This image shows a gene order map (created using GENESPACE) that compares genome assemblies among related plant species. The horizontal white lines represent chromosomes, and the colored braids that link them show conserved blocks of genes. Credit: Adam Healey and John Lovell/HudsonAlpha
Key points:
- Sugarcane’s genome has been difficult to accurately sequence due to its size and complexity with many chromosome copies.
- Researchers combined multiple genetic sequencing techniques to create a highly accurate reference genome for sugarcane that shows how genes influence different traits.
- The genome mapping revealed that genes responsible for resistance to the fungal pathogen brown rust are in only one genome location.
Sugarcane’s complicated genetics have made it the last major crop without a complete and highly accurate genome—but that is not the case any longer.
Now that scientists have successfully mapped sugarcane’s genetic code, they can improve understanding of the genes involved in sugar production and disease resistance.
Sugarcane’s genome is large and contains more copies of chromosome than a typical plant—a feature called polyploidy. To accurately sequence this complex genome, researchers combined multiple genetic sequencing techniques, including a new method called PacBio HiFi sequencing that can determine the sequence of longer sections of DNA.
Researchers created a complete “reference genome”, which allows them to more easily understand how each gene influences different sugarcane traits. Importantly, this study—in published in Nature—showed which genes are highly expressed during sugar production and which are important for disease resistance.
“When we sequenced the genome, we were able to fill a gap in the genetic sequence around brown rust disease,” said first author Adam Healey, researcher at HudsonAlpha. “There are hundreds of thousands of genes in the sugarcane genome, but it’s only two genes working together, that protect the plant from this pathogen."
In addition to determining the genetic basis of disease resistance, the team can also use the complete sequence to trace which genes control traits linked to improved sugarcane production. This knowledge has implications for both agriculture and bioenergy solutions.
“With a better understanding of sugarcane genetics, we can better understand and control the plant genotypes needed to produce the sugars and bagasse-derived intermediates we need for sustainable sugarcane conversion technologies at a scale relevant to the bioeconomy,” explained Blake Simmons of the Lawrence Berkeley National Laboratory.