Special Issue: Cell signaling   

September 2018, Volume 60 Issue 9, Pages 741-906.


Cover Caption: Cell signaling
Endomembrane trafficking is important for brassinosteroid receptor©\mediated signal transduction. In this issue, Claus et al. (pp. 827¨C840) summarize the up©\to©\date knowledge underlying the endocytosis of different plant plasma membrane receptors. The impact of endomembrane trafficking on the signaling outputs in plant development and immunity is also discussed.

 

          Editorial
Cell signaling leads the way  
Author: Jia Li
Journal of Integrative Plant Biology 2018 60(9): 743-744
Published Online: August 14, 2018
DOI: 10.1111/jipb.12707
Abstract (Browse 52)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
          Invited Expert Reviews
Cold signaling in plants: Insights into mechanisms and regulation  
Author: Xiaoyu Guo, Dongfeng Liu and Kang Chong
Journal of Integrative Plant Biology 2018 60(9): 745-756
Published Online: August 10, 2018
DOI: 10.1111/jipb.12706
      
    

To survive under cold temperatures plants must be able to perceive a cold signal and transduce it into downstream components that induce appropriate defense mechanisms. In addition to inducing adaptive defenses, such as the production of osmotic factors to prevent freezing and the reprogramming of transcriptional pathways, cold temperatures induce changes in plant growth and development which can affect the plant life cycle. In this review, we summarize recent progress in characterizing cold©\related genes and the pathways that allow transduction of the cold signal in plants, focusing primarily on studies in Arabidopsis thaliana and rice (Oryza sativa). We summarize cold perception and signal transduction from the plasma membrane to the nucleus, which involves cold sensors, calcium signals, calcium©\binding proteins, mitogen©\activated protein kinase cascades, and the C©\repeat binding factor/dehydration©\responsive element binding pathways, as well as trehalose metabolism. Finally, we describe the balance between plant organogenesis and cold tolerance mechanisms in rice. This review encapsulates the known cold signaling factors in plants and provides perspectives for ongoing cold signaling research.

Abstract (Browse 51)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Cold temperature is sensed by plant to modify the patterns of growth and development. Cold signal sensing and transduction are immediately responded at molecular level in plant cells. In this review, we summarize the recent progresses in regard to cold©\related genes and elucidate the cold signal transduction pathways in plants, by primarily focusing on the studies in Arabidopsis thaliana and rice (Oryza sativa).
Molecular mechanisms governing plant responses to high temperatures  
Author: Bingjie Li, Kang Gao, Huimin Ren and Wenqiang Tang
Journal of Integrative Plant Biology 2018 60(9): 757-779
Published Online: July 20, 2018
DOI: 10.1111/jipb.12701
      
    

The increased prevalence of high temperatures (HTs) around the world is a major global concern, as they dramatically affect agronomic productivity. Upon HT exposure, plants sense the temperature change and initiate cellular and metabolic responses that enable them to adapt to their new environmental conditions. Decoding the mechanisms by which plants cope with HT will facilitate the development of molecular markers to enable the production of plants with improved thermotolerance. In recent decades, genetic, physiological, molecular, and biochemical studies have revealed a number of vital cellular components and processes involved in thermoresponsive growth and the acquisition of thermotolerance in plants. This review summarizes the major mechanisms involved in plant HT responses, with a special focus on recent discoveries related to plant thermosensing, heat stress signaling, and HT©\regulated gene expression networks that promote plant adaptation to elevated environmental temperatures.

Abstract (Browse 55)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Plants can sense raised environmental temperature and change cellular activities to adapt to the temperature changes. In this review, we summarize recent discoveries related to plant high temperature sensing, thermo©\responsive growth regulation, and heat shock signal transduction mechanisms in plants.
Insights into the regulation of C©\repeat binding factors in plant cold signaling  
Author: Jingyan Liu, Yiting Shi, and Shuhua Yang
Journal of Integrative Plant Biology 2018 60(9): 780-795
Published Online: April 18, 2018
DOI: 10.1111/jipb.12657
      
    

Cold temperatures, a major abiotic stress, threaten the growth and development of plants, worldwide. To cope with this adverse environmental cue, plants from temperate climates have evolved an array of sophisticated mechanisms to acclimate to cold periods, increasing their ability to tolerate freezing stress. Over the last decade, significant progress has been made in determining the molecular mechanisms underpinning cold acclimation, including following the identification of several pivotal components, including candidates for cold sensors, protein kinases, and transcription factors. With these developments, we have a better understanding of the CBF©\dependent cold©\signaling pathway. In this review, we summarize recent progress made in elucidating the cold©\signaling pathways, especially the C©\repeat binding factor©\dependent pathway, and describe the regulatory function of the crucial components of plant cold signaling. We also discuss the unsolved questions that should be the focus of future work.

