CHARACTERIZATION OF 10 KDA PROLAMIN GENES IN PHYLLOSTACHYS-AUREA (BAMBUSOIDEAE, POACEAE)

Prolamin is the dominant class of seed storage protein in grasses (Poa ceae). Information on the 10 kDa multigene family coding for prolamins characteristic of the bambusoid-oryzoid grasses is limited. Two genes encoding 10 kDa prolamin were cloned and sequenced in the bambusoid s pecies Phyllostachys aurea to assess the sequence diversity of this ge ne family in the oryzoid-bambusoid grasses. The genes, similar to 417 bp in length, were 96% Similar at the DNA sequence level, differing in 12 base substitutions dispersed throughout the sequence. Eight of the se mutations were nonsynonymous, leading to amino acid substitutions i n the coding region, and one was nonsense, producing an amber stop cod on. One gene had an open reading frame (ORF) of 139 amino acids, while the other gene had a shorter ORF (106 amino acids) due to the presenc e of a stop codon in the coding region and, thus, represents a pseudog ene. Deduced proteins showed amino acid composition similar to that of rice. The study underscores the overall conserved nature of this mult igene family and reflects considerable sequence divergence at the DNA and amino acid levels between the Oryza and the Phyllostachys genes. T he systematic implication of the data is discussed in light of the inc onsistent placement of Oryza in the Bambusoideae or Oryzoideae.