University of Arkansas, Fayetteville


Fungicides are expensive, dangerous, and can be harmful to the environment, but they are often necessary for profitable farming operations. New technologies may soon allow farmers to replace these chemicals with genetically engineered plants producing antifungal enzymes that degrade fungal cell walls. To explore this option, a Paenbacillus chitosanase gene was cloned, sequenced, and modified for plant expression. The modified gene was delivered to tobacco (Nicotiana tabacum L cv. Xanthine) leaf disks via Agrobacterium tumenfaciens-mediated transformation. The putative GMOs were tested for transgene integration, transcription, and translation. Confirmed transformants were then screened for enhanced responses to a Rhizoctonia solani cell wall preparation by measuring time-course production of hydrogen peroxide, phenyalanine ammonia lyase, and peroxidase. These compounds play roles at different points in a pathogensis-related signal transduction pathway and, thus, allow for an initial assessment of the global defense response. Preliminary data suggest that transgenic tobacco constitutively expressing a Paenbacillus chitosanase may activate pathogenesis-related defense responses more quickly than wild type tobacco.