Project description:In the present study molecular interactions between potato plants, Colorado potato beetle (CPB) larvae and Potato virus YNTN (PVYNTN) were investigated by analyzing gene expression in potato leaves. mRNA samples of secondary PVYNTN-infected (CPB_PVY) and healthy potato plants (CPB_H) cultivar Igor and of RNAi coi1-silenced (CPB_coi1) and non-transformed (CPB_NT) potato plants cultivar Desiree collected 24 h post CPB infestation and respective control non-infested samples (CONT_PVY, CONT_H, CONT_coi1, CONT_NT).
Project description:Potato Late blight is one the most important crop diseases worldwide. Even though potato has been studied for many years, the potato disease late blight still has a huge negative effect on the potato production. A total of three commercially available field potato cultivars of different resistance to late blight infection: Kuras (moderate), Sarpo Mira (highly resistant) and Bintje (very suseptable) under controlled green house growing conditions innoculated with a diversity of P. infestans populations. We used label-free quantitative proteomics to investigate the infection with P. infestans in a time-course study over 258 hours. Several key issues limits proteome analysis of potato leaf tissue4–6. Firstly, the immense complexity of the plant proteome which is further complicated by the presence of highly abundant proteins, such as ribulose bisphosphate carboxylase/oxygenase (RuBisCO). Secondly, plant leaf and potato in particular contain abundant levels amounts of phenols and polyphenols which hinder or, unless precautions are taken, completely prevent a successful protein extraction.
Project description:Purpose: MicroRNAs (miRNAs) are ubiquitous components of endogenous plant transcriptome. miRNAs are small, single-stranded and ~21 nt long RNAs which regulate gene expression at the post-transcriptional level and are known to play essential roles in various aspects of plant development and growth. Previously, a number of miRNAs have been identified in potato through in silico analysis and deep sequencing approach. However, identification of miRNAs through deep sequencing approach was limited to a few tissue types and developmental stages. This study reports the identification and characterization of potato miRNAs in three different vegetative tissues and four stages of tuber development by high throughput sequencing. Results: Small RNA libraries were constructed from leaf, stem, root and four early developmental stages of tuberization and subjected to deep sequencing, followed by bioinformatics analysis. A total of 89 conserved miRNAs (belonging to 33 families), 147 potato-specific miRNAs (with star sequence) and 112 candidate potato-specific miRNAs (without star sequence) were identified. The digital expression profiling based on TPM (Transcripts Per Million) and qRT-PCR analysis of conserved and potato-specific miRNAs revealed that some of the miRNAs showed tissue specific expression (leaf, stem and root) while a few demonstrated tuberization stage-specific expressions. Targets were predicted for identified conserved and potato-specific miRNAs, and predicted targets of four conserved miRNAs, miR160, miR164, miR172 and miR171, which are ARF16 (Auxin Response Factor 16), NAM (NO APICAL MERISTEM), RAP1 (Relative to APETALA2 1) and HAIRY MERISTEM (HAM) respectively, were experimentally validated using 5M-bM-^@M-2RLM-RACE (RNA ligase mediated rapid amplification of cDNA ends). Gene ontology (GO) analysis for potato-specific miRNAs was also performed to predict their potential biological functions. Conclusions: We report a comprehensive study of potato miRNAs at genome-wide level by high-throughput sequencing and demonstrate that these miRNAs have tissue and/or developmental stage specific expression profile. Also, predicted targets of conserved miRNAs were experimentally confirmed for the first time in potato. Our findings indicate the existence of extensive and complex small RNA population in this crop and suggest their important role in pathways involved in diverse biological processes, including tuber developmental process. Total seven (Leaf, Root, Stem, Potato Tuber stage 0(PT0),Potato Tuber stage 1(PT1),Potato Tuber stage 2(PT2),Potato Tuber stage 3(PT3) ) small RNA libraries were consctructed and sequenced by deep sequencing using Illumina GAIIx.
Project description:Chloroplast, the energy organelle unique to plants and green algae, performs a wide range of functions including photosynthesis and biosynthesis of metabolites. However, as the most important tuber crop worldwide, the potato (Solanum tuberosum) chloroplast proteome has not been explored. Here, we use Percoll density gradient centrifugation to isolate intact chloroplasts from leaves of potato cultivar E3 and establish a reference proteome map of potato chloroplast by bottom-up proteomics. A total of 1834 non-redundant proteins, including 51 proteins encoded by the chloroplast genome, were identified in the chloroplast proteome. Extensive sequence-based localization prediction revealed over 62% of proteins to be chloroplast resident by at least one algorithm. A total of 16 proteins were selected for evaluating the prediction result by transient fluorescence assay and confirmed that 14 of them were distributed on distinct internal compartments of the chloroplast. In addition, 136 phosphorylation sites were identified in 61 proteins encoded by chloroplast proteome. Furthermore, by a comparative analysis between chloroplast and previously reported amyloplast proteomes, we reconstruct the starch metabolic pathways in the two different types of plastids. Altogether, our results establish a comprehensive proteome map with post-translationally modified sites of potato chloroplast, which would provide the theoretical principle for the research of photosynthesis pathway and starch metabolism.
