An In Planta Method for Assessing the Role of Basidiospores in Rhizoctonia Foliar Disease of Tomato

Abstract

A tomato (Solanum lycopersicum) foliar blight disease of unknown etiology was observed in North Carolina (NC) during 2005 to 2006. Symptoms included necrotic lesions and blighted leaves, with signs of white mycelial growth on abaxial leaf surfaces. The morphology of isolates from symptomatic leaves was consistent with that of Rhizoctonia solani. Because the pattern of symptom expression suggested that basidiospores were the primary inoculum source, Koch's postulates were fulfilled using a method to generate basidiospores in planta. Isolates were characterized by morphology, DNA sequence analysis, hyphal anastomosis, and somatic hyphal interactions. Phylogenetic analyses and hyphal anastomosis criteria support placement of the isolates in R. solani anastomosis group 3 (AG-3). Tomato foliar blight isolates from NC form a single phylogenetic group with tomato isolates of R. solani AG-3 from Japan and are more closely related to R. solani AG-3 isolates from potato than tobacco. Isolates exhibited both compatible and incompatible hyphal interactions when paired in vitro. To our knowledge, this is the first detailed report of tomato foliar blight caused by R. solani AG-3 in North America. A comprehensive description of the technique employed for producing basidiospores is presented with potential utility for understanding foliar disease etiology in other Rhizoctonia pathosystems.

Assessment of the impact of the fumigant dimethyl disulfide on the dynamics of major fungal plant pathogens in greenhouse soils

“…1b). R. solani is considered a fungal complex composed of 13 anastomosis groups (AG) with strains belonging to the AG3, as the dominant strain in our soil, being tomato pathogens (Bartz et al 2010).…”

Vascular Streak Dieback of cacao in Southeast Asia and Melanesia: in planta detection of the pathogen and a new taxonomy

“…Attempts to stain nuclei of Ot using phenosafranine (Bartz et al 2010), aniline blue, and trypan blue (Sneh et al 1991) were not successful. Nuclei in hyphae of a second Rhizoctonia-like fungus that was isolated from cacao tissue and grew rapidly in culture, described below, were stained with phenosafranin (SigmaeAldrich199648-1G, 0.1 % aq.)…”

Relative Contribution of Seed Tuber- and Soilborne Inoculum to Potato Disease Development and Changes in the Population Genetic Structure of Rhizoctonia solani AG 3-PT under Field Conditions in South Africa

“…Their role as an inoculum source in Rhizoctonia disease epidemics on potato has not been demonstrated (Jeger et al 1996). In other crops, such as tobacco and tomato, basidiospores have been reported to serve as primary or secondary inoculum in addition to seed tuber-borne and soil-borne inocula (Bartz et al 2010;Shew and Melton 1995). Several studies have provided compelling evidence that basidiospores play an important role in shaping the population genetic structure of R. solani AG 3-PT on potato (Ceresini et al 2002;Ferrucho et al 2013).…”