Isolation and Characterisation of Bacteria From an Extremely High Boron and Salinity-Tolerant Puccinellia distans (Jacq.) Parl. Rhizosphere and Their Potential Impact on the Growth of Bread Wheat (Triticum aestivum L.)

Abstract

Boron toxicity and salinity are major abiotic stress factors that cause significant yield losses, particularly in arid and semi-arid regions. Hyperaccumulator plants, such as Puccinella distans (Jacq.) Parl. from Kirka, exhibit remarkable tolerance to these stresses. This study isolated nine boron-tolerant and six salinity-tolerant bacterial strains from the rhizosphere of P. distans. Using BLAST analysis of 16S rRNA sequences, the boron-tolerant bacteria were identified as Sphingobacterium detergens (three strains), Achromobacter spanius, Pseudomonas extremorientalis, Olivibacter soli, Puccinella poae, Zhihengliuella halotolerans and Chryseobacterium sp., while the salinity-tolerant strains included Bacillus toyonensis, B. muralis, Staphylococcus warneri, Staphylococcus aureus (two strains) and Arthrobacter aurescens. Among these, P. poae stood out as a promising plant growth-promoting rhizobacteria (PGPR) candidate. A greenhouse pot experiment demonstrated that inoculating Triticum aestivum L. with P. poae under varying boron doses significantly enhanced plant growth. Notable increases were observed in plant height, root length, stem fresh weight and emergence ratio. These findings highlight the potential of P. poae as an eco-friendly microbial fertiliser to enhance crop resilience in boron-affected areas and offer a sustainable alternative to chemical fertilisers, thus improving agricultural productivity under abiotic stress conditions.