title: Global changes in mineral transporters in tetraploid switchgrasses (Panicum virgatum L.).
abstract: Switchgrass (Panicum virgatum L) is perennial, C4 grass with great potential as a biofuel crop. An in-depth understanding of the mechanisms that control mineral uptake, distribution and remobilization will benefit sustainable production. Nutrients are mobilized from aerial portions to below-ground crowns and rhizomes as a natural accompaniment to above-ground senescence post seed-set. Mineral uptake and remobilization is dependent on transporters, however, little if any information is available about the specific transporters that are needed and how their relative expression changes over a growing season. Using well-defined classes of mineral transporters, we identified 520 genes belonging to 40 different transporter classes in the tetraploid switchgrass genome. Expression patterns were determined for many of these genes using publically available transcriptomic datasets obtained from both greenhouse and field grown plants. Certain transporters showed strong temporal patterns of expression in distinct developmental stages of the plant. Gene-expression was verified for selected transporters using qRT-PCR. By and large these analyses confirmed the developmental stage-specific expression of these genes. Mineral analyses indicated that K, Fe, Mg, Co, and As had a similar pattern of accumulation with apparent limited remobilization at the end of the growing season. These initial analyses will serve as a foundation for more detailed examination of the nutrient biology of switchgrass.
authors.affiliation: USDA-Agricultural Research Service, Grain, Forage, and Bioenergy Research Unit Lincoln, NE, USA ; Department of Agronomy and Horticulture, University of Nebraska Lincoln, NE, USA.
authors.forename: Nathan A
authors.initials: NA
authors.lastname: Palmer
authors.affiliation: USDA-Agricultural Research Service, Grain, Forage, and Bioenergy Research Unit Lincoln, NE, USA ; LI-COR Biosciences Lincoln, NE, USA.
authors.forename: Aaron J
authors.initials: AJ
authors.lastname: Saathoff
authors.affiliation: Department of Agronomy and Horticulture, University of Nebraska Lincoln, NE, USA.
authors.forename: Brian M
authors.initials: BM
authors.lastname: Waters
authors.affiliation: Department of Entomology, University of Nebraska Lincoln, NE, USA.
authors.forename: Teresa
authors.initials: T
authors.lastname: Donze
authors.affiliation: Department of Entomology, University of Nebraska Lincoln, NE, USA.
authors.forename: Tiffany M
authors.initials: TM
authors.lastname: Heng-Moss
authors.affiliation: Biology Department, University of Nebraska Kearney, NE, USA.
authors.forename: Paul
authors.initials: P
authors.lastname: Twigg
authors.affiliation: USDA-Agricultural Research Service, Genomics and Gene Discovery Research Unit, Western Regional Research Center Albany, CA, USA.
authors.forename: Christian M
authors.initials: CM
authors.lastname: Tobias
authors.affiliation: USDA-Agricultural Research Service, Grain, Forage, and Bioenergy Research Unit Lincoln, NE, USA.
authors.forename: Gautam
authors.initials: G
authors.lastname: Sarath
keywords: Panicum virgatum; bioenergy; crowns and rhizomes; growing-season; mineral transporters; nutrients; qPCR; switchgrass