Potato blight, caused by a water mould called Phytophthora infestans, can rapidly obliterate potato crops, and is one of the biggest problems in potato farming.
Working together, scientists from Wageningen University & Research and Teagasc, the Irish Agriculture and Food Development Authority, have developed a two-pronged approach: a genetically modified potato, along with a new pest management strategy, that combine for healthy crops with minimal fungicide use. | READ MORE
Potato is the third most important crop in human nutrition, after wheat and rice. Knowing and improving its agronomic, nutritional and industrial aspects is essential and in this task a group of researchers specialized in biotechnology of the INTA Balcarce is focused.
Recently, with a trajectory more than 7 years in gene editing technologies, they were able to confirm that the DNA sequence had been modified, while they hope to corroborate the shutdown of the gene that causes enzymatic browning in potatoes ( Solanum tuberosum L. ).
When applying this technique, the team led by Feingold focused on a polyphenol oxidase gene, whose enzyme causes browning in tubers when they are cut and exposed to air. | For the full story, CLICK HERE.
The international team increased the levels of a photosynthetic protein (PsbS) to conserve water by tricking plants into partially closing their stomata, the microscopic pores in the leaf that allow water to escape. Stomata are the gatekeepers to plants: When open, carbon dioxide enters the plant to fuel photosynthesis, but water is allowed to escape through the process of transpiration. | READ MORE
Hoping to find an alternative to chemical sprout suppressors, the EU-funded GENSPI (Genomic Selection for Potato Improvement) project has developed a genetic marker system to identify plants that display a resistance to glucose and fructose formation. Their tubers can be stored at three or four degrees, low enough to keep sprout growth at bay for very long periods.
“Glucose and fructose formed during cold storage can cause very dark fry colours, leaving potato crisps and chips with an unacceptably bitter taste. The sugars can also cause a build-up of acrylamide, a potential carcinogen,” says Dan Milbourne, GENSPI project coordinator.
GENSPI developed new genomic selection breeding methodologies that will allow potato breeders to select the varieties of potato that seem to be resistant to sweetening at low temperatures.
To do this, researchers gathered a large collection of potato plants and fried thousands of tubers – the equivalent to 10,000 bags of potato crisps – that had been held in different storage conditions. They then measured their colour once fried and drew the links between fry colour and the genetic variation of the plant.
“Because the fry colour is controlled by many genes the best approach was to scan the genome for variation at many sites to find correlations between colour and genetic variation,” explains Milbourne.
Researchers then used the latest techniques in genome sequences – known as next generation sequencing – to identify over 100,000 regions across the genome where the DNA sequence varied among the plants. They combined data on variation on the potato phenotype and genome to build statistical models that could predict fry colour from DNA sequencing information.
“From the 100,000 regions showing genetic variation between the breeding lines, we were able to identify a smaller number of DNA markers that gave us a good ability to predict fry colour,” says Stephen Byrne, the Marie Skłodowska-Curie fellow who carried out the research. “This means we can develop an inexpensive DNA-based test to predict fry colour that can be applied to tens of thousands of plants in a potato breeding program.”
Traditionally, potato breeders inter-cross plant varieties to produce up to 100,000 seedlings, and then eliminate poorly performing plant types over a period of 10 years. Varieties that are resistant to glucose and fructose formation can only be identified at the end of this time, meaning that many potential varieties have already been eliminated from the breeding process.
GENSPI carried out its research in collaboration with a commercial potato breeding program led by Denis Griffin. Its newly-developed technique allows resistant plants to be identified early in the 10-year breeding program. The team hopes the project will lead to the release of one or more varieties that give an excellent fry colour even at low-temperature storage, avoiding chemical sprout suppressants.
“We hope to see these varieties released in the next five years,” concludes Griffin.
Each year, Agriculture and Agri-Food Canada's Research and Development Centre in Fredericton hosts a fair of sorts, where researchers get to show off new varieties to farmers and companies. READ MORE
The CFIA and HC announced recently that the Arctic Fuji variety “did not pose a greater risk to human health than apples currently available on the Canadian market. In addition, Health Canada also concluded that the Arctic Fuji apple would have no impact on allergies, and that there are no differences in the nutritional value of the Arctic Fuji apple compared to other traditional apple varieties available for consumption."
Arctic Fuji trees will join the growing commercial orchards of Arctic Golden and Arctic Granny apples in spring 2018.