Abstract (Browse 128)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Cold acclimation is an effective mechanism to defense freezing tolerance for plants. CBF transcription factors play predominant roles in plant cold acclimation and tolerance. We summarize the biological function of the CBFs in cold acclimation, and the regulation of the CBF signaling pathway at both transcriptional and post©\translational level.
Unraveling salt stress signaling in plants  
Author: Yongqing Yang and Yan Guo
Journal of Integrative Plant Biology 2018 60(9): 796-804
Published Online: June 15, 2018
DOI: 10.1111/jipb.12689
      
    

Salt stress is a major environmental factor limiting plant growth and productivity. A better understanding of the mechanisms mediating salt resistance will help researchers design ways to improve crop performance under adverse environmental conditions. Salt stress can lead to ionic stress, osmotic stress and secondary stresses, particularly oxidative stress, in plants. Therefore, to adapt to salt stress, plants rely on signals and pathways that re©\establish cellular ionic, osmotic, and reactive oxygen species (ROS) homeostasis. Over the past two decades, genetic and biochemical analyses have revealed several core stress signaling pathways that participate in salt resistance. The Salt Overly Sensitive signaling pathway plays a key role in maintaining ionic homeostasis, via extruding sodium ions into the apoplast. Mitogen©\activated protein kinase cascades mediate ionic, osmotic, and ROS homeostasis. SnRK2 (sucrose nonfermenting 1©\related protein kinase 2) proteins are involved in maintaining osmotic homeostasis. In this review, we discuss recent progress in identifying the components and pathways involved in the plant's response to salt stress and their regulatory mechanisms. We also review progress in identifying sensors involved in salt©\induced stress signaling in plants.

Abstract (Browse 104)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Salt stress is the main environmental factor limiting crop productivity. A better understanding of the mechanisms that regulate salt tolerance will help researchers design ways to improve crop performance. In this review, we discuss recent advances in determining the components of plants that respond to salt stress and their regulatory mechanisms.
Reactive oxygen species signaling and stomatal movement in plant responses to drought stress and pathogen attack  
Author: Junsheng Qi, Chun-Peng Song, Baoshan Wang, Jianmin Zhou, Jaakko Kangasjärvi, Jian-Kang Zhu and Zhizhong Gong
Journal of Integrative Plant Biology 2018 60(9): 805-826
Published Online: April 16, 2018
DOI: 10.1111/jipb.12654
      
    

Stomata, the pores formed by a pair of guard cells, are the main gateways for water transpiration and photosynthetic CO2 exchange, as well as pathogen invasion in land plants. Guard cell movement is regulated by a combination of environmental factors, including water status, light, CO2 levels and pathogen attack, as well as endogenous signals, such as abscisic acid and apoplastic reactive oxygen species (ROS). Under abiotic and biotic stress conditions, extracellular ROS are mainly produced by plasma membrane©\localized NADPH oxidases, whereas intracellular ROS are produced in multiple organelles. These ROS form a sophisticated cellular signaling network, with the accumulation of apoplastic ROS an early hallmark of stomatal movement. Here, we review recent progress in understanding the molecular mechanisms of the ROS signaling network, primarily during drought stress and pathogen attack. We summarize the roles of apoplastic ROS in regulating stomatal movement, ABA and CO2 signaling, and immunity responses. Finally, we discuss ROS accumulation and communication between organelles and cells. This information provides a conceptual framework for understanding how ROS signaling is integrated with various signaling pathways during plant responses to abiotic and biotic stress stimuli.

Abstract (Browse 183)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Stomata are the main gateways for water transpiration and photosynthetic CO2 exchange, as well as pathogen invasion in land plants. Stomatal movement is regulated by a combination of environmental factors including water status, light, CO2 levels and pathogen attack, as well as abscisic acid and apoplastic reactive oxygen species (ROS).
The crossroads of receptor©\mediated signaling and endocytosis in plants  
Author: Lucas Alves Neubus Claus, Daniel V. Savatin and Eugenia Russinova
Journal of Integrative Plant Biology 2018 60(9): 827-840
Published Online: June 7, 2018
DOI: 10.1111/jipb.12672
      
    

Plants deploy numerous plasma membrane receptors to sense and rapidly react to environmental changes. Correct localization and adequate protein levels of the cell©\surface receptors are critical for signaling activation and modulation of plant development and defense against pathogens. After ligand binding, receptors are internalized for degradation and signaling attenuation. However, one emerging notion is that the ligand©\induced endocytosis of receptor complexes is important for the signal duration, amplitude, and specificity. Recently, mutants of major endocytosis players, including clathrin and dynamin, have been shown to display defects in activation of a subset of signal transduction pathways, implying that signaling in plants might not be solely restricted to the plasma membrane. Here, we summarize the up©\to©\date knowledge of receptor complex endocytosis and its effect on the signaling outcome, in the context of plant development and immunity.

