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Sun X, Cheng L, Jonker A, Munidasa S, Pacheco D. A Review: Plant Carbohydrate Types—The Potential Impact on Ruminant Methane Emissions. Front Vet Sci 2022; 9:880115. [PMID: 35782553 PMCID: PMC9249355 DOI: 10.3389/fvets.2022.880115] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 05/16/2022] [Indexed: 11/25/2022] Open
Abstract
Carbohydrates are the major component of most ruminant feeds. The digestion of carbohydrates in the rumen provides energy to the ruminants but also contributes to enteric methane (CH4) emissions. Fresh forage is the main feed for grazing ruminants in temperate regions. Therefore, this review explored how dietary carbohydrate type and digestion affect ruminant CH4 emissions, with a focus on fresh forage grown in temperate regions. Carbohydrates include monosaccharides, disaccharides, oligosaccharides, and polysaccharides. Rhamnose is the only monosaccharide that results in low CH4 emissions. However, rhamnose is a minor component in most plants. Among polysaccharides, pectic polysaccharides lead to greater CH4 production due to the conversion of methyl groups to methanol and finally to CH4. Thus, the degree of methyl esterification of pectic polysaccharides is an important structural characteristic to better understand CH4 emissions. Apart from pectic polysaccharides, the chemical structure of other polysaccharides per se does not seem to affect CH4 formation. However, rumen physiological parameters and fermentation types resulting from digestion in the rumen of polysaccharides differing in the rate and extent of degradation do affect CH4 emissions. For example, low rumen pH resulting from the rapid degradation of readily fermentable carbohydrates decreases and inhibits the activities of methanogens and further reduces CH4 emissions. When a large quantity of starch is supplemented or the rate of starch degradation is low, some starch may escape from the rumen and the escaped starch will not yield CH4. Similar bypass from rumen digestion applies to other polysaccharides and needs to be quantified to facilitate the interpretation of animal experiments in which CH4 emissions are measured. Rumen bypass carbohydrates may occur in ruminants fed fresh forage, especially when the passage rate is high, which could be a result of high feed intake or high water intake. The type of carbohydrates affects the concentration of dissolved hydrogen, which consequently alters fermentation pathways and finally results in differences in CH4 emissions. We recommend that the degree of methyl esterification of pectic polysaccharides is needed for pectin-rich forage. The fermentation type of carbohydrates and rumen bypass carbohydrates should be determined in the assessment of mitigation potential.
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Affiliation(s)
- Xuezhao Sun
- The Innovation Centre of Ruminant Precision Nutrition and Smart and Ecological Farming, Jilin Agricultural Science and Technology University, Jilin, China
- Jilin Inter-Regional Cooperation Centre for the Scientific and Technological Innovation of Ruminant Precision Nutrition and Smart and Ecological Farming, Jilin, China
- Grasslands Research Centre, AgResearch Limited, Palmerston North, New Zealand
- *Correspondence: Xuezhao Sun
| | - Long Cheng
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Melbourne, VIC, Australia
| | - Arjan Jonker
- Grasslands Research Centre, AgResearch Limited, Palmerston North, New Zealand
| | - Sineka Munidasa
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Melbourne, VIC, Australia
| | - David Pacheco
- Grasslands Research Centre, AgResearch Limited, Palmerston North, New Zealand
- David Pacheco
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Beck RH. Statistic thermodynamic analysis of fructans – Part 4: Modeling inulin biosynthesis as a non-equilibium thermodynamic process. SUGAR INDUSTRY 2017. [DOI: 10.36961/si18245] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A model for the mathematical description of inulin biosynthesis with particular focus on the dynamics of the sucrose and 1-kestose concentration has been developed. The model takes into account the specific action of the two involved enzymes SST and FFT. In principle, inulin biosynthesis can thus be described as a thermodynamically stabilizing process leading into a stable nodal sink over time. In the initial phases of the reaction, oscillation of sucrose and 1-kestose concentration is observed, dampening rapidly for both products into a stable steady state condition. Applying the same boundary conditions, a higher number average degree of polymerization will lead to a higher frequency and amplitude in oscillation.
