Jasmonates: biosynthesis, perception, signal transduction and action in plant stress response, growth and development. An update to the 2007 review in Annals of Botany

Plant gene responses to changing carbohydrate status can vary markedly Some genes are induced, some are repressed, and others are minimally affected As in microorganisms, sugar-sensitive plant genes are part of an ancient system of cellular adjustment to critical nutrient availability However, in multicellular plants, sugar-regulated expression also provides a mechanism for control of resource distribution among tissues and organs Carbohydrate depletion upregulates genes for photosynthesis, remobilization, and export, while decreasing mRNAs for storage and utilization Abundant sugar levels exert opposite effects through a combination of gene repression and induction Long-term changes in metabolic activity, resource partitioning, and plant form result Sensitivity of carbohydrate-responsive gene expression to environmental and developmental signals further enhances its potential to aid acclimation The review addresses the above from molecular to whole-plant levels and considers emerging models for sensing and transducing carbohydrate signals to responsive genes

Carbohydrate-modulated gene expression in plants.

Multimorbidity and the associated use of multiple medicines (polypharmacy), is common in the older population. Despite this, there is no consensus definition for polypharmacy. A systematic review was conducted to identify and summarise polypharmacy definitions in existing literature. The reporting of this systematic review conforms to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) checklist. MEDLINE (Ovid), EMBASE and Cochrane were systematically searched, as well as grey literature, to identify articles which defined the term polypharmacy (without any limits on the types of definitions) and were in English, published between 1st January 2000 and 30th May 2016. Definitions were categorised as i. numerical only (using the number of medications to define polypharmacy), ii. numerical with an associated duration of therapy or healthcare setting (such as during hospital stay) or iii. Descriptive (using a brief description to define polypharmacy). A total of 1156 articles were identified and 110 articles met the inclusion criteria. Articles not only defined polypharmacy but associated terms such as minor and major polypharmacy. As a result, a total of 138 definitions of polypharmacy and associated terms were obtained. There were 111 numerical only definitions (80.4% of all definitions), 15 numerical definitions which incorporated a duration of therapy or healthcare setting (10.9%) and 12 descriptive definitions (8.7%). The most commonly reported definition of polypharmacy was the numerical definition of five or more medications daily (n = 51, 46.4% of articles), with definitions ranging from two or more to 11 or more medicines. Only 6.4% of articles classified the distinction between appropriate and inappropriate polypharmacy, using descriptive definitions to make this distinction. Polypharmacy definitions were variable. Numerical definitions of polypharmacy did not account for specific comorbidities present and make it difficult to assess safety and appropriateness of therapy in the clinical setting.

/pdf/what-is-polypharmacy-a-systematic-review-of-definitions-4peoigk97w.pdf

What is polypharmacy? A systematic review of definitions

Circadian clocks are believed to confer an advantage to plants, but the nature of that advantage has been unknown. We show that a substantial photosynthetic advantage is conferred by correct matching of the circadian clock period with that of the external light-dark cycle. In wild type and in long- and short-circadian period mutants of Arabidopsis thaliana, plants with a clock period matched to the environment contain more chlorophyll, fix more carbon, grow faster, and survive better than plants with circadian periods differing from their environment. This explains why plants gain advantage from circadian control.

http://science.sciencemag.org/content/sci/309/5734/630.full.pdf

Plant Circadian Clocks Increase Photosynthesis, Growth, Survival, and Competitive Advantage

Plants respond to the changing seasons to initiate developmental programmes precisely at particular times of year. Flowering is the best characterized of these seasonal responses, and in temperate climates it often occurs in spring. Genetic approaches in Arabidopsis thaliana have shown how the underlying responses to changes in day length (photoperiod) or winter temperature (vernalization) are conferred and how these converge to create a robust seasonal response. Recent advances in plant genome analysis have demonstrated the diversity in these regulatory systems in many plant species, including several crops and perennials, such as poplar trees. Here, we report progress in defining the diverse genetic mechanisms that enable plants to recognize winter, spring and autumn to initiate flower development.

