Mitigation of water scarcity with sustained growth of Rice by plant growth promoting bacteria

Roots of synthetic ecology: microbes that foster plant resilience in the changing climate

Microbes orchestrate nearly all major biogeochemical processes. The ability to program their influence on plant growth and development is attractive for sustainable agriculture. However, the complexity of microbial ecosystems and our limited understanding of the mechanisms by which plants and microbes interact with each other and the environment make it challenging to use microbiomes to influence plant growth. Novel technologies at the intersection of microbial ecology, systems biology, and bioengineering provide new tools to probe the role of plant microbiomes across environments. Here, we summarize recent studies on plant and microbe responses to abiotic stresses, showcasing key molecules and micro-organisms that are important for plant health. We highlight opportunities to use synthetic microbial communities to understand the complexity of plant-microbial interactions and discuss future avenues of programming ecology to improve plant and ecosystem health.

Potential of Drought Tolerant Rhizobacteria Amended with Biochar on Growth Promotion in Wheat

Drought stress is the prime obstacle for worldwide agricultural production and necessitates innovative strategies for enhancing crop resilience. This study explores the efficacy of plant growth-promoting rhizobacteria (PGPR) and biochar (BC) as sustainable amendments for mitigating the effects of drought on wheat growth. Multiple experiments were carried out on isolated strains to assess their drought tolerance potential and multiple plant growth-promoting attributes. Experiments in the laboratory and natural environment were conducted to assess the impact of plant growth-promoting rhizobacteria, biochar, and their synergistic application on various growth parameters of wheat. The results revealed that the drought-tolerant PGPR strains (Bacillus subtilis and Bacillus tequilensis), alongside biochar (rice husk), alleviated the phytotoxic impact of drought by increasing the root length from 17.0% to 70.0% and shoot length from 30.0% to 82.0% as compared to un-inoculated stressed controls. The total chlorophyll and carotenoid contents of the plants were substantially increased to 477% and 423%, respectively, when biochar and PGPR were applied synergistically. Significant enhancements in membrane stability index, relative water content, proline, and sugar level were achieved by combining biochar and bacterial strains, resulting in increases of 19.5%, 37.9%, 219%, and 300%, respectively. The yield of wheat in terms of plant height, spike length, number of spikelets per spike, and number of grains per spike was enhanced from 26.7% to 44.6%, 23.5% to 62.7%, 91.5% to 154%, and 137% to 182%, respectively. It was concluded that the biochar-based application of PGPR induced drought tolerance in wheat under water deficit conditions, ultimately improving the production and yield of wheat.

Coinoculation with Growth-Promoting Bacteria Increases the Efficiency of Nitrogen Use by Irrigated Rice

Considering the importance of rice (Oryza sativa L.) for global food and its significant production in Brazil, strategies for its sustainable production are focused on technologies to increase productivity and decrease the use of chemical nitrogen fertilizers. An alternative for this is the use of plant growth-promoting bacteria that have proven to be efficient for increasing production and nutrient promotion in cereals. This study reports the use of coinoculation with Azospirillum brasilense and Pseudomonas fluorescens to inoculate irrigated rice through seed treatment (ST) with inoculant and seed inoculation in planting furrow technology (PFT) in four field experiments. The inoculation technologies increased rice yields in the presence of A. brasilense + P. fluorescens and with a reduction in mineral N (30 kg of N ha-1), equal to or greater when nitrogen fertilizer was present alone. Our results demonstrate that coinoculation with A. brasilense (strain Ab-V6) and P. fluorescens (strain CCTB03) increases the efficiency of N use from a mineral source in irrigated rice, with an increase of 37% in economic production (grains per unit of N applied), providing better agronomic performance of the crop.

Plant-microbe interactions ameliorate phosphate-mediated responses in the rhizosphere: a review

Phosphorus (P) is one of the essential minerals for many biochemical and physiological responses in all biota, especially in plants. P deficiency negatively affects plant performance such as root growth and metabolism and plant yield. Mutualistic interactions with the rhizosphere microbiome can assist plants in accessing the available P in soil and its uptake. Here, we provide a comprehensive overview of plant-microbe interactions that facilitate P uptake by the plant. We focus on the role of soil biodiversity in improved P uptake by the plant, especially under drought conditions. P-dependent responses are regulated by phosphate starvation response (PSR). PSR not only modulates the plant responses to P deficiency in abiotic stresses but also activates valuable soil microbes which provide accessible P. The drought-tolerant P-solubilizing bacteria are appropriate for P mobilization, which would be an eco-friendly manner to promote plant growth and tolerance, especially in extreme environments. This review summarizes plant-microbe interactions that improve P uptake by the plant and brings important insights into the ways to improve P cycling in arid and semi-arid ecosystems.