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1.
Plant J ; 2019 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-31571281

RESUMO

Drought stress induces anthocyanin biosynthesis in many plant species, but the underlying molecular mechanism remains unclear. Ethylene response factors (ERFs) play key roles in plant growth and various stress responses, including affecting anthocyanin biosynthesis. Here, we characterized an ERF protein, MdERF38, which is involved in drought stress-induced anthocyanin biosynthesis. Biochemical and molecular analyses showed that MdERF38 interacted with MdMYB1, a positive modulator of anthocyanin biosynthesis, and facilitated the binding of MdMYB1 to its target genes. Therefore, MdERF38 promoted anthocyanin biosynthesis in response to drought stress. Furthermore, we found that MdBT2, a negative modulator of anthocyanin biosynthesis, decreased MdERF38-promoted anthocyanin biosynthesis by accelerating the degradation of the MdERF38 protein. In summary, our data provide a mechanism for drought stress-induced anthocyanin biosynthesis that involves dynamic modulation of MdERF38 at both transcriptional and post-translational levels.

2.
Plant Cell Physiol ; 2019 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-31550006

RESUMO

As an important environment factor, light affects plant growth and development throughout life. B-BOX (BBX) proteins play key roles in the regulation of light signaling. Although the multiple roles of BBX proteins have been extensively studied in Arabidopsis, the research in apple is much less extensive. In this study, we systematically characterized the negative role of an apple BBX protein MdBBX37 in light signaling, including inhibiting anthocyanin biosynthesis and promoting hypocotyl elongation. We found that MdBBX37 interacted with MdMYB1 and MdMYB9, two key positive regulators of anthocyanin biosynthesis, and inhibited the binding of those two proteins to their target genes and, therefore, negatively regulated anthocyanin biosynthesis. In addition, MdBBX37 directly bound to the promoter of MdHY5, a positive regulator of light signaling, and suppressed its expression, thus relieved MdHY5-mediated hypocotyl inhibition. Taken together, our investigations suggest that MdBBX37 is a negative regulator of light signaling in apple. Our study will provide reference for further study on the functions of BBX proteins in apple.

3.
Plant Sci ; 288: 110219, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31521216

RESUMO

The 14-3-3 proteins are a family of highly conserved phosphoserine-binding proteins that participate in the regulation of diverse physiological and developmental processes. In this research, twenty 14-3-3 genes in apples, which contained a highly conserved 14-3-3 domain, were identified and divided into two subgroups. Among them, MdGRF11 was further cloned and investigated. qRT-PCR analyses and GUS staining show that MdGRF11 is expressed in various organs and tissues with the highest expression levels found in the fruit. MdGRF11 was upregulated by polyethylene glycol 6000 (PEG 6000), NaCl, abscisic acid (ABA) and low temperature (4 °C) treatments. MdGRF11-overexpressing transgenic Arabidopsis and apple calli exhibited reduced sensitivity to salt and PEG 6000 treatments. Moreover, the ectopic expression of MdGRF11 improved the tolerance of transgenic tobacco to salt and drought stresses, which grew longer roots, underwent more growth, and presented higher chlorophyll levels than the wild-type control under salt and drought stress conditions. Furthermore, MdGRF11 expression remarkably reduced electrolyte leakage, malondialdehyde content levels, H2O2 and O2- accumulation under salt and drought stress conditions, which relied on the regulation of ROS-scavenging signaling to reduce oxidative damage of cells after salt and drought stress treatment. MdGRF11 also enhanced tolerance to stress by upregulating expression levels of ROS-scavenging and stress-related genes, especially improving responses to drought stress by modifying the water loss rates and stomatal aperture. Moreover, MdGRF11 could interact with MdAREB/ABF transcription factors through yeast two hybrid analyses. In conclusion, our results indicate that MdGRF11 acts as a positive regulator of salt and drought stress responses through regulating ROS scavenging and other signaling systems.