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Gallagher JA, Cairns AJ, Thomas D, Timms-Taravella E, Skøt K, Charlton A, Williams P, Turner LB. Fructan synthesis, accumulation and polymer traits. II. Fructan pools in populations of perennial ryegrass (Lolium perenne L.) with variation for water-soluble carbohydrate and candidate genes were not correlated with biosynthetic activity and demonstrated constraints to polymer chain extension. FRONTIERS IN PLANT SCIENCE 2015; 6:864. [PMID: 26528321 PMCID: PMC4606054 DOI: 10.3389/fpls.2015.00864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 09/30/2015] [Indexed: 06/05/2023]
Abstract
Differences have been shown between ryegrass and fescue within the Festulolium subline introgression family for fructan synthesis, metabolism, and polymer-size traits. It is well-established that there is considerable variation for water-soluble carbohydrate and fructan content within perennial ryegrass. However there is much still to be discovered about the fructan polymer pool in this species, especially in regard to its composition and regulation. It is postulated that similar considerable variation for polymer traits may exist, providing useful polymers for biorefining applications. Seasonal effects on fructan content together with fructan synthesis and polymer-size traits have been examined in diverse perennial ryegrass material comprising contrasting plants from a perennial ryegrass F2 mapping family and from populations produced by three rounds of phenotypic selection. Relationships with copy number variation in candidate genes have been investigated. There was little evidence of any variation in fructan metabolism across this diverse germplasm under these conditions that resulted in substantial differences in the complement of fructan polymers present in leaf tissue at high water-soluble carbohydrate concentrations. The importance of fructan synthesis during fructan accumulation was unclear as fructan content and polymer characteristics in intact plants during the growing season did not reflect the capacity for de novo synthesis. However, the retention of fructan in environmental conditions favoring high sink/low source demand may be an important component of the high sugar trait and the roles of breakdown and turnover are discussed.
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Affiliation(s)
- Joe A. Gallagher
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth UniversityGogerddan, Aberystwyth, UK
| | - Andrew J. Cairns
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth UniversityGogerddan, Aberystwyth, UK
| | - David Thomas
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth UniversityGogerddan, Aberystwyth, UK
| | - Emma Timms-Taravella
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth UniversityGogerddan, Aberystwyth, UK
| | - Kirsten Skøt
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth UniversityGogerddan, Aberystwyth, UK
| | - Adam Charlton
- The Biocomposites Centre, Bangor UniversityBangor, UK
| | | | - Lesley B. Turner
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth UniversityGogerddan, Aberystwyth, UK
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He X, Chen Z, Wang J, Li W, Zhao J, Wu J, Wang Z, Chen X. A sucrose:fructan-6-fructosyltransferase (6-SFT) gene from Psathyrostachys huashanica confers abiotic stress tolerance in tobacco. Gene 2015; 570:239-47. [PMID: 26072162 DOI: 10.1016/j.gene.2015.06.023] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 06/06/2015] [Accepted: 06/08/2015] [Indexed: 10/23/2022]
Abstract
Fructans are accessible carbohydrate reserves in various plant species, which possess many physiological functions including anti-oxidation, stabilizing subcellular structures, and osmotic adjustment. In addition, fructans may play important roles in stress tolerance in plant species. In this study, we isolated a Psathyrostachys huashanica (2n=2x=14, NsNs) sucrose:fructan-6-fructosyltransferase (Ph-6-SFT) using homologous cloning and genomic walking. Sequencing and gene structure analysis showed that Ph-6-SFT contains four exons and three introns, with a transcript of 2207 bp. Sequence analysis indicated that the coding sequence of Ph-6-SFT is 1851 bp long and it encodes 616 amino acids, where the structure shares high similarity with 6-SFTs from other plants. Furthermore, Ph-6-SFT was transferred into tobacco (Nicotiana tabacum L.) cv. W38 via Agrobacterium-mediated transformation. Compared with the wild-type plants, the transgenic tobacco plants exhibited a much higher tolerance of drought, cold, and high salinity. In all conditions, physiological studies showed that the tolerance of transgenic plants was associated with the accumulation of carbohydrate and proline, but reductions in malondialdehyde. Our results suggest that the 6-SFT gene from P. huashanica enhanced stress tolerance in tobacco plants and it may be applied as a genetic tool for improving stress tolerance in other crops.
