Posts Tagged: Kearney
As sorghum plants cope with drought conditions, the plants' roots and adjoining microbial communities are communicating in a chemical language that appears to improve the plants' chances under water stress.
“It's amazing,” said Peggy Lemaux, UC Cooperative Extension specialist. “We know there are lots of microbes in the soil and, for the most part, ones in the surrounding soil stayed the same under drought conditions. We only saw changes in those microbes closely associated with the roots.”
The role of drought in restructuring the root microbiome was the first published discovery to come out of a sweeping drought research project underway since 2015 in the fields at UC Kearney Research and Extension Center in Parlier. The five-year study, funded with a $12.3 million grant from the Department of Energy, aims to tease out the genetics of drought tolerance in sorghum and its associated microbes. Using sorghum as a model, scientists hope the research will help them understand and improve drought tolerance in other crops as well.
The new research results from the lab of USDA's Devin Coleman-Derr at UC Berkeley, published April 16, 2018, in the Proceedings of the National Academy of Sciences, document the fate of microbes associated with sorghum roots under three distinct irrigation regimens. Because the San Joaquin Valley generally sees no rain during the growing season, it is the ideal place to mimic drought conditions by withholding irrigation water.
All plots received a pre-plant irrigation to initiate growth. In the control plots, sorghum was irrigated normally, with weekly watering through the season. In the plot simulating pre-flowering drought stress, the plants received no additional water until flowering, about halfway through the season. The third treatment was watered normally until it flowered, and then water was cut off for the rest of the season.
Beginning when the plants emerged, the scientists collected samples from each plot on the same day and time each week for 17 weeks. In a mini, in-field laboratory, roots, rhizosphere (zone surrounding the root), leaves and soil samples from 10 plants in each plot were immediately frozen and transported to Berkeley, where they were disseminated to collaborators, who investigated the plant and microbial responses at the molecular level.
“When a sorghum plant is subjected to drought, it starts sloughing off metabolites, nutrients and amino acids from the roots. The compounds appear to communicate to the neighboring microbial community that the plant is under stress,” Lemaux said. “That selects out a certain population of microbes. Certain types of microbes increase, others go away. When you add water back, the microbial community returns to its pre-drought population in just a few days.”
The researchers cultured two specific microbes that were enriched in the rootzone under drought conditions. They coated sorghum seeds with the microbes and planted them under drought conditions in a growth chamber. This treatment encouraged the plant to grow more roots.
“The microbes appear to improve plant growth during drought,” Lemaux said. “Those microbes appear to be helping plants survive drought. We didn't know that was happening before we got these results.”
Lemaux said the research might lead to future field use of the research breakthrough.
“A lot of companies are interested in the microbiome,” she said. “Some are already selling microbes to coat seeds.”
Summaries of presentations from the 2016 Organic Agriculture Research Symposium (OARS) held in Pacific Grove are now available online at http://eorganic.info/node/16778. Many of the workshops and keynote presentations were recorded live and may be viewed via the eOrganic YouTube channel.
“We are making these presentations available free online to extend the reach of all the valuable information shared at the symposium,” said Jeff Dahlberg, director of the UC Kearney Agricultural Research and Extension Center. “We're now planning the 2017 symposium and it will build on the cutting edge research shared by scientists this year.”
In the opening address, president of Organics International, André Leu, said organic agriculture offers the promise of a future to produce and distribute food and other farm products in a healthy, economically sound, truly sustainable and fair way. He called the current state of organic agriculture “Organic 3.0.”
“This is a concept we put out a year ago and it is resonating around the world,” Leu said. Organic 1.0 dates back to the 1920s and represents organic farming founders and visionaries, he said. Organic 2.0, beginning in the 1970s, represents the establishment of private standards, public regulations and global recognition. The current stage of organic farming is a time for market reinvention, widespread conversion and performance improvement.
Financial support for the 2016 OARS was provided by the USDA National Institute for Food and Agriculture Organic Research and Extension Initiative and the Gaia Fund.
"The OARS conference was very successful in bringing national and international scholars and farmers together to present findings about the latest research and how it is advancing organic farming and ranching," said Diana Jerkins, OARF research director. "OFRF will continue to encourage and participate in events such as these to ensure current research, education, and extension efforts are widely disseminated."
Organic Farming Research Foundation is a non-profit foundation that works to foster the improvement and widespread adoption of organic farming systems. OFRF cultivates organic research, education, and federal policies that bring more farmers and acreage into organic production.
The UC Kearney Agricultural REC is one of nine UC Agriculture and Natural Resources research and extension centers across the state of California. Ten acres at the 330-acre center are certified organic and available for organic research.