Seasonal below‐ground metabolism in switchgrass

Journal Article · Mon Nov 27 00:00:00 EST 2017 · The Plant Journal

DOI:https://doi.org/10.1111/tpj.13742· OSTI ID:1410369

Palmer, Nathan A. ^[1]; Saathoff, Aaron J. ^[1]; Scully, Erin D. ^[2]; Tobias, Christian M. ^[3]; Twigg, Paul ^[4]; Madhavan, Soundararajan ^[5]; Schmer, Marty ^[6]; Cahoon, Rebecca ^[5]; Sattler, Scott E. ^[1]; Edmé, Serge J. ^[1]; Mitchell, Robert B. ^[1]; Sarath, Gautam ^[1]

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1. Wheat, Sorghum, and Forage Research Unit USDA‐ARS Lincoln NE 68583 USA, Department of Agronomy and Horticulture University of Nebraska at Lincoln Lincoln NE 68583 USA
2. Stored Product Insect and Engineering Research Unit USDA‐Agricultural Research Service Center for Grain and Animal Health Manhattan KS 66502 USA
3. Crop Improvement and Genetics Research USDA‐ARS Albany CA 94710 USA
4. Biology Department University of Nebraska at Kearney Kearney NE 68849 USA
5. Department of Biochemistry University of Nebraska at Lincoln Lincoln NE 68588 USA
6. Agroecosystem Management Research Unit USDA‐ARS Lincoln NE 68583 USA, Department of Agronomy and Horticulture University of Nebraska at Lincoln Lincoln NE 68583 USA

Summary Switchgrass ( Panicum virgatum ), a perennial, polyploid, C4 warm‐season grass is among the foremost herbaceous species being advanced as a source of biomass for biofuel end uses. At the end of every growing season, the aerial tissues senesce, and the below‐ground rhizomes become dormant. Future growth is dependent on the successful over‐wintering of the rhizomes. Although the importance of rhizome health to overall year‐upon‐year plant productivity has been long recognized, there is limited information on seasonal changes occurring during dormancy at both the transcriptome and metabolite levels. Here, global changes in transcriptomes and metabolites were investigated over two growing seasons in rhizomes harvested from field‐grown plants. The objectives were: (a) synthesize information on cellular processes that lead to dormancy; and (b) provide models that could account for major metabolic pathways present in dormant switchgrass rhizomes. Overall, metabolism during dormancy appeared to involve discrete but interrelated events. One was a response to abscisic acid that resulted in dehydration, increases in osmolytes and upregulation of autophagic processes, likely through the target of rapamycin complex and sucrose non‐fermentative‐related kinase‐based signaling cascades. Another was a recalibration of energy transduction through apparent reductions in mitochondrial oxidative phosphorylation, increases in substrate level generation of ATP and reducing equivalents, and recycling of N and possibly CO ₂ through refixation. Lastly, transcript abundances indicated that cold‐related signaling was also occurring. Altogether, these data provide a detailed overview of rhizome metabolism, especially during dormancy, which can be exploited in the future to improve winter survival in switchgrass.

• Sponsoring Organization: USDOE
• Grant/Contract Number: DE‐AI02‐09ER64829
• OSTI ID: 1410369
• Journal Information: The Plant Journal, Journal Name: The Plant Journal Vol. 92 Journal Issue: 6; ISSN 0960-7412
• Publisher: Wiley-Blackwell
• Country of Publication: United Kingdom
• Language: English