Evaluation of biofilm formation ability by biofilm growth promoting bacteria at the root surface of wheat (Triticum aestivum L.) and their effect on its yield

Rhizospheric growth-promoting-bacteria isolated from wild plants are introduced as biofilm forming PGPR. Due to their mode of action they behave as winner in plant root colonization process in the soil. Because of such advantage they are good candidates for the efficient inoculum production industries.

This experiment was performed under controlled conditions by inoculation of wheat seeds with nine biofilm forming growth promoting bacteria in a completely randomized design with three replications, and the growth characteristics of wheat were investigated under non-stress conditions.

The bacterial biofilm forming on wheat root was verified under confocal microscopic imaging. From the structural point of view, the diverse biofilms were detected among the bacteria. Total dry weight, stem dry weight, root dry weight, total shoot fresh weight, stem fresh weight and spike fresh weight, second leaf chlorophyll content, and wheat height were affected by the bacterial inoculation. Bacillus toyonensis 18-2 and Bacillus zhangzhouensis 23-3 were able to increase the total dry weight by 15% and 12%, respectively; compared to control treatment.

The biofilm formation by PGPR isolated from non-crops on the surface of wheat root showed that these bacteria have the ability to utilize wheat root secretions and settle in its rhizosphere. Due to the positive effect of the bacteria on wheat growth, the rhizosphere of non-crop plants can be considered as a suitable source for the isolation of new PGPR. The above mentioned two bacteria can be used as a potential candidate for the future experiments.