Wednesday, August 20, 2025

 

Corn root traits evolved with both human-driven, natural environmental changes


Study shows plants adapted to farming and irrigation with root changes that helped corn adjust to low nitrogen and deeper water, making them key to the success of its domestication




Penn State

evolution of maize root types 

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This figure from the paper shows the evolution of root types from teosinte to modern corn over the last 10 000 years, simulated using the modeling program OpenSimRoot, which was developed by scientists in Penn State's College of Agricultural Sciences. 

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Credit: Penn State





UNIVERSITY PARK, Pa. — Corn was domesticated from its ancestor teosinte in central Mexico beginning about 9,000 years ago by humans selectively breeding the wild plant, transforming its small, hard-shelled kernels into the large, palatable ears of corn we know today. Over the centuries, root traits of corn — now the most widely planted crop in the U.S., and second globally (by acreage) — evolved in response to both changing environmental conditions and human agricultural practices. Because the role of roots in crop domestication in response to shifting circumstances remains unclear — and because it may be relevant to the present when a warming climate is stressing corn and other crops — a team of researchers led by Penn State plant scientists conducted a study to understand how root traits evolved during corn domestication.

The researchers examined DNA from ancient corn plants and analyzed paleobotanical evidence — fossils of ancient plants as well as pollen and chemical signatures — that provide insights into the history of plant life to see how corn roots evolved. They also analyzed how prehistoric atmospheric carbon dioxide levels and human activity influenced these traits. Considering all these factors, they modeled corn root growth and evolution using the OpenSimRoot Model, a computer program designed to simulate crop response to soil conditions, developed in Penn State’s College of Agricultural Sciences. The team recently reported their findings in New Phytologist.

The researchers reported that three major root changes occurred as part of the transformation from teosinte to corn: Fewer nodal roots — shallow roots that grow from the stem base; development of multiseriate cortical sclerenchyma — thick-walled cells in the root that help roots penetrate deeper soils, that was previously discovered by Penn State researchers; and more seminal roots — early-developing roots that help seedlings access nutrients.

“We reconstructed the root phenotypes of corn and teosinte, as well as the environments of the Tehuacán Valley — one of the oldest regions of corn domestication — over the last 18,000 years using a combination of ancient DNA, paleobotany and functional-structural modeling to reconstruct how root traits evolved over time,” said team leader Jonathan Lynch, distinguished professor of plant nutrition, senior author on the study. “The research suggests that root phenotypes that enhance plant performance under nitrogen stress were important for corn adaptation to changing agricultural practices.”

The study traced the following timeline of root trait evolution, according to study first author Ivan Lopez-Valdivia, who earned a doctorate in Plant Science from Penn State in 2024:

— 12,000–8,000 years ago: Carbon dioxide levels rose, favoring deeper root systems. This supported the reduction in nodal roots and appearance of multiseriate cortical sclerenchyma, which help roots grow deeper and access water/nutrients in drier soils.

— By 6,000 years ago: Irrigation was introduced, changing nitrogen availability — less in the topsoil, more in deeper layers. That further reduced nodal roots and presence of multiseriate cortical sclerenchyma became more useful in accessing this subsoil nitrogen.

— Around 3,500 years ago: More seminal roots emerged. Seminal roots are the initial root system that develops from a seed upon germination, playing a crucial role in supporting the seedling’s early growth by absorbing water and nutrients. This coincided with agricultural intensification, population growth and soil degradation — conditions that made early root development more important for survival.

Although the researchers looked far back into time in conducting their study, Lynch suggested the findings may have implications for the future because corn is one of the most important global crops and the climate is changing, with carbon dioxide increasing and soils changing.

“We looked at DNA from ancient corn plant specimens and used environmental data from soil cores that archeologists have generated, put it all together and said, ‘Okay, when corn was originally domesticated, we changed the environment,” he explained. “The amount of carbon dioxide in the atmosphere was changing, and the plant had to develop a different kind of root system. That’s not only interesting historically — because that’s how we got modern corn — but it also gives some guidance as to what we can do with corn roots in the future to make them better adapted to developing conditions.”

Contributing to the research were Ruairidh Sawers, Penn State associate professor of plant response to abiotic stress; Miguel Vallebueno-Estrada, postdoctoral scholar, Swedish University of Agricultural Sciences; Harini Rangarajan, postdoctoral scholar at the University of Illinois; Kelly Swarts, Gregor Mendel Institute of Molecular Plant Biology, Max F. Perutz Laboratories; Bruce Benz, professor of biology, Texas Wesleyan University; Michael Blake, professor and head of the Anthropology Department at the University of British Columbia; Jagdeep Singh Sidhu, former postdoctoral scholar in plant science at Penn State, now assistant professor of crop physiology at South Dakota State University; Sergio Perez-Limon, doctoral candidate in plant science at Penn State; and Hannah Schneider, leader of the Genetics and Physiology of Root Development research group at the Leibniz Institute of Plant Genetics and Crop Plant Research, also a professor at the Georg-August-Universität, Göttingen, Germany.

This project received funding from the Foundation for Food and Agriculture Research, the U.S. Department of Agriculture’s National Institute of Food and Agriculture, the National Science Foundation, the Social Sciences and Humanities Research Council of Canada, and the European Union's Framework Programme for Research and Innovation Horizon 2020.

