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1.
The SnRK2 family in pepper (Capsicum annuum L.): genome-wide identification and expression analyses during fruit development and under abiotic stress.
Wu, Z, Cheng, J, Hu, F, Qin, C, Xu, X, Hu, K
Genes & genomics. 2020;(10):1117-1130
Abstract
Plant-specific SnRK2 (sucrose nonfermenting-1-related protein kinase 2) genes play crucial roles in the coordination of plant growth and development and responses to stress. However, comprehensive studies have not been performed for this gene family in pepper (Capsicum annuum), a very important Solanaceous vegetable worldwide. To fully understand the status of SnRK2s in chili pepper, a total of 9 putative SnRK2 genes (named CaSnRK2.1-2.9) were identified in pepper in the present study. These genes were located on 7 different chromosomes and classified into three subfamilies based on the phylogenetic tree. Their conserved motif compositions and exon-intron structures were systematically analyzed, and the results strongly supported the classification. Furthermore, a total of 81 putative cis-elements were found in the promoter regions, and the cis-elements related to hormone and stress signaling were abundant. Finally, the CaSnRK2 gene expression profiles among different tissues, especially developing fruit tissue, and under various abiotic stresses were investigated to identify tissue-specific or stress-responsive candidates. This study was the first to comprehensively investigate the SnRK2 family in pepper, and the results provide important clues for further functional analyses of fruit development and abiotic stress responses.
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2.
Is REDD1 a metabolic double agent? Lessons from physiology and pathology.
Britto, FA, Dumas, K, Giorgetti-Peraldi, S, Ollendorff, V, Favier, FB
American journal of physiology. Cell physiology. 2020;(5):C807-C824
Abstract
The Akt/mechanistic target of rapamycin (mTOR) signaling pathway governs macromolecule synthesis, cell growth, and metabolism in response to nutrients and growth factors. Regulated in development and DNA damage response (REDD)1 is a conserved and ubiquitous protein, which is transiently induced in response to multiple stimuli. Acting like an endogenous inhibitor of the Akt/mTOR signaling pathway, REDD1 protein has been shown to regulate cell growth, mitochondrial function, oxidative stress, and apoptosis. Recent studies also indicate that timely REDD1 expression limits Akt/mTOR-dependent synthesis processes to spare energy during metabolic stresses, avoiding energy collapse and detrimental consequences. In contrast to this beneficial role for metabolic adaptation, REDD1 chronic expression appears involved in the pathogenesis of several diseases. Indeed, REDD1 expression is found as an early biomarker in many pathologies including inflammatory diseases, cancer, neurodegenerative disorders, depression, diabetes, and obesity. Moreover, prolonged REDD1 expression is associated with cell apoptosis, excessive reactive oxygen species (ROS) production, and inflammation activation leading to tissue damage. In this review, we decipher several mechanisms that make REDD1 a likely metabolic double agent depending on its duration of expression in different physiological and pathological contexts. We also discuss the role played by REDD1 in the cross talk between the Akt/mTOR signaling pathway and the energetic metabolism.
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3.
Rapid On-Site Phenotyping via Field Fluorimeter Detects Differences in Photosynthetic Performance in a Hybrid-Parent Barley Germplasm Set.
Fernández-Calleja, M, Monteagudo, A, Casas, AM, Boutin, C, Pin, PA, Morales, F, Igartua, E
Sensors (Basel, Switzerland). 2020;(5)
Abstract
Crop productivity can be expressed as the product of the amount of radiation intercepted, radiation use efficiency and harvest index. Genetic variation for components of radiation use efficiency has rarely been explored due to the lack of appropriate equipment to determine parameters at the scale needed in plant breeding. On the other hand, responses of the photosynthetic apparatus to environmental conditions have not been extensively investigated under field conditions, due to the challenges posed by the fluctuating environmental conditions. This study applies a rapid, low-cost, and reliable high-throughput phenotyping tool to explore genotypic variation for photosynthetic performance of a set of hybrid barleys and their parents under mild water-stress and unstressed field conditions. We found differences among the genotypic sets that are relevant for plant breeders and geneticists. Hybrids showed lower leaf temperature differential and higher non-photochemical quenching, resembling closer the male parents. The combination of traits detected in hybrids seems favorable, and could indicate improved photoprotection and better fitness under stress conditions. Additionally, we proved the potential of a low-cost, field-based phenotyping equipment to be used routinely in barley breeding programs for early screening for stress tolerance.
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4.
Mechanisms of sensing and response to proteotoxic stress.
