Isolation of low temperature surviving plant growth – promoting rhizobacteria (PGPR) from pea (Pisum sativum L.) and documentation of their plant growth promoting traits

• We identified 4 PGPR strains from the IGP of India.
• These PGPR strains exhibited highest resistance to nalidixic acid and least with ciprofloxacin.
• All screened PGPR strains can be used under cold stress, environmental condition.
• All PGPR strains can be used as indigenous potential biofertilizer for crop production.

In the present investigation, four low temperature surviving PGPR strains were isolated from root nodules of pea (Pisum sativum L.) plant growing widely in different agro-climatic regions of the great northern Indian plains made fertile by the mighty river Ganges. All the PGPR strains were able to show growth at upto 5 °C in yeast extract-mannitol-mineral salts broth, but isolates PR-12-12 and PR-12-15 showing significantly higher cell growth as compared to other PGPR strains. In order to study their in-vitro characteristics, all PGPR strains are able to solubilize phosphate (Pi) on Pikovskaya agar plates ranging from 16–25 mm (7 DAI). Besides solubilizing Pi they produced phytohormone indole-3-acetic acid (IAA) in the range of 62.7–198.1 μg/ml. These PGPR strains exhibited highest resistance to DNA gyrase inhibitor antibiotic nalidixic acid and least resistance to ciprofloxacin. The results strongly suggest that the PGPR strains characterized under present investigation may be useful as a novel biofertilizers for crop production at low temperature of the Indo-Gangetic Plain (IGP) of India.