Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 7/14/1996
Publication Date: N/A
Technical Abstract: A Magnaporthe grisea cultivar specificity gene toward rice cultivar CO39 was previously mapped to one arm of chromosome 1 between RFLP markers CH5-120H and 5-10-F (Smith, J.R. and S.A. Leong. 1993. Theor.Appl.Genet. 88:901-908). These RFLP markers map 11.6 and 17.2 cM, respectively, on either side of AVRCO39. Using Achilles' cleavage methods CH5-120H and 5-10-F were shown to be separated by 600 kb. A chromosome walk to AVR1-CO39 was initiated from these flanking RFLP markers. Over 500kb have been covered in 20 walking steps. Cosmid clones cosegregating with AVR1-CO39 have been identified and selected clones obtained from the walk were shown to confer avirulence on rice variety CO39 but not 51583 when introduced by transformation into the virulent M.grisea strain Guy11. The DNA conferring avirulence has been delimited to a 3.7 kb region. Hybridization studies of DNA of the virulent M.grisea strain Guy11 indicates that approximately 15 kb of DNA at the AVR1- CO39 locus is deleted and that a repetitive DNA species is present at or near the deletion breakpoint. This deletion probably eliminated part or all of the AVR1-CO39 gene from the Guy11 genome.