Plant Growth-Promoting Rhizobacteria Improve Rice Response to Climate Change Conditions

Abstract

Rice is one of the most important crops in the world and is considered a strategic crop for food security. Furthermore, the excessive use of chemical fertilizers to obtain high yields causes environmental problems. A sustainable alternative includes taking advantage of beneficial bacteria that promote plant growth. Here, we investigate the effect of five bacterial biofertilizers from halophytes on growth, and we investigate photosynthetic efficiency in rice plants grown under saline conditions (0 and 85 mmol L−1 NaCl) and future climate change scenarios, including increased CO2 concentrations and temperature (400/700 ppm and 25/+4 °C, respectively). Biofertilizers 1–4 increased growth by 9–64% in plants grown with and without salt in both CO2- temperature combinations, although there was no significant positive effect on the net photosynthetic rate of rice plants. In general, biofertilizer 1 was the most effective at 400 ppm CO2 and at 700 ppm CO2 +4 °C in the absence of salt. Inocula 1–5 also stimulated plant length at high CO2 levels without salt. Finally, the positive effect of biofertilization was attenuated in the plants grown under the interaction between salt and high CO2. This highlights the significance of studying biofertilization under stress interaction to establish the real potential of biofertilizers in the context of climate change conditions.

Keywords

• bacterial consortium
• efficiency of PSII photochemistry
• elevated atmospheric CO₂
• gas exchange
• inoculation
• PGPR