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Authors: Victoria Berdion Gabarain, Miguel A. Ibeas, Hernan Salinas-Grennet and José M. Estevez.
Molecular Plant (2024)
Excerpts: "A recent study published in Molecular Plant led by Prof. Chao Li (Lu et al. 2024) provides strong evidence that the targeting of TRANSPORT INHIBITOR RESPONSE 1 (TIR1)/AUXIN-SIGNALING F-BOX 2 (AFB2) to the nucleus is dependent on the oxidation triggered by auxin. The results of this work demonstrate that biologically active ROS, specifically hydrogen peroxide (H2O2) and nitric oxide (NO), play both a crucial role in the localization of TIR1/AFB2 proteins between the nucleus and cytoplasm in RHs (Figure 1)."
"The oxidized versions of TIR1 and AFB2 are essential for improving the effectiveness of TIR1 and AFB2 in transcriptional auxin responses in RH growth. Overall, a new mechanism is proposed by which auxin promotes the movement of TIR1/AFB2 from the cytoplasm to the nucleus and this process is controlled by the FER-ROS signaling pathway. The authors illuminate the complex interactions between auxin signaling pathways, redox signaling molecules, and protein changes that drive plant growth and development."
Authors: Baiyan Lu, Shengnan Wang, Hanqian Feng, Jing Wang, Kaixing Zhang, Yilin Li, Ping Wu, Minmin Zhang, Yanshu Xia, Chao Peng and Chao Li.
Molecular Plant (2024)
Short Summary: Auxin activates the FER/LLG1–RAC/ROP pathway to stimulate ROS and NO production in root hair cells, which leads to oxidative modifications of TIR1 C140/C516/AFB2 C135/C511 and in turn their transport from the cytoplasm to nucleus, whereby regulates the auxin responsive genes’ expression.
Abstract: "The phytohormone auxin plays a pivotal role in governing plant growth and development. While the TRANSPORT INHIBITOR RESPONSE1/AUXIN SIGNALING F-BOX (TIR1/AFBs) receptors function in both the nucleus and cytoplasm, the mechanism governing the distribution of TIR1/AFBs between these small cellular compartments remains unknown. In this study, we demonstrate that auxin-mediated oxidation of TIR1/AFB2 is essential for their targeting to the nucleus. Our findings reveal that small active molecules, reactive oxygen species (ROS) and nitric oxide (NO), are indispensable for the nucleo-cytoplasmic distribution of TIR1/AFB2 in trichoblasts and root hairs. This process is regulated by the FERONIA receptor kinase–NADPH oxidase signaling pathway. ROS and NO initiate oxidative modifications in TIR1 C140/516 and AFB2 C135/511, facilitating their subsequent nuclear import. The oxidized forms of TIR1 C140/516 and AFB2 C135/511 play a crucial role in enhancing the functionality of TIR1 and AFB2 in transcriptional auxin responses. In summary, our study unveils a novel mechanism through which auxin stimulates the transportation of TIR1/AFB2 from the cytoplasm to the nucleus, orchestrated by the FERONIA–ROS signaling pathway."
Authors: Cheng Zhang, Charles Tetteh, Sheng Luo, Pinyuan Jin, Xingqian Hao, Min Sun, Nan Fang, Yingjun Liu and Huajian Zhang.
Molecular Plant Pathology (2024)
Abstract: Pectin has been extensively studied in animal immunity, and exogenous pectin as a food additive can provide protection against inflammatory bowel disease. However, the utility of pectin to improve immunity in plants is still unstudied. Here, we found exogenous application of pectin triggered stomatal closure in Arabidopsis in a dose- and time-dependent manner. Additionally, pectin activated peroxidase and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase to produce reactive oxygen species (ROS), which subsequently increased cytoplasmic Ca2+ concentration ([Ca2+]cyt) and was followed by nitric oxide (NO) production, leading to stomatal closure in an abscisic acid (ABA) and salicylic acid (SA) signalling-dependent mechanism. Furthermore, pectin enhanced the disease resistance to Pseudomonas syringae pv. tomato DC3000 (Pst DC3000) with mitogen-activated protein kinases (MPKs) MPK3/6 activated and upregulated expression of defence-responsive genes in Arabidopsis. These results suggested that exogenous pectin-induced stomatal closure was associated with ROS and NO production regulated by ABA and SA signalling, contributing to defence against Pst DC3000 in Arabidopsis.
