Project description:Phosphate starvation/sufficient rice seedling, root or shoot Pi-starvation or Pi-sufficient stresses responsible rice genes, including previously unannotated genes were identified by Illumina mRNA-seq technology. 53 million reads from Pi-starvation or Pi-sufficient root or shoot tissues were uniquely mapped to the rice genome, and these included 40574 RAP3 transcripts in root and 39748 RAP3 transcripts in shoot. We compared our mRNA-seq expression data with that from Rice 44K oligomicroarray, and about 95.5% (root) and 95.4% (shoot) transcripts supported by the array were confirmed expression both by the array and by mRNA-seq, Moreover, 11888 (root) and 11098 (shoot) RAP genes which were not supported by array, were evidenced expression with mRNA-seq. Furthermore, we discovered 8590 (root) and 8193 (shoot) previously unannotated transcripts upon Pi-starvation and/or Pi-sufficient.
Project description:Contrary to the relative wealth of information regarding pathogen defense responses in aboveground plant parts, little is known about the mechanistic basis and regulation of plant immunity in root tissues. Aiming to further our fundamental understanding of root immune responses, we have investigated the interaction between rice and one of its major root pathogens, the oomycete Pythium graminicola. The specificic objectives of this study were twofold: i) to disentangle the molecular and genetic basis of the rice-Pythium interaction by comparing the transcriptome of rice roots at different times after inoculation with a highly virulent Pythium strains, and ii) to offer fundamental insights into the genetic architecture and regulation of rice disease resistance pathways operative in root tissue and to identify the molecular players controlling the possible nodes of convergence between these resistance conduits Comparison between P. graminicola- and mock-infected rice roots. Two treatments (infected and non-infected) x three timepoints (1, 2 and 4 days post inoculation) x three biological replicates
Project description:Next to their essential roles in plant growth and development, phytohormones play a central role in plant immunity against pathogens. In this study we examined the role of hormones in the antagonism of the plant-pathogenic oomycete Pythium arrhenomanes against the root-knot nematode Meloidogyne graminicola in rice roots. Hormone measurements and gene expression analyses showed that the jasmonate (JA) pathway is induced early upon P. arrhenomanes infection. Exogenous application of methyl-jasmonate (MeJA) on the plant confirmed that JA is needed for basal defence against both P. arrhenomanes and M. graminicola in rice. Whereas M. graminicola suppresses root JA levels to increase host susceptibility, Pythium inoculation boosts JA accumulation up to levels that can no longer be repressed by the nematode in double-inoculated plants. Exogenous MeJA supply phenocopied the defence-inducing capacity of P. arrhenomanes against the root-knot nematode, whereas the antagonism was weakened in JA-insensitive mutants. Transcriptome analysis confirmed upregulation of JA biosynthesis and signalling genes upon P. arrhenomanes infection, and additionally revealed induction of genes involved in biosynthesis of diterpenoid phytoalexins, consistent with strong activation of the gene encoding the JA-inducible transcriptional regulator DITERPENOID PHYTOALEXIN FACTOR. Next to that, our results provide evidence for induced expression of genes encoding ERF83, and related PR proteins, as well as auxin depletion in P. arrhenomanes infected rice roots, which potentially further contributes to the reduced nematode susceptibility seen in double-infected plants.