4.
BMC Plant Biol ; 19(1): 362, 2019 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-31426743

RESUMO

BACKGROUND: The MYB transcription factor family is one of the largest transcriptional factor families in plants and plays a multifaceted role in plant growth and development. However, MYB transcription factors involved in pathogen resistance in apple remain poorly understood. RESULTS: We identified a new MYB family member from apple, and named it MdMYB30. MdMYB30 was localized to the nucleus, and was highly expressed in young apple leaves. Transcription of MdMYB30 was induced by abiotic stressors, such as polyethylene glycol and abscisic acid. Scanning electron microscopy and gas chromatograph-mass spectrometry analyses demonstrated that ectopically expressing MdMYB30 in Arabidopsis changed the wax content, the number of wax crystals, and the transcription of wax-related genes. MdMYB30 bound to the MdKCS1 promoter to activate its expression and regulate wax biosynthesis. MdMYB30 also contributed to plant surface properties and increased resistance to the bacterial strain Pst DC3000. Furthermore, a virus-based transformation in apple fruits and transgenic apple calli demonstrated that MdMYB30 increased resistance to Botryosphaeria dothidea. Our findings suggest that MdMYB30 plays a vital role in the accumulation of cuticular wax and enhances disease resistance in apple. CONCLUSIONS: MdMYB30 bound to the MdKCS1 gene promoter to activate its transcription and regulate cuticular wax content and composition, which influenced the surface properties and expression of pathogenesis-related genes to resistance against pathogens. MdMYB30 appears to be a crucial element in the formation of the plant cuticle and confers apple with a tolerance to pathogens.

5.
Mol Plant Microbe Interact ; 32(10): 1391-1401, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31408392

RESUMO

Salicylic acid (SA) is closely related to disease resistance of plants. WRKY transcription factors have been linked to the growth and development of plants, especially under stress conditions. However, the regulatory mechanism of WRKY proteins involved in SA production and disease resistance in apple is not clear. In this study, MdPBS3.1 responded to Botryosphaeria dothidea and enhanced resistance to B. dothidea. Electrophoretic mobility shift assays, yeast one-hybrid assays, and chromatin immunoprecipitation and quantitative PCR demonstrated that MdWRKY46 can directly bind to a W-box motif in the promoter of MdPBS3.1. Glucuronidase transactivation and luciferase analysis further showed that MdWRKY46 can activate the expression of MdPBS3.1. Finally, B. dothidea inoculation in transgenic apple calli and fruits revealed that MdWRKY46 improved resistance to B. dothidea by the transcriptional activation of MdPBS3.1. Viral vector-based transformation assays indicated that MdWRKY46 elevates SA content and transcription of SA-related genes, including MdPR1, MdPR5, and MdNPR1 in an MdPBS3.1-dependent way. These findings provide new insights into how MdWRKY46 regulates plant resistance to B. dothidea through the SA signaling pathway.


Assuntos
Ascomicetos , Resistência à Doença , Regulação da Expressão Gênica de Plantas , Malus , Proteínas de Plantas , Transdução de Sinais , Ascomicetos/fisiologia , Resistência à Doença/genética , Malus/genética , Malus/microbiologia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Ácido Salicílico/metabolismo , Transdução de Sinais/genética
6.
Plant Mol Biol ; 101(1-2): 149-162, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31267255

