Principal Investigator, Andrea Eveland, Ph.D., associate member at the Donald Danforth Plant Science Center, will lead a multi-institutional project to deepen the understanding of sorghum, a versatile bioenergy crop, and its response to drought. The U.S. Department of Energy (DOE) Genome-Enabled Plant Biology program supports the three-year $2.7 million project for the Determination of Gene Function program.
Sorghum is the fifth most widely grown cereal crop worldwide and the third largest in the U.S. It has natural resilience to drought stress and excessive heat, which is attractive for developing bioenergy feedstocks for production on marginal lands. Eveland's project explores the gene networks underlying this remarkable stress resilience in sorghum and seeks to define the functions of critical genes and how they are regulated. Drought tolerance is a complex trait and understanding its regulation in the broader context of the whole plant and its environment will require advanced approaches in genetics, genomics, phenotyping and gene editing.
There is extraordinary genetic diversity underlying sorghum's adaptation to stressful environments, and we want to tap into this in a precise way to inform engineering and breeding strategies for future climates. We have little understanding of what most of the 30,000+ genes in the sorghum genome do and whether functionally conserved genes have unique control mechanisms in drought-adapted sorghum -- this information could help efforts to make other crops more stress resilient too."
Andrea Eveland, Ph.D., Associate Member, Donald Danforth Plant Science Center
Eveland and collaborators will leverage this incredible genetic diversity found in sorghum to examine how responses at the molecular level, such as gene expression, lead to whole-plant morphological changes in response to drought stress. Advanced genomics and gene editing methodologies will be used to help guide predictions of gene function in sorghum. In addition to genes, the "non-functional" genome space comprising the sequences that control gene regulation will be investigated.
To assess whole-plant morphological and physiological responses to drought in real-time, high-resolution, sensor-based field phenotyping will be conducted on a diverse panel of sorghum plants throughout their entire growth cycle, from seedling establishment to harvest, and all those data will be analyzed to link phenotype with genotype.
The research project will leverage a 30-ton robotic field-based phenotyping infrastructure at the University of Arizona's Maricopa Agricultural Center, which DOE ARPA-E funded in the TERRA-REF project led by Todd Mockler, Ph.D., Geraldine and Robert Virgil Distinguished Investigator at the Danforth Center, who is also a collaborator on the project.
"The Maricopa site provides a unique and exceptional opportunity to conduct managed drought stress trials due to the hot and dry environment and the capability for controlled irrigation," said Mockler. The field scanner system collects high-resolution sensor data for crop traits throughout the growing season."
Joining Eveland and Mockler as collaborators on this project are Duke Pauli, Ph.D., University of Arizona, and Brian Dilkes, Ph.D., Purdue University.
State-of-the-art phenotyping data analytics pipelines have been developed as part of other DOE-funded initiatives through the Danforth Center and Pauli's team at the University of Arizona. They will be used to extract information on physical traits, including multi-dimensional attributes and those not immediately visible to the naked eye, such as light reflectance.
"I believe this is a very impactful project as it is directly relevant to the effects of climate change that we are witnessing both here in Arizona as well as nationally," said Pauli, assistant professor in the School of Plant Sciences at the University of Arizona. "The information and knowledge gained from this work have the capacity to help guide plant improvement as it relates to developing and delivering more climate resilient cultivars that growers desperately need."
The project also leverages chemically-mutagenized sorghum populations in different genetic backgrounds developed at Purdue University. Each plant carries one or more changes in its DNA compared to un-mutagenized controls, and each mutant's genome has been sequenced so that mutations in specific genes can be linked with the observed phenotypes. This enables a classic method called 'forward genetics' to be used for gene function analysis, where the mutagenized sorghum plants are screened for altered physical characteristics (phenotypes) in response to drought.
"By building populations of mutant families, we can perform a novel kind of screen that evaluates the same genetic changes in different degrees of drought under the field scanner and at multiple field sites," said Dilkes, professor in the Department of Biochemistry at Purdue. "This can identify novel mutations that provide drought stress tolerance and help us to unlock the secret of how plant genotypes interact with their environment".
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