scholarly journals Functional Characterization of a Putative RNA Demethylase ALKBH6 in Arabidopsis Growth and Abiotic Stress Responses

2020 ◽  
Vol 21 (18) ◽  
pp. 6707
Author(s):  
Trinh Thi Huong ◽  
Le Nguyen Tieu Ngoc ◽  
Hunseung Kang

RNA methylation and demethylation, which is mediated by RNA methyltransferases (referred to as “writers”) and demethylases (referred to as “erasers”), respectively, are emerging as a key regulatory process in plant development and stress responses. Although several studies have shown that AlkB homolog (ALKBH) proteins are potential RNA demethylases, the function of most ALKBHs is yet to be determined. The Arabidopsis thaliana genome contains thirteen genes encoding ALKBH proteins, the functions of which are largely unknown. In this study, we characterized the function of a potential eraser protein, ALKBH6 (At4g20350), during seed germination and seedling growth in Arabidopsis under abiotic stresses. The seeds of T-DNA insertion alkbh6 knockdown mutants germinated faster than the wild-type seeds under cold, salt, or abscisic acid (ABA) treatment conditions but not under dehydration stress conditions. Although no differences in seedling and root growth were observed between the alkbh6 mutant and wild-type under normal conditions, the alkbh6 mutant showed a much lower survival rate than the wild-type under salt, drought, or heat stress. Cotyledon greening of the alkbh6 mutants was much higher than that of the wild-type upon ABA application. Moreover, the transcript levels of ABA signaling-related genes, including ABI3 and ABI4, were down-regulated in the alkbh6 mutant compared to wild-type plants. Importantly, the ALKBH6 protein had an ability to bind to both m6A-labeled and m5C-labeled RNAs. Collectively, these results indicate that the potential eraser ALKBH6 plays important roles in seed germination, seedling growth, and survival of Arabidopsis under abiotic stresses.

2020 ◽  
Vol 21 (3) ◽  
pp. 931
Author(s):  
Ya Xu ◽  
Lu Liu ◽  
Pan Zhao ◽  
Jing Tong ◽  
Naiqin Zhong ◽  
...  

In eukaryotic cells, nucleocytoplasmic trafficking of macromolecules is largely mediated by Karyopherin β/Importin (KPNβ or Impβ) nuclear transport factors, and they import and export cargo proteins or RNAs via the nuclear pores across the nuclear envelope, consequently effecting the cellular signal cascades in response to pathogen attack and environmental cues. Although achievements on understanding the roles of several KPNβs have been obtained from model plant Arabidopsis thaliana, comprehensive analysis of potato KPNβ gene family is yet to be elucidated. In our genome-wide identifications, a total of 13 StKPNβ (Solanum tuberosum KPNβ) genes were found in the genome of the doubled monoploid S. tuberosum Group Phureja DM1-3. Sequence alignment and conserved domain analysis suggested the presence of importin-β N-terminal domain (IBN_N, PF08310) or Exporin1-like domain (XpoI, PF08389) at N-terminus and HEAT motif at the C-terminal portion in most StKPNβs. Phylogenetic analysis indicated that members of StKPNβ could be classified into 16 subgroups in accordance with their homology to human KPNβs, which was also supported by exon-intron structure, consensus motifs, and domain compositions. RNA-Seq analysis and quantitative real-time PCR experiments revealed that, except StKPNβ3d and StKPNβ4, almost all StKPNβs were ubiquitously expressed in all tissues analyzed, whereas transcriptional levels of several StKPNβs were increased upon biotic/abiotic stress or phytohormone treatments, reflecting their potential roles in plant growth, development or stress responses. Furthermore, we demonstrated that silencing of StKPNβ3a, a SA- and H2O2-inducible KPNβ genes led to increased susceptibility to environmental challenges, implying its crucial roles in plant adaption to abiotic stresses. Overall, our results provide molecular insights into StKPNβ gene family, which will serve as a strong foundation for further functional characterization and will facilitate potato breeding programs.


2021 ◽  
Vol 12 ◽  
Author(s):  
Huiqing Xia ◽  
Linlin Chen ◽  
Zhuo Fan ◽  
Mengya Peng ◽  
Jingya Zhao ◽  
...  

Heat shock protein Hsp104, a homolog of the bacterial chaperone ClpB and plant Hsp100, plays an essential part in the response to heat and various chemical agents in Saccharomyces cerevisiae. However, their functions remain largely unknown in plant fungal pathogens. Here, we report the identification and functional characterization of a plausible ortholog of yeast Hsp104 in Fusarium pseudograminearum, which we termed FpHsp104. Deletion mutant of FpHsp104 displayed severe defects in the resistance of heat shock during F. pseudograminearum mycelia and conidia when exposed to extreme heat. We also found that the protein showed dynamic localization to small particles under high temperature. However, no significant differences were detected in osmotic, oxidative, or cell wall stress responses between the wild-type and Δfphsp104 strains. Quantitative real-time PCR analysis showed that FpHsp104 was upregulated in the conidia, and disruption of FpHsp104 gene resulted in defects in conidia production, morphology, and germination. The transcript levels of conidiation-related genes of FpFluG, FpVosA, FpWetA, and FpAbaA were reduced in the Δfphsp104 mutant vs. the wild-type strain, but heat-shocked mRNA splicing repair was not affected in Δfphsp104. Moreover, Δfphsp104 mutant also showed attenuated virulence, but its DON synthesis was normal. These data from the first study of Hsp104 in F. pseudograminearum strongly suggest that FpHsp104 gene is an important element in the heat tolerance, development, and pathogenicity processes of F. pseudograminearum.


