Ha. Yang et al., GENETIC-VARIABILITY IN PECTIC ENZYMES OF RHIZOCTONIA-SOLANI ISOLATES CAUSING BARE-PATCH DISEASE OF CEREALS, Journal of phytopathology, 141(3), 1994, pp. 259-266
Field isolates of Rhizoctonia solani obtained from three discrete bare
patches in a wheat field in Western Australia were characterized by p
ectic zymogram grouping. The genetic background of pectic enzymes was
analysed by comparing the zymograms of asexual homokaryons and sexual
progenies derived from field isolates. The 170 field isolates obtained
from the field site produced indistinguishable pectic zymograms. Howe
ver, variations among field isolates of the same zymogram group were d
etected on the basis of zymograms of their resultant protoplast-regene
rated cultures. Asexual sibling homokaryons derived from each of the f
ield isolates were heterogeneous for their pectic enzymes. Homokaryons
with a common heterokaryon incompatibility factor obtained from a fie
ld isolate were homogeneous for pectic enzymes. Basidiospore progenies
of a field isolate segregated widely in pectic zymograms. It appeared
that the expression of pectic enzymes by field isolates involved mult
iple genetic factors. The variation of zymograms among homokaryotic st
rains suggests that each field isolate of R. solani contains two types
of nuclei, although cells of vegetative hyphae are multinucleate.