Nav: Home

Mapping a path to improved cassava production

April 18, 2016

For nearly a billion people around the world, cassava is a staple crop and a primary source of calories. The plant is easy to cultivate -- cuttings grow well on marginal land--and it is very tolerant of drought. For the U.S. Department of Energy, these traits and its starchy qualities make cassava of interest as a potential feedstock for biofuel production.

Though cassava is easy to cultivate, it is particularly vulnerable to plant pathogens, which can significantly reduce crop yields. To help improve breeding strategies for this root crop, a team led by researchers from University of California, Berkeley and including researchers from the DOE Joint Genome Institute (JGI), a DOE Office of Science User Facility, have described cassava's genetic diversity in an April 18, 2016 advanced online publication of the journal Nature Biotechnology. As cassava roots contain 20-40% starch that costs 15-30% less to produce per hectare than starch from corn, in many parts of the world, particularly Africa and Southeast Asia, it represents a strategic source of renewable energy--biomass from which ethanol is being produced for transportation fuels. With the help of genomics, researchers hope to apply advanced breeding strategies that can improve cassava's resistance to diseases and improve crop yields.

The cassava genome was sequenced under the aegis of the DOE JGI Community Science Program and Roche 454 Life Sciences. Since the draft sequence was released in 2009, researchers have improved it with additional data in order to develop a chromosome-scale sequence, in part in order to apply the information toward improved breeding strategies.

In the paper, the team, which included UC Berkeley postdoctoral fellows Jessen Bredeson and Jessica Lyons and DOE JGI's Simon Prochnik and Albert Wu, compared the cassava reference genome to the genomes of relatives castor bean (Ricinis communis), rubber tree (Hevea brasiliensis), Ceara rubber (Manihot glaziovii), and 53 cultivated and wild type cassava varieties from around the world. They found that the genetic diversity of cassava used in current breeding efforts has been greatly reduced in Africa, where viruses such as the cassava mosaic disease and the cassava brown streak disease have affected crop yields in many nations. They were able to detect the genetic signature of past cassava improvement programs going back to the 1930's, which interbred cassava and Ceara rubber, and the persistence of these Ceara rubber regions in elite cassava varieties suggests they confer desirable traits. They also elucidated relatedness between many cultivated cassava varieties, which can help breeders maximize genetic diversity in improvement programs.

"The variants and population structure described here are essential inputs for marker-assisted and genome selection-based approaches to improving disease resistance and yield for this staple crop," the team noted.

The cassava genome is available on the DOE JGI Plant Portal Phytozome at http://phytozome.jgi.doe.gov/.

Steve Rounsley of Dow AgroSciences spoke about cassava genomics at the DOE JGI's 2014 Genomics of Energy and Environment Meeting. Watch the video at http://bit.ly/JGI14UMRounsley. Co-author Chiedozie Egisi, formerly of Nigeria's National Root Crops Research Institute and now the project manager for the Next Generation Cassava Breeding program (NEXTGEN Cassava) at Cornell University, recently spoke about cassava breeding at the 2016 American Association for the Advancement of Science (AAAS) Annual Meeting. Watch his talk at http://bit.ly/Egesi2016AAAS.
-end-
Aside from Rounsley and Egesi, collaborators on this project included researchers at: International Institute of Tropical Agriculture (Nigeria), Koronivia Research Station (Fiji); CIRAD (Vanuatu); Mikocheni Agricultural Research Institute (Tanzania); Naliendele Agricultural Research Institute (Tanzania); Donald Danforth Plant Science Center; Cornell University, Monash University (Australia); International Institute of Tropical Agriculture (Kenya); and Dow AgroSciences.

The work was funded by the Bill & Melinda Gates Foundation, in part through Rounsley's work while at the University of Arizona, the UK Department for International Development (DFID), and the NEXTGEN Cassava Breeding project.

The U.S. Department of Energy Joint Genome Institute, User Facility of Lawrence Berkeley National Laboratory supported by the DOE Office of Science, is committed to advancing genomics in support of DOE missions related to clean energy generation and environmental characterization and cleanup. DOE JGI, headquartered in Walnut Creek, Calif., provides integrated high-throughput sequencing and computational analysis that enable systems-based scientific approaches to these challenges. Follow @doe_jgi on Twitter.

DOE's Office of Science is the largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.

DOE/Joint Genome Institute

Related Genetic Diversity Articles:

Rare genetic disorders: New approach uses RNA in search for genetic triggers
In about half of all patients with rare hereditary disorders, it is still unclear what position of the genome is responsible for their condition.
Major genetic study identifies 12 new genetic variants for ovarian cancer
A genetic trawl through the DNA of almost 100,000 people, including 17,000 patients with the most common type of ovarian cancer, has identified 12 new genetic variants that increase risk of developing the disease and confirmed the association of 18 of the previously published variants.
Use of fetal genetic sequencing increases the detection rate of genetic findings
In a study to be presented Thursday, Jan. 26, in the oral plenary session at 8 a.m.
Diversity without limits
Now, researchers at Temple and Oakland universities have completed a new tree of prokaryotic life calibrated to time, assembled from 11,784 species of bacteria.
Threatened by diversity
Psychologist Brenda Major identifies what may be a key factor in many white Americans' support for Donald Trump.
Genetic diversity crucial to Florida scrub-jay's survival
Legendary conservationist Aldo Leopold once advised: 'To keep every cog and wheel is the first precaution of intelligent tinkering.' For the endangered Florida scrub-jay, new research shows that saving every last grouping among its small and scattered remnant populations is vital to preserving genetic diversity -- and the long-term survival of the species.
Genetic diversity of enzymes alters metabolic individuality
Scientists from Tohoku University's Tohoku Medical Megabank Organization have published research about genetic diversity and metabolome in Scientific Reports.
Expanded prenatal genetic testing may increase detection of carrier status for potentially serious genetic conditions
In an analysis that included nearly 350,000 adults of diverse racial and ethnic background, expanded carrier screening for up to 94 severe or profound conditions may increase the detection of carrier status for a variety of potentially serious genetic conditions compared with current recommendations from professional societies, according to a study appearing in the Aug.
Fix for 3-billion-year-old genetic error could dramatically improve genetic sequencing
Researchers found a fix for a 3-billion-year-old glitch in one of the major carriers of information needed for life, RNA, which until now produced errors when making copies of genetic information.
Genetic diversity important for plant survival when nitrogen inputs increase
Genetic diversity is important for plant species to persist in Northern forests that experience human nitrogen inputs.

Related Genetic Diversity Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Anthropomorphic
Do animals grieve? Do they have language or consciousness? For a long time, scientists resisted the urge to look for human qualities in animals. This hour, TED speakers explore how that is changing. Guests include biological anthropologist Barbara King, dolphin researcher Denise Herzing, primatologist Frans de Waal, and ecologist Carl Safina.
Now Playing: Science for the People

#SB2 2019 Science Birthday Minisode: Mary Golda Ross
Our second annual Science Birthday is here, and this year we celebrate the wonderful Mary Golda Ross, born 9 August 1908. She died in 2008 at age 99, but left a lasting mark on the science of rocketry and space exploration as an early woman in engineering, and one of the first Native Americans in engineering. Join Rachelle and Bethany for this very special birthday minisode celebrating Mary and her achievements. Thanks to our Patreons who make this show possible! Read more about Mary G. Ross: Interview with Mary Ross on Lash Publications International, by Laurel Sheppard Meet Mary Golda...