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Temporal gene expression profiling of the wheat leaf rust pathosystem using cDNA microarray reveals differences in compatible and incompatible defence pathways.

ABSTRACT: In this study, we detail the construction of a custom cDNA spotted microarray containing 7728 wheat ESTs and the use of the array to identify host genes that are differentially expressed upon challenges with leaf rust fungal pathogens. Wheat cultivar RL6003 (Thatcher Lr1) was inoculated with Puccinia triticina virulence phenotypes BBB (incompatible) or TJB (7-2) (compatible) and sampled at four different time points (3, 6, 12, and 24 hours) after inoculation. Transcript expression levels relative to a mock treatment were measured. One hundred ninety two genes were found to have significantly altered expression between the compatible and incompatible reactions. Among those were genes involved in photosynthesis, the production of reactive oxygen species, ubiquitination, signal transduction, as well as in the shikimate/phenylpropanoid pathway. These data indicate that various metabolic pathways are affected, some of which might be used by RL6003 to mount a coordinated defense against an incompatible fungal pathogen.

SUBMITTER: Fofana B

PROVIDER: S-EPMC2216066 | biostudies-literature | 2007

REPOSITORIES: biostudies-literature

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Temporal gene expression profiling of the wheat leaf rust pathosystem using cDNA microarray reveals differences in compatible and incompatible defence pathways.

Fofana Bourlaye B Banks Travis W TW McCallum Brent B Strelkov Stephen E SE Cloutier Sylvie S

International journal of plant genomics 20070101

In this study, we detail the construction of a custom cDNA spotted microarray containing 7728 wheat ESTs and the use of the array to identify host genes that are differentially expressed upon challenges with leaf rust fungal pathogens. Wheat cultivar RL6003 (Thatcher Lr1) was inoculated with Puccinia triticina virulence phenotypes BBB (incompatible) or TJB (7-2) (compatible) and sampled at four different time points (3, 6, 12, and 24 hours) after inoculation. Transcript expression levels relativ ...[more]

PMID: 18288238

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Project description:Wheat leaf rust caused by the pathogenic fungus Puccinia triticina, is a serious threat to bread wheat and durum production in many areas of the world. This plant-pathogen interaction has been studied extensively at the molecular genetics level, however proteomics data are still relatively scarce. The present study investigated temporal changes in the abundance of the apoplastic fluid proteome of wheat leaves infected with either virulent or avirulent races of P. triticina, using a label-free LC-MS-based approach. In general, there was very little difference between inoculated and control apoplastic proteomes as a result of either race of pathogen, until haustoria had become well established in the incompatible interaction, although the resistant host responds to pathogen challenge sooner than the susceptible. In the earlier samplings (up to 72 h after inoculation), there were 46 host proteins with significantly changing abundance, however pathogen proteins were detected only rarely and not reproducibly. This is consistent with the hemi-biotrophic life-style of P. triticina; the pathogen infection is characterized by an early phase of a symbiosis-like relationship, followed by a later stage of pathogenesis, with tissue damage and parasitism. The majority of the host proteins with altered abundance up to 72 h post-inoculation were pathogen-response-related, including peroxidases, chitinases, β-1-3-endo-glucanases and PR-proteins. Five days after inoculation with the incompatible race it was possible to detect 150 PT proteins and 117 host proteins which had significantly increased in abundance as well as 33 host proteins which had significantly decreased in abundance and which represent potential targets of pathogen effectors. The pathogen-expressed proteins – seen most abundantly in the incompatible interaction – were mostly uncharacterized proteins, however many of their functions could be inferred through homology-matching with pBLAST. Pathogen proteins also included several candidate effector proteins, some novel and some which have been reported previously from the purified haustoria proteome.

