Root Involvement in Plant Responses to Adverse Environmental Conditions

Climate change is altering the environment in which plants grow and survive. An increase in worldwide Earth surface temperatures has been already observed, together with an increase in the intensity of other abiotic stress conditions such as water deficit, high salinity, heavy metal intoxication, etc., generating harmful conditions that destabilize agricultural systems. Stress conditions deeply affect physiological, metabolic and morphological traits of plant roots, essential organs for plant survival as they provide physical anchorage to the soil, water and nutrient uptake, mechanisms for stress avoidance, specific signals to the aerial part and to the biome in the soil, etc. However, most of the work performed until now has been mainly focused on aerial organs and tissues. In this review, we summarize the current knowledge about the effects of different abiotic stress conditions on root molecular and physiological responses. First, we revise the methods used to study these responses (omics and phenotyping techniques). Then, we will outline how environmental stress conditions trigger various signals in roots for allowing plant cells to sense and activate the adaptative responses. Later, we discuss on some of the main regulatory mechanisms controlling root adaptation to stress conditions, the interplay between hormonal regulatory pathways and the global changes on gene expression and protein homeostasis. We will present recent advances on how the root system integrates all these signals to generate different physiological responses, including changes in morphology, long distance signaling and root exudation. Finally, we will discuss the new prospects and challenges in this field.

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High temperatures modify plant responses to abiotic stress conditions

Physiologia Plantarum ◽

10.1111/ppl.13151 ◽

2020 ◽

Vol 170 (3) ◽

pp. 335-344 ◽

Cited By ~ 3

Author(s):

Damián Balfagón ◽

Sara I. Zandalinas ◽

Ron Mittler ◽

Aurelio Gómez‐Cadenas

Keyword(s):

Abiotic Stress ◽

High Temperatures ◽

Stress Conditions ◽

Plant Responses

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Specific functions for Mediator complex subunits from different modules in the transcriptional response of Arabidopsis thaliana to abiotic stress

Scientific Reports ◽

10.1038/s41598-020-61758-w ◽

2020 ◽

Vol 10 (1) ◽

Cited By ~ 5

Author(s):

Tim Crawford ◽

Fazeelat Karamat ◽

Nóra Lehotai ◽

Matilda Rentoft ◽

Jeanette Blomberg ◽

...

Keyword(s):

Arabidopsis Thaliana ◽

Abiotic Stress ◽

Signaling Pathways ◽

Stress Responses ◽

Target Genes ◽

Biochemical Characterization ◽

Transcriptional Response ◽

Stress Conditions ◽

Important Player ◽

Adverse Environmental Conditions

AbstractAdverse environmental conditions are detrimental to plant growth and development. Acclimation to abiotic stress conditions involves activation of signaling pathways which often results in changes in gene expression via networks of transcription factors (TFs). Mediator is a highly conserved co-regulator complex and an essential component of the transcriptional machinery in eukaryotes. Some Mediator subunits have been implicated in stress-responsive signaling pathways; however, much remains unknown regarding the role of plant Mediator in abiotic stress responses. Here, we use RNA-seq to analyze the transcriptional response of Arabidopsis thaliana to heat, cold and salt stress conditions. We identify a set of common abiotic stress regulons and describe the sequential and combinatorial nature of TFs involved in their transcriptional regulation. Furthermore, we identify stress-specific roles for the Mediator subunits MED9, MED16, MED18 and CDK8, and putative TFs connecting them to different stress signaling pathways. Our data also indicate different modes of action for subunits or modules of Mediator at the same gene loci, including a co-repressor function for MED16 prior to stress. These results illuminate a poorly understood but important player in the transcriptional response of plants to abiotic stress and identify target genes and mechanisms as a prelude to further biochemical characterization.

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The function of S-nitrosothiols during abiotic stress in plants

Journal of Experimental Botany ◽

10.1093/jxb/erz197 ◽

2019 ◽

Vol 70 (17) ◽

pp. 4429-4439 ◽

Cited By ~ 18

Author(s):

Juan C Begara-Morales ◽

Mounira Chaki ◽

Raquel Valderrama ◽

Capilla Mata-Pérez ◽

Maria N Padilla ◽

...

