Nitrogen （N） is an essential macronutrient that affects plant growth and development. N is an important component of chlorophyll, amino acids, nucleic acids, and secondary metabolites. Nitrate is one ...of the most abundant N sources in the soil. Because nitrate and other N nutrients are often limiting, plants have developed sophisticated mechanisms to ensure adequate supply of nutrients in a variable environment. Nitrate is absorbed in the root and mobilized to other organs by nitrate transporters. Nitrate sensing activates signaling pathways that impinge upon molecular, metabolic, physiological, and developmental responses locally and at the whole plant level. With the advent of genomics technologies and genetic tools, important advances in our understanding of nitrate and other N nutrient responses have been achieved in the past decade. Furthermore, techniques that take advantage of natural polymor- phisms present in divergent individuals from a single species have been essential in uncovering new components. However, there are still gaps in our understanding of how nitrate signaling affects biolog- ical processes in plants. Moreover, we still lack an integrated view of how all the regulatory factors iden- tified interact or crosstalk to orchestrate the myriad N responses plants typically exhibit. In this review, we provide an updated overview of mechanisms by which nitrate is sensed and transported throughout the plant. We discuss signaling components and how nitrate sensing crosstalks with hormonal pathways for developmental responses locally and globally in the plant. Understanding how nitrate impacts on plant metabolism, physiology, and growth and development in plants is key to improving crops for sustainable agriculture.
Nitrate commands genome‐wide gene expression changes that impact metabolism, physiology, plant growth, and development. In an effort to identify new components involved in nitrate responses in ...plants, we analyze the Arabidopsis thaliana root phosphoproteome in response to nitrate treatments via liquid chromatography coupled to tandem mass spectrometry. 176 phosphoproteins show significant changes at 5 or 20 min after nitrate treatments. Proteins identified by 5 min include signaling components such as kinases or transcription factors. In contrast, by 20 min, proteins identified were associated with transporter activity or hormone metabolism functions, among others. The phosphorylation profile of NITRATE TRANSPORTER 1.1 (NRT1.1) mutant plants was significantly altered as compared to wild‐type plants, confirming its key role in nitrate signaling pathways that involves phosphorylation changes. Integrative bioinformatics analysis highlights auxin transport as an important mechanism modulated by nitrate signaling at the post‐translational level. We validated a new phosphorylation site in PIN2 and provide evidence that it functions in primary and lateral root growth responses to nitrate.
Synopsis
Phosphoproteomic analysis in response to nitrate treatment reveals early nitrate‐induced changes in Arabidopsis thaliana root phosphoproteins associated to signaling while late changes are associated to transport and hormone metabolism. Moreover, nitrate promotes the dephosphorylation of PIN2, impacting PIN2 subcellular localization and root development.
Several nitrate‐regulated phosphoproteins involved in signaling, metabolism and other functions were identified.
NRT1.1 is required for normal phosphoproteome responses to nitrate treatments.
Nitrate regulates root system architecture by modulating PIN2 phosphorylation status.
Phosphoproteomic analysis in response to nitrate treatment reveals early nitrate‐induced changes in Arabidopsis thaliana root phosphoproteins associated to signaling while late changes are associated to transport and hormone metabolism. Moreover, nitrate promotes the dephosphorylation of PIN2, impacting PIN2 subcellular localization and root development.
Abstract
Background and Aims
Cultured cell suspensions have been the preferred model to study the apoplast as well as to monitor metabolic and cell cycle-related changes. Previous work showed that ...methyl jasmonate (MeJA) inhibits leaf growth in a CORONATINE INSENSITIVE 1 (COI1)-dependent manner, with COI1 being the jasmonate (JA) receptor. Here, the effect of COI1 overexpression on the growth of stably transformed arabidopsis cell cultures is described.
Methods
Time-course experiments were carried out to analyse gene expression, and protein and metabolite levels.
