Sorghum millet is increasingly regarded as a crop of the future due to its ability to generate high biomass and thrive under harsh environmental conditions.
Some varieties even demonstrate enhanced sugar production in saline soils. In a recent study published in Scientific Reports (DOI: 10.1038/s41598-025-90432-2), an international team of researchers, including scientists from the Karlsruhe Institute of Technology (KIT), explored the mechanisms behind this salt-stress-induced sugar accumulation. Their investigation identified the gene switch SWEET13 as a key regulator that channels sugar into the grain. Through targeted breeding, this gene can be introduced into various sorghum millet lines to enhance their productivity and contribute to global food security, according press release.
As the global population continues to grow, so does the demand for food, raw materials, and energy. Increasing crop yields — particularly cereals — has become critical. However, climate change poses a growing challenge, with factors like heat, drought, and soil salinity increasingly threatening agricultural productivity. Rising sea levels have led to the salinization of once-fertile lands, exacerbating the pressure on crop systems. Sorghum millet, with its high biomass yield and ability to perform well in saline environments, presents a promising solution.
At KIT’s Joseph Gottlieb Kölreuter Institute for Plant Sciences (JKIP), the Molecular Cell Biology Division led by Professor Peter Nick has been studying sorghum millet for several years. As a member of the millet family within the sweet grass group, sorghum is known for its efficient photosynthesis process, which enables it to fix more carbon dioxide (CO₂) and produce greater biomass than many other crops. Prior research by Syrian scientist Dr. Adnan Kanbar at KIT led to the development of a new sweet sorghum variety that accumulates exceptionally high levels of sugar. This variety is well-suited for applications such as biofuel production, biogas generation, and the development of sustainable polymers.
Certain Varieties Produce More Sugar on Saline Soils
Further research shows that sorghum millet, an ancient crop plant from Sudan, thrives even in harsh conditions.
“Certain sorghum millet varieties not only cope well in a saline environment but react to increased salinity with the production of even more sugar,” says Nick. “Some of these varieties store the sugar in the stem, which makes them a candidate for energetic use, i.e. the production of biofuels. Other varieties store the sugar in the seeds, making them a valuable contribution to human nutrition.”
SWEET13 Gene Switch Directs Sucrose towards the Grains
A team of researchers, led by Dr. Eman Abuslima from Egypt, who completed her Ph.D. at the Molecular Cell Biology Division of KIT’s JKIP Institute, studied the salt stress-induced sugar accumulation and the various mechanisms of sugar storage in sorghum millet. Their findings revealed that the SWEET13 gene plays a key role in sugar transport within the plant.
“SWEET13 works like a switch: It determines that the sucrose formed by photosynthesis is directed into the plant’s grains,” explains Abuslima. The researchers found a particularly active type of SWEET13 in Razinieh, an ancient sorghum millet variety from Syria. This gene switch can be introgressed into other varieties by breeding. A polymerase chain reaction (PCR) helps to identify the breeding results with the correct variant as early as at the seedling stage. “This molecular knowledge can contribute to securing human nutrition in regions affected by soil salinization,” says Peter Nick. The Nile Delta, Bangladesh, but also southern parts of Italy are already struggling with the salt stress issue.
The scientists, among them researchers from KIT’s Institute of Applied Geosciences, Martin-Luther-University of Halle-Wittenberg, and research institutions from Egypt, Syria, and the USA, reported on their findings in the Scientific Reports journal.
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