Project description:Responses to altered source–sink balance have been characterized in many crops at the physiological level, but the underlying genetic and molecular mechanisms are largely unknown. Detailed transcriptional profiling was performed in partially defoliated and shaded tomato plants to explore the effect of reduced source-to-sink ratio on molecular changes in the remaining source leaves. Transcription profiles of the remaining leaves 48 h after partial defoliation or partial shading were compared to leaves of control plants. Common significantly altered genes in the two treatments were assumed to be related to the reduced source-to-sink ratio. Sets of major genes in the abscisic acid, ethylene and gibberellin signal-transduction pathways were downregulated by both treatments. On the other hand, genes encoding cytokinin biosynthesis were upregulated. Most genes coding for transcription factors were also downregulated, especially those related to biotic and abiotic stress responses. Perhaps the most pronounced effect of reduced source-to-sink ratio was related to genes involved in the regulation of photosynthetic activity. Numerous genes coding for light-harvesting proteins, as well as those encoding plastocyanin, ferredoxin and ferredoxin NADP+ oxidoreductase were upregulated. Direct spectrophotometric analyses showed higher maximal potential activity of photosystem I with reduced source-to-sink ratio. As expected, the increased capacity for photosynthetic activity was associated with upregulation of almost all genes coding for the Calvin–Benson cycle and those encoding ATP biosynthesis in the mitochondria. Numerous transcriptional changes were observed 48 h after reducing source-to-sink ratio. Major genes in the photosynthetic-activity pathways were upregulated, whereas those in the pathways of defense mechanisms and responses to stress were downregulated. Genes involved in leaf senescence were also downregulated, suggesting that in addition to increased photosynthetic activity, the remaining leaves undergo a process of rejuvenation.
Project description:Tomato (Solanum lycopersicum) is a model crop for studying development regulation and ripening in flesh fruits and vegetables. Supplementary light to maintain the optimal light environment can lead to the stable growth of tomatoes in greenhouses and areas without sufficient daily light integral. Technological advances in genome-wide molecular phenotyping have dramatically enhanced our understanding of metabolic shifts in the plant metabolism across tomato fruit development. However, comprehensive metabolic and transcriptional behaviors along the developmental process under supplementary light provided by light-emitting diodes (LED) remain to be fully elucidated. We present integrative omic approaches to identify the impact on the metabolism of a single tomato plant leaf exposed to red LEDs of different intensities during the fruit development stage. Our special light delivery system, the “simplified source-sink model”, involves the exposure of a single leaf below the second truss to red LED light of different intensities. We evaluated fruit-size- and fruit-shape variations elicited by different light intensities. Our findings suggest that more than high-light treatment (500 mmol/m^2/s) with the red LED light is required to accelerate fruit growth for 2 weeks after anthesis. To investigate transcriptomic and metabolomic changes in leaf- and fruit samples we used microarray-, RNA sequencing-, and gas chromatography-mass spectrometry techniques. We found that metabolic shifts in the carbohydrate metabolism and in several key pathways contributed to fruit development, including ripening and cell-wall modification. Our findings suggest that the proposed workflow aids in the identification of key metabolites in the central metabolism that respond to monochromatic red-LED treatment and contribute to increase the fruit size of tomato plants. This study expands our understanding of systems-level responses mediated by low-, appropriate-, and high levels of red light irradiation in the fruit growth of tomato plants.
Project description:To characterize plant growth in net zero energy greenhouse models covered with semi-transparent organic solar cells (OSCs), RNA was extracted from tomato leaf tissue. Six experimental treatments were created with three OSC filters: FTAZ:IT-M, PTB7-Th:IEICO-4F, FTAZ:PCBM. Boxes with either a clear glass cover or a spectrally-neutral cover were used as the high light (HC) control and the comparative light intensity (PC) control, respectively. These treatments were divided into 2 experiments. 4 treatments (3 OSC boxes and control) had a consistent light intensity and were called the PPFD Controlled (PC) experiment. The other 4 treatments were the Height Controlled (HC) experiment and had more variation in light intensity between treatments due to a consistent distance from the growth chamber light source (height). Plants in the FP_PC treatment flowered one day later than the PC control. FI_PC flowered one day earlier. Gene expression in samples from the FP_PC treatment had a distinct pattern related to flowering initiation.
Project description:The tomato SlWRKY3 transcription factor was overexpressed in cultivated tomato (Solanum lycopersicum)and transgenic plants transcriptome was compared to that of wild-type plants.
