T. Hsiang et Cr. Wu, Genetic relationships of pathogenic Typhula species assessed by RAPD, ITS-RFLP and ITS sequencing, MYCOL RES, 104, 2000, pp. 16-22
Several species of Typhula cause diseases of cereals and grasses at low tem
peratures. Taxonomic separation of T. phacorrhiza, T. incarnata and T. ishi
kariensis was investigated using RAPD, ITS-RFLP and nucleotide sequencing o
f the TTS region. Using 10 RAPD primers on genomic DNA or eight restriction
enzymes on PCR-amplified ITS regions, banding patterns were generated for
each of 19 isolates from five species or varieties. Polymorphisms were foun
d between species and varieties, with fewer among isolates within species o
r varieties. RAPD analysis suggested that T. ishikariensis var. idahoensis
may be distinct from the other varieties (var. ishikariensis and var. canad
ensis), although this was not supported by ITS-RFLP. To confirm relationshi
ps, ITS nucleotides were obtained from single isolates of each of the five
Typhula taxa, and sequence alignments were subjected to distance and parsim
ony analysis. Although there were differences in branching between dendrogr
ams derived from sequencing vs. RAPD or ITS-RFLP, sequence data supported t
he distinction of the three main Typhula species, with the T. ishikariensis
Varieties grouping together and showing differences at an infraspecific le
vel. ITS sequence data also indicated the closer taxonomic affinity of Typh
ula species to the agaricoid Tricholoma sejunctum compared to the clavarioi
d Thelephora terrestris.