Natural extracts boost drought resistance in lettuce and broccoli

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A team from the Universitat Politècnica de València (UPV), the Spanish National Research Council (CSIC) and the Universitat Jaume I of Castelló, in collaboration with the company Caldic Ibérica, has developed a product based on four natural extracts from different plants and algae that stimulates the resistance of lettuce to salinity and drought, a growing problem in Mediterranean agriculture.

The study, led by the Institute of Molecular and Cellular Biology of Plants (IBMCP), a joint center of the UPV and the CSIC, and recently published in the Journal of Integrative Plant Biology, asserts that the product, called CalBio, can be used in both conventional and organic farming, as it does not contain synthetic chemical products and therefore complies with the regulations.

Research shows that the application of this product (solid and granular particles) in the irrigation system increases the yield of the lettuce crop under normal conditions, but especially on saline soils. The substance applied to the plant induces the production of plant hormones called "cytokinins," which cause the plant to increase its defenses in agricultural soils with high salinity.

Product considered a biostimulant

José Miguel Mulet, IBMCP researcher and coordinator of the study, states, "Since these are products of natural origin, the approval process is easier because they are considered biostimulants, so the transfer of these results to farmers will be much quicker and easier.

"In addition, the efficacy of CalBio is proven and its molecular mechanism is known, which is not the case with many products currently on the market. We have also found that the product is most effective when used in combination with micro-organisms that occur naturally in plant roots.

"These are bacteria from the PGPB family, plant growth promoting bacteria. These micro-organisms live in the soil and form a symbiosis with plant roots. The study shows that the bacteria belong to the Bacillus megaterium strain," explains Mulet.

The research is the result of a project from the 2022 Call for Collaborative Challenges of the Ministry of Science, Innovation and Universities (Next Generation), with the company Caldic Ibérica, a wholesaler of chemical products for industry, food and pharmaceuticals. Vicente Arbona and Miguel González-Guzmán, professors at the Universitat Jaume I in Castelló, are also involved in the project.

The team of scientists has also confirmed that the product, made from natural plant and algae extracts, also works on broccoli, in a study just published in the journal Scientia Horticulturae. What is unique about this experiment is that the product is effective without the cooperation of PGPB bacteria, as broccoli and all Brassica vegetables do not normally form a symbiosis in the roots.

They are also evaluating its performance on tomato, avocado, onion, pepper and eggplant. All field trials are being carried out at AVA-ASAJA's experimental plot in Polinyà del Xúquer (Valencia).

More information: Patricia Benito et al, The combination of a microbial and a non‐microbial biostimulant increases yield in lettuce (Lactuca sativa) under salt stress conditions by up‐regulating cytokinin biosynthesis, Journal of Integrative Plant Biology (2024). DOI: 10.1111/jipb.13755

Carlos Montesinos et al, Field evaluation and characterization of a novel biostimulant for broccoli (Brassica oleracea var. italica) cultivation under drought and salt stress which increases antioxidant, glucosinolate and phytohormone content, Scientia Horticulturae (2024). DOI: 10.1016/j.scienta.2024.113584

Provided by Technical University of Valencia