Characterisation of storage protein from selected varieties of foxtail millet (Setaria italica (L) Beauv)

Abstract

Protein content of the three selected varieties of Setaria italica (L) Beauv ranged from 91·7 to 112·0 g kg−1. Fractionation of seed protein showed that prolamin is the major storage protein and the differences in protein content among them is mainly due to differences in the total prolamin accumulation. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) pattern of different protein fractions; namely, albumin/globulin, prolamins and glutelins and RP-HPLC (reversed-phase high-performance liquid chromato-graphy) of the total prolamins showed great similarity among the three selected varieties. Accumulation of total protein and protein fractions during seed maturation was studied in all the three selected varieties. Fractionation of total protein in the grain collected at 5, 10, 15, 20, 25, 36 days after anthesis revealed that prolamin is the major storage protein ( > 50% of total protein) during all the stages of seed development. The SDS-PAGE pattern of the total prolamin at different stages of seed development showed no variation among the selected varieties. Prolamin polypeptide synthesis commenced as early as 5 days after flowering (DAF) and completed before 10 DAF. Thereafter, only quantitative increase was observed. Immunoblotting of the total prolamin from S italica probed with 20 kDa prolamin protein antibody of kodo millet (Paspalum scrobiculatum) showed that the two millets are immunologically related to one another. © 1998 SCI.