Genetic screen identifies mutations that impact green foxtail panicle formation.
Field of Setaria viridis growing in western Nebraska. In Nature Plants, researchers use S. viridis to identify the inflorescence mutant, sparse panicle 1. A mutation in the maize ortholog conditions a very similar panicle defect, demonstrating the utility of S. viridis for gene discovery in the panicoids. (Pu Huang)
The Science
Through deep sequencing of the model grass green foxtail (Setaria viridis), researchers pinpointed a gene critical for the development of flowers that give rise to the grain. Using this information, a homologous gene in maize was identified as playing a similar role highlighting the utility of S. viridis as a model crop.
The Impact
Maize, an important food and bioenergy crop, has been limited in the progress of gene discovery due to its large and complex genome. Recently, S. viridis has been proposed as a model crop for maize, but the grass is already a model system for the candidate bioenergy feedstocks switchgrass and Miscanthus. In a new study, researchers screening for mutants of the model grass green foxtail identified several mutations that disrupt the regular pattern of panicle development. The panicle is the spear-shaped flowering cluster at the tip of each branch necessary for reproduction.
Summary
Setaria species, among them green foxtail (S. viridis) and foxtail millet (S. italica), are related to several candidate bioenergy grasses including switchgrass and Miscanthus and serve as grass model systems to study grasses that photosynthetically fix carbon from CO2 through a water-conserving (C4) pathway. The genomes of both green foxtail and foxtail millet have been sequenced and annotated through the DOE JGI’s Community Science Program. A team led by Tom Brutnell at the Donald Danforth Plant Science Center and including researchers at the U.S. Department of Energy Joint Genome Institute (DOE JGI), a DOE Office of Science User Facility, reported in Nature Plants, that they had identified genes that may play a role in flower development on the panicle of green foxtail.
The team identified four recessive mutants, tagged spp1 through spp4, that lead to panicles with reduced and uneven flower clusters. Focusing on the spp1 mutation, they performed deep sequencing to specifically locate the genes that cause the mutation, narrowing their search down to a 1-million base sequence. They ultimately identified the SvAUX1 gene in green foxtail as one critical for flower cluster development in green foxtail. Panicle development is critical for determining grain yield that is crucial to food crops as well as candidate crops for producing renewable and sustainable fuels. A homologous gene in maize was identified as playing a similar role, illustrating the value of model systems in finding genes involved in important properties in potential bioenergy-relevant plants.
BER Contacts
Daniel Drell, Ph.D.
Program Manager
Biological Systems Sciences Division
Office of Biological and Environmental Research
Office of Science
US Department of Energy
daniel.drell@science.doe.gov
Pablo Rabinowicz, Ph.D.
Program Manager
Biological Systems Sciences Division
Office of Biological and Environmental Research
Office of Science
US Department of Energy
Pablo.Rabinowicz@science.doe.gov
PI Contacts
Jeremy Schmutz
Plant Program Head
DOE Joint Genome Institute
jschmutz@hudsonalpha.com
Thomas Brutnell
Donald Danforth Plant Science Center
tbrutnell@danforthcenter.org
Funding
This work was conducted by the U.S. Department of Energy’s (DOE) Joint Genome Institute, a DOE Office of Science user facility (contract number DE-AC02-05CH11231). This work was also supported by a Department of Energy grant to T. Brutnell (DE-SC0008769), and a National Science Foundation grant to E.A. Kellogg (IOS-1413824).
Publications
P. Huang, H. Jiang, C. Zhu, K. Barry, J. Jenkins, L. Sandor, J. Schmutz, M.S. Box, E.A. Kellogg, and T.P. Brutnell. “Sparse panicle1 is required for inflorescence development in Setaria viridis and maize.” Nat. Plants. (2017) DOI: 10.1038/nplants.2017.54