Bacterium Pseudomonas spp. olive green (OG) was isolated from marine water, yet, it was characterized as plant growth promoting bacterium (PGPB). Multiple plant growth promoting traits of OG isolate were determined in vitro. It was tested positive for Indole-3-acetic acid (IAA) production with 29 mg ml (1 of IAA yield, phosphate solubilization with 34 mg ml (1 solubilization of Tri-calcium-phosphate and it showed maximum of 32 mg ml (1 of ammonia production. OG isolate was affirming siderophore production, hydrocyanic acid (HCN) production and catalase production. 16S rRNA gene sequence comparison was used to identify the isolate which showed its closest neighbor to be Pseudomonas fluoroscens strain BCPBMS-1. Efficacy of this PGPB was tested on the seedling growth of two test plants chickpea and green gram. Both the test plants treated with OG-based talc bioformulation showed significant growth promotion. Chickpea showed enhanced overall fresh biomass by 24%, overall dry biomass by 27% was observed after 15 days of seeded in pots. Green gram showed enhanced overall dry biomass by 28% was observed after 10 days of seeded in pots.

Bacterium Paenibacillus mucilaginosus strain N3 was isolated from agricultural farm soil (located at Boriavi village, Gujarat, India). Isolate showed an evidence of non-symbiotic nitrogen fixation, when grown in nitrogen-free bromothymol blue growth medium. It was tested positive for direct plant-growth-promoting traits like Indole-3-acetic acid production, solubilization of Tri-calcium-phosphate, and ammonia production. Further, N3 isolate was tested positive for siderophore production of catecholate type and catalase production as an indirect plant-growth-promoting trait. Biochemical tests along with 16s rRNA gene sequence analysis confirmed the strain N3 to be P. mucilaginosus. To determine its efficacy as a plant-growth-promoting rhizobacteria (PGPR), its talc-based biofertilizer was prepared and tested on the growth of green gram (Vigna radiata). Seeds treated with this biofertilizer showed an increase in overall dry biomass by 17% and sapling length by 28% (as compared to non-treated controls) after 10 days of sowing in pots. Thus, multiple plant-growth-promoting traits of P. mucilaginosus N3 determined in vitro along with its ability to promote growth in green gram in vivo we characterize this strain as an efficient PGPR.

Species belonging to the genus of Pseudomonas are known to possess metabolic versatility and are capable of adapting to various environments. One such strain BG, possessing urease activity, was isolated from marine water from the Gulf of Khambhat, Gujarat. 16S rRNA gene sequence analysis was performed to identify the isolate, which showed that it was the closest neighbor to be Pseudomonas aeruginosa strain BS8. Strain BG was accessed (meant to be assessed?) for multiple plant growth promoting and biocontrol traits. It tested positive for indole-3-acetic acid (IAA) production with 19 mg ml -1 of IAA yield, phosphate solubilization with 13 mg ml -1 solubilization of tri-calcium-phosphate and it showed maximum of 27 mg ml -1 of ammonia production. Further, BG isolate could produce hydrocyanic acid, siderophore, catalase and showed growth inhibition of Aspergillus flavus and Fusarium oxysporum f. sp. cubense confirming its potential antifungal activity. The marine isolate also showed 17.92 ± 1.79 unit min -1 ml -1 urease activity, and further, the presence of genes responsible for urease enzyme in strain BG was identified by amplification using gene specific primers. Talc based biofertilizer using strain BG was prepared and tested on seedling growth of Chickpea, where biofertilizer treated seeds showed enhanced growth. Thus, it was concluded that marine P. aeruginosa BG showed plant growth promotion and biocontrol abilities along with urease activity.