Key Results
Both MeJA treatment and the overexpression of COI1 modify growth, by altering cell proliferation and expansion. DNA content as well as transcript patterns of cell cycle and cell wall remodelling markers were altered. COI1 overexpression also increases the protein levels of OLIGOGALACTURONIDE OXIDASE 1, BETA-GLUCOSIDASE/ENDOGLUCANASES and POLYGALACTURONASE INHIBITING PROTEIN2, reinforcing the role of COI1 in mediating defence responses and highlighting a link between cell wall loosening and growth regulation. Moreover, changes in the levels of the primary metabolites alanine, serine and succinic acid of MeJA-treated Arabidopsis cell cultures were observed. In addition, COI1 overexpression positively affects the availability of metabolites such as β-alanine, threonic acid, putrescine, glucose and myo-inositol, thereby providing a connection between JA-inhibited growth and stress responses.
Conclusions
This study contributes to the understanding of the regulation of growth and the production of metabolic resources by JAs and COI1. This will have important implications in dissecting the complex relationships between hormonal and cell wall signalling in plants. The work also provides tools to uncover novel mechanisms co-ordinating cell division and post-mitotic cell expansion in the absence of organ developmental control.
Transcriptional regulation, determined by the chromatin structure and regulatory elements interacting at promoter regions, is a key step in plant responses to environmental cues. Nitrate (NO3−) is a ...nutrient signal that regulates the expression of hundreds of genes in Arabidopsis thaliana. Here, we integrate mRNA sequencing, genome-wide RNA polymerase II (RNPII), chromatin immunoprecipitation sequencing, and DNase sequencing datasets to establish the relationship between RNPII occupancy and chromatin accessibility in response to NO3− treatments in Arabidopsis roots. Genomic footprinting allowed us to identify in vivo regulatory elements controlling gene expression in response to NO3− treatments. NO3−-modulated transcription factor (TF) footprints are important for a rapid increase in RNPII occupancy and transcript accumulation over time. We mapped key TF regulatory interactions and functionally validated the role of NAP, an NAC-domain containing TF, as a new regulatory factor in NO3− transport. Taken together, our study provides a comprehensive view of transcriptional networks in response to a nutrient signal in Arabidopsis roots.
NO3− treatments in Arabidopsis root produce changes in transcription factor (TF) footprints. This study mapped key TF regulatory interactions and validated the role of new TFs in the nitrate response in roots.
As sessile organisms, plants have to be able to adapt to a continuously changing environment. Plants that perceive some of these changes as stress signals activate signaling pathways to modulate ...their development and to enable them to survive. The complex responses to environmental cues are to a large extent mediated by plant hormones that together orchestrate the final plant response. The phytohormone cytokinin is involved in many plant developmental processes. Recently, it has been established that cytokinin plays an important role in stress responses, but does not act alone. Indeed, the hormonal control of plant development and stress adaptation is the outcome of a complex network of multiple synergistic and antagonistic interactions between various hormones. Here, we review the recent findings on the cytokinin function as part of this hormonal network. We focus on the importance of the crosstalk between cytokinin and other hormones, such as abscisic acid, jasmonate, salicylic acid, ethylene, and auxin in the modulation of plant development and stress adaptation. Finally, the impact of the current research in the biotechnological industry will be discussed.
Thirty-seven red wines from different varieties, origins, and styles were characterized to identify the chemical parameters that better correlate with wine astringency. Principal Component Analysis ...showed that tannin content was the most important parameter influencing overall astringency and its sub-quality dryness, followed by polyphenolic content, color index and, to a lesser extent, pH and alcoholic degree. Given that astringency is a textural sensation caused by the interaction between salivary proteins and tannins, a comparison between two tannin precipitation assays (i.e., methylcellulose, MCP; and Harbertson-Adams assays, HA) were performed to evaluate their ability as estimators of red wine astringency. Results of the sensory correlations showed that MCP and HA have a different behavior toward intensity of astringency and dryness, mainly influenced by the tannin concentration. HA exhibited a sigmoidal behavior with a better astringency predictive performance at low and mid tannin concentration range, whilst MCP showed a linear behavior with a better performance at high tannin concentration range.