Authors: Robert D. Hill, Abir U. Igamberdiev and Claudio Stasolla.
Planta (2023)
Main conclusion: The preservation of quiescent center stem cell integrity in hypoxic roots by phytoglobins is exercised through their ability to scavenge nitric oxide and attenuate its effects on auxin transport and cell degradation. Under low oxygen stress, the retention or induction of phytoglobin expression maintains cell viability while loss or lack of induction of phytoglobin leads to cell degradation.
Abstract: "Plants have evolved unique attributes to ensure survival in the environment in which they must exist. Common among the attributes is the ability to maintain stem cells in a quiescent (or low proliferation) state in unfriendly environments. From the seed embryo to meristematic regions of the plant, quiescent stem cells exist to regenerate the organism when environmental conditions are suitable to allow plant survival. Frequently, plants dispose of mature cells or organs in the process of acclimating to the stresses to ensure survival of meristems, the stem cells of which are capable of regenerating cells and organs that have been sacrificed, a feature not generally available to mammals. Most of the research on plant stress responses has dealt with how mature cells respond because of the difficulty of specifically examining plant meristem responses to stress. This raises the question as to whether quiescent stem cells behave in a similar fashion to mature cells in their response to stress and what factors within these critical cells determine whether they survive or degrade when exposed to environmental stress. This review attempts to examine this question with respect to the quiescent center (QC) stem cells of the root apical meristem. Emphasis is put on how varying levels of nitric oxide, influenced by the expression of phytoglobins, affect QC response to hypoxic stress."
Authors: Su Li, Hao Yu Wang, Yue Zhang, Jing Huang, Zhijian Chen, Ren Fang Shen and Xiao Fang Zhu.
Science of the Total Environment (2023)
Highlights: • Cd induced endogenous auxin accumulation. • Exogenous auxin inhibited the fixation of Cd in the root cell wall hemicellulose. • Auxin decreased expression of genes involved in Cd absorption and translocation. • Auxin up-regulated expression of genes involved in Cd efflux and sequestration. • Auxin decrease Cd accumulation in rice, a process might mediate by NO signaling.
Abstract: "Although auxin has been linked to plants' responses to cadmium (Cd) stress, the exact mechanism is yet elusive. The objective of the current investigation was to determine the role and the mechanism of auxin in controlling rice's Cd accumulation. Rice roots with Cd stress have higher endogenous auxin levels, and exogenous auxin combined Cd treatment could reduce root cell wall's hemicellulose content when compared with Cd treatment alone, which in turn reduced its fixation of Cd, as well as decreased the expression of OsCd1 (a major facilitator superfamily gene), OsNRAMP1/5 (Natural Resistance-Associated Macrophage Protein 1/5), OsZIP5/9 (Zinc Transporter 5/9), and OsHMA2 (Heavy Metal ATPase 2) that participated in Cd uptake and root to shoot translocation. Furthermore, less Cd accumulated in the shoots as a result of auxin's impact in increasing the expression of OsCAL1 (Cadmium accumulation in Leaf 1), OsABCG36/OsPDR9 (G-type ATP-binding cassette transporter/Pleiotropic drug resistance 9), and OsHMA3, which were in charge of Cd efflux and sequestering into vacuoles, respectively. Additionally, auxin decreased endogenous nitric oxide (NO) levels and antioxidant enzyme activity, while treatment of a NO scavenger-cPTIO-reduced auxin's alleviatory effects. In conclusion, the rice's ability to tolerate Cd toxicity was likely increased by the auxin-accelerated cell wall Cd exclusion mechanism, a pathway that controlled by the buildup of NO."
Authors: Muhammad Saad Shoaib Khan, Sulaiman Ahmed, Aziz ul Ikram, Fakhir Hannan, Muhammad Umair Yasin, Jin Wang, Biying Zhao, Faisal Islam and Jian Chen.
Physiologia Plantarum (2023)
Highlights: • Melatonin acts as a redox network regulator in plants via regulating secondary messengers signaling. • Melatonin regulates the activity of redox-sensitive proteins and transcription factors. • Melatonin influences gene expression and physiological processes in response to stresses. • Melatonin synergically work with other hormones to confer plant resistance and stress adaptability.
