Project description:The timing of reproductive development determines spike architecture and thus yield in temperate grasses such as barley (Hordeum vulgare L.). Reproductive development in barley is controlled by the photoperiod response gene Ppd-H1 which accelerates flowering time under long-day (LD) conditions. A natural mutation in Ppd-H1 prevalent in spring barley causes a reduced photoperiod response, and thus, late flowering under LD. However, it is not very well understood how LD and Ppd-H1 control pre-anthesis development, and thus spike architecture and yield in barley. We performed a detailed morphological analysis of the pre-anthesis development in the spring barley cultivar Scarlett and its wild barley derived introgression line S42-IL107, carrying the photoperiod responsive Ppd-H1 allele. Characterization of shoot apex development in these genotypes indicated that floral transition and initiation of floral primordia occurred under LD (16h light/ 8h dark) and short day (SD, 8h light/ 16h dark) conditions, while inflorescence and seed development strictly required LDs. Additionally, a fast photoperiod response in the presence of the dominant Ppd-H1 allele promoted floret fertility under LDs. To characterize the effects of the photoperiod and allelic variation at Ppd-H1 on gene expression during pre-anthesis development we performed RNA sequencing of leaves and developing main shoot apices during the vegetative phase and early stages of inflorescence development in Scarlett and S42-IL107 grown under SD and LD conditions. Main shoot apices of both genotypes were sampled at defined developmental stages, i.e. Waddington stage W0.5, W1.0, W2.0 and W3.5, respectively. Leaf samples were harvested from plants before (W1.0) and after floral transition (W2.0). We identified genes that were specifically regulated at floral transition independent of day-length and Ppd-H1 and thus may serve as markers for the staging of floral transition. Furthermore, we identified transcripts differentially expressed between photoperiods and between genotypes in leaves and in shoot apices. This set of transcripts might act as candidates downstream of Ppd-H1 and are correlated with the promotion of shoot apex development and higher floret fertility under LD and in the presence of the photoperiod responsive Ppd-H1 allele.
Project description:Natural variation in the barley homolog of CENTRORADIALIS (HvCEN), was found to contribute to the expansion of barley cultivation into diverse habitats. It has been shown that induced hvcen mutants, originally designated as praematurum-c/maturity-c (mat-c) mutants, flowered a few days earlier under natural long-day conditions. All hvcen mutants flowered early and showed a reduction in spikelet number per spike, tiller number and yield in the outdoor experiments. Further evaluating development of main shoot apex of hvcen mutants and wild type under controlled long day and short day conditions showed that mutations in hvcen accelerated spikelet initiation and reduced axillary bud number in a photoperiod independent manner, but promoted floret development only under long days. In this project we investigate the pleiotropic effects of HvCEN on developmental timing and shoot and spike morphologies of barley and dependence on these effects on photoperiod. This RNAseq dataset was generated to identify the putative transcriptional targets of HvCEN. To this end, we used global transcriptome profiling in developing shoot apices and inflorescences of two allelic hvcen mutants (mat-c.907 and mat-c.943) and wild-type (Bonus) plants grown under long- and short-day photoperiods.
Project description:FLOWERING LOCUS T-like genes have duplicated and functionally diverged between dicot and monocots species. The purpose of this study was to characterize the function of HvFT3 in barley (Hordeum vulgare). For this purpose, we generated transgenic lines overexpressing HvFT3 and characterized its effects on global gene expression changes in the main shoot apices at two developmental stages (spikelet initiation, lemma primordium). Analysing the function of different HvFT homologs in barley gives important insights into the genetic control of spike development and hence of yield in barley.
Project description:Time-course in rice plants of the day length shift experiment in a growth chamber. Rice plants (cv. Norin 8) were collected at every 2h from dusk to noon on the day 0, 1, and 5 from the day length shift (a long-day conditon to a short-day condition).
Project description:We show that in Arabidopsis SIN3 LIKE (SNL)family genes encoding a scoffold protein for assembly of histone deacetylase complex, directly regulate the expression of an FT activator and three FT repressors to regulate the transition to flowering in short days and long days, respectively. Under inductive long days, SNLs including SIN3 LIKE 1(SNL1) to SNL5, function in partial redundancy to repress the expression of three AP2 family transcription factors that repress FT expression, and thus mediate long-day induction of FT expression and promote the transitiion to flowering. In contrast, under non-inductive short days SNLs act to inhibit the floral transition, partly through direct repression of a MADS box transcriptional factor that promotes FT expression. Thus, our results reveal that SNLs, through histone deacetylation, play a novel dual role for the control of flowering in the long-day plant Arabidopsis: inhibiting flowering when the day length is shorter and promoting the floral transition when days become longer than a threshold length.