Project description:BackgroundStripe rust of wheat, caused by Puccinia striiformis f. sp. tritici (Pst), is one of the most important diseases of wheat worldwide. Due to special features of hexaploid wheat with large and complex genome and difficulties for transformation, and of Pst without sexual reproduction and hard to culture on media, the use of most genetic and molecular techniques in studying genes involved in the wheat-Pst interactions has been largely limited. The objective of this study was to identify transcriptionally regulated genes during an incompatible interaction between wheat and Pst using cDNA-AFLP techniqueResultsA total of 52,992 transcript derived fragments (TDFs) were generated with 64 primer pairs and 2,437 (4.6%) of them displayed altered expression patterns after inoculation with 1,787 up-regulated and 650 down-regulated. We obtained reliable sequences (>100 bp) for 255 selected TDFs, of which 113 (44.3%) had putative functions identified. A large group (17.6%) of these genes shared high homology with genes involved in metabolism and photosynthesis; 13.8% to genes with functions related to disease defense and signal transduction; and those in the remaining groups (12.9%) to genes involved in transcription, transport processes, protein metabolism, and cell structure, respectively. Through comparing TDFs identified in the present study for incompatible interaction and those identified in the previous study for compatible interactions, 161 TDFs were shared by both interactions, 94 were expressed specifically in the incompatible interaction, of which the specificity of 43 selected transcripts were determined using quantitative real-time polymerase chain reaction (qRT-PCR). Based on the analyses of homology to genes known to play a role in defense, signal transduction and protein metabolism, 20 TDFs were chosen and their expression patterns revealed by the cDNA-AFLP technique were confirmed using the qRT-PCR analysis.ConclusionWe uncovered a number of new candidate genes possibly involved in the interactions of wheat and Pst, of which 11 TDFs expressed specifically in the incompatible interaction. Resistance to stripe rust in wheat cv. Suwon11 is executed after penetration has occurred. Moreover, we also found that plant responses in compatible and incompatible interactions are qualitatively similar but quantitatively different soon after stripe rust fungus infection.

Project description:Leaf rust caused by Puccinia triticina (Pt) is one of the most important diseases of bread wheat globally. Recent advances in sequencing technologies have provided opportunities to analyse the complete transcriptomes of the host as well as pathogen for studying differential gene expression during infection. Pathogen induced differential gene expression was characterized in a near isogenic line carrying leaf rust resistance gene Lr57 and susceptible recipient genotype WL711. RNA samples were collected at five different time points 0, 12, 24, 48, and 72 h post inoculation (HPI) with Pt 77-5. A total of 3020 transcripts were differentially expressed with 1458 and 2692 transcripts in WL711 and WL711+Lr57, respectively. The highest number of differentially expressed transcripts was detected at 12 HPI. Functional categorization using Blast2GO classified the genes into biological processes, molecular function and cellular components. WL711+Lr57 showed much higher number of differentially expressed nucleotide binding and leucine rich repeat genes and expressed more protein kinases and pathogenesis related proteins such as chitinases, glucanases and other PR proteins as compared to susceptible genotype. Pathway annotation with KEGG categorized genes into 13 major classes with carbohydrate metabolism being the most prominent followed by amino acid, secondary metabolites, and nucleotide metabolism. Gene co-expression network analysis identified four and eight clusters of highly correlated genes in WL711 and WL711+Lr57, respectively. Comparative analysis of the differentially expressed transcripts led to the identification of some transcripts which were specifically expressed only in WL711+Lr57. It was apparent from the whole transcriptome sequencing that the resistance gene Lr57 directed the expression of different genes involved in building the resistance response in the host to combat invading pathogen. The RNAseq data and differentially expressed transcripts identified in present study is a genomic resource which can be used for further studying the host pathogen interaction for Lr57 and wheat transcriptome in general.

Project description:BACKGROUND: Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is one of the most destructive diseases of wheat worldwide. To establish compatibility with the host, Pst forms special infection structures to invade the plant with minimal damage to host cells. Although compatible interaction between wheat and Pst has been studied using various approaches, research on molecular mechanisms of the interaction is limited. The aim of this study was to develop an EST database of wheat infected by Pst in order to determine transcription profiles of genes involved in compatible wheat-Pst interaction. RESULTS: Total RNA, extracted from susceptible infected wheat leaves harvested at 3, 5 and 8 days post inoculation (dpi), was used to create a cDNA library, from which 5,793 ESTs with high quality were obtained and clustered into 583 contigs and 2,160 singletons to give a set of 2,743 unisequences (GenBank accessions: GR302385 to GR305127). The BLASTx program was used to search for homologous genes of the unisequences in the GenBank non-redundant protein database. Of the 2,743 unisequences, 52.8% (the largest category) were highly homologous to plant genes; 16.3% to fungal genes and 30% of no-hit. The functional classification of all ESTs was established based on the database entry giving the best E-value using the Bevan's classification categories. About 50% of the ESTs were significantly homologous to genes encoding proteins with known functions; 20% were similar to genes encoding proteins with unknown functions and 30% did not have significant homology to any sequence in the database. The quantitative real-time PCR (qRT-PCR) analysis determined the transcription profiles and their involvement in the wheat-Pst interaction for seven of the gene. CONCLUSION: The cDNA library is useful for identifying the functional genes involved in the wheat-Pst compatible interaction, and established a new database for studying Pst pathogenesis genes and wheat defense genes. The transcription patterns of seven genes were confirmed by the qRT-PCR assay to be differentially expressed in wheat-Pst compatible and incompatible interaction.