“Canadian approval of the non-browning Arctic Fuji is great news for our company and even more exciting for families looking to add another favorite apple variety to their healthy diets and lifestyles,” said Neal Carter, president of OSF. “There has been very strong interest from retailers as we launched our first product – fresh, preservative-free Arctic Golden slices – and we look forward to introducing additional Arctic non-browning varieties into Canada and U.S. markets soon.”
Arctic apples have a unique trait that prevents enzymatic browning even when apples are bitten, sliced, or bruised. Through biotechnology, the enzyme in apples responsible for browning has been turned off. The resulting non-browning advantage benefits every sector of the supply chain, reducing food waste and boosting product appeal.
“It’s an exciting time at OSF,” said Carter. “This latest announcement allows us to continue looking ahead toward providing new non-browning varieties and additional value-added fruits and vegetables. Arctic apples are just the beginning for OSF.”
The announcement follows approval by the U.S. Department of Agriculture Animal and Plant Health Inspection Service (USDA APHIS) of the Arctic Fuji variety, granted September 23, 2016. Arctic apples will be available commercially in select U.S. cities this fall and in additional areas of North America over the coming years as fruit availability increases.
The new potatoes – called AAC Confederation and AAC Canada Gold-Dorée – were recently named by Progest 2001 Inc. based out of Sainte-Croix, Quebec, and Canadian Eastern Seed Growers Inc. based out of New Brunswick, respectively. The “AAC” in both names is a nod to their AAFC origins!
Both company presidents are really excited about the commercial potential these potatoes possess and feel they could rival Yukon Gold. AAFC potato breeder Dr. Benoit Bizimungu couldn’t agree more and describes both potatoes as having good yield and disease resistance profiles that makes them more profitable to produce and can be considered an improvement on Yukon Gold.
“Taste and texture are important,” said André Gagnon, president of Progest 2001 Inc. “We need tasty special potatoes that fit customer needs. We feel that AAC Confederation has the potential to become a popular yellow variety for consumers.”
When naming AAC Canada Gold Dorée, André Côté – co-owner of the Eastern Seed Growers Inc. with his brother, Eric Côté – said they were inspired by this potato’s golden colour when choosing its name.
“We chose AAC Canada Gold-Dorée for its golden flesh and its golden potential as a winner in the markets.”
Both AAC Confederation and AAC Canada Gold-Dorée are graduates of the AAFC potato breeding program, based in Fredericton, NB.
“A lot of work goes into developing a new potato variety,” said Dr. Benoit Bizimungu, a research scientist with AAFC. “For instance, the AAC Canada Gold-Dorée was six years in development before being released in 2015 to the potato industry to be evaluated of commercial potential. It is no surprise that the potato was taken up so quickly by the industry because it has great attributes.”
Dr. Bizimungu believes this latest licensing demonstrates the breeding program is making progress in identifying the kind of potatoes the industry needs and shows the value of the department’s national breeding program.
Each year under the Accelerated Release Program, AAFC releases 10 to 15 potato selections during a special Potato Release Open House for industry to consider.
These potatoes provide options to best meet the needs of Canadian consumers and producers. If industry likes what they see, they can conduct field trials of the selections and eventually bid for sole evaluation rights.
As for AAC Confederation and AAC Canada Gold-Dorée, the two companies expect to begin selling seed for the two new varieties by 2020.
Potatoes are the fourth most consumed food crop in the world and its genome is complex. It’s an auto-tetraploid, which means that each potato cell contains four nearly identical copies of each chromosome and gene, making the assembly and phasing of the four copies extremely difficult for traditional technologies.
NRGene has completed the phased assembly of three commercial potato varieties.
It’s hoped the potato pangenome will synergize the assembly information to contribute a comprehensive genomics view of the potato genome. The group, led by potato researcher Dr. Richard Finkers and Dr. Richard Visser from WUR, is seeking other researchers from academia and industry to join the project to enrich the pan-genome analysis and thus better characterize the natural genetic diversity of the species.
“Potato research and breeding faced significant difficulties during the last 100 years,” says Dr. Finkers of WUR. “NRGene’s genomes and pan-genome analysis will allow us to map traits on the level of haplotypes, which was previously almost impossible.”
Dr. Finkers will present the potato genome research at the PAG XXVI conference, Jan. 16, 2018, in San Diego, Calif.
Namely, what to do with her research on advanced wine grape selections for cold climate wine growing regions.
