Impact of Native ST-PGPR (Bacillus pumilus; EU927414) on PGP Traits, Antioxidants Activities, Wheat Plant Growth and Yield under Salinity

The rhizobacterial isolate ‘121’ identified as Bacillus pumilus-EU927414, which was a rich source of PGP traits like IAA, gibberellins, phosphate solubilisers and siderophore production at 8% NaCl (w/v). This isolate showed synergistic behaviour of PGP traits with its compatible ST-PGPRs like three-fold increases in IAA content in T9 combination (EU927414-B. pumilus + EU927408-B. aquimaris +EU742146-Bacillus sp.). Synergistic behaviour of B. pumilus-EU927414 was also observed in the case of ACC deaminase activities in T9 at 8% NaCl (w/v). Growth and yield of wheat crop in saline soil (ECe>3.4 dSm⁻¹) were enhanced by the inoculation of native ST-PGPR (salt tolerantplant growth promoting rhizobacteria) under half a dose of recommended synthetic fertilisers (N: P: K) as observed in two successive cropping seasons. Salinity tolerant wheat cultivar K-7903 was used to evaluate the effect of ST-PGPRs in the saline field. Antioxidants activities like SOD, APX, CAT and GR along with proline, TSS, RS content were increased in T9 treated leaves of wheat plant at 60 days, followed by 90 days. The N, P and K contents in plant leaf were significantly increased due to inoculation of compatible ST-PGPRs including B. Pumilus-EU927414. The results showed reduced sodium content in T9 treated wheat plant's leaf at 90 days, followed by 60 days. The yield of wheat was 24% increases with the inoculation of T9 combination, followed by T3 combination (EU927414-B. pumilus + EU927412-Pseudomonas medicona + EU927410-Arthrobacter sp.), when compared with control.