Phytophthora sojae genome contains tandem repeat sequences which vary from strain to strain

• Published in: Fungal genetics and biology 1996-03, Vol.20 (1), p.43-51
• Main Authors: Mao, Y, Tyler, B.M
• Format: Article
• Language: English
• Subjects: amplification; Base Sequence; chromosome mapping; chromosomes; genes; Genetic Variation; genome; Genome, Fungal; Genomic Library; genomic subtraction hybridization; Molecular Sequence Data; Nucleic Acid Hybridization; pathotypes; Phytophthora; Phytophthora - genetics; repetitive sequences; Repetitive Sequences, Nucleic Acid; ribosomal DNA; ribosomal RNA; Species Specificity; strain differences
• ISSN: 1087-1845; 1096-0937
• DOI: 10.1006/fgbi.1996.0008

The oömycete Phytophthora sojae causes root and stem rot of soybean. In P. sojae, 37 cultivarspecific physiological races have been reported with different reactions against 13 single dominant resistance genes in soybean. Recent genetic studies have demonstrated that the P. sojae-soybean interaction follows Flor's gene-for-gene model. Genomic subtraction was carried out to isolate race-specific DNA sequences possibly including avirulence genes. DNA from a race 1 isolate was subtraction-enriched with the DNAs from race 19 and race 22 isolates. The enriched DNAs were used to differentially screen a P. sojae genomic library. Characterization of the clones obtained identified repetitive sequences with variable copy numbers among isolates. Five of these repetitive sequences were tandemly repeated and were localized on single chromosomes. The sixth corresponded to the ribosomal RNA genes. These observations suggest that gene amplification could contribute to the generation of genetic diversity in P. sojae. Enriched sequences corresponding to avirulence genes were not detected.