PGPR (Plant Growth-Promoting Rhizobacteria) are bacteria that inhabit the rhizosphere and colonize plant roots, positively influencing plant development. Among the bacterial genera considered PGPR can be found: Agrobacterium, Arthrobacter, Azospirillum, Azotobacter, Bacillus, Burkholderia,, Enterobacter, Flavobacterium, Klebsiella, Micrococcous, Pantoea, Pseudomonas and Rhizobium.

Microorganisms with these characteristics are capable of promoting plant growth by synthesizing metabolites or increasing the availability of different nutrients required for the plant metabolism. They can also protect the plant against diseases (for example, by inhibiting fungal growth).

At DARWIN, we characterize strains that, based on literature or origin, have PGPR potential. This can be applied to seeds, soil, or plant roots through seed coating, soil soaking, or foliar spray. This technique helps plants tolerate environmental stress such as drought, salinity, and heavy metals accumulation.

Problem

Plants do not always grow in an ideal environment and may face external conditions that negatively affect them, both physiologically and metabolically. These stress situations have a significant impact on the productivity and even the survival of the world’s major agricultural and forestry crops.

Hydric stress occurs when the demand for water exceeds the available amount in the soil. When plants experience water stress, they develop several molecular and morphological mechanisms, such as:

• Closure of stomata to minimize water loss through transpiration, limiting the entry of necessary carbon dioxide for photosynthesis.
• Reduction in photosynthesis, decreasing the amount of carbohydrates and energy available for growth and development.
• Reduction in growth and development: negatively affecting cell elongation, resulting in shorter plant height, smaller leaves, and inhibition of flower and fruit development.
• Development of survival strategies: accumulation of protective compounds such as abscisic acid, and synthesis of osmoprotective compounds to maintain cell turgor and survive.
• Decrease in nutrient uptake, leading to nutritional deficiencies and further weakening of plant health.

Due to these reasons, water stress significantly impacts crops, reducing fruits and grains production and quality.

Another type of stress is salinity stress, caused by excessive salt in soil or irrigation water, often due to poor irrigation management. Soil salinization is becoming a serious problem worldwide, affecting approximately 20% of the world’s cultivated lands, estimated at about 230 million hectares. This figure increases annually due to improper crop irrigation practices, excessive fertilization and plowing, and natural causes such as salt intrusion into coastal areas due to rising sea levels.

Solution

DARWIN’s solution is based on using microorganisms capable of promoting plant growth under stress conditions, without the need for traditional chemicals or fertilizers. These microorganisms facilitate the assimilation of macro and micronutrients and prevent the plant from producing ROS and other stress-related molecules.

PGPR helps to cultivate more efficiently with less water use, achieving equal or greater production compared to conventionally irrigated plants.

Completion Year: ongoing