Constit. of Oryza sativa (rice)
Momilactone B is an allelopathic agent produced from the roots of rice (Oryza sativa L.) (100 mg from 200 kg dry rice husk). It has been shown to be produced in high concentrations by the roots of rice seedlings. The production of momilactone B has also been induced in response to infection by blast fungus (Pyricularia oryzae) or irradiated with UV light. More recently is has been shown to be a potential chemotherapeutic agent against human colon cancer.; The second step is the cyclization of syn-CDP to 9?-pimara-7,15-diene. This step is initiated by the elimination of the diphosphate group, a type A cyclization. The genes encoding for the type A cyclase were found by Otomo et al.. in 2004. It is suggested that OsKS4, located on chromosome 4 (14.3cM) is one of the genes responsible for phytoalexin biosynthesis. After UV-radiation, OsKS4 mRNA levels rise drastically in response to the attack.
|