Abstract (Browse 99)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Plants deploy numerous plasma membrane receptors to sense and rapidly react to environmental changes, modulating plant development and defense responses. In this review, we summarize the up©\to©\date knowledge about receptor©\mediated endocytosis and its effect on signaling in the context of plant development and immunity.
Receptor©\like protein kinases: Key regulators controlling root hair development in Arabidopsis thaliana  
Author: Zhuoyun Wei and Jia Li
Journal of Integrative Plant Biology 2018 60(9): 841-850
Published Online: May 4, 2018
DOI: 10.1111/jipb.12663
      
    

Root hairs are tubular outgrowths specifically differentiated from epidermal cells in a differentiation zone. The formation of root hairs greatly increases the surface area of a root and maximizes its ability to absorb water and inorganic nutrients essential for plant growth and development. Root hair development is strictly regulated by intracellular and intercellular signal communications. Cell surface©\localized receptor©\like protein kinases (RLKs) have been shown to be important components in these cellular processes. In this review, the functions of a number of key RLKs in regulating Arabidopsis root hair development are discussed, especially those involved in root epidermal cell fate determination and root hair tip growth.

Abstract (Browse 117)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
The formation of root hairs greatly increases the surface area of a root and maximizes its ability to absorb water and inorganic nutrients essential for plant growth and development. Receptor©\like protein kinases (RLKs) have been discovered as important components in root hair development, which are mainly discussed in this review.
Phosphatidic acid plays key roles regulating plant development and stress responses  
Author: Hong-Yan Yao and Hong-Wei Xue
Journal of Integrative Plant Biology 2018 60(9): 851-863
Published Online: April 16, 2018
DOI: 10.1111/jipb.12655
      
    

Phospholipids, including phosphatidic acid (PA), phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylglycerol (PG), phosphatidylserine (PS) and phosphoinositides, have emerged as an important class of cellular messenger molecules in various cellular and physiological processes, of which PA attracts much attention of researchers. In addition to its effect on stimulating vesicle trafficking, many studies have demonstrated that PA plays a crucial role in various signaling pathways by binding target proteins and regulating their activity and subcellular localization. Here, we summarize the functional mechanisms and target proteins underlying PA©\mediated regulation of cellular signaling, development, hormonal responses, and stress responses in plants.

Abstract (Browse 150)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Phosphatidic acid has emerged as an important cellular messenger in various cellular and physiological processes, which functions by binding target proteins and regulating their activities and subcellular localizations. In this review, we summarize the functional mechanisms underlying PA©\mediated regulation of cellular signaling, development, hormonal responses, and stress responses in plants.
          Research Articles
Ethylene©\induced microtubule reorientation is essential for fast inhibition of root elongation in Arabidopsis  
Author: Yichuan Wang, Yusi Ji, Ying Fu and Hongwei Guo
Journal of Integrative Plant Biology 2018 60(9): 864-877
Published Online: May 12, 2018
DOI: 10.1111/jipb.12666
      
    

Microtubule reorientation is a long©\standing observation that has been implicated in regulating the inhibitory effect of ethylene on axial elongation of plant cells. However, the signaling mechanism underlying ethylene©\induced microtubule reorientation has remained elusive. Here, we reveal, by live confocal imaging and kinetic root elongation assays, that the time courses of ethylene©\induced microtubule reorientation and root elongation inhibition are highly correlated, and that microtubule reorientation is required for the full responsiveness of root elongation to ethylene treatment. Our genetic analysis demonstrated that the effect of ethylene on microtubule orientation and root elongation is mainly transduced through the canonical linear ethylene signaling pathway. By using pharmacological and genetic analyses, we demonstrate further that the TIR1/AFBs©\Aux/IAAs©\ARFs auxin signaling pathway, but not the ABP1©\ROP6©\RIC1 auxin signaling branch, is essential for ethylene©\induced microtubule reorientation and root elongation inhibition. Together, these findings offer evidence for the functional significance and elucidate the signaling mechanism for ethylene©\induced microtubule reorientation in fast root elongation inhibition in Arabidopsis.

