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In Asian cultivated rice ( Oryza sativa), distinct mechanisms to survive flooding are activated in two groups of varieties. Submergence-tolerant rice varieties possessing the SUBMERGENCE1A ( SUB1A) gene display reduced growth during flash floods at the seedling stage and resume growth after the flood recedes, whereas deepwater rice varieties possessing the SNORKEL1 ( SK1) and SNORKEL2 ( SK2) genes display enhanced growth based on internodal elongation during prolonged submergence at the mature stage. In this study, we investigated the occurrence of these growth responses to submergence in the wild rice species Oryza grandiglumis, which is native to the Amazon floodplains. When subjected to gradual submergence, adult plants of O. grandiglumis accessions showed enhanced internodal elongation with rising water level and their growth response closely resembled that of deepwater varieties of O. sativa with high floating capacity. On the other hand, when subjected to complete submergence, seedlings of O. grandiglumis accessions displayed reduced shoot growth and resumed normal growth after desubmergence, similar to the response of submergence-tolerant varieties of O. sativa. Neither SUB1A nor the SK genes were detected in the O. grandiglumis accessions. These results indicate that the O. grandiglumis accessions are capable of adapting successfully to flooding by activating two contrasting mechanisms as the situation demands and that each mechanism of adaptation to flooding is not mediated by SUB1A or the SK genes. [ABSTRACT FROM AUTHOR]

ETHYLENE RESPONSE FACTORs (ERF) transcription factors (TFs) constitute a large transcriptional regulator family belonging to the AP2/ERF superfamily and are implicated in a range of biological processes. However, the specific roles of individual ERF family members in biotic or abiotic stress responses and the underlying molecular mechanism still need to be elucidated. In the present study, a cDNA encoding a member of ethylene response factor (ERF) transcription factor,CaERF5,was isolated from pepper.Sequence analysis showed that CaERF5 contains a typical 59 amino acid AP2/ERF DNA-binding domain, two highly conserved amino acid residues (14th alanine (A) and 19th aspartic acid (D)), a putative nuclear localisation signal (NLS), a CMIX-2 motif in the N-terminal region and two putative MAP kinase phosphorylation site CMIX-5 and CMIX-6 motifs. It belongs to group IXb of the ERF subfamily. A CaERF5-green fluorescence protein (GFP) fusion transiently expressed in onion epidermal cells localized to thenucleus.CaERF5 transcripts were induced by Ralstonia solanacearum infection, salicylic acid (SA), methyl jasmonate (MeJA) and ethephon (ETH) treatments. Constitutive expression of the CaERF5 gene in tobacco plants upregulated transcript levels of a set of defence-related genes and enhanced resistance to R. solanacearum infection. Our results suggest that CaERF5 acts as a positive regulator in plant resistance to R. solanacearum infection and show that overexpression of this transcription factor can be used as a tool to enhance disease resistance in crop species. [ABSTRACT FROM AUTHOR]

The plant hormones ethylene, jasmonic acid and salicylic acid have interconnecting roles during the response of plant tissues to mutualistic and pathogenic symbionts., We used morphological studies of transgenic- or hormone-treated Populus roots as well as whole-genome oligoarrays to examine how these hormones affect root colonization by the mutualistic ectomycorrhizal fungus Laccaria bicolor S238N., We found that genes regulated by ethylene, jasmonic acid and salicylic acid were regulated in the late stages of the interaction between L. bicolor and poplar. Both ethylene and jasmonic acid treatments were found to impede fungal colonization of roots, and this effect was correlated to an increase in the expression of certain transcription factors (e.g. ETHYLENE RESPONSE FACTOR1) and a decrease in the expression of genes associated with microbial perception and cell wall modification. Further, we found that ethylene and jasmonic acid showed extensive transcriptional cross-talk, cross-talk that was opposed by salicylic acid signaling., We conclude that ethylene and jasmonic acid pathways are induced late in the colonization of root tissues in order to limit fungal growth within roots. This induction is probably an adaptive response by the plant such that its growth and vigor are not compromised by the fungus. [ABSTRACT FROM AUTHOR]

