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Abscisic acid (ABA) is a drought-stress-responsive hormone that plays an important role in the stomatal activity of plant leaves. Currently, ABA glycosides have been identified in apples, but their glycosyltransferases for glycosylation modification of ABA are still unidentified. In this study, the mRNA expression of glycosyltransferase gene MdUGT73AR4 was significantly up-regulated in mature apple leaves which were treated in drought stress by Real-Time PCR. It was hypothesised that MdUGT73AR4 might play an important role in drought stress. In order to further characterise the glycosylation modification substrate of glycosyltransferase MdUGT73AR4, we demonstrated through in vitro and in vivo functional validation that MdUGT73AR4 can glycosylate ABA. Moreover, the overexpression lines of MdUGT73AR4 significantly enhance its drought stress resistance function. We also found that the adversity stress transcription factor AREB1B might be an upstream transcription factor of MdUGT73AR4 by bioinformatics, EMSA, and ChIP experiments. In conclusion, this study found that the adversity stress transcription factor AREB1B was significantly up-regulated at the onset of drought stress, which in turn positively regulated the downstream glycosyltransferase MdUGT73AR4, causing it to modify ABA by mass glycosylation and promoting the ABA synthesis pathway, resulting in the accumulation of ABA content, and displaying a stress-resistant phenotype.

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AREB/ABF (ABA response element binding) proteins in plants are essential for stress responses, while our understanding of AREB/ABFs from orchid species, important traditional medicinal and ornamental plants, is limited. Here, twelve AREB/ABF genes were identified within three orchids' complete genomes and classified into three groups through phylogenetic analysis, which was further supported with a combined analysis of their conserved motifs and gene structures. The cis-element analysis revealed that hormone response elements as well as light and stress response elements were widely rich in the AREB/ABFs. A prediction analysis of the orchid ABRE/ABF-mediated regulatory network was further constructed through cis-regulatory element (CRE) analysis of their promoter regions. And it revealed that several dominant transcriptional factor (TF) gene families were abundant as potential regulators of these orchid AREB/ABFs. Expression profile analysis using public transcriptomic data suggested that most AREB/ABF genes have distinct tissue-specific expression patterns in orchid plants. Additionally, DcaABI5 as a homolog of ABA INSENSITIVE 5 (ABI5) from Arabidopsis was selected for further analysis. The results showed that transgenic Arabidopsis overexpressing DcaABI5 could rescue the ABA-insensitive phenotype in the mutant abi5. Collectively, these findings will provide valuable information on AREB/ABF genes in orchids.

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Drought is among the most common abiotic constraints of crop growth, development, and productivity. Integrating different omics approaches offers a possibility for deciphering the metabolic pathways and fundamental mechanisms involved in abiotic stress tolerance. Here, we explored the transcriptional and post-transcriptional changes in drought-stressed tomato plants using transcriptomic and proteomic profiles to determine the molecular dynamics of tomato drought stress responses. We identified 22467 genes and 5507 proteins, among which the expression of 3765 genes and 294 proteins was significantly changed under drought stress. Furthermore, the differentially expressed genes (DEGs) and differentially abundant proteins (DAPs) showed a good correlation (0.743). The results indicated that integrating different omics approaches is promising in exploring the multilayered regulatory mechanisms of plant drought resistance. Gene ontology (GO) and pathway analysis identified several GO terms and pathways related to stress resistance, including response to stress, abiotic stimulus, and oxidative stress. The plant hormone abscisic acid (ABA) plays pivotal roles in response to drought stress, ABA-response element binding factor (AREB) is a key positive regulator of ABA signaling. Moreover, our analysis indicated that drought stress increased the abscisic acid (ABA) content, which activated AREB1 expression to regulate the expression of TAS14, GSH-Px-1, and Hsp, ultimately improving tomato drought resistance. In addition, the yeast one-hybrid assay demonstrated that the AREB1 could bind the Hsp promoter to activate Hsp expression. Thus, this study involved a full-scale analysis of gene and protein expression in drought-stressed tomato, deepening the understanding of the regulatory mechanisms of the essential drought-tolerance genes in tomato.

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Cold is a major environmental factor that restrains potato production. Abscisic acid (ABA) can enhance freezing tolerance in many plant species, but powerful evidence of the ABA-mediated signalling pathway related to freezing tolerance is still in deficiency. In the present study, cold acclimation capacity of the potato genotypes was enhanced alongside with improved endogenous content of ABA. Further exogenous application of ABA and its inhibitor (NDGA) could enhance and reduce potato freezing tolerance, respectively. Moreover, expression pattern of downstream genes in ABA signalling pathway was analysed and only ScAREB4 was identified with specifically upregulate in S. commersonii (CMM5) after cold and ABA treatments. Transgenic assay with overexpression of ScAREB4 showed that ScAREB4 promoted freezing tolerance. Global transcriptome profiling indicated that overexpression of ScAREB4 induced expression of TPS9 (trehalose-6-