Project description:In this study, we performed a large-scale leaf phosphoproteomic analysis of two wheat genotypes HX10 and NC47 to explore the complex protein phosphorylation network of signaling and regulatory events affecting rapid vegetative growth in wheat. We used TiO2 affinity chromatography combined with LC-MS/MS and Maxquant software to identify phosphopeptides and phosphorylated sites. Finally, 2,336 phosphopeptides containing 2,734 phosphorylation sites were identified from the two wheat genotypes HX10 and NC47 in our study.
Project description:Mycosphaerella graminicola is the causal agent of Mycosphaerella graminicola infection (STB) disease of wheat. Wheat genotypes vary in their response to this disease. Cultivar (cv.) Longbow is susceptible and cv. Flame is resistant to STB disease, with cv. Flame possessing the STB resistance locus Stb6 that confers resistance to pathogen strain IPO323. Gene expression profiling (conducted using Affymetrix wheat gene chip) identified transcripts that accumulate in leaves of both these wheat cultivars as an early response to M. graminicola strain IPO323 (at 24h post-treatment). At this initial time point, microscopic analysis verified that fungal spores had germinated, but not penetrated the leaves of both genotypes. Results showed that basal defence genes were activated in both the compatible and incompatible interactions. A subset of genes were identified that were more pathogen-responsive in the cv. Flame v. IPO323 incompatible interaction as compared to the cv. Longbow v. IPO323 compatible interaction, including defence genes such as peroxidases, beta-1,3-glucanase, annexin, chitinases, brassinosteroid-associated kinase 1 and a jasmonate-inducible protein.
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:We undertook a time course analysis of gene expression between mock (non)-inoculated and pathogen (Puccinia triticinia)-infected wheat samples using RNA sequencing (RNA-Seq).
Project description:The RNA sequencing analysis was undertaken to investigate the transcriptomic changes in adult wheat inoculated with Puccinia graminis f. sp. tritici the causal agent of stem rust disease. The project firstly aims to compare gene expression in one susceptible wheat line with two wheat lines exhibiting adult plant resistance to the stem rust. Secondly, the project aims to examine the temporal changes in gene expression in wheat after inoculation. Wheat plants was grown until maturity under greenhouse conditions. Plants were inoculated with Puccinia graminis f. sp. tritici and the flag leaf sheath sampled for RNA sequencing. The project aims to give essential insight into the adult plant resistance response in wheat to Puccinia graminis f. sp. tritici inoculation.
Project description:Recent attempts to increase endogenous disease resistance of plants by overexpression of anti-fungal transgenes have shown a potential of this method. However, it has also been shown that such improvements are usually small. One of the obvious reasons for this low anti-fungal effect might be the regulation of endogenous genes in parallel. In this project, we will study the effect of anti-fungal transgenes on the endogenous gene expression. Such effects might relate to substantial equivalence which is a biosafety issue of concern to the public. The GeneChip Wheat Genome Array will be used to detect expression of defence response genes and key genes of metabolic pathways. We will use wheat plants transformed with anti-fungal gene of specific effect against a small group of seed transmitted, pathogenic fungi (KP4 against smuts and bunts). Transformed spring wheat line will be challenged by stinking smut (inhibited by KP4). The effect on the endogenous gene expression will be tested for plants grown in the field in collaboration with the USDA Department. This work will contribute to our understanding of plant defence responses in general and may allow improving strategies to strengthen these responses. Teliospores of pathogenic races T-1, T-5 and T-16 of T. caries provided by a collection in Aberdeen, ID, USA were used for the tests. Seeds of the genetically engineered Swiss spring wheat variety Greina (GrKP4) and the null-segregant control line (Gr0) were coated with spores and Individual plants were scored for bunt symptoms. For microarray analysis only samples inoculated with T1 and T16 were used.
