About this Research Topic
Crop yields have historically increased thanks to breeding efforts and improved management. However, abiotic stressors such as high temperature, drought, salinity, heavy metal contamination, nutrient deficiency and elevated ozone, among others, can hinder efforts of breeders and other scientists to increase yields. In the last 40 years, great knowledge has been acquired about the physiological and molecular mechanisms around abiotic stress, resulting in new varieties that are tolerant to drought or high temperatures, among others. However, the role that microorganisms play in abiotic stress tolerance has been less studied due to the complexity of the symbiotic relations involved.
The beneficial role of microorganisms such as symbionts (mycorrhizae-forming fungi and rhizobial bacteria) and free-living microorganisms such as plant growth promotor rhizobacteria (PGPR) has been known for the past 50 years. The use of such microorganisms to increase plant tolerance to abiotic stress has been less studied due to complexities associated with isolation, and functional specificities among plant and microorganismal taxa. However, in the past 20 years, new microorganismal species and strains have shown to provide tolerance to certain abiotic stressors using several mechanisms. For example, there are specific Bradyrhizobium strains that confer drought and salt tolerance to common bean and soybeans, as they are able to maintain higher nitrogen fixation rates under these conditions. Certain mycorrhizal fungal species that through symbioses with specific crops, increase the root surface area of the host plant, thereby enhancing tolerance to drought and nutrient deficiencies. Certain PGPR strains have been also described that promote root growth, increasing plant tolerance to drought and other stressors.
This Research Topic aims to gather knowledge on molecular mechanisms in horticultural and row crops on how abiotic stress tolerance is mediated by microorganisms such as mycorrhizal fungi, rhizobia and PGPR. This Research Topic will only consider Original Research, Reviews, Systematic Reviews, and Methods papers that focus in the interaction between crop-microbe and abiotic stress, and have all of those components integrated. Specifically:
• Physiological response of crops and microorganisms to abiotic stress focusing on growth parameters under controlled and field environments.
• Molecular and biochemical mechanisms of the crop’s response that is triggered by the action of a specific microorganism.
• Studies reporting beneficial effects on crop growth and/or yield under stress conditions imparted by new microorganism species/strains, accompanied by physiologically relevant experiments that provide hypothesis-driven insights into the proposed mechanism.
• Specificity between crop cultivars and microorganism strains, and how this specificity can change under abiotic stress conditions.
• This Research Topic will also consider submissions that focus on the following abiotic stresses or combinations but is open to accept others if well justified: drought, salinity, flooding, high and low temperature, high and low light intensity, elevated carbon dioxide and ozone, nutrient deficiency and toxicity (including heavy metals).
This Research Topic will not consider manuscripts that focus in the following themes as they are focus of other Frontiers in Plant Science Research Topics or are outside the scope of the journal:
• Descriptive studies that do not advance understanding behind physiological processes
• Studies that only focus on the fitness of the microorganisms under different abiotic stresses.
• Studies that focus only in plant response to abiotic stress.
• Studies that focus in the microbiome or rhizosphere response to abiotic stress.
• Studies that although focusing in the interaction between plant, abiotic stress, and beneficial microorganisms do not demonstrate their rationale in important horticultural or row crops.
Keywords: Abiotic stress, plant growth promotor rhizobacteria, Rhizobia, crops
Important Note: All contributions to this Research Topic must be within the scope of the section and journal to which they are submitted, as defined in their mission statements. Frontiers reserves the right to guide an out-of-scope manuscript to a more suitable section or journal at any stage of peer review.