Abstract: "Plants being sessile in nature, are exposed to unwarranted threats as a result of constantly changing environmental conditions. These adverse factors can have negative impacts on their growth, development, and yield. Hormones are key signaling molecules enabling cells to respond rapidly to different external and internal stimuli. In plants, melatonin (MT) plays a critical role in the integration of various environmental signals and activation of stress-response networks to develop defense mechanisms and plant resilience. Additionally, melatonin can tackle the stress-induced alteration of cellular redox equilibrium by regulating the expression of redox homeostasis-related genes and proteins. The purpose of this article is to compile and summarize the scientific research pertaining to MT's effects on plants' resilience to biotic and abiotic stresses. Here, we have summarized that MT exerts a synergistic effect with other phytohormones, for instance, ethylene, jasmonic acid, and salicylic acid, and activates plant defense-related genes against phytopathogens. Furthermore, MT interacts with secondary messengers like Ca2+, nitric oxide, and reactive oxygen species to regulate the redox network. This interaction triggers different transcription factors to alleviate stress-related responses in plants. Hence, the critical synergic role of MT with diverse plant hormones and secondary messengers demonstrates phytomelatonin's importance in influencing multiple mechanisms to contribute to plant resilience against harsh environmental factors."
Authors: Soumya Mukherjee, Francisco J. Corpas.
Plant, Cell & Environment (2023)
Abstract: "Hydrogen peroxide (H2O2) is a reactive oxygen species (ROS) and a key modulator of the development and architecture of the root system under physiological and adverse environmental conditions. Nitric oxide (NO) and hydrogen sulfide (H2S) also exert myriad functions on plant development and signaling. Accumulating pieces of evidence show that depending upon the dose and mode of applications, NO and H2S can have synergistic or antagonistic actions in mediating H2O2 signaling during root development. Thus, H2O2-NO- H2S crosstalk might essentially impart tolerance to elude oxidative stress in roots. Growth and proliferation of root apex involve crucial orchestration of NO- and H2S-mediated ROS signaling which also comprise other components including mitogen-activated protein kinase, cyclins, cyclin-dependent kinases, respiratory burst oxidase homolog (RBOH), and Ca2+ flux. This assessment provides a comprehensive update on the cooperative roles of NO and H2S in modulating H2O2 homeostasis during root development, abiotic stress tolerance, and root-microbe interaction. Furthermore, it also analyses the scopes of some fascinating future investigations associated with strigolactone and karrikins concerning H2O2-NO-H2S crosstalk in plant roots."
Authors: Deepak Kumar and Puja Ohri.
Nitric Oxide (2023)
Highlights: • Various abiotic and biotic stressors adversely affect the growth, development and productivity of plants. • It becomes decisive to protect the plants from these stressors to meet the food demand of increasing population. • Nitric oxide (NO), a gaseous signaling molecule could enhance the crop production by increasing stress tolerance. • NO also interacts with other signaling molecules and may induce resistance in plants against different types of stresses.
Abstract: "Nitric oxide (NO) is a diatomic gaseous molecule, which plays different roles in different strata of organisms. Discovered as a neurotransmitter in animals, NO has now gained a significant place in plant signaling cascade. NO regulates plant growth and several developmental processes including germination, root formation, stomatal movement, maturation and defense in plants. Due to its gaseous state, it is unchallenging for NO to reach different parts of cell and counterpoise antioxidant pool. Various abiotic and biotic stresses act on plants and affect their growth and development. NO plays a pivotal role in alleviating toxic effects caused by various stressors by modulating oxidative stress, antioxidant defense mechanism, metal transport and ion homeostasis. It also modulates the activity of some transcriptional factors during stress conditions in plants. Besides its role during stress conditions, interaction of NO with other signaling molecules such as other gasotransmitters (hydrogen sulfide), phytohormones (abscisic acid, salicylic acid, jasmonic acid, gibberellin, ethylene, brassinosteroids, cytokinins and auxin), ions, polyamines, etc. has been demonstrated. These interactions play vital role in alleviating plant stress by modulating defense mechanisms in plants. Taking all these aspects into consideration, the current review focuses on the role of NO and its interaction with other signaling molecules in regulating plant growth and development, particularly under stressed conditions."
Authors: Nishat Parveen, Nidhi Kandhol, Shivesh Sharma, Vijay Pratap Singh, Devendra Kumar Chauhan, Jutta Ludwig-Müller, Francisco J. Corpas and Durgesh Kumar Tripathi.
