scholarly journals Mediator Complex: A Pivotal Regulator of ABA Signaling Pathway and Abiotic Stress Response in Plants

2020 ◽  
Vol 21 (20) ◽  
pp. 7755
Author(s):  
Leelyn Chong ◽  
Pengcheng Guo ◽  
Yingfang Zhu

As an evolutionarily conserved multi-protein complex, the Mediator complex modulates the association between transcription factors and RNA polymerase II to precisely regulate gene transcription. Although numerous studies have shown the diverse functions of Mediator complex in plant development, flowering, hormone signaling, and biotic stress response, its roles in the Abscisic acid (ABA) signaling pathway and abiotic stress response remain largely unclear. It has been recognized that the phytohormone, ABA, plays a predominant role in regulating plant adaption to various abiotic stresses as ABA can trigger extensive changes in the transcriptome to help the plants respond to environmental stimuli. Over the past decade, the Mediator complex has been revealed to play key roles in not only regulating the ABA signaling transduction but also in the abiotic stress responses. In this review, we will summarize current knowledge of the Mediator complex in regulating the plants’ response to ABA as well as to the abiotic stresses of cold, drought and high salinity. We will particularly emphasize the involvement of multi-functional subunits of MED25, MED18, MED16, and CDK8 in response to ABA and environmental perturbation. Additionally, we will discuss potential research directions available for further deciphering the role of Mediator complex in regulating ABA and other abiotic stress responses.

Author(s):  
Nguyen Nguyen Chuong ◽  
Xuan Lan Thi Hoang ◽  
Duong Hoang Trong Nghia ◽  
Thai Ngoc Trang Dai ◽  
Van-Anh Le Thi ◽  
...  

: Plants, as sessile organisms, are susceptible to a myriad of stress factors, especially abiotic stresses. Over the course of evolution, they have developed multiple mechanisms to sense and transduce environmental stimuli for appropriate responses. Among those, phosphorylation and dephosphorylation, regulated by protein kinases and protein phosphatases, respectively, are considered as crucial signal transduction mechanisms. Regarding the latter group, protein phosphatases type 2C (PP2Cs) represent the largest division of PPs. In addition, discovery of regulatory functions of PP2Cs in abscisic acid (ABA)-signaling pathway, the major signal transduction pathway in abiotic stress responses, indicates significant importance of PP2C members in plant adaptation to adverse environmental factors. In this review, current understanding of the roles of PP2Cs in different phytohormone-dependent pathways related to abiotic stress is summarized, highlighting the crosstalk between the ABA-signaling pathway with other hormonal pathways via certain ABA-related PP2Cs. We also updated progress of in planta characterization studies of PP2Cs under abiotic stress conditions, providing knowledge of PP2C manipulation in developing abiotic stress-tolerant crops.


2020 ◽  
Vol 21 (21) ◽  
pp. 8401
Author(s):  
Joram Kiriga Waititu ◽  
Chunyi Zhang ◽  
Jun Liu ◽  
Huan Wang

As sessile species, plants have to deal with the rapidly changing environment. In response to these environmental conditions, plants employ a plethora of response mechanisms that provide broad phenotypic plasticity to allow the fine-tuning of the external cues related reactions. Molecular biology has been transformed by the major breakthroughs in high-throughput transcriptome sequencing and expression analysis using next-generation sequencing (NGS) technologies. These innovations have provided substantial progress in the identification of genomic regions as well as underlying basis influencing transcriptional and post-transcriptional regulation of abiotic stress response. Non-coding RNAs (ncRNAs), particularly microRNAs (miRNAs), short interfering RNAs (siRNAs), and long non-coding RNAs (lncRNAs), have emerged as essential regulators of plants abiotic stress response. However, shared traits in the biogenesis of ncRNAs and the coordinated cross-talk among ncRNAs mechanisms contribute to the complexity of these molecules and might play an essential part in regulating stress responses. Herein, we highlight the current knowledge of plant microRNAs, siRNAs, and lncRNAs, focusing on their origin, biogenesis, modes of action, and fundamental roles in plant response to abiotic stresses.


