ARS | Publication request: SALMON SILK GENES CONTRIBUTE TO THE ELUCIDATION OF THE FLAVONE PATHWAY IN MAIZE (ZEA MAYS L.)

Submitted to: Journal of Heredity
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 11, 2004
Publication Date: May 1, 2004
Citation: Mcmullen, M.D., Kross, H., Snook, M.E., Cortes-Cruz, M., Houchins, K.E., Musket, T.A., Coe Jr, E.H. 2004. Salmon silk genes contribute to the elucidation of the flavone pathway in maize (zea mays l.). Journal of Heredity. 95(3):225-233.

Interpretive Summary: A chemical compound found in corn silks known as maysin has anti-insect activity, particularly against the corn earworm. The corn earworm is a major insect pest of corn throughout the Americas. In this study, we showed that corn plants that have salmon colored silks carry mutations in the biochemical pathway to maysin. We used these mutations to define the biochemical steps in the synthesis of maysin. These results are important to scientists studying the synthesis of anti-insect compounds and the biochemistry of plant secondary products. These studies also define the biological basis of a corn phenotype that has been known since the 1920's.

Technical Abstract: We utilized maize (Zea mays L.) lines expressing the salmon silk (sm) phenotype, quantitative trait locus analysis, and analytical chemistry of flavone compounds to establish the order of undefined steps in the synthesis of the flavone maysin in maize silks. In addition to the previously described sm1 gene, we identified a second sm locus, which we designate sm2, located on the long arm of maize chromosome 2. Our data indicate that the sm1 gene encodes or controls a glucose modification enzyme and sm2 encodes or controls a rhamnosyl transferase. The order of intermediates in the late steps of maysin synthesis was established as luteolin > isoorientin > rhamnosylisoorientin > maysin.