Project description:affy_meloidogyne_rice - affy_meloidogyne_rice - Plant-parasitic nematodes cause profound economic losses to global agriculture with the obligate sedentary endoparasitic varieties; amongst them the cyst and Root Knot Nematode (RKN) species are the most damaging. Meloidogyne graminicola is a RKN mainly found in the monocotyledous plants. In the compatible interaction with Oryza sativa, M. graminicola induces the characteristic formation of hook-like galls resulting from the redifferentiation of root cells into multinucleate giant cells. In order to understand the global transcriptome changes occurring during infection, several recent microarray studies on root knots have demonstrated complex changes in host plant gene expression in response to infection. However, to our knowledge, all these transcriptome studies were performed on dicotyledous plants. A histological study enabled us to observe hyperplasia and hypertrophy of the surrounding cells leading to the formation of hook-like galls. We also investigated the plant response to M. graminicola by carrying out a global analysis of gene expression during gall formation in rice, using giant cell-enriched root tissues at an early stage (2dpi) and a latter stage (4dpi) of gall development.-Oryza sativa (var. Nipponbare) seedlings were grown on 6 cm3 SAP substrate completed with diluted Hoaglands solution (Reversat et al., 1999). Culture units were placed in a growth chamber illuminated with fluorescent tubes 9/24 h and maintained at 23°C for 5 days before being inoculated with a 100 J2-stage juveniles M. graminicola. One day after inoculation (dai), the rice seedlings were immersed in de-ionised water to remove all J2s that had not penetrated the roots and allowing synchronization of the infection. Each seedling was transferred to a hydroponic mini chamber (Reversat et al., 2004). Sampling was performed at 2 and 4 dai and each of them contained galls from 70 infected plants, they were then hand-dissected, frozen in liquid-nitrogen and stored at -80°C. As reference samples, uninfected meristematic root fragments were dissected from seedlings grown under the same conditions. Each sample was replicated 3 times. Keywords: normal vs disease comparison,time course
Project description:Contrary to the relative wealth of information regarding pathogen defense responses in aboveground plant parts, little is known about the mechanistic basis and regulation of plant immunity in root tissues. Aiming to further our fundamental understanding of root immune responses, we have investigated the interaction between rice and one of its major root pathogens, the oomycete Pythium graminicola. The specificic objectives of this study were twofold: i) to disentangle the molecular and genetic basis of the rice-Pythium interaction by comparing the transcriptome of rice roots at different times after inoculation with a highly virulent Pythium strains, and ii) to offer fundamental insights into the genetic architecture and regulation of rice disease resistance pathways operative in root tissue and to identify the molecular players controlling the possible nodes of convergence between these resistance conduits
Project description:affy_meloidogyne_rice - affy_meloidogyne_rice - Plant-parasitic nematodes cause profound economic losses to global agriculture with the obligate sedentary endoparasitic varieties; amongst them the cyst and Root Knot Nematode (RKN) species are the most damaging. Meloidogyne graminicola is a RKN mainly found in the monocotyledous plants. In the compatible interaction with Oryza sativa, M. graminicola induces the characteristic formation of hook-like galls resulting from the redifferentiation of root cells into multinucleate giant cells. In order to understand the global transcriptome changes occurring during infection, several recent microarray studies on root knots have demonstrated complex changes in host plant gene expression in response to infection. However, to our knowledge, all these transcriptome studies were performed on dicotyledous plants. A histological study enabled us to observe hyperplasia and hypertrophy of the surrounding cells leading to the formation of hook-like galls. We also investigated the plant response to M. graminicola by carrying out a global analysis of gene expression during gall formation in rice, using giant cell-enriched root tissues at an early stage (2dpi) and a latter stage (4dpi) of gall development.-Oryza sativa (var. Nipponbare) seedlings were grown on 6 cm3 SAP substrate completed with diluted Hoaglands solution (Reversat et al., 1999). Culture units were placed in a growth chamber illuminated with fluorescent tubes 9/24 h and maintained at 23°C for 5 days before being inoculated with a 100 J2-stage juveniles M. graminicola. One day after inoculation (dai), the rice seedlings were immersed in de-ionised water to remove all J2s that had not penetrated the roots and allowing synchronization of the infection. Each seedling was transferred to a hydroponic mini chamber (Reversat et al., 2004). Sampling was performed at 2 and 4 dai and each of them contained galls from 70 infected plants, they were then hand-dissected, frozen in liquid-nitrogen and stored at -80°C. As reference samples, uninfected meristematic root fragments were dissected from seedlings grown under the same conditions. Each sample was replicated 3 times. Keywords: normal vs disease comparison,time course 9 arrays - rice
Project description:Transcriptional profiling of MIT knockdown plants. MIT is a mitochondrial Fe transporter essential for rice growth and development. The goal was to determine the effects of MIT on global rice gene expression.