A FUNGAL CHITINASE GENE FROM RHIZOPUS-OLIGOSPORUS CONFERS ANTIFUNGAL ACTIVITY TO TRANSGENIC TOBACCO

We have studied whether a chitinase involved in cell autolysis of a fi lamentous fungus, Rhizopus oligosporus, can operate as an antifungal d efense system in tobacco. The chil gene was introduced into tobacco by the Agrobacterium tumefaciens leaf disc system. Among 22 transgenic t obacco plants, 2 were selected and their individual homozygous progeny , Tch1-1 and Tch2-1, were studied. Chitinase activity in the extracts of young leaves from Tch 1-1 or Tch2-1, in which the chil gene product was detected by Western blot analysis, was three- to four-fold higher than that from the control plants. A fungal infection assay on the le aves infected with the discomycete pathogens Sclerotinia sclerotiorum and Botryrtis cinerea revealed that the symptoms observed with these t wo were remarkably suppressed as compared with the control leaves.