Effect of osmotic stress on in vitro plant growth hormone production by osmotolerant bacteria isolated from chilli phyto microbiome

Abstract

The present study was conducted to determine the effect of osmotic stress on the plant growth hormone production by six osmotolerant plant growth promoting bacterial strains. These strains originated from the phytomicrobiome of chilli cultivated in the drought prone areas of Andhra Pradesh. They possessed multiple plant growth promotion traits including the ability to produce a variety of plant growth hormones. The effect of osmotic stress on the plant growth hormone production was determined by High Performance Liquid Chromatography (HPLC) under normal and in vitro osmotic stress conditions using 25% Poly Ethylene Glycol (PEG) 8000. In general, it was observed that osmotic stress impacted the plant growth hormone production of the isolates, but nevertheless plant hormones were detected in all the bacterial strains. An exception to this was the cytokinin molecule zeatin riboside, which was produced at higher levels by five of the six bacterial isolates under osmotic stressed conditions.