Agriculture already monopolizes 90 percent of global freshwater—yet production still needs to dramatically increase to feed and fuel the earth's growing population. For the first time, scientists have improved how a crop uses water by 25 percent without compromising yield by altering the expression of one gene that is found in all plants, as reported in Nature Communications.
The research is part of the international research project, Realizing Increased Photosynthetic Efficiency (RIPE) that is supported by the Bill & Melinda Gates Foundation, the Foundation for Food and Agriculture Research, and the U.K. Department for International Development.
“This is a major breakthrough,” said RIPE Director Stephen Long, Ikenberry Endowed Chair of Plant Biology and Crop Sciences. “Crop yields have steadily improved over the past 60 years, but the amount of water required to produce one ton of grain remains unchanged—which led most to assume that this factor could not change. Proving that our theory works in practice should open the door to much more research and development to achieve this all-important goal for the future.”
The international team, which included Plant and Microbial Biology Professor Krishna Niyogi, 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.
“These plants had more water than they needed, but that won’t always be the case,” said co-first author Katarzyna Glowacka, a postdoctoral researcher who led this research at the University of Illinois at Urbana-Champaign's Carl R. Woese Institute for Genomic Biology (IGB). “When water is limited, these modified plants will grow faster and yield more—they will pay less of a penalty than their non-modified counterparts.”
The team improved the plant’s water-use-efficiency—the ratio of carbon dioxide entering the plant to water escaping—by 25 percent without significantly sacrificing photosynthesis or yield in real-world field trials. The carbon dioxide concentration in our atmosphere has increased by 25 percent in just the past 70 years, allowing the plant to amass enough carbon dioxide without fully opening its stomata. “Evolution has not kept pace with this rapid change, so scientists have given it a helping hand,” said Long, who is also a professor of crop sciences at Lancaster University.
Four factors can trigger stomata to open and close: humidity, carbon dioxide levels in the plant, the quality of light, and the quantity of light. This study is the first report of hacking stomatal responses to the quantity of light.
PsbS is a key part of a signaling pathway in the plant that relays information about the quantity of light. By increasing PsbS, the signal says there is not enough light energy for the plant to photosynthesize, which triggers the stomata to close since carbon dioxide is not needed to fuel photosynthesis.
This research complements previous work, published in Science, which showed that increasing PsbS and two other proteins can improve photosynthesis and increase productivity by as much as 20 percent. Now the team plans to combine the gains from these two studies to improve production and water-use by balancing the expression of these three proteins.
For this study, the team tested their hypothesis using tobacco, a model crop that is easier to modify and faster to test than other crops. Now they will apply their discoveries to improve the water-use-efficiency of food crops and test their efficacy in water-limited conditions.
“Making crop plants more water-use efficient is arguably the greatest challenge for current and future plant scientists,” said co-first author Johannes Kromdijk, a postdoctoral researcher at the IGB. “Our results show that increased PsbS expression allows crop plants to be more conservative with water use, which we think will help to better distribute available water resources over the duration of the growing season and keep the crop more productive during dry spells.”
Read the article at its source, RIPE's website.Image: Date: Tuesday, March 6, 2018 - 08:15 Legacy: section header item: Date: Friday, March 2, 2018 - 14:15 headline_position: Top Left headline_color_style: Normal headline_width: Long caption_color_style: Normal caption_position: Bottom Left News/Story tag(s): Research News
Scientists at the University of California, Berkeley, have discovered that the same kind of fat cells that help newborn babies regulate their body temperature could be a target for weight-loss drugs in adults.
Brown fat cells, which help mammals regulate their body temperature, work much like muscle cells, the researchers discovered. When the brain sends a signal to brown fat to start burning energy to generate heat, the cells stiffen, which triggers a biochemical pathway that ends with these cells burning calories for heat. The multidisciplinary research team of bioengineers and metabolic researchers teased apart the steps of this pathway and identified a potential way for drugs to switch on brown fat cells.
“We have figured out a new pathway that triggers brown fat tissue to consume calories from fat and sugars and radiate them away as heat,” said Andreas Stahl, professor and chairman of the Department of Nutritional Sciences and Toxicology at Berkeley. “This understanding of how brown fat is activated could unlock new ways to combat obesity.”
