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resistance, HCN Legumes

production

Rhizobia N2 fixation Rice (Yanni et al., 2001)

Rhizobia Auxin production Pepper, tomato, (Flores‐Félix et al.,

carrot, lettuce 2013; García-Fraile

et al., 2012)

Rhizobia ACC deaminase Pepper, tomato, (Ahmad et al., 2013;

synthesis, Siderophore mung beans García-Fraile et al.,
production 2012)

Rhizobium P solubilization Common Bean (Ahemad et al.,
leguminosarum 2014)

Enterobacter P solubilization Tomato (Otieno et al., 2015)

agglomerans

Bradyrhizobium P solubilization Soybean (Gopalakrishnan et

japonicum, al., 2015)
Pseudomonas sp,

Pseudomonas

putida

2. Mechanisms of Action of Plant Growth Promoting Rhizobacteria

The microorganisms of the rhizosphere include both deleterious and beneficial components
that have the potential to influence plant growth and crop yield significantly. The beneficial

rhizobacteria include the symbiotic rhizobia, certain actinomycetes and mycorrhizal fungi
and free-living bacteria, increase the availability of nutrients or plant growth substances to

plants and/or suppress parasitic and non-parasitic pathogens (Persello‐Cartieaux et al., 2003).

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

(Kloepper et al., 1981). PGPR can affect plant growth by different direct and indirect

mechanisms (Glick, 1995; Gupta et al., 2000). PGPR revitalize plant growth directly by
altering available nitrogen from atmosphere, Genus of Klebsiella, Bacillus and Pseudomonas

can solubilize phosphate (Rodrı guez et al., 1999). Only monobasic and dibasic forms of
phosphates are soluble forms in soil and can be absorbed by plants (Bhattacharyya et al.,

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