“Breeding work for wine grapes is a very slow process,” says Fisher. “Not only are you trying to find a plant that fits a climate, but it also needs to fit into a wine profile wineries are looking for.”
Vines can take up to four years to become established in the soil and produce quality grapes. To determine if the fruit fits a desired wine profile, it must be processed into wine, and then assessed after aging for three or more years.
“We’re looking for good quality reds that are tough in terms of agronomic potential and can withstand cold winters and wet growing seasons, that aren’t susceptible to disease or weather,” says Fisher.
Fisher says her work holds potential for larger Canadian wineries that want a sturdy but neutral wine that can be used for blending with other grapes. But to get meaningful results, the hybrids need more time. After retiring and losing access to land and laboratories, Fisher found new ways to continue her research.
“I was left with the dilemma of what to do with the plant material when it was at a stage that wasn’t even close to being presented to the public,” Fisher says. “Fortunately, Wes Wiens of VineTech Canada, a local nursery, donated land so the research could continue. It was tough land on a cold site – perfect, for my purposes.”
Fisher worked with the VineTech team to repropagate 40 plant selections from the VRIC property, based on genealogy and a superficial look at the most recent crop. She applied for funding through the Gryphon’s LAAIR Program and hired a summer student to collect data from the field. She also enlisted nearby Niagara College to make wine with the harvested grapes.
“Baco has had a good run in Niagara, but this is a chance to develop a new hybrid that offers a good amount of disease resistance and cold tolerance, perhaps with less acidity,” says Fisher.
Next, Fisher says project partners will test the wine quality, which she hopes to bring to two large wineries, to attract further interest and a long-term home for the research.
Broccoli has been grown in Europe for centuries, but it has only been grown in North America since the late 1800s, when it was probably introduced by Italian immigrants. Although California is the major producing state, broccoli is grown in nearly every other state, especially along the eastern seaboard.
The likelihood of high-temperature stress occurring in a given location or season is the main factor limiting where and when the crop can be grown. Breeding heat-tolerant broccoli cultivars could extend the growing season, expand production areas, and increase resilience to fluctuating temperatures, but efforts to do this have been limited by a lack of knowledge about the genetics of heat tolerance.
Agricultural Research Service (ARS) plant geneticist Mark Farnham and his team at the U.S. Vegetable Laboratory in Charleston, South Carolina, are filling in those knowledge gaps. They have developed and characterized genetic sources of heat tolerance in broccoli. These results were published in Theoretical and Applied Genetics in March 2017.
The team evaluated a group of broccoli plants that Farnham developed for the ability to tolerate high-temperature stress during summer.
“We identified genetic markers associated with resistance to heat damage in these plants,” says Farnham. “An important finding of this work is that the resistance trait is a complex trait controlled by many genes, which makes it a bit harder to work with. However, these markers are of great interest to public and private broccoli breeders, who can use some additional tools in their work to accelerate the development of heat-tolerant broccoli cultivars.”
To determine how well Farnham’s heat-tolerant broccoli will do in different stress environments, he is working with scientists at land-grant universities on the eastern seaboard that are growing his broccoli in warm-temperature field trials. Once they verify that his broccoli will do well under adverse conditions in different locations, it will be made available for research purposes or for use by commercial seed companies and breeders.
The heat-tolerant broccoli could help expand future growing possibilities significantly, helping to meet the demand for the nutritious vegetable.
A serving of the yellow-orange lab-engineered potato has the potential to provide as much as 42 per cent of a child’s recommended daily intake of vitamin A and 34 per cent of a child’s recommended intake of vitamin E, according to a recent study co-led by researchers at Ohio State University.
Women of reproductive age could get 15 per cent of their recommended vitamin A and 17 per cent of recommended vitamin E from that same 5.3 ounce (150 gram) serving, the researchers concluded.
The study appears in the journal PLOS ONE.
Potato is the fourth most widely consumed plant food by humans after rice, wheat and corn, according to the U.S. Department of Agriculture. It is a staple food in some Asian, African and South American countries where there is a high incidence of vitamin A and vitamin E deficiencies.
“More than 800,000 people depend on the potato as their main source of energy and many of these individuals are not consuming adequate amounts of these vital nutrients,” said study author Mark Failla, professor emeritus of human nutrition at Ohio State.
