The cellular components of cucumber seedlings after primed with plant growth promoting rhizobacteria, Bacillus subtilis Bs008

This work aimed at investigating the changes in cellular compositions of cucumber seedlings as enhanced by plant growth promoting rhizobacteria, Bacillus subtilis Bs008 using the Fourier transforminfrared spectroscopy (FT-IR). The objective of this study was to test the hypothesis that Bs008 stimulates production of plant cellular components involved in metabolism and growth development mechanisms. Cucumber vegetative propagation and treatment with Bs008 or with sterile distilled water was done in sterile soil, after incubation for 28 days, Bs008 treated cucumber seedlings had more lateral root, longer roots, shoot length and greater biomass than the control. We also focused on plant cellular composition, and cucumber seedling tissues from the two treatments were harvested for FT-IR analysis. FT-IR analyses revealed that lipid was highly accumulated in response to the strain Bs008. The cucumber seedling treated with the beneficial bacteria B. subtilis strain Bs008 shows the beta sheet secondary structure and  apparently appeared with high polysaccharide content but the lipid content was decreased when compared with those of the cucumber seedling treated with distilled water. Our results demonstrate that Bs008 can enhance plant growth under laboratory conditions by direct stimulation of cucumber polysaccharides.   Key words: Plant growth promotion, Bacillus subtilis Bs008, cucumber, cellular composition, FTIR spectroscopy.