Skip to main content
ARS Home » Plains Area » Temple, Texas » Grassland Soil and Water Research Laboratory » Research » Publications at this Location » Publication #294733
Title: Integrating transcriptional, metabolomic, and physiological responses to drought stress and recovery in switchgrass (Panicum virgatum L.)

Author
item MEYER, ELI - Oregon State University
item ASPINWALL, MICHAEL - Western Sydney University
item LOWRY, DAVID - University Of Texas
item PALACIO-MEJIA, JUAN DIEGO - University Of Texas
item LOGAN, TIERNEY - University Of Texas
item Fay, Philip
item JUENGER, THOMAS - University Of Texas

Submitted to: BMC Genomics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/5/2014
Publication Date: 6/29/2014
Publication URL: http://handle.nal.usda.gov/10113/5852149
Citation: Meyer, E., Aspinwall, M.J., Lowry, D.B., Palacio-Mejia, J., Logan, T.L., Fay, P.A., Juenger, T.E. 2014. Integrating transcriptional, metabolomic, and physiological responses to drought stress and recovery in switchgrass (Panicum virgatum L.). Biomed Central (BMC) Genomics. 15(527):1-15. http://www.biomedcentral.com/1471-2164/15/527.

Interpretive Summary: Switchgrass (Panicum virgatum L.) is an important grass species native to North America. It is also an important bioenergy crop. However, drought may limit the productivity of switchgrass for bioenergy use. In this study we conducted a detailed investigation of how switchgrass responds to drought. We documented how different genes turn off and on depending on how much water is available to switchgrass plants, and we determined how different genes are associated with plant growth and water use. These results provide a foundation for understanding switchgrass response to drought, and will help guide the development of drought tolerant switchgrass grass varieties. These results improve our understanding of plant responses to drought and will help improve switchgrass bioenergy production.

Technical Abstract: Switchgrass (Panicum virgatum) is a perennial C4 grass widely studied in the context of biofuel production. Although the potential to grow switchgrass on marginal land with minimal irrigation is considered an important advantage for this crop, responses of switchgrass to water limitation have received little attention. Here we describe switchgrass responses during drought stress and recovery at multiple levels of biological organization. A controlled drought treatment was applied by withholding water to reduce volumetric water content (VWC) of growth media from ~45% to ~3% over a period of 14 days, and recovery from drought was evaluated by re-watering to 16% VWC within 4 hours. Gas exchange and photosynthetic traits were substantially reduced in the drought treatment, and several traits (qP, iWUE, Fs, Fm) recovered rapidly following re-watering. Correspondingly large effects were evident in gene expression profiles, with 37% of transcripts differentially expressed in the drought treatment. Interestingly, many transcripts (2,365) showed opposite responses to drought depending on time of day. Rapid transcriptional responses were also observed during recovery. Metabolite profiling revealed enrichment of amino acids, monosaccharides, and C4 photosynthetic intermediates during drought. Most transcripts associated with C4 photosynthesis were down-regulated in drought, while carbonic anhydrase and certain malic enzyme isoforms were up-regulated. Expression of certain genes was closely correlated with physiology or metabolite abundance, and many showed strongly non-linear relationships that highlight physiological or metabolic thresholds. These findings identify genes and processes involved in short-term drought stress responses of switchgrass, and refine the questions to be addressed in future studies of genetic variation in water use efficiency of this and other C4 grasses.