Hypoxia, or oxygen deficiency, is an abiotic stress that plants are subjected to during soil flooding. Therefore, plants have evolved adaptive mechanisms to sense oxygen deficiency and make coordinated changes at the transcriptional level. The results of this study show that the interplay between hydrogen peroxide and ethylene affected the transcriptional responses of ERF73/HRE1 and ADH1 during hypoxia signaling. HO affected the abundance of ERF73/HRE1 and ADH1 mRNAs in both wild-type Arabidopsis and the ethylene-insensitive mutant, ein2-5. Promoter analysis was conducted using transgenic plants expressing an ERF73/HRE1 promoter-β- glucuronidase reporter gene construct. GUS staining observations and activity assays showed that GUS was regulated similarly to, and showed a similar accumulation pattern as, HO during hypoxia. The transcript levels of ERF73/HRE1 and ADH1 were significantly decreased in the WT by combined hypoxia and diphenylene iodonium chloride (DPI, an NADPH oxidase inhibitor) treatment. In ein2-5, induction of ERF73/HRE1 was also reduced significantly by the combined hypoxia and DPI treatment. In contrast, ADH1 mRNA levels only slightly decreased after this treatment. When DPI was supplied at different time points during hypoxia treatment, HO had critical effects on regulating the transcript levels of ERF73/HRE1 and ADH1 during the early stages of hypoxia signaling. The induction of hypoxia-inducible genes encoding peroxidases and cytochrome P450s was affected, and accumulation of HO was reduced, in ein2-5 during hypoxic stress. Together, these results demonstrate that HO plays an important role during primary hypoxia signaling to control the transcriptional responses of ERF73/ HRE1 and ADH1 via modulation of ethylene signaling. [ABSTRACT FROM AUTHOR]

• Ethylene and carotenoid metabolism played important roles during rachis senescence. • VvEIL2 negatively regulated expression of key genes in carotenoid metabolism. • VvEIL4 positively regulated gene expression in ethylene synthesis pathway. To understand the mechanisms underlying rachis browning and how to delay post-harvest rachis senescence, 'Shine Muscat' grape clusters were treated by 1-methylcyclopropene before cold storage. Rachis browning index, ethylene production, and carotenoid content were determined, and the transcriptome of rachis and the regulation of VvEIL2 and VvEIL4 were explored. The results indicated that 1-MCP treatment inhibited rachis browning, and ethylene production and carotenoid content were decreased in the rachis compared to the control in the 2nd week of storage. Transcriptome analysis showed that carotenoid synthesis and lysine degradation pathways were the most enriched during rachis senescence. Transient over-expression of VvEIL4 in 'Thompson Seedless' grape leaves induced VvACS5 , VvACO2 , and VvERF95 expression and ethylene production. Both VvEIL4 and VvERF95 could activate VvACS5 and VvACO2 promoters. Transient over-expression of VvEIL2 in grape leaves decreased the transcript levels of key genes in carotenoid metabolism. Dual-luciferase assays further verified the activation of the VvCrtISO promoter by VvEIL2 was inhibited. These results suggested that VvEIL2 and VvEIL4 regulate ethylene synthesis and carotenoid metabolism during the senescence of grape rachis. [ABSTRACT FROM AUTHOR]

Ethylene Response Factors ( ERFs) are downstream components of the ethylene signal transduction pathway, although their role in ethylene-dependent developmental processes remains poorly understood. As the ethylene-inducible tomato Sl- ERF. B3 has been shown previously to display a strong binding affinity to GCC-box-containing promoters, its physiological significance was addressed here by a reverse genetics approach. However, classical up- and down-regulation strategies failed to give clear clues to its roles in planta, probably due to functional redundancy among ERF family members. Expression of a dominant repressor ERF. B3- SRDX version of Sl- ERF. B3 in the tomato resulted in pleiotropic ethylene responses and vegetative and reproductive growth phenotypes. The dominant repressor etiolated seedlings displayed partial constitutive ethylene response in the absence of ethylene and adult plants exhibited typical ethylene-related alterations such as leaf epinasty, premature flower senescence and accelerated fruit abscission. The multiple symptoms related to enhanced ethylene sensitivity correlated with the altered expression of ethylene biosynthesis and signaling genes and suggested the involvement of Sl- ERF. B3 in a feedback mechanism that regulates components of ethylene production and response. Moreover, Sl- ERF. B3 was shown to modulate the transcription of a set of ERFs and revealed the existence of a complex network interconnecting different ERF genes. Overall, the study indicated that Sl- ERF. B3 had a critical role in the regulation of multiple genes and identified a number of ERFs among its primary targets, consistent with the pleiotropic phenotypes displayed by the dominant repression lines. [ABSTRACT FROM AUTHOR]

Abstract: Ethylene response factor (ERF) functions as an important plant-specific transcription factor in regulating biotic and abiotic stress response through interaction with various stress pathways. We previously obtained three ERF members, VpERF1, VpERF2, and VpERF3 from a highly powdery mildew (PM)-resistant Chinese wild Vitis pseudoreticulata cDNA full-length library. To explore their functions associated with plant disease resistance or biotic stress, we report here to characterize three ERF members from this library. PM-inoculation analysis on three different resistant grapevine genotypes revealed that three VpERFs displayed significant responses, but a different expression pattern. Over-expression of VpERF1, VpERF2, and VpERF3 in transgenic tobacco plants demonstrated that VpERF2 and VpERF3 enhanced resistance to both bacterial pathogen Ralstonia solanacearum and fungal pathogen Phytophtora parasitica var. nicotianae Tucker. Importantly, VpERF1-overexpressing transgenic Arabidopsis plants increased susceptibility toward these pathogens. Investigation on drought, cold, and heat treatments suggested, VpERF2 was distinctly induced, whereas VpERF3 displayed a very weak response and VpERF1 was distinctly induced by drought and heat. Concurrently, VpERF3 was significantly induced by salicylic acid (SA), methyl jasmonate (MeJA), and ET. Our results showed that the three VpERFs from Chinese wild V. pseudoreticulata play different roles in either preventing disease progression via regulating the expression of relevant defense genes, or directly involving abiotic stress responsive pathways. [Copyright &y& Elsevier]