•Astringency estimation is an important tool for quality management in red winemaking.•Tannin content is one of the most important parameters influencing astringency and its sub-quality dryness.•Polyphenolic content and color index are also positively correlated with astringency perception.•Tannin concentration influences the performance of analytical methods as estimators of wine astringency.
Soil salinity have a negative impact on plant growth and development. In this review, we highlight the role of auxin in salt stress responses and potential biotechnological approaches.
Abstract
As ...sessile organisms, plants are exposed to multiple abiotic stresses commonly found in nature. To survive, plants have developed complex responses that involve genetic, epigenetic, cellular, and morphological modifications. Among different environmental cues, salt stress has emerged as a critical problem contributing to yield losses and marked reductions in crop production. Moreover, as the climate changes, it is expected that salt stress will have a significant impact on crop production in the agroindustry. On a mechanistic level, salt stress is known to be regulated by the crosstalk of many signaling molecules such as phytohormones, with auxin having been described as a key mediator of the process. Auxin plays an important role in plant developmental responses and stress, modulating a complex balance of biosynthesis, transport, and signaling that among other things, finely tune physiological changes in plant architecture and Na+ accumulation. In this review, we describe current knowledge on auxin’s role in modulating the salt stress response. We also discuss recent and potential biotechnological approaches to tackling salt stress.
•Nitrate modulates hormonal pathways to adapt plant biology to environmental cues.•Hormones participate in local and systemic nitrogen signaling to regulate root and shoot growth.•Nitrate ...availability crosstalk with hormones to influence root system architecture.•This nitrate:hormone crosstalk also influences metabolism, uptake and stress responses.•Nitrate delays flowering time via the gibberellin signaling pathway.
Nitrate is an essential macronutrient for plants, a primary nitrogen source in natural and human-made ecosystems. Nitrate can also act as a signaling molecule that directs genome-wide gene expression changes with an impact on plant metabolism, physiology, growth and development. Nitrate and phytohormone signaling pathways crosstalk to modulate growth and developmental programs in a multifactorial manner. Nitrate-signaling controls plant growth and development using molecular mechanisms that involve phytohormone-signaling pathways. In contrast, many phytohormones modulate or impact nitrate signaling in interconnected pathways. In this review, we explore recent progress in our understanding of well-documented connections between nitrate and phytohormones such as auxin, cytokinin and abscisic acid. We also discuss recent studies connecting nitrate to other phytohormones such as ethylene, salicylic acid, gibberellins and brassinosteroids. While many molecular details remain to be elucidated, a number of core signaling components at the intersection between nitrate and the major hormonal pathways have been described. We focus on established interactions of nitrate and different hormonal pathways to bring about cellular, growth and developmental processes in Arabidopsis thaliana.
Soil salinity is a key problem for crop production worldwide. High salt concentration in soil negatively modulates plant growth and development. In roots, salinity affects the growth and development ...of both primary and lateral roots. The phytohormone auxin regulates various developmental processes during the plant's life cycle, including several aspects of root architecture. Auxin signaling involves the perception by specialized receptors which module several regulatory pathways. Despite their redundancy, previous studies have shown that their functions can also be context-specific depending on tissue, developmental or environmental cues. Here we show that the over-expression of Auxin Signaling F-Box 3 receptor results in an increased resistance to salinity in terms of root architecture and germination. We also studied possible downstream signaling components to further characterize the role of auxin in response to salt stress. We identify the transcription factor SZF1 as a key component in auxin-dependent salt stress response through the regulation of NAC4. These results give lights of an auxin-dependent mechanism that leads to the modulation of root system architecture in response to salt identifying a hormonal cascade important for stress response.
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