✍ Scribed by Robert Leah; John Mundy
No coin nor oath required. For personal study only.
We have cloned and sequenced a full-length cDNA from barley (Hordeum vulgate L.) seeds encoding the bifunctional ~-amylase/subtilisin inhibitor (BASI). The nucleotide sequence predicts an open reading frame coding for a protein of 203 amino acids. The first 22 amino acids exhibit the sequence characteristic of a signal peptide, as found in several other plant protease inhibitors. Northern blot hybridization experiments indicate that BASI mRNA accumulation is strictly tissue-specific and is developmentally programmed. BASI mRNA transcripts were only identified in 1) developing starchy endosperm tissue from 14 days after flowering and 2) aleurone tissue of germinating seeds. In this latter tissue, BASI mRNA accumulation is enhance d by abscisic acid and abolished by gibberellic acid. Expression of BASI mRNA was also studied in the lys 3a high-lysine barley mutants Ris~ No. 1508 and Piggy. These high-lysine barleys show 2-4-fold higher levels as well as prolonged accumulation of BASI mRNA compared to the normal motherline Bomi. This correlates with the increased deposition of BASI protein in lys 3a barley mutants. Genomic blot analysis of barley DNA suggests that there are one or two BASI structural genes per haploid genome. Possible roles of BASI as part of a defence mechanism against precocious germination and pathogens are discussed.
📜 SIMILAR VOLUMES
Changes in bifunctional alpha-amylase/subtilisin inhibitor (BASI) expression induced by abscisic acid (ABA) were studied using in vitro cultured barley (Hordeum vulgare cv. Bonanza) embryos. The steady-state levels of BASI mRNA and BASI protein were increased by exogenously applied ABA. Accumulation
The primary structure of the insect alpha-amylase inhibitor CMa of barley seeds was deduced from a full-length cDNA clone pc43F6. Analysis of RNA from barley endosperm shows high levels 15 and 20 days after flowering. The cDNA predicts an amino acid sequence of 119 residues preceded by a signal pept
Three cDNA clones from barley developing endosperm, corresponding to proteins BTAI-CMa, BTAI-CMb and BTAI-CMd, which are the three types of subunits of the tetrameric inhibitor of insect c~-amylases, have been identified and sequenced. The deduced amino acid sequence of BTAI-CMb corresponds to the C