Vol. 12, Issue 9 (2023)

Author(s):
NK Singh, DP Singh and N Raghubanshi

Abstract:
Rice sheath blight, caused by the fungal pathogen Rhizoctonia solani Kuhn (sexual stage: Thanetophorus cucumeris (Frank) Donk), is a major problem in rice-producing countries worldwide. When conditions are favorable, it can lead to a significant loss of up to 50% in grain yield. While fungicides can be used for control, their cost and the potential for pathogen resistance make plant genetic resistance a more desirable approach. Through various biotic or abiotic stresses, plants can be locally and systemically induced to enhance their resistance against diseases. Systemically induced resistance, known as SAR (systemic acquired resistance), is a sign pathway that is highly effective in providing protection against a wide range of pathogens. It is triggered by localized infections caused by necrotizing pathogens. SAR is characterized by the activation of specific proteins and its reliance on salicylic acid (SA). Several chemical compounds have been identified that can influence different stages of these defense activation networks, mimicking the natural process of resistance. These compounds offer farmers an additional tool to enhance disease resistance, complementing genetic resistance and the use of fungicides. When incorporated effectively into plant fitness management packages, they have the potential to extend the useful lifespan of both resistance genes and the currently employed fungicides. Thifluzamide belongs to the carboxamide group of fungicides, specifically functioning as a single-site inhibitor of the succinate ubiquinone reductase or succinate dehydrogenase (Sdh) complex in the respiratory chain. By inhibiting succinate dehydrogenase in the tricarboxylic acid cycle, these fungicides disrupt fungal respiration. This information aims to provide knowledgeable readers with an informative overview of the role and potential benefits of including such strategies in plant fitness management. (O’Reilly 1995). Rice sheath blight, which is primarily caused by Rhizoctonia solani Kühn (also known as Thanatephorus cucumeris (A.B. Frank) Donk), poses a significant challenge to rice cultivation, second only to rice blast. This fungal disease, prevalent in lowland tropical regions of Asia, leads to yield losses ranging from 5% to 10%. (Willocquet et al., 2004). The pathogen demonstrates a broad spectrum of hosts, capable of infecting over 32 plant families and 188 genera, often affecting legume crops that are commonly rotated with rice. Thifluzamide has been identified as an effective solution for managing rice sheath blight, making it suitable for integration into resistance management strategies by incorporating it into spray schedules in potential rice-growing regions.