••• Annual Reports

FIRST ANNUAL REPORT


SECOND ANNUAL REPORT


THIRD ANNUAL REPORT


FOURTH PROGRESS REPORT


Specific objectives for the first year :

1 Positional cloning of avirulence genes
2. Analysis of the diversity at avirulence loci in the Chinese Rice Blast Fungus populations
3. Segregation analysis of the putative RGBs in different populations
4. Identification of the gene loci with the combination defined previously
5. Identification of molecular markers closely linked to the mapped RGBs.


Results and Milestones :

Based on previous mapping results of an avirulence gene a physical map was established. Complementation assays had failed for technical reasons. We modified our procedures and made sure that the technique is operating. One hundred and one transformants corresponding to 15 different BAC clones were tested. None of them complemented the virulent phenotype. So, despite our efforts, we could not clone the avirulence gene.
Survey of alleles of the avirulence gene ACE1 in the Chinese population of the rice blast fungus was completed. One hundred thirty additional isolates were characterized by PCR. On the total 216 isolates characterized from the beginning of the project, 166 (76.9 %) amplified the avirulence allele (Guy11 allele), 9 (4.2 %) did not amplify any fragment (null allele), and 14 (6.5 %) and 27 (12.5 %) amplified the virulence alleles CM28 and PH14 respectively. Pathogenicity on varieties carrying the Pi33 gene (the resistance gene corresponding to ACE1) were realized for a subset of 56 isolates. Unambiguous phenotype was determined for 51 of them. The only null allele isolate tested was avirulent. All the 19 isolates bearing the PH14 virulence allele were virulent. Three and 5 isolates carrying the virulence allele CM28 were virulent and avirulent respectively. Three and 20 isolates bearing the Guy11 allele were virulent and avirulent respectively.
A total of 12 additional screens of the Bala x Azucena mapping population where conducted, involving 11 of the 18 target Blast isolates. An additional marker was added to the map of this cross to improve the identification of QTLs. The study of one QTL of interest from the cross ZYQ8 x JX17 was started. DH lines carrying the QTL were chosen and backcrossed with the susceptible parent to develop new mapping population. Further fine mapping of the QTL was conducted too by using AFLP markers. This work is still under progress.


Future Actions :

This project is now over. All partners will go on the research activities developed in the Residiv project after the end of the project. Partners also want to set up new projects to exploit the results of the Residiv project and to go on collaborating research.