How do plant roots grow in unpredictable temperatures?
Salk Institute scientists uncover an internal “thermostat” that lets plants sense temperature and adapt growth, opening potential new paths to more resilient crops
image:
Lucia Strader led a study discovering an internal “thermostat” that lets plants sense temperature and adapt their growth accordingly.
view moreCredit: Salk Institute
LA JOLLA (April 9, 2026)—Plants can’t move to escape the heat like humans can—they are forced to adapt. As temperatures fluctuate, one key survival strategy is the ability of roots to keep growing, allowing plants to access water and nutrients further away in the soil. But how do plants sense temperature and translate it into growth?
Salk Institute scientists have uncovered a new answer in a familiar plant hormone: auxin. Auxin is at the center of plant growth, governing everything from cell elongation to root and stem development. But it’s not the center of this story—instead, the latest research found auxin’s partner proteins serve as internal plant “thermostats.” These partner proteins directly sense temperature, then change genetic programs to direct root growth accordingly.
The findings, published in Nature Communications on March 27, 2026, could be used in future efforts to engineer plants that withstand more extreme temperatures.
“It’s been known for a long time that plants grow at different rates at different temperatures,” says Lucia Strader, PhD, senior author of the study and a professor and holder of the Howard H. and Maryam R. Newman Chair in Plant Biology at Salk. “Now we have discovered this protein that can directly sense temperature and consequently adjust root growth, which is a huge step toward understanding how plants integrate environmental cues into life.”
A growth signal with a “Goldilocks” problem
Auxin is a master regulator of plant growth—and it’s also a bit like Goldilocks. Strader explains that “it has to be just right, because too little or too much can inhibit growth.”
For decades, scientists thought that temperature influenced plant growth mainly by altering hormone levels, such as auxin. Scientists have long known that warm temperatures increase both auxin levels and root growth—but that creates a paradox, since high auxin typically slows root cell elongation.
So, what else could be controlling root growth in response to temperature?
An internal thermostat and protein reservoir in plant cells
Auxin acts through Auxin Response Factor transcription factors (ARFs), proteins that regulate the expression of growth genes. The team discovered that these ARFs directly sense temperature. At cooler temperatures, ARFs are stored in inactive clusters inside the cell, like a reserve. As temperatures rise, the proteins become more soluble, dissociate from these clusters, and move into the nucleus, where they activate growth-related genes.
“You have this reservoir of protein that can be activated depending on the environment, and temperature allows the cell to shift more of that protein into an active form,” says first author Edward Wilkinson, PhD, a former graduate student researcher in Strader’s lab at Duke University. "We think this is something to do with the properties of the protein itself—at higher temperatures, it is more stable and more soluble, so it can readily accumulate and drive temperature responses."
This system allows plants to respond quickly to environmental changes by redistributing existing proteins rather than making new ones. “You can think of it as a built-in thermostat within the cell—a very clever way to regulate growth,” adds co-first author Katelyn Sageman-Furnas, PhD, a postdoctoral researcher in Strader’s lab at Duke University.
This dynamic system gives plants a powerful advantage. Instead of making new proteins from scratch, they can rapidly adjust growth by redistributing proteins they already have.
Why does temperature sensing matter in crops?
Understanding how plants sense and respond to environmental stressors is increasingly important for agriculture.
Scientists’ newfound ability to identify molecular components that act as temperature sensors and protein activators opens the possibility of designing crops that continue to grow at higher temperatures.
Because root growth is essential for accessing water and nutrients, this kind of resilience could help protect crop productivity under challenging conditions.
An international collaboration for discovery
The Salk study was published in tandem with a complementary study from the lab of Jorge Casal, PhD, at the Institute for Agricultural Plant Physiology and Ecology (IFEVA) at the University of Buenos Aires. After meeting at a conference, Strader and Casal decided to create distinct research plans with one shared goal: to uncover how plants turn environmental signals into growth.
“This kind of discovery really represents Salk’s collaborative spirit, and how our culture encourages relationships within and beyond our campus,” says Strader. “Our cooperation helped optimize resources, getting us closer to understanding plant signaling without competing or wasting time or money.”
Both papers were published on the same day, and Strader and Casal are credited as co-authors on each other’s publications. You can read Casal’s lab’s Nature Communications paper here.
