Project description:Background: The oomycete Phytophthora infestans possesses active RNA silencing pathways, which presumably enable this plant pathogen to control the large numbers of transposable elements present in its 240 Mb genome. Small RNAs (sRNAs), central molecules in RNA silencing, are known to also play key roles in this organism, notably in regulation of critical effector genes needed for infection of its potato host. Results: To identify additional classes of sRNAs in oomycetes, we mapped deep sequencing reads to transfer RNAs (tRNAs) thereby revealing the presence of 19-40 nt tRNA-derived RNA fragments (tRFs). Northern blot analysis identified abundant tRFs corresponding to half tRNA molecules. Some tRFs accumulated differentially during infection, as seen by examining sRNAs sequenced from P. infestans-potato interaction libraries. The putative connection between tRF biogenesis and the canonical RNA silencing pathways was investigated by employing hairpin RNA-mediated RNAi to silence the genes encoding P. infestans Argonaute (PiAgo) and Dicer (PiDcl) endoribonucleases. By sRNA sequencing we show that tRF accumulation is PiDcl1-independent, while Northern hybridizations detected reduced levels of specific tRNA-derived species in the PiAgo1 knockdown line. Conclusions: Our findings extend the sRNA diversity in oomycetes to include fragments derived from non-protein-coding RNA transcripts and identify tRFs with elevated levels during infection of potato by P. infestans. Small RNA sequence data from Phytophthora infestans-infected potato leaf tissue and P. infestans mycelium tissue. Three infection stage time-points. Two P. infestans lines: 88089 (wild-type) and PiDcl1 (transformant PiDcl1 knock-down). No replicates. Total number of samples: 8.
Project description:Background: The oomycete Phytophthora infestans possesses active RNA silencing pathways, which presumably enable this plant pathogen to control the large numbers of transposable elements present in its 240 Mb genome. Small RNAs (sRNAs), central molecules in RNA silencing, are known to also play key roles in this organism, notably in regulation of critical effector genes needed for infection of its potato host. Results: In order to identify additional classes of sRNAs in oomycetes, we mapped deep sequencing reads to transfer RNAs (tRNAs) thereby revealing the presence of 19-40 nt tRNA-derived RNA fragments (tRFs). Northern blot analysis identified abundant tRFs corresponding to half tRNA molecules. Some tRFs accumulated differentially during infection, as seen by examining sRNAs sequenced from P. infestans-potato interaction libraries. The putative connection between tRF biogenesis and the canonical RNA silencing pathways was investigated by employing hairpin RNA-mediated RNAi to silence the genes encoding P. infestans Argonaute (PiAgo) and Dicer (PiDcl) endoribonucleases. By sRNA sequencing we show that tRF accumulation is PiDcl1-independent, while Northern hybridizations detected reduced levels of specific tRNA-derived species in the PiAgo1 knockdown line. Conclusions: Our findings extend the sRNA diversity in oomycetes to include fragments derived from non-protein-coding RNA transcripts and identify tRFs whose levels are elevated during infection of P. infestans on potato. Small RNA sequence data from two Phytophthora infestans isolates. Four life-cycle stages from each isolate. No replicates. Total number of samples: 8.
Project description:Background: The oomycete Phytophthora infestans possesses active RNA silencing pathways, which presumably enable this plant pathogen to control the large numbers of transposable elements present in its 240 Mb genome. Small RNAs (sRNAs), central molecules in RNA silencing, are known to also play key roles in this organism, notably in regulation of critical effector genes needed for infection of its potato host. Results: To identify additional classes of sRNAs in oomycetes, we mapped deep sequencing reads to transfer RNAs (tRNAs) thereby revealing the presence of 19-40 nt tRNA-derived RNA fragments (tRFs). Northern blot analysis identified abundant tRFs corresponding to half tRNA molecules. Some tRFs accumulated differentially during infection, as seen by examining sRNAs sequenced from P. infestans-potato interaction libraries. The putative connection between tRF biogenesis and the canonical RNA silencing pathways was investigated by employing hairpin RNA-mediated RNAi to silence the genes encoding P. infestans Argonaute (PiAgo) and Dicer (PiDcl) endoribonucleases. By sRNA sequencing we show that tRF accumulation is PiDcl1-independent, while Northern hybridizations detected reduced levels of specific tRNA-derived species in the PiAgo1 knockdown line. Conclusions: Our findings extend the sRNA diversity in oomycetes to include fragments derived from non-protein-coding RNA transcripts and identify tRFs with elevated levels during infection of potato by P. infestans.