Plant and Cell Physiology (2022)
Abstract: "The phytohormone auxin acts as an important signaling molecule having regulatory functions during the growth and development of plants. Reactive oxygen species (ROS) are also known to perform signaling functions at low concentrations, however, over-accumulation of ROS due to various environmental stresses damages the biomolecules, cell structures and lead to cell death, therefore it can be said that ROS act as a double-edged sword. Nitric oxide (NO), a gaseous signaling molecule, performs a wide range of favourable roles in plants. NO displays its positive role in photo-morphogenesis, root growth, leaf expansion, seed germination, stomatal closure, senescence, fruit maturation, mitochondrial activity, and metabolism of iron. Studies have revealed the early existence of these crucial molecules during evolution. Moreover, auxin, ROS, and NO together show their involvement in various developmental processes and abiotic stress tolerance. Redox signaling is a primary response during exposure of plants to stresses and shows a link with auxin signaling. This review provides updated information related to crosstalk between auxin, ROS, and NO starting from their evolution during early earth periods and their interaction in plant growth and developmental processes as well as in the case of abiotic stresses to plants."
Authors: Jing Huang, Qi Wu, Huai Kang Jing, Ren Fang Shen and Xiao Fang Zhu.
Plant Science (2022)
Highlights • Auxin facilitates cell-wall inorganic P (Pi) reutilization in Pi-deficient rice. • The Pi is reutilized in an NO-ethylene-dependent manner. • Auxin accelerates translocation of Pi from root to shoot. • Translocation of Pi is accelerated by elevating the transcript level of OsPT2.
Abstract: "Auxin is involved in stress responses of plants, such as phosphorus (P) deficiency in rice. Studies on whether auxin participates in cell-wall inorganic phosphorous (Pi) reutilization in Pi-starved rice are scarce. This study explored the mechanisms underlying auxin-facilitated cell-wall Pi-reutilization in rice roots. Pi deficiency rapidly induced auxin accumulation in roots; exogenous auxin [α-naphthaleneacetic acid (NAA), a permeable analog of auxin] elevated soluble Pi content in roots and shoots by increasing pectin content by enhancing activity of pectin methylesterase, and upregulating the transcript level of PHOSPHORUS-TRANSPORTER-2, such that more Pi was translocated to the shoot. Irrespective of the Pi status, exogenous auxin induced nitric oxide (NO) and ethylene production, while exogenous sodium nitroprusside (an NO donor) and 1-aminocyclopropane-1-carboxylic acid (a precursor of ethylene) had no effect on auxin content, suggesting that auxin may act upstream of NO and ethylene. The beneficial effect of NAA in increasing soluble Pi content in roots and shoots disappeared when 2-(4-carboxyphenyl)− 4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (a scavenger of NO) or aminoethoxyvinylglycine (an inhibitor of ethylene) were applied, suggesting that auxin facilitates cell-wall Pi-reutilization in a NO-ethylene-dependent manner in Pi-deficient rice. Our study results suggest auxin application as an effective agronomic practice for improving plant Pi nutrition in P-deficient conditions."
Authors: Seung Yong Shin, Su-Jin Park, Hyun-Soon Kim, Jae-Heung Jeon and Hyo-Jun Lee.
BMC Plant Biology (2022)
Abstract: "Background - Reactive oxygen species (ROS) and calcium ions (Ca2+) are representative signals of plant wound responses. Wounding triggers cell fate transition in detached plant tissues and induces de novo root organogenesis. While the hormonal regulation of root organogenesis has been widely studied, the role of early wound signals including ROS and Ca2+ remains largely unknown. Results - We identified that ROS and Ca2+ are required for de novo root organogenesis, but have different functions in Arabidopsis explants. The inhibition of the ROS and Ca2+ signals delayed root development in detached leaves. Examination of the auxin signaling pathways indicated that ROS and Ca2+ did not affect auxin biosynthesis and transport in explants. Additionally, the expression of key genes related to auxin signals during root organogenesis was not significantly affected by the inhibition of ROS and Ca2+ signals. The addition of auxin partially restored the suppression of root development by the ROS inhibitor; however, auxin supplementation did not affect root organogenesis in Ca2+-depleted explants. Conclusions - Our results indicate that, while both ROS and Ca2+ are key molecules, at least in part of the auxin signals acts downstream of ROS signaling, and Ca2+ acts downstream of auxin during de novo root organogenesis in leaf explants."
