“For us, it means it gives you longer reads, longer pieces — so that you’re assembling a jigsaw puzzle out of a million pieces, instead of out of 25 million smaller pieces,” Gmitter said. “What’s most important is to have this high-quality, original haploid reference sequence. And we did that.”

The team that worked to obtain the gene sequence for the Clementine mandarin included scientists from the University of Florida, Italy, Brazil, France and Spain and the U.S. Department of Energy’s Joint Genome Institute (JGI). Simultaneously, work was being done to obtain the diploid sweet orange sequence by scientists from UF, JGI, Georgia Tech and 454 Life Sciences, a Roche Company.

“I’m proud that our scientists helped lead the way in this world-class research,” said Mark McLellan, IFAS’ dean for research. “We believe having these genome sequences will greatly help the state’s citrus industry, as well as citrus growers around the world.”

Since its discovery in Florida in 2005, greening has caused havoc in the citrus industry. It has wiped out some citrus crops in Asia, Africa, the Arabian Peninsula and Brazil. Greening slowly weakens and kills all types of citrus trees, while rendering fruit malformed and discolored.

But while the two new genome sequences may provide just the tool scientists need to help them solve the greening crisis, Gmitter said having them is “really much, much, bigger than that.”

Some of the possibilities, he said, include citrus trees with more beautiful fruit, better disease resistance, more phytonutrients, and tolerance for salt, bad soil or extreme temperatures.

California citrus grower Earl Rutz, vice-chairman of that state’s Citrus Research Board, praised what he called “the first of its kind as a true international collaboration with benefits for all in the citrus research community.”

Peter McClure, a Florida citrus grower and former chairman of the Florida Citrus Research Production Advisory Council, called the genome sequences great news for the citrus industry, which has often battled serious foes in weather and disease.

“From a global perspective, unless sustainable solutions are found citrus will also become extinct for many subsistence level farmers around the globe that utilize citrus as an important fresh fruit nutrient source as well as an important high-value cash crop,” McClure said. “HLB (greening) is an extremely complicated disease problem, and sequencing the citrus genome is a real breakthrough towards solving HLB. There is still a lot of work to do, but this gets us closer.”

Ted Batkin, president of the California Citrus Research Board, praised the work, saying the new information could allow breeding of new varieties specific to geographic regions.

“The importance of a complete genome sequence cannot be stressed enough,” he said.