Cell wall modifications Numerous genes involved in cell wall remodeling were shown to be differentially expressed after infection with M. incognita. Genes encoding four members of the expansin enzyme family were up regulated Inhibitors,Modulators,Libraries at both time points. Also, genes encoding endo 1,3 beta glucanase family members were differentially expressed. Most of them were up regulated, while one member was down regulated 27 fold in the 12 dai and 44 fold in the 10 wai. A gene encoding the cell wall modifying xyloglucan endotransglycosylase hydrolase was down regulated at both time points, while the gene encoding endoxyloglucan transferase A2 was up regulated at both time points. Expression of a gene encoding pectin esterase increased 24 fold and 47. 5 fold at 12 dai and 12 wai, respectively.
In addition, a gene encoding cellulose synthase was down regulated by 9. 3 fold and 4. 5 Inhibitors,Modulators,Libraries fold at 12 dai and 10 wai, Drug_discovery respectively. Also, in phenylpropanoid biosynthesis, genes encoding a family of 21 extensin peroxidases that participate in lignin biosynthesis were differentially regu lated. The extensin gene with the highest increase in expression increased by 95 fold while the extension gene with the largest decrease in expression decreased by 16 fold. Carbon and energy metabolism The expression of numerous genes encoding enzymes in glycolysis, the tricarboxylic acid cycle and in amino sugar synthesis was altered. For example, the gene encoding UDP glucuronate 4 epimerase was greatly down regulated with a 21 fold decrease in tran script abundance. Also, the gene encoding GDP man nose 4,6 dehydratase was down regulated 20.
5 and 5. 3 fold at 12 dai and 10 wai. In the glycolysis pathway, many genes were up regulated during infection, including genes encoding glucose 6 phosphate Inhibitors,Modulators,Libraries isomerase, transcripts of which were increased by 14 fold at 12 dai Defense related genes There are multiple changes in expression of genes encoding enzymes of the alpha linolenic acid pathway leading to several important defense related compounds, including jasmonic acid. At 12 dai, the change in expression of genes encoding enzymes leading Inhibitors,Modulators,Libraries to jas monic acid seems conflicting. For example, the gene encoding palmitoyl CoA hydrolase, an enzyme that is needed for the biosynthesis of the alpha linolenic acid, is suppressed. Linolenic acid can be a substrate for lipoxygenase.
Genes encod ing six lipoxygenase family members were differentially expressed. Mostly of them were up regulated with high est induction of 22 fold for one member. One gene family member was down regu lated by 3. 8 fold. In addition, some gene family mem bers encoding allene oxide synthase, leading to jasmonic acid synthesis, were up regulated, while others were down regulated. The abundance of transcripts of the gene encoding the next enzyme in the pathway, allene oxide cyclase was also decreased. Yet, a gene encoding OPDA reductase was up regu lated.