Alternative medicinal agents, such as the herb Bupleurum, are increasingly used in modern medicine to supplement synthetic drugs. First, we present a review of the currently known effects of triterpene saponins-saikosaponins of Bupleurum species. The putative biosynthetic pathway of saikosaponins in Bupleurum species is summarized, followed by discussions on identification and characterization of genes involved in the biosynthesis of saikosaponins. The purpose is to provide a brief review of gene extraction, functional characterization of isolated genes and assessment of expression patterns of genes encoding enzymes in the process of saikosaponin production in Bupleurum species, mainly B. kaoi. We focus on the effects of MeJA on saikosaponin production, transcription patterns of genes involved in biosynthesis and on functional depiction. [ABSTRACT FROM AUTHOR]

A new ethylene response factor (ERF), GmERF6, was isolated from soybean. Protein sequence alignment of GmERF6 revealed an AP2/ERF domain, two putative nuclear localization signals (NLSs) and an ERF-associated amphiphilic repression (EAR) motif. Real-time quantitative PCR analysis revealed that the expression of GmERF6 was differentially induced in soybean seedlings by drought, salt, cold, salicylic acid, ethylene, abscisic acid and methyl jasmonate. Transient expression experiments demonstrated that GmERF6 functions as a transcriptional repressor to downregulate the transcriptional levels of the reporter gene and repress the activated ability of other transcriptional activator. Transgenic Arabidopsis lines constitutively expressing GmERF6 showed an increased tolerance to drought compared to wild-type plants. [ABSTRACT FROM AUTHOR]

The N-end rule pathway regulates protein degradation, which depends on exposed N-terminal sequences in prokaryotes and eukaryotes. In plants, conserved and specific enzymes stimulate selective proteolysis. Although a number of developmental and growth phenotypes have been reported for mutants in the N-end rule, its function has remained unrelated to specific physiological pathways. The first report of the direct involvement of the N-end rule in stress responses focused on hypoxic signaling and how the oxygen-dependent oxidation of cystein promotes the N-end rule-mediated degradation of ethylene responsive factor (ERF)-VII proteins, the master regulators of anaerobic responses. It has been suggested that plants have evolved specific mechanisms to tune ERF-VII availability in the nucleus. In this review, we speculate that ERF-VII proteins are reversibly protected from degradation via membrane sequestration. The oxidative response in plants subjected to anoxic conditions suggests that reactive oxygen and nitrogen species (reactive oxygen species and reactive nitrogen species) may interact or interfere with the N-end rule pathway-mediated response to hypoxia. [ABSTRACT FROM AUTHOR]

Plants under pathogen attack produce high levels of the gaseous phytohormone ethylene to induce plant defense responses via the ethylene signaling pathway. The 1-aminocyclopropane-1-carboxylate synthase (ACS) is a critical rate-limiting enzyme of ethylene biosynthesis. Transcriptional and post-translational upregulation of ACS2 and ACS6 by the mitogen-activated protein kinases MPK3 and MPK6 are previously shown to be crucial for pathogen-induced ethylene biosynthesis in Arabidopsis. Here, we report that the fungal pathogen Botrytis cinerea-induced ethylene biosynthesis in Arabidopsis is under the negative feedback regulation by ethylene signaling pathway. The ethylene response factor ERF1A is further found to act downstream of ethylene signaling to negatively regulate the B. cinerea-induced ethylene biosynthesis via indirectly suppressing the expression of ACS2 and ACS6. Interestingly, ERF1A is shown to also upregulate defensin genes directly and therefore promote Arabidopsis resistance to B. cinerea. Furthermore, ERF1A is identified to be a substrate of MPK3 and MPK6, which phosphoactivate ERF1A to enhance its functions in suppressing ethylene biosynthesis and inducing defensin gene expression. Taken together, our data reveal that ERF1A and its phosphorylation by MPK3/MPK6 not only mediate the negative-feedback regulation of the B. cinerea-induced ethylene biosynthesis, but also upregulate defensin gene expression to increase Arabidopsis resistance to B. cinerea., Competing Interests: Conflict of interest The authors declare no competing interests., (Copyright © 2022 Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, and Genetics Society of China. Published by Elsevier Ltd. All rights reserved.)

