The NZAGRC methane programme is jointly planned and funded in partnership with the PGgRc and aligns with existing MPI programmes funded through SLMACC and New Zealand funding in support of the Global Research Alliance on agricultural greenhouse gases. It aims to reduce emissions by directly targeting the methane producing methanogens through the discovery of small molecule inhibitors and vaccines and indirectly through feeding and changes in animal phenotype.
- Breeding: Research to understand the genetics of host control of ruminant methane emissions, which aims to develop genetic and genomic selection technologies to reduce methane yield and intensity in sheep. The current stage of the programme involves the development and dissemination of practical tools for selection for lowered emissions. A major part of maximising impact and uptake is to explore relative economic value from increased production and potential increased feed utilisation associated with lowered methane
- Vaccine (jointly supported by PGgRc): A prototype vaccine (which after further development is aimed at producing a vaccine targeted at reducing methane emissions in cattle and sheep by 20%) is being formulated with the help of a commercial partner
- Inhibitors (previously jointly funded but now fully funded by PGgRc): Research to develop cost-effective inhibitors that reduce methane emissions by at least 20% in sheep and cattle—without reducing productivity—is now being developed, with a view to bring the technology to market
- Modelling: A tool to help scientists in the NZAGRC/PGgRc programme to develop hypotheses and predict responses in methane formation is in its final stages
Current progress and research stories
The current objectives within the NZAGRC methane programme have made significant progress this year, with the sheep breeding programme getting closer to delivering breeding values to the national flock.
Comparative genomics of rumen methanogens
Li, Y. (2016). Comparative genomics of rumen methanogens, Massey University. Doctor of Philosophy in Biochemistry: 550.
Methane (CH4) emissions from agriculture represent around 9% of global anthropogenic greenhouse gas emissions. The single largest source of this CH4 is animal enteric fermentation, predominantly from ruminant livestock, where it is produced mainly in their fermentative forestomach (or reticulo-rumen) by a group of archaea known as methanogens. In order to reduce CH4 emissions from ruminants, it is necessary to understand the role of methanogenic archaea in the rumen, and to identify their distinguishing characteristics that can be used to develop CH4 mitigation technologies. To gain insights into the role of methanogens in the rumen environment, two methanogens have been isolated from ovine rumen and their genomes were sequenced: methanogenic archaeon ISO4-H5 of the order Methanomassiliicoccales and Methanobrevibacter sp. D5 of Methanobrevibacter gottschalkii clade. Genomic analysis suggests ISO4-H5 is an obligate hydrogen-dependent methylotrophic methanogen, able to use methanol and methylamines as substrates for methanogenesis. Like other organisms within this order, ISO4-H5 does not possess genes required for the first six steps of hydrogenotrophic methanogenesis. Comparison between the genomes of different members of the order Methanomassiliicoccales revealed strong conservation in energy metabolism, particularly in genes of the methylotrophic methanogenesis pathway, as well as in the biosynthesis and use of pyrrolysine. Unlike members of Methanomassiliicoccales from human sources, ISO4-H5 does not contain the genes required for production of coenzyme M (CoM), and requires external supply of CoM to survive. Methanobrevibacter sp. D5 is a hydrogenotrophic methanogen predicted to utilise CO2 + H2 and formate as substrates. Comparisons between the available Methanobrevibacter genomes has revealed a high conservation in energy metabolism and characteristics specific to each clade. The coexistence of different Methanobrevibacter species in the rumen may be partly due to the physical association Methanobrevibacter species with different microorganisms and host surface, which allow unique niches to be established.
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