Project description:Arabidopsis is a non-host to the biotrophic fungus Blumeria graminis f.sp. hordei (Bgh), effectively hindering Bgh ingress to the epidermal cells by deposition of callosic papillae formations, i.e. penetration resistance. To better understand the transcriptional changes in Arabidopsis towards Bgh, we compared un-inoculated and inoculated wild-type Arabidopsis samples, with those an ATAF1 mutant allele, compromised in penetration resistance. The experiment included sampling of 8 rosettes for each replicate sample from 6-weeks old plants, 12 hrs after inoculation. A total of 12 biolocigal replicates were sampled with three replicates from each of the four blocks (Wild-type, ataf1-1, Bgh, control). ****[PLEXdb(http://www.plexdb.org) has submitted this series at GEO on behalf of the original contributor, Michael Krogh Jensen. The equivalent experiment is AT31 at PLEXdb.] Experiment Overall Design: genotype: Wild-type Arabidopsis, ecotype Col-0 - treated or untreated: Un-inoculated(3-replications); genotype: Wild-type Arabidopsis, ecotype Col-0 - treated or untreated: Bgh inoculated(3-replications); genotype: ataf1-1 mutant, ecotype Col-0 - treated or untreated: Un-inoculated(3-replications); genotype: ataf1-1 mutant, ecotype Col-0 - treated or untreated: Bgh inoculated(3-replications)
Project description:Arabidopsis is a non-host to the biotrophic fungus Blumeria graminis f.sp. hordei (Bgh), effectively hindering Bgh ingress to the epidermal cells by deposition of callosic papillae formations, i.e. penetration resistance. To better understand the transcriptional changes in Arabidopsis towards Bgh, we compared un-inoculated and inoculated wild-type Arabidopsis samples, with those an ATAF1 mutant allele, compromised in penetration resistance. The experiment included sampling of 8 rosettes for each replicate sample from 6-weeks old plants, 12 hrs after inoculation. A total of 12 biolocigal replicates were sampled with three replicates from each of the four blocks (Wild-type, ataf1-1, Bgh, control). ****[PLEXdb(http://www.plexdb.org) has submitted this series at GEO on behalf of the original contributor, Michael Krogh Jensen. The equivalent experiment is AT31 at PLEXdb.]
Project description:A split-split-plot design with 144 experimental units (3 replications x 4 genotypes x 6 time points x 2 treatment types) was used to profile barley plants containing variants of Mla1 and Mla6 powdery mildew resistance genes in response to inoculation with the Blumeria graminis f. sp. hordei (Bgh) isolates 5874 (AvrMla1, AvrMla6). Barley leaves were harvested from inoculated and non-inoculated plants at 6 time points (0,8,16,20,24 and 32 hrs) after Bgh inoculation. ****[PLEXdb(http://www.plexdb.org) has submitted this series at GEO on behalf of the original contributor, Rico Caldo. The equivalent experiment is BB10 at PLEXdb.]
Project description:Colonization of barley roots with the basidiomycete fungus Piriformospora indica enhances resistance against the leaf pathogen Blumeria graminis f.sp. hordei (Bgh). To identify genes involved in this mycorrhiza-induced systemic resistance, we used the Affymetrix Barley1 22K gene chip for leaf transcriptome analysis of P. indica-colonized and non-colonized barley plants 12, 24 and 96 hours post inoculation (hpi) with a compatible Bgh strain.
Project description:Time-course expression profiles of Bgh challenged barley cultivar C.I. 16151 (harboring the Mla6 powdery mildew resistance allele) and its fast-neutron-derived "Bgh-induced tip cell death1" mutant, bcd1, were compared using the 22K Barley1 GeneChip. Planting, stage of seedlings, harvesting, and experimental design were part of a larger experiment described by Caldo et al. (2004). PLEXdb BB4. Experiment Design: C.I. 16151 (wildtype) and bcd1 (mutant) were planted in separate 20 x 30-cm flats using sterilized potting soil. Each experimental flat consisted of six rows of 15 seedlings, with rows randomly assigned to one of six harvest time points (0, 8, 16, 20, 24, and 32 hai). Seedlings grown to the 1st leaf stage with 2nd leaf unfolded were inoculated with a high density of fresh conidiospores (84 +/- 19 spores/mm2). Groups of flats were placed at 18C (8-hour darkness, 16-hour light) in separate controlled growth chambers corresponding to the Bgh isolates. Rows of plants were harvested at each assigned time points and snap frozen in liquid nitrogen. The entire experiment was repeated three times in a standard split-split-plot design with 72 experimental units (2 genotypes x 2 pathogen isolates x 6 time points x 3 replications). Treatment Description: The samples constituted pairwise combinations of the the cultivar C.I. 16151(containing the Mla6 resistance allele), and its fast-neutron-derived "Bgh-induced tip cell death1" mutant, bcd1 with the two Bgh (Blumeria graminis f. sp. hordei) isolates, 5874 (AvrMla6, AvrMla1) and K1 (AvrMla13, AvrMla1). For each replication, individual genotypes were planted in separate 20 x 30 cm flats using sterilized potting soil. Each experimental flat consisted of six rows of 15 seedlings, with rows randomly assigned to one of six harvest times (0, 8, 16, 20, 24, and 32 hai). Seedlings were grown to the 2nd-leaf stage with 1st leaf unfolded, and inoculation was performed at 4 PM Central Standard Time by tipping the flats at 45oC and dusting the plants with a high density of fresh conidiospores [84 +/- 19 spores/mm2]. This procedure was repeated from the opposite angle to ensure that a high proportion of the cells are in contact with the fungus. This conidial density per unit leaf area routinely results in greater than 50% of epidermal cells that are successfully infected. Groups of flats were placed at 18oC (8 hours darkness, 16 hours light, 8 hours darkness) in separate controlled growth chambers corresponding to the Bgh isolate. Rows of plants were harvested at their assigned harvest times and flash-frozen in liquid nitrogen. ****[PLEXdb(http://www.plexdb.org) has submitted this series at GEO on behalf of the original contributor, Roger P Wise. The equivalent experiment is BB46 at PLEXdb.]