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 Four-week-old yellow potato (Solanum phureja) plants were inoculated with Phytophthora infestans and were collected and flash frozen in liquid nitrogen at 12 and 72 hours post inoculation, as well as mock inoculated, for RNA extraction. 2 yellow potato cultivars (resistant and susceptible) were used for each experiment. Mock inoculated plants were collected in each replicate. RNA obtained from each of the three biological replicates was pooled to obtain a single RNA sample for each timepoint X cultivar combination. A total of 6 different SAGE libraries were thus obtained. For all libraries, Illumina sequencing was performed at Canada´s Michael Smith Genome Sciences Centre.
Project description:Plants have a wide variety of ways to defend against pathogens. A commonly used model of the plant immune system divides it into a general response triggered by pathogen associated molecular patterns (PAMPs) and a specific response triggered by effectors. The first type of response is known as PAMP triggered immunity (PTI) and the second as effector-triggered immunity (ETI). We have performed a proteomical analysis of one PTI and two ETI models in potato and compared their effect on protein expression.
Project description:RNA was sequenced from commercially grown greenhouse minitubers treated with 10 ug of 1-(alpha-ethylbenzy)-3-nitroquanidine (NG) in DMSO and followed for four, and seven days post treatment. Control tubers were injected with DMSO alone. Sequence reads were mapped to the potato genome (PGSC_DM_v3_2.1.11) and transcript abundance was determined using Cuffdiff v 2.02.
Project description:Time series response of potato cv. Désirée, which is tolerant to PVY infection, was analysed in both inoculated as well as upper non-inoculated leaves. Additionally, transgenic plants deficient in accumulation of salicylic acid (NahG- Désirée) were studied in the same setting.
Project description:To gain novel molecular insights into quantitative late blight resistance, we performed a high-resolution quantitative analysis of gene expression using potato cultivars with contrasting SNP alleles at the StAOS2 locus associated with maturity corrected resistance (MCR). SuperSAGE samples were generated from uninfected and infected plants of the selected genotypes under controlled environmental conditions. Genotypes were pooled to reduce the influence of the genetic background on the transcriptome. Nine SuperSAGE samples were prepared from artificially inoculated plants in a growth chamber using total RNA of the pooled 14, 6 and 9 genotypes in groups A1, A2 and B2, respectively, at three infection time points T0, T1 and T2. Combining the tag counts of both NlaIII and DpnII libraries resulted in 1.1 to 6.2 million tags per sample. Of total 266361 unique tags (unitags), 52.6% matched to the potato genome sequence when up to three mismatches per 26 base pairs were allowed, and 23.3% matched without mismatch. Fifteen pair wise comparisons were performed between the nine SuperSAGE samples to identify transcripts that were differentially expressed in response to infection (six comparisons) or between three genotype pools at the infection time points T0, T1 and T2 (nine comparisons). The number of unitags per comparison ranged from 127 000 to 182 000 (average 158 000). Between 2100 and 11800 tags were differentially expressed in pair wise comparisons, depending on arbitrary cut-off p-values for a significant difference. The highest number of differences was observed for the comparison between genotype pools A1 and A2 one day after infection (A1-T1 vs A2-T1), and the lowest between genotype pools A2 and B2 two days after infection (B2-T2 vs A2-T2). The number of differences in response to infection and between genotype pools even before infection (T0) was in the same order of magnitude. Based on the annotations in the DFCI potato gene index, in the potato genome and in few cases by BLASTX searches against the protein database at NCBI, transcripts that showed reproducible differential expression over the infection time course or between genotype pools A1, A2 and B2 were grouped in 16 functional categories, with overlaps between categories. Genes with genotype dependent, constitutive differential expression provide excellent targets for developing novel diagnostic markers for breeding cultivars with improved quantitative resistance to late blight and possibly other biotic and abiotic stresses. Relevant in this respect appear, besides numerous genes of unknown or ill-defined function, genes with known function involved in stress responses, photosynthesis, protein biosynthesis, protein degradation via the 26S proteasome, transport of proteins, lipids, ions and other small molecules, cell wall structure and many others. Eighteen SuperSAGE libraries were constructed based on nine leaf samples from one infection experiment. For each time point (T0, T1 and T2) one leaflet each of 14, 6 and 9 SL genotypes in genotypic groups A1, A2 and B2, respectively, were pooled. Frozen pooled leaf tissue was powdered in a CryoMill. SuperSAGE libraries were generated at GenXPro GmbH (Frankfurt, Germany) essentially as described (Matsumura et al. 2010). To prevent amplification biases the TrueQuant technology was applied as described by B. Rotter (Patent application Nr. WO2009152928). Besides NlaIII (recognition site: 5M-bM-^@M-^Y-CATG-3M-bM-^@M-^Y), DpnII (recognition site: 5M-bM-^@M-^Y-GATC-3M-bM-^@M-^Y) was used as second anchoring enzyme, to capture transcripts without a NlaIII site. Therefore, the 26 bp tags carry either CATG or GATC at their 5M-bM-^@M-^Y end. The libraries were pooled and sequenced by Solexa/Illumina technology (Illumina, Inc., USA).