Magnaporthe oryzae is the causative agent of the rice blast, the most relevant rice disease worldwide. To date expression analysis on rice infected with Magnaporthe oryzae have been carried out only with the strains FR13 (leaf) and Guy 11 (root). However different strains of Magnaporthe are present in the environment leading to different rice responses at molecular level. To gain more insight on the unknown molecular mechanisms activated by different Magnaporthe strains during rice defense, a global expression analysis was performed by using the GeneChip Rice Genome Array.
OsWRKY22, a monocot WRKY gene, plays a role in the resistance response to blast.
Specimen part
View SamplesPowdery mildew is a very common plant disease and only few plants are immune. Host interactions have been identified and characterized for the pathosystems barley-B. graminis f. sp. tritici (Bgt) and wheat-B. graminis f. sp. hordei (Bgh), whereas no data are reported about powdery mildew and nonhost plants, such as rice. On the other hand rice nonhost resistance is widely unexploited and only few expression data are available. To characterize rice response during nonhost interaction with Bgh, a global expression analysis was performed by using the GeneChip Rice Genome Array.
OsWRKY22, a monocot WRKY gene, plays a role in the resistance response to blast.
Specimen part
View SamplesC. elegans has served as a laboratory model organism due to its ease of manipulation and the availability of both forward and reverse genetics. In recent years, efforts to study host-pathogen interactions in C. elegans have increased. For example, analysis of infections by bacteria such as Pseudomonas, Salmonella or Serratia has revealed the existence of innate immune pathways in C. elegans that are also conserved in vertebrates. To date, there has been no natural virus infection reported in C. elegans or C. briggsae. Here we describe evidence of natural virus infection in wild isolates of both C. elegans and C. briggsae. Two highly divergent but related RNA viruses in the family Nodaviridae, tentatively named Orsay nodavirus and Santeuil nodavirus, were detected and their genomes partially sequenced. Infected worm lysates passed through 0.2 um filters could be used to infect uninfected worms, which could be further passaged for many generations. Furthermore, the viruses were subject to processing by the RNAi machinery as evidenced by the detection of virally derived small RNAs. Infection of mutant worms defective in small RNA pathways yielded more robust levels of viral RNA as compared to infection of isogenic N2 reference worms. These data demonstrate that nodaviruses are natural parasites of nematodes in the wild. Further study of the interactions between these viruses and nematodes is likely to provide insight into the natural ecology of nematodes and may reveal novel innate immune mechanisms that respond to viral infection. Overall design: Two small RNA libraries (18-30 nt) from nodavirus-infected and cured C. elegans wild isolate JU1580 were sequenced on the Illumina Genome Analyzer II platform. Samples were treated with tobacco acid pyrophosphatase to allow cloning of small RNA molecules with 5'-triphosphates. Each sample was labelled with a unique four base pair barcode and libraries were multiplexed together with a third library (not included in this submission). The multiplexed libraries were sequenced in triplicate.
Natural and experimental infection of Caenorhabditis nematodes by novel viruses related to nodaviruses.
Subject
View SamplesGrainyhead genes are involved in wound healing and developmental neural tube closure. In light of the high degree of similarity between the epithelial-mesenchymal transitions (EMTs) occurring in wound healing processes and the cancer stem cell-like compartment of tumors, including TGF--dependence, we investigated the role of a Grainyhead gene (GRHL2) in oncogenic EMT. Grainyhead was specifically down-regulated in the claudin-low subclass of mammary tumors and in the basal-B subclass of breast cancer cell lines. Functionally, GRHL2 suppressed TGF--induced, Twist-induced or spontaneous EMT, enhanced anoikis-sensitivity, and suppressed mammosphere generation in mammary epithelial cells. These effects were mediated, in part, by its suppression of ZEB1 expression, through direct repression of the ZEB1 promoter. GRHL2 also inhibited Smad-mediated transcription, and up-regulated mir200b/c as well as the TGF- receptor antagonist, BMP2. The expression of GRHL2 in the breast cancer cell line MDA-MB-231 triggered a mesenchymal-to-epithelial transition and sensitized the cells to anoikis. These results indicate that GRHL2 is a suppressor of the oncogenic EMT.
Suppression of the epithelial-mesenchymal transition by Grainyhead-like-2.
Specimen part
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