Other authors and funding
Other authors include Matías Ezequiel Pereyra and María Belén Borniego of the University of Buenos Aires.
This work was supported by the National Science Foundation, National Institutes of Health, and Duke University.
About the Salk Institute for Biological Studies
The Salk Institute is an independent, nonprofit research institute founded in 1960 by Jonas Salk, developer of the first safe and effective polio vaccine. The Institute’s mission is to drive foundational, collaborative, risk-taking research that addresses society’s most pressing challenges, including cancer, Alzheimer’s, and agricultural vulnerability. This foundational science underpins all translational efforts, generating insights that enable new medicines and innovations worldwide. Learn more at www.salk.edu
Seedlings grow longer stems under warmer conditions in a process dependent on auxin and the activity of the Auxin Response Factors (ARFs).
Credit
Salk Institute
Journal
Nature Communications
Article Title
AUXIN RESPONSE FACTOR thermostability
Genetic markers fast-track breeding of seedless muscadine grapes
New method saves time and resources in developing new grapes and muscadines
image:
Muscadines, seen growing at the Arkansas Agricultural Experiment Station's Fruit Research Station in Clarksville, are a species of native grape that resists many diseases and pests which can impact Vitis vinifera, the species that most people eat as table grapes and drink in wine. The experiment station is the research arm of the University of Arkansas Division of Agriculture.
view moreCredit: UADA photo
By John Lovett
University of Arkansas System Division of Agriculture
FAYETTEVILLE, Ark. — Using new genetic markers, fruit breeders can now tell whether grapes will be seedless and self-pollinating even years before vines bear fruit.
The approach will save time and resources in the pursuit of creating flavorful new grape varieties, including the major challenge of developing seedless muscadines on self-pollinating vines.
Margaret Worthington, associate professor of horticulture and director of the Fruit Breeding Program for the Arkansas Agricultural Experiment Station, joined colleagues at Cornell University, the U.S. Department of Agriculture, Gardens Alive! and E&J Gallo Winery in publishing a study validating a system for predicting flower sex type and seedlessness in muscadines and other grapes.
The study was conducted in association with the VitisGen3 Project and Vitis-x-Muscadinia, which are funded by the Specialty Crop Research Initiative, a USDA National Institute of Food and Agriculture federal grant program supporting research and extension efforts.
The researchers made their predictions using a genotyping platform that tests muscadine plant DNA for genetic markers — like signposts in the DNA pointing to specific traits.
The same genetic markers, which are publicly available, can also be used by wine and table grape breeders.
“This is a resource to the global breeding community,” Worthington said.
The experiment station is the research arm of the University of Arkansas Division of Agriculture, and Worthington is also part of the Dale Bumpers College of Agricultural, Food and Life Sciences at the University of Arkansas.
Broadening the scope
Scientists discovered and published the genetic mutations causing seedlessness and male sterility in grapes a few years ago. In this new study, low-cost diagnostic markers targeting those mutations were developed and validated in more than 900 Vitis-Muscadinia hybrid grapes from the Arkansas Fruit Breeding Program and about 200 cultivated and wild grapes.
Worthington and her colleagues published the study earlier this year in the Journal of the American Society for Horticultural Sciences under the title “Diagnostic KASP Markers for Flower Sex and Stenospermocarpic Seedlessness in Diverse Vitis, Muscadinia, and Wide Hybrid Populations.”
Isabella Vaughn, a graduate student in the department of horticulture, was the first author.
“She did a great job,” Worthington said of Vaughn. “She scored a lot of plants, coordinated a lot of logistics and helped us to start using the markers in our program.”
KASP, short for Kompetitive allele-specific PCR, is a proprietary but common and cost-effective genotyping platform used to detect specific genetic traits.
The researchers collected leaf samples from the plants, conducted the DNA testing, and then compared the predictions from the DNA testing with what was directly observed on the plants.
Worthington and her team correctly predicted flower sex and seedlessness with 100 percent and 99.7 percent accuracy, respectively.
“We took leaf samples from mature vines with fruit for the validation,” Worthington explained. “The DNA will stay the same regardless of plant age. So, this is proof that it will work for young seedlings, too. We started culling seedlings in 2024 in our applied program and this will be our third year using the markers.”
