As sessile organisms, plants are unable to escape from the many abiotic and biotic factors that cause a departure from optimal conditions of growth and development. Low temperature represents one of the most harmful abiotic stresses affecting temperate plants. These species have adapted to seasonal variations in temperature by adjusting their metabolism during autumn, increasing their content of a range of cryo-protective compounds to maximise their cold tolerance. Some of these molecules are synthesised de novo. The down-regulation of some gene products represents an additional important regulatory mechanism. Ways in which plants cope with cold stress are described, and the current state of the art with respect to both the model plant Arabidopsis thaliana and crop plants in the area of gene expression and metabolic pathways during low-temperature stress are discussed.

Cold stress and acclimation – what is important for metabolic adjustment?

Improving crops yield under water-limited conditions is the most daunting challenge faced by breeders. To this end, accurate, relevant phenotyping plays an increasingly pivotal role for the selection of drought-resilient genotypes and, more in general, for a meaningful dissection of the quantitative genetic landscape that underscores the adaptive response of crops to drought. A major and universally recognized obstacle to a more effective translation of the results produced by drought-related studies into improved cultivars is the difficulty in properly phenotyping in a high-throughput fashion in order to identify the quantitative trait loci that govern yield and related traits across different water regimes. This review provides basic principles and a broad set of references useful for the management of phenotyping practices for the study and genetic dissection of drought tolerance and, ultimately, for the release of drought-tolerant cultivars.

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Phenotyping for drought tolerance of crops in the genomics era.

Plants face a combination of different abiotic stresses under field conditions which are lethal to plant growth and production. Simultaneous occurrence of chilling and drought stresses in plants due to the drastic and rapid global climate changes, can alter the morphological, physiological and molecular responses. Both these stresses adversely affect the plant growth and yields due to physical damages, physiological and biochemical disruptions, and molecular changes. In general, the co-occurrence of chilling and drought combination is even worse for crop production rather than an individual stress condition. Plants attain various common and different physiological and molecular protective approaches for tolerance under chilling and drought stresses. Nevertheless, plant responses to a combination of chilling and drought stresses are unique from those to individual stress. In the present review, we summarized the recent evidence on plant responses to chilling and drought stresses on shared as well as unique basis and tried to find a common thread potentially underlying these responses. We addressed the possible cross talk between plant responses to these stresses and discussed the potential management strategies for regulating the mechanisms of plant tolerance to drought and/or chilling stresses. To date, various novel approaches have been tested in minimizing the negative effects of combine stresses. Despite of the main improvements there is still a big room for improvement in combination of drought and chilling tolerance. Thus, future researches particularly using biotechnological and molecular approaches should be carried out to develop genetically engineered plants with enhanced tolerance against these stress factors.

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Chilling and Drought Stresses in Crop Plants: Implications, Cross Talk, and Potential Management Opportunities

Plant heat-shock proteins: A mini review

Plants are constantly exposed to a variety of environmental stresses. Freezing or extremely low temperature constitutes a key factor influencing plant growth, development and crop productivity. Plants have evolved a mechanism to enhance tolerance to freezing during exposure to periods of low, but non-freezing temperatures. This phenomenon is called cold acclimation. During cold acclimation, plants develop several mechanisms to minimize potential damages caused by low temperature. Cold response is highly complex process that involves an array of physiological and biochemical modifications. Furthermore, alterations of the expression patterns of many genes, proteins and metabolites in response to cold stress have been reported. Recent studies demonstrate that post-transcriptional and post-translational regulations play a role in the regulation of cold signaling. In this review article, recent advances in cold stress signaling and tolerance are highlighted.