RESUMO

KEY MESSAGE: Here we describe that the regulation of MdWRKY31 on MdHIR4 in transcription and translation levels associated with disease in apple. The phytohormone salicylic acid (SA) is a main factor in apple (Malus domestica) production due to its function in disease resistance. WRKY transcription factors play a vital role in response to stress. An RNA-seq analysis was conducted with 'Royal Gala' seedlings treated with SA to identify the WRKY regulatory mechanism of disease resistance in apple. The analysis indicated that MdWRKY31 was induced. A quantitative real-time polymerase chain reaction (qPCR) analysis demonstrated that the expression of MdWRKY31 was induced by SA and flg22. Ectopic expression of MdWRKY31 in Arabidopsis and Nicotiana benthamiana increased the resistance to flg22 and Pseudomonas syringae tomato (Pst DC3000). A yeast two-hybrid screen was conducted to further analyze the function of MdWRKY31. As a result, hypersensitive-induced reaction (HIR) protein MdHIR4 interacted with MdWRKY31. Biomolecular fluorescence complementation, yeast two-hybrid, and pull-down assays demonstrated the interaction. In our previous study, MdHIR4 conferred decreased resistance to Botryosphaeria dothidea (B. dothidea). A viral vector-based transformation assay indicated that MdWRKY31 evaluated the transcription of SA-related genes, including MdPR1, MdPR5, and MdNPR1 in an MdHIR4-dependent way. A GUS analysis demonstrated that the w-box, particularly w-box2, of the MdHIR4 promoter played a major role in the responses to SA and B. dothidea. Electrophoretic mobility shift assays, yeast one-hybrid assay, and chromatin immunoprecipitation-qPCR demonstrated that MdWRKY31 directly bound to the w-box2 motif in the MdHIR4 promoter. GUS staining activity and a protein intensity analysis further showed that MdWRKY31 repressed MdHIR4 expression. Taken together, our findings reveal that MdWRKY31 regulated plant resistance to B. dothidea through the SA signaling pathway by interacting with MdHIR4.


Assuntos
Resistência à Doença , Malus/genética , Doenças das Plantas/imunologia , Reguladores de Crescimento de Planta/farmacologia , Proteínas de Plantas/metabolismo , Ácido Salicílico/farmacologia , Arabidopsis/genética , Arabidopsis/imunologia , Arabidopsis/microbiologia , Ascomicetos/fisiologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Frutas/genética , Frutas/imunologia , Frutas/microbiologia , Regulação da Expressão Gênica de Plantas , Genes Reporter , Malus/imunologia , Malus/microbiologia , Doenças das Plantas/microbiologia , Proteínas de Plantas/genética , Regiões Promotoras Genéticas/genética , Pseudomonas syringae/fisiologia , Plântula/genética , Plântula/imunologia , Plântula/microbiologia , Transdução de Sinais , Tabaco/genética , Tabaco/imunologia , Tabaco/microbiologia , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Técnicas do Sistema de Duplo-Híbrido
7.
New Phytol ; 224(1): 380-395, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31225908

RESUMO

Wounding stress leads to anthocyanin accumulation. However, the underlying molecular mechanism remains elusive. In this study, MdWRKY40 was found to promote wounding-induced anthocyanin biosynthesis in association with MdMYB1 and undergo MdBT2-mediated degradation in apple. We found that MdMYB1, a positive regulator of anthocyanin biosynthesis, was essential for the wounding-induced anthocyanin biosynthesis in apple. MdWRKY40 was identified as an MdMYB1-interacting protein, and enhanced the binding of MdMYB1 to its target genes in response to wounding. We found that MdBT2 interacted physically with MdWRKY40 and was involved in its degradation through the 26S proteasome pathway. Our results demonstrate that MdWRKY40 is a key modulator in the wounding-induced anthocyanin biosynthesis, which provides new insights into the regulation of wounding-induced anthocyanin biosynthesis at both the transcriptional and post-translational levels in apple.