Project description:Attack by the host powdery mildew Erysiphe cichoracearum usually results in successful penetration and rapid proliferation of the fungus on Arabidopsis. By contrast, the nonhost barley powdery mildew Blumeria graminis f. sp. hordei (Bgh) typically fails to penetrate Arabidopsis epidermal cells. In both instances the plant secretes cell wall appositions or papillae beneath the penetration peg of the fungus. Genetic screens for mutations that result in increased penetration of Bgh on Arabidopsis have recently identified the PEN1 syntaxin. Here we examine the role of PEN1 and of its closest homologue, SYP122, identified as a syntaxin whose expression is responsive to infection. pen1 syp122 double mutants are both dwarfed and necrotic, suggesting that the two syntaxins have overlapping functions. Although syp122-1 and the cell wall mur mutants have considerably more pronounced primary cell wall defects than pen1 mutants, these have relatively subtle or no effects on penetration resistance. Upon fungal attack, PEN1 appears to be actively recruited to papillae, and there is a 2-h delay in papillae formation in the pen1-1 mutant. We conclude that SYP122 may have a general function in secretion, including a role in cell wall deposition. By contrast, PEN1 appears to have a basal function in secretion and a specialized defense-related function, being required for the polarized secretion events that give rise to papilla formation.
Project description:RNA-seq experiments detected fungal expression patterns during infection of immunocompromised Arabidopsis thaliana 3 biological replicates per condition. Arabidopsis plants without (pps) or with (B12) the MLA1-HA construct in pen2 pad4 sag101 background were challenged with either Bgh isolate K1 expressing the cognate AVRA1 effector for MLA1 or Bgh isolate A6 expressing other AVRA effectors. Samples were collected at 6, 12, 18, 24 hours post inoculation (hpi) of Bgh.
Project description:Powdery 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. To describe rice gene expression profiles during nonhost interaction, 2 week-old rice plantlets were inoculated with Bgh. Treated (inoculated) and control (mock) samples were collected 24 hours post-inoculation for GeneChip® Rice Genome Array hybridization.
Project description:A large-scale parallel expression analysis was conducted to elucidate Mla-specified responses to powdery mildew infection using 22K Barley1 GeneChip probe arrays. Our goal was to identify genes differentially expressed in incompatible (resistant) vs. compatible (susceptible) and Mla-specified Rar1-dependent vs. -independent interactions. A split-split-plot design with 108 experimental units (3 replications x 2 isolates x 3 genotypes x 6 time points) was used to profile near-isogenic lines containing the Mla1, Mla6, and Mla13 resistance specificities in response to inoculation with the Blumeria graminis f. sp. hordei (Bgh) isolates 5874 (AvrMla1, AvrMla6) and K1 (AvrMla1, AvrMla13).
Project description:Arabidopsis is a host to the fungal powdery mildew pathogen, Erysiphe cichoracearum, and a nonhost to Blumeria graminis f.sp. hordei, the powdery mildew pathogenic on barley. A screen for mutants that allowed increased entry by this inappropriate or nonhost pathogen on Arabidopsis led to the identification of PEN3. While pen3 mutants permitted both increased penetration and increased hyphal growth by B. g. hordei, they were unexpectedly resistant to E. cichoracearum. This resistance was correlated with the appearance of chlorotic patches and was salicylic acid-dependent. Consistent with this observation, microarray analysis revealed that the salicylic acid defense pathway was hyper-induced in pen3 relative to wild type following inoculation with either E. cichoracearum or B. g. hordei. The pen3 phenotypes result from a loss of function of AtPDR8, a ubiquitously and highly expressed ATP binding cassette transporter. PEN3 protein tagged with green fluorescent protein localized to the plasma membrane in uninfected cells. In infected leaves, the protein concentrated to high levels at infection sites and surrounded fungal penetration pegs. We hypothesize that PEN3 may be involved in exporting toxic substrates to sites of infection and that accumulation of these substrates intracellularly in the pen3 mutant may secondarily activate the salicylic acid pathway. Experiment Overall Design: Three week-old wild-type Col and mutant pen3 Arabidopsis thaliana plants were inoculated with Erysiphe cichoracearum, Blumeria graminis hordei, or not inoculated. 1 day post inoculation 16 rosettes were harvested per replicate. 4 replicates were perfomerd per treatment.