Cold Signaling and Cold Response in Plants

Proteomics applied on plant abiotic stresses: Role of heat shock proteins (HSP)☆

Cold represents one of the major abiotic factors influencing plant growth and development worldwide. We analysed the long-term responsiveness of an Iranian spring wheat (cv. Kohdasht) to cold from a proteomic point of view, in order to unravel the molecular mechanisms helping a cold-sensitive cultivar to survive exposure to suboptimal temperatures. Plants were grown at 20 or 4°C until entering the reproductive stage and a cross-comparison on the leaf proteomes was performed. Quantitative analyses on protein alterations occurring upon low-temperature exposure showed a reinforcement in ascorbate recycling (dehydroascorbate reductase, ascorbate peroxidase) and protein processing (proteasome subunit, cysteine proteinase), as well as the accumulation of the enzyme devoted to tetrapyrrole resynthesis (glutamate semialdehyde aminomutase). In contrast, among proteins down-regulated after cold stress, we could identify some key Krebs cycle enzymes (isocitrate dehydrogenase, malate dehydrogenase), together with many photosynthesis-related proteins (oxygen-evolving complex proteins, ATP synthase subunits, ferredoxin NADPH oxidoreductase and some Calvin cycle enzymes). Physiological and biochemical parameters (such as shoot apex dissection, chlorophyll, proline and sugar content determination) sustained proteomics findings allowing the present research to contribute to the current knowledge on these long-term responses, which may be crucial to stress adaptation under field conditions.

Proteomic analysis of a spring wheat cultivar in response to prolonged cold stress

The influence of temperature on plant development in a vernalization-requiring winter wheat: A 2-DE based proteomic investigation.

Consumer complaints against the blandness of modern lean meat and the frequent reference to the more strongly flavored meat that was available years ago have prompted reconsideration of high fat-depositing typical pig breeds. Casertana and Large White pig breeds are characterized by a different tendency toward fat accumulation as they exhibit opposite genetic and physiological traits with respect to the energy metabolism. These physiological differences were investigated in longissimus lumborum muscles through proteomics (2-DE, MS/MS) and microarray approaches. Data were analyzed for pathway and network analyses, as well as GO term enrichment of biological functions. As a result, Casertana showed a greater amount of proteins involved in glycolitic metabolism and mainly rely on fast-mobilizable energy sources. Large White overexpressed cell cycle and skeletal muscle growth related genes. Metabolic behavior and other implications are discussed.

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Proteomics and transcriptomics investigation on longissimus muscles in Large White and Casertana pig breeds

Platelets represent a key cellular blood component under physiological conditions, due to their implications in the maintenance of vascular integrity and prevention of haemorrhagic phenomena1. Dysfunctions associated with thrombocytopenia constitute a significant threat to patients’ health. So far, administration of platelet concentrates (PCs) from healthy donors is the only known strategy for medical care of patients with active bleeding, thrombocytopenia caused by bone marrow dysfunctions or due to chemotherapy for treatments of malignancies, or upon preliminary treatments prior to stem cell transplantation. Qualitative and quantitative changes in platelets could also occur following coronary artery bypass surgery and trauma, and may represent a key indicator of likely thrombotic complications2. Platelets are basically collected from donors in two ways: extraction from whole blood throughout centrifugation (buffy-coat) or through apheresis. Both methods are currently employed and have bright sides and disadvantages. Analogously to other blood components, techniques to improve the shelf life of platelets (currently, only five days), while maintaining their safety and effectiveness, are under constant investigation worldwide. Indeed, blood transfusion services are always in shortage of PCs, because of the impossibility to prolong their storage in like fashion to hypothermic storage of erythrocyte concentrates or frozen storage of fresh frozen plasma. In order to improve storage of PCs, lowering temperature has been attempted as well, although results were not as positive as expected, since platelets do not tolerate refrigeration. Hypothermic (4°C) storage conditions cause deep modifications in platelet shape and functionality. These are relevant issues which compromise viability of cold stored platelets, as they exert their physiological role through their ability to change shape and activate under various conditions. Low temperature appears to be a triggering factor for activation as well, thus yielding yet activated platelets as unviable blood product at the end of the storage.

This review focuses on platelet storage temperatures and the main issues which affect both current (22 °C) and alternative (4 °C) storage protocols for PCs. In particular, we herein discuss the initial events which trigger morphological and physiological changes upon cold activation, partially distinguishable from physiological activation. Moreover, a glance will be given at recent proteomic approaches, which promise to improve current knowledge on blood components of transfusion interest, mainly addressing current technical hurdles (such as the analysis of membrane proteins and their reciprocal interaction).

Maria Giulia Egidi

Papers

Proteomics applied on plant abiotic stresses: Role of heat shock proteins (HSP)☆

Proteomic analysis of a spring wheat cultivar in response to prolonged cold stress

The influence of temperature on plant development in a vernalization-requiring winter wheat: A 2-DE based proteomic investigation.

Proteomics and transcriptomics investigation on longissimus muscles in Large White and Casertana pig breeds

Troubleshooting in platelet storage temperature and new perspectives through proteomics.