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United States Department of Agriculture

Agricultural Research Service

Research Project: Improving bioenergy and forage plants and production systems for the central U.S.

Location: Grain, Forage & Bioenergy Research

Title: Towards uncovering the roles of switchgrass peroxidases in plant processes

Authors
item Saathoff, Aaron
item Donze, T -
item Palmer, Nathan
item Bradshaw, J -
item Heng-Moss, T -
item Twigg, P -
item Tobias, Christian
item Lagrimini, M -
item Sarath, Gautam

Submitted to: Frontiers in Plant Biotechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 29, 2013
Publication Date: June 19, 2013
Repository URL: http://handle.nal.usda.gov/10113/56933
Citation: Saathoff, A.J., Donze, T., Palmer, N.A., Bradshaw, J., Heng-Moss, T., Twigg, P., Tobias, C., Lagrimini, M., Sarath, G. 2013. Towards uncovering the roles of switchgrass peroxidases in plant processes. Frontiers in Plant Biotechnology. 4:1-12. doi 10.3389/fpls.2013.00202.

Interpretive Summary: An increase in the acreages cropped with bioenergy grasses is likely to increase the incidence insect herbivores that target these plants. Plants have evolved several defensive strategies to counter these herbivores. However, these defensive mechanisms are not well understood in switchgrass. In this study, literature on cell wall lignin formation, and some specific aspects of plant-insect interactions were reviewed. These data pointed to an important role for a specific class of enzymes, called peroxidases in plant defense against herbivory by piercing-sucking insects (hemipterans). The numbers, types and tissue-expression patterns of genes coding for switchgrass peroxidases has been investigated and described in this paper. It is anticipated that these initial studies will as a foundation for more detailed understanding of the molecular and cellular responses of switchgrass to hemipteran pests.

Technical Abstract: Herbaceous perennial plants selected as potential biofuel feedstocks had been understudied at the genomic and functional genomic levels. Recent investments, primarily by the U.S. Department of Energy, have led to the development of a number of molecular resources for bioenergy grasses and related diploid species. These have included the partially annotated genome for switchgrass (Panicum virgatum L.). In its current version, the switchgrass genome contains 65,878 gene models arising from the A and B genomes of this tetraploid grass. The availability of these gene sequences provides a framework to exploit transcriptomic data obtained from next generation sequencing platforms to address questions of biological importance. One such question pertains to discovery of genes and proteins important for biotic and abiotic stress responses, and how these components might affect biomass quality and stress response in plants engineered for a specific end purpose. It can be expected that production of switchgrass on marginal lands will expose plants to diverse stresses, including herbivory by insects. Class III plant peroxidases have been implicated in many developmental responses such as lignification, and in the adaptive responses of plants to insect feeding. Here, we have analyzed the Class III peroxidases encoded by the switchgrass genome, and have mined available transcriptomic datasets to develop a first understanding of the expression profiles of the Class III peroxidases in different plant tissues. Lastly, we have identified switchgrass peroxidases that appear to be orthologs of enzymes shown to play key roles in lignification and plant defense responses to hemipterans.

Last Modified: 10/20/2014