“These golden tubers have far more vitamin A and vitamin E than white potatoes, and that could make a significant difference in certain populations where deficiencies – and related diseases – are common,” said Failla, a member of Ohio State’s Foods for Health Discovery Theme.
Vitamin A is essential for vision, immunity, organ development, growth and reproductive health. And Vitamin A deficiency is the leading cause of preventable blindness in children. Vitamin E protects against oxidative stress and inflammation, conditions associated with damage to nerves, muscles, vision and the immune system.
In Failla’s lab, researchers created a simulated digestive system including a virtual mouth, stomach and small intestine to determine how much provitamin A and vitamin E could potentially be absorbed by someone who eats a golden potato. Provitamin A carotenoids are converted by enzymes into vitamin A that the body can use. Carotenoids are fat-soluble pigments that provide yellow, red and orange colours to fruits and vegetables. They are essential nutrients for animals and humans.
“We ground up boiled golden potato and mimicked the conditions of these digestive organs to determine how much of these fat-soluble nutrients became biologically available,” he said.
The main goal of the work was to examine provitamin A availability. The findings of the high content and availability of vitamin E in the golden potato were an unanticipated and pleasant surprise, Failla said.
The golden potato, which is not commercially available, was metabolically engineered in Italy by a team that collaborated with Failla on the study. The additional carotenoids in the tuber make it a more nutritionally dense food with the potential of improving the health of those who rely heavily upon potatoes for nourishment.
While plant scientists have had some success cross-breeding other plants for nutritional gain, the improved nutritional quality of the golden potato is only possible using metabolic engineering – the manipulation of plant genes in the lab, Failla said.
While some object to this kind of work, the research team stresses that this potato could eventually help prevent childhood blindness and illnesses and even death of infants, children and mothers in developing nations.
“We have to keep an open mind, remembering that nutritional requirements differ in different countries and that our final goal is to provide safe, nutritious food to nine billion people worldwide,” said study co-author Giovanni Giuliano of the Italian National Agency for New Technologies, Energy and Sustainable Development at the Casaccia Research Centre in Rome.
Failla said “hidden hunger” – deficiencies in micronutrients – has been a problem for decades in many developing countries because staple food crops were bred for high yield and pest resistance rather than nutritional quality.
“This golden potato would be a way to provide a much more nutritious food that people are eating many times a week, or even several times a day,” he said.
The work sheds light on longstanding questions about the origin and early evolution of sex chromosomes, and at the same time serves as a foundation for asparagus breeding efforts.
Their research, the first confirmation of early models on how sex chromosomes diverge within the same species, was published recently in Nature Communications.
While most flowering plants are hermaphrodites, garden asparagus plants are typically either male (XY) or female (XX), although YY “supermales” can be produced in the greenhouse. Growers prefer all-male plants, as they live longer and do not self-seed. Breeders produce all-male XY seed by crossing an XX female, with a YY supermale. Until now the differences between asparagus X and Y chromosomes were not understood and breeders were not able to distinguish XY males from YY supermales without time-consuming test crosses.
“One of the things that we were able to do pretty early in our collaboration was to identify genetic markers that allowed breeders to efficiently distinguish XY males from YY males and then use those YY males to produce all-male seed,” said Jim Leebens-Mack, professor of plant biology and senior author on the study.
Understanding the genetic variation in plants that allows for XY and YY males was advanced by identification of the genes that determine sex, which paves the way for more efficient development and production of valuable hybrid asparagus plants.
“In addition to more rapid identification of sex genotypes, our collaborators are now able to manipulate the asparagus Y chromosome to convert males to females or hermaphrodites. In the near future, breeders will be able to cross whatever lines they want, without having to look within a particular line for the female that has one set of characteristics, and in another line for a male with complementary traits,” Leebens-Mack said.
Questions about the great diversity of sexual systems in plants go back to Charles Darwin, and a two-gene model for the origin of sex chromosomes was coined by Danish geneticist Mogens Westergaard in the early 20th century. But the theory was impossible to test through analyses of humans and mammal sex chromosomes, where divergence of the X and Y chromosomes happened tens of millions ago.
Flowering plants like asparagus, however, have more recent origins of separate sexes and sex chromosomes, presenting an ideal opportunity to test Westergaard's two-gene model while at the same time aiding crop breeding programs.
The researchers found that, as predicted by Westergaard and others, linkage of a gene necessary for male function with a gene stunting development of female organs on a small portion of the Y chromosome was the starting point for the evolution of asparagus sex chromosomes.
