Iqbal Ahmad
Aligarh Muslim University, India
Title: Synergistic effects of biofilm-producing PGPR strains on wheat plant colonization and growth under drought stress
Biography
Biography: Iqbal Ahmad
Abstract
Statement of the problem: Drought stress severely hampers crop productivity in many parts of the globe. Microbial strategies have been considered a promising option and are under scrutiny. It is hypothesized that indigenous bacterial strains exhibiting multiple plant growth promoting traits and interacting positively in planktonic and biofilm mode will effectively provide enhanced plant growth under a stress environment. Based on our previous screening study two distinct and novel biofilm-producing strains of PGPR, Bacillus subtilis (FAB1) and Pseudomonas azotoformans (FAP3) are included in this study. Biofilms provide bacteria to withstand stressful conditions in the soil system which may support the mitigation of crop stress in a sustainable manner. Limited studies have shown that biofilm-forming rhizobacteria support plants in alleviating water scarcity stress.The purpose of this study is to understand the role of individual and combined inoculation effects of strains on wheat plant growth under a water-stress environment.
Methodology & theoretical orientation: Bacterial isolates biofilms development on a microtiter plate, glass coverslip surface and seedling roots were evaluated and characterized by microscopic and scanning electron microscopy. The effect of water stress was studied on bacterial production of biofilms, EPC production and other traits. Rhizosphere and rhizoplane colonization by the FAB1 and FAP3 isolates, individually and mixed, was evaluated under ten-day water stress Selected bacterial isolates were inoculated on wheat plants in a soil pot system individually and in combination and evaluated for their performance under water stress conditions. Plant growth vegetative parameters, seed attributes, straw yield, and physiological parameters, and stress markers (CAT, SOD, GR, MDA, proline content) were analyzed.
Findings: In vitro interaction, two test bacterial strains showed synergy in both planktonic and biofilm modes of growth. The FAB1 and FAP3 strains exhibited specific and multifunctional PGP traits as well as better roots and rhizosphere colonization, which could provide sustained plant growth during drought. Moderate tolerance to ten-day drought conditions was noted when the individual strain was inoculated with wheat plants; however, the FAB1+FAP3 combined treatment significantly enhanced wheat survival during drought stress. The FAB1 and FAP3-induced modifications cooperatively conferred enhanced plant drought tolerance by regulating antioxidative systems.
Conclusion: The findings of the present investigation support further efforts to improve plant drought tolerance by engineering the biofilms and associated traits of rhizobacterial communities which needs in-depth investigation and exploiting promising indigenous strains for local application.