There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.
Atmospheric methane is the second most important greenhouse gas after carbon dioxide,
and is responsible for about 20% of the global warming effect since pre-industrial
times. Rice paddies are the largest anthropogenic methane source and produce 7-17%
of atmospheric methane. Warm waterlogged soil and exuded nutrients from rice roots
provide ideal conditions for methanogenesis in paddies with annual methane emissions
of 25-100-million tonnes. This scenario will be exacerbated by an expansion in rice
cultivation needed to meet the escalating demand for food in the coming decades. There
is an urgent need to establish sustainable technologies for increasing rice production
while reducing methane fluxes from rice paddies. However, ongoing efforts for methane
mitigation in rice paddies are mainly based on farming practices and measures that
are difficult to implement. Despite proposed strategies to increase rice productivity
and reduce methane emissions, no high-starch low-methane-emission rice has been developed.
Here we show that the addition of a single transcription factor gene, barley SUSIBA2
(refs 7, 8), conferred a shift of carbon flux to SUSIBA2 rice, favouring the allocation
of photosynthates to aboveground biomass over allocation to roots. The altered allocation
resulted in an increased biomass and starch content in the seeds and stems, and suppressed
methanogenesis, possibly through a reduction in root exudates. Three-year field trials
in China demonstrated that the cultivation of SUSIBA2 rice was associated with a significant
reduction in methane emissions and a decrease in rhizospheric methanogen levels. SUSIBA2
rice offers a sustainable means of providing increased starch content for food production
while reducing greenhouse gas emissions from rice cultivation. Approaches to increase
rice productivity and reduce methane emissions as seen in SUSIBA2 rice may be particularly
beneficial in a future climate with rising temperatures resulting in increased methane
emissions from paddies.
1] Institute of Biotechnology, Fujian Academy of Agricultural Sciences, Fuzhou 350003,
China  Department of Plant Biology, Uppsala BioCenter, Linnean Center for Plant
Biology, Swedish University of Agricultural Sciences, PO Box 7080, SE-75007 Uppsala,
Department of Plant Biology, Uppsala BioCenter, Linnean Center for Plant Biology,
Swedish University of Agricultural Sciences, PO Box 7080, SE-75007 Uppsala, Sweden.
1] Department of Plant Biology, Uppsala BioCenter, Linnean Center for Plant Biology,
Swedish University of Agricultural Sciences, PO Box 7080, SE-75007 Uppsala, Sweden
 Hunan Provincial Key Laboratory of Crop Germplasm Innovation and Utilization,
Hunan Agricultural University, Changsha 410128, China.
Institute of Biotechnology, Fujian Academy of Agricultural Sciences, Fuzhou 350003,
The Environmental Molecular Sciences Laboratory (EMSL), Pacific Northwest National
Laboratory, PO Box 999, K8-93 Richland, Washington 99352, USA.
Department of Microbiology, Uppsala BioCenter, Swedish University of Agricultural
Sciences, SE-75007 Uppsala, Sweden.