Spontaneous Mutations at Fingerprint Loci in Clonal Lineages of the Rice Blast Fungus

Wu, B.C., and Magill, C. W. 1995. Spontaneous mutations at fingerprint loci in clonal lineages of the rice blast fungus. Experimental Mycology 19, 86-90. When successive asexual generations of monospore-derived cultures from the Tm5 strain of Magnaporthe grisea were subjected to DNA fingerprint analysis with an anonymous genomic DNA probe, gain or loss of hybridizing fragments was common. Three of 24 isolates examined in the first asexual generation gained a BamHl fragment. In the next generation six cultures derived from two of these isolates all gained or lost up to three fragments. By comparison, only 1 of 28 isolates from a different culture showed a fingerprint band change, which was the loss of one fragment in the second generation. Where tested, changes in one isolate were also present in its progeny, and since 28 fragments could be scored in the original cultures, the overall patterns remained distinct. However, at the rate of change seen in the Tm5 isolates, fingerprint patterns have the potential to diverge rapidly.