Plant biologist Lucia Strader joins Salk faculty to study plant growth signaling




Salk Institute
Lucia Strader 

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Lucia Strader

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Credit: Salk Institute





LA JOLLA (Aug 20, 2025)—The Salk Institute will welcome plant biologist Lucia Strader as a new professor and holder of the Howard H. and Maryam R. Newman Chair in Plant Biology in October 2025. Strader is an internationally recognized leader in plant hormone biology who was previously based at Duke University.

Strader’s lab at Salk will explore how plants sense and integrate environmental cues to shape their growth and development. Her work will advance our fundamental understanding of plant biology and help Salk’s Harnessing Plants Initiative design more resilient crop varieties that can thrive in changing environments.

“Lucia is a world expert in decoding the molecular language plants use to interpret and interact with their environment,” says Salk President Gerald Joyce. “Her innovative, multidisciplinary approach will strengthen Salk’s ongoing efforts to address some of the most pressing agricultural and environmental challenges of our time.”

Humans, like most animals, have very standardized developmental timelines—each transition from infant to child to adult is largely predetermined by our genetic code. But plants are much more flexible. A seed can stay a seed until the conditions are right to sprout; a flower won’t bloom without enough sunlight; a seasonal crop can stay in suspended youth or enter old age with a slight shift in temperature.

At the center of this adaptability is auxin, a hormone that regulates nearly every aspect of plant development—from the timing of leaf growth to the number of petals on a flower. Strader studies how auxin and its molecular partners respond to environmental changes, such as rising temperatures or shifting soil nutrients. Her multidisciplinary approach combines techniques from plant physiology, genetics, molecular biology, biochemistry, structural biology, biophysics, systems biology, and synthetic biology to understand the mechanisms of auxin regulation.

In addition to her ongoing breakthroughs in basic science, Strader is committed to translating this research into field-ready solutions. Her team will use their insights on auxin signaling to engineer plants that can withstand extreme weather, use nutrients more efficiently, and produce reliable yields despite environmental stress. Her findings are already supporting the creation of crops that can pollinate under higher nighttime temperatures and survive with less artificial nitrogen fertilization. The move to Salk will help expand her work in both fundamental and applied research areas.

“Salk has something that can’t be found in other places,” says Strader. “The Institute has a uniquely focused mission that allows its faculty to move science forward with fewer distractions. I’m excited to work with colleagues who share a genuine interest and dedication to pushing the boundaries of knowledge and making a real-world impact.”

Strader studied agronomy at Louisiana State University before earning her PhD in molecular plant sciences at Washington State University and completing her postdoctoral training in biochemistry and cell biology at Rice University. She has received numerous honors, including a fellowship with the American Association for the Advancement of Science and the National Science Foundation’s Early Faculty Career Development Award. She has also been named one of 25 Inspiring Women in Plant Biology by the American Society of Plant Biologists.

About the Salk Institute for Biological Studies:

Unlocking the secrets of life itself is the driving force behind the Salk Institute. Our team of world-class, award-winning scientists pushes the boundaries of knowledge in areas such as neuroscience, cancer research, aging, immunobiology, plant biology, computational biology, and more. Founded by Jonas Salk, developer of the first safe and effective polio vaccine, the Institute is an independent, nonprofit research organization and architectural landmark: small by choice, intimate by nature, and fearless in the face of any challenge. Learn more at www.salk.edu.


Updated lab guide equips researchers with modern tools to identify plant pathogens




American Phytopathological Society
Laboratory Guide for Identification of Plant Pathogenic Bacteria, Fourth Edition 

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Cover of Laboratory Guide for Identification of Plant Pathogenic Bacteria, Fourth Edition

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Credit: © The American Phytopathological Society




A trusted and essential resource for more than four decades, Laboratory Guide for Identification of Plant Pathogenic Bacteria returns in a fully updated fourth edition. This guide remains the most authoritative reference for plant pathologists, diagnosticians, and students who need to accurately identify bacterial plant pathogens using both conventional and cutting-edge methods.

Each chapter is authored by leading experts and provides a holistic, comprehensive overview of the genus or genera, including characteristics useful for identification, isolation techniques, and molecular, serological, biochemical, and other assays for identifying phytobacteria. This updated edition provides simplified identification methods, detailed protocols, color photographs, and a list of semiselective agar media for bacterial isolation. Whether you are an experienced researcher or new to plant pathology, this guide offers the essential tools and knowledge to tackle today’s diagnostic challenges.

This comprehensive volume provides:

  • Thorough coverage of more than 30 genera, including 11 not covered in previous editions, such as DickeyaLonsdaleaRobbsiaRhizorhabdus, and Candidatus Liberibacter
  • Step-by-step protocols for isolation, culturing, and pathogenicity testing of bacterial strains
  • Detailed diagnostic approaches—including molecular, serological, biochemical, and real-time PCR assays—to assist in genus- and species-level identification
  • Insightful context on evolving bacterial taxonomy, including the integration of whole genome sequencing and average nucleotide identity in modern species classification
  • Two foundational chapters on bacterial taxonomy and initial identification of common genera

Laboratory Guide for Identification of Plant Pathogenic Bacteria, Fourth Edition is dedicated to Norman W. Schaad, the driving force behind the first two editions and lead editor of the third. Schaad was an excellent scientist with a passion for accurate identification of bacterial plant pathogens as well as a friend to many in the field.

This title was published by APS PRESS, the publishing imprint of The American Phytopathological Society, a nonprofit, international organization that adv​ances the science and practice of plant health management in agricultural, urban, and forest settings. The Society was founded in 1908 and has grown from 130 charter members to more than 3,500 scientists and practitioners worldwide.


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