Proteinase inhibitors are ubiquitous in legumes and other plant species. They are considered to be antinutritional factors affecting animal digestion and/or growth, but they can also represent a natural defence that helps protect plants from attacks by insects, pathogens and other predators. The plant serine protease inhibitors constitute a number of structurally distinct families. Among these families, the Bowman-Birk trypsin inhibitors (BBIs) are small polypeptides, typically found in several leguminous species. They have a duplicated structure and are generally double-headed inhibitors, therefore they can inhibit two different proteases per inhibitor molecule. These inhibitors are also interesting for the study of host-pathogen co-evolution, as regulators of endogenous enzymes and as markers in studies on plant evolution and diversification (3). Moreover, reports in the last decade show a possible involvement of BBI in the prevention of tumorigenesis in vitro (2). Investigating orthologous genes and proteins can be very useful to understand their functional similarities and differences as well as to achieve information on their evolution. When working with multigene families, such as BBIs, the problem is to compare orthologous genes between related taxa, paying attention to avoid paralogous comparisons, which are illegitimate. In pea, the major seed trypsin inhibitor exists in multiple isoforms that can be attributed to post-translational modifications of primary gene products (1). Forward and reverse nucleotide primers were designed in different positions of two pea BBIs genes and were used to amplify orthologous regions in the cultivated lentil and its wild relatives. By comparing BBIs gene coding and presumed protein sequences in the genus Lens we ascertained the presence of two different classes of BBIs in lentil, which were orthologous to the two pea BBIs classes from which the primer sequences were obtained. Both nucleotide and protein sequences were similar within each of the two classes, even though the species L. nigricans showed a lower degree of similarity. As expected, there was a higher difference between paralogous lentil sequences than between orthologous sequences from different species of the genus Lens.
Trypsin inhibitor coding sequences in lentil and its wild relatives
Sonnante G;De Paolis A;Pignone D
2004
Abstract
Proteinase inhibitors are ubiquitous in legumes and other plant species. They are considered to be antinutritional factors affecting animal digestion and/or growth, but they can also represent a natural defence that helps protect plants from attacks by insects, pathogens and other predators. The plant serine protease inhibitors constitute a number of structurally distinct families. Among these families, the Bowman-Birk trypsin inhibitors (BBIs) are small polypeptides, typically found in several leguminous species. They have a duplicated structure and are generally double-headed inhibitors, therefore they can inhibit two different proteases per inhibitor molecule. These inhibitors are also interesting for the study of host-pathogen co-evolution, as regulators of endogenous enzymes and as markers in studies on plant evolution and diversification (3). Moreover, reports in the last decade show a possible involvement of BBI in the prevention of tumorigenesis in vitro (2). Investigating orthologous genes and proteins can be very useful to understand their functional similarities and differences as well as to achieve information on their evolution. When working with multigene families, such as BBIs, the problem is to compare orthologous genes between related taxa, paying attention to avoid paralogous comparisons, which are illegitimate. In pea, the major seed trypsin inhibitor exists in multiple isoforms that can be attributed to post-translational modifications of primary gene products (1). Forward and reverse nucleotide primers were designed in different positions of two pea BBIs genes and were used to amplify orthologous regions in the cultivated lentil and its wild relatives. By comparing BBIs gene coding and presumed protein sequences in the genus Lens we ascertained the presence of two different classes of BBIs in lentil, which were orthologous to the two pea BBIs classes from which the primer sequences were obtained. Both nucleotide and protein sequences were similar within each of the two classes, even though the species L. nigricans showed a lower degree of similarity. As expected, there was a higher difference between paralogous lentil sequences than between orthologous sequences from different species of the genus Lens.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
