Abstract
Alfalfa (Medicago sativa L.) has a high potential for sustainable bioethanol production, particularly because of its low reliance on N fertilizer. We assessed near-infrared reflectance spectroscopy (NIRS) as a high-throughput technique to measure cell wall (CW) degradability in a large number of lignified alfalfa stem samples. We also used a powerful immunological approach, glycome profiling, and chemical analyses to increase our knowledge of the composition of CW polysaccharides of alfalfa stems with various levels of degradability. NIRS accurately predicted CW degradability in four different alfalfa cultivars, as assessed by glucose released following enzymatic saccharification (R 2 = 0. 94). There was a large genetic diversity for enzyme-released glucose. The 10 genotypes with the highest (D+) and 10 genotypes with the lowest (D-) amounts of enzyme-released glucose of a biomass-type (Orca) and a winterhardy-type (54V54) cultivar were further characterized. Glycome profiling showed that there were very few differences in CW polysaccharide composition between the two groups, although the D+ genotypes were at least 35 % more degradable than the D- genotypes. Determination of CW composition by chemical analyses showed that a higher lignin content of the D- genotypes was closely related to their lower enzyme-released glucose (R = -0. 83). In each cultivar tested, 20 D+ genotypes and 20 D- genotypes were intercrossed to generate D+ and D- populations. Assessment of CW enzyme-released glucose in the progenies showed that this trait is genetically inherited. The large genetic diversity for enzyme-released glucose and its potential for selection support the huge potential of alfalfa for the sustainable production of bio-ethanol.
| Original language | English |
|---|---|
| Pages (from-to) | 904-914 |
| Number of pages | 11 |
| Journal | Bioenergy Research |
| Volume | 5 |
| Issue number | 4 |
| DOIs | |
| State | Published - Dec 2012 |
| Externally published | Yes |
Funding
Acknowledgments The authors sincerely thank Mrs. Josée Bourassa for her technical assistance and Monique Arts for proof-reading the article. This work was supported by the Cellulosic Biofuel Network of the Agricultural Bioproducts Innovation Program of Agriculture and Agri-Food Canada. The glycome profiling was supported by the Bio-Energy Science Center administerd by Oak Ridge National Laboratory and funded by a grant (DE-AC05-00OR22725) from the Office of Biological and Environmental Research, Office of Science, United States, Department of Energy. The generation of the CCRC series of cell wall glycan-directed monoclonal antibodies used in this work was supported by the United States National Science Foundation Plant Genome Program (DBI-0421683).
| Funders | Funder number |
|---|---|
| Agricultural Bioproducts Innovation Program of Agriculture and Agri-Food Canada | |
| National Science Foundation | DBI-0421683 |
| Office of Science | |
| Biological and Environmental Research | |
| Oak Ridge National Laboratory | DE-AC05-00OR22725 |
Keywords
- Alfalfa
- Cell wall degradability
- Enzyme-released glucose
- Glycome profiling
- Near-infrared spectroscopy
- Selection