The full-length cDNA sequence of AaERF3 was cloned and characterized from Artemisia annua. The bioinformatic analysis and phylogenetic tree analysis implied that the AaERF3 encoded a putative protein of 193 amino acids which formed a closely related subgroup with AtERF1, ERF1 and ORA59 in Arabidopsis. The result of subcellular localization showed that AaERF3 targeted to both of the nuclei and the cytoplasm. The qRT-PCR analysis showed that Green young alabastrums had the highest expression level of AaERF3 in the 5-months-old plants. The qRT-PCR analysis also revealed that ABA, Wound and Cold treatments significantly enhanced the transcript expression of AaERF3. MeJA and Ethylene treatment could also slightly induce the accumulation of AaERF3 transcription. [ABSTRACT FROM AUTHOR]

Abstract: Two ethylene response factor (ERF) genes, IbERF1 and IbERF2, were isolated from a library of expressed sequence tags (EST) prepared from suspension-cultured cells and dehydration-treated fibrous roots of sweetpotato (Ipomoea batatas). The deduced IbERFs contained a nuclear localization signal and the AP2/ERF DNA-binding domain. RT-PCR analysis revealed that IbERF1 was expressed abundantly during the growth of suspension-cultured cells, whereas the expression levels of IbERF2 transcripts were high in fibrous, thick pigmented roots. Two ERF genes also showed different responses to various types of abiotic stress and pathogen infection. Transient expression of the two ERF genes in tobacco (Nicotiana tabacum) leaves resulted in increased transcript levels of the pathogenesis-related 5 (PR5) gene, the early response to dehydration ten gene (ERD10), the CuZn superoxide dismutase gene (CuZnSOD) and the catalase gene (CAT). It is suggested that the two ERF genes play roles in the stress defense-signaling pathway as transcriptional regulators of the PR5, ERD10, CuZnSOD and CAT genes. [Copyright &y& Elsevier]

Ethylene response factors (ERFs) are involved in many plant development events and stress defenses. In this study, an ERF gene, VvERF3b, was cloned from the leaves of Vitis vinifera. VvERF3b belongs to ERF group VIIIa. Expression of the gene was induced by abscisic acid, ethephon, and salicylic acid, but not by NaCl. Promoter sequence analysis of the VvERF3b gene revealed that there are several potential cis-acting elements that may be potentially recognized and bound by the transcription factors related to hormones and stress responses. Deletion analysis showed that the 5′-flanking sequence of −1047 to −585 from the transcriptional start site is essential to the high expression of the VvERF3b gene, whereas the sequence fragment of −1324 to −1047 revealed suppression effect. The result indicated that the region appears to contain cis-acting elements that can be bound by the proteins in a transcription complex to induce the inhibition of gene expression. [ABSTRACT FROM AUTHOR]

A novel member of the AP2/ERF transcription factor family, SlERF5, was identified from a tomato mature leaf cDNA library screen. The complete DNA sequence of SlERF5 encodes a putative 244-amino acid DNA-binding protein which most likely acts as a transcriptional regulator and is a member of the ethylene responsive factor (ERF) superfamily. Analysis of the deduced SlERF5 protein sequence showed that it contained an ERF domain and belonged to the class III group of ERFs proteins. Expression of SlERF5 was induced by abiotic stress, such as high salinity, drought, flooding, wounding and cold temperatures. Over-expression of SlERF5 in transgenic tomato plants resulted in high tolerance to drought and salt stress and increased levels of relative water content compared with wild-type plants. This study indicates that SlERF5 is mainly involved in the responses to abiotic stress in tomato. [ABSTRACT FROM AUTHOR]

A novel BnERF50 gene was identified from transcription eDNA chip of Zhongshuang 9 (Brassica napus L.) against Sclerotinia sclerotiorum infection. BLAST result showed BnERF50 protein has a typical and conserved ERF (ethylene response factor) domain which belongs to ERF family. The expression of BnERF50 was up - regulated significantly at 24h after S. sclerotiorum inoculation on B. napus. Over - expression of BnERF50 in transgenic Arabidopsis thaliana activated the expressions of pathogenesis - related (PR) genes PDF1.2 and ChiB, and it also significantly enhanced the plant resistance to the necrotrophic fungi S. sclerotiorum. [ABSTRACT FROM AUTHOR]

Abstract: Three novel ethylene response factor (ERF) genes, BkERF1, BkERF2.1 and BkERF2.2, were isolated from a medicinal plant Bupleurum kaoi. The deduced BkERFs contain a canonical nuclear localization signal and an ERF/AP2 DNA binding domain. RNA gel blot analysis revealed that BkERF1 and BkERF2.1 were ubiquitously expressed at low levels in all parts of mature plants, and that BkERF2.2 was expressed at moderate levels in vegetative tissues. Exogenous application of methyl jasmonate induced BkERF1/2.1/2.2 transcripts. BkERF2.2 transcript levels were slightly increased by addition of ethephon and salicylic acid. BkERFs were localized in the plant nucleus and functioned as transcriptional activators. In B. kaoi cells overexpressing BKERFs, inoculation with Botrytis cinerea increased expression of some defense genes which are associated with enhanced disease resistance. Similarly, overexpression of BkERFs in transgenic Arabidopsis thaliana resulted in elevated mRNA levels of the defense gene PDF1.2, and in enhanced resistance to B. cinerea. Collectively, these results provide evidence that BkERFs mediate the expression of defense-related genes in plants. [ABSTRACT FROM AUTHOR]

