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De novo domestication of Oryza longistaminata
De novo domestication of Oryza longistaminata
As climate change intensifies, the development of climate-resilient rice which can tolerate abiotic stresses is urgently needed. Wild relatives of rice, such as Oryza longistaminata, may have abundant and virtually untapped genetic diversity and can thus be an essential source of germplasm for the improvement of abiotic stress tolerance in cultivated rice.
Unfortunately, the barriers of traditional breeding approaches, such as backcrossing and transgenesis, make it challenging and complex to transfer the underlying resilience traits between plants, especially if these traits are located on multiple chromosomes.
De novo domestication via genome editing is a quick approach to producing rice with high yields from orphans or wild relatives. African wild rice, Oryza longistaminata, which is part of the AA-genome Oryza species has two types of propagation strategies viz. vegetative propagation via rhizome and seed propagation. It also shows remarkable tolerance to multiple types of abiotic stress, making it a key candidate for heat, drought, and salinity tolerance, and it is also resistant to lodging.
Oryza longistaminata is also perennial and it propagates via rhizomes both of which are traits that are highly valuable for the sustainable production of rice as it dramatically reduces the need for fertilizer. Therefore, Oryza longistaminata may be a good candidate for de novo domestication through genome editing to obtain rice that is more climate resilient than modern elite cultivars of Oryza sativa.
Possible timeline for de novo domestication of Oryza longistaminata
- first, establishment of a targeted transformation system and selection of key genotype(s) based on field performance under the relevant abiotic stress conditions. Moreover, the key genotype(s) must not suffer from self-incompatibility, which is a common issue in this species;
- multiple cycles of knockout of target genes related to e.g., “non-shattering”, awnlessness”, “seed quality”, “root architecture” and “nutrient uptake” and;
- a final cycle of field evaluation in the relevant target environments.