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Title: AVR1-CO39, A CULTIVAR SPECIFICITY GENE FROM MAGNAPORTHE GRISEA

Author
item Leong, Sally
item FARMAN, MARK - UNIVERSITY OF WISCONSIN
item PUNEKAR, NARAYAN - UNIVERSITY OF WISCONSIN
item YUAN, WALTER - UNIVERSITY OF WISCONSIN
item MAYAMA, SHIGYUKI - KOBE UNIVERSITY, JAPAN
item NAKAYASHI, HITOSHI - KOBE UNIVERSITY, JAPAN
item TOSA, YUKIO - KOBE UNIVERSITY, JAPAN

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/15/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: A gene conferring cultivar-specific interactions with rice cultivar CO39 was isolated from Magnaporthe grisea strain 2539 using a map-based cloning approach. A chromosome walk of 600 kb was completed in 20 steps and revealed that the relationship of genetic to physical distance in this chromosomal region varied by up to fourteen-fold. The AVR1- CO39 locus was delimited to a 1.05 kb region by subcloning and transformation of Guy11, a strain virulent on CO39, to avirulence. DNA sequence analysis revealed four small open reading frames of 45, 77, 89 and 69 amino acids in length.The translational start codon of each open reading frame was converted to TTT; mutations in open reading frames 1 and 3 led to a loss of avirulence. Frameshift mutations in open reading frames 1 and 3 also led to a loss of avirulence while mutation of open reading frame 2 did not. Taken together, these data suggest a role for open reading frames 1 and 3. The absence of splice site and a lariat sequence as well as a putative TATA element immediately upstream of the ATG of open reading frame 1 may indicate that open reading frame 1 overlaps sequences critical to the promotion of transcription of AVR1-CO39. Transcript mapping is underway to investigate this possibility. The distribution of AVR1-CO39 was investigated by probing genomic DNA from a large sample of host-specific forms of M.grisea The data to date indicate that isolates infecting rice, Digitaria and wheat lack AVR1-CO39 while about half of the isolates surveyed from Eleucine contain homologs of the gene. A detailed analysis of the AVR1-CO39 locus from rice isolate Guy11 indicated that at least 20 kb of DNA corresponding to and containing the AVR1-CO39 locus of 2539 was absent.