Nearly everyone on Earth is familiar with corn. Literally.
Around the world, each person eats an average of 70 pounds of the grain each year, with even more grown for animal feed and biofuel. And as the global population continues to boom, increasing the amount of food grown on the same amount of land becomes increasingly important.
One potential solution is to develop crops that perform better in cold temperatures. Many people aren’t aware that corn is a tropical plant, which makes it extremely sensitive to cold weather. This trait is problematic in temperate climates where the growing season averages only 4 or 5 months – and where more than 60% of its 1.6 trillion pound annual production occurs.
A chilling-tolerant strain could broaden the latitudes in which the crop could be grown, as well as enable current farmers to increase productivity.
A group of researchers led by David Stern, president of the Boyce Thompson Institute, have taken a step closer to this goal by developing a new type of corn that recovers much more quickly after a cold snap. Stern is also an adjunct professor of plant biology in Cornell University’s College of Agriculture and Life Sciences.
The research is described in a paper published online in Plant Biotechnology Journal.
“In the field, chilling stress happens most often in the spring when cold temperatures combine with strong sunlight, causing plants to bleach,” Stern said. “So a more chilling-tolerant corn could help farmers plant earlier in the year with confidence that their crop would survive a cold spell and bounce back quickly once the weather warmed up again.”
This work built on research published in 2018, which showed that increasing levels of an enzyme called Rubisco led to bigger and faster-maturing plants. Rubisco is essential for plants to turn atmospheric carbon dioxide into sugar, and its levels in corn leaves decrease dramatically in cold weather.
In the latest study, Stern and colleagues grew corn plants for three weeks at 25°C (77°F), lowered the temperature to 14°C (57°F) for two weeks, and then increased it back up to 25°C.
“The corn with more Rubisco performed better than regular corn before, during and after chilling,” said Coralie Salesse-Smith, the paper’s first author. “In essence, we were able to reduce the severity of chilling stress and allow for a more rapid recovery.” Salesse-Smith was a Cornell PhD candidate in Stern’s lab during the study, and she is now a postdoctoral researcher at the University of Illinois.
Indeed, compared to regular corn, the engineered corn had higher photosynthesis rates throughout the experiment, and recovered more quickly from the chilling stress with less damage to the molecules that perform the light-dependent reactions of photosynthesis.
The end result was a plant that grew taller and developed mature ears of corn more quickly following a cold spell.
Steve Reiners, a co-team leader for Cornell Cooperative Extension’s vegetable program, says that sweet corn is a major vegetable crop in New York, worth about $40-$60 million annually. He notes that many New York corn growers plant as soon as they can because an early crop commands the highest prices of the season.
“Many corn growers in New York plant early under protective plastic sheets to increase soil temperatures, which is expensive. Chilling-tolerant corn could allow farmers to remove that plastic sooner,” Reiners said. “This would expose the plants to additional sunlight, potentially enabling them to mature earlier in the season and get farmers those higher prices.”
Reiners, who was not involved in the study, is also a professor of horticulture at Cornell.
“The corn we developed isn’t yet completely optimized for chilling tolerance, so we are planning the next generation of modifications,” said Stern. “For example, it would be very interesting to add a chilling-tolerant version of a protein called PPDK into the corn and see if it performs even better.”
The researchers believe their approach could also be used in other crops that use the C4 photosynthetic pathway to fix carbon, such as sugar cane and sorghum.
Co-authors on the paper include researchers from The Australian National University in Canberra.
Read the paper: Plant Biotechnology Journal
Article source: Boyce Thompson Institute
Author: Aaron J. Bouchie
Image credit: Jason Koski/Brand Communications
By Mathew Reynolds, Wheat Physiologist at, CIMMYT
First post of our “Global Collaboration” series
Wheat is the most widely grown crop in the world, currently providing about 20 percent of human calorie consumption. However, demand is predicted to increase by 60 percent within just 30 years, while long-term climate trends threaten to reduce wheat productivity, especially in less developed countries.
For over half a century, the International Wheat Improvement Network (IWIN), coordinated by CIMMYT, has been a global leader in breeding and disseminating improved wheat varieties to combat this problem, with a major focus on the constraints of resource poor farmers.
Two complementary networks — the Heat and Drought Wheat Improvement Consortium (HeDWIC) and the International Wheat Yield Partnership (IWYP) — are helping to meet the future demand for wheat consumption through global collaboration and technological partnership.
By harnessing the latest technologies in crop physiology, genetics and breeding, network researchers support the development of new varieties that aim to be more climate resilient, in the case of HeDWIC and with higher yield potential, in the case of IWYP.
These novel approaches to collaboration take wheat research from the theoretical to the practical and incorporate science into real-life breeding scenarios. Methods such as screening genetic resources for physiological traits related to radiation use efficiency and identifying common genetic bases for heat and drought adaptation are leading to more precise breeding strategies and more data for models of genotype-by-environment interaction that help build new plant types and experimental environments for future climates.
IWYP addresses the challenge of raising the genetic wheat yield potential of wheat by up to 50 percent in the next two decades. Achieving this goal requires a strategic and collaborative approach to enable the best scientific teams from across the globe to work together in an integrated program. TheIWYP model of collaboration fosters linkages between ongoing research platforms to develop a cohesive portfolio of activities that maximizes the probability of impact in farmers’ fields IWYP research uses genomic selection to complement the crossing of complex traits by identifying favorable allele combinations among progeny. The resulting products are delivered to national wheat programs worldwide through the IWIN international nursery system.
Recently, IWYP research achieved genetic gains through the strategic crossing of biomass and harvest index — source and sink — an approach that also validates the feasibility of incorporating exotic germplasm into mainstream breeding efforts.
In the case of HeDWIC, intensified — and possibly new — breeding strategies are needed to improve the yield potential of wheat in hotter and drier environments. This also requires a combined effort, using genetic diversity with physiological and molecular breeding and bioinformatic technologies, along with the adoption of improved agronomic practices by farmers. The approach already has proof of concept in the release and adoption of three heat and drought tolerant lines in Pakistan.
It is imperative to build increased yield and climate-resilience to into future germplasm in order to avoid the risk of climate-related crop failure and to maintain global food security in a warmer climate. Partnerships like HeDWIC and IWYP give hope to meeting this urgent food security challenge.
Further readings:
https://www.hedwic.org/resources.htm
https://royalsocietypublishing.org/doi/full/10.1098/rspb.2012.2190
An economist’s perspective on plant sciences: Under-appreciated, over-regulated and under-funded
