Plant & Animal Genome V Conference
Town & Country Hotel, San Diego, CA, January 12-16, 1997.
PAG-V: P347 - RNA-MEDIATED VIRUS RESISTANCE IN TRANSGENIC SUGARCANE
P347
RNA-MEDIATED VIRUS RESISTANCE IN TRANSGENIC SUGARCANE
INGELBRECHT, IVAN L.(1), James E. Irvine(2), Erik T. Mirkov(2)
1. Texas A&M Agricultural Experiment Station, Dept. of Plant Pathology and Microbiology, 2415 E. Hwy 83, Weslaco Texas 78596
2. Texas A&M Agricultural Experiment Station, Dept. of Soil and Crop Sciences, 2415 E. Hwy 83, Weslaco Texas 78596
Sugarcane mosaic virus (SCMV) and sorghum mosaic virus (SrMV) strains occur in most parts of the world where sugarcane is grown and can cause significant yield losses. SCMV and SrMV belong to the Potyvirus group and have a single-stranded RNA genome of plus sense polarity. Upon infection, this RNA molecule is translated into a polyprotein which is cleaved into its individual gene products. Virus resistant plants can be obtained through genetic engineering by expressing transgenes that code for untranslatable viral RNA species. To obtain virus resistant sugarcane plants, an untranslatable form of the SrMV strain H coat protein gene was fused to the maize ubiquitin promoter, in sense and antisense orientation, and used in biolistic co-transformation experiments with the bar or the nptII gene. More than 500 plants were regenerated on selective medium and screened for resistance by repeated inoculation with SrMV strain H. The transgene integration pattern was determined for over 300 of these plants. So far, 39 different integration patterns have been identified, representing independent transformation events. Several plants with unique integration patterns were fully susceptible to SrMV infections, two plants with the same pattern could not be infected and still other groups had both susceptible and resistant plants. Plants resistant to SrMV strain H were also resistant to the closely related SrMV strains I and M but not to the distantly related SCMV strains A, D and E. Molecular studies to determine the basis for this resistance will be presented.