Rhizoctonia solani Kühn Pathophysiology: Status and Prospects of Sheath Blight Disease Management in Rice

Abstract

Sheath blight caused by necrotrophic fungus Rhizoctonia solani Kühn is one of the most serious diseases of rice. Use of high yielding semi dwarf cultivars with dense planting and high dose of nitrogenous fertilizers accentuates the incidence of sheath blight in rice. Its diverse host range and ability to remain dormant under unfavorable conditions make the pathogen more difficult to manage. As there are no sources of complete resistance, management through chemical control has been the most adopted method for sheath blight management. In this review, we provide an up-to-date comprehensive description of host-pathogen interactions, various control measures such as cultural, chemical, and biological as well as utilizing host plant resistance. The section on utilizing host plant resistance includes identification of resistant sources, mapping QTLs and their validation, identification of candidate gene(s) and their introgression through marker-assisted selection. Advances and prospects of sheath blight management through biotechnological approaches such as overexpression of genes and gene silencing for transgenic development against R. solani are also discussed.

Elevated CO2 and temperature under future climate change increase severity of rice sheath blight

“…Rice ( Oryza sativa L.), one of the most important food crops, serves as the staple food for approximately 67% of the world population ( Senapati et al., 2022 ). Sheath blight (ShB), caused by Rhizoctonia solani Kühn ( Thanatephorus cucumeris (Frank) Donk), is a potentially devastating rice disease in all temperate and tropical rice production regions, especially in irrigated production systems ( Gangopadhyay and Chakrabarti, 1982 ; Lee and Rush, 1983 ; Ou, 1985 ; Dath, 1990 ; Rush and Lee, 1992 ; Rodrigues et al., 2001 ).…”

“…Sheath blight (ShB), caused by Rhizoctonia solani Kühn ( Thanatephorus cucumeris (Frank) Donk), is a potentially devastating rice disease in all temperate and tropical rice production regions, especially in irrigated production systems ( Gangopadhyay and Chakrabarti, 1982 ; Lee and Rush, 1983 ; Ou, 1985 ; Dath, 1990 ; Rush and Lee, 1992 ; Rodrigues et al., 2001 ). The disease was first reported in Japan in 1910 and has subsequently spread to almost all rice-growing area in the world ( Rush and Lee, 1992 ; Senapati et al., 2022 ). Economic losses in rice yields up to 58% have reportedly been demonstrated, due to widespread occurrence ( Chahal et al., 2003 ).…”

“…Meteorological factors, such as air temperature, could directly influence the growth of R. solani in the field ( Castilla et al., 1996 ; Thind et al., 2008 ; Biswas et al., 2011 ; Bhukal et al., 2015 ; Senapati et al., 2022 ). Correlation analysis showed that high air temperature associated with high relative humidity in the forenoon is a major predisposing factor for the development of ShB in rice ( Castilla et al., 1996 ; Biswas et al., 2011 ).…”

“…Correlation analysis showed that high air temperature associated with high relative humidity in the forenoon is a major predisposing factor for the development of ShB in rice ( Castilla et al., 1996 ; Biswas et al., 2011 ). Maximum spread of ShB was observed in a temperature range of 25–30°C and relative humidity of 80–100%, and a maximum temperature around 34°C and a minimum temperature around 26°C were found to be favorable for the dispersal of ShB after its establishment in the field ( Thind et al., 2008 ; Biswas et al., 2011 ; Bhukal et al., 2015 ; Senapati et al., 2022 ). Among the meteorological factors, atmospheric CO 2 concentration and air temperature have been increasing rapidly, and probably the CO 2 level will reach 500–1000 μmol mol -1 and the air temperature will increase by 1.0–3.7°C by the end of this century ( Ciais et al., 2013 ).…”

“…Susceptibility of rice to R. solani can be affected by rice morphological parameters, such as plant height, stem thickness and tiller angle, length and width of flag leaf, days to heading and planting density ( Senapati et al., 2022 ). Some studies found that the susceptibility of rice to R. solani was also related to rice physiological parameters, such as carbohydrate metabolism, phenolic compounds, flavonoids, lignin, membrane lipid peroxidation (MDA) level and POD, PPO and SOD activities ( Ertani et al., 2011 ; Zuo et al., 2014a ; Zuo et al., 2014b ; Molla et al., 2020 ).…”