The research was published March 6 in the journal Cell Metabolism. The work was funded by the National Institutes of Health and the American Diabetes Association.
When cold, the human body shivers to produce heat in an attempt to maintain a body temperature of 98.6 degrees Fahrenheit. Newborn babies, who can’t yet shiver, have a patch of brown fat between their shoulder blades, and its job is to take in nutrients to burn their energy to produce heat for regulating body temperature. Brown fat cells decrease in number as babies grow up, but adults still have a small number of brown fat cells that are not very active.
Here’s how brown fat works: When the body senses cold, the brain releases norepinephrine, which is detected by a receptor in brown fat cells. A cascade of biochemical signals is then triggered, leading to the production of a protein called Uncoupling Factor-1 (UCP1), which travels into the mitochondria of brown fat cells.
A normal cell uses mitochondria like a battery to perform work. Mitochondria turn nutrients from the diet into energy that is mostly stored in a molecule called ATP. But in brown fat cells, UCP1 short-circuits that battery, causing it to heat up instead of producing ATP. With UCP1 activated in the mitochondria, brown fat cells soak up fat and sugars from the diet and burn them for heat in the mitochondria.
Previous research found that brown fat shares some characteristics with muscle, particularly proteins called myosin, which are little motors that perform work. In muscle, myosin contracts the cells, but no one knew what myosin did in brown fat cells.
To find out, the researchers stimulated brown fat and measured how much the cell flexed by measuring the increase in tension in the cell. They found that the cells became roughly twice as stiff when stimulated. Then the researchers disabled the muscle-like myosin in brown fat cells and found that the cells became significantly softer, with their stiffness reduced by about a factor of two.
“Our finding that the muscle-like myosin is responsible for stiffening brown fat cells was really unexpected, no one has ever observed that,” Stahl said.
“This study offers a remarkable example of how mechanical and other physical forces can influence physiology and disease in powerful, unexpected ways,” said Sanjay Kumar, Berkeley professor of bioengineering and a co-author of the study. “We hope that our work will aid in the design of therapeutic biomaterials and other technologies geared towards enhancing brown fat function.”
The study found that UCP1’s activity is directly tied to the increase in cell tension. The scientists then relieved the tension in activated brown fat cells and found that caused a 70 percent reduction in UCP1, so the cells generate less heat. The researchers then identified molecules in the cell that respond to increased tension to trigger the activation of UCP1. In experiments in mice, they disrupted these molecules and found that the brown fat cells lost their function and physically looked more like white fat cells, where the body stores excess energy.
“We found that cell stiffening really plays a big role in the function of brown adipocytes,” Stahl said.
The researchers used a drug to trigger increased tension in brown fat cells and found that the concept of activating tension can lead to burning calories, but much more work is needed to identify the right chemical compound that could do this effectively.
“Now that we better understand how brown fat cells work, we can think about ways to stimulate muscle-like myosin in brown fat to increase thermogenesis and burn calories,” Stahl said. “Drugs to stimulate muscle-like myosin in existing brown fat would probably create more active brown fat cells in adults.”Monday, March 5, 2018 - 11:30 byline: By Brett Israel, UC Berkeley Media Relations Legacy: section header item: Date: Monday, March 5, 2018 - 11:30 headline_position: Top Left headline_color_style: Normal headline_width: Long caption_color_style: Normal caption_position: Bottom Left News/Story tag(s): Research News
There’s no change at the top of this year’s list in the QS World University Rankings for environmental sciences, with UC Berkeley ranked number one for the fourth year in a row. Congratulations to all those in the College of Natural Resources' community—and across the University—whose work has contributed to this recognition!
The QS World University Rankings by Subject are based upon academic reputation, employer reputation, and research impact.Thursday, March 1, 2018 - 15:30 Legacy: section header item: Date: Thursday, March 1, 2018 - 15:30 headline_position: Top Left headline_color_style: Normal headline_width: Long caption_color_style: Normal caption_position: Bottom Left
MCB Professor Nipam Patel's research on butterfly development was featured in a video by the California Academy of Sciences. Patel's lab is aiming to understand how butterflies develop their dazzling wing patterns and colors.