8.
Plant Physiol ; 180(4): 1988-2003, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31221734

RESUMO

Carotenoids exert multifaceted roles to plants and are critically important to humans. Phytoene synthase (PSY) is a major rate-limiting enzyme in the carotenoid biosynthetic pathway. PSY in plants is normally found as a small enzyme family with up to three members. However, knowledge of PSY isoforms in relation to their respective enzyme activities and amino acid residues that are important for PSY activity is limited. In this study, we focused on two tomato (Solanum lycopersicum) PSY isoforms, PSY1 and PSY2, and investigated their abilities to catalyze carotenogenesis via heterologous expression in transgenic Arabidopsis (Arabidopsis thaliana) and bacterial systems. We found that the fruit-specific PSY1 was less effective in promoting carotenoid biosynthesis than the green tissue-specific PSY2. Examination of the PSY proteins by site-directed mutagenesis analysis and three-dimensional structure modeling revealed two key amino acid residues responsible for this activity difference and identified a neighboring aromatic-aromatic combination in one of the PSY core structures as being crucial for high PSY activity. Remarkably, this neighboring aromatic-aromatic combination is evolutionarily conserved among land plant PSYs except PSY1 of tomato and potato (Solanum tuberosum). Strong transcription of tomato PSY1 likely evolved as compensation for its weak enzyme activity to allow for the massive carotenoid biosynthesis in ripe fruit. This study provides insights into the functional divergence of PSY isoforms and highlights the potential to rationally design PSY for the effective development of carotenoid-enriched crops.

9.
Plant Cell Physiol ; 60(10): 2129-2140, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31165159

RESUMO

Apple ring rot is a severe disease that affects the yield and quality of apple fruits worldwide. However, the underlying molecular mechanism that involved in this process still remains largely unexplored. Here, we report that apple POZ/BTB CONTAINING-PROTEIN 1 (MdPOB1), a BTB-BACK domain E3 ligase protein, functions to suppress apple pathogen defense against Botryosphaeria dothidea (B. dothidea). Both in vitro and in vivo assays indicated that MdPOB1 interacted directly with and degraded apple U-box E3 ligase MdPUB29, a well-established positive regulator of plant innate immunity, through the ubiquitin/26S proteasome pathway. A series of transgenic analyses in apple fruits demonstrated that MdPOB1 affected apple pathogen defense against B. dothidea at least partially, if not completely, via regulating MdPUB29. Additionally, it was found that the apple pathogen defense against B. dothidea was correlated with the H2O2 contents and the relative expression of salicylic acid (SA) synthesis- and SA signaling-related genes, which might be regulated via degradation of MdPUB29 by MdPOB1. Overall, our findings provide new insights into the mechanism of the MdPOB1 modulation of apple ring rot resistance, which occur by directly regulating potential downstream target protein MdPUB29 for proteasomal degradation in apple.

11.
Plant Biotechnol J ; 2019 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-31250952

RESUMO

MYB transcription factors (TFs) have been demonstrated to play diverse roles in plant growth and development through interaction with basic helix-loop-helix (bHLH) TFs. MdbHLH33, an apple bHLH TF, has been identified as a positive regulator in cold tolerance and anthocyanin accumulation by activating the expressions of MdCBF2 and MdDFR. In the present study, a MYB TF MdMYB308L was found to also positively regulate cold tolerance and anthocyanin accumulation in apple. We found that MdMYB308L interacted with MdbHLH33 and enhanced its binding to the promoters of MdCBF2 and MdDFR. In addition, an apple RING E3 ubiquitin ligase MYB30-INTERACTING E3 LIGASE 1 (MdMIEL1) was identified to be an MdMYB308L-interacting protein and promoted the ubiquitination degradation of MdMYB308L, thus negatively regulated cold tolerance and anthocyanin accumulation in apple. These results suggest that MdMYB308L acts as a positive regulator in cold tolerance and anthocyanin accumulation in apple by interacting with MdbHLH33 and undergoes MdMIEL1-mediated protein degradation. The dynamic change in MYB-bHLH protein complex seems to play a key role in the regulation of plant growth and development.

