Although work on the prolamins of pearl millet (Pennisetum glaucum) has revealed partial amino acid sequences for several alcohol-soluble storage proteins (Marcellino et al. 2002) the genes encoding them have not yet been isolated. We constructed a cDNA library from developing P. glaucum seed tissue and screened it using maize zein gene probes to isolate several α-prolamin-like gene sequences. The proteins encoded by these genes generally fall into two size classes: 20.6kD and 27.1kD, which we call the 21kD and 27kD pennisetins. Both proteins are similar in composition and sequence to α-prolamins from maize, sorghum and Coix. Protein bodies that appear as occlusions within the rough ER of P. glaucum endosperm cells are also very similar in size and shape to maize and sorghum protein bodies. The SDS-PAGE gel of the alcohol soluble protein fraction shows two distinct bands in the region corresponding to the 19kD and 22kD of maize α-zein. Both classes of pennisetins appear to be more similar to the 19kD α-zein of maize than to the 22-kD α-zein judging from sequence homology and maize antibody binding. Phylogenetic reconstruction suggests that P. glaucum may have branched from maize prior to the gene duplication which created the 19kD and 22kD α-zein families.



College and Department

Life Sciences; Plant and Wildlife Sciences



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prolamins, pennisetins, pearl millet, zein, kafirin, coixins, maize, seed storage proteins, endosperm, agriculture, cereal crops, grain improvement, nutrition