Avirulence of Magnaporthe grisea isolate CHL346 on rice cultivar GA25 was studied with 242 ascospore progenies derived from the cross CHL346 x CHL42. Segregation analysis of the avirulence in the progeny population was in agreement with the existence of a single avirulence (Avr) gene, designated as AvrPi15. For mapping the Avr gene, we developed a total of 121 microsatellite DNA markers [simple sequence repeat (SSR)], which evenly distributed in the whole-genome of M. grisea through bioinformatics analysis (BIA) using the publicly available sequence. Linkage analysis of the AvrPi15 gene with these SSR markers showed that six markers on chromosome 6, MS6-1, MS6-2, MS6-3, MS6-7, MS6-8 and MS6-10, were linked to the AvrPi15 locus. To further define the chromosomal location of the AvrPi15 locus, two additional markers, MS6-17 and STS6-6, which were developed based on the sequences of telomeric region 11 (TEL11), were subjected to linkage analysis. The results showed that MS6-17 and STS6-6 were associated with the locus by 3.3 and 0.8 cM, respectively. To finely map the Avr gene, two additional candidate avirulence gene (CAG) markers, CAG6-1 and CAG6-2, were developed based on the gene annotation of the sequence of TEL 11. Linkage analysis of the Avr gene with these two markers revealed that both of them completely cosegregated with the AvrPi15 locus. Finally, this locus was physically mapped into approximately 7.2-kb interval of the TEL11 by BIA using these sequence-ready markers. This is the key step toward positional cloning of the AvrPi15 gene.
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http://dx.doi.org/10.1007/s00122-006-0347-6 | DOI Listing |
J Clin Virol
January 2025
Division of Medical Microbiology and Virology, St. Paul's Hospital, Providence Health Care, Vancouver, British Columbia, Canada; Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada. Electronic address:
Background: Next-generation sequencing (NGS) for Hepatitis B virus (HBV) antiviral resistance (AVR) testing is a highly sensitive diagnostic method, able to detect low-level mutant subpopulations. Our clinical virology laboratory previously transitioned from DNA hybridization (INNO-LiPA) to NGS, initially with the GS Junior System and subsequently the MiSeq. The Oxford Nanopore Technology (ONT) sequencing system was evaluated for HBV resistance testing, with regards to sequencing accuracy and turn-around time.
View Article and Find Full Text PDFPLoS Pathog
January 2025
Chair of Phytopathology, TUM School of Life Sciences, Technical University of Munich, Freising, Germany.
Wheat production is threatened by multiple fungal pathogens, such as the wheat powdery mildew fungus (Blumeria graminis f. sp. tritici, Bgt).
View Article and Find Full Text PDFPlant Dis
January 2025
USDA-ARS SEA, Dale Bumpers National Rice Research Center, Stuttgart, Arkansas, United States;
Major resistance (R) gene mediated resistance to rice blast fungus Magnaporthe oryzae is often overcome by the fungus due to the occurrences of new races with altered corresponding avirulence (AVR) genes. In this study, blast diseased rice tissue samples were collected from breeding stations and commercial rice fields in Arkansas, Louisiana, and Puerto Rico during 2017-2019 to determine the efficacy of major R genes, Pi-ta, Pik, Pizt, Pi9, and Pi33. A total of 185 blast isolates were isolated from the diseased tissue samples to examine the existence of AVR genes AVR-Pita1, AVR-Pib, AVR-Pik, AVR-Pizt, AVR-Pi9 and ACE1.
View Article and Find Full Text PDFJ Fungi (Basel)
December 2024
State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou 510642, China.
Barnyard grass is one of the most serious rice weeds, often growing near paddy fields and therefore potentially serving as a bridging host for the rice blast fungus. In this study, we isolated three fungal strains from diseased barnyard grass leaves in a rice field. Using a pathogenicity assay, we confirmed that they were capable of causing blast symptoms on barnyard grass and rice leaves to various extents.
View Article and Find Full Text PDFCell
December 2024
Chan Zuckerberg Initiative, Redwood City, CA, USA; Department of Bioengineering, Stanford University, Stanford, CA, USA; Department of Applied Physics, Stanford University, Stanford, CA, USA. Electronic address:
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