12.
J Integr Plant Biol ; 2019 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-31090249

RESUMO

Isochorismate synthase (ICS) plays an essential role in the accumulation of salicylic acid (SA) and plant disease resistance. Diseases caused by Botryosphaeria dothidea affect apple yields. Thus, it is important to understand the role of ICS1 in disease resistance to B. dothidea in apple. In this study, SA treatment enhanced the resistance to B. dothidea. MdICS1 was induced by B. dothidea and enhanced the resistance to B. dothidea. MdICS1 promoter analysis indicated that the W-box was vital for the response to B. dothidea treatment. MdWRKY15 was found to interact with the W-box using yeast one-hybrid screening. Subsequently, the interaction was confirmed by EMSA, yeast one-hybrid, ChIP-PCR, and quantitative PCR assays. Moreover, luciferase and GUS analysis further indicated that MdICS1 was transcriptionally activated by MdWRKY15. Finally, we found the function of MdWRKY15 in the resistance to B. dothidea was partially dependent on MdICS1 from the phenotype of transgenic apples and calli. In summary, we revealed that MdWRKY15 activated the transcription of MdICS1 by directly binding to its promoter to increase the accumulation of SA and the expression of disease-related genes, thereby resulting in the enhanced resistance to B. dothidea in the SA biosynthesis pathway.

13.
Plant Sci ; 283: 396-406, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31128710

RESUMO

In plants, hypersensitive-induced reaction (HIR) proteins are involved in stress responses, especially biotic stress. However, the potential molecular mechanisms of HIR-mediated biotic resistance in plants are rarely reported. We found that apple (Malus domestica) MdHIR4 was localized in the cell nucleus and membrane similar to AtHIR1 in Arabidopsis. Moreover, salicylic acid and the bacterial flagellin flg22 (a conserved, 22-amino acid motif), which are relevant to biotic stress, could induce MdHIR4 expression. Additionally, the transcription level of MdHIR4 was increased by Methyl jasmonate treatment. Ectopic expression of MdHIR4 in Arabidopsis and Nicotiana benthamiana reduced sensitivity to Methyl jasmonate and enhanced resistance to the bacterial pathogen Pst DC3000 (Pseudomonas syringae tomato DC3000). The interaction between MdHIR4 and AtJAZs proteins (AtJAZ3, AtJAZ4, and AtJAZ9) implied that MdHIR4 participated in the jasmonic acid (JA) signaling pathway. We found the expression of JA-related genes and PRs to change in transgenic plants, further demonstrating that MdHIR4 mediated biotic stress through the JA signaling pathway. Repressing the expression of MdHIR4 in apple leaves and calli increased resistance to Botryosphaeria dothidea by influencing the transcription of resistance-related genes. Our findings reveal the resistant function to biotic stress of MdHIR4 in transgenic plants, including Arabidopsis, tobacco, and apple, and identify the regulating mechanism of MdHIR4-related biotic resistance.


Assuntos
Malus/metabolismo , Proteínas de Plantas/metabolismo , Arabidopsis , Ascomicetos , Western Blotting , Membrana Celular/metabolismo , Núcleo Celular/metabolismo , Resistência à Doença , Regulação da Expressão Gênica de Plantas , Malus/fisiologia , Doenças das Plantas/microbiologia , Proteínas de Plantas/fisiologia , Plantas Geneticamente Modificadas , Pseudomonas syringae , Estresse Fisiológico , Transcriptoma , Técnicas do Sistema de Duplo-Híbrido
14.
Planta ; 249(5): 1627-1643, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30826884

RESUMO

MAIN CONCLUSION: This study showed that AP2/EREBP transcription factor MdSHINE2 functioned in mediating cuticular permeability, sensitivity to abscisic acid (ABA), and drought resistance by regulating wax biosynthesis. Plant cuticular wax plays crucial roles in protecting plants from environmental stresses, particularly drought stress. Many enzymes and transcription factors involved in wax biosynthesis have been identified in plant species. In this study, we identified an AP2/EREBP transcription factor, MdSHINE2 from apple, which is a homolog of AtSHINE2 in Arabidopsis. MdSHINE2 was constitutively expressed at different levels in various apple tissues, and the transcription level of MdSHINE2 was induced substantially by abiotic stress and hormone treatments. MdSHINE2-overexpressing Arabidopsis exhibited great change in cuticular wax crystal numbers and morphology and wax composition of leaves and stems. Moreover, MdSHINE2 heavily influenced cuticular permeability, sensitivity to abscisic acid, and drought resistance.


