Role of PGPR in the reclamation and revegetation of saline land

Abstract

A field experiment was conducted to investigate the effect of PGPR inoculation on growth and yield of maize as well as on reclamation of saline sodic soil of Soil Salinity Research Institute Pindi Bhattian Pakistan, during 2015-16. Seed of maize genotype "Islamabad Gold" were soaked (2-3 h) prior to sowing in the broth culture of 4 bacterial strains i.e. Pseudomonas putida (accession no. KX580766), Pseudomonas fluorescens (accession no. KX644132), Exiguobacterium aurantiacum (accession no. KX580769), Bacillus pumilus (accession no. KX580768) and Lysinibacillus sphaericus (accession no. KX580767). In vitro analysis of bacteria confirmed that they metabolize ACC deaminase, solubilize insoluble phosphate and produce significant quantity of auxin in the presence of L-tryptophan. Inoculation of maize with bacteria along with application of 1L inocula / treatment in the field gave a significant (P = 0.05) increase in germination (76%), leaf chlorophyll (24%), proline (65%), anthocyanin (38%) and soluble sugar content (56%). P. putida inoculation resulted in maximum increase in plant height, leaf area, no of grains cob -1 (459.8), 1000 grain weight (330.9 g) and grain yield (3.25 tha -1 ). P. fluorescens was least effective. The rhizosphere soil analysed after harvesting exhibited significant decrease in electrical conductivity (49%), sodium absorption ratio (98%), and cation exchange capacity (94%) concomitant with a significant increase in organic matter (52%), NO3-N (37%), available P (48%) and K (31%). The highest efficiency of P. putida may be attributed to the maximum ACC deaminase activity, higher production of indole acetic acid and greater potential for Phosphate solubilization. The favorable effects of PGPR were more pronounced in the successive year 2016.

<em>Allium cepa </em>L. <em>s</em>eed inoculation with a consortium of plant growth-promoting bacteria: effects on plant growth and development and soil fertility status and microbial community

“…In both experimental fields, the application of PGPB consortium increased total organic carbon, organic matter and available P and allowed to keep higher concentrations of the other nutrients. These findings have been already reported by other authors [14,15] and can be ascribed to the PGPB capability of nutrient mobilization and to atmospheric nitrogen fixation [2]. The ecological indexes calculated on NGS results showed that seed bacterization was able to positively influence soil microbial community composition of both varieties, by increasing microbial biodiversity.…”

Potential of Salt Tolerant PGPR in Growth and Yield Augmentation of Wheat (Triticum aestivum L.) Under Saline Conditions

“…However, only limited data is available regarding the PGP activities showed by E . aurantiacum ( Ullah and Bano, 2019 ). Strahsburger et al (2018) reported the draft genome of E .…”

“…aurantiacum substantially increased the growth and yield of wheat crop grown under saline conditions. It may be due to the fact that these PGPR were able to metabolize ACC deaminase, solubilize insoluble phosphate minerals and produce a significant quantity of IAA ( Ullah and Bano, 2019 ). However, in our study, B. pumilus (T 3 ) and E .…”

“…Three pre-characterized halotolerant PGPR strains, Pseudomonas fluorescens (Accession # KX644132 ), Bacillus pumilus (Accession # KX580768 ) and Exiguobacterium aurantiacum (Accession # KX580769 ) were collected from NBRC, Microbial Physiology Lab, SEBD, NIBGE, Faisalabad. The salt tolerance profiling on the basis of minimal inhibitory concentration and PGP characteristics (phosphate solubilization, IAA production and ACC metabolism) of these strains were assessed (qualitatively and quantitatively) based on selective media in a previous study ( Ullah, 2019 ). Ullah and Bano (2019) demonstrated that these PGPR have significantly improved the growth and yield of maize grown in saline sodic soil as well physico-chemical properties of soil.…”

“…The salt tolerance profiling on the basis of minimal inhibitory concentration and PGP characteristics (phosphate solubilization, IAA production and ACC metabolism) of these strains were assessed (qualitatively and quantitatively) based on selective media in a previous study ( Ullah, 2019 ). Ullah and Bano (2019) demonstrated that these PGPR have significantly improved the growth and yield of maize grown in saline sodic soil as well physico-chemical properties of soil. Compatibility of these strains was also assessed using a cross streak method ( Semenov et al, 2007 ) on NaCl supplemented LB-medium prior to seed inoculation.…”