Project description:This study was aimed at deciphering the impact of drought and heat on genome-wide gene expression in flag leaf of barley. We employed high-throughput sequencing of mRNA to identify genes that are associated with response to drought or heat and to their combination. Our study demonstrated that under combined stress, drought was the dominant factor affecting genes expression. It was also confirmed for phenotypic traits and chlorophyll fluorescence parameters. Drought- and heat-responsive genes were associated majorly with photosynthesis, abscisic acid signaling and lipids transport. Dehydrin encoding genes were found to be universal stress-responsive genes. Stress-induced genes specific to the flag leaf size were also found. This research provided novel insight into molecular mechanisms of barley flag leaf that determine drought and heat response, also during their co-occurrence.
Project description:A global, systems-based study of the transcriptome response of three drought resistant durum wheat genotypes to water stress. Two parents of a mapping population (Lahn x Cham 1) and a recombinant inbred line (RIL2219), selected for their drought resistance in multiyear field trials, were subjected to controlled time series water stress and samples taken over a six day period to study flag leaf gene expression in parallel with physiological measurements. The aim was to dissect the responses to water stress in an attempt to identify molecular and physiological properties defining stress resistance and thus to build knowledge to accelerate the breeding effort.
Project description:To identify genes involved in susceptibility, genechip hybridization experiments were performed in order to examine genes differentially expressed upon inoculation of resistant and susceptible wheat cultivars with powdery mildew. Some genes were identified which were just expressed in the susceptible host both after mock-inoculation and pathogen infection. Also, a total of 2693 transcripts were differentially expressed (fold change≥2) in Yumai 13 in response to powdery mildew as compared to itself, comprising 1464 and 1229 up- and down-regulated genes respectively. Seven-day-old wheat seedlings of susceptible cultivar Yumai 13, two resistant cultivars HY and CYC were inoculated with powdery mildew and harvested at 0, 24, 48 hpi for RNA extraction and hybridization on Affymetrix microarrays. We sought to screen some genes which have very high expression in Yumai 13, but not in CYC and HY by pairwise comparation.
Project description:The closely related Coffea arabica cultivars ‘Tall Mokka’ and ‘Typica’, with excellent flavor, but differing distinctively in the size of aerial organs, branching pattern and branch numbers. Differential gene expression analysis of shoot tips of arabica coffee cultivars 'Tall Mokka' and 'Typica' were done using Potato cDNA microarray as cross-species platform. Using cross-species microarray hybridization, we identified a prolyl oligopeptidase (CaPOP) gene as differentially expressed between the shoot tips of ‘Tall Mokka’ and ‘Typica’. Isolation and sequencing of POP genes from coffee identified three paralogs, CaPOP1, CaPOP2 and CaPOP3. All three genes were present in both cultivars, which suggest that differences in the expression of CaPOP are caused by factor(s) regulating the transcription of CaPOPs. CaPOP1 differs in sequence from CaPOP2 primarily in having two large deletions in the promoter region. CaPOP genes are homologous to arabidopsis At1g20380, encoding a post-proline cleaving enzyme that acts on substrates shorter than 30 amino acids. Ectopic expression of CaPOP1 under its native promoter in transgenic arabidopsis resulted in more secondary branches than in the wild type. This is the first study to successfully isolate CaPOP genes and characterize their expression in the developing tissues of coffee. This study also identified a novel role for prolyl oligopeptidase in control of branching. Eight coffee trees of 'Typica' ('K') and six trees of 'Tall Mokka' ('M') cultivar were used in this study. The trees were equally divided into two groups 'A' and 'B' for each cultivar ('MA','MB', 'KA' and 'KB') and treated as biological replicates. Eight two channel microarray hybridizations were done in following pairs: MA x KA, MA x KB, MB x KA, MB x KB and dye swap replicate of each pair. Summary: Two-sample experiment: Tall Mokka vs. Typica . 8 Hybridizations. 2 Biological replicates per sample. 1 Dye swap per array.