Assuntos
Ácido Abscísico/farmacologia , Secas , Malus/metabolismo , Fator de Transcrição AP-2/metabolismo , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Arabidopsis/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/genética , Malus/efeitos dos fármacos , Fator de Transcrição AP-2/genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
15.
Planta ; 249(4): 1177-1188, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30603792

RESUMO

MAIN CONCLUSION: MdPUB29 is a positive regulator of the defense response to the fungal pathogen Botryosphaeria dothidea possibly by directly regulating the salicylic acid (SA) content as well as SA synthesis-related and signaling-related gene transcription. In plants, ubiquitin E3 ligases containing a U-box domain (PUBs, Plant U-box E3 ubiquitin ligase) have been identified as key regulators of fundamental cellular processes, such as cellular growth, development, and apoptosis, as well as biotic and abiotic stress responses. However, the function of PUBs in apple ring rot remains elusive. Here, we isolated the U-box E3 ligase MdPUB29 from the apple cultivar 'Royal Gala' and characterized its function in plant pathogen defense against Botryosphaeria dothidea. qRT-PCR showed that the expression of MdPUB29 was significantly induced in apple fruits after B. dothidea infection. Overexpression of the MdPUB29 gene in apple calli increased the resistance to B. dothidea infection. In contrast, silencing MdPUB29 in apple calli resulted in reduced resistance. Ectopic expression of MdPUB29 in Arabidopsis also exhibited enhanced resistance to B. dothidea infection compared to that of the wild-type (Col) control. In addition, it was found that the increase of plant pathogen defense was correlated with the increased salicylic acid (SA) content, as well as SA synthesis-related and signaling-related gene transcription in comparison to the wild type. We elucidated the mechanism by which MdPUB29 elevates plant pathogen defense against B. dothidea possibly by regulating the SA pathway.


Assuntos
Ascomicetos , Malus/genética , Doenças das Plantas/microbiologia , Imunidade Vegetal/genética , Proteínas de Plantas/genética , Ubiquitina-Proteína Ligases/genética , Clorofila/metabolismo , Clonagem Molecular , Regulação da Expressão Gênica de Plantas , Glucanos/metabolismo , Malus/enzimologia , Malus/imunologia , Malus/microbiologia , Doenças das Plantas/imunologia , Reguladores de Crescimento de Planta/metabolismo , Proteínas de Plantas/fisiologia , Espécies Reativas de Oxigênio/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Ácido Salicílico/metabolismo , Ubiquitina-Proteína Ligases/fisiologia
16.
New Phytol ; 222(2): 735-751, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30536977

RESUMO

The molecular mechanism of leaf senescence in apple (Malus domestica) is still not fully understood. We used gene expression analysis and protein-protein interactions to decipher the relationships of abscisic acid (ABA) and two proteins, MdbHLH93 and MdBT2, in the senescence process. We found that MdbHLH93 promoted leaf senescence and the expression of senescence-related genes, which exhibited similar effects to ABA on leaf senescence. MdbHLH93 activated directly the transcription of MdSAG18. We also found that an ABA-responsive protein, MdBT2, interacted directly with MdbHLH93, and induced the ubiquitination and degradation of the MdbHLH93 protein, and thus delayed leaf senescence. Our findings provide new insights into the regulatory network of leaf senescence through the functional interactions among ABA, MdbHLH93 and MdBT2.