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Affiliation(s)
- Xiaolan He
- College of Agronomy, Northwest A&F University, Yangling 712100, Shaanxi, China; Shaanxi Key Laboratory of Genetic Engineering for Plant Breeding, China
| | - Zhenzhen Chen
- College of Agronomy, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Jianwei Wang
- College of Environment and Life Science, Kaili University, Kaili 556011, GuiZhou, China
| | - Wenxu Li
- Institute for Wheat Research, Henan Academy of Agricultural Sciences, Zhengzhou 450002, Henan, China
| | - Jixin Zhao
- College of Agronomy, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Jun Wu
- College of Agronomy, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Zhonghua Wang
- College of Agronomy, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Xinhong Chen
- College of Agronomy, Northwest A&F University, Yangling 712100, Shaanxi, China; Shaanxi Key Laboratory of Genetic Engineering for Plant Breeding, China.
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Abeynayake SW, Etzerodt TP, Jonavičienė K, Byrne S, Asp T, Boelt B. Fructan metabolism and changes in fructan composition during cold acclimation in perennial ryegrass. FRONTIERS IN PLANT SCIENCE 2015; 6:329. [PMID: 26029229 PMCID: PMC4428078 DOI: 10.3389/fpls.2015.00329] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 04/27/2015] [Indexed: 05/20/2023]
Abstract
Perennial ryegrass (Lolium perenne L.) produces high levels of fructans as a mixture of oligosaccharides and polysaccharides with different degrees of polymerization (DP). The present study describes the analysis of the compositional changes in the full spectrum of fructans, fructan distribution between above ground biomass (top) and the roots, and the transcription of candidate genes involved in fructan metabolism during cold acclimation in perennial ryegrass variety "Veyo" and ecotype "Falster" from distinct geographical origins. We observed changes in fructan composition and induction of low-DP fructans, especially DP = 4, in both the top and the roots of "Veyo" and "Falster" in response to low-temperature stress. The accumulation of DP > 50 fructans was only apparent in the top tissues where the Lp1-FFT expression is higher compared to the roots in both "Veyo" and "Falster." Our results also show the accumulation and depolymerization of fructans with different DP, together with the induction of genes encoding fructosyltransferases and fructan exohydrolases in both "Veyo" and "Falster" during cold acclimation, supporting the hypothesis that fructan synthesis and depolymerization occurring simultaneously. The ecotype "Falster," adapted to cold climates, increased total fructan content and produced more DP > 7 fructans in the roots than the variety "Veyo," adapted to warmer climates. This indicates that high-DP fructan accumulation in roots may be an adaptive trait for plant recovery after abiotic stresses.
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Affiliation(s)
- Shamila W. Abeynayake
- Department of Agroecology, Aarhus UniversitySlagelse, Denmark
- Department of Molecular Biology and Genetics, Aarhus UniversitySlagelse, Denmark
| | | | - Kristina Jonavičienė
- Laboratory of Genetics and Physiology, Institute of Agriculture, Lithuanian Research Centre for Agriculture and ForestryAkademija, Lithuania
| | - Stephen Byrne
- Department of Molecular Biology and Genetics, Aarhus UniversitySlagelse, Denmark
| | - Torben Asp
- Department of Molecular Biology and Genetics, Aarhus UniversitySlagelse, Denmark
| | - Birte Boelt
- Department of Agroecology, Aarhus UniversitySlagelse, Denmark
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Barrett BA, Faville MJ, Nichols SN, Simpson WR, Bryan GT, Conner AJ. Breaking through the feed barrier: options for improving forage genetics. ANIMAL PRODUCTION SCIENCE 2015. [DOI: 10.1071/an14833] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Pasture based on perennial ryegrass (Lolium perenne L.) and white clover (Trifolium repens L.) is the foundation for production and profit in the Australasian pastoral sectors. The improvement of these species offers direct opportunities to enhance sector performance, provided there is good alignment with industry priorities as quantified by means such as the forage value index. However, the rate of forage genetic improvement must increase to sustain industry competitiveness. New forage technologies and breeding strategies that can complement and enhance traditional approaches are required to achieve this. We highlight current and future research in plant breeding, including genomic and gene technology approaches to improve rate of genetic gain. Genomic diversity is the basis of breeding and improvement. Recent advances in the range and focus of introgression from wild Trifolium species have created additional specific options to improve production and resource-use-efficiency traits. Symbiont genetic resources, especially advances in grass fungal endophytes, make a critical contribution to forage, supporting pastoral productivity, with benefits to both pastures and animals in some dairy regions. Genomic selection, now widely used in animal breeding, offers an opportunity to lift the rate of genetic gain in forages as well. Accuracy and relevance of trait data are paramount, it is essential that genomic breeding approaches be linked with robust field evaluation strategies including advanced phenotyping technologies. This requires excellent data management and integration with decision-support systems to deliver improved effectiveness from forage breeding. Novel traits being developed through genetic modification include increased energy content and potential increased biomass in ryegrass, and expression of condensed tannins in forage legumes. These examples from the wider set of research emphasise forage adaptation, yield and energy content, while covering the spectrum from exotic germplasm and symbionts through to advanced breeding strategies and gene technologies. To ensure that these opportunities are realised on farm, continuity of industry-relevant delivery of forage-improvement research is essential, as is sustained research input from the supporting pasture and plant sciences.