Authors: S. Pols, B. Van de Poel, M.L.A.T.M. Hertog and B.M. Nicolaï.
Postharvest Biology and Technology (2022)
Highlights: • The role of NO in mediating biotic and abiotic plant stresses is highly complex. • Understanding NO-ethylene crosstalk is essential to low oxygen storage. • The postharvest potential of NO is still largely unexploited.
Abstract: "Nitric oxide (NO), a highly reactive small gaseous molecule, has received increasing attention over the past forty years. First studied and analysed as an air pollutant, it was later identified as an important signalling molecule in living organisms. While being a cardinal part of mammalian neurotransmission and respiratory energy production, much of the molecular mechanism underlying NO homeostasis in plants remains unclear. When considering the physiological function of NO during fruit ripening and postharvest storage, the signalling pathways and regulatory mechanisms are even more poorly understood. In this frontiers article, a comprehensive overview of NO synthesis and signalling is provided, introducing to the reader to the complex regulatory mechanisms NO influences. We continue to explore the diverse roles nitric oxide plays in mediating both plant biotic and abiotic stresses, including its intricate relationship with various plant hormones. Special attention goes to the significance of stress mediation by NO for the postharvest industry. Especially the recent implication of nitric oxide - ethylene crosstalk during hypoxia stress, is of particular relevance for controlled atmosphere storage of fresh produce. An overview of the current uses and applications of NO in a postharvest context is also provided, highlighting the difficulties surrounding commercial application of NO. This review is concluded by identifying the main critical questions and research gaps on NO in a postharvest context."
Authors: Yinglin Ji, Mingyang Xu, Zhi Liu, Hui Yuan, Tianxing Lv, Hongjian Li, Yaxiu Xu, Yajing Si and Aide Wang.
New Phytologist (2022)
Abstract: "Nitric oxide (NO) is known to modulate the action of several phytohormones. This includes the gaseous hormone ethylene, but the molecular mechanisms underlying the effect of NO on ethylene biosynthesis are unclear. Here, we observed a decrease in endogenous NO abundance during apple (Malus domestica) fruit development and exogenous treatment of apple fruit with a NO donor suppressed ethylene production, suggesting that NO is a ripening suppressor. Expression of the transcription factor MdERF5 was activated by NO donor treatment. NO induced the nucleocytoplasmic shuttling of MdERF5 by modulating its interaction with the protein phosphatase, MdPP2C57. MdPP2C57 induced dephosphorylation of MdERF5 at Ser260 is sufficient to promote nuclear export of MdERF5. As a consequence of this export, MdERF5 proteins in the cytoplasm interacted with and suppressed the activity of MdACO1, an enzyme that converts 1-aminocyclopropane-1-carboxylic acid (ACC) to ethylene. The NO-activated MdERF5 was observed to increase in abundance in the nucleus and bind to the promoter of the ACC synthase gene MdACS1 and directly suppress its transcription."
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Authors: Chiara Pucciariello and Pierdomenico Perata.
Journal of Experimental Botany (2024)
Abstract: "Plant quiescence and seed dormancy can be triggered by reduced oxygen availability. Under water, oxygen depletion caused by flooding can culminate in a quiescent state, which is a plant strategy for energy preservation and survival. In adult plants, a quiescent state can be activated by sugar starvation, culminating in metabolic depression. In seeds, secondary dormancy can be activated by reduced oxygen availability, which creates an unfavourable state for germination. The physical dormancy of some seeds and buds includes barriers to external conditions, which indirectly results in hypoxia. The molecular processes that support seed dormancy and plant survival through quiescence under hypoxia include the N-degron pathway, which enables the modulation of ethylene responsive factors of group VII and downstream targets. This oxygen- and nitric oxide-dependent mechanism interacts with phytohormone-related pathways to control growth."
Authors: Felix Lutter, Wolfram Brenner, Franziska Krajinski-Barth and Vajiheh Safavi-Rizi.
