Molecular and Biochemical Characterization, Antimicrobial Activity, Stress Tolerance, and Plant Growth-Promoting Effect of Endophytic Bacteria Isolated from Wheat Varieties

Abstract

Endophytic bacteria have been utilized as an alternative source to chemical fertilizers and pesticides to enhance plant productivity and defense mechanisms against biotic and abiotic stress. Five endophytic bacterial strains were isolated from the seeds of three different Pakistani wheat varieties (Ghaneemat-e-IBGE, Atta-Habib, and Siren). The isolated strains AH-1, S-5, S-7, GI-1, and GI-6 showed phylogenetic similarity with Bacillus altitudinis, B. aryabhattai, B. wiedmannii, Pseudomonas aeruginosa, and Burkholderia gladioli, respectively. All strains showed catalase activity (except AH-1) and Indole-3-acetic acid production, with the highest concentration (16.77 μg·mL−1) found for GI-6, followed by S-5 (11.5 μg·mL−1), nitrogen assimilation (except S-7), phosphorus solubilization (except S-7 and AH-1), and ability to produce siderophores, with maximum productions for GI-6 (31 ± 3.5 psu) and GI-1 (30 ± 2.9 psu). All five analyzed strains possessed antimicrobial activity, which was particularly strong in GI-6 and S-5 against Klebsiella pneumonia, Escherichia coli, and Bacillus subtilis. Increasing salinity stress with NaCl negatively affected the bacterial growth of all isolates. However, strains GI-6 and S-5 showed salt tolerance after three days of incubation. A drought tolerance test resulted in a negative impact of poly ethylene glycol on bacterial growth, which was, however, less pronounced in GI-6 strain. The GI-6 strain revealed growth-promoting effects on inoculated wheat plants.

Stress-Tolerant Endophytic Isolate Priestia aryabhattai BPR-9 Modulates Physio-Biochemical Mechanisms in Wheat (Triticum aestivum L.) for Enhanced Salt Tolerance

“…Ammonia transporters are found in some PGPR strains and are assumed to be engaged in reabsorbing NH 4 + released by NH 3 diffusion across microbial membranes [ 77 ]. Salt-tolerant endophytic PGPR strains cultivated on liquid media supplemented with salt have recently been found to produce HCN and ammonia [ 78 , 79 ].…”

In vitro Screening of Sunflower Associated Endophytic Bacteria With Plant Growth-Promoting Traits

“…The presence of endophytic bacteria in host plants and their ability to synthesize growth hormones can significantly enhance seedling growth, development, and elongation of lateral roots and cell differentiation (Shahzad et al, 2017). In this study, the combination of culturing and molecular techniques in the characterization of sunflower roots and stem-associated endophytic bacteria has been reported (Tiwari and Thakur, 2014;Bahmani et al, 2021;Shah et al, 2022). The biochemical characterization reflected the most identifiable Gram-positive compared to the Gram-negative bacterial isolates.…”

Characterization of siderophores from Escherichia coli strains through genome mining tools: an antiSMASH study

“…Some of the recent papers are reviewed here. In an interesting study carried out by Shah et al ( 2022 ), the production of siderophores was investigated from five endophytic bacterial strains of the Pakistani wheat varieties. Endophytic bacteria are recently considered as a support for the plant productivity and defense system.…”

“…Endophytic bacteria are recently considered as a support for the plant productivity and defense system. Shah et al ( 2022 ) found out that some of the strains have an ability to synthesize siderophores which could be associated with growth-promoting effects for the commercial plants. Podgórska-Kryszczuk et al ( 2022 ) also studied biological control of pathogenic Fusarium spp.…”