Sugarcane's complicated genetics made it the last major crop without a complete and highly accurate genome. Scientists from France, Australia, Czech Republic, and the United States led by the U.S. Department of Energy Joint Genome Institute (JGI) have developed and combined multiple techniques to successfully map out sugarcane's genetic code.
Sugarcane's genome is large and contains more copies of chromosomes than a typical plant, a feature called polyploidy. Sugarcane has about 10 billion base pairs, whereas the human genome has about 3 billion. Many sections of sugarcane's DNA are identical both within and across different chromosomes. That makes it a challenge to correctly reassemble all the small segments of DNA while reconstructing the full genetic blueprint. Researchers solved the puzzle by combining multiple genetic sequencing techniques, including a newly developed method known as PacBio HiFi sequencing that can accurately determine the sequence of longer sections of DNA.
A complete reference genome makes it easier to study sugarcane, enabling researchers to compare its genes and pathways with those in other well-studied crops such as sorghum or other biofuel crops of interest, like switchgrass and Miscanthus. With the map, the scientists were able to verify the specific location that provides resistance to the impactful brown rust disease that, unchecked, can devastate a sugar crop. In the future, researchers can also use the genetic sequence to better understand the many genes involved in sugar production.
(Source: Crop Biotech Update, International Service for Acquisition of Agri-Biotech Applications. www.isaaa.org)