Project description:Wheat leaf rust caused by the pathogenic fungus, Puccinia triticina, is a serious threat to bread wheat and durum production in many areas of the world. This plant-pathogen interaction has been studied extensively at the molecular genetics level however, proteomics data are still relatively scarce. The present study investigated temporal changes in the abundance of the apoplastic fluid proteome of resistant and susceptible wheat leaves infected with P. triticina race-1, using a label-free LC-MS-based approach. In general, there was very little difference between inoculated and control apoplastic proteomes in either host, until haustoria had become well established in the susceptible host, although the resistant host responds to pathogen challenge sooner. In the earlier samplings (up to 72 h after inoculation) there were just 46 host proteins with significantly changing abundance, and pathogen proteins were detected only rarely and not reproducibly. This is consistent with the biotrophic lifestyle of P. triticina, where the invading pathogen initially causes little tissue damage or host cell death, which occur only later during the infection cycle. The majority of the host proteins with altered abundance up to 72 h post-inoculation were pathogen-response-related, including peroxidases, chitinases, ?-1-3-endo-glucanases, and other PR proteins. Five days after inoculation with the susceptible apoplasm it was possible to detect 150 P. triticina proteins and 117 host proteins which had significantly increased in abundance as well as 33 host proteins which had significantly decreased in abundance. The latter represents potential targets of pathogen effectors and included enzymes which could damage the invader. The pathogen-expressed proteins-seen most abundantly in the incompatible interaction-were mostly uncharacterized proteins however, many of their functions could be inferred through homology-matching with pBLAST. Pathogen proteins also included several candidate effector proteins, some novel, and some which have been reported previously. All MS data have been deposited in the PRIDE archive (www.ebi.ac.uk/pride/archive/) under Project PXD012586.

Project description:Transcriptional changes were monitored in the wheat cultivar Avocet*6/Yr1 following inoculation with avirulent and virulent wheat yellow rust (Puccinia striiformis f.sp. tritici) isolates using the Affymetrix wheat genome array GeneChip®. Seedlings of Avocet*6/Yr1 were grown to growth stage 12-13 (Zadoks et al., 1974) before inoculating with either the P.s. f.sp. tritici isolate 169E136 (Yr1-virulent) or 232E137 (Yr1-avirulent) or with talc for the Mock inoculation (Boyd and Minchin 2001). Plants were grown under a 16/8 hour photoperiod cycle, supplemented with sodium lighting (240 ?mol m-2 s-1) at day/night temperatures of 20°C/15°C and a relative humidity of 60%, both before and after inoculation, in a spore-free, containment level 2 greenhouse. Leaf samples from six seedlings were collected 6, 12, 24, 48 and 72 hpi for RNA extraction and transcriptomics analysis from three independent biological experiments. Leaf tissue was ground under liquid nitrogen and total RNA extracted using the TRIzol reagent method, following the manufacturer’s instructions (Invitrogen, Carlsbad, CA). RNA from each time point (16 ?g) were pooled to obtain 80 ?g of total RNA for each treatment (mock inoculated control; avirulent isolate inoculated; virulent isolate inoculated). Pooled RNA samples were further purified using the Qiagen RNeasy mini-kit according to the manufacturer instructions (Qiagen) and RNA integrity was confirmed using the Agilent 2100 Bioanalyzer (Agilent). Affymetrix GeneChip processing, including RNA quality control, microarray hybridisation and data acquisition was performed through contract research services by the John Innes Genome Laboratory, John Innes Centre, Norwich, U.K. A total of nine hybridisations were performed. ****[PLEXdb(http://www.plexdb.org) has submitted this series at GEO on behalf of the original contributor, Osman Bozkurt. The equivalent experiment is TA25 at PLEXdb.] pathogen isolates: Mock inoculated (Control)(3-replications); pathogen isolates: Yr1-avirulent wheat yellow rust isolate 232E137(3-replications); pathogen isolates: Yr1-virulent wheat yellow rust isolate 169E136(3-replications)

Dataset Information

Temporal gene expression profiling of the wheat leaf rust pathosystem using cDNA microarray reveals differences in compatible and incompatible defence pathways.

Publications

Temporal gene expression profiling of the wheat leaf rust pathosystem using cDNA microarray reveals differences in compatible and incompatible defence pathways.

Similar Datasets

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