Bioprospecting plant growth promoting endophytic bacteria isolated from Himalayan yew (Taxus wallichiana Zucc.)

The present study aims to investigate the endophytic bacteria, isolated from the roots of Taxus wallichiana Zucc. and designated as GBPI_TWL and GBPI_TWr, for their plant growth promoting traits. On the basis of phenotypic and molecular characters, the bacteria are identified as species of Burkholderia and Enterobacter, respectively. Both the bacteria could grow at wide range of temperature (5-40 °C, opt=25 °C) and pH (1.5-11.0, opt = 6-7), and tolerate salt concentration up to 12 %. While both the bacterial endophytes possessed siderophore, HCN, ammonia, and salicyclic acid producing abilities, GBPI_TWL showed IAA and ACC deaminase producing abilities, in addition. The bacteria were found to be potential phosphate solubilizers at wide temperature range (5-35 °C) by utilizing tricalcium, iron, and aluminium phosphate as substrate. Further, the bacterial isolates produced phytase and phosphatase enzymes in both acidic and alkaline conditions. Positive influence of the inoculation with the bioformulations of GBPI_TWL and GBPI_TWr was demonstrated on the test crops namely rice (Oryza sativa) and soybean (Glycine max) with respect to physico-chemical and plant growth parameters in net house experiments. The study will have implications in developing bioformulations, specifically for low temperature environments, in view of environmental sustainability.

Keywords: Bacterial endophytes; Burkholderia sp.; Enterobactor sp.; Himalayan Yew; Phosphate solubilization; Plant growth.