Abstract
The development of new races of the rice blast pathogen continues to circumvent the best efforts of plant breeders to develop blast resistant cultivars. Sampling field populations of the rice blast fungus from 1990-1997 has indicated that four MGR586 DNA fingerprint groups (A, B, C, and D) occur in the contemporary rice blast pathogen population in Arkansas. All field isolates examined in fingerprint groups A and C had an IB-49 virulence phenotype whereas most isolates in fingerprint groups B and D had an IC-17 virulence phenotype. However, several field isolates in fingerprint group B had an IG-1 or an IC-lk virulence phenotype; race IC-lk was virulent on the more recently released resistant cultivar Katy. Because race diversity was greater within the B fingerprint group based on evidence from the field isolates, it was hypothesized that spontaneous mutations affecting host specificity could occur more readily among isolates in fingerprint group B. Five representative isolates, one each from DNA fingerprint groups A, C, and D, and two isolates (an IG1 and an IC-17 isolate) in fingerprint group B were inoculated on the cultivars M201, Newbonnet, and Katy. A marked strain (a sulfate nonutilizing mutant) of each isolate was used, along with DNA fingerprints, to rule out any possibility of cross-contamination during the inoculation tests. A single-spored isolate was recovered from 15–20 rare lesions observed on the resistant cultivar Katy after inoculation with all five isolates. None of the single-spore isolates recovered from the A or C isolate inoculations were virulent when re-inoculated onto Katy whereas 2 of 20 single-spored isolates from the D isolate inoculation were virulent when re-inoculated onto Katy. However, 13 of 16 single-spored isolates recovered from the B isolate (race IG1) inoculation and 17 of 19 single spored isolates recovered from the B isolate (race IC17) inoculation were virulent when re-inoculated onto Katy. The data indicate that spontaneous mutation to virulence on Katy occurred at a much higher frequency in the two isolates in the B fingerprint group than the isolates in fingerprint groups A, C, or D. Inoculations with additional isolates in all four fingerprint groups indicated that the frequency of the spontaneous host-specificity mutation was consistently higher among some, but not all isolates, in the B fingerprint group. Although circumstantial, the data indicate that virulent phenotypes capable of infecting Newbonnet and Katy originated from the resident population.
This is a preview of subscription content, log in via an institution to check access.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
References
Bonman,.I. M, Vergel de Dios, T. I., Bandong, J. M., and Lee, E. J. 1986. Pathogenic variability of monoconidial isolates of Pyricularia oryzae in Korea and in the Philippines. Plant Dis. 71, 127 - 130.
Correll, J.C., Guerber, J.C., and Lee, F.N. 1995. Virulence instability of an MGR-DNA fingerprint group of the rice blast pathogen. Mycol. Soc. Newsletter 46, 9.
Correll, J.C., Guerber, J.C., and Lee, F.N. 1995. Examination of virulence among isolates in MGR586 DNA fingerprint groups of the rice blast pathogen, Pyricularia grisea, in Arkansas. Phytopathology 85, 1199.
Correll,.I.C., Harp, T. L., Lee, F. N., and Zeigler, R. S. 1998. The use of vegetative compatibility to examine population structure in Pyricularia grisea. Phytopathology 88, S19.
Giatgong, P, and Frederiksen, R. A. 1969. Pathogenic variability and cytology of monoconidial subcultures of Pyricularia ory:oe. Phytopathology 59, 1152 - 1157.
Hamer, J.E., Farrall, L., Orbach, M.J., Valent, B., and Chumley, F.G. 1989. Host species-specific conservation of a family of repeated DNA sequences in the genome of a fungal plant pathogen. Proc. Natl. Acad. Sci. USA 86, 9981-9985.
Harp, T.L., and Correll, .I.C. 1998. Recovery and characterization of spontaneous, sclenate-resistant mutants of Magnaporthe grisea,the rice blast pathogen. Mycologia 90, (in press)
Kang, S. Sweigard, J. A., and Valent, B. 1995. The PWL host specificity gene family in the blast fungus, Magnaporthe grisea. Mol. Plant-Microbe Interact. 8, 939-948.
Lee, F.N. 1994. Rice breeding programs, blast epidemics and blast management in the United States. Rice Blast Disease 489-500 pp. Zeigler, R.S., Leong, S., and Teng, P.S. eds. Commonwealth Agricultural Bureaux International, Willingford, UK.
Long, D. H., TeBeest, D. O., and Correll, J. C. 1998. The effect of plant age on the spatial and temporal dynamics of rice blast in Arkansas. (this volume).
Marchetti, M.A. 1994. Race-specific and rate-reducing resistance to rice blast in U. S. cultivars. In Rice Blast Disease 231-244 pp. Zeigler, R.S., Leong, S., and Teng, P.S. eds. Commonwealth Agricultural Bureaux International, Willingford, UK.
Ou, S.H. 1980. Pathogen variability and host resistance in rice blast disease. Annu. Rev. Phytopathol. 18, 167-187.
Ou, S. H., and Ayad, M. R. 1968. Pathogenic races of Pyricularia oryzae originating from single lesions and monoconidial cultures. Phytopathology 58, 179 - 182.
Shull, V., and Hamer, J.E. 1994. Genomic structure and variability in Pyricularia grisea. In Rice Blast Disease 65-86 pp. Zeigler, R.S., Leong, S.A., and Teng, P.S. eds. Commonwealth Agricultural Bureaux International, Willingford, U.K.
Valent, B. and Chumley, F.G. 1994. Avirulence genes and mechanism of genetic instability in the rice blast fungus. Rice Blast Disease 111-134 pp. Zeigler, R. S., Leong, S., and Teng, P.S. eds. Commonwealth Agricultural Bureaux International, Willingford, UK.
Xia, J. Q., Correll,.1. C., Lee, F. N., Rhoads, D. D., and Marchetti, M. A. 1993. DNA fingerprinting to examine variation in the Magnaporthe grisea (Pyricularia grisea) population in two rice fields in Arkansas. Phytopathology 83, 1029 - 1035.
Zeigler, R. S. 1998. Recombination in Magnaporthe grisea. Ann. Rev. Phytopath. 36, 249-275.
Zeigler, R.S., Scott, R. P., Leung, H., Bordeos, A. A., Kumar, J., and Nelson, R.J. 1997. Evidence of parasexual exchange of DNA in the rice blast fungus challenges its exclusive clonality. Phytopathology 87, 284 - 294.
Author information
Authors and Affiliations
Editor information
Rights and permissions
Copyright information
© 2000 Springer Science+Business Media Dordrecht
About this paper
Cite this paper
Correll, J.C., Harp, T.L., Guerber, J.C., Lee, F.N. (2000). Differential Changes in Host Specificity among MGR586 DNA Fingerprint Groups of Pyricularia Grisea . In: Tharreau, D., Lebrun, M.H., Talbot, N.J., Notteghem, J.L. (eds) Advances in Rice Blast Research. Developments in Plant Pathology, vol 15. Springer, Dordrecht. https://doi.org/10.1007/978-94-015-9430-1_28
Download citation
DOI: https://doi.org/10.1007/978-94-015-9430-1_28
Publisher Name: Springer, Dordrecht
Print ISBN: 978-90-481-5436-4
Online ISBN: 978-94-015-9430-1
eBook Packages: Springer Book Archive