Moreover, down regulation of genes encoding cellulose synthase and over expression of genes encod ing pectin esterase that degrades pectin to pectate PD173955? coin cide with a breakdown of the cell wall during the early time points of infection with Meloidogyne. Our results are consistent with those of Jammes et al. who found genes encoding pectin esterases and pectate lyases were activated in Arabidopsis thaliana roots after infec tion with Meloidogyne incognita and the cell wall loos ening Inhibitors,Modulators,Libraries process was activated during the development of the giant cell as well. In giant cells formed in tomato by M. javanica, there is an 8 fold and 7. 3 fold increase in expression of the gene encoding pectinesterase U1 pre cursor. Giant cells formed by M. javanica in roots of Arabidopsis were collected by LCM and analyzed by Barcala et al.
Genes encoding cellulose synthase, expansin, pectate lyase, endoxyloglucan transferase also were all up regulated in these cells Inhibitors,Modulators,Libraries coinciding with cytoskeleton rearrangements that occur during giant cell development. Nutrients supply for M. incognita The nematode uses a large amount Inhibitors,Modulators,Libraries of plant resources to develop and reproduce. This demand for energy and carbon is reflected in the numerous genes involved in glycolysis and gluconeogenesis that are up regulated in the soybean root. For example, we found many genes encoding enzymes in the glycolysis pathway and amino sugar synthesis to be up regulated. Mostly, the changes in gene expression occurred early in infec tion. In addition to their roles in pathways that provide energy and carbon for the nematode, some of these genes have an essential role in the soybean M.
incognita interaction. For example, at 12 dai, the gene encoding UDP glucuronate 4 epimerase is highly down regulated. In Arabidopsis, a mutation in this gene resulted in hyper sensitivity Inhibitors,Modulators,Libraries to the cyst nematode, Heterodera schachtii. In Azospiril lum brasilense, this enzyme is important for lipopolysac charide Inhibitors,Modulators,Libraries synthesis which is important in the bacterium plant root interaction. A mutation in this gene resulted in the failure of the bacteria to respond to several stres ses and antimicrobial compounds. It also affected the ability of the bacteria to form biofilms. This enzyme may be important in allowing the host to respond to M. incognita invasion. In the glycolysis and gluconeogenesis pathways, many genes were shown to be up regulated, including the gene encoding glucose 6 phosphate isomerase.
The gene encoding this Calcitriol IL-2 enzyme was also shown to be up regulated in cucumber plants after treatment with Trichoderma asperrellum T34. The enzyme is essential in salinity tolerance in the alga Dunaliella sal ina. Not only do nematodes require large quantities of car bon and energy from its host, they also use starch dur ing juvenile development. Starch is stored in syncytia formed by Heterodera schachtii in roots of Arabidopsis.