Plant Signaling & Behavior (2024)
Abstract: "Nitric oxide (NO) and cytokinins (CKs) are known for their crucial contributions to plant development, growth, senescence, and stress response. Despite the importance of both signals in stress responses, their interaction remains largely unexplored. The interplay between NO and CKs emerges as particularly significant not only regarding plant growth and development but also in addressing plant stress response, particularly in the context of extreme weather events leading to yield loss. In this review, we summarize NO and CKs metabolism and signaling. Additionally, we emphasize the crosstalk between NO and CKs, underscoring its potential impact on stress response, with a focus on hypoxia tolerance. Finally, we address the most urgent questions that demand answers and offer recommendations for future research endeavors."
Authors: Tanya Singh, Nikita Bisht, Mohd Mogees Ansari and Puneet Singh Chauhan.
Plant Physiology and Biochemistry (2024)
Highlights • Plant roots play an essential role in adapting to environmental cues. • Coordinated cellular processes are driven by ROS and plant hormones. • Bidirectional interaction of ROS and hormones shapes plant root development. • ROS-hormone interplay offers agricultural potential to enhance plant stress resilience.
Abstract: "Root system architecture, encompassing lateral roots and root hairs, plays a vital in overall plant growth and stress tolerance. Reactive oxygen species (ROS) and plant hormones intricately regulate root growth and development, serving as signaling molecules that govern processes such as cell proliferation and differentiation. Manipulating the interplay between ROS and hormones has the potential to enhance nutrient absorption, stress tolerance, and agricultural productivity. In this review, we delve into how studying these processes provides insights into how plants respond to environmental changes and optimize growth patterns to better control cellular processes and stress responses in crops. We discuss various factors and complex signaling networks that may exist among ROS and phytohormones during root development. Additionally, the review highlights possible role of reactive nitrogen species (RNS) in ROS-phytohormone interactions and in shaping root system architecture according to environmental cues."
Authors: Mohammed M. Mira, Eman A. El-Khateeb, Mohamed S. Youssef, Katarzyna Ciacka, Kenny So, Robert W. Duncan, Robert D. Hill and Claudio Stasolla.
Planta (2023)
Main conclusion: Over-expression of phytoglobin mitigates the degradation of the root apical meristem (RAM) caused by waterlogging through changes in nitric oxide and auxin distribution at the root tip.
Abstract: "Plant performance to waterlogging is ameliorated by the over-expression of the Arabidopsis Phytoglobin 1 (Pgb1) which also contributes to the maintenance of a functional RAM. Hypoxia induces accumulation of ROS and damage in roots of wild type plants; these events were preceded by the exhaustion of the RAM resulting from the loss of functionality of the WOX5-expressing quiescent cells (QCs). These phenotypic deviations were exacerbated by suppression of Pgb1 and attenuated when the same gene was up-regulated. Genetic and pharmacological studies demonstrated that degradation of the RAM in hypoxic roots is attributed to a reduction in the auxin maximum at the root tip, necessary for the specification of the QC. This reduction was primarily caused by alterations in PIN-mediated auxin flow but not auxin synthesis. The expression and localization patterns of several PINs, including PIN1, 2, 3 and 4, facilitating the basipetal translocation of auxin and its distribution at the root tip, were altered in hypoxic WT and Pgb1-suppressing roots but mostly unchanged in those over-expressing Pgb1. Disruption of PIN1 and PIN2 signal in hypoxic roots suppressing Pgb1 initiated in the transition zone at 12 h and was specifically associated to the absence of Pgb1 protein in the same region. Exogenous auxin restored a functional RAM, while inhibition of the directional auxin flow exacerbated the degradation of the RAM. The regulation of root behavior by Pgb1 was mediated by nitric oxide (NO) in a model consistent with the recognized function of Pgbs as NO scavengers. Collectively, this study contributes to our understanding of the role of Pgbs in preserving root meristem function and QC niche during conditions of stress, and suggests that the root transition zone is most vulnerable to hypoxia.
Authors: Yuriy E. Kolupaev, Tetiana O. Yastreb and Alexander P. Dmitriev.
Plants (2023)
Abstract: "Plant cells respond to stress by activating signaling and regulatory networks that include plant hormones and numerous mediators of non-hormonal nature. These include the universal intracellular messenger calcium, reactive oxygen species (ROS), gasotransmitters, small gaseous molecules synthesized by living organisms, and signal functions such as nitrogen monoxide (NO), hydrogen sulfide (H2S), carbon monoxide (CO), and others. This review focuses on the role of functional linkages of jasmonic acid and jasmonate signaling components with gasotransmitters and other signaling mediators, as well as some stress metabolites, in the regulation of plant adaptive responses to abiotic stressors. Data on the involvement of NO, H2S, and CO in the regulation of jasmonic acid formation in plant cells and its signal transduction were analyzed. The possible involvement of the protein components of jasmonate signaling in stress-protective gasotransmitter effects is discussed. Emphasis is placed on the significance of the functional interaction between jasmonic acid and signaling mediators in the regulation of the antioxidant system, stomatal apparatus, and other processes important for plant adaptation to abiotic stresses."