Ethylene responsive transcription factors have been shown to be intimately connected to plant development, defense responses and stress signaling pathways and in order to use them for plant improvement, we need to have better understanding of these proteins. In this study, 85 ERF genes have been identified from tomato using raw EST data in various public repositories. Phylogenetic analysis with tomato ERF domains revealed their distribution in all the groups, previously identified in model systems. MEME motif analysis resulted in identification of conserved domains, characteristic to member of each clade, in addition to ERF domain. Expression analysis during vegetative and reproductive stages of development using QPCR and tomato GeneChip arrays, revealed their tissue-specific/preferential accumulation. In total, 57 genes were found to be differentially expressed during temporal stages of tomato fruit development. The expression analysis of 23 ERF family genes representing each clade in response to seven abiotic stress treatments revealed their differential expression in response to more than one abiotic stress treatments. Results suggest that ERF genes play diverse roles in plant's life and comprehensive data generated will be helpful in conducting functional genomics studies to understand their precise role during plant development and stress response. [ABSTRACT FROM AUTHOR]

A new member of the AP2/ERF transcription factor family, GmERF3, was isolated from soybean. Sequence analysis showed that GmERF3 contained an AP2/ERF domain of 58 amino acids and two putative nuclear localization signal (NLS) domains. It belonged to a group IV protein in the ERF (ethylene response factor) subfamily as typified by a conserved N-terminal motif [MCGGAI(I/L)]. Expression of GmERF3 was induced by treatments with high salinity, drought, abscisic acid (ABA), salicylic acid (SA), jasmonic acid (JA), ethylene (ET), and soybean mosaic virus (SMV), whereas there was no significant GmERF3 mRNA accumulation under cold stress treatment. GmERF3 could bind to the GCC box and DRE/CRT element, and was targeted to the nucleus when transiently expressed in onion epidermal cells. The GmERF3 protein fused to the GAL4 DNA-binding domain to activate transcription of reporter genes in yeast. Ectopic expression of the GmERF3 gene in transgenic tobacco plants induced the expression of some PR genes and enhanced resistance against infection by Ralstonia solanacearum, Alternaria alternata, and tobacco mosaic virus (TMV), and gave tolerance to high salinity and dehydration stresses. Furthermore, overexpression of GmERF3 in transgenic tobacco led to higher levels of free proline and soluble carbohydrates compared to wild-type plants under drought conditions. The overall results suggested that GmERF3 as an AP2/ERF transcription factor may play dual roles in response to biotic and abiotic stresses in plants. [ABSTRACT FROM PUBLISHER]

Thinopyrum intermedium is resistant to many different pathogens. To understand the roles of ethylene response factors (ERFs) in defence responses, the first member of the ERF family in T. intermedium, TiERF1, was characterized and functionally analysed in this study. The TiERF1 gene encodes a putative protein of 292 amino acids, belonging to the B3 subgroup of the ERF transcription factor family. Biochemical assays demonstrated that the TiERF1 protein is capable of binding to the GCC box, a cis-element present in the promoters of pathogenesis-related (PR) genes, and possessing transactivation activity, as well as localizing to the nucleus. The transcript of TiERF1 in T. intermedium is rapidly induced by infection with Rhizoctonia cerealis, Fusarium graminearum, or Blumeria graminis, and ethylene, jasmonic acid, and salicylic acid treatments. More importantly, the ectopic expression of TiERF1 in tobacco activated the transcript of the PR genes of tobacco with a GCC box cis-element, and ACO and ACS genes key to ethylene synthesis, and in turn improved the resistance level to Alternaria alternata and tobacco mosaic virus, as well as causing some phenotypic changes associated with ethylene response in the transgenic tobacco plants. Taken together, TiERF1 protein as an ERF transcription activator positively regulates defence responses via the activation of some defence-related genes. [ABSTRACT FROM PUBLISHER]

In contrast to other cereals, typical barley cultivars have caryopses with adhering hulls at maturity, known as covered (hulled) barley. However, a few barley cultivars are a free-threshing variant called naked (hulless) barley. The covered/naked caryopsis is controlled by a single locus (nud) on chromosome arm 7HL. On the basis of positional cloning, we concluded that an ethylene response factor (ERF) family transcription factor gene controls the covered/naked caryopsis phenotype. This conclusion was validated by (I) fixation of the 17-kb deletion harboring the ERF gene among all 100 naked cultivars studied; (ii) two x-ray-induced nud alleles with a DNA lesion at a different site, each affecting the putative functional motif; and (iii) gene expression strictly localized to the testa. Available results indicate the monophyletic origin of naked barley. The Nud gene has homology to the Arabidopsis WIN1/SHN1 transcription factor gene, whose deduced function is control of a lipid biosynthesis pathway. Staining with a lipophilic dye (Sudan black B) detected a lipid layer on the pericarp epidermis only in covered barley. We infer that, in covered barley, the contact of the caryopsis surface, overlaid with lipids to the inner side of the hull, generates organ adhesion. [ABSTRACT FROM AUTHOR]

