You may think lupins are just a flower, but they are also rich in protein and can grow in various climates. However, they are not commonly cultivated as a crop due to their natural bitterness that makes them unpleasant to eat. This bitterness is caused by compounds called quinolizidine alkaloids (QAs) that are found in their seeds. However, not all lupins have this problem: in the 1930s, low QA (“sweet”) varieties of lupin were discovered. A recent report in Science Advances has found the gene responsible for making these lupins sweet by inhibiting the production of QAs. This discovery has great potential to increase the number of lupin varieties that are good to eat, which could have a significant impact on the world’s food supply.
The study identified a gene responsible for creating an enzyme called acetyltransferase. This enzyme helps to make QAs, affecting the bitterness of the lupin plant. The researchers used chemicals to alter the genes of a large number of bitter lupin seeds, a process called chemical mutagenesis. They then selected the seeds that had mutations in the acetyltransferase gene. These seeds grew into lupins that were sweet. With this technique, the researchers found that they were able to rapidly transform wild, bitter species of lupin into sweet ones.
This new advancement in breeding sweet lupins offers many potential advantages. Farmers can now produce a wider variety of edible lupins that are cost-effective and environmentally sustainable, serving as a great alternative to high-protein crops such as soybeans. Additionally, this discovery could pave the way for the domestication of other legumes containing QAs. The creation of new legume crops that are more nutritious and flavorful will ultimately benefit both human health and the environment.
This study was led by Davide Mancinotti, a postdoctoral researcher in the Department of Plant and Environmental Sciences at the University of Copenhagen in Frederiksberg, Denmark.
Managing Correspondent: Marwa Osman
Press Article: Discovery of ‘sweet lupin’ gene could lead to new high-protein crops (News from Science)
Original Journal Article: The causal mutation leading to sweetness in modern white lupin cultivars (Science Advances)