Explore the vast range of titles available.

Understanding the interactive effects and relationships between biochemical elements of tea leaves and the related factors, particularly climatic, cultivar, and geographic, is key for high-quality Ceylon tea production. The objectives of this study were to (1) investigate the effects of season × cultivar × agro-ecological regions (AERs) on the four tested biochemicals in fresh tea leaves, total polyphenol content (TPC), free sugar, protein, and theanine; (2) determine the relationships between, and develop a model to estimate, the biochemicals and their related factors; and (3) project the potential concentrations and distributions of four tested biochemicals in tea leaves with respect to the current and future climate. This study primarily uses inferential statistics via the Statistical Package for the Social Sciences (SPSS), cross-validation using R software, and the inverse distance weighting (IDW) approach in ArcGIS. The results demonstrate that the season, cultivar (Ceylon tea cultivars of TRI 2025 and TRI 4053), and AER and their interactions on biochemicals have significant effects (p < 0.05). The models derived in the regression analysis demonstrate the strong relationships between the independent variables and the biochemicals, with multiple correlation coefficients (R) around 0.8 and coefficient of determination (R2) around 0.6. The low standard deviation of error of prediction (SDEP < 0.1) and the high correlation coefficient of leave-one-out cross-validation (Q2) for all four biochemicals ranged from 0.56 to 0.61, which signifies the predictive ability of the models. The future projections show a considerable increase in the thresholds of all tested biochemicals. The distribution category with ‘very high’ concentrations of TPC and theanine is predicted to increase in the future by averages of 10% and 14%, respectively, while reducing the classes of protein and free sugar by 14% and 12%, respectively. Overall, the changing concentrations of the thresholds of relevant biochemicals and their distribution will negatively affect the final quality of tea, and these variations indicate that climate change has started to diminish Ceylon tea quality.

The Mediator16 (MED16; formerly termed SENSITIVE TO FREEZING6 [SFR6]) subunit of the plant Mediator transcriptional coactivator complex regulates cold-responsive gene expression in Arabidopsis thaliana, acting downstream of the C-repeat binding factor (CBF) transcription factors to recruit the core Mediator complex to cold-regulated genes. Here, we use loss-of-function mutants to show that RNA polymerase II recruitment to CBF-responsive cold-regulated genes requires MED16, MED2, and MED14 subunits. Transcription of genes known to be regulated via CBFs binding to the C-repeat motif/drought-responsive element promoter motif requires all three Mediator subunits, as does cold acclimation-induced freezing tolerance. In addition, these three subunits are required for low temperature-induced expression of some other, but not all, cold-responsive genes, including genes that are not known targets of CBFs. Genes inducible by darkness also required MED16 but required a different combination of Mediator subunits for their expression than the genes induced by cold. Together, our data illustrate that plants control transcription of specific genes through the action of subsets of Mediator subunits; the specific combination defined by the nature of the stimulus but also by the identity of the gene induced.

The Mediator complex controls transcription of most eukaryotic genes with individual subunits required for the control of particular gene regulons in response to various perturbations. In this study, we reveal the roles of the plant Mediator subunits MED16, MED14, and MED2 in regulating transcription in response to the phytohormone abscisic acid (ABA) and we determine which cis elements are under their control. Using synthetic promoter reporters we established an effective system for testing relationships between subunits and specific cis- acting motifs in protoplasts. Our results demonstrate that MED16, MED14, and MED2 are required for the full transcriptional activation by ABA of promoters containing both the ABRE (ABA-responsive element) and DRE (drought-responsive element). Using synthetic promoter motif concatamers, we showed that ABA-responsive activation of the ABRE but not the DRE motif was dependent on these three Mediator subunits. Furthermore, the three subunits were required for the control of water loss from leaves but played no role in ABA-dependent growth inhibition, highlighting specificity in their functions. Our results identify new roles for three Mediator subunits, provide a direct demonstration of their function and highlight that our experimental approach can be utilized to identify the function of subunits of plant transcriptional regulators.

African cities are growing rapidly into inefficient, unsustainable, resource-starved ecosystems that negatively affect the local economy and food production. Food as a critical resource needs to be produced and managed more efficiently by local communities in the urban area. Urban smart farming (USF) has emerged as an important mechanism to address these challenges to achieve sustainable, resilient, and inclusive cities. USF has the potential to be the industry 4.0 green revolution in agriculture, which embodies innovative digital technologies. However, it is unclear how local African communities and key stakeholders perceive this novel solution and if they are willing to engage in its uptake. This study examines the relationship between the perceived benefits and challenges of USF and the willingness of local African communities to actively participate in USF projects as a potential mechanism to improve local economy and food production. To assess this relationship, a causal model was developed. In this causal model, the local economy and food production were defined as dependent variables. The conceptualized model and the inherent causality between the constructs were validated through a survey administered among African cities’ residents. The results of structural equation modelling indicate a significant positive impact of perceived benefits of USF as well as the willingness of African communities to engage in this technology on local economy and food production. Only minimal adverse effects of the perceived challenges of USF on the local economy and food production have been found. The study concludes that the benefits and willingness of local communities are the key drivers for implementing urban smart farms in African metropolitans. Therefore, it is recommended to focus on the benefits and the motivation of local communities in African cities where USF shall be further developed, rather than on the barriers. The validated causal model can be used as a framework to facilitate the adoption of USF in Africa and consequently enhance the local economy and food production in African cities.

The plant mediator transcriptional co-activator complex consists of in the region of 34 protein subunits that collectively link promoter-bound transcription factors with the activity of RNA polymerase II. Among them, Mediator subunit 16 (MED16; also known as SENSITIVE TO FREEZING6, SFR6) plays a major role in regulating the expression of specific genes in response to a variety of stresses including cold, drought, UV and pathogen infection. The structure of plant mediator has been hypothesised to be similar to that of yeast mediator but has not yet been proven. Considering the structure of the yeast mediator complex, in which MED14, MED16 and MED2 occupy positions in the so-called “tail”, we would predict a close physical interaction between MED14, MED2 and MED16 in the plant complex. Therefore, this study investigated whether MED2 and MED14 control the same regulons as controlled by MED16. Results showed the necessity of these two proteins, like MED16, in gene regulation under cold, drought, and UV stresses and revealed a clear correlation between reduced levels of tolerance and impaired gene expression under cold and UV but not drought. To investigate whether particular domains within MED16 might be responsible for the activation of specific genes under different stresses, complementation experiments were used to test the ability of three different truncated MED16 versions to restore cold-, dark- and UV-inducible expression. Some truncated versions were able to complement the mutant but the degree of complementation varied amongst transgenic lines. Experiments were conducted to study the function of KIN10, an interacting protein of MED16 that appears to play a role similar to MED16 in regulation of stress genes and tolerance. The necessity of KIN10 in the control of a subset of the stress-inducible genes controlled by MED16 was demonstrated. Co-immunoprecipitation experiments revealed that regions within the N-terminal part of MED16 are essential for interaction with KIN10.