The genetic basis of flowering responses to seasonal cues

Leaf senescence is an essential developmental process that impacts dramatically on crop yields and involves altered regulation of thousands of genes and many metabolic and signaling pathways, resulting in major changes in the leaf. The regulation of senescence is complex, and although senescence regulatory genes have been characterized, there is little information on how these function in the global control of the process. We used microarray analysis to obtain a high-resolution time-course profile of gene expression during development of a single leaf over a 3-week period to senescence. A complex experimental design approach and a combination of methods were used to extract high-quality replicated data and to identify differentially expressed genes. The multiple time points enable the use of highly informative clustering to reveal distinct time points at which signaling and metabolic pathways change. Analysis of motif enrichment, as well as comparison of transcription factor (TF) families showing altered expression over the time course, identify clear groups of TFs active at different stages of leaf development and senescence. These data enable connection of metabolic processes, signaling pathways, and specific TF activity, which will underpin the development of network models to elucidate the process of senescence.

/pdf/high-resolution-temporal-profiling-of-transcripts-during-5e3w7ums29.pdf

High-Resolution Temporal Profiling of Transcripts during Arabidopsis Leaf Senescence Reveals a Distinct Chronology of Processes and Regulation

Potatoes (tubers of Solanum tuberosum ) are grown and eaten in more countries than any other crop, and in the global economy they are the fourth most important crop after the three cereals maize, rice, and wheat. Therefore, research into potato tuber initiation and development, which enables our

Multiple Signaling Pathways Control Tuber Induction in Potato

Photoperiod controls many developmental responses in animals, plants and even fungi. The response to photoperiod has evolved because daylength is a reliable indicator of the time of year, enabling developmental events to be scheduled to coincide with particular environmental conditions. Much progress has been made towards understanding the molecular mechanisms involved in the response to photoperiod in plants. These mechanisms include the detection of the light signal in the leaves, the entrainment of circadian rhythms, and the production of a mobile signal which is transmitted throughout the plant. Flowering, tuberization and bud set are just a few of the many different responses in plants that are under photoperiodic control. Comparison of what is known of the molecular mechanisms controlling these responses shows that, whilst common components exist, significant differences in the regulatory mechanisms have evolved between these responses.

https://nph.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1469-8137.2008.02681.x

Plant responses to photoperiod.

#### Summary points

About a fifth of the population in the United Kingdom is 60 years or older,1 yet people in this age group receive 59% of dispensed prescriptions and account for more than half of NHS drug costs.2 Older people often have several coexisting medical problems and take multiple drugs. Increasing age is associated with changes in pharmacokinetics and pharmacodynamics, so prescribing in this age group can be problematic.3

Many randomised controlled trials involving older patients focus on managing a single disease state, such as hypertension or osteoporosis, but people in this age group often have many interacting conditions and are taking many drugs, so guidance on their treatment often has to be based on consensus and involves extrapolating data derived from healthier patients. This review highlights some of the difficulties in prescribing in older patients and offers guidance for appropriate prescribing.

We searched the National Library for Health, PubMed, and Embase databases using the keywords “elderly” and “prescribing”, including synonyms by the MeSH or major descriptor headings. Our search was limited to studies undertaken in humans that were published in English during the past five years. We displayed abstracts of interest using Abstract Plus before obtaining the full text of articles of interest. In addition, we searched the Cochrane Library and our own personal archives of references

### Pharmacokinetic and pharmacodynamic changes

With age the body undergoes several changes that can affect the distribution, metabolism, and excretion of drugs. These …

/pdf/prescribing-for-older-people-3i61yangbr.pdf

Prescribing for older people

The onset of flowering in plants is regulated by complex gene networks that integrate multiple environmental and endogenous cues to ensure that flowering occurs at the appropriate time. This is achieved by precise control of the expression of key flowering genes at both the transcriptional and post-transcriptional level. In recent years, a class of small non-coding RNAs, called microRNAs (miRNAs), has been shown to regulate gene expression in a number of plant developmental processes and stress responses. MiRNA-based biotechnology, which harnesses the regulatory functions of such endogenous or artificial miRNAs, therefore represents a highly promising area of research. In this review, the process of plant miRNA biogenesis, their mode of action, and multiple regulatory functions are summarized. The roles of the miR156, miR172, miR159/319, miR390, and miR399 families in the flowering time regulatory network in Arabidopsis thaliana are discussed in depth.

/pdf/the-role-of-micrornas-in-the-control-of-flowering-time-oslbfaus8z.pdf

Stephen D. Jackson

Papers

High-Resolution Temporal Profiling of Transcripts during Arabidopsis Leaf Senescence Reveals a Distinct Chronology of Processes and Regulation

Multiple Signaling Pathways Control Tuber Induction in Potato

Plant responses to photoperiod.

Prescribing for older people

The role of microRNAs in the control of flowering time