Link to home

Genetic Mapping and Chromosomal Assignment of Magnaporthe oryzae Avirulence Genes AvrPik, AvrPiz, and AvrPiz-t Controlling Cultivar Specificity on Rice

June 2005 , Volume 95 , Number  6
Pages  640 - 647

Chao-Xi Luo , Liang-Fen Yin , Satomi Koyanagi , Mark L. Farman , Motoaki Kusaba , and Hiroshi Yaegashi

First, second, third, fifth, and sixth authors: Faculty of Agriculture, Saga University, Saga, 840-8502, Japan; and fourth author: Department of Plant Pathology, University of Kentucky, Lexington 40546

Go to article:
Accepted for publication 9 February 2005.

A genetic map including three avirulence (Avr) genes, AvrPik, AvrPiz, and AvrPiz-t, was constructed in a genetic cross of two rice field isolates, 84R-62B and Y93-245c-2. The chromosomal locations of the Avr genes were determined by using selected markers to probe Southern blots of the parental chromosomes that had been separated by contour-clamped homogenous electric fields electrophoresis. Electrophoretic karyotyping showed that both parental isolates 84R-62B and Y93-245c-2 contained seven chromosomes greater than 3.5 megabases (Mb) in size and 84R-62B possessed a small chromosome of ≈1.6 Mb. The linkage groups containing AvrPiz and AvrPiz-t were assigned to chromosomes 3 and 7, respectively. Some markers from the linkage group that contained AvrPik hybridized with chromosome 1 and the 1.6-Mb chromosome, yet all of the cloned RAPD markers that were closely linked to AvrPik hybridized exclusively to the 1.6-Mb chromosome in 84R-62B, the parent that possesses AvrPik. Thus, we conclude that AvrPik is located on the 1.6-Mb chromosome in 84R-62B.

Additional keywords: Pyricularia grisea , P. oryzae , rice blast fungus .

© 2005 The American Phytopathological Society