Project description:Bamboo is one of the most important non-timber forestry products in the world. Light is not only the most critical source of energy for plant photosynthesis, but also involved in regulating the biological processes of plants. However, there are few reports on how blue/red light affects moso bamboo. This study investigated the growth status and physiological responses of moso bamboo (Phyllostachys edulis) to blue and red light treatments. The growth status of the bamboo plants was evaluated under different light conditions, revealing that both blue and red light treatments promoted plant height and overall growth compared to the dark treatment. Gas exchange parameters, chlorophyll fluorescence, and enzyme activity were measured to assess the photosystem response of moso bamboo to light treatments. Both blue and red light treatments significantly increased the net photosynthetic rate and stomatal conductance of the bamboo plants. Additionally, the blue light treatment led to higher chlorophyll content and enzyme activities related to photosynthesis and oxidative phosphorylation compared to the red light treatment.
Project description:We sequenced mRNA from immature green (15 days after anthesis) and red (Breaker+10 days) tomato (Solanum lycopersicum) fruit tissues from plants over-expressing SlGLK1 and SlGLK2 and from control plants 'M82' to compare gene expression levels between transgenic fruit and the control. Note: Samples in SRA were assigned the same sample accession. This is incorrect as there are different samples, hence “Source Name” was replaced with new values. Comment[ENA_SAMPLE] contains the original SRA sample accessions.
Project description:Source-to-sink carbon (C) allocation driven by the sink strength, i.e., the ability of a sink organ to import C, plays a central role in tissue growth and biomass productivity. However, molecular drivers of sink strength have not been thoroughly characterized in trees. Auxin, as a major plant phytohormone, regulates the mobilization of photoassimilates in source tissues and elevates the translocation of carbohydrates toward sink organs, including roots. In this study, we used an ‘auxin-stimulated carbon sink’ approach to understand the molecular processes involved in the long-distance source-sink C allocation in poplar. Poplar cuttings were foliar sprayed with polar auxin transport modulators, including auxin enhancers (AE) (i.e., IBA and IAA) and auxin inhibitor (AI) (i.e., NPA), followed by a comprehensive analysis of leaf, stem, and root tissues using biomass evaluation, phenotyping, C isotope labeling, metabolomics, and transcriptomics approaches. Auxin modulators altered root dry weight and branching pattern, and AE increased photosynthetically fixed C allocation from leaf to root tissues. The transcriptome analysis identified highly expressed genes in root tissue under AE condition including transcripts encoding polygalacturonase and β-amylase that could increase the sink size and activity. Metabolic analyses showed a shift in overall metabolism including an altered relative abundance levels of galactinol, and an opposite trend in citrate levels in root tissue under AE and AI conditions. In conclusion, we postulate a model suggesting that the source-sink C relationships in poplar could be fueled by mobile sugar alcohols, starch metabolism-derived sugars, and TCA-cycle intermediates as key molecular drivers of sink strength.
Project description:Plants growth and development is highly dependent on the environment. During there lifespan, plants are submitted to changing environmental conditions that requires constant metabolic adjustments. In particular, in vitro cultured plantlets are exposed, throughout micropropagation, to unique growth conditions characterized by distinctive levels of nitrogen, exogenous sugar, light and atmospheric conditions. To resume growth upon transfer ex vitro, in vitro plantlets must acclimatize to natural conditions. In this study, the impact of the in vitro environment on the expression profile of tomato (Solanum Lycopersicum) plantlets was analysed using the microarray and real-time PCR methods. After 20 days of growth in vitro, a significant increase in expression of genes linked to photosynthesis, nitrogen metabolism and salicylic acid signaling pathways was observed. By opposition, the expression of transcripts associated to carbohydrate metabolism and jasmonic acid signaling pathway were reduced. Also, the expression of reactive oxygen scavenging (ROS) enzymes in the mitochondrias, chloroplasts and cytosol were altered in in vitro cultured tomato plantlets. More precisely, the in vitro environment led to increased photosynthetic gene expression, lower sink strength, up-regulation of nitrogen assimilation and induced a specific stress response in tomato plantlets. Our results suggest that the presence of exogenous sugar is an important environmental cue that governs the modified cell ROS pattern, defense-related genes modulation and abnormal physiology of in vitro plantlets. Keywords: environmental challenge, growth condition comparison, expression profile