Keyword(s):

Abiotic Stress ◽

Current Knowledge ◽

Stomatal Closure ◽

Cysteine Residue ◽

Detection Methods ◽

Plant Responses ◽

Wide Range ◽

Signaling Events

Abstract Nitric oxide (NO) is an active redox molecule involved in the control of a wide range of functions integral to plant biology. For instance, NO is implicated in seed germination, floral development, senescence, stomatal closure, and plant responses to stress. NO usually mediates signaling events via interactions with different biomolecules, for example the modulation of protein functioning through post-translational modifications (NO-PTMs). S-nitrosation is a reversible redox NO-PTM that consists of the addition of NO to a specific thiol group of a cysteine residue, leading to formation of S-nitrosothiols (SNOs). SNOs are more stable than NO and therefore they can extend and spread the in vivo NO signaling. The development of robust and reliable detection methods has allowed the identification of hundreds of S-nitrosated proteins involved in a wide range of physiological and stress-related processes in plants. For example, SNOs have a physiological function in plant development, hormone metabolism, nutrient uptake, and photosynthesis, among many other processes. The role of S-nitrosation as a regulator of plant responses to salinity and drought stress through the modulation of specific protein targets has also been well established. However, there are many S-nitrosated proteins that have been identified under different abiotic stresses for which the specific roles have not yet been identified. In this review, we examine current knowledge of the specific role of SNOs in the signaling events that lead to plant responses to abiotic stress, with a particular focus on examples where their functions have been well characterized at the molecular level.

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Crosstalk between Brassinosteroids and Ethylene during Plant Growth and under Abiotic Stress Conditions

International Journal of Molecular Sciences ◽

10.3390/ijms19103283 ◽

2018 ◽

Vol 19 (10) ◽

pp. 3283 ◽

Cited By ~ 15

Author(s):

Petra Jiroutova ◽

Jana Oklestkova ◽

Miroslav Strnad

Keyword(s):

Abiotic Stress ◽

Plant Growth ◽

Stress Conditions ◽

Signaling Networks ◽

Plant Responses ◽

Metabolic Systems ◽

Root And Shoot Growth ◽

Hormonal Crosstalk ◽

Main Effects

Plant hormones through signaling networks mutually regulate several signaling and metabolic systems essential for both plant development and plant responses to different environmental stresses. Extensive research has enabled the main effects of all known phytohormones classes to be identified. Therefore, it is now possible to investigate the interesting topic of plant hormonal crosstalk more fully. In this review, we focus on the role of brassinosteroids and ethylene during plant growth and development especially flowering, ripening of fruits, apical hook development, and root and shoot growth. As well as it summarizes their interaction during various abiotic stress conditions.

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Cyclophilins and Their Functions in Abiotic Stress and Plant–Microbe Interactions

Biomolecules ◽

10.3390/biom11091390 ◽

2021 ◽

Vol 11 (9) ◽

pp. 1390

Author(s):

Przemysław Olejnik ◽

Cezary J. Mądrzak ◽

Katarzyna Nuc

Keyword(s):

Abiotic Stress ◽

Molecular Mechanisms ◽

Expression Profiles ◽

Gene Expression Profiles ◽

Stress Conditions ◽

Regulatory Pathways ◽

Isomerase Activity ◽

Plant Microbe Interaction ◽

Microbe Interactions ◽

Fk506 Binding Proteins

Plants have developed a variety of mechanisms and regulatory pathways to change their gene expression profiles in response to abiotic stress conditions and plant–microbe interactions. The plant–microbe interaction can be pathogenic or beneficial. Stress conditions, both abiotic and pathogenic, negatively affect the growth, development, yield and quality of plants, which is very important for crops. In contrast, the plant–microbe interaction could be growth-promoting. One of the proteins involved in plant response to stress conditions and plant–microbe interactions is cyclophilin. Cyclophilins (CyPs), together with FK506-binding proteins (FKBPs) and parvulins, belong to a big family of proteins with peptidyl-prolyl cis-trans isomerase activity (Enzyme Commission (EC) number 5.2.1.8). Genes coding for proteins with the CyP domain are widely expressed in all organisms examined, including bacteria, fungi, animals, and plants. Their different forms can be found in the cytoplasm, endoplasmic reticulum, nucleus, chloroplast, mitochondrion and in the phloem space. They are involved in numerous processes, such as protein folding, cellular signaling, mRNA processing, protein degradation and apoptosis. In the past few years, many new functions, and molecular mechanisms for cyclophilins have been discovered. In this review, we aim to summarize recent advances in cyclophilin research to improve our understanding of their biological functions in plant defense and symbiotic plant–microbe interactions.