Project description:Phytophthora infestans is most notorious oomycete causing a devastating disease on tomato called late blight. The molecular mechanisms involved in host-parasite interaction is still unexplored well. Investigation of changes in gene expression profile after pathogen infection to find out the mechanisms involved in infection process Second full expanded leaves from both healthy tomato plants (non-inoculated) and diseased tomato plants inoculated with Phytophthora infestans inoculum were used to extract total RNA for microarry analysis 12 hours post inoculation time.
Project description:Background: The oomycete Phytophthora infestans possesses active RNA silencing pathways, which presumably enable this plant pathogen to control the large numbers of transposable elements present in its 240 Mb genome. Small RNAs (sRNAs), central molecules in RNA silencing, are known to also play key roles in this organism, notably in regulation of critical effector genes needed for infection of its potato host. Results: In order to identify additional classes of sRNAs in oomycetes, we mapped deep sequencing reads to transfer RNAs (tRNAs) thereby revealing the presence of 19-40 nt tRNA-derived RNA fragments (tRFs). Northern blot analysis identified abundant tRFs corresponding to half tRNA molecules. Some tRFs accumulated differentially during infection, as seen by examining sRNAs sequenced from P. infestans-potato interaction libraries. The putative connection between tRF biogenesis and the canonical RNA silencing pathways was investigated by employing hairpin RNA-mediated RNAi to silence the genes encoding P. infestans Argonaute (PiAgo) and Dicer (PiDcl) endoribonucleases. By sRNA sequencing we show that tRF accumulation is PiDcl1-independent, while Northern hybridizations detected reduced levels of specific tRNA-derived species in the PiAgo1 knockdown line. Conclusions: Our findings extend the sRNA diversity in oomycetes to include fragments derived from non-protein-coding RNA transcripts and identify tRFs whose levels are elevated during infection of P. infestans on potato.
Project description:In both plants and animals, alternative splicing (AS) increases transcriptome and proteome diversity, and play roles in developmental and immune responses. However, the extent of host genome-wide AS changes and how these changes are modulated by adaptive pathogens during disease remain largely unknown. Here we examined AS changes in Phytophthora infestans infected Solanum lycopersicum leaves using paired-end illumina RNA-seq. Quite a number of AS events are independent of gene differential expression, indicating that AS changes may be an additional layer of plant immunity against pathogens. we also demonstrated that P. infestans regulates plant immunity by repressing the AS of positive regulator of plant immunity or activating the AS of susceptibility factor. Furthermore, we established a splicing reporter system and screened some P. infestans splicing regulatory effectors (SREs) that are involved in plant mRNA alternative splicing process. In addition, we demonstrated that the WY motif of SRE3 is required for AS activity and virulence function. Overall, our current data reveal that P. infestans delivers SREs to disrupts host AS regulation machinery and subsequently suppress host immunity.
Project description:Phytophthora infestans is most notorious oomycete causing a devastating disease on tomato called late blight. The molecular mechanisms involved in host-parasite interaction is still unexplored well. Investigation of changes in gene expression profile after pathogen infection to find out the mechanisms involved in infection process
Project description:The oomycete potato blight pathogen Phytophthora infestans secretes a diverse set of proteins to manipulate host plant immunity. However, there is limited knowledge about the role(s) of majority of these secreted proteins. Here we subjected extracellular proteins from in vitro cultured hyphae to LC/MS/MS to investigate the cargo of protein secretion pathways in P. infestans, in particular the conventional secretory pathway. Like the apoplastic effector EPIC1 (a cysteine protease inhibitor), we show that secretion of cell wall degrading enzymes and pathogen associated molecular pattern (PAMP)-like proteins is inhibited by brefeldin A (BFA) in vitro and in planta, demonstrating that these proteins are secreted by the conventional, Golgi-mediated pathway. For comparison, an RXLR (Arg-any amino acid-Leu-Arg) effector, Pi22926, was shown to be unconventionally secreted at haustoria, pathogen structures that penetrate host plant cells, and delivered into infected cells to suppress host defences, consistent with previous findings. We further characterised a pectinesterase (PE), a cell wall degrading enzyme, and INF4, a PAMP-like protein. Both were highly expressed early in infection, enhanced P. infestans colonization, and secreted at haustoria. Notably, in P. infestans transformed lines, PE-mRFP accumulated around the base of haustoria while INF4-mRFP was found to envelop the whole haustorium. We propose that the haustorium is a major site for both non-conventional and conventional secretion, and cell wall degrading enzymes and PAMP proteins are secreted at these sites to facilitate pathogenicity in P. infestans.