Cytomolecular aspects of rice sheath blight caused by Rhizoctonia solani

Abstract

Sheath blight, caused by anastomosis group 1-IA of Rhizoctonia solani Kühn (teleomorph Thanatephorus cucumeris (Frank) Donk), is one of the most destructive rice diseases worldwide. The pathogen is able to infect plants belonging to more than 27 families, including many economically important monocots and dicots such as rice, wheat, alfalfa, bean, peanut, soybean, cucumber, papaya, corn, potato, tomato and sugar beet. It is a soil borne necrotrophic fungus that survives in plant debris as sclerotia, which are small brown-to-black, rocklike reproductive structures. The sclerotia can survive in the soil for several years and infect rice plants at the water-plant interface in the flooded field by producing mycelia. Management of rice sheath blight requires an integrated approach based on the knowledge of each stage of the disease and cytomolecular aspects of rice defence responses against R. solani. This review summarizes current knowledge on molecular aspects of R. solani pathogenicity, genetic structure of the pathogen populations, and the rice-R. solani interaction with emphasis on cellular and molecular defence components such as signal transduction pathways, various plant hormones, host defence genes and production of defence-related proteins involved in basal and induced resistance in rice against sheath blight disease.

Comparison among four triazole fungicides on growth and development of sheath blight of rice pathogenRhizoctonia solaniKühn AG1-1A

“…An important part of the study was to compare hexaconazole, difenoconazole, tebuconazole and propiconazole in their ability to suppress sclerotial formation of R. solani. Sclerotia are important vegetative structures formed by R. solani to survive from one cropping season to the other and often are the primary mode of disease infection (Taheri & Tarighi 2011;Yu et al 2012). The results showed significant (p ≤ 0.05) suppression of sclerotia under fungicide treatment in comparison to control (Table 3).…”

“…It is composed of compact hyphal mass that can survive in the soil and crop debris from one season to another. They are capable of floating in irrigation water and in most cases forms the primary inoculum for the disease (Taheri & Tarighi 2011;Yu et al 2012). Cell wall degrading enzymes (CWDE) of a pathogen plays an important role during infection process (Reignault et al 2000).…”

The Role of Pathogenesis-Related Proteins in the Tomato-Rhizoctonia solani Interaction

“…Thus, our results contribute to the understanding of basal resistance in the important tomato-R. solani pathosystem. Disease management strategies rely on our knowledge concerning cellular and molecular aspects of the tomato-R. solani interaction, defense mechanisms and signal transduction pathways involved in resistance against the pathogen [14]. Therefore, our knowledge about defense responses involved in basal resistance of tomato could be useful in breeding programs leading to obtain cultivars with higher levels of resistance.…”

“…The PR-9 group contains a specific type of peroxidase that could act in cell wall reinforcement by catalyzing lignification [14] and enhance resistance against multiple pathogens with different life styles. It has been suggested that peroxidases are involved in the resistance of heated tomato fruits to infection with Botrytis cinerea as a destructive necrotrophic phytopathogen [15].…”

Comparison of gene co-networks reveals the molecular mechanisms of the rice (Oryza sativa L.) response to Rhizoctonia solani AG1 IA infection

“…Accompanying cultivars that are susceptible to sheath blight are planted in most rice-growing regions of the world, which increases yield losses from this disease. Although rice varieties that are relatively resistant to sheath blight have been identified (Prasad and Eizenga 2008), no completely field resistant rice cultivar or immune variety has been found (Zeng et al 2015; Taheri and Tarighi 2011). At present, management of this disease mainly involves chemical methods.…”