Tag : Enzymes

Washington: A research team shows in a new study how leaf beetles could successfully use new and previously indigestible food sources in the course of evolution. The insects acquired enzymes from microorganisms via horizontal gene transfer that enabled them to degrade pectins, solid components of the plant cell wall. Since the degradation products resulting from pectin digestion are not per se crucial for the growth and development of the beetles, the researchers conclude that the beetles disrupt the cell wall to access the protein-rich cytoplasm of plant cells, which they need for their nutrition. Fossil findings of insect feeding damage on plants are evidence that insects have been using plants as a food source for more than 400 million years. Researchers led by Roy Kirsch and Yannick Pauchet from the Department of Insect Symbiosis are investigating how herbivorous insects are able to break down the hard-to-digest components of their plant food in the first place. In earlier work, they had already shown that pectin-degrading enzymes are widespread in herbivorous beetle species. They were also able to demonstrate that these beetle enzymes were invariably of microbial origin. The question of the current study was therefore how important these enzymes are for the nutrition and fitness of the insect, in this case the mustard leaf beetle Phaedon cochleariae. "Our goal was to better understand how herbivorous insects deal with the plant cell wall, which makes the bulk of their diet. Pectin is the matrix embedding cellulose and hemicellulose fibers within the plant cell wall, and it is the main constituent of the cell-connecting middle lamellae. Consequently, pectin must be digested first so that cellulase and hemicellulase enzymes can ac ...