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2.2.3 Lytic Enzymes

PGPR produce many hydrolytic enzymes through which plants get benefited. The
extracellular enzymes like cellulase, lipase, protease, chitinase have been playing vital role

for biocontrol (Markovich et al., 2003). These hydrolytic enzymes are capable of degrading a
wide variety of plants and other waste present in the soil through which this waste is

converted to simpler molecules from complex molecules. i.e. cellulose waste is degraded by
cellulase. Apart from this lysis of fungal cell wall (Mabood et al., 2014). The significance of

beta-1, 3-glucanase on the biocontrol activities of Lysobacter enzymogenes strain C3 against

Bipolaris leaf spot caused by Phytium sp. These properties protect plants from the attack of
pathogens. Chitinase production by Mycoparasitic and Trichoderma species exerts biocontrol

activities against R. necatrix and other plant pathogens (Harman et al., 2004). PGPR play an

important role through the activity of various lytic enzymes, which shields them from biotic
and abiotic stresses produced by Phytophthora sp. Rhizoctonia solani, and Pythium ultimum

Sclerotium rolfsii, Fusarium oxysporum (Nadeem et al., 2013). Biocontrol by PGPR by
producing enzymes such as chitinase, cellulose, b-1,3 glucanase, protease, or lipase causes

induction of lysis of fungle cell walls (Chet et al., 1994).

3. Applications of PGPR as Multifunctional Agents

Efficiency of PGPR in enhancing crop productivity varies under field, laboratory and
greenhouse condition. As soil is an unpredictable environment, achieving an intended result

is often difficult. PGP traits work additively and not independent of each other. PGP traits
such as P solubilization, N2 fixation, 1-aminocyclepropane-1-carboxylate (ACC) deaminase

activity, siderophore production, antifungal activity, IAA biosynthesis etc. by PGPR improve

plant growth and yield (Gupta et al., 2015). The direct and indirect mechanisms of action of
PGPR based over Nitrogen fixation, Phosphorous availability, Potassium solubilization. Ion

chelation, modulation of phytohormones, HCN production etc have been illustrated. Global
dependence on use of chemicals for agriculture can also be drastically reduced by wide

scale application of PGPR because this technology is readily accessible to the farmers in

developing countries (Goswami et al., 2016).
Conclusion

Plant growth promoting rhizobacteria (PGPR) are a group of free-living bacteria that colonize

the rhizosphere and contribute to increased growth and yield of crop plants are generally
disseminated among all environmental specialty. Completely different instruments of PGPR

facilitate to understand their job in nature as plant development propellants and specialists of

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