The distribution of a previously described repeated DNA sequence present as a 1.3-kb PstI fragment in the genome of the rice blast fungus Magnaporthe grisea was analysed by carrying out DNA fingerprint analysis of 36 isolates including rice, non-rice and laboratory strains. The analysis of various higher-molecular-weight PstI fragments with homology to the 1.3-kb repeat revealed that these may arise predominantly from transposon insertions or point mutations. Analysis of a 5.1-kb derivative revealed both a point mutation at a PstI site and an insertion of a putative transposable element which caused an increase in molecular weight from 1.3 to 5.1 kb. Another repeat element of 1.4 kb was identified and found to exist in association with the 1.3-kb repeat. Both 1.3- and 1.4-kb elements were found to be parts of MGR583, a LINE-like element. These elements were present in a high copy number in all the rice and a majority of non-rice pathogens indicating that MGR583 is not a host-specific sequence as reported earlier. Our results suggest that repeated DNA elements in M. grisea have amplified independently of one another and further indicate that different isolates of M. grisea may have evolved from several distinct lines of origin.
|Number of pages||9|
|State||Published - Apr 1997|
Bibliographical noteFunding Information:
Acknowledgements We thank Drs. Naoto Nitta, (Department of Plant Pathology, University of Wisconsin, Madison, USA) for providing the DNA samples of progeny obtained from a cross between Guy11 and 2539, and Mark Farman (Department of Plant Pathology, University of Wisconsin, Madison, USA) for providing the DNA samples of some of the non-rice pathogens, for the Pot3 clone and also for sharing his unpublished data. Finally, we thank Dr. Autar Mattoo (USDA, Beltsville, M.D., USA) for his critical reading of the manuscript. This work was supported by grants from the Department of Biotechnology, Government of India, and by the Rockefeller Foundation to B.B.C., as well as by the United States Department of Agriculture and the Rockefeller Foundation to S.A.L.
Copyright 2007 Elsevier B.V., All rights reserved.
- Repeated DNA
- Rice blast
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