Role of plant growth-promoting rhizobacteria and their exopolysaccharide in drought tolerance of maize

Abstract

The present study deals with the isolation and characterization of exopolysaccharides (EPS) produced by the plant growth-promoting rhizobacteria (PGPR) from arid and semiarid regions of Pakistan, and to investigate the drought tolerance potential of these PGPR on maize when used as bioinoculant alone and in combination with their respective EPS. Three bacterial strains Proteus penneri (Pp1), Pseudomonas aeruginosa (Pa2), and Alcaligenes faecalis (AF3) were selected as EPS-producing bacteria on the basis of mucoid colony formation. All these strains were gram negative, motile, and positive for catalase. Strain Pp1 was positive for oxidase test and was phosphate solubilizing, while Pa2 and AF3 were negative. The isolated strains were sequenced using 16SrRNA. Total soluble sugar, protein, uronic acid, emulsification activity, and Fourier-transformed infrared spectroscopy of EPS were determined. Drought stress had significant adverse effects on growth of maize seedlings. Seed bacterization of maize with EPS-producing bacterial strains in combination with their respective EPS improved soil moisture contents, plant biomass, root and shoot length, and leaf area. Under drought stress, the inoculated plants showed increase in relative water content, protein, and sugar though the proline content and the activities of antioxidant enzymes were decreased. The Pa2 strain isolated from semiarid region was most potent PGPR under drought stress. Consortia of inocula and their respective EPS showed greater potential to drought tolerance compared to PGPR inocula used alone.

Scrutinizing of Rhizobacterial Isolates for Improving Drought Resilience in Maize (Zea mays)

“…Similarly, maize plant inoculated with Burkholderia phytofirmans strain PsJN showed significant increase in root biomass by 70 and 58% in Mazurka and Kaleo cultivars of maize (Naveed et al, 2014). The relation between deeper root system drought tolerance has also been observed by other researchers in maize crop (Hund et al, 2011;Naseem and Bano, 2014).…”

Role of Acinetobacter sp. CS9 in Improving Growth and Phytoremediation Potential of Catharanthus longifolius under Cadmium Stress

“…Some researchers have revealed that plants exhibit reduced total sugar contents under stress [48]. However, inoculation of growth-promoting bacteria enhance both total sugar and protein contents in metal-stressed plants and help in alleviating relative stress [49][50].…”

Bacterias endófitas de la raíz en líneas de maíces tolerantes y susceptibles a sequía

“…Endophytic bacteria can induce tolerance to abiotic stresses such as salinity and drought, while some populations confer tolerance to specific stress factors and are responsible for the survival of plants under these particular environmental conditions (Gond et al, 2015; Montañez et al, 2011). Thus, the microorganisms that establish positive interactions with plant roots play a key role in cropping systems and have promising biotechnological potential to be used in sustainable agriculture.In Mexico there are no studies on endophytic bacterial communities in roots of drought Así mismo, se ha demostrado la eficiencia con la inoculación de estas bacterias en maíz promoviendo tolerancia al stress por sequía (Fan et al, 2015), mediado por el incremento de la longitud y biomasa de la raíz mejorando la absorción de agua y nutrientes (Naseem y Bano, 2014;Yasmin et al, 2013). Las bacterias endófitas pueden inducir tolerancia contra enfermedades abióticas como salinidad y sequía, mientras que algunas poblaciones confieren tolerancia a factores de estrés específico y son responsables de la supervivencia de las plantas bajo esas condiciones particulares del ambiente (Gond et al, 2015; Montañez et al, 2011).…”

“…In Mexico there are no studies on endophytic bacterial communities in roots of drought Así mismo, se ha demostrado la eficiencia con la inoculación de estas bacterias en maíz promoviendo tolerancia al stress por sequía (Fan et al, 2015), mediado por el incremento de la longitud y biomasa de la raíz mejorando la absorción de agua y nutrientes (Naseem y Bano, 2014;Yasmin et al, 2013). Las bacterias endófitas pueden inducir tolerancia contra enfermedades abióticas como salinidad y sequía, mientras que algunas poblaciones confieren tolerancia a factores de estrés específico y son responsables de la supervivencia de las plantas bajo esas condiciones particulares del ambiente (Gond et al, 2015; Montañez et al, 2011).…”

“…It has also been shown that inoculating maize with these bacteria efficiently promotes drought stress tolerance (Fan et al, 2015) as a result of the increase in root length and biomass, which in turn improves water and nutrient absorption (Naseem and Bano, 2014;Yasmin et al, 2013). Endophytic bacteria can induce tolerance to abiotic stresses such as salinity and drought, while some populations confer tolerance to specific stress factors and are responsible for the survival of plants under these particular environmental conditions (Gond et al, 2015; Montañez et al, 2011).…”