World J Microbiol Biotechnol. 2025 Nov 8;41(11):439. doi: 10.1007/s11274-025-04647-6.
ABSTRACT
Salinization and overuse of chemical fertilizer restrict usable agricultural land and crop productivity. Biological candidates are needed for sustainable agriculture. Therein, purple nonsulfur bacteria (PNSB) can operate as both a plant growth promoter and a bioremediator. Therefore, the study aimed to determine the how much chemical N fertilizer can be reduced by the nitrogen-fixing purple nonsulfur bacteria (Nf-PNSB) and the effects of Nf-PNSB on the N dynamics, growth, and yield of rice with a two-season experiment. A factorial experiment with two factors having 4 levels each was conducted in a randomized complete block design with 4 replications and 8 plants replication-1. Each replication was a pot of soil with 8 rice plants. Factor A was N fertilizer percentages (100, 75, 50, and 0% N compared to the local recommended fertilization, LRF) and factor B was Nf-PNSB (no bacteria used, singly Rhodobacter sphaeroides S01 used, singly R. sphaeroides S06 used, and mixed R. sphaeroides S01 and S06 used, with a density of 1.6625 × 105 CFU g-1 dry soil). At the same N fertilizer level, treatments with the mixed Nf-PNSB outperformed the ones without bacteria, such as improved soil N availability and plant total N uptake and rice grain yield; and reduced soil Na+ and plant total Na uptake and proline content, in both seasons. Significant interaction effects between N fertilizer and PNSB were detected for most soil, plant, and yield traits. The mixed PNSB strain enhanced soil ammonium content and reduced Na⁺ accumulation under 100% N, but its effect was less consistent at 75% and 50% N. In both seasons, the 75% N + PNSB mixture treatment produced rice yields statistically similar to 100% N alone, although grain yield was slightly lower in season 2. Across N levels, PNSB supplementation generally reduced soil salinity and plant proline content while increasing N uptake. These results suggest that Nf-PNSB can partly compensate for chemical N reduction, particularly at 75% N, but the effects depend strongly on N level and season. Field trials are needed to confirm whether Nf-PNSB can reliably replace 25% of chemical N fertilizer under saline conditions.
PMID:41205123 | DOI:10.1007/s11274-025-04647-6
