Characterization of accumulated compounds in recessive r-r

Earlier studies with single and double recessive mutants of anthocyanin biosynthesis have led to the elucidation of specific roles of the genes in the gene action sequence analysed by Reddy and Coe (1962). From aleurone extracts of r-r one of the isolated compounds gave red color with concentrated H2SO4 as for a chalcone, and pinkish with alcoholic FeCl3 as for presence of a phenolic hydroxyl group. Under the UV light the spot showed yellow fluorescence. The UV data in MeOH, showing lmax 239sh (log E 4.18), 266 (log E 3.99), 319sh (log E 4.20), 379 (log E 4.44), suggested the characteristics of a chalcone. These observations were further confirmed by co-paper chromatography, superimposable UV and IR with an authentic sample of 2', 4', 3,4-tetrahydroxy chalcone (butein). Based on the preliminary data it was concluded that the isolated compound was butein.

Another compound from the same extract gave positive orange color for presence of the flavonoid skeleton with the Shinoda test, and dark coloration with alcoholic FeCl3 for a phenolic hydroxyl group; under the UV light the spot showed yellow fluorescence. The UV data in MeOH, 248 (log E 4.30), 262sh (log E 4.14), 307sh (log E 4.15), 319 (log E 4.24), 362 (log E 4.43), suggested the characteristics of a flavonol. These observations were further confirmed by co-paper chromatography and superimposable UV and IR with an authentic sample of 3,7,3',4' tetra hydroxy flavonol (fisetin). Based on the data it was concluded that the isolated compound was fisetin. Based on the results that recessive c2 accumulates a C9 compound and the present observation that recessive r-r accumulates C15 compounds, chalcone and flavonol, further confirm the position of R after C2 in the gene action sequence. These observations have provided insight into the control of specific gene-product relationships and also the position of genes in the control of anthocyanin biosynthesis in maize.

V. Satyanarayana and G.M. Reddy
 
 

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