Abstract

One of the most detrimental abiotic factors affecting crop development and output, particularly in coastal regions, is salinity. The use of Plant Growth Promoting Rhizobacteria (PGPR) as a treatment can be a valuable tool for improving crop resilience and productivity in saline soils, which are a major constraint to agriculture worldwide. In the current study, bacterial isolates were obtained from soil samples that were collected from different coastal regions of Gujarat state, including Surat district (Dumas, Hajira, and Ubharat), Dwarka district, and Porbandar district (Madhavapur). Isolates were examined for their Plant Growth Promoting (PGP) activities to enhance wheat growth under salt stress. The production of ammonia, hydrogen cyanide (HCN), indole acetic acid (IAA) and gibberellic acid were among the PGPR activities that were used to screen the potential PGPR isolate. For salt stress tolerance, M3 isolate (Acinatobacter lowffi) grew well in 7.5% NaCl followed by 12.5% NaCl. Validation of nitrogen fixing isolates was performed using nifH gene amplification. Using 16S rRNA sequencing, significant isolate with salt tolerance and PGPR activity were molecularly characterised. Vigor index was measured for a plant's overall health and growth potential. Simultaneously, growth factors like seedling emergence, root development and leaf growth were taken into consideration. The results showed that five out of fifteen isolates obtained on nitrogen free Ashby’s agar showed high salt tolerance potential along with nitrogen fixation capacity as per PCR studies. However, the application of M3 was proven to be better halotolerant PGPR candidate under 7.5% and 12.5% salt stress compared to the control group that did not receive inoculum treatment and NPK half dose (T12 and T14). Seeds inoculated with M3 showed higher vigor index than the uninoculated seeds. The findings indicated that M3 demonstrated good potential as PGPR for salinity mitigation approach for coastal wheat production. Therefore, further studies on various wheat varieties and under field conditions are recommended.