2021 ◽  
Vol 22 (15) ◽  
pp. 7915
Author(s):  
Tae-Houn Kim ◽  
Eun-Joo Park

Plants have evolutionarily established resistance responses to a variety of abiotic stress conditions, in which ABA mediates the integrated regulation of these stress responses. Numerous proteins function at the transcription level or at the protein level when contributing to controls of the ABA signaling process. Although osmotin is identified as a salt-inducible protein, its function in the abiotic stress response is yet to be elucidated. To examine the role of Arabidopsis OSMOTIN 34 (OSM34) in the ABA signaling pathway, a deletion mutant osm34 generated by a CRISPR/Cas9 system and the double mutant osm34 osml (osmotin 34-like) were analyzed for various ABA responses. Both osm34 and osm34 osml showed reduced levels of ABA responses in seeds and leaves. Moreover, proline level and expression of the proline biosynthesis gene P5CS1 was significantly reduced in osm34 osml. Interestingly, OSM34 binds to SKP2A, an F-Box protein whose transcription is induced by ABA. The protein stability of OSM34 was determined to be under the control of the 26S proteasome. In conclusion, our data suggest that OSM34 functions as a positive regulator in the generation of ABA responses and is under post-translational control.


Author(s):  
Geoffrey Onaga ◽  
Kerstin Wydra

Abstract This chapter provides an overview of the recent significant perspectives on molecules involved in response and tolerance to drought and salinity, the 2 major abiotic stresses affecting crop production, and highlights major molecular components identified in major cereals.


BMC Genomics ◽  
2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Mohammad Aslam ◽  
Bello Hassan Jakada ◽  
Beenish Fakher ◽  
Joseph G. Greaves ◽  
Xiaoping Niu ◽  
...  

Abstract Background Transcription factors (TFs) are essential regulators of growth and development in eukaryotes. Basic-helix-loop-helix (bHLHs) is one of the most significant TFs families involved in several critical regulatory functions. Cryptochrome-interacting bHLH (CIB) and cryptochromes form an extensive regulatory network to mediate a plethora of pathways. Although bHLHs regulate critical biological processes in plants, the information about pineapple bHLHs remains unexplored. Results Here, we identified a total of 121 bHLH proteins in the pineapple genome. The identified genes were renamed based on the ascending order of their gene ID and classified into 18 subgroups by phylogenetic analysis. We found that bHLH genes are expressed in different organs and stages of pineapple development. Furthermore, by the ectopic expression of AcCIB2 in Arabidopsis and complementation of Atcib2 mutant, we verified the involvement of AcCIB2 in photomorphogenesis and abiotic stress response. Conclusions Our findings revealed that AcCIB2 plays an essential role in flowering time regulation and abiotic stress response. The present study provides additional insights into the current knowledge of bHLH genes and suggests their potential role in various biological processes during pineapple development.


2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Hongying Zhang ◽  
Xudong Ma ◽  
Wenjiao Li ◽  
Dexin Niu ◽  
Zhaojun Wang ◽  
...  

Abstract Background The plant-specific homeodomain-leucine zipper class IV (HD-ZIP IV) gene family has been involved in the regulation of epidermal development. Results Fifteen genes coding for HD-ZIP IV proteins were identified (NtHD-ZIP-IV-1 to NtHD-ZIP-IV-15) based on the genome of N. tabacum. Four major domains (HD, ZIP, SAD and START) were present in these proteins. Tissue expression pattern analysis indicated that NtHD-ZIP-IV-1, − 2, − 3, − 10, and − 12 may be associated with trichome development; NtHD-ZIP-IV-8 was expressed only in cotyledons; NtHD-ZIP-IV-9 only in the leaf and stem epidermis; NtHD-ZIP-IV-11 only in leaves; and NtHD-ZIP-IV-15 only in the root and stem epidermis. We found that jasmonates may induce the generation of glandular trichomes, and that NtHD-ZIP-IV-1, − 2, − 5, and − 7 were response to MeJA treatment. Dynamic expression under abiotic stress and after application of phytohormones indicated that most NtHD-ZIP IV genes were induced by heat, cold, salt and drought. Furthermore, most of these genes were induced by gibberellic acid, 6-benzylaminopurine, and salicylic acid, but were inhibited by abscisic acid. NtHD-ZIP IV genes were sensitive to heat, but insensitive to osmotic stress. Conclusion NtHD-ZIP IV genes are implicated in a complex regulatory gene network controlling epidermal development and abiotic stress responses. The present study provides evidence to elucidate the gene functions of NtHD-ZIP IVs during epidermal development and stress response.


