Abstract
The inconsistent vitality and efficiency of plant growth promoting bacteria (PGPB) are technical limitations in the application of PGPB as biofertilizer. To improve these disadvantages, we examined the potential of micro Dielectric Barrier Discharge (DBD) plasma to enhance the vitality and functional activity of a PGPB, Bacillus subtilis CB-R05. Bacterial multiplication and motility were increased after plasma treatment, and the level of a protein involved in cell division was elevated in plasma treated bacteria. Rice seeds inoculated with plasma treated bacteria showed no significant change in germination, but growth and grain yield of rice plants were significantly enhanced. Rice seedlings infected with plasma treated bacteria showed elevated tolerance to fungal infection. SEM analysis demonstrated that plasma treated bacteria colonized more densely in the broader area of rice plant roots than untreated bacteria. The level of IAA (Indole-3-Acetic Acid) and SA (Salicylic Acid) hormone was higher in rice plants infected with plasma treated than with untreated bacteria. Our results suggest that plasma can accelerate bacterial growth and motility, possibly by increasing the related gene expression, and the increased bacterial vitality improves colonization within plant roots and elevates the level of phytohormones, leading to the enhancement of plant growth, yield, and tolerance to disease.
Highlights
Increasing population, global warming, and environmental pollution have become emerging threats to modern agriculture, resulting in food shortages worldwide
The efficiency of plant growth promoting bacteria (PGPB) or rhizobacteria (PGPR) as biofertilizer is dependent on their survival ability, competence, and interaction with other microbes in the environment, as well as their ability to promote plant growth
The atmospheric pressure non-thermal plasma technology that is demonstrated in our study can be a promising tool for enhancing the vitality and functional activity of PGPB through molecular and hormonal regulation
Summary
Global warming, and environmental pollution have become emerging threats to modern agriculture, resulting in food shortages worldwide. Biofertilizers using PGPB have demonstrated several advantages in agricultural practices, such as environmentally friendly nutrition, improvement of soil fertility, and regulation of biotic and abiotic stresses[10,12,13]. The active use of PGPB sometimes encounters challenges in agricultural application, because of the inconsistent efficiency and vitality of PGPB14. Atmospheric pressure non-thermal plasma has been suggested as a potential tool to improve the vitality and functionality of PGPB. We investigated the potential of plasma to enhance the vitality and functional activity of a PGPB, in order to eventually promote plant growth, development, and stress regulation. Bacillus subtilis CB-R05 (PGPB) that was previously isolated from Korean rice cultivar as a nitrogen fixing endophytic bacterial strain[39] was used in this study Functional improvement of this bacterial strain by plasma was examined
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