Authors: Hongwei Jing, Xiaolu Yang, Ryan J. Emenecker, Jian Feng, Jian Zhang, Marcelo Rodrigues Alves de Figueiredo, Patarasuda Chaisupa, R. Clay Wright, Alex S. Holehouse, Lucia C. Strader and Jianru Zuo.
Journal of Genetics and Genomics (2023)
Abstract: "The phytohormone auxin plays crucial roles in nearly every aspect of plant growth and development. Auxin signaling is activated through the phytohormone-induced proteasomal degradation of the Auxin/INDOLE-3-ACETIC ACID (Aux/IAA) family of transcriptional repressors. Notably, many auxin-modulated physiological processes are also regulated by nitric oxide (NO) that executes its biological effects predominantly through protein S-nitrosylation at specific cysteine residues. However, little is known about the molecular mechanisms in regulating the interactive NO and auxin networks. Here, we show that NO represses auxin signaling by inhibiting IAA17 protein degradation. NO induces the S-nitrosylation of Cys-70 located in the intrinsically disordered region of IAA17, which inhibits the TIR1-IAA17 interaction and consequently the proteasomal degradation of IAA17. The accumulation of a higher level of IAA17 attenuates auxin response. Moreover, an IAA17C70W nitrosomimetic mutation renders the accumulation of a higher level of the mutated protein, thereby causing partial resistance to auxin and defective lateral root development. Taken together, these results suggest that S-nitrosylation of IAA17 at Cys-70 inhibits its interaction with TIR1, thereby negatively regulating auxin signaling. This study provides unique molecular insights into the redox-based auxin signaling in regulating plant growth and development."
Authors: Alvaro Sanchez-Corrionero, Inmaculada Sánchez-Vicente, Noelia Arteaga, Isabel Manrique-Gil, Sara Gómez-Jiménez, Isabel Torres-Quezada, Pablo Albertos and Oscar Lorenzo.
Journal of Experimental Botany (2023)
Abstract: "Plant root growth and developmental capacities reside in a few stem cells of the root apical meristem (RAM). Maintenance of these stem cells requires regenerative divisions of the initial stem cell niche (SCN) cells, self-maintenance, and proliferative divisions of the daughter cells. This ensures sufficient cell diversity to guarantee the development of complex root tissues in the plant. Damage in the root during growth involves the formation of a new post-embryonic root, a process known as regeneration. Post-embryonic root development and organogenesis processes include primary root (PR) development and SCN maintenance, plant regeneration and the development of adventitious and lateral roots. These developmental processes require a fine-tuned balance between cell proliferation and maintenance. An important regulator during root development and regeneration is the gasotransmitter nitric oxide (NO). In this review we have sought to compile how NO regulates cell rate proliferation, cell differentiation, and quiescence of SCNs, usually through interaction with phytohormones, or other molecular mechanisms involved in cellular redox homeostasis. NO exerts a role on molecular components of the auxin (Aux) and cytokinin (CK) signaling pathways in PR that affects cell proliferation and maintenance of the RAM. During root regeneration, a peak of Aux and CKs triggers specific molecular programs. Moreover, NO participates in adventitious root formation through its interaction with players of the brassinosteroids (BRs) and CKs signaling cascade. Lately, NO has been implicated in root regeneration under hypoxia conditions by regulating stem cell specification through phytoglobins."
Authors: Katarzyna Ciacka, Pawel Staszek, Katarzyna Sobczynska, Urszula Krasuska and Agnieszka Gniazdowska.
Frontiers in Plant Science (2022)
Abstract: "Nitric oxide (NO) has been recognized as a gasotransmitter in the mainstream of plant research since the beginning of the 21st century. It is produced in plant tissue and the environment. It influences plant physiology during every ontogenetic stage from seed germination to plant senescence. In this review, we demonstrate the increased interest in NO as a regulatory molecule in combination with other signalling molecules and phytohormones in the information network of plant cells. This work is a summary of the current knowledge on NO action in seeds, starting from seed pretreatment techniques applied to increase seed quality. We describe mode of action of NO in the regulation of seed dormancy, germination, and aging. During each stage of seed physiology, NO appears to act as a key agent with a predominantly beneficial effect."