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Progressive Genomic Approaches to Explore Drought- and Salt-Induced Oxidative Stress Responses in Plants under Changing Climate

Plants ◽

10.3390/plants10091910 ◽

2021 ◽

Vol 10 (9) ◽

pp. 1910

Author(s):

Masum Billah ◽

Shirin Aktar ◽

Marian Brestic ◽

Marek Zivcak ◽

Abul Bashar Mohammad Khaldun ◽

...

Keyword(s):

Abiotic Stress ◽

Stress Responses ◽

Abiotic Stresses ◽

Crop Production ◽

Ecological Factors ◽

Crop Productivity ◽

Stress Conditions ◽

Plant Responses ◽

World Population ◽

Breeding Programs

Drought and salinity are the major environmental abiotic stresses that negatively impact crop development and yield. To improve yields under abiotic stress conditions, drought- and salinity-tolerant crops are key to support world crop production and mitigate the demand of the growing world population. Nevertheless, plant responses to abiotic stresses are highly complex and controlled by networks of genetic and ecological factors that are the main targets of crop breeding programs. Several genomics strategies are employed to improve crop productivity under abiotic stress conditions, but traditional techniques are not sufficient to prevent stress-related losses in productivity. Within the last decade, modern genomics studies have advanced our capabilities of improving crop genetics, especially those traits relevant to abiotic stress management. This review provided updated and comprehensive knowledge concerning all possible combinations of advanced genomics tools and the gene regulatory network of reactive oxygen species homeostasis for the appropriate planning of future breeding programs, which will assist sustainable crop production under salinity and drought conditions.

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Biostimulants Application in Horticultural Crops under Abiotic Stress Conditions

Agronomy ◽

10.3390/agronomy9060306 ◽

2019 ◽

Vol 9 (6) ◽

pp. 306 ◽

Cited By ~ 54

Author(s):

Roberta Bulgari ◽

Giulia Franzoni ◽

Antonio Ferrante

Keyword(s):

Abiotic Stress ◽

Abiotic Stresses ◽

Fruits And Vegetables ◽

Bioactive Molecules ◽

Plant Responses ◽

Vegetable Crops ◽

Horticultural Crops ◽

Breeding Programmes ◽

Adverse Environmental Conditions ◽

Performance Validation

Abiotic stresses strongly affect plant growth, development, and quality of production; final crop yield can be really compromised if stress occurs in plants’ most sensitive phenological phases. Additionally, the increase of crop stress tolerance through genetic improvements requires long breeding programmes and different cultivation environments for crop performance validation. Biostimulants have been proposed as agronomic tools to counteract abiotic stress. Indeed, these products containing bioactive molecules have a beneficial effect on plants and improve their capability to face adverse environmental conditions, acting on primary or secondary metabolism. Many companies are investing in new biostimulant products development and in the identification of the most effective bioactive molecules contained in different kinds of extracts, able to elicit specific plant responses against abiotic stresses. Most of these compounds are unknown and their characterization in term of composition is almost impossible; therefore, they could be classified on the basis of their role in plants. Biostimulants have been generally applied to high-value crops like fruits and vegetables; thus, in this review, we examine and summarise literature on their use on vegetable crops, focusing on their application to counteract the most common environmental stresses.

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The Possible Role of Non-Structural Carbohydrates in the Regulation of Tree Hydraulics

International Journal of Molecular Sciences ◽

10.3390/ijms21010144 ◽

2019 ◽

Vol 21 (1) ◽

pp. 144 ◽

Cited By ~ 10

Author(s):

Martina Tomasella ◽

Elisa Petrussa ◽

Francesco Petruzzellis ◽

Andrea Nardini ◽

Valentino Casolo

Keyword(s):

