Gluconacetobacter diazotrophicus Pal5 Enhances Plant Robustness Status under the Combination of Moderate Drought and Low Nitrogen Stress in Zea mays L.

Muhammad Aammar Tufail, María Touceda-González, Ilaria Pertot and Ralf-Udo Ehlers

INFORMATIVE ABSTRACT - Gluconacetobacter diazotrophicus Pal5 is an endophytic diazotrophic bacterium known for stimulating plant growth and fixing the amount of nitrogen received by plants like sugarcane, coffee tree, tomatoes and pineapple. The study was conducted to analyse the effect of the bacterium on the amelioration of the individual and combined effects of drought and nitrogen stress in maize plants. The analysis was based on a pot experiment that considered the answers of maize plants cultivated under drought stress and in soil with a low nitrogen concentration to different treatments of G. diazotrophicus seed inoculation (considering also the “no treatment” option).

The results of this experiment showed how the plants inoculated with the G. diazotrophicus Pal5 bacterium increase plant biomass, chlorophyll content, plant nitrogen uptake, and water use efficiency. Moreover, it was detected under combined moderate stress an increase in copy numbers of the bacterium and N-fixation linked genes. However, the severe stress treatments negatively affected the endophytic colonization of bacteria. In conclusion, researchers can now consider G. diazotrophicus Pal5 as an effective tool to increase maize crop production under drought conditions with low application of nitrogen fertilizer.