USE OF IAA-PRODUCING PLANT GROWTH-PROMOTING BACTERIA FOR THE AMELIORATION OF SALT AND DROUGHT STRESS IN WHEAT

Abstract

The major abiotic stresses responsible for the loss of significant agricultural produce are high soil salinity and drought. Plant growth-promoting bacteria can help plant resilience to such stresses through various mechanisms. This study aimed to explore the plant growth promotion potential of rhizospheric bacteria under conditions of high salinity and drought in wheat. Rhizospheric soil samples were screened for bacteria possessing plant growth-promoting traits. The isolates were further evaluated for salt tolerance, drought tolerance and indole-acetic acid (IAA) production under high salinity and drought conditions. Plant growth-promotion studies were conducted, followed by plant root length, shoot length and fresh weight measurements. Pot assays revealed that coating wheat seeds with the IAA-producing salt-tolerant isolates had a favourable impact on plant parameters under salt stress, wherein an increase between 2.4 – 2.6-fold, 1.3 – 1.6-fold, 1.4 – 1.8-fold was observed in the root length, shoot length and fresh weight of the inoculated plants respectively. In the case of IAA-producing drought-tolerant isolates, no increase was observed in the shoot length or root length. However, an increase of 1 – 2-fold was seen in the fresh weight of the inoculated plants compared to the control under drought conditions. These findings suggest that inoculation of wheat seeds with AK-8, identified as Acinetobacter junii, and FS-1, identified as Klebsiella aerogenes, can be harnessed as a strategy for ameliorating salt and drought stress in wheat, thereby increasing crop yield.