Santiago, AM, Gonçalves, DL, Morano, KA
Experimental cell research. 2020;(2):112240
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Abstract
Cells are continuously subject to various stresses, battling both exogenous insults as well as toxic by-products of normal cellular metabolism and nutrient deprivation. Throughout the millennia, cells developed a core set of general stress responses that promote survival and reproduction under adverse circumstances. Past and current research efforts have been devoted to understanding how cells sense stressors and how that input is deciphered and transduced, resulting in stimulation of stress management pathways. A prime element of cellular stress responses is the increased transcription and translation of proteins specialized in managing and mitigating distinct types of stress. In this review, we focus on recent developments in our understanding of cellular sensing of proteotoxic stressors that impact protein synthesis, folding, and maturation provided by the model eukaryote the budding yeast, Saccharomyces cerevisiae, with reference to similarities and differences with other model organisms and humans.
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5.
Brassinosteroids: Multidimensional Regulators of Plant Growth, Development, and Stress Responses.
Nolan, TM, Vukašinović, N, Liu, D, Russinova, E, Yin, Y
The Plant cell. 2020;(2):295-318
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Abstract
Brassinosteroids (BRs) are a group of polyhydroxylated plant steroid hormones that are crucial for many aspects of a plant's life. BRs were originally characterized for their function in cell elongation, but it is becoming clear that they play major roles in plant growth, development, and responses to several stresses such as extreme temperatures and drought. A BR signaling pathway from cell surface receptors to central transcription factors has been well characterized. Here, we summarize recent progress toward understanding the BR pathway, including BR perception and the molecular mechanisms of BR signaling. Next, we discuss the roles of BRs in development and stress responses. Finally, we show how knowledge of the BR pathway is being applied to manipulate the growth and stress responses of crops. These studies highlight the complex regulation of BR signaling, multiple points of crosstalk between BRs and other hormones or stress responses, and the finely tuned spatiotemporal regulation of BR signaling.
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Molecular Mapping and Genomics of Grain Yield in Durum Wheat: A Review.
Arriagada, O, Marcotuli, I, Gadaleta, A, Schwember, AR
International journal of molecular sciences. 2020;(19)
Abstract
Durum wheat is the most relevant cereal for the whole of Mediterranean agriculture, due to its intrinsic adaptation to dryland and semi-arid environments and to its strong historical cultivation tradition. It is not only relevant for the primary production sector, but also for the food industry chains associated with it. In Mediterranean environments, wheat is mostly grown under rainfed conditions and the crop is frequently exposed to environmental stresses, with high temperatures and water scarcity especially during the grain filling period. For these reasons, and due to recurrent disease epidemics, Mediterranean wheat productivity often remains under potential levels. Many studies, using both linkage analysis (LA) and a genome-wide association study (GWAS), have identified the genomic regions controlling the grain yield and the associated markers that can be used for marker-assisted selection (MAS) programs. Here, we have summarized all the current studies identifying quantitative trait loci (QTLs) and/or candidate genes involved in the main traits linked to grain yield: kernel weight, number of kernels per spike and number of spikes per unit area.
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Class III peroxidase: an indispensable enzyme for biotic/abiotic stress tolerance and a potent candidate for crop improvement.
Kidwai, M, Ahmad, IZ, Chakrabarty, D
Plant cell reports. 2020;(11):1381-1393
Abstract
Class III peroxidases are secretory enzymes which belong to a ubiquitous multigene family in higher plants and have been identified to play role in a broad range of physiological and developmental processes. Potentially, it is involved in generation and detoxification of hydrogen peroxide (H2O2), and their subcellular localization reflects through three different cycles, namely peroxidative cycle, oxidative and hydroxylic cycles to maintain the ROS level inside the cell. Being an antioxidant, class III peroxidases are an important initial defence adapted by plants to cope with biotic and abiotic stresses. Both these stresses have become a major concern in the field of agriculture due to their devastating effect on plant growth and development. Despite numerous studies on plant defence against both the stresses, only a handful role of class III peroxidases have been uncovered by its functional characterization. This review will cover our current understanding on class III peroxidases and the signalling involved in their regulation under both types of stresses. The review will give a view of class III peroxidases and highlights their indispensable role under stress conditions. Its future application will be discussed to showcase their importance in crop improvement by genetic manipulation and by transcriptome analysis.
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8.
Molecular Regulation of Plant Responses to Environmental Temperatures.
