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LinkedInPosts Tagged: genetic
Shedding New Light on Honey Bee Chromosomes
Honey bee geneticists with long ties to UC Davis are putting together those missing pieces of the puzzle involving bee chromosomes. Newly published research by a team of Germany-based honey bee geneticists, collaborating with Robert Eugene (“Rob”) Page Jr., of Arizona State...
"The honey bee genome,” Robert Page Jr. explained, “is composed of about 15,000 genes, each of which operates within a complex network of genes, doing its small, or large, share of work in building the bee, keeping its internal functions operating, or helping it function and behave in its environment. (Photo by Kathy Keatley Garvey)
Honey bee geneticist Robert Page Jr. (left) with colleagues: bee breeder-geneticist Kim Fondrk of UC Davis, and Martin Beye, former postdoctoral fellow in the Page lab and now a professor at the University of Düsseldorf, Germany.
There's a Genetic Component to the Host Choice of This Malaria Mosquito
A mosquito that feeds on both humans and cattle and is the primary vector of malaria in east Africa is making headlines. And well it should. Research led by UC Davis medical entomologists and published in the Sept. 15 edition of PLOS Genetics, indicates "a genetic component" to the blood-feeding...
Villagers and cattle along the road near Pimperena in southern Mali. UC Davis researchers have announced that mosquito preference for human-versus-animal biting has a genetic component. (Photo by Yoosook Lee, UC Davis)
Safety of GMOs debated online
Alison Van Eenennaam, UC ANR Cooperative Extension specialist in the Department of Animal Sciences at UC Davis, said research has shown that genetically engineered crops do not pose a risk to human health.
"There's a recent review paper where they summarized data from 1,700 different studies, and about half of those are publicly funded. And basically the results of those studies have been that there haven't been any unique risks or hazards associated with the use of this breeding method in the production of crops," she said.
The counter point was offered by Thierry Vrain, a soil biologist and genetic engineer with Agriculture Canada. He focused on the fact that more than 90 percent of the genetically engineered crops now in use were altered to be resistant to the herbicide glyphosate. He said this fact results in overuse of the herbicide.
"In terms of specific toxicity of the molecule glyphosate, which has very little acute toxicity - as it is advertised, it is safer than table salt. But in terms of chronic toxicity over time, over weeks and months, it will damage the microbiome and induce all kinds, all kinds of symptoms. In mice, and probably in humans," Vrain said.
Van Eenannaam tried to keep the discussion focused on the safety of GMOs.
"I think the most misunderstood thing is it's a breeding method that can be used to introduce all sorts of crop traits into crops and animals, and we always seem to get discussing the one particular application rather than looking at how it could be used to address many different problems that are associated with agriculture, including things like drought tolerance, disease resistance, biofortification of crops," she said.
Vrain agreed with most of Van Eenennaam's points.
"I agree with you, Alison, that GMOs are not necessarily toxic, et cetera, et cetera," he said. "There's all kinds of benefits, it's a very powerful technology. Used properly, it's probably very beneficial to humanity.
At the end of the debate Vrain reiterated his concern that the preponderance of GMOs are for glyphosate-resistant crops.
UC researchers discovered a gene that may yield hot-weather lettuce
The study also included researchers from Arcadia Biosciences and Acharya N.G. Ranga Agricultural University, India.
The finding is particularly important to the nearly $2 billion lettuce industries of California and Arizona, which together produce more than 90 percent of the nation's lettuce.
"Discovery of the genes will enable plant breeders to develop lettuce varieties that can better germinate and grow to maturity under high temperatures," said the study's lead author Kent Bradford, a professor of plant sciences and director of the UC Davis Seed Biotechnology Center.
"And because this mechanism that inhibits hot-weather germination in lettuce seeds appears to be quite common in many plant species, we suspect that other crops also could be modified to improve their germination," he said. "This could be increasingly important as global temperatures are predicted to rise."
With California temperatures predicted to rise by 2.7F by 2050, this study could prove to be extremely vital to California agriculture.
Read more on the UC ANR news blog.
Gene discovery may yield lettuce that will sprout in hot weather
The study also included researchers from Arcadia Biosciences and Acharya N.G. Ranga Agricultural University, India.
The finding is particularly important to the nearly $2 billion lettuce industries of California and Arizona, which together produce more than 90 percent of the nation's lettuce. The study results appear online in the journal The Plant Cell.
"Discovery of the genes will enable plant breeders to develop lettuce varieties that can better germinate and grow to maturity under high temperatures," said the study's lead author Kent Bradford, a professor of plant sciences and director of the UC Davis Seed Biotechnology Center.
"And because this mechanism that inhibits hot-weather germination in lettuce seeds appears to be quite common in many plant species, we suspect that other crops also could be modified to improve their germination," he said. "This could be increasingly important as global temperatures are predicted to rise."
Most lettuce varieties flower in spring or early summer and then drop their seeds -- a trait that is likely linked to their origin in the Mediterranean region, which, like California, characteristically has dry summers. Scientists have observed for years that a built-in dormancy mechanism seems to prevent lettuce seeds from germinating under conditions that would be too hot and dry to sustain growth.
While this naturally occurring inhibition works well in the wild, it is an obstacle to commercial lettuce production.
In the California and Arizona lettuce industries, lettuce seeds are planted somewhere every day of the year -- even in September in the Imperial Valley of California and near Yuma, Ariz., where fall temperatures frequently reach 110 degrees.
In order to jump-start seed germination for a winter crop in these hot climates, lettuce growers have turned to cooling the soil with sprinkler irrigation or priming the seeds to germinate by pre-soaking them at cool temperatures and re-drying them before planting -- methods that are expensive and not always successful.
In the new study, researchers turned to lettuce genetics to better understand the temperature-related mechanisms governing seed germination. They identified a region of chromosome six in a wild ancestor of commercial lettuce varieties that enables seeds to germinate in warm temperatures. When that chromosome region was crossed into cultivated lettuce varieties, those varieties gained the ability to germinate in warm temperatures.
Further genetic mapping studies zeroed in on a specific gene that governs production of a plant hormone called abscisic acid -- known to inhibit seed germination. The newly identified gene "turns on" in most lettuce seeds when the seed is exposed to moisture at warm temperatures, increasing production of abscisic acid. In the wild ancestor that the researchers were studying, however, this gene does not turn on at high temperatures. As a result, abscisic acid is not produced and the seeds can still germinate.
The researchers then demonstrated that they could either "silence" or mutate the germination-inhibiting gene in cultivated lettuce varieties, thus enabling those varieties to germinate and grow even in high temperatures.
Other researchers on the study were: Post-doctoral researcher Heqiang Huo and staff researcher Peetambar Dahal, both of the UC Davis Department of Plant Sciences; Keshavulu Kunusoth of Acharya N.G.
Ranga Agricultural University, India; and Claire McCallum of Arcadia Biosciences, which provided the lettuce lines with variants of the target gene to help confirm the study's findings.
Funding for the study was provided the U.S. Department of Agriculture National Institute of Food and Agriculture and the National Science Foundation.
