Drought tolerance induction in wheat by inoculation of seeds with a novel growth-promoting bacteria

Abstract

The use of Plant Growth Promoting Rhizobacteria (= PGPR) to increase crop tolerance to biotic and abiotic stresses such as drought is considered a novel method to increase plant yield. For this purpose, several rhizobacteria isolates from the wheat rhizosphere were screened in Northwest Iran. After sieving the bacteria in the media with PEG6000 5 g/100 ml (PEG= Polyethylene Glycol), a total of 22 bacterial isolates were selected for further experiment. The study was performed as a factorial experiment with three replications. The effect of selected bacterial isolates in three different concentrations of PEG (−0.5, −0.9, −1.2-1.2 MPa) on wheat seeds was evaluated under standard laboratory conditions for two weeks, and major growth factors were measured. After analyzing the data, to confidently conclude the selection of better bacteria, PCA (=Principal Component Analysis) was used for the importance of traits. The first and second components were 49.15% and 15.4% of the changes, respectively which justified all traits. In the first main component, germination percentage (PG), germination rate (GV) and seed vigor index (SV) traits had high coefficients which indicated the greater importance of these traits in justifying the general changes in traits. Finally, three bacterial strains were selected as the desired bacteria on the base of these traits for greenhouse work. The results indicated that all the three bacteria strains increased the mean value of the studied traits compared to that of the control. Among the three selected strains, the 16srDNA region of the bacterium with the best performance was sequenced. The sequencing results showed that this bacterium belonged to Bacillus wiedmannii with 98.8% Likelihood.