Ding, Y, Shi, Y, Yang, S
Molecular plant. 2020;(4):544-564
Abstract
Temperature is a key factor governing the growth and development, distribution, and seasonal behavior of plants. The entire plant life cycle is affected by environmental temperatures. Plants grow rapidly and exhibit specific changes in morphology under mild average temperature conditions, a response termed thermomorphogenesis. When exposed to chilling or moist chilling low temperatures, flowering or seed germination is accelerated in some plant species; these processes are known as vernalization and cold stratification, respectively. Interestingly, once many temperate plants are exposed to chilling temperatures for some time, they can acquire the ability to resist freezing stress, a process termed cold acclimation. In the face of global climate change, heat stress has emerged as a frequent challenge, which adversely affects plant growth and development. In this review, we summarize and discuss recent progress in dissecting the molecular mechanisms regulating plant thermomorphogenesis, vernalization, and responses to extreme temperatures. We also discuss the remaining issues that are crucial for understanding the interactions between plants and temperature.
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Enhancing Salt Tolerance of Plants: From Metabolic Reprogramming to Exogenous Chemical Treatments and Molecular Approaches.
Patel, MK, Kumar, M, Li, W, Luo, Y, Burritt, DJ, Alkan, N, Tran, LP
Cells. 2020;(11)
Abstract
Plants grow on soils that not only provide support for root anchorage but also act as a reservoir of water and nutrients important for plant growth and development. However, environmental factors, such as high salinity, hinder the uptake of nutrients and water from the soil and reduce the quality and productivity of plants. Under high salinity, plants attempt to maintain cellular homeostasis through the production of numerous stress-associated endogenous metabolites that can help mitigate the stress. Both primary and secondary metabolites can significantly contribute to survival and the maintenance of growth and development of plants on saline soils. Existing studies have suggested that seed/plant-priming with exogenous metabolites is a promising approach to increase crop tolerance to salt stress without manipulation of the genome. Recent advancements have also been made in genetic engineering of various metabolic genes involved in regulation of plant responses and protection of the cells during salinity, which have therefore resulted in many more basic and applied studies in both model and crop plants. In this review, we discuss the recent findings of metabolic reprogramming, exogenous treatments with metabolites and genetic engineering of metabolic genes for the improvement of plant salt tolerance.
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10.
Bacterial Evolution in High-Osmolarity Environments.
Cesar, S, Anjur-Dietrich, M, Yu, B, Li, E, Rojas, E, Neff, N, Cooper, TF, Huang, KC
mBio. 2020;(4)
Abstract
Bacteria must maintain a cytosolic osmolarity higher than that of their environment in order to take up water. High-osmolarity environments therefore present formidable stress to bacteria. To explore the evolutionary mechanisms by which bacteria adapt to high-osmolarity environments, we selected Escherichia coli in media with a variety of osmolytes and concentrations for 250 generations. Adaptation was osmolyte dependent, with sorbitol stress generally resulting in increased fitness under conditions with higher osmolarity, while selection in high concentrations of proline resulted in increased fitness specifically on proline. Consistent with these phenotypes, sequencing of the evolved populations showed that passaging in proline resulted in specific mutations in an associated metabolic pathway that increased the ability to utilize proline for growth, while evolution in sorbitol resulted in mutations in many different genes that generally resulted in improved growth under high-osmolarity conditions at the expense of growth at low osmolarity. High osmolarity decreased the growth rate but increased the mean cell volume compared with growth on proline as the sole carbon source, demonstrating that osmolarity-induced changes in growth rate and cell size follow an orthogonal relationship from the classical Growth Law relating cell size and nutrient quality. Isolates from a sorbitol-evolved population that captured the likely temporal sequence of mutations revealed by metagenomic sequencing demonstrated a trade-off between growth at high osmolarity and growth at low osmolarity. Our report highlights the utility of experimental evolution for dissecting complex cellular networks and environmental interactions, particularly in the case of behaviors that can involve both specific and general metabolic stressors.IMPORTANCE For bacteria, maintaining higher internal solute concentrations than those present in the environment allows cells to take up water. As a result, survival is challenging in high-osmolarity environments. To investigate how bacteria adapt to high-osmolarity environments, we maintained Escherichia coli in a variety of high-osmolarity solutions for hundreds of generations. We found that the evolved populations adopted different strategies to improve their growth rates depending on the osmotic passaging condition, either generally adapting to high-osmolarity conditions or better metabolizing the osmolyte as a carbon source. Single-cell imaging demonstrated that enhanced fitness was coupled to faster growth, and metagenomic sequencing revealed mutations that reflected growth trade-offs across osmolarities. Our study demonstrated the utility of long-term evolution experiments for probing adaptation occurring during environmental stress.