Cross feeding and pigment synthesis in root cultures

In view of the several advantages of somatic cell genetics, a study of genetically defined marker systems with well understood biosynthetic pathways like anthocyanin synthesis in maize may help in understanding the mechanisms of gene action at a cellular level with different explant tissues. Among the different explants used for initiating callus cultures, seedling root was found to be more efficient and was used in the present study. Callus cultures were derived from seedling root of anthocyanin genotypes on LS medium with 2,4-D. After a few subcultures, a few sectors of the calli and the regenerated roots exhibited pigment formation. The callus/root extracts of different genotypes in 1% methanolic HCl gave absorption maxima of 530 nm in the Pr genotype, 520 nm in the pr genotype, and 210 and 260 nm in the c2 genotype, suggesting that the accumulation of pigments may be cyanidin, pelargonidin and cinnamic acid respectively.

To gain insight into the gene-controlled pathway of anthocyanin biosynthesis, cross-feeding studies were conducted with root cultures of certain genotypes. Various substances like cinnamic acid, coumaric acid, caffeic acid, naringenin and quercetin were supplemented to the medium, and seedling roots of different genotypes were callused.

Immature kernels of C-I were allowed to germinate in the presence of caffeic acid supplemented medium. Roots were dissected out from such seedlings and callus was initiated on LS medium with 2,4-D. After a month, root calli were transferred to LS basal medium. Purple pigment was observed in the regenerated roots, suggesting that C-I may utilize caffeic acid in the synthesis of anthocyanin. Further studies with C-I and other mutants are in progress.

K. V. Rao, P. Suprasanna and G. M. Reddy


Please Note: Notes submitted to the Maize Genetics Cooperation Newsletter may be cited only with consent of the authors.

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