Research Organisms

Red Rice (Oryza longistaminata A. Chev & Röhr

Red rice (Oryza longistaminata A. Chev & Röhr), also known as longstamen or wild African rice, is a close relative of the cultivated Asian rice (Oryza sativa). Together with other cereals such as wheat and rye, it belongs to the Poaceae family. It is a tall (over 2 m) perennial grass with several distinct morphological features facilitating its identification, such as a very long, pointed ligule. Its natural habitat is tropical Africa, and it is considered a noxious weed in the United States. Red rice grows best in swampy and sunny areas. Because of its partial self-incompatibility, the seed yields from this species are low, and red rice grain is not commonly marketed.

While not being a major crop, red rice has become a model species since it possesses several traits that are desirable in staple crops. One of these features is its resistance to bacterial blight (caused by Xanthomonas oryzae pv. oryzae). The responsible gene, Xa21, encoding a receptor-like kinase was isolated and integrated into the genome of cultivated rice, conferring resistance to almost all of the known Xanthomonas strains.

Another attractive trait is the rhizomatousness, the cause of both the perenniality and the invasiveness of red rice. Importantly, of the four rhizomatous species in the genus Oryza, red rice is the only one with the AA type genome, the same as cultivated rice. Elucidation of the genetic origin of the rhizomatous trait might facilitate the generation of a perennial form of cultivated rice that would help to reduce soil erosion, a common problem of regional importance in Southeast Asia.