Abstract (Browse 132)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
In this study, we reveal by a combinatorial approach the signaling mechanism and physiological significance of the long standing observation of ethylene©\induced microtubule reorientation in rapid inhibition of Arabidopsis root elongation. Particularly, we demonstrate the importance of auxin signaling module TIR1/AFBs©\Aux/IAAs©\ARF7/19, but not ABP1©\ROP6©\RIC1, for this rapid ethylene response.
A C3HC4©\type RING finger protein regulates rhizobial infection and nodule organogenesis in Lotus japonicus  
Author: Kai Cai, Jun Yin, Hongmin Chao, Yaping Ren, Liping Jin, Yangrong Cao, Deqiang Duanmu and Zhongming Zhang
Journal of Integrative Plant Biology 2018 60(9): 878-896
Published Online: July 26, 2018
DOI: 10.1111/jipb.12703
      
    

During the establishment of rhizobia©\legume symbiosis, the cytokinin receptor LHK1 (Lotus Histidine Kinase 1) is essential for nodule formation. However, the mechanism by which cytokinin signaling regulates symbiosis remains largely unknown. In this study, an LHK1©\interacting protein, LjCZF1, was identified and further characterized. LjCZF1 is a C3HC4©\type RING finger protein that is highly conserved in plants. LjCZF1 specifically interacted with LHK1 in yeast two©\hybrid, in vitro pull©\down and co©\immunoprecipitation assays conducted in tobacco. Phosphomimetic mutation of the potential threonine (T167D) phosphorylation site enhanced the interaction between LjCZF1 and LHK1, whereas phosphorylation mutation (T167A) eliminated this interaction. Transcript abundance of LjCZF1 was up©\regulated significantly after inoculation with rhizobia. The LORE1 insertion mutant and clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR©\associated protein 9©\mediated knockout mutant Lotus japonicus plants demonstrated significantly reduced number of infection threads and nodules. In contrast, plants over©\expressing LjCZF1 exhibited increased numbers of infection threads and nodules. Collectively, these data support the notion that LjCZF1 is a positive regulator of symbiotic nodulation, possibly through interaction with LHK1.

Abstract (Browse 55)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
The plant hormone cytokinin is essential for nodule formation during rhizobia©\legume symbiotic interactions. In this study, a special type of RING protein was found to physically interact with the cytokinin receptor, and involved in fine©\tuning of symbiosis for nodule organogenesis in the model legume Lotus japonicus.
          New Technology
Calcium imaging in Arabidopsis pollen cells using G©\CaMP5  
Author: Min Diao, Xiaolu Qu and Shanjin Huang
Journal of Integrative Plant Biology 2018 60(9): 897-906
Published Online: February 9, 2018
DOI: 10.1111/jipb.12642
      
    

Calcium (Ca2+) signaling has been implicated in pollen germination and pollen tube growth. To date, however, we still know very little about how exactly Ca2+ signaling links to various physiological subcellular processes during pollen germination and pollen tube growth. Given that Ca2+ signaling is tightly related to the cytosolic concentration and dynamics of Ca2+, it is vital to trace the dynamic changes in Ca2+ levels in order to decode Ca2+ signaling. Here, we demonstrate that G©\CaMP5 serves well as an indicator for monitoring cytosolic Ca2+ dynamics in pollen cells. Using this probe, we show that cytosolic Ca2+ changes dramatically during pollen germination, and, as reported previously, Ca2+ forms a tip©\focused gradient in the pollen tube and undergoes oscillation in the tip region during pollen tube growth. In particular, using G©\CaMP5 allowed us to capture the dynamic changes in the cytosolic Ca2+ concentration ([Ca2+]cyt) in pollen tubes in response to various exogenous treatments. Our data suggest that G©\CaMP5 is a suitable probe for monitoring the dynamics of [Ca2+]cyt in pollen cells.

Abstract (Browse 301)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
We identify single©\wavelength non©\ratiometric sensor G©\CaMP5 as a suitable marker for calcium imaging in pollen cells that will facilitate future studies of the regulation of calcium homeostasis in pollen cells.
 
Editorial Office, Journal of Integrative Plant Biology, Institute of Botany, CAS
No. 20 Nanxincun, Xiangshan, Beijing 100093, China
Tel: +86 10 6283 6133 Fax: +86 10 8259 2636 E-mail: jipb@ibcas.ac.cn

Copyright © 2018 by the Institute of Botany, the Chinese Academy of Sciences
Online ISSN: 1744-7909 Print ISSN: 1672-9072 CN: 11-5067/Q