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Rasmussen S, Parsons AJ, Xue H, Liu Q, Jones CS, Ryan GD, Newman JA. Transcript profiling of fructan biosynthetic pathway genes reveals association of a specific fructosyltransferase isoform with the high sugar trait in Lolium perenne. JOURNAL OF PLANT PHYSIOLOGY 2014; 171:475-85. [PMID: 24655383 DOI: 10.1016/j.jplph.2013.12.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Revised: 12/12/2013] [Accepted: 12/12/2013] [Indexed: 05/18/2023]
Abstract
Lolium perenne cultivars with elevated levels of fructans in leaf blades (high sugar-content grasses) have been developed to improve animal nutrition and reduce adverse environmental impacts of pastoral agricultural systems. Expression of the high sugar trait can vary substantially depending on genotype×environment (G×E) interactions. We grew three potential high sugar-content and a control cultivar in three temperature regimes and quantified water soluble carbohydrates (WSCs) and the expression of all functionally characterised L. perenne fructan pathway genes in leaf tissues. We also analysed the distribution, expression and sequence variation of two specific isoforms of Lp6G-FFT (fructan: fructan 6G-fructosyltransferase). Our study confirmed a significant G×E interaction affecting the accumulation of fructans in the high sugar-content cultivar AberDart, which accumulated higher levels of high DP (degree of polymerisation) fructans in blades compared to the control cultivar only when grown at 20°C (day)/10°C (night) temperatures. The cultivar Expo on the other hand accumulated significantly higher levels of high DP fructans in blades independent of temperature. Fructan levels in pseudostems were higher than in blades, and they increased markedly with decreasing temperature, but there was no consistent effect of cultivar in this tissue. The expression of the high sugar trait was generally positively correlated with transcript levels of fructosyltransferases. Presence and expression of only one of the two known 6G-FFT isoforms was positively correlated with high fructan biosynthesis, while the second isoform was associated with low fructan concentrations and positively correlated with fructan exohydrolase gene expression. The presence of distinct 6G-FFT sequence variants appears to be associated with the capacity of high sugar-content grasses to accumulate higher fructan levels particularly at warmer temperatures. These findings might be exploited for the selection and breeding of 'warm-effective' high sugar-content grasses to overcome some of the limitations of current high sugar-content ryegrass cultivars.
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Affiliation(s)
- Susanne Rasmussen
- AgResearch Grasslands Research Centre, P.B. 11008, Palmerston North, New Zealand.
| | - Anthony J Parsons
- Institute of Agriculture and Environment, Massey University, P.B. 11222, Palmerston North, New Zealand
| | - Hong Xue
- AgResearch Grasslands Research Centre, P.B. 11008, Palmerston North, New Zealand
| | - Qianhe Liu
- AgResearch Grasslands Research Centre, P.B. 11008, Palmerston North, New Zealand
| | - Christopher S Jones
- AgResearch Grasslands Research Centre, P.B. 11008, Palmerston North, New Zealand
| | - Geraldine D Ryan
- School of Environmental Sciences, University of Guelph, Ontario, Canada N1G 2W1
| | - Jonathan A Newman
- School of Environmental Sciences, University of Guelph, Ontario, Canada N1G 2W1
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