Project description:Magnaporthe oryzae (rice blast) and the root-knot nematode Meloidogyne graminicola are causing two of the most important pathogenic diseases jeopardizing rice production. Here, we show that root-knot nematode infestation on rice roots leads to important above-ground changes in plant immunity gene expression, which is correlated with significantly enhanced susceptibility to blast disease.
Project description:We compared the gene expression of wild-type Col-0 and a T-DNA mutant SALK_116381C (opr2-1). We either infected or mock-infected the plants with the root knot nematode Meloidogyne incognita and measured the root transcriptome after 0, 1, 4, and 7 days post infection using RNA-seq. The aim of the experiment was to determine whether opr2-1 affected gene expression patterns induced by nematode infection.
Project description:High-coverage whole genome sequencing of 11 Brazilian isolates of the root-knot nematode Meloidogyne incognita, presenting different host plant preferences and different geographical origins. Four M. incognita host races had been proposed in the past, based on host (in)compatibility on four different plant strains. The objective was to assess whether genomic variations (SNP) correlate with host range compatibility, geographical origin and host plant of origin.
Project description:In this study a comparison was made between the local transcriptional changes at two time points upon root knot (Meloidogyne graminicola) and migratory nematode (Hirschmanniella oryzae) infection in rice. Using mRNA-Seq we have characterized specific and general responses of the root challenged with these endoparastic root nematodes with very different modes of action. Root knot nematodes induce major developmental reprogramming of the root tip, where they force the cortical cells to form multinucleate giant cells, resulting in gall-development. Our results show that root knot nematodes force the plant to produce and transfer nutrients, like sugars and amino acids, to this tissue. Migratory nematodes, on the other hand, induce the expression of proteins involved in plant death and oxidative stress, and obstruct the normal metabolic activity of the root. While migratory nematode infection also causes upregulation of biotic stress-related genes early in the infection, the root knot nematodes seem to actively suppress the local defence of the plant root. This is exemplified by a downregulation of genes involved in the salicylic acid and ethylene pathways. Interestingly, hormone pathways usually involved in plant development, were strongly induced (auxin and gibberellin) or repressed (cytokinin) in the galls. In addition, thousands of novel transcriptionally active regions as well as highly expressed nematode transcripts were detected in the infected root tissues. These results uncover previously unrecognized nematode-specific expression profiles and provide an interesting starting point to study the physiological function of many yet unannotated transcripts potentially targeted by these nematodes. 2 or 3 biological replicates of nematode infected roots and root tips and their respective controls were sampled at two time points (1 biological replicate contains pooled tissue from 6 plants)
