Climate-resilient crops: Experts spotlight sorghum for sustainable farming

A three-part research project at the Center for Research in Agricultural Genomics (CRAG), Spain, has made significant headway in understanding the molecular mechanisms of sorghum to advance its breeding. The world’s fifth most cultivated cereal is particularly important in arid and semi-arid regions, due to its natural resistance to drought and high temperatures. 

The CRAG researchers have identified the molecular mechanisms responsible for drought resistance in sorghum and developed tools that could be used in biotechnological applications.

This could improve the crop’s adaptability to stress conditions and enhance its handling in the laboratory for future breeding processes.

“Our goal was to equip the sorghum community with not only cutting-edge molecular tools to accelerate sorghum breeding but also some key target genes essential for developing drought-resistant crops,” explains Juan Fontanet-Manzaneque, lead author of both studies.

Socio-economic and political implications

Sorghum is increasingly considered a crucial crop for climate change adaptation due to its tolerance to high temperatures and drought, especially compared to maize, which is the most widely cultivated cereal in Europe and is highly susceptible to water stress.

From a nutritional standpoint, sorghum bran has higher levels of essential amino acids and minerals needed for human health and development than whole grain or dehulled sorghum flour. It also contains higher levels of crude protein, fat, and fiber than whole and dehulled grain.

Studies show that sorghum’s importance in Europe is expected to increase because of climate change. The expansion of sorghum cultivation in Spain could also create new economic opportunities for farmers, reducing dependence on imports and boosting local agricultural production.

In Catalonia, more than 100,000 tons of sorghum were produced in 2023, more than 90% of which was destined for animal feed.

The rising demand for sorghum, which increased by around 6% in 2024, highlights its potential to improve nutrition, especially when research is leading to new varieties of sorghum.Furthermore, sorghum is a naturally gluten-free cereal, a particularly relevant characteristic in the food industry. Its adaptability and high nutritional value make it a key crop for improving food security.

The rising demand for sorghum for human consumption, which increased by around 6% in 2024, highlights its potential to improve nutrition, especially when research is leading to new varieties of sorghum.

Two decades of research

For the last 20 years, the research group led by Ana Caño-Delgado has been dedicated to the study of this cereal and has received numerous grants, including funding from the European Research Council. In the last six months, the group has published three scientific articles of significant importance to the sector.

In the first of these three studies, published in the Plant Biotechnology Journal, the research team identified that mutations in the protein Sorghum bicolor brassinosteroid receptor, SbBRI1, confer drought tolerance by altering phenylpropanoid metabolism. 

This finding highlights a molecular mechanism for enhancing drought resistance in sorghum. It is also relevant for other essential crops, such as maize, wheat, and rice, which also contain brassinosteroid signaling pathways.

A second work, published in The Plant Journal, uncovered a significant advancement in sorghum biotechnology — an efficient transformation method using a ternary vector system combined with morphogenic regulators.

Previous tools and methods were not effective enough for studying certain varieties of sorghum, posing a significant challenge for scientists and breeders.

This new protocol solves this problem by allowing for highly efficient transformation using Agrobacterium tumefaciens and enabling the application of new breeding techniques like gene editing to accelerate crop improvement.

This technology provides a useful tool for creating and studying mutants of interest with a very high efficiency in the transformation of recalcitrant sorghum (varieties that are resistant to genetic transformation), reaching two-fold increase in the transformation efficiency.

The third study, which is published in the New Phytologist Journal, characterizes the role of SbBRI1 in root development, specifically in the meristem region, linking BRI1 to cell wall metabolism and demonstrating that the sorghum SbBRI1 protein plays functionally conserved roles in plant growth and development. 

The root development is crucial for the overall growth and health of the plant and plays a role in how the plant responds to environmental stressors.

The research findings may improve the crop’s adaptability to stress conditions and enhance its handling in the laboratory for future breeding processes.Andrés Rico-Medina, the study’s first author, explains the implemented technique: “We adapted the staining and imaging protocols that are used in model plants like Arabidopsis to be useful for studies in Sorghum.”

“This adaptation serves to bridge the gap between laboratory-based drought studies and a more agronomic context, thereby facilitating the practical application of these scientific advancements.”

Sorghum’s growing importance

Sorghum is increasingly recognized as a staple food in many parts of the world, including outside Africa, where it has been cultivated for centuries, due to its multiple nutritional benefits and resistance to adverse climatic conditions.

In Europe, sorghum cultivation is on the rise and is being promoted as an alternative for crop rotation, especially in regions prone to water scarcity.

The EU is actively promoting sorghum cultivation as a climate-resilient crop, with a 57% increase in total sorghum production during the last decade. France, in particular, is at the forefront of this trend, with 103,000 hectares dedicated to grain sorghum cultivation last year.

Meanwhile, Spain is a major importer of sorghum in Europe, mainly for animal feed but with prospects for human food in the future. In 2020, 158,000 tons were imported into Spain, so an increase in its cultivation in the territory could reduce dependence on imports.

For reference, Spain imported 303,000 tons of barley in the past six months, making it the third most imported crop.

“This research represents a significant opportunity for CRAG to establish technology transfer projects, to encourage public-private collaboration, and to highlight the excellent work of our researchers,” concludes Caño-Delgado.

Previous research spotlighted millet, an underutilized but nutrient-dense and climate-resilient crop, as a solution for food insecurity.