An international team of researchers led by the University of Arizona has sequenced the complete genome of African rice.
The genetic information will enhance scientists' and agriculturalists' understanding of the growing patterns of African rice, as well as enable the development of new rice varieties that are better able to cope with increasing environmental stressors to help solve global hunger challenges.
The O. glaberrima genome (CG14 v1).
Concentric circles show structural, functional and evolutionary aspects of the genome: A, chromosome number; B, heat map view of genes; C, repeat (RNA and DNA TEs without MITEs) density in 200-kb windows (red, average +1 s.d.; blue, average −1 s.d.; yellow, gene and repeat density between red and blue); and D paralogous relationships between O. glaberrima chromosomes.
The paper, "The genome sequence of African rice (Oryza glaberrima) and evidence for independent domestication," was published online in Nature Genetics on Sunday.
The effort to sequence the African rice genome was led by Rod A. Wing, director of the Arizona Genomics Institute at the UA and the Bud Antle Endowed Chair in the School of Plant Sciences in the UA College of Agriculture and Life Sciences, with a joint appointment in the UA Department of Ecology and Evolutionary Biology.
"Rice feeds half the world, making it the most important food crop," Wing said. "Rice will play a key role in helping to solve what we call the 9 billion-people question."
The 9 billion-people question refers to predictions that the world's population will increase to more than 9 billion people – many of whom will live in areas where access to food is extremely scarce – by the year 2050. The question lies in how to grow enough food to feed the world's population and prevent the host of health, economic and social problems associated with hunger and malnutrition.
Now, with the completely sequenced African rice genome, scientists and agriculturalists can search for ways to cross Asian and African species to develop new varieties of rice with the high-yield traits of Asian rice and the hardiness of African rice.
"African rice is once more at the forefront of cultivation strategies that aim to confront climate change and food availability challenges," said Judith Carney, a professor of geography at the Institute of the Environment and Sustainability at the University of California, Berkeley, and author of "Black Rice." The book describes the historical importance of African rice, which was brought to the United States during the period of transatlantic slavery.
Carney is also a co-author on the Nature Genetics paper, and her book served as one of the inspirations behind sequencing the African rice genome.
"We're merging disciplines to solve the 9 billion-people question," Wing said.
Although it is currently cultivated in only a handful of locations around the world, African rice is hardier and more resistant to environmental stress in West African environments than Asian varieties, Wing said.
African rice already has been crossed with Asian rice to produce new varieties under a group known as NERICA, which stands for New Rice for Africa.
The African rice genome is especially important because many of the genes code for traits that make African rice resistant to environmental stress, such as long periods of drought, high salinity in the soils and flooding.
"Now that we have a precise knowledge of the genome we can identify these traits more easily and move genes more rapidly through conventional breeding methods, or through genetic modification techniques," noted Wing, who is also a member of the UA's BIO5 Institute and holds the Axa Endowed Chair of Genome Biology and Evolutionary Genomics at the International Rice Research Institute. "The idea is to create a super-rice that will be higher yielding but will have less of an environmental impact – such as varieties that require less water, fertilizer and pesticides."
Hardy, high-yield crops will become increasingly vital for human survival as the world faces the environmental effects of climate change and an ever-growing global population, he added.
Wing's research group specializes in developing what geneticists call physical maps, a tool that enables scientists to understand the structure of the genome. His group developed the physical maps for Asian rice and donated it to the Rice Genome Project, making sequencing of that complete genome possible.
Much of the evolutionary analysis of the genome was performed by Muhua Wang, a UA plant sciences doctoral candidate, and by Carlos Machado of the University of Maryland. Yeisoo Yu, a research associate professor in Wing's research group at the Arizona Genomics Institute, led the sequencing effort.
In analyzing the 33,000 genes that make up the African rice genome, the researchers discovered that during the process of domestication, Africans and Asians independently selected for many of the same genetic traits in the two species, such as higher nutrition and traits that make harvesting the crop easier.
Additionally, the sequenced genome helps resolve questions about whether African rice originally was domesticated in one region or in several locations across Africa. By comparing the genome with what is known about the genetic structure of wild varieties, Wing and his team found that it's most similar to a population of wild rice species found in one location along the Niger River in Mali. "Our data supports the hypothesis that the domestication of African rice was centric in this region of Africa," Wing said.
From 1998 to 2005, Wing led the U.S. effort to help sequence the genome of Asian rice, which is the only other domesticated rice species. Those results were published in the journal Nature in 2005, and have since enabled the discovery of hundreds of agriculturally important genes, including genes that code for faster breeding cycles and the ability for the plant to survive for up to two weeks underwater during periods of flooding.
Wing's research group is now focusing on sequencing and analyzing the genomes of the wild relatives of African and Asian rice. "By understanding the entire genus at a genome level we have a whole new pool of genetic variation that can be used to combat pests and plant pathogens," Wing explained.
One example, he said, would be adding disease resistance genes from all of the wild rice varieties to a species of cultivated rice, creating a new super-crop that is resistant to diseases and pests.
Wing is also working with Quifa Zhang from Huazhong Agricultural University in Wuhan, China, to create a set of super-crop science and technology centers around the world, where focused and coordinated efforts could help solve the 9 billion-people question. "We really only have about 25 years to solve this problem, and if we're always competing with each other it's not going to work," he said.
"After decades of promoting high-yielding Asian varieties, the emphasis now is on developing types that combine the former's higher yields with glaberrima’s tolerance of environmental stress," Carney noted.
In November, Wing and his collaborators will celebrate the 10th anniversary of the completion of the Asian rice genome and the new completion of the African rice genome at the 12th International Symposium on Rice Functional Genomics, a conference that will be held in Tucson, Arizona.
Research paper: http://www.nature.com/ng/journal/vaop/ncurrent/full/ng.3044.html
Rod A. Wing
UA Arizona Genomics Institute
University Relations, Communications
Shelley Littin | University of Arizona
A Map of the Cell’s Power Station
18.08.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau
On the way to developing a new active ingredient against chronic infections
18.08.2017 | Deutsches Zentrum für Infektionsforschung
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
18.08.2017 | Life Sciences
18.08.2017 | Physics and Astronomy
18.08.2017 | Materials Sciences