A century-long breeding quest
Over the past 100 years, fruit breeders have sought to create fertile crosses of muscadines — a native North American grape — with Vitis vinifera, the species behind most commercial table and wine grapes.
Muscadines are prized for their disease resistance, adaptability to the southeastern United States and distinctive flavors. Vitis vinifera offers superior fruit quality, consumer appeal, and seedlessness Worthington said.
But combining the two has proven difficult. Chromosomal differences and compatibility barriers often prevent viable, fertile hybrids, Worthington explained.
“Muscadines are in a different subgenus of grape than Vitis. They’re related, but not that closely related. It’s like a horse and a donkey,” she said.
Like horses and donkeys producing sterile mules, crosses between these grapes often result in infertile offspring.
Muscadines are not widely consumed outside of the U.S. South, but Worthington said seedlessness is key to expanding their appeal, especially for fresh markets and kids.
“What we really want is to make something that has a good size, a dry stem scar so that it can be easily picked, good post-harvest qualities and a really good texture, while keeping that muscadine flavor,” Worthington said.
Despite the challenges in developing fertile, seedless muscadines, extensive traditional breeding efforts have paid off. In 2017, Jeff Bloodworth of Gardens Alive! developed the seedless RazzMatazz® muscadine hybrid grape. That was followed in 2022 by Oh My!®, another seedless muscadine variety that is also powdery-mildew resistant.
Practice makes ‘perfect’
Beyond seedlessness, Worthington also seeks “perfect-flowered” vines for growers to allow for self-pollination and more consistent fruit production.
Wild grape species, including muscadines, are typically dioecious, meaning individual vines produce either male or female flowers. Female flowers require pollen from a nearby male plant to produce fruit. In muscadines, the discovery of two perfect-flowered selections by chance in the mid-20th century provided the foundation for all perfect-flowered cultivars of muscadines grown today.
While crosses between perfect-flowered parents might seem an ideal map to get to that seedless, perfect-flowered muscadine, Worthington said they are not always practical in breeding programs. Muscadines have very small flowers, which makes removing the male parts from perfect-flowered plants and making controlled crosses extremely difficult, Worthington said. The preferred method, to avoid having to do a costly and difficult embryo rescue, is to make crosses between seeded females and seedless perfect-flowered vines.
“The ones we want to keep, we’ll put out in the vineyard at the Fruit Research Station in Clarksville and then we’ll look at those and see how it goes,” Worthington said. “Not everything we keep is going to be good, but the markers tell us if it’s perfect-flowered and if it is seedless. It doesn’t tell us if it tastes good and has a thin skin and it’s productive.”
But, with roughly half as many plants needing to be grown out for field evaluation, Worthington will put more resources into the candidates and make more crosses.
Co-authors included Carmen Johns, research scientist and assistant fruit breeder, and Lacy Nelson, program associate, in the department of horticulture; Qi Sun at the Cornell Institute of Biotechnology at Cornell University; Cheng Zou, formerly with Cornell University; Lance Cadle-Davidson of the USDA-Agricultural Research Service’s Grape Genetics Research Unit in Geneva, New York; Claire Heinitz in the USDA-ARS National Clonal Germplasm Repository in Davis, California; Peter Cousins of E&J Gallo Winery in Modesto, California; and Jeff Bloodworth of Gardens Alive! in Hillsborough, North Carolina.
In the pipeline
Worthington said the Fruit Breeding Program has worked with seedless germplasm since 2017 and has “advanced germplasm in the pipeline” with expectations of a seedless muscadine release in the next few years.
The program released its first two muscadines in 2025: Mighty Fine™ (Cultivar: ‘AM-70′) and Altus™ (Cultivar: ‘AM-77’). Mighty Fine™ is a black, seeded, fresh-market muscadine with excellent flavor and consumer quality to be sold as a fresh fruit like table grapes. Altus™ is also black and seeded but is smaller in size and targeted for wine and juice production. Both varieties stand out for their ability to withstand colder weather compared to other muscadine varieties.
To learn more about ag and food research in Arkansas, visit aaes.uada.edu. Follow the Arkansas Agricultural Experiment Station on LinkedIn and sign up for our monthly newsletter, the Arkansas Agricultural Research Report. To learn more about the Division of Agriculture, visit uada.edu. To learn about extension programs in Arkansas, contact your local Cooperative Extension Service agent or visit uaex.uada.edu.