“Over the last hundred years, evolutionary biologists have hypothesized several ways that a regular pair of chromosomes can evolve into an X and Y pair that determine sex,” said Alex Harkess, former doctoral student in the Leebens-Mack lab and lead author on the study. “Our work confirms one of these hypotheses, showing that a sex chromosome pair can evolve by mutations in just two genes – one that influences pollen (male) development, and one that influences pistil (female) development.”
“Breeders have dreamed about manipulating sex determination in garden asparagus for decades,” said co-author Ron van der Hulst of Limgroup breeding company in the Netherlands. “Identification of sex determination genes in asparagus will now allow us to produce plants with male, female and bisexual flowers, and greatly speed the development of inbred lines to produce elite hybrid seed.”
Co-author and Italian asparagus breeder Agostino Falavigna also noted that the reference genome for garden asparagus will enable him and other breeders to more efficiently use wild relatives as sources for genes that could enhance disease resistance, spear quality, flavour, aroma and antioxidant content.
Examining the ancestors of the modern, North American cultivated potato has revealed a set of common genes and important genetic pathways that have helped spuds adapt over thousands of years. The study appears in the current issue of Proceedings of the National Academy of Sciences.
Robin Buell, Michigan State University Foundation professor of plant biology and senior author of the paper, shows potential genetic keys that could ensure the crop will thrive in the future.
“Worldwide, potato is the third most important crop grown for direct human consumption, yet breeders have struggled to produce new varieties that outperform those released over a century ago,” Buell said. “By analyzing cultivated potato and its wild relatives using modern genomics approaches, we were able to reveal key factors that could address food security in 21st century agriculture.”
Cultivated potatoes – domesticated from wild Solanum species, a genetically simpler diploid (containing two complete sets of chromosomes) species – can be traced to the Andes Mountains in Peru, South America.
While the exact means of the potato migration are unknown, spuds essentially spread worldwide since their domestication some 8,000 to 10,000 years ago. As potatoes were taken from the more equatorial regions of Peru and Bolivia to the southern parts of South America, they became adapted to longer summer days in Chile and Argentina.
One aspect that is known is how Spanish conquistadors introduced potatoes upon return from their South American exploits to the European continent, where potatoes were quickly adapted as a staple crop. As the explorers ventured from Europe to North America, they also brought potatoes to the new world.
Scientific explorer Michael Hardigan, formerly at MSU and now at the University of California-Davis, led the team of MSU and Virginia Polytechnic Institute and State University scientists. Together, they studied wild landrace (South American potatoes that are grown by local farmers) and modern cultivars developed by plant breeders. The result was the largest crop re-sequencing study to date.
Not only did it involve substantial re-sequencing of potato, but it also tackled one of the most-diverse crop genomes. The modern spuds found in today’s kitchens are genetically complex tetraploid potatoes, having four-times the regular number of chromosomes. Potatoes’ complex genome harbors an estimated 39,000 genes. (In comparison, the human genome comprises roughly 20,000 genes.)
From the large gene pool, the researchers identified 2,622 genes that drove the crop’s early improvement when first domesticated.
Studying the gene diversity spectrum, from its wild past to its cultivated present, can provide an essential source of untapped adaptive potential, Buell said.
“We’ll be able to identify and study historic introgressions and hybridization events as well as find genes targeted during domestication that control variance for agricultural traits,” she said. “Many of these help focus on adapting to different climates, fending off different pathogens or improving yield, keys that we hope to better understand to improve future breeding efforts.”
For example, wild potatoes reproduce through berries and seeds. Cultivated potatoes are asexual and are food and seed in one. (Anyone who’s left a potato in a dark pantry too long has witnessed this trait firsthand.)
The researchers present evidence of the signatures of selection in genes controlling this change. They also shed light on a role of wild species in genetic pathways for fighting pests and processing sugars for food. Diving into somewhat obscure territory, they looked at potential genetic sources that control circadian rhythm; yes, plants also have 24-hour clocks controlling biological processes.
“We knew about their physiological traits, but we didn’t know what genes were involved,” Buell said. “As potatoes were moved, they had to adapt to longer days, more hours of sunlight. We’re now starting to understand what’s happening at the genetic level and how wild Solanum species evolved to long-day adapted tetraploid potatoes.”
