Mg. Milgroom et Se. Lipari, MATERNAL INHERITANCE AND DIVERSITY OF MITOCHONDRIAL-DNA IN THE CHESTNUT BLIGHT FUNGUS, CRYPHONECTRIA-PARASITICA, Phytopathology, 83(5), 1993, pp. 563-567
The inheritance of mitochondrial DNA (mtDNA) in the chestnut blight fu
ngus, Cryphonectriaparasitica, was investigated with laboratory crosse
s and progeny from perithecia collected from a natural population. In
a reciprocal cross, mtDNA haplotypes, determined from restriction frag
ment length polymorphisms (RFLPs), were inherited only from maternal p
arents. Another lab cross, in which the maternal strain was not known,
showed uniparental inheritance for 43 ascospore progeny. All 87 proge
ny from eight perithecia collected in the field showed uniparental inh
eritance of mtDNA haplotypes identical to the maternal (canker) isolat
es. These data strongly support the hypothesis that mtDNA is maternall
y inherited in C. parasitica. In samples from three populations of C.
parasitica, mtDNA haplotypes were highly diverse. Estimates of haploty
pic diversity were high, ranging from 0.832 to 0.968 (maximum diversit
y is 1.0 when all individuals have unique haplotypes). The possible ca
uses of hypervariability in mtDNA are discussed.