About the Division of Agriculture
The University of Arkansas System Division of Agriculture’s mission is to strengthen agriculture, communities, and families by connecting trusted research to the adoption of best practices. Through the Agricultural Experiment Station and the Cooperative Extension Service, the Division of Agriculture conducts research and extension work within the nation’s historic land grant education system.
The Division of Agriculture is one of 20 entities within the University of Arkansas System. It has offices in all 75 counties in Arkansas and faculty on three system campuses.
Pursuant to 7 CFR § 15.3, the University of Arkansas System Division of Agriculture offers all its Extension and Research programs and services (including employment) without regard to race, color, sex, national origin, religion, age, disability, marital or veteran status, genetic information, sexual preference, pregnancy or any other legally protected status, and is an equal opportunity institution.
# # #
Isabella Vaughn, a graduate student in the Department of Horticulture for the University of Arkansas Division of Agriculture, collects tissue samples used to identify important traits and remove undesirable plants before they are planted in the field.
Credit
Courtesy Isabella Vaughn
Journal
HortScience
Method of Research
Data/statistical analysis
Article Title
Diagnostic KASP Markers for Flower Sex and Stenospermocarpic Seedlessness in Diverse Vitis, Muscadinia, and Wide Hybrid Populations
Pollinator-friendly gardens don’t have to sacrifice style
New study finds some cultivated flowers can support bees and butterflies
image:
A golden northern bumble bee visits a foxglove beardtongue.
view moreCredit: Nick Dorian
For gardeners who love colorful, tidy flower beds, helping pollinators doesn’t have to mean going fully wild.
A new study from plant biologists at Northwestern University and the Chicago Botanic Garden found that some cultivated plants — bred for their vibrant blooms, compact forms and visually appealing uniformity — can still provide meaningful support for bees, butterflies and other pollinators.
Among the tested plants, cultivated black-eyed Susan (Rudbeckia fulgida ‘Goldsturm’) and foxglove beardtongue (Penstemon digitalis ‘Husker Red’) attracted pollinators at similar rates to their wild counterparts, while others, such as R. fulgida ‘American Gold Rush’ and P. digitalis ‘Blackbeard,’ performed less well.
While conventional knowledge often suggests that native wildtype plants are best for pollinators, the new findings reveal a reassuring middle ground. Gardeners don’t have to choose between beauty and ecological value. Instead, a thoughtfully planted mix of wild and cultivated flowers may offer a more approachable starting point for people who are new to pollinator gardening.
The open-access study was published on April 1 in the journal Ecosphere.
“Our findings emphasize that ecological value and aesthetics don’t have to be at odds with each other,” said Chicago Botanic Garden’s Nicholas Dorian, the study’s lead author. “There are many people who might be interested in getting involved in the pollinator gardening movement but feel intimidated. Turning a garden or front yard into a wild space can feel daunting. A key takeaway from our study is that cultivated plants with aesthetic appeal can still bring pollinators into your yard and may be a really nice gateway for people who are on the fence or don’t have time or resources to seek out wildtype plants.”
An expert in residential and urban gardening for pollinator conservation, Dorian is a postdoctoral research associate in the Program in Plant Biology and Conservation, a partnership between Northwestern’s Weinberg College of Arts and Sciences and the Chicago Botanic Garden. Dorian is advised by study co-author Paul CaraDonna, an adjunct associate professor at Weinberg and a conservation scientist at the Chicago Botanic Garden’s Negaunee Institute.
A growing movement
Although pollinator gardens have been around for decades, the movement accelerated in the mid-2000s — sparked by the alarming decline of honeybees. Now, it is a mainstream movement, with millions of pollinator gardens dotting lawns, parks and roadways across the U.S.
“The pollinator garden movement is a somewhat new approach to the conservation of biodiversity,” Dorian said. “In the 20th century, we thought conservation had to take place in big areas away from people — like in national parks or big preserves. But, more recently, we’ve brought conservation back home. That can mean ripping up your lawn to install a native meadow, planting a pot of flowers on your balcony or collaborating with your neighbors to convert the road median into a garden.”
