Project description:Phytophthora spp. encode large sets of effector proteins and distinct populations of small RNAs (sRNAs). Reports suggest that pathogen-derived sRNAs can modulate the expression of plant defense genes. The experiments reported here were designed to shed light on impact of sRNAs in the potato-P. infestans interaction. We used the Argonaute or Ago1 from P. infestans tagged with GFP transformed into the 88069 strain to infect potato cv. Bintje plants. Collected leaf materials were used in co-immunoprecipitation experiments together with P. infestans harboring GFP (control GFP) and P. infestans mycelia grown on media (control mycelia). These three materials were sequenced at a Ion Proton platform. The reads length of 8-38 nt were adaptor-trimmed and mapped to the P. infestans genome and the Solanom tuberosum genome v4.04. Both P. infestans-associated and potato derived sRNAs were identified.
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:Deep sequencing of small RNAs from three Phytophthora species, P. infestans, P. ramorum and P. sojae, was done to systematically analyze small RNA-generating components of Phytophthora genomes. We found that each species produces two distinct small RNA populations that are predominantly 21- or 25-nucleotides long. We present evidence that 25-nucleotide small RNAs are short-interfering RNAs that silence repetitive genetic elements. In contrast, 21-nucleotide small RNAs are associated with inverted repeats, including a novel microRNA family, and may function at the post-transcriptional level. Phytophthora infestans mycelium small RNAs were sequenced and aligned to the P. infestans genome for analysis.
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: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:The expression of genes in P. infestans isolates 06_3928A and NL07434 was monitored from 2 to 4 days time course of a potato infection. Genes encoding known and putative effector proteins were found induced at two and/or three days post-inoculation. We used a custom chip GPL8093 from Roche Nimblegen’s proprietary Maskless Array Synthesis (MAS) technology uses digital light processing and rapid, high-yield photochemistry to synthesize long oligo, high-density DNA microarrays with extreme flexibility. Each GPL8093 chip measures the expression level of 18155 genes from Phytophthora infestans with 60-mer probe pairs (PM/MM) per gene. Total RNA samples recovered from mycelia in two medias (rye sucrose agar and V8 agar) and infected potato leaves from a time couse infection (2, 3 and 4 days post incoulation). Experiments included two biological repllicates from each sample. We carried out total RNA extractions (mycelia and potato infected material) for two P. infestans isolates 06_3928A and NL07434. cDNA synthesis was performed Nimblegen.
Project description:The late blight pathogen, Phytophthora infestans has a broad host range within the Solanaceae family, including yellow potato (Solanum phureja). The disease caused by P. infestans in S. phureja is poorly understood and is a major concern in Colombia. Expressed Sequence Tag (EST) libraries obtained from a normalized library constructed from healthy plant tissue revealed high levels of sequence similarity between S. phureja and S. tuberosum. Then, utilizing Serial Analysis of Gene Expression and high-throughput sequencing (SAGE-Solexa), we characterized yellow potato gene expression during infection by P. infestans. Four-week-old yellow potato plants were inoculated with P. infestans and were collected at 12 and 72 hours post inoculation for RNA extraction. We detected differentially expressed genes by comparing inoculated to non-inoculated and resistant to susceptible plants. The discovery and characterization of the proteins mediating this host–pathogen interaction enable the understanding of the pathosystem and is the key for developing resistant plants. Keywords: SAGE-Solexa, inoculation response, transcript profiling, Solanum phureja, Phytophthora infestans
Project description:Lima bean is an important vegetable processing crop to the Mid-Atlantic U.S. and is highly susceptible to the oomycete pathogen Phytophthora phaseoli, which causes downy mildew. P. phaseoli resides in the same clade with the late blight pathogen, Phytophthora infestans. Genetic resistance and fungicides are used to manage P. phaseoli and often fail. Currently there are no molecular data on this pathosystem. To rectify this situation and determine virulence mechanisms in P. phaseoli we performed a whole-transcriptome analysis using Illumina mRNA-Seq. Six libraries were generated and compared, plate-grown and plant-grown. Our data were normalized and were matched to the P. infestans gene models to obtain the abundance of the sequence reads. This resulted in 10,427 P. phaseoli genes with homology to P. infestans and with expression in either one of the libraries. Upon closer examination, 318 P. phaseoli-homologs matched either known or putative virulence genes in P. infestans. We present data from the whole transcriptome as well as specifically chosen genes from this set of 318. Interestingly, in six libraries from P. phaseoli we found a commonly expressed gene set of 66 out of 563 predicted RXLR genes in P. infestans. The majority of the differentially expressed RxLR and elicitin-like were up-regulated in planta, while the reverse was true for crinkler homologs. These results are discussed with respect to possible pathogenicity mechanisms in P. phaseoli and how they compare to P. infestans. Examination of 3 different conditions of Phytophthora phaseoli
Project description:Filamentous (oomycete and fungal) plant pathogens can deliver cytoplasmic effector proteins into host cells to facilitate disease. How RXLR effectors from the potato late blight pathogen Phytophthora infestans enter host cells is unknown. One possible route involves clathrin-mediated endocytosis (CME). Transient silencing of NbCHC, encoding clathrin heavy chain, or endosome marker NbAra6 in the model host Nicotiana benthamiana, attenuated P. infestans infection and reduced translocation of RXLR effector fusions from transgenic pathogen lines into host cells. In contrast, silencing PP1c isoforms, susceptibility factors that are not required for endocytosis, reduced infection but did not attenuate RXLR effector uptake. Endosome enrichment by ultracentrifugation and sucrose gradient fractionation revealed co-localisation of RXLR effector Pi04314-RFP with clathrin-coated vesicles. Immunopurification of clathrin- and NbAra6-associated vesicles during infection revealed that RXLR effectors Pi04314-RFP and AvrBlb1-RFP, but not apoplastic effector PiSCR74-RFP, were co-immunoprecipitated during infection with pathogen lines secreting these effectors. MS/MS analyses of proteins co-immunoprecipitated with NbAra6-GFP during infection revealed enrichment of host proteins associated with endocytic vesicles alongside multiple pathogen RXLR effectors, but not apoplastic effectors, including PiSCR74, which do not enter host cells. Our data show that uptake of P. infestans RXLR effectors into plant cells occurs via CME.