Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Retracing Citrus’ Earliest Roots to Find Clues for Healthier Future


That orange you’re enjoying may have been grown in Florida, but its deepest ancestral roots stretch back more than 5 million years, all the way to two wild citrus species from Southeast Asia.

University of Florida scientists led an international research team that analyzed the genome sequences of 10 diverse citrus varieties for the first time.

Their findings, published online Sunday by the journal Nature Biotechnology, could help the citrus industry find and deploy genes for resistance to citrus greening, a bacterial infection devastating crops in North America.

Fred Gmitter, a UF Institute of Food and Agricultural Sciences faculty member, led the team of researchers from the United States, France, Italy, Spain and Brazil as part of a decade-long project to sequence and understand citrus genomes.

... more about:
»Citrus »crops »genes »genomes »resistance »sequences »species »sweet »varieties

They analyzed and compared the genome sequences of sweet and sour oranges, along with several important mandarin and pummelo varieties. By understanding the relationships between the various cultivated species they describe as having “very narrow genetic diversity,” the researchers hope to enable genetic modifications and traditional breeding, which could lead to crops more resistant to disease and environmental stress, as well as better flavor and health-promoting benefits.

“Citrus has incestuous genes - nothing is pure,” said Gmitter, who is based at UF’s Citrus Research and Education Center in Lake Alfred. “Now that we understand the genetic structure of sweet orange, for example, we can imagine reproducing early citrus domestication using modern breeding techniques that could draw from a broader pool of natural variation and resistance.”

New citrus trees are almost always produced by grafting, a method of propagation that binds the fruit bearing part of one tree to the root system of another. That produces trees that more quickly bear genetically identical, uniform, high quality fruit. But because of that uniformity, if one tree is susceptible to disease, they all are.

Citrus is the world’s most widely cultivated fruit crop. In Florida, it is a $9 billion industry, employing 75,000. But it is under attack from a tiny bug, the Asian citrus psyllid, which sucks on leaf sap and leaves behind the citrus greening bacteria.

The disease, which renders fruit unsuitable for sale and eventually kills trees, could wipe out the industry in the next decade if a viable treatment is not found.

UF/IFAS researchers have attempted everything from trying to eradicate the psyllid to breeding citrus rootstocks that show better greening resistance. Current control methods include removing and destroying infected trees, controlling the psyllid, and providing additional nutrition in an attempt to keep infected trees productive.

Citrus was first domesticated in Southeast Asia thousands of years ago before spreading throughout Asia, Europe, and the Americas via trade.

One of the two wild species, Citrus maxima, gave rise to today’s cultivated pummelo, the largest citrus fruit, which can often weigh 2 to 4 pounds or more. The small, easily peeled mandarins were, in contrast, found to be genetic mixes of a second species (Citrus reticulata, the ancestral mandarin species) and pummelo. Sweet orange, the world’s most widely grown citrus variety, was found to be a complex hybrid, with mixed bits and pieces of the mandarin and pummelo genomes. Seville, or sour orange, commonly used in marmalade, is a simple hybrid between the two ancestral species.

The U.S. Department of Energy’s Joint Genome Institute, Genoscope in France, the Institute for Genomic Applications in Italy, and 454 Life Sciences, a Roche company, contributed to the citrus genome project.

Kimberly Moore Wilmoth | newswise
Further information:

Further reports about: Citrus crops genes genomes resistance sequences species sweet varieties

More articles from Life Sciences:

nachricht Two decades of training students and experts in tracking infectious disease
27.11.2015 | Hochschule für Angewandte Wissenschaften Hamburg

nachricht Increased carbon dioxide enhances plankton growth, opposite of what was expected
27.11.2015 | Bigelow Laboratory for Ocean Sciences

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Climate study finds evidence of global shift in the 1980s

Planet Earth experienced a global climate shift in the late 1980s on an unprecedented scale, fuelled by anthropogenic warming and a volcanic eruption, according to new research published this week.

Scientists say that a major step change, or ‘regime shift’, in the Earth’s biophysical systems, from the upper atmosphere to the depths of the ocean and from...

Im Focus: Innovative Photovoltaics – from the Lab to the Façade

Fraunhofer ISE Demonstrates New Cell and Module Technologies on its Outer Building Façade

The Fraunhofer Institute for Solar Energy Systems ISE has installed 70 photovoltaic modules on the outer façade of one of its lab buildings. The modules were...

Im Focus: Lactate for Brain Energy

Nerve cells cover their high energy demand with glucose and lactate. Scientists of the University of Zurich now provide new support for this. They show for the first time in the intact mouse brain evidence for an exchange of lactate between different brain cells. With this study they were able to confirm a 20-year old hypothesis.

In comparison to other organs, the human brain has the highest energy requirements. The supply of energy for nerve cells and the particular role of lactic acid...

Im Focus: Laser process simulation available as app for first time

In laser material processing, the simulation of processes has made great strides over the past few years. Today, the software can predict relatively well what will happen on the workpiece. Unfortunately, it is also highly complex and requires a lot of computing time. Thanks to clever simplification, experts from Fraunhofer ILT are now able to offer the first-ever simulation software that calculates processes in real time and also runs on tablet computers and smartphones. The fast software enables users to do without expensive experiments and to find optimum process parameters even more effectively.

Before now, the reliable simulation of laser processes was a job for experts. Armed with sophisticated software packages and after many hours on computer...

Im Focus: Quantum Simulation: A Better Understanding of Magnetism

Heidelberg physicists use ultracold atoms to imitate the behaviour of electrons in a solid

Researchers at Heidelberg University have devised a new way to study the phenomenon of magnetism. Using ultracold atoms at near absolute zero, they prepared a...

All Focus news of the innovation-report >>>



Event News

Fraunhofer’s Urban Futures Conference: 2 days in the city of the future

25.11.2015 | Event News

Gluten oder nicht Gluten? Überempfindlichkeit auf Weizen kann unterschiedliche Ursachen haben

17.11.2015 | Event News

Art Collection Deutsche Börse zeigt Ausstellung „Traces of Disorder“

21.10.2015 | Event News

Latest News

Siemens to supply 126 megawatts to onshore wind power plants in Scotland

27.11.2015 | Press release

Two decades of training students and experts in tracking infectious disease

27.11.2015 | Life Sciences

Coming to a monitor near you: A defect-free, molecule-thick film

27.11.2015 | Materials Sciences

More VideoLinks >>>