Traditionally, pollinator gardeners have prioritized native, “wildtype” plants — species that grow naturally in the wild without human breeding — and avoid cultivated varieties, or cultivars. Wildtype plants retain their original traits, which were shaped in part by thousands of years of evolution to attract pollinators. Cultivars, on the other hand, are bred not to attract pollinators but to appeal to people. This has led many people to assume that cultivars wouldn’t attract pollinators.
“These days, there is an overwhelming interest in gardening for pollinators,” CaraDonna said. “One of the most frequent questions we’re asked is ‘which plants are best for pollinators?’ Somewhat surprisingly, there’s not a lot of science behind pollinator gardening guidelines, including which plants are best for pollinators.”
From botanic garden to backyard
To help close this gap in knowledge, Dorian, CaraDonna and their collaborators compared how well wildtype plants and cultivars attract pollinators. The study included both controlled experiments at the Chicago Botanic Garden and crowdsourced observations from volunteers across the eastern U.S.
In the controlled experiment, researchers planted four native plant species alongside 13 cultivated varieties in the same plot. Throughout a two-year period, trained ecologists observed each individual plant for 10-minute periods, three times per week. During each observation, they counted the number of insects — including bumble bees, honeybees, butterflies, moths, beetles and others — that visited the flowers’ reproductive features.
To explore whether their results extended beyond a single garden, the research team turned to the public. Through a five-year community science project, volunteers planted the same flowers in backyards, schoolyards and public spaces, and then tracked pollinator visits using the standardized 10-minute observation method.
Not all flowers are equal
The combined results revealed a clear pattern. While the researchers did confirm that wildtypes are consistently the most attractive to insects, cultivars sometimes performed just as well — depending on the variety. Some varieties of black-eyed Susan, beardtongue and aromatic aster attracted pollinators at similar rates to wild plants. But others drew significantly fewer visits.
“None of the plants were completely ignored by insects,” Dorian said. “Wildtypes always had the highest visitation in our study, but some of the cultivars also performed similarly to wildtypes. That means cultivars shouldn’t be dismissed as having no value. That being said, not all cultivars are created equally. Some did underperform compared to the wildtype, and I think that helps to explain why cultivars tend to get a bad reputation among native plant gardeners.”
But even low performers attract more pollinators than lawn grass, which offers virtually no food. That means cultivars, while not perfect substitutes for native plants, can be a useful complement to wildtypes in pollinator gardens. This insight is especially useful because wildtype plants can be difficult to find, while cultivars are widely available at most nurseries and garden centers.
“If you’re trying to attract insects to a green space and all you can find is one of the cultivars that we evaluated, it’ll be certainly better than turf grass,” Dorian said. “It can attract insects and bring them out of hiding.”
A practical path for gardeners
Dorian and CaraDonna emphasize that their study’s findings apply to pollinator gardens and not to ecosystem conservation and restoration projects (where cultivars should not be used). They also underscore that they only studied 13 cultivars and do not have enough information to recommend cultivars that were not included in the study.
“Importantly, none of the cultivars in our study exhibited extra petal production, known as ‘doubled flowers,’” Dorian said. “Those cultivars are best avoided for pollinator-friendly gardens. It’s also important to add that cultivars should never be used for ecological restoration projects. Because cultivars are propagated in a greenhouse, we don’t know how they will interact with wild species.”
Next, the team aims to evaluate a broader range of plant varieties and to better understand which floral traits, such as color and height, drive pollinator preferences. And they hope to continue building support for the pollinator gardening movement.
“We want to empower people to feel they have agency over the future of biodiversity where they live,” Dorian said. “By providing evidence for how anyone can attract and support insects in their own yard, we’re hoping to help keep up the momentum of this really exciting movement to do conservation at home.”
The study, “Evaluating cultivars for pollinator gardens,” was partially supported by the National Science Foundation and The Negaunee Institute for Plant Conservation Science and Action.
An example of a pollinator garden
A bufflehead mason bee visits a foxglove beardtongue.
A longhorn bee visits a New England aster
Credit
Nick Dorian
Journal
Ecosphere
Method of Research
Observational study
Article Title
Evaluating cultivars for pollinator gardens
Article Publication Date
8-Apr-2026
No comments:
Post a Comment