Project description:INTRODUCTION: Blackcurrant (Ribes nigrum L.) is an excellent example of a “super fruit” with potential health benefits. Both genotype and cultivation environment are known to affect the chemical composition of blackcurrant, especially ascorbic acid and various phenolic compounds. Environmental conditions, like temperature, solar radiation and precipitation can also have significant impact on fruit chemical composition. The relevance of the study is further accentuated by the predicted and ongoing changes in global climate. </br> OBJECTIVES: The aim of the present study was to provide new knowledge and a deeper understanding of the effects of post flowering environmental conditions, namely temperature and day length, on fruit quality and chemical composition of blackcurrant using an untargeted high performance liquid chromatography–photo diode array–mass spectrometry (HPLC–PDA–MS) metabolomics approach. </br> METHODS: A phytotron experiment with cultivation of single-stemmed potted plants of blackcurrant cv. Narve Viking was conducted using constant temperatures of 12, 18 or 24 °C and three different photoperiods (short day, short day with night interruption, and natural summer daylight conditions). Plants were also grown under ambient outdoor conditions. Ripe berries were analysed using an untargeted HPLC–PDA–MS metabolomics approach to detect the presence and concentration of molecules as affected by controlled climatic factors. </br> RESULTS: The untargeted metabolomics dataset contained a total of 7274 deconvolved retention time-m/z pairs across both electrospray ionisation (ESI) positive and negative polarities, from which 549 metabolites were identified or minimally annotated based upon accurate mass MS. Conventional principal component analysis (PCA) in combination with the Friedman significance test were applied to first identify which metabolites responded to temperature in a linear fashion. Multi-block hierarchical PCA in combination with the Friedman significance test was secondly applied to identify metabolites that were responsive to different day length conditions. Temperature had significant effect on a total of 365 metabolites representing a diverse range of chemical classes. It was observed that ripening of the blackcurrant berries under ambient conditions, compared to controlled conditions, resulted in an increased accumulation of 34 annotated metabolites, mainly anthocyanins and flavonoids. 18 metabolites were found to be regulated differentially under the different daylength conditions. Moreover, based upon the most abundant anthocyanins, a comparison between targeted and untargeted analyses, revealed a close convergence of the two analytical methods. Therefore, the study not just illustrates the value of non-targeted metabolomics approaches with respect to the huge diversity and numbers of significantly changed metabolites detected (and which would be missed by conventional targeted analyses), but also shows the validity of the non-targeted approach with respect to its precision compared to targeted analyses. </br> CONCLUSIONS: Blackcurrant maturation under controlled ambient conditions revealed a number of insightful relationships between environment and chemical composition of the fruit. A prominent reduction of the most abundant anthocyanins under the highest temperature treatments indicated that blackcurrant berries in general may accumulate lower total anthocyanins in years with extreme hot summer conditions. HPLC–PDA–MS metabolomics is an excellent method for broad analysis of chemical composition of berries rich in phenolic compounds. Moreover, the experiment in controlled phytotron conditions provided additional knowledge concerning plant interactions with the environment.
Project description:Plant seeds prepare for germination already during seed maturation. We performed a detailed transcriptome analysis of barley grain maturation, desiccation and germination in two tissue fractions (endosperm/aleurone = e/a and embryo = em) using the Affymetrix barley1 chip. Experiment Overall Design: Barley developing and germinating seeds were harvested at different time points after flowering (developing) and imbibition (germinating). To further disseect the influence of different tissues, seeds were dissecte and tissues were analyzed individually.
Project description:There is growing evidence for the prevalence of DNA copy number variation (CNV) and its role in phenotypic variation in recent years. Comparative genomic hybridization (CGH) was used to explore the extent of this type of structural variation in the barley genome. In a panel of 14 genotypes including domesticated cultivars and wild barleys, we found that 14.9% of all the sequences on the array are affected by CNV. Higher levels of CNV diversity are present in the wild accessions relative to cultivated barley. A substantial portion (37%) of the CNV events are present in both wild and domesticated barley. CNVs are enriched in telomeric regions for all chromosomes except 4H, which is also the barley chromosome with the lowest proportion of CNVs. CNV affected 9.5% of the coding sequences represented on the array. The genes affected by CNV are enriched for sequences annotated as disease-resistance proteins and protein kinases, suggesting the potential for CNV to influence variation for responses to biotic and abiotic stress. The analysis of CNV breakpoints indicated that DNA repair mechanisms of double-strand breaks (DSBs) via single-stranded annealing (SSA) and synthesis-dependent strand annealing (SDSA) play an important role in the origin of many structural changes in barley. Here we present the first catalog of CNVs in a diploid Triticeae species, which opens the door for future genome diversity research in a tribe that comprises the economically important cereal species wheat, barley and rye. Our findings constitute a valuable resource for the identification of CNV affecting genes of agronomic importance.