Efficacy of Biotic and Chemical Inducers of SAR in Management of Plant Viruses

Abstract

The objective 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 preconditioned by prior infection or treatment that results in resistance (or tolerance) against subsequent challenge by a pathogen or parasite. Much of this knowledge is due to the identification of a number of chemical and biological elicitors, some of which are commercially available for use in conventional agriculture. The biocontrol potential of Bacillus spp. and Pseudomonas spp in relation with their antagonizing attributes against plant viruses revealed their efficacy against Tobacco Mosaic Virus (TMV), Cotton 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 promoting rhizobacteria (PGPR) strains protect plants against viral infection through induction of systemic resistance. Studies were done to evaluate specific 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 artificially with chemicals such as salicylic acid 2,6-dichloro-isonicotinic 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 efficient use of different biological agents against plant viruses is a worthwhile approach in context of sustainable crop health management. 2. Biotic and Chemical Inducers of Systemic Acquired Resistance against Plant Viruses Plants develop a generalized resistance in response to infection

Investigates the ability of plant extracts from Lens culinaris to protect zucchini from the Zucchini yellow mosaic virus (ZYMV)

“…When 395 applying biotic inducers (M. jalapa, C. inerme, mixture and kombucha) pre- and post- virus 396 inoculation resulted in an increase the plant tolerant of infection. Also, these results were agreed 397 with 32 . Applications made prior to vaccination were found to be superior to vaccinations given afterward.…”

The Impact of Hydrogen Peroxide Against Cucumber Green Mottle Mosaic Virus Infection in Watermelon Plants

“…Chemical elicitors can generate systemic signals that lead to SAR induction. Hydrogen peroxide is one of the chemical inducers of SAR, which in turn signals the formation of pathogenesis-related proteins, and phytoalexins [33]. Hydrogen peroxide and superoxide act directly as second messengers in the regulation and expression of the genes encoding proteins responsible for oxidative stress response [13].…”

Priming Bean Seedlings to Boost Natural Plant Defenses Against Common Bacterial Wilt: Leaf Architecture, Leaf area, Foliage Water Content, and Plant Biomass Results (Part 3)

“…Chemical primers may activate a SAR response that provides a rapid and robust boost to plant immunity to minimize injury from most pathogen infections. Activation of such a response is systemic and has long-lasting, broad-spectrum properties [119][120][121][122][123]. SAR-induced immunity is not disease-specific but a broadspectrum response based on innate immunity.…”