Microalgae-based biostimulants challenges and opportunities for sustainable agriculture

The agricultural sector faces an urgent challenge in addressing the issues posed by climate change. In addition, projections suggest that by 2050 the demand for food will be about 50% higher than current global production. More will need to be produced, but with an emphasis on greater sustainability. In this scenario, plant biostimulants have gained increasing popularity in recent decades. These products can improve nutrient uptake, yield quality and adaptation to abiotic stresses in crops, reducing the environmental footprint of ordinary agricultural practices. Only recently the scientific community has shown interest in using microalgae as a starting matrix for the development of new and more sustainable biostimulant products. Unlike biostimulants sourced from macroalgae biomass, the use of microalgae extracts is still in its early stage. This review outlines the current knowledge regarding the use of microalgae extracts in agriculture, identifying the key gaps to be addressed.