18.
J Plant Physiol ; 232: 216-225, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30537609

RESUMO

In plants, SIZ1 regulates abiotic and biotic stress responses by promoting the SUMOylation of proteins. The apple MdSIZ1 protein has conserved domains similar to those of Arabidopsis AtSIZ1. Real-time fluorescent quantitative analysis showed that MdSIZ1 gene expression was induced by phosphate-deficient conditions. In addition, the level of SUMOylation was also significantly increased under these conditions. The MYB transcription factor MdPHR1 might be a target for the SUMO protein, which is a phosphorus starvation-dependent protein. Subsequently, an MdSIZ1 expression vector was constructed and transformed in Arabidopsis mutant siz1-2 and apple callus. The MdSIZ1 transgenic Arabidopsis partially complemented the defect phenotype of siz1-2 under phosphate-deficient conditions. The survival rate, length of primary root, and number or density of lateral roots were similar between the transgenic lines and wild type (WT). Under phosphate-deficient conditions, the SUMO conjugate and fresh weight of the MdSIZ1 transgenic apple callus were improved compared with WT. The MdSIZ1 transgenic apple callus grew under phosphate-deficient conditions, whereas the MdSIZ1 sense apple callus did not. Therefore, MdSIZ1 is involved in the regulation of the phosphate-deficiency response in apple.


Assuntos
Ligases/fisiologia , Malus/fisiologia , Fosfatos/deficiência , Proteínas de Plantas/fisiologia , Arabidopsis , Regulação da Expressão Gênica de Plantas , Ligases/metabolismo , Malus/enzimologia , Malus/metabolismo , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Sumoilação
19.
Plant Physiol ; 2018 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-30333149

RESUMO

SIZ1-mediated SUMO modification of target proteins is important for various biological processes related to abiotic stress resistance in plants; however, little is known about its role in resistance toward iron (Fe) deficiency. Here, the SUMO E3 ligase MdSIZ1 was shown to be involved in the plasma membrane (PM) H+-ATPase-mediated response to Fe deficiency. Subsequently, a basic helix-loop-helix (bHLH) transcription factor (TF), MdbHLH104, which acts as a key component in regulating PM H+-ATPase-mediated rhizosphere acidification and Fe uptake in apples (Malus domestica), was identified as a direct target of MdSIZ1. MdSIZ1 directly sumoylated MdbHLH104 both in vitro and in vivo, especially under conditions of Fe deficiency, and this sumoylation was required for MdbHLH104 protein stability. Double substitution of K139R and K153R in MdbHLH104 blocked MdSIZ1-mediated sumoylation in vitro and in vivo, indicating that the K139 and K153 residues were the principal sites of SUMO conjugation. Moreover, the transcript level of the MdSIZ1 gene was substantially induced following Fe deficiency. MdSIZ1 overexpression exerted a positive influence on PM H+-ATPase-mediated rhizosphere acidification and Fe uptake. Our findings reveal an important role for sumoylation in the regulation of PM H+-ATPase-mediated rhizosphere acidification and Fe uptake during Fe deficiency in plants.

20.
Plant Sci ; 276: 181-188, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30348317

RESUMO

Phytohormone ethylene is involved in salt stress response. As a key regulator of ethylene signaling, ethylene response factors (ERFs) have been reported to regulate salt stress tolerance. However, there are few studies on the relationship between ERFs in salt stress response. In this study, we isolated a salt-responsive gene MdERF4. Overexpression of MdERF4 negatively regulated salt stress tolerance and ethylene response, which was contrary to that of MdERF3 transgenic lines. Biochemical assays showed that MdERF4 directly bound to the DRE motif of MdERF3 promoter and suppressed its transcription. In addition, genetic analysis revealed that MdERF4 was involved in ethylene-mediated salt tolerance. Taken together, these findings demonstrated the transcriptional regulation between MdERF4 and MdERF3 in salt stress response and provided new insight into the ethylene-modulated salt stress response.


Assuntos
Etilenos/metabolismo , Regulação da Expressão Gênica de Plantas , Malus/genética , Reguladores de Crescimento de Planta/metabolismo , Proteínas de Plantas/metabolismo , Transdução de Sinais , Malus/fisiologia , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas , Salinidade , Tolerância ao Sal , Cloreto de Sódio/metabolismo , Estresse Fisiológico , Fatores de Transcrição/metabolismo
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