Water Transport ◽

Tree Mortality ◽

Current Knowledge ◽

Soluble Sugars ◽

Xylem Sap ◽

Published Data ◽

Plant Responses ◽

Long Distance ◽

Plant Hydraulics ◽

Frost Stress

The xylem is a complex system that includes a network of dead conduits ensuring long-distance water transport in plants. Under ongoing climate changes, xylem embolism is a major and recurrent cause of drought-induced tree mortality. Non-structural carbohydrates (NSC) play key roles in plant responses to drought and frost stress, and several studies putatively suggest their involvement in the regulation of xylem water transport. However, a clear picture on the roles of NSCs in plant hydraulics has not been drawn to date. We summarize the current knowledge on the involvement of NSCs during embolism formation and subsequent hydraulic recovery. Under drought, sugars are generally accumulated in xylem parenchyma and in xylem sap. At drought-relief, xylem functionality is putatively restored in an osmotically driven process involving wood parenchyma, xylem sap and phloem compartments. By analyzing the published data on stem hydraulics and NSC contents under drought/frost stress and subsequent stress relief, we found that embolism build-up positively correlated to stem NSC depletion, and that the magnitude of post-stress hydraulic recovery positively correlated to consumption of soluble sugars. These findings suggest a close relationship between hydraulics and carbohydrate dynamics. We call for more experiments on hydraulic and NSC dynamics in controlled and field conditions.

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Foes or Friends: ABA and Ethylene Interaction under Abiotic Stress

Plants ◽

10.3390/plants10030448 ◽

2021 ◽

Vol 10 (3) ◽

pp. 448

Author(s):

Maren Müller

Keyword(s):

Abiotic Stress ◽

Plant Growth ◽

Plant Hormones ◽

Plant Hormone ◽

Environmental Changes ◽

Current Knowledge ◽

Stomatal Closure ◽

Stress Conditions ◽

Hormone Interactions ◽

Hormone Signals

Due to their sessile nature, plants constantly adapt to their environment by modulating various internal plant hormone signals and distributions, as plants perceive environmental changes. Plant hormones include abscisic acid (ABA), auxins, brassinosteroids, cytokinins, ethylene, gibberellins, jasmonates, salicylic acid, and strigolactones, which collectively regulate plant growth, development, metabolism, and defense. Moreover, plant hormone crosstalk coordinates a sophisticated plant hormone network to achieve specific physiological functions, on both a spatial and temporal level. Thus, the study of hormone–hormone interactions is a competitive field of research for deciphering the underlying regulatory mechanisms. Among plant hormones, ABA and ethylene present a fascinating case of interaction. They are commonly recognized to act antagonistically in the control of plant growth, and development, as well as under stress conditions. However, several studies on ABA and ethylene suggest that they can operate in parallel or even interact positively. Here, an overview is provided of the current knowledge on ABA and ethylene interaction, focusing on abiotic stress conditions and a simplified hypothetical model describing stomatal closure / opening, regulated by ABA and ethylene.

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Plant Responses to Abiotic Stresses and Rhizobacterial Biostimulants: Metabolomics and Epigenetics Perspectives

Metabolites ◽

10.3390/metabo11070457 ◽

2021 ◽

Vol 11 (7) ◽

pp. 457

Author(s):

Motseoa M. Lephatsi ◽

Vanessa Meyer ◽

Lizelle A. Piater ◽

Ian A. Dubery ◽

Fidele Tugizimana

Keyword(s):

Abiotic Stresses ◽

Current Knowledge ◽

Plant Defence ◽

Plant Growth Promoting Rhizobacteria ◽

Plant Responses ◽

Plant Interactions ◽

Crop Quality ◽

Molecular Events ◽

Plant Growth Promoting ◽

Adverse Environmental Conditions

In response to abiotic stresses, plants mount comprehensive stress-specific responses which mediate signal transduction cascades, transcription of relevant responsive genes and the accumulation of numerous different stress-specific transcripts and metabolites, as well as coordinated stress-specific biochemical and physiological readjustments. These natural mechanisms employed by plants are however not always sufficient to ensure plant survival under abiotic stress conditions. Biostimulants such as plant growth-promoting rhizobacteria (PGPR) formulation are emerging as novel strategies for improving crop quality, yield and resilience against adverse environmental conditions. However, to successfully formulate these microbial-based biostimulants and design efficient application programs, the understanding of molecular and physiological mechanisms that govern biostimulant-plant interactions is imperatively required. Systems biology approaches, such as metabolomics, can unravel insights on the complex network of plant-PGPR interactions allowing for the identification of molecular targets responsible for improved growth and crop quality. Thus, this review highlights the current models on plant defence responses to abiotic stresses, from perception to the activation of cellular and molecular events. It further highlights the current knowledge on the application of microbial biostimulants and the use of epigenetics and metabolomics approaches to elucidate mechanisms of action of microbial biostimulants.

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