2021 ◽  
Vol 22 (2) ◽  
pp. 682
Author(s):  
Hymavathi Salava ◽  
Sravankumar Thula ◽  
Vijee Mohan ◽  
Rahul Kumar ◽  
Fatemeh Maghuly

Plants regularly face the changing climatic conditions that cause biotic and abiotic stress responses. The abiotic stresses are the primary constraints affecting crop yield and nutritional quality in many crop plants. The advances in genome sequencing and high-throughput approaches have enabled the researchers to use genome editing tools for the functional characterization of many genes useful for crop improvement. The present review focuses on the genome editing tools for improving many traits such as disease resistance, abiotic stress tolerance, yield, quality, and nutritional aspects of tomato. Many candidate genes conferring tolerance to abiotic stresses such as heat, cold, drought, and salinity stress have been successfully manipulated by gene modification and editing techniques such as RNA interference, insertional mutagenesis, and clustered regularly interspaced short palindromic repeat (CRISPR/Cas9). In this regard, the genome editing tools such as CRISPR/Cas9, which is a fast and efficient technology that can be exploited to explore the genetic resources for the improvement of tomato and other crop plants in terms of stress tolerance and nutritional quality. The review presents examples of gene editing responsible for conferring both biotic and abiotic stresses in tomato simultaneously. The literature on using this powerful technology to improve fruit quality, yield, and nutritional aspects in tomato is highlighted. Finally, the prospects and challenges of genome editing, public and political acceptance in tomato are discussed.


2021 ◽  
Vol 22 (16) ◽  
pp. 8625
Author(s):  
Shuangzhan Huang ◽  
Lanjuan Hu ◽  
Shihan Zhang ◽  
Mingxing Zhang ◽  
Wenzhu Jiang ◽  
...  

Plant WRKY transcription factors play crucial roles in plant growth and development, as well as plant responses to biotic and abiotic stresses. In this study, we identified and characterized a WRKY transcription factor in rice, OsWRKY50. OsWRKY50 functions as a transcriptional repressor in the nucleus. The transcription of OsWRKY50 was repressed under salt stress conditions, but activated after abscisic acid (ABA) treatment. OsWRKY50-overexpression (OsWRKY50-OX) plants displayed increased tolerance to salt stress compared to wild type and control plants. The expression of OsLEA3, OsRAB21, OsHKT1;5, and OsP5CS1 in OsWRKY50-OX were much higher than wild type and control plants under salt stress. Furthermore, OsWRKY50-OX displayed hyposensitivity to ABA-regulated seed germination and seedling establishment. The protoplast-based transient expression system and yeast hybrid assay demonstrated that OsWRKY50 directly binds to the promoter of OsNCED5, and thus further inhibits its transcription. Taken together, our results demonstrate that rice transcription repressor OsWRKY50 mediates ABA-dependent seed germination and seedling growth and enhances salt stress tolerance via an ABA-independent pathway.


2021 ◽  
Vol 12 ◽  
Author(s):  
Hao Zhang ◽  
Mingfang Hu ◽  
Hongyuan Ma ◽  
Li Jiang ◽  
Zhenyong Zhao ◽  
...  

The period between seed germination and seedling establishment is one of the most vulnerable stages in the life cycle of annuals in the saline environments. Although germination characteristics of Suaeda salsa seeds have been reported, the comparative germination patterns of dimorphic seeds and seedling growth to different abiotic stresses remain poorly understood. In this study, germination responses of dimorphic seeds to light and temperature were compared. Meanwhile, responses of dimorphic seeds and thereafter seedlings of S. salsa to different concentrations of NaCl and Na2SO4 were also tested. The results showed that the light did not significantly affect germination percentage of brown seeds, but significantly promoted germination of black seeds. Brown seeds could reach high germination percentage over a wide temperature range, however, germination of black seeds gradually increased with the increase of temperature. Brown seeds had higher germination percentage and velocity than black seeds under the same salt conditions. However, black seeds had higher recovery germination than brown seeds when transferred to deionized water. Young seedlings had lower salt tolerance than germinating seeds. At the same concentrations, Na2SO4 had stronger inhibitory effect on seed germination and seedling growth than NaCl. This study comprehensively compared germination traits of dimorphic seeds and seedling growth of S. salsa, and then developed a conceptual model to explain their adaptation to harsh saline environment.


2021 ◽  
Vol 22 (18) ◽  
pp. 9777
Author(s):  
Chen Feng ◽  
Yanyan Wang ◽  
Yueting Sun ◽  
Xiang Peng ◽  
Xiang Zhang ◽  
...  