2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Carina Steliana Carianopol ◽  
Aaron Lorheed Chan ◽  
Shaowei Dong ◽  
Nicholas J. Provart ◽  
Shelley Lumba ◽  
...  

AbstractYeast Snf1 (Sucrose non-fermenting1), mammalian AMPK (5′ AMP-activated protein kinase) and plant SnRK1 (Snf1-Related Kinase1) are conserved heterotrimeric kinase complexes that re-establish energy homeostasis following stress. The hormone abscisic acid (ABA) plays a crucial role in plant stress response. Activation of SnRK1 or ABA signaling results in overlapping transcriptional changes, suggesting these stress pathways share common targets. To investigate how SnRK1 and ABA interact during stress response in Arabidopsis thaliana, we screened the SnRK1 complex by yeast two-hybrid against a library of proteins encoded by 258 ABA-regulated genes. Here, we identify 125 SnRK1- interacting proteins (SnIPs). Network analysis indicates that a subset of SnIPs form signaling modules in response to abiotic stress. Functional studies show the involvement of SnRK1 and select SnIPs in abiotic stress responses. This targeted study uncovers the largest set of SnRK1 interactors, which can be used to further characterize SnRK1 role in plant survival under stress.


2020 ◽  
Vol 22 (1) ◽  
pp. 354
Author(s):  
Leelyn Chong ◽  
Xiaoning Shi ◽  
Yingfang Zhu

Environmental stresses have driven plants to develop various mechanisms to acclimate in adverse conditions. Extensive studies have demonstrated that a significant reprogramming occurs in the plant transcriptome in response to biotic and abiotic stresses. The highly conserved and large multi-subunit transcriptional co-activator of eukaryotes, known as the Mediator, has been reported to play a substantial role in the regulation of important genes that help plants respond to environmental perturbances. CDK8 module is a relatively new component of the Mediator complex that has been shown to contribute to plants’ defense, development, and stress responses. Previous studies reported that CDK8 module predominantly acts as a transcriptional repressor in eukaryotic cells by reversibly associating with core Mediator. However, growing evidence has demonstrated that depending on the type of biotic and abiotic stress, the CDK8 module may perform a contrasting regulatory role. This review will summarize the current knowledge of CDK8 module as well as other previously documented Mediator subunits in plant cell signaling under stress conditions.


PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10785
Author(s):  
Xue Yong ◽  
Tangchun Zheng ◽  
Xiaokang Zhuo ◽  
Sagheer Ahmad ◽  
Lulu Li ◽  
...  

Rosaceae is an important family containing some of the highly evolved fruit and ornamental plants. Abiotic stress responses play key roles in the seasonal growth and development of plants. However, the molecular basis of stress responses remains largely unknown in Rosaceae. Abscisic acid (ABA) is a stress hormone involving abiotic stress response pathways. The ABRE-binding factor/ABA-responsive element-binding protein (ABF/AREB) is a subfamily of the basic domain/leucine zipper (bZIP) transcription factor family. It plays an important role in the ABA-mediated signaling pathway. Here, we analyzed the ABF/AREB subfamily genes in nine Rosaceae species. A total of 64 ABF/AREB genes were identified, including 18, 28, and 18 genes in the Rosoideae, Amygdaloideae, and Maloideae traditional subfamilies, respectively. The evolutionary relationship of the ABF/AREB subfamily genes was studied through the phylogenetic analysis, the gene structure and conserved motif composition, Ka/Ks values, and interspecies colinearity. These gene sets were clustered into four groups. In the Prunus ABF/AREB (PmABF) promoters, several cis-elements related to light, hormone, and abiotic stress response were predicted. PmABFs expressed in five different tissues, except PmABF5, which expressed only in buds. In the dormancy stages, PmABF1, 2, 5 and 7 showed differential expression. The expression of PmABF3, 4 and 6 was positively correlated with the ABA concentration. Except for PmABF5, all the PmABFs were sensitive to ABA. Several ABRE elements were contained in the promoters of PmABF1, 3, 6, 7. Based on the findings of our study, we speculate that PmABFs may play a role in flower bud dormancy in P. mume.


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