Two new genes,LeERF1andLeERF2, were isolated from a tomato (Lycopersicon esculentumcv. Lichun) cDNA library. Phylogenetic analysis indicated that they encoded Ethylene Responsive Element Binding Proteins (EREBPs), characterized by a conserved ERF (ethylene response factor) domain of specific binding plant cis-acting elements GCC box. Both LeERF1 and LeERF2 proteins were obtained via prokaryotic expression and purification. Electrophoretic mobility shift assay showed that LeERF1 and LeERF2 protein could bind to the promoter of theNP24gene coding for pathogenesis-related protein osmotin precursor but not the mutant promoter where its GCC box was deleted. Polyclonal antibodies of LeERF1 and LeERF2 blocked their bindingin vitro. [ABSTRACT FROM AUTHOR]

Four new members of the ERF (ethylene-response factor) family of plant-specific DNA-binding (GCC box) factors were isolated from tomato fruit (LeERF1–4). Phylogenetic analysis indicated that LeERF2 belongs to a new ERF class, characterized by a conserved N-terminal signature sequence. Expression patterns and cis/trans binding affinities differed between the LeERFs. Combining experimental data and modeled three-dimensional analysis, it was shown that binding affinity of the LeERFs was affected by both the variation of nucleotides surrounding the DNA cis-element sequence and the nature of critical amino acid residues within the ERF domain. [Copyright &y& Elsevier]

Background: Walnut is an important economic tree species with prominent economic value and ecological functions. However, in recent years, walnuts have become susceptible to drought stress, resulting in a decline in comprehensive benefits. Therefore, it is necessary to identify the regulatory molecular mechanism associated with walnut response to drought. In many plants, ethylene responsive factor ( ERF ) gene family plays important roles in response to biotic and abiotic stress, especial drought. Therefore, the identification and characterisation of walnut ERF genes will benefit walnut with regard to the clarification of drought response mechanism as well as the management, production, and quality of plantations., Methods: 'ERF' was compared against the walnut transcriptome, and the JrERF s with a complete open reading frame (ORF) were identified by ORF Finder. The molecular weights, amino acid residues, and theoretical isoelectric point (pI) were predicted by ExPASy. The distribution of JrERF s in chromosome locations was determined based on walnut genome data from NCBI. The intron-exon structures and conserved domains were analysed using Gene Structure Display Server 2.0 and CD-Search, accordingly. Multi-sequence alignment and a phylogenetic tree were constructed by ClustalX2.1 and MEGA7, respectively. The conserved motifs were acquired using MEME. Total RNA was isolated using the cetyltrimethylammonium ammonium bromide (CTAB) method (Yang et al., 2018). Gene expression was determined by using real-time quantitative polymerase chain reaction (qRT-PCR) analysis and calculated according to the 2 -ΔΔCT method (Livak & Schmittgen, 2001)., Results: A total of 44 JrERF s were identified from the walnut transcriptome, whose ORFs were 450-1,239 bp in length. The molecular weights of the JrERF proteins (consisting 149-412 amino acids) were 16.81-43.71 kDa, with pI ranging from 4.8 ( JrERF11 ) to 9.89 ( JrERF03 ). The JrERF s can be divided into six groups (B1-B6), and among the groups, B6 contained the most number of members. Each JrERF contained 1-6 motifs and each motif comprised 9-50 amino acids. Among the motifs, motif1, motif2, and motif3 were the most abundant. More than 40% of JrERF s were up-regulated continuously when subjected to ethephon (ETH), PEG 6000 , and PEG 6000 +ETH treatments. Of all the JrERFs, JrERF11 showed the highest expression. Therefore, we conclude that walnut ERF genes are highly conserved and involved in the regulation of drought response in the presence of ETH. JrERFs are possibly important candidate genes for molecular breeding; hence, the findings of this study provides the theoretical basis for further investigation of ERF genes in walnut and other species., Competing Interests: The authors declare that they have no competing interests., (© 2021 Wang et al.)

