Divergent Metabolic Changes in Rhizomes of Lowland and Upland Switchgrass (Panicum virgatum) from Early Season through Dormancy Onset

Authors

Nathan A. Palmer, University of Nebraska–LincolnFollow
Gautam Sarath, University of Nebraska - LincolnFollow
Michael J. Bowman, USDA, Agricultural Research Service
Aaron J. Saathoff, University of Nebraska-Lincoln
Serge J. Edmé, University of Nebraska-LincolnFollow
Robert B. Mitchell, University of Nebraska - LincolnFollow
Christian M. Tobias, USDA
Soundararajan Madhavan, University of Nebraska-Lincoln
Erin D. Scully, USDA, Agricultural Research Service
Scott E. Sattler, University of Nebraska - LincolnFollow

Date of this Version

4-21-2023

Citation

Palmer, N.A.; Sarath, G.; Bowman, M.J.; Saathoff, A.J.; Edmé, S.J.; Mitchell, R.B.; Tobias, C.M.; Madhavan, S.; Scully, E.D.; Sattler, S.E. Divergent Metabolic Changes in Rhizomes of Lowland and Upland Switchgrass (Panicum virgatum) from Early Season through Dormancy Onset. Plants 2023, 12, 1732. https://doi.org/10.3390/ plants12081732

Comments

Open access.

Abstract

High-biomass-yielding southerly adapted switchgrasses (Panicum virgatum L.) frequently suffer from unpredictable winter hardiness at more northerly sites arising from damage to rhizomes that prevent effective spring regrowth. Previously, changes occurring over the growing season in rhizomes sampled from a cold-adapted tetraploid upland cultivar, Summer, demonstrated a role for abscisic acid (ABA), starch accumulation, and transcriptional reprogramming as drivers of dormancy onset and potential keys to rhizome health during winter dormancy. Here, rhizome metabolism of a high-yielding southerly adapted tetraploid switchgrass cultivar, Kanlow—which is a significant source of genetics for yield improvement—was studied over a growing season at a northern site. Metabolite levels and transcript abundances were combined to develop physiological profiles accompanying greening through the onset of dormancy in Kanlow rhizomes. Next, comparisons of the data to rhizome metabolism occurring in the adapted upland cultivar Summer were performed. These data revealed both similarities as well as numerous differences in rhizome metabolism that were indicative of physiological adaptations unique to each cultivar. Similarities included elevated ABA levels and accumulation of starch in rhizomes during dormancy onset. Notable differences were observed in the accumulation of specific metabolites, the expression of genes encoding transcription factors, and several enzymes linked to primary metabolism.