Authors: Hongwei Jing, Xiaolu Yang, Jian Feng, Jian Zhang, Lucia Strader and Jianru Zuo.
bioRxiv (2022)
Abstract: "Auxin plays crucial roles in nearly every aspect of plant growth and development. Auxin signaling activation is mediated through degradation of Auxin/INDOLE-3-ACETIC ACID (Aux/IAA) family. Nitric oxide (NO) regulates diverse cellular bioactivities through S-nitrosylation of target protein at specific cysteine residues. NO-auxin interplay has an important role in regulation plant growth. However, little is known about the molecular mechanism of how NO effects Aux/IAA proteins stability. Here we show that NO negatively regulates the IAA17 protein stability to repress auxin signaling. We found that NO directly inhibits IAA17 protein degradation. S-nitrosylation of IAA17 at Cys-70 represses the TIR-IAA17 co-receptor interaction to attenuate auxin responsiveness. Our data suggest a model in which S-nitrosylation of IAA17 at Cys-70 negatively regulates auxin signaling to effect plant development, providing a mechanism for redox-phytohormones networks."
Authors: Le Luo, Yuanming Xie and Wei Xuan.
Journal of Experimental Botany (2022)
Abstract: "Plant lateral roots (LRs) initiate when a small group of pericycle cells are primed to undergo cell division to form LR primordia (LRPs). This process involves a complex gene regulatory network. In Arabidopsis, an auxin-dependent AUX/IAA14/28–ARF7/19–GATA23/LBD16 signaling cascade is known to control the LR initiation. However, it is largely unknown how auxin signaling is regulated. In this issue,Li et al. (2022) identified prohibitin 3 (PHB3) as a regulator of LR initiation in Arabidopsis. PHB3 affects the accumulation of endogenous nitric oxide (NO), which leads to the degradation of IAA14 and IAA28, thereby inducing the expression of GATA23 and LBD16 to activate LR initiation."
Authors: Shuna Li, Qingqing Li, Xiao Tian, Lijun Mu, Meiling Ji, Xiaoping Wang, Na Li, Fei Liu, Jing Shu, Nigel M. Crawford and Yong Wang.
Journal of Experimental Botany (2022)
Abstract: "We previously showed that PHB3 regulates auxin-stimulated lateral root (LR) formation; however, the underlying molecular mechanism is unknown. Here, we demonstrate that PHB3 regulates LR development mainly through influencing lateral root primordia (LRP) initiation via affecting nitric oxide (NO) accumulation. The reduced LRP in phb3 was largely rescued by exogenous NO donor SNAP treatment. The decreased NO accumulation in phb3 caused a lower expression of GATA23 and LBD16 through inhibiting the degradation of IAA14/28. Overexpression of either GATA23 or LBD16 in phb3 mutant background recovered the reduced LRP number phenotype. These results indicate that PHB3 regulates LRP initiation via NO-mediated auxin signaling through regulating the degradation of IAA14/28."
Authors: Lichao Chen, Shuhao Sun, Chun-Peng Song, Jian-Min Zhou, Jiayang Li and Jianru Zuo.
Journal of Genetics and Genomics (2022)
Abstract: "In response to dynamically altered environments, plants must finely coordinate the balance between growth and stress responses for their survival. However, the underpinning regulatory mechanisms remain largely elusive. The phytohormone gibberellin promotes growth via a derepression mechanism by proteasomal degradation of the DELLA transcription repressors. Conversely, the stress-induced burst of nitric oxide (NO) enhances stress tolerance, largely relaying on NO-mediated S-nitrosylation, a redox-based posttranslational modification. Here, we show that S-nitrosylation of Cys-374 in the Arabidopsis RGA protein, a key member of DELLAs, inhibits its interaction with the F-box protein SLY1, thereby preventing its proteasomal degradation under salinity condition. The accumulation of RGA consequently retards growth but enhances salt tolerance. We propose that NO negatively regulates gibberellin signaling via S-nitrosylation of RGA to coordinate the balance of growth and stress responses when challenged by adverse environments."
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