The prolamin polypeptides of maize and related grasses

Seven tropical maize inbred lines, four teosinte varieties (Zea luxurians, Zea mays mexicana, Zea mays parviglumis and Zea diploperennis), Tripsacum dactyloides and Coix lacryma-jobi had their alcohol soluble proteins analysed by SDS-PAGE and isoelectric focusing (IEF) on agarose gels. On SDS-PAGE the prolamins of the maize inbred lines, teosinte varieties and Tripsacum were separated into the well-known four major size classes with apparent molecular weight of 22, 19, 15 and 10 kD. The prolamin of Coix presented a band with apparent molecular weight of 22 kD, along with a band of higher molecular weight, and an intermediary band between the 15 and 10 kD classes.

The IEF analysis showed distinct prolamin profiles ("fingerprints") for all samples analysed. In the seven maize inbred lines a total of 25 different polypeptides were identified. The polypeptides were numbered according to their distance to the cathode end of the gels (Wilson, Cereal Chem. 61:198-200, 1984). The most basic polypeptide found among the maize inbred lines was 10, and the most acidic was 47.5. Polypeptides 25.5, 31 and 35 were present in all the inbred lines.

A great heterogeneity was observed among the IEF pattern of Coix, Tripsacum and the teosinte varieties. The most basic band identified was 7.5. That band was present in Tripsacum and Zea diploperennis. The most acidic band was found in Zea mays parviglumis and was designated 58. Both bands, 7.5 and 58, were not present in the maize inbred lines analysed. Polypeptides 31 and 35, which were identified in all the seven maize inbred lines, were also found in Tripsacum and teosinte. Those polypeptides could be the product of genes that were conserved during evolution. This, however, should be confirmed by molecular analyses of those genes.

Laura M.M. Ottoboni and Paulo Arruda

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

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