From Bitter to Sweet Lupins: The Rising Potential of High-Protein Crops

The Genetic Journey of Lupin Domestication

- A collaboration between Traitomic and the University of Copenhagen

Lupins, a high-protein and stress-tolerant crop that has the potential to compete with soybean import in Europe, generally produce bitter compounds known as quinolizidine alkaloids (QA). "Sweet" varieties of lupins have existed since the 1930s, but are genetically unstable and are less disease resistant than bitter varieties. Dr. Fernando Geu-Flores' research group at the University of Copenhagen has successfully identified a 'sweet' lupin gene for the first time, which can be used to eliminate the production of QAs in bitter varieties. Using Traitomic's FIND-IT technology, Davide Mancinotti et al, were able to quickly validate a genetic target in their plant pathway discovery approach by generating a sweet lupin mutant. This research was published in the latest edition of Science Advances and has the potential to pave the way for the domestication of sweet lupins in Europe.

Validating the ''sweetness gene'' in lupins

Mancinotti et al started by analysing many varieties of white lupin and testing their respective alkaloid levels. They were able to correlate four SNPs in the acetyltransferase gene (AT) to the level of alkaloid production. The next step was to identify if these genetic variations can cause sweetness in native bitter lupins.

"We then used FIND-IT technology to isolate an early stop codon mutant in the AT gene (AT_KO, TGG to TAG at codon 169)"

‍

Gene knockouts of the AT gene were required to validate the function of the identified gene. Traitomic created a library with over 100,000 narrow-leafed lupin seeds in order to screen for the exact early stop codon genetic variants. After testing both the homozygous and heterozygous knockout, the genetic variants showed to have a 99% reduced alkaloid content in the homozygous line.

Lupins will play an important role in the future

The EU has been pushing for less import of soybeans and is therefore trying to promote the production of other high protein crops in Europe. As lupins are suited to growing in northern climates, domesticating lupins could prove to be a major step forward towards a more sustainable world.

Plant breeding without the need for genetic modification

"The use of non-GMO techniques as exemplified here is particularly attractive for legume crop candidates for which transformation protocols are not available and those that are grown in geopolitical areas with restrictive GMO regulation."

‍

Wallace Cowling, Professor at the university of Western Australia who was not involved in this research, mentioned that ''this paper is a brilliant example of how modern technology can improve outcomes from plant breeding without the need for genetic modification''. Chemical mutagenesis is exempt from EU genetic modification regulations, making it a great technology to accelerate research in plant breeding. It also offers a solution to crops that are difficult to genetically modify, such as lupin.

‍