Enter Thomas Lubbserstedt, a professor of agronomy at Iowa State University. Lubberstedt and a team of ISU researchers recently received a four-year, $1 million grant from the U.S. Department of Agriculture to advance organic corn varieties. By the end of the project, the team aims to have identified elite varieties that will improve the performance of corn under organic growing conditions.
“Our main goal is to figure out whether new genetic mechanisms can benefit organic field and sweet corn varieties,” Lubberstedt said. “We want to develop traits that can do well under organic conditions.”
Lubberstedt said the research could lead to organic corn with better resistance to disease, weeds pests and environmental stress.
Farmers who label their products as organic adhere to standards meant to restrict the use of synthetic inputs that include many fertilizers and pesticides in an effort to maintain environmental sustainability. Demand for organic products is growing as consumers become more concerned about how their food is produced and how it affects the environment, said Kathleen Delate, a professor of agronomy and member of the research team. Delate said the U.S. market for organic products reached $47 billion in 2016.
The ISU research team intends to address limitations imposed by organic practices by finding genetic mechanisms that lead to better-performing corn varieties that can still meet organic standards. Lubberstedt will focus on varieties that carry a genetic mechanism for spontaneous haploid genome doubling. This allows a corn plant to carry only the genes of its mother.
Researchers can use these haploids to create totally inbred genetic lines in two generations, whereas traditional plant breeding takes five or six generations to produce inbred lines, Lubberstedt said. These inbred lines are more reliable for evaluation in an experimental setting because they carry no genetic variation that could influence results. That makes it easier to identify lines with superior traits, he said.
It was a lofty goal, considering none of the cider apple varieties were readily available to Ontario growers. But with hard cider leading the growth category at LCBO stores, the group saw an opportunity to grow the seven per cent market share Ontario cider currently has of this segment. And in the process, the effort would support locally-grown cider to strengthen this made-in-Ontario industry.
“Ontario growers have been producing local cider for years using fresh apple varieties and they make a good cider,” says Tom Wilson, owner/operator of Spirit Tree Estate Cidery in Caledon and OCCA chair. “But we know that European varieties grown specifically for the cider market contain a much better flavour profile and tannin content to make high-quality hard cider.”
One of OCCA’s first projects involved grassroots research to evaluate European cider apple cultivars under Ontario’s growing conditions to understand the agronomics of growing the varieties and evaluating the attributes of the resulting juice for cider quality.
“Our group is part of a three-phase project to build a bigger cider industry in Ontario,” says Wilson, who is a third-generation Ontario apple grower. “There is very limited information available for our members on how European cider varieties will perform in Ontario. We really need science-based information to help growers make informed choices about using cider apple cultivars that will create the type of cider the market is craving.”
The first phase of the project was to source the genetic material to grow some of the European cider apple cultivars. The second phase, supported in part by Growing Forward 2 (GF2) funding accessed through the Agricultural Adaptation Council (AAC) is where the grassroots, field research took place.
Five orchards around the province were chosen to plant 29 new cider apple cultivars to gather local performance data on how the trees grow and the attributes of the resulting juice.
While OCCA is learning the finer points of growing European cider cultivars, they also commissioned an economic impact study of the Ontario industry.
Building a stronger cider industry in Ontario will return greater economic activity for the 25 craft cider producers, and in the process deliver many spin-off contributions to the broader community.
“The latest economic impact study we commissioned in late 2016 identified a number of other benefits for our growing sector, including tourism, rural development, attracting new businesses, community events and contributing to employment and training opportunities in the areas where our members operate,” says Wilson.
OCCA’s commissioned report provides encouraging statistics about the contributions of the Ontario industry to the economy, and the results confirm a growing opportunity for Ontario growers and cider lovers. Ontario-grown cider contains all the elements of a great agri-food success. Consumers are ready and eager to support local, Ontario’s cider growers are making great strides with new cider apple varieties and hard cider is a beverage category that continues to exceed growth targets year after year.
The solid dark green “Emerald” type watermelon may be new to some in the industry, but varieties in the product line have been successful over the last few years, explains Kike Rossell, a regional watermelon product specialist with Bayer.
“The Emerald type varieties have been grown commercially throughout the North and Central America watermelon production regions over the last three to four years. They have proven to be consistent varieties from an agronomic standpoint while also providing high brix, excellent flavour, and a firm, crisp texture.”
Growers and shippers agree the “Emerald” work extremely well as the dark green rind makes it stand out from other watermelon varieties.