Drought is the main environmental factor that limits the yield and quality of apples (Malus × domestica) grown in arid and semi-arid regions. Nuclear factor Ys (NF-Ys) are important transcription factors involved in the regulation of plant growth, development, and various stress responses. However, the function of NF-Y genes is poorly understood in apples. Here, we identified 43 NF-Y genes in the genome of apples and conducted an initial functional characterization of the apple NF-Y. Expression analysis of NF-Y members in M. sieversii revealed that a large number of NF-Ys were highly expressed in the roots compared with the leaves, and a large proportion of NF-Y genes responded to drought treatment. Furthermore, heterologous expression of MsNF-YB21, which was significantly upregulated by drought, led to a longer root length and, thus, conferred improved osmotic and salt tolerance in Arabidopsis. Moreover, the physiological analysis of MsNF-YB21 overexpression revealed enhanced antioxidant systems, including antioxidant enzymes and compatible solutes. In addition, genes encoding catalase (AtCAT2, AtCAT3), superoxide dismutase (AtFSD1, AtFSD3, AtCSD1), and peroxidase (AtPER12, AtPER42, AtPER47, AtPER51) showed upregulated expression in the MsNF-YB21 overexpression lines. These results for the MsNF-Y gene family provide useful information for future studies on NF-Ys in apples, and the functional analysis of MsNF-YB21 supports it as a potential target in the improvement of apple drought tolerance via biotechnological strategies.


2019 ◽  
Vol 20 (20) ◽  
pp. 5048 ◽  
Author(s):  
Shuzhen Li ◽  
Li Miao ◽  
Bin Huang ◽  
Lihong Gao ◽  
Chaoxing He ◽  
...  

BASIC PENTACYSTEINE (BPC) is a small transcription factor family that functions in diverse growth and development processes in plants. However, the roles of BPCs in plants, especially cucumber (Cucumis sativus L.), in response to abiotic stress and exogenous phytohormones are still unclear. Here, we identified four BPC genes in the cucumber genome, and classified them into two groups according to phylogenetic analysis. We also investigated the gene structures and detected five conserved motifs in these CsBPCs. Tissue expression pattern analysis revealed that the four CsBPCs were expressed ubiquitously in both vegetative and reproductive organs. Additionally, the transcriptional levels of the four CsBPCs were induced by various abiotic stress and hormone treatments. Overexpression of CsBPC2 in tobacco (Nicotiana tabacum) inhibited seed germination under saline, polyethylene glycol, and abscisic acid (ABA) conditions. The results suggest that the CsBPC genes may play crucial roles in cucumber growth and development, as well as responses to abiotic stresses and plant hormones. CsBPC2 overexpression in tobacco negatively affected seed germination under hyperosmotic conditions. Additionally, CsBPC2 functioned in ABA-inhibited seed germination and hypersensitivity to ABA-mediated responses. Our results provide fundamental information for further research on the biological functions of BPCs in development and abiotic stress responses in cucumber and other plant species.


2019 ◽  
Vol 61 (1) ◽  
pp. 118-129 ◽  
Author(s):  
Dantong Liu ◽  
Hongying Ji ◽  
Zhenle Yang

Abstract Cyperus esculentus is probably the only plant that is known to accumulate large amounts of oil in its tubers. However, the underlying metabolic mechanism and regulatory factors involved in oil synthesis of tubers are still largely unclear. In this study, one gene encoding type I diacylglycerol acyltransferase (DGAT) (CeDGAT1) and two genes encoding type II DGAT (CeDGAT2a and CeDGAT2b) from C. esculentus were identified and functionally analyzed. All three DGAT genes were found to be expressed in tuber, root and leaf tissues. CeDGAT1 is highly expressed in roots and leaves, whereas CeDGAT2b is dominantly expressed in tubers. Furthermore, the temporal expression pattern of CeDGAT2b is well coordinated with the oil accumulation in developing tubers. When each CeDGAT was heterologously expressed in triacylglycerol (TAG)-deficient mutant of Saccharomyces cerevisiae, Arabidopsis thaliana wild type or its TAG1 mutant with AtDGAT1 disruption, only CeDGAT2b showed the ability to restore TAG biosynthesis with lipid body formation in yeast mutant, enhance seed oil production of Arabidopsis wild type and rescue multiple seed phenotypes of TAG1 mutant. In addition, CeDGAT2b was shown to have a substrate preference for unsaturated fatty acids toward TAG synthesis. Taken together, our results indicated that CeDGAT2b from C. esculentus is an actively functional protein and is most likely the major contributor to tuber oil biosynthesis containing common fatty acids, in contrast to oil-rich seeds and fruits where DGAT1 plays a more central role than DGAT2 in oil production accumulating normal fatty acids, whereas DGAT2 is a primary regulator for oil synthesis rich in unusual fatty acids.


Flora ◽  
2018 ◽  
Vol 243 ◽  
pp. 45-52 ◽  
Author(s):  
S. Midhat S. Hadi ◽  
Muhammad Zaheer Ahmed ◽  
Abdul Hameed ◽  
M. Ajmal Khan ◽  
Bilquees Gul

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