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

Author
item Leong, Sally
item FARMAN, MARK - UNIVERSITY OF KENTUCKY
item PUNEKAR, NARAYAN - INDIAN INSTITUTE OF TECH.
item YUAN, WALTER - UNIVERSITY OF WISCONSIN
item ETO, YUKIKO - KOBE UNIVERSITY, JAPAN
item MAYAMA, SHIGYUKI - KOBE UNIVERSITY, JAPAN
item TOSA, YUKIO - KOBE UNIVERSITY, JAPAN

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 8/4/1998
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. Achromosome walk of 600 kb was completed in 20 steps and revealed that the relationship of genetic to physical distance in this chrosomal 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 sequence surrounding the ATG of the third open reading frame matched four out of five of the conserved bases found in fungal translational start sites and contained a hydrophobic amino terminus puntuated by a lysine in position two and two putative cleavage sites for removal of the signal peptide. A 4th open reading frame was identified on the opposite strand, however, the sequence surrounding the ATG contained only 2 matches with the fungal consensus sequence. Site-directed mutations in all 3 open reading frames on one strand were created in order to assess their role in avirulence. 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 lariate 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.