The effects of CO2 pretreatment before cold storage on tomato quality were investigated using physicochemical and transcriptome changes. Harvested tomatoes were treated with 30% or 60% CO2 for 3 h before storage at 4 °C for 14 d (cold storage), followed by transfer to 20 °C for 8 d (ambient conditions). The CO2-treated fruits were firmer with a better appearance than untreated fruits, even after being transferred from 4 °C storage to 20 °C for 8 d. CO2 pretreatment coupled with cold storage synergistically delayed tomato ripening by reducing respiration and lowering lycopene production. The tomatoes treated with 30% and 60% CO2 had fewer pits than untreated fruits after cold storage, even after being transferred to ambient conditions. Moreover, the 60% CO2 treatment significantly suppressed the decay rate. Transcriptome and metabolome functional enrichment analyses commonly showed the involvement of CO2-responsive genes or metabolites in sucrose and starch metabolism, as well as biosynthesis of secondary metabolites—in particular, glycolysis reduction. The most frequently detected domain was the ethylene-responsive factor. These results indicate that altered ethylene biosynthesis and ethylene signaling, via ethylene-responsive transcription factors and respiration-related pathways, appear to control CO2-induced fruit quality. [ABSTRACT FROM AUTHOR]

Ethylene-responsive elements (EREs), such as the GCC box, are critical for ethylene-regulated transcription in plants. Our previous work identified a 19-bp AC-rich element (ACE) in the promoter of bean (Phaseolus vulgaris) metal response element-binding transcription factor 1 (PvMTF-1). Ethylene response factor 15 (PvERF15) directly binds ACE to enhance PvMTF-1 expression. As a novel ERF-binding element, ACE exhibits a significant difference from the GCC box. Here, we demonstrated that ACE serves as an ERE in Arabidopsis. It conferred the minimal promoter to respond to the ethylene stress and inhibition of ethylene. Moreover, the cis-acting element ACE could specifically bind the nuclear proteins in vitro. We further revealed that the first 9-bp sequence of ACE (ACEcore) is importantly required by the binding of nuclear proteins. In addition, PvERF15 and PvMTF-1 were strongly induced by ethylene in bean seedlings. Since PvERF15 activates PvMTF-1 via ACE, ACE is involved in ethylene-induced PvMTF-1 expression. Taken together, our findings provide genetic and biochemical evidence for a new ERE. [ABSTRACT FROM AUTHOR]

Ustilago maydis is the causal agent of maize smut disease. During the colonization process, the fungus secretes effector proteins that suppress immune responses and redirect the host metabolism in favor of the pathogen. As effectors play a critical role during plant colonization, their identification and functional characterization are essential to understanding biotrophy and disease. Using biochemical, molecular, and transcriptomic techniques, we performed a functional characterization of the U. maydis effector Jasmonate/Ethylene signaling inducer 1 (Jsi1). Jsi1 interacts with several members of the plant corepressor family Topless/Topless related (TPL/TPR). Jsi1 expression in Zea mays and Arabidopsis thaliana leads to transcriptional induction of the ethylene response factor (ERF) branch of the jasmonate/ethylene (JA/ET) signaling pathway. In A. thaliana, activation of the ERF branch leads to biotrophic susceptibility. Jsi1 likely activates the ERF branch via an EAR (ET-responsive element binding-factor-associated amphiphilic repression) motif, which resembles EAR motifs from plant ERF transcription factors, that interacts with TPL/TPR proteins. EAR-motif-containing effector candidates were identified from different fungal species, including Magnaporthe oryzae, Sporisorium scitamineum, and Sporisorium reilianum. Interaction between plant TPL proteins and these effector candidates from biotrophic and hemibiotrophic fungi indicates the convergent evolution of effectors modulating the TPL/TPR corepressor hub., (© 2020 The Authors New Phytologist © 2020 New Phytologist Foundation.)

Background: VviERF6Ls are an uncharacterized gene clade in Vitis with only distant Arabidopsis orthologs. Preliminary data indicated these transcription factors may play a role in berry development and extreme abiotic stress responses. To better understand this highly duplicated, conserved clade, additional members of the clade were identified in four Vitis genotypes. A meta-data analysis was performed on publicly available microarray and RNA-Seq data (confirmed and expanded with RT-qPCR), and Vitis VviERF6L1 overexpression lines were established and characterized with phenotyping and RNA-Seq., Results: A total of 18 PN40024 VviERF6Ls were identified; additional VviERF6Ls were identified in Cabernet Sauvignon, Chardonnay, and Carménère. The amino acid sequences of VviERF6Ls were found to be highly conserved. VviERF6L transcripts were detected in numerous plant organs and were differentially expressed in response to numerous abiotic stresses including water deficit, salinity, and cold as well as biotic stresses such as red blotch virus, N. parvum, and E. necator. VviERF6Ls were differentially expressed across stages of berry development, peaking in the pre-veraison/veraison stage and retaining conserved expression patterns across different vineyards, years, and Vitis cultivars. Co-expression network analysis identified a scarecrow-like transcription factor and a calmodulin-like gene with highly similar expression profiles to the VviERF6L clade. Overexpression of VviERF6L1 in a Seyval Blanc background did not result in detectable morphological phenotypes. Genes differentially expressed in response to VviERF6L1 overexpression were associated with abiotic and biotic stress responses., Conclusions: VviERF6Ls represent a large and distinct clade of ERF transcription factors in grapevine. The high conservation of protein sequence between these 18 transcription factors may indicate these genes originate from a duplication event in Vitis. Despite high sequence similarity and similar expression patterns, VviERF6Ls demonstrate unique levels of expression supported by similar but heterogeneous promoter sequences. VviERF6L gene expression differed between Vitis species, cultivars and organs including roots, leaves and berries. These genes respond to berry development and abiotic and biotic stresses. VviERF6L1 overexpression in Vitis vinifera results in differential expression of genes related to phytohormone and immune system signaling. Further investigation of this interesting gene family is warranted.

