DNA sequence data and morphology defineCryphonectriaspecies in Europe, China, and Japan

Abstract

Cryphonectria includes important tree pathogens as well as species believed to be saprophytes. Recent phylogenetic studies have concentrated on North American and southern hemisphere Cryphonectria spp., but little is known about Asian and European taxa. In this study we identify and differentiate among the species occurring in Europe, China, and Japan using morphological and phylogenetic comparisons among the Cryphonectria species. Phylogenetic comparisons were based on sequence data from the ribosomal ITS operon and two regions in the β-tubulin gene. Unknown Japanese and Chinese isolates showing different cultural features than those of Cryphonectria parasitica (Murrill) M.E. Barr from Japan and the USA, grouped with isolates of Cryphonectria nitschkei (G.H. Otth) M.E. Barr from Quercus spp. and Rhus javanica L. Isolates of Cryphonectria havanensis (Bruner) M.E. Barr from Quercus grosseserrata Blume, Castanopsis cuspidata Schottky, Pyrus sinensis Lindl., and Eucalyptus globulus Labill. also grouped in this phylogenetic clade. We propose that Cryphonectria nitschkei and the fungus that has been referred to as Cryphonectria havanensis in Japan should be treated as a single taxon. Phylogenetic and morphological data also suggest that there are two species currently representing Cryphonectria radicalis (Schwein.: Fr.) M.E. Barr in Europe. One of these species is similar to the type specimen of Cryphonectria radicalis, while the other species probably is new.Key words: Cryphonectria parasitica, Cryphonectria radicalis, Cryphonectria havanensis, Cryphonectria macrospora, Cryphonectria nitschkei, Diaporthales.

Cytological and electrophoretic karyotyping of the chestnut blight fungus Cryphonectria parasitica

“…These probes were chosen because they exist as a single copy (nam-1 and b-tubulin gene) or a cluster (ITS) in the genome of C. parasitica and hence can serve to identify specific chromosomes. All probes were prepared by PCR using the total DNA of EP155 as template and primer sets for the respective genes: Nam-7 (5 0 -GCATAGT GAATGGAGCCG-3 0 ) and Nam-49 (5 0 -CAGCCCTGAGTACTTCTCC-3 0 ) for nam-1 (Faruk et al, 2008a), beta-tub7 N (5 0 -GAG GACCA GATGCGCAAC-3 0 ) and beta-tub7C (5 0 -GTGTACCAATGCAA GAAAGCC-3 0 ) for b-tubulin gene (Myburg et al, 2004), and ITS4 (5 0 -TCCTCCGCTTATTGATATGC-3 0 ) and ITS5 (5 0 -GGAAGTAAAAG TCGTAACAAGG-3 0 ) for rDNA (White et al, 1990). Probe labeling, hybridization, and detection of signals were carried out with the PCR DIG synthesis kit (Roche) for all the probes.…”

A review of the phylogeny and biology of the Diaporthales

“…& M.J. Wingf. and several related species threaten eucalyptus trees throughout the world (Gryzenhout et al , 2005d (Hoegger et al 2002;Myburg et al 2004) and are often observed in their Endothiella pycnidial states on the exposed roots of hardwood trees.…”

Molecular diversity of chrysoviruses in Korean isolates of a new fungal species, Cryphonectria nitschkei

“…(Lee et al, 1992), although no further studies have been conducted. Firm identification of these Cryphonectria species based on morphology is challenging because the range of spore sizes commonly overlaps and the ascospores are not always fully developed, resulting in variable measurements (Myburg et al, 2004a). In addition, without complete information on the effects of chrysovirus infection on fungal morphology, conclusively identifying abnormal strains of Cryphonectria species based on morphology is even harder.…”

“…Even though major species of Cryphonectria, such as C. parasitica, C. nitschkei, C. macrospora, and C. radicalis, are known to occur on woody hosts in East Asia (Myburg et al, 2004b), morphological taxonomic identification is still extremely challenging. Therefore, molecular taxonomic studies based on DNA sequence comparisons have been used to resolve many questions (Myburg et al, 2004a).…”

“…Sequence comparisons based on the ITS of the nuclear ribosomal RNA subunit were conducted to confirm that the dsRNA-containing strains were C. parasitica, as previously described (Myburg et al, 1999(Myburg et al, , 2004aLiu et al, 2003). The ITS-1, 5.8S, and ITS-2 regions were amplified via the polymerase chain reaction (PCR) using the ITS1 and ITS4 primers (White et al, 1990).…”