Fumarate-directed quick breeding of low-methane rice for the global environment

Paddy rice is one of the largest anthropogenic sources for atmospheric methane and its greenhouse effect is equivalent to CO2 emissions from ca 250 million cars. Thus, there is an urgent need to reduce methane fluxes from paddies for the global environment.

In a previous Formas project, we have published the world´s first low-methane rice, SUSIBA2 rice (Su et al 2015, Nature 523, 602-606). SUSIBA2 rice produced 50% more grains with over 90% reduced methane emissions. We have found that fumarate is a key player between SUSIBA2 rice and methanogens for methane emissions.

During rice cultivation, SUSIBA2 rice started to reduce methane emissions from week 6 after planting by, 1) secreting less fumarate for microbial growth, 2) changing root size to smaller leading to less physical area for habitat of methanogens, However, SUSIBA2 rice is genetically modified rice.

In this proposal we suggest to continue the research by, 1) using fumarate as a chemical probe, and fumarate related genes and the SUSIBA or yin-yang gene as gene probes in screening and yin-yang Marker Assisted crossbreeding for low-methane rice (this point is the project focus), 2) finding how fumarate stimulates propagation of methanogens, 3) using DNA free CRISPR/Cas to edit the SUSIBA gene for less fumarate secretion to understand the breeding mechanism.

We aim at achieving low-methane rice quickly for global production in collaboration with different stakeholders e.g. Lantmännen to mitigate climate change.