Frank H. Tainter

Common Multiple dsRNAs Are Present in Populations of the Fungus Discula destructiva Originating from Widely Separated Geographic Locations

DsRNAs were detected in 85/108 isolates of Discula destructiva, the cause of dogwood anthracnose, collected in South Carolina, Idaho, and Alabama. The eastern isolates contained a greater diversity of dsRNA than did Idaho isolates, but most isolates, irrespective of state of origin, contained two small bands (ca. 1.5–2.5 kb) with sequence homology indicated by Northern hybridization. Differences in the banding patterns suggest that genetic diversity of dsRNA in D. destructiva is generated rapidly and that D. destructiva can be simultaneously infected by multiple dsRNA viruses.

Comparative treatability of Moso bamboo and southern pine with CCA preservative using a commercial schedule.

The United States Department of Agriculture introduced several bamboo species into the southern United States in the 1920s. One of the species included was Moso bamboo (Phyllostachys pubescens), a species native to China. This species grows well in South Carolina. In rural areas, bamboo splits are frequently used for fences and stakes for supporting crop plants. However, the decay resistance of bamboo is very low. In this study, Moso bamboo splits and southern pine lumber were treated in a commercial wood-treating plant using a full-cell process with Chromated Copper Arsenate (CCA) preservative to target retentions of 4.0 and 6.4kg/m3. Results indicate that bamboo is much more difficult to treat than southern pine. Using the same treatment procedures for southern pine, bamboo could only achieve approximately 22% of the target CCA retention.

News & Notes: Double-Stranded RNA in Isolates of Discula destructiva from the Pacific Northwestern United States and British Columbia, Canada

Abstract. Twenty-nine isolates of Discula destructiva Redlin from the Pacific northwestern United States and British Columbia, Canada were extracted for the presence of double-stranded RNA by use of phenol-chloroform and CF-11 chromatography. Seven/29 were positive. Agarose-gel banding profiles of the western isolates were different from those found previously in 80/80 isolates from the eastern U.S. These results suggest that isolates of D. destructiva responsible for dogwood anthracnose in Washington, Oregon, Idaho, and British Columbia may have an origin different from that of the eastern isolates.

Double-stranded RNA in isolates ofDiscula destructiva from the Eastern United States

Phenol-chloroform extraction and CF-11 chromatography were used to examine 83 isolates ofDiscula sp. for the presence of dsRNA. Agarose-gel electrophoresis revealed three major size classes: large (ca. 8–12 kbp), medium (ca. 3–4 kpb), and small (ca. 1.5–2.5 kbp). Additional segments were present in two isolates. Double-stranded RNA was demonstrated in 80/80 isolates ofDiscula destructiva, but not in three isolates of an unidentifiedDiscula sp. commonly referred to asDiscula, Type 2. Twenty-two isolates contained one or more large segments. Isolates with large segments were more common in collection sites on the eastern slope of the Appalachian Mountains. The most common banding profile consisted of two medium and two small bands.

A sporulation medium forDiscula destructiva, the dogwood anthracnose fungus

A growth medium incorporating finely ground oak or maple leaf tissue was developed for the purpose of increasing in vitro conidium production by the dogwood anthracnose pathogen,Discula destructiva.

Genetic relatedness among dsRNAs from different isolates ofDiscula destructiva

The genetic relationships among double-stranded RNAs (dsRNAs) from 76 isolates ofDiscula destructiva obtained from different geographic locations from New York to Alabama were studied by dot-blot hybridization. The dsRNA segments, identified by agarose gel electrophoresis, varied in size and number. Probes were constructed from total dsRNA from six isolates with different dsRNA profiles and of different geographic origins. Each probe hybridized with dsRNA from ca. 62% of the isolates under the high-stringency washing conditions used. No major differences in the percentage of the total isolates that hybridized with each probe were observed. These results suggest a recent common origin of these isolates ofD. destructiva.

A membrane technique for producing protoplasts ofCryphonectria parasitica

A method for the formation and regeneration of protoplasts of several strains of the chestnut blight fungus,Cryphonectria parasitica, is presented. The procedure utillizes cellophane membranes for growth and employs centrifugation for separation of protoplasts from hyphal fragments. Yields averaged 8.04×106 protoplasts per membrane. Regeneration frequencies were 40–50% with a soft-agar overlay. These protoplasts are suitable for use in experiments designed to determine the role of dsRNA in hypovirulence ofC. parasitica.

Bacteria associated with butterfly stain of Chilean tepa.

Abstract. Butterfly stain, common in Chilean tepa (Laureliopsis philippiana[Looser] Schodde) trees, appears in cross-section of the stem as a series of partially overlapping orange-brown arcs that in early stages resembles a butterfly. Bacterial isolates from stained tepa wood samples cultured under aerobic and anaerobic conditions were identified using several commercially available identification systems. Pseudomonas sp. were most common in the cultures handled aerobically, and Clostridium sp. were found in the cultures handled anaerobically. A pectinolytic Bacillus sp. and a Gram-negative rod-shaped bacterium that emitted a strong naphthalene-like odor similar to that of stained wood were also isolated. Not all isolates could be identified. This is the first report of Clostridium from tepa.