In a paper published online Tuesday, a group of scientists in the U.S. and Europe has shown that dried citrus can be used to make a new strain of genetically engineered citrus trees that grow faster and yield more fruit than their genetically modified counterparts.
They also reported a novel approach for cultivating the citrus, using an agricultural yeast called Brettanomyces spp.
to grow the trees.
They said that the new strain is more resistant to drought and pests than the genetically engineered ones.
The researchers, led by David S. Stahl, a chemical engineer at the University of Pennsylvania, are not disclosing their work publicly because of a federal research-recruitment secrecy law.
Stahls group first began experimenting with Brettanomys spp in 2009.
Brettanomss strains are usually produced by anaerobic bacteria, such as Pseudomonas aeruginosa, that is tolerant to the acidity of water.
The yeast’s ability to tolerate that is critical in making the fruit attractive to farmers.
Brettans strains also are prone to disease, and when harvested, they produce a large amount of a toxic chemical called acetic acid.
The chemical is used to kill many insects that eat the fruit.
Brett’s genes are also linked to a type of fungus that produces toxins that can harm fruit.
In the latest study, the scientists found that using Brettanams yeast to grow Brettanamys spa.
would produce a strain that could withstand drought conditions and would produce more fruit per hectare than its genetically engineered brethren.
They were able to use a chemical called aminopyran sulfate to make the new strains more resistant than Brettanami spp., which use the enzyme pyruvate dehydrogenase, to drought.
This allowed the researchers to increase the amount of acetic acetic acids produced by the Brettanameys strain.
The new strain could produce about a third more acetic aces per hectate, the researchers wrote.
This is the first time researchers have grown a genetically engineered fruit that was resistant to a variety of pests, they said.
“This shows that there are other possibilities for producing resistant strains, and that there is still a way to go,” said Stahl.
They added that the researchers had found that the genetic information of the Brettanolomyces strain was similar to that of the common Brettanaminaceae strain, but that the strain used in the new study had a “new, more specific” gene.
This was the first known example of a new genetic trait in a cultivated Brettanaceae strain that would be passed on to its descendants, the team said.
Brettanolomys is a family of Brettanomas, which is a genus of yeast that grows naturally in many temperate climates.
The scientists are now working on breeding this Brettanamyces strain to produce more resistant varieties.
They are also trying to improve the performance of the engineered Brettanamlys strain and find ways to improve its growth and yield.