Posts Tagged: sorghum
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.”
As the alfalfa hay harvest season wraps up and we get in gear to attend the November 2017 Western Alfalfa and Forage Symposium in Reno, NV, we're...
Last year many forage sorghum fields were heavily infested and damaged by Sugarcane Aphid (SCA) (Figure 1) – Melanaphis sacchari –...
PCA's and field scouts, be on the lookout with your hand lenses this late fall for flea beetles in recently emerged small grains that are planted...
Adult Pale-striped Flea Beetle
Flea beetle enlarged femur
Flea beetle on wheat seedling
Flea beetle feeding damage to edge of wheat field
Early flea beetle feeding damage on wheat seedlings
Later flea beetle feeding damage on wheat seedlings
A team of researchers has received a $5 million grant from the U.S. Department of Agriculture to find new ways to combat Johnsongrass, one of the most widespread and troublesome agricultural weeds in the world.
“Johnsongrass is a huge problem,” said Jeff Dahlberg, UC Cooperative Extension sorghum specialist and director of the UC Kearney Agricultural Research and Extension Center in Parlier, Calif. “It impacts many different crops and is very hard to control.”
Dahlberg is part of the team that includes scientists from Virginia, Kansas, North Carolina, Texas and Georgia. Andrew Paterson, director of the Plant Genome Mapping Laboratory at the University of Georgia, Athens, is the lead investigator.
The naturalization of Johnsongrass across much of the U.S. has also allowed the plant to develop attributes — such as cold and drought tolerance, resistance to pathogens and the ability to flourish in low-fertility soils — that make it particularly difficult to control. Adding to the challenge is the adoption of herbicide-resistant crops around the world.
“Herbicide-resistant crops have been associated with a dramatic increase in herbicide-resistant weeds,” Patterson said. “With 21 genetically similar but different types of Johnsongrass known to be resistant to herbicides, it will only become more problematic in the future.”
Over the course of their five-year project, the researchers will work to better understand the weed's capabilities and the genes that make Johnsongrass so resilient. Johnsongrass [Sorghum halepense] is closely related to sorghum [Sorghum bicolor (L.) Moench], a healthy gluten-free grain, animal feed and biofuel crop. Lessons learned from the Johnsongrass research may lead to strategies to improve sorghum.
For his part, Dahlberg plans to use the global information system (GIS) to map the locations of Johnsongrass in California to better record its distribution in the state and to help understand how it spread into California by relating it to other populations of johnsongrass in the U.S.
“Ideally, we will use an app to map, identify, manage, and catalog populations that have developed different traits – such as susceptibility to plant disease, ability to host a particular insect, or resistance to herbicides,” he said.
This information may lead to new management strategies that target and curb its growth, providing farmers with more options to combat the invasive plant. The researchers also hope that learning more about the fundamental structures that give Johnsongrass its unusual resilience will pave the way for new genetic tools to improve useful plants, such as sorghum.
Other researchers working on this project are Jacob Barney, Virginia Tech; C. Michael Smith, Kansas State University; Wesley Everman, North Carolina State University; Marnie Rout, University of Texas, Temple; and Clint Magill and Gary Odvody, Texas A&M University.