be useful for prevention of fungal pathogen attack.