Researchers have produced a high-quality chromosome-level genome of the faba bean (Vicia faba), one of the earliest domesticated crops.
The faba bean (Vicia faba) in Flora von Deutschland, Österreich und der Schweiz, 1885.
Faba bean was domesticated in the near East more than 10,000 years ago and its broad adaptability, value as a restorative crop in rotations and high nutritional density have propelled it to the status of a global crop grown on all continents except Antarctica.
Despite its global importance, no living wild progenitor species has been found.
Nonetheless, the finding of Neolithic charred seeds of wild faba bean points to pre-domestication use of this species by hunter-gatherers and possible domestication in the Levant.
Faba bean continues to be relevant in the 21st century as humanity strives to lower agricultural greenhouse gas emissions by replacing meat or milk protein with plant-based alternatives.
It is the highest yielding of all grain legumes and has a favorable protein content (approximately 29%) compared with other cool-season pulses such as pea, lentil and chickpea, making it a suitable candidate to meet challenging projected future protein demands.
Furthermore, the high biological nitrogen fixation rates of faba bean and the long duration of nectar-rich, pollinator-friendly flowers provide important ecosystem services, which means that cultivation of faba bean is increasingly seen as key for sustainable intensification strategies.
“Substantial progress has been made in faba bean genomics and pre-breeding research,” said University of Reading’s Professor Donal O’Sullivan and colleagues.
“However, the lack of a reference genome sequence greatly complicated the studies, and improved faba bean genomic resources are urgently needed to accelerate crop improvement.”
According to the team, the faba bean is an isolated species and does not hybridize with others in the genus Vicia, effectively barring the use of wild relatives in faba bean breeding.
Its genome is at least 13 billion bases long — more than four times the size of the human genome.
The authors also searched for genes involved in seed size and looked at the color of the hilum — the scar left when a bean detaches from the pod — to see if they could find the genes that determine this distinctive feature.
“Having shown that we can quickly pinpoint genes controlling these visible seed traits, work is already underway to locate and identify precise genetic differences that control hidden seed characteristics that determine its nutritional value,” Professor O’Sullivan said.
“We want to produce beans that are higher in essential amino acids as well as lower in antinutrients, such as phytate, which binds micronutrients and reduces absorption.”
“Having the genome sequence will accelerate this process considerably.”
The team’s results appear in the journal Nature.
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M. Jayakodi et al. The giant diploid faba genome unlocks variation in a global protein crop. Nature, published online March 8, 2023; doi: 10.1038/s41586-023-05791-5
Source : Breaking Science News