The ethylene response factor (ERF) plays a crucial role in plant innate immunity. However, the molecular function of ERF in response to Exserohilum turcicum ( E . turcicum ) remains unknown in maize. In this study, a novel ERF gene, designated as ZmERF105 , was firstly isolated and characterized. The ZmERF105 protein contains an APETALA2/ETHYLENE RESPONSIVE FACTOR (AP2/ERF) domain and a conserved LSPLSPHP motif in its C-terminal region. ZmERF105 protein was exclusively localized to the nucleus. ZmERF105 expression responded to E . turcicum treatment. Yeast one-hybrid and transcription activity assays revealed that ZmERF105 is an activator of transcription and binds to GCC-box elements. Over-expression of ZmERF105 was shown to increase maize resistance against E . turcicum , and erf105 mutant lines displayed opposite phenotype. Moreover, the activities of superoxide dismutase (SOD) and peroxidase (POD) in the ZmERF105 over-expression lines were markedly higher than in the wild-type maize lines (WT) after infection with E . turcicum , and were compromised in the erf105 mutant lines. Simultaneously, ZmERF105 over-expression lines enhanced the expression of several pathogenesis-related (PR) genes, including ZmPR1a , ZmPR2 , ZmPR5 , ZmPR10.1 , and ZmPR10.2 after infection with E . turcicum . In contrast, the expression of PR genes was reduced in erf105 mutant lines. Our work reveals that ZmERF105 as a novel player of the ERF network and positively regulates the maize resistance response to E . turcicum ., (Copyright © 2020 Zang, Lv, Liu, Yang, Ci, Ren, Wang, Wu, Ma, Jiang and Yang.)

Iron (Fe) deficiency limits the yield of fruit trees. When subjected to Fe deficiency, H+ secretion increases in the rhizosphere of dicotyledonous plants and pH decreases. This leads to the acidification of the soil and promotes Fe3+ to Fe2+ conversion, which plants can better uptake. This study investigated the relationship between two inhibitory transcription factors (ethylene response factors MbERF4 and MbERF72) and the H+-ATPase gene MbHA2. Two species of apple woody plants were studied: the Fe-inefficient Malus baccata and the Fe-efficient Malus xiaojinensis. Yeast one-hybrid and electrophoretic mobility shift assays showed that both MbERF4 and MbERF72 bind to the GCC cassette (AGCCGCC) of the MbHA2 promoter. Moreover, yeast two-hybrid and bimolecular fluorescence complementation assays showed that MbERF4 interacts with MbERF72. Furthermore, β-glucuronidase and luciferase reporter assays showed that the MbERF4- and MbERF72-induced repression of MbHA2 expression is synergistic. Virus-induced gene silencing of MbERF4 or MbERF72 increased MbHA2 expression, and thus lowered the rhizosphere pH in M. baccata. Consequently, the high expressions of MbERF4 and MbERF72 induced by Fe deficiency contributed to the Fe sensitivity of M. baccata. Moreover, the low expressions of MxERF4 and MxERF72 contributed to the Fe-deficiency tolerance of M. xiaojinensis via different binding conditions to the HA2 promoter. In summary, this study identified the relationship of two inhibitory transcription factors with the H+-ATPase gene and proposed a model in which ERF4 and ERF72 affect the rhizosphere pH in response to Fe deficiency., (© The Author(s) 2019. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

As sessile organisms, plants must be highly adaptable to the changing environment by modifying their growth and development. Plants rely on their underground part, the root system, to absorb water and nutrients and to anchor to the ground. The root is a highly dynamic organ of indeterminate growth with new tissues produced by root stem cells. Plants have evolved unique molecular mechanisms to fine-tune root developmental processes, during which phytohormones play vital roles. These hormones often relay environmental signals to auxin signaling that ultimately directs root development programs. Therefore, the crosstalk among hormones is critical in the root development. In this review, we will focus on the recent progresses that jasmonic acid (JA) and ethylene signaling are integrated into auxin in regulating root development of Arabidopsis thaliana and discuss the key roles of transcription factors (TFs) ethylene response factors (ERFs) and homeobox proteins in the crosstalk., (Copyright © 2020 Xu, Zhao, Cai, Mao, Miao and Xiang.)

The ability to perceive oxygen levels and adapt metabolism on the basis of its availability is vital for most eukaryotic cells. Here, we retrace the key steps that led to the identification of oxygen-sensing mechanisms in animals and plants and compare the essential features of the two strategies., (Copyright © 2019 Elsevier Ltd. All rights reserved.)