Submitted to: Plant and Animal Genome Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 1/15/2005
Publication Date: 1/15/2005
Citation: Jia, Y., Winston, E.M., Singh, P., Zhou, E., Wamishe, Y., Jia, M.H., Correll, J., Rutger, J.N. 2005. Molecular coevolution of rice resistance gene pi-ta and the corresponding Magnaporthe grisea avirulance gene avr-pita [abstract]. In: Plant and Animal Genome Conference Proceedings. p. 74.
Technical Abstract: Understanding the population biology of both resistance genes and avirulence genes of rice blast fungus will allow the development of strategies to control rice blast disease. The Pi-ta gene in rice is effective in preventing the infection of M. grisea races containing the corresponding avirulence gene AVR-Pita. Pi-ta is a single copy gene located at the centromere of chromosome 12. Pi-ta encodes a predicted cytoplasmic protein with a centrally located nucleotide-binding site and a leucine-rich domain at its carboxyl terminus. AVR-Pita is a metalloprotease located near the teleometric region of chromosome 3 of M. grisea. Pi-ta appears to recognize AVR-Pita directly inside the host cell, triggering effective defense response. A survey of rice germplasm (in different rice production regions) has identified rice cultivars containing four haplotypes of the Pi-ta allele, one resistant (Pi-ta) haplotype and three susceptible (pi-ta) haplotypes. Pi-ta confers resistance to the major US M. grisea pathotypes; the polymorphic regions of Pi-ta that distinguish resistant and susceptible alleles of Pi-ta were successfully used for the development of dominant and codominant markers for marker assisted Pi-ta incorporation. Survey of the pathogen population in the US indicates that the deletion of the AVR-Pita allele in some "race -shift" isolates of M. grisea can defeat protection provided by Pi-ta. Race-shift isolates have been selected and recovered from the field. Whether such isolates can prevail and cause economic losses depends on the role of AVR-Pita in both pathogenesis and pathogen fitness in the environment. Progress on the development of molecular strategies to control rice blast disease will be presented.