© 2019 PP House Efcacy of Biotc and Chemical Inducers of SAR in Management of Plant Viruses Himashree Duta, R. Gowtham Kumar and Munmi Borah * Plant Virology Laboratory, Department of Plant Pathology, Assam Agricultural University, Jorhat, Assam (785 013), India The objectve of this study was to review the published research works on management of viral diseases of crop plants in recent years using microbial antagonists and chemical inducers of SAR. Systemic acquired resistance (SAR) and induced systemic resistance (ISR) are two forms of induced resistance; in both SAR and ISR, plant defenses are preconditoned by prior infecton or treatment that results in resistance (or tolerance) against subsequent challenge by a pathogen or parasite. Much of this knowledge is due to the identfcaton of a number of chemical and biological elicitors, some of which are commercially available for use in conventonal agriculture. The biocontrol potental of Bacillus spp. and Pseudomonas spp in relaton with their antagonizing atributes against plant viruses revealed their efcacy against Tobacco Mosaic Virus (TMV), Coton leaf curl virus (CLCuV), Cucumber mosaic virus (CMV) and some other plant viruses are discussed in this review. Recent researches on mechanisms of biological control by PGPR revealed that several plant growth promotng rhizobacteria (PGPR) strains protect plants against viral infecton through inducton of systemic resistance. Studies were done to evaluate specifc strains of PGPR for induced resistance in indicator plants like Chenopodium and Arabidopsis thaliana. The classic form of SAR can be triggered by exposing plant to virulent, avirulent, and nonpathogenic microbes viz. microbial antagonist, or artfcially with chemicals such as salicylic acid 2,6-dichloro-isonicotnic acid (INA) or benzo (1, 2, 3) thiadiazole-7-carbothioic acid S-methyl ester (BTH) etc. which are considered as chemical inducers of SAR. Progress with efcient use of diferent biological agents against plant viruses is a worthwhile approach in context of sustainable crop health management. 1. Introducton Plant infection by viruses causes physiological disorders responsible for plant diseases of economic and agronomic signifcance in many crops. Plant viruses cause epidemics on all major cultures of agronomic importance, representng a serious threat to global food security. As strict intracellular pathogens, they cannot be controlled chemically and prophylactc measures consist mainly in the destructon of infected plants and excessive pestcide applicatons to limit the populaton of vector organisms. The years of dependence and extensive use of the agrochemicals have led to undesirable effects on the environment, on non-target organisms and development of carcinogenicity in humans (Heydari, 2007). Taking into account the requirement of alternatve approaches, biological control seems efectve and benefcial. In simple terms, biological control involves the control of one organism using another organism or products derived from another organism (Cook, 1993). The inducton of plant resistance using microbial antagonist or other abiotc elicitors is also a form of biological control (Schouten et al., 2004). It is widely known that plants can defend themselves against pathogen infecton through a variety of mechanisms that can be either local, consttutve, or inducible (Franceschi et al., 1998; 2000). Inducible resistance mechanisms such as systemic acquired resistance (SAR) are broad spectrum plant defense responses that can be induced biologically by challenging a plant with a weaker strain of a specifc pathogen or exposing a plant to natural and/or synthetc chemical compounds (Elliston et al., 1977). SAR has been studied by plant biologists for the past 100 years as a means to increase resistance to fungal, bacterial, and viral pathogens in crop plants such as potato, wheat, and rice (Agrios, 1997). In this review, diferent aspects of biological control of viral plant diseases including inducton of resistance using diferent microbial antagonists and chemical SAR activators, the mechanisms involved and their methods of applicaton in diferent crops have been covered. 2. Biotic and Chemical Inducers of Systemic Acquired Resistance against Plant Viruses Plants develop a generalized resistance in response to infecton Elicitors, induced resistance, plant defense Keywords: Abstract Article History Artcle ID: IJEP0323 Received in 03 rd August, 2019 Received in revised form 17 th August, 2019 Accepted in fnal form 25 th August, 2019 Munmi Borah e-mail: mborah56@gmail.com Corresponding Author Review Article Doi: HTTPS://DOI.ORG/10.23910/IJEP/2019.6.3.0323 130 International Journal of Economic Plants 2019, 6(3):130-135