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: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)
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.
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:During a compatible interaction, root-knot nematodes (Meloidogyne spp.) induce the redifferentiation of root cells into multinucleate nematode feeding cells giant cells. These hypertrophied cells result from repeated nuclear divisions without cytokinesis, are metabolically active and present features typical of transfer cells. Hyperplasia of the surrounding cells leads to formation of the typical root gall. We investigate here the plant response to root-knot nematodes.
Project description:Biotrophic plant pathogens have evolved sophisticated strategies to manipulate their host. They derive all of their nutrients from living plant tissues, by making intimate contact with their host while avoiding a resistance response. Rice is one of the most important crop plants worldwide and an excellent model system for studying monocotyledonous plants. Estimates of annual yield losses due to plant-parasitic nematodes on this crop range from 10 to 25% worldwide. One of the agronomically most important nematodes attacking rice is the rice root knot nematode Meloidogyne graminicola. Attack of plant roots by sedentary plant parasitic nematodes, like the root knot nematodes (RKN; Meloidogyne spp.) involves the development of specialized feeding cells in the vascular tissue. The second stage juvenile of the RKN punctures selected vascular cells with its stylet, injects pharyngeal secretions, and this ultimately leads to the reorganisation of these cells into typical feeding structures called giant cells (GCs), from which the nematode feeds for the remainder of its sedentary life cycle (Gheysen & Mitchum, 2011). Morphological and physiological reprogramming of the initial feeding cell leads to nucleus enlargement, proliferation of mitochondria and plastids, metabolic activation, cell cycle alterations and cell wall changes (Gheysen and Mitchum, 2011). The hyperplasia and hypertrophy of the surrounding cells leads to the formation of a root gall, which is typically formed at the root tips in the case of the rice RKN M. graminicola. In comparison with other RKN, M. graminicola has a very fast life cycle, with swelling of the root tips observed as early as 1 day after infection (dai). At 3 dai, terminal hook-like galls are clearly visible (Bridge et al., 2005). After 3 moults the nematodes are mature, around 10 dai. The M. graminicola females lay their eggs inside the galls, while most other RKN deposit egg masses at the gall surface, and hatched juveniles can reinfect the same or adjacent roots. In well-drained soil at 22-29 degrees C the life cycle of M. graminicola is completed in 19 days. 2 biological replicates of nematode infected giant cells and control vascular cells were sampled at two time points: 7 and 14 dai
Project description:The aim of this study was to elucidate the molecular basis underlying the compatible interaction between potato and root-knot nematode at early stages on infection at 3 and 7dpi.