“I’ve had customers request them,” said Greg Leger of Leger & Sons, a Georgia-based watermelon grower/shipper that has grown and sold the Emerald type for the last few seasons.
The Emerald type line offers varieties for the fresh and processing markets with 60, 45, and 36 count offerings and a dark red firm-flesh that is desirable for processors.
“After the success we’ve seen the last few years, we knew it was time to promote the Emerald type in a big way to the industry,” says Rossell. “We are excited about the potential of the varieties for our customers.”
But if you put a ruby raspberry up against a crimson beet and look closely, you might just notice: they are different reds.
Millions of years ago, one family of plants – the beets and their near and distant cousins – hit upon a brand new red pigment and discarded the red used by the rest of the plant world. How this new red evolved, and why a plant that makes both kinds of red pigment has never been found, are questions that have long attracted researchers puzzling over plant evolution.
Writing recently in the journal New Phytologist, University of Wisconsin-Madison Professor of Botany Hiroshi Maeda and his colleagues describe an ancient loosening up of a key biochemical pathway that set the stage for the ancestors of beets to develop their characteristic red pigment. By evolving an efficient way to make the amino acid tyrosine, the raw material for the new red, this plant family freed up extra tyrosine for more uses. Later innovations turned the newly abundant tyrosine scarlet.
The new findings can aid beet breeding programs and provide tools and information for scientists studying how to turn tyrosine into its many useful derivatives, which include morphine and vitamin E.
“The core question we have been interested in is how metabolic pathways have evolved in different plants, and why plants can make so many different compounds,” says Maeda. “Beets were the perfect start for addressing the question.”
The vast majority of plants rely on a class of pigments called anthocyanins to turn their leaves and fruits purple and red. But the ancestors of beets developed the red and yellow betalains, and then turned off the redundant anthocyanins. Besides beets, the colour is found in Swiss chard, rhubarb, quinoa and cactuses, among thousands of species. Betalains are common food dyes and are bred for by beet breeders.
When Maeda lab graduate student and lead author of the new paper Samuel Lopez-Nieves isolated the enzymes in beets that produce tyrosine, he found two versions. One was inhibited by tyrosine – a natural way to regulate the amount of the amino acid, by shutting off production when there is a lot of it. But the second enzyme was much less sensitive to regulation by tyrosine, meaning it could keep making the amino acid without being slowed down. The upshot was that beets produced much more tyrosine than other plants, enough to play around with and turn into betalains.
Figuring that humans had bred this highly active tyrosine pathway while selecting for bright-red beets, Lopez-Nieves isolated the enzymes from wild beets.
“Even the wild ancestor of beets, sea beet, had this deregulated enzyme already. That was unexpected. So, our initial hypothesis was wrong,” says Lopez-Nieves.
So he turned to spinach, a more distant cousin that diverged from beets longer ago. Spinach also had two copies, one that was not inhibited by tyrosine, meaning the new tyrosine pathway must be older than the spinach-beet ancestor. The researchers needed to go back much further in evolutionary time to find when the ancestor of beets evolved a second, less inhibited enzyme.
Working with collaborators at the University of Michigan and the University of Cambridge, Maeda’s team analyzed the genomes of dozens of plant families, some that made betalains and others that diverged before the new pigments had evolved. They discovered that the tyrosine pathway innovation – with one enzyme free to make more of the amino acid – evolved long before betalains. Only later did other enzymes evolve that could turn the abundant tyrosine into the red betalains.
“Our initial hypothesis was the betalain pigment pathway evolved and then, during the breeding process, people tweaked the tyrosine pathway in order to further increase the pigment. But that was not the case,” says Maeda. “It actually happened way back before. And it provided an evolutionary stepping stone toward the evolution of this novel pigment pathway.”
The takeaway of this study, says Maeda, is that altering the production of raw materials like tyrosine opens up new avenues for producing the varied and useful compounds that make plants nature’s premier chemists.
For some unknown ancestor of beets and cactuses, this flexibility in raw materials allowed it to discover a new kind of red that the world had not seen before, one that is still splashed across the plant world today.
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Field Day: Sprouts, Seedlings & Indoor GrowingWed Jul 11, 2018
Maritime Wild Blueberry Field DayThu Jul 12, 2018
2018 NAFDMA Advanced Learning RetreatSat Jul 28, 2018 @ 8:00AM - 05:00PM
Carrot FestFri Aug 17, 2018