Project description:The experiment followed transcriptional changes during potato tuber induction from a stolon tip to a tuber. Samples were taken at stage 1, stage 3, stage 4 and stage 5 according to Kloosterman et al., 2005
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:For expression profiling analyses of early stages of tuber induction, plants of Solanum tuberosum ssp andigena (7540) were used. This wild subspecies is strictly dependent on photoperiod for tuberisation, such that short days (SD) inductive conditions are required in order to trigger tuber induction in the stolons. Andigena plants were grown in the greenhouse under LD non-inductive conditions until a 10-leaf stage. They were subsequently transferred to inductive SD conditions (8 h light/16 h dark), and sampled at 0, 2, 4, 6 and 8 days after transfer to SDs. Tuber swelling was visible approximately 6-8 days after transfer to inductive conditions. The apical region of the stolons (2 cm) was collected one hour before the beginning of the light period.
Project description:The consequences on tuber transcriptome of a short heat period during tuber development was investigated in this study with special regard to the development of secondary tuber growth. Plants were grown for 47 days in the greenhouse under ambient conditions (21°C/ 19°C, 16h light, 8h dark) before application of mild heat stress temperatures (29°C/27°C) to one group of plants for 7 days and a stress release period on control temperature for 2 more weeks until harvest. Leaves were sampled before the heat period, at the end of the heat period and at harvest, two weeks after stress release. Tuber samples were taken at harvest. Tubers grown at normal temperatures and exhibiting a normal growth phenotype were used as control. Tubers subjected to the heat treatment and exhibiting a second-growth phenotype (chain tubers) were grouped into primary (attached to stolon from plant) and secondary tubers (attached to stolon from primary tuber).
Project description:Although significant work has been undertaken regarding the response of model and crop plants to heat shock during the acclimatory phase, few studies have examined the steady state response to the mild heat stress encountered in temperate agriculture. In the present work we therefore exposed tuberising potato plants to mildly elevated temperatures (30/20C), day/night) for up to five weeks and compared tuber yield, physiological and biochemical responses, and leaf and tuber metabolomes and transcriptomes with plants grown under optimal conditions (22/16C). Growth at elevated temperature reduced tuber yield despite an increase in net foliar photosynthesis. This was associated with major shifts in leaf and tuber metabolite profiles, a significant decrease in leaf glutathione redox state and decreased starch synthesis in tubers. Furthermore, growth at elevated temperature had a profound impact on leaf and tuber transcript expression with large numbers of transcripts displaying a rhythmic oscillation at the higher growth temperature. RT-PCR revealed perturbation in the expression of circadian clock transcripts including StSP6A, previously identified as a tuberisation signal. Our data indicate that potato plants grown at moderately elevated temperatures do not exhibit classic symptoms of abiotic stress but that tuber development responds via a diversity of biochemical and molecular signals. In this submission we are looking at gene expression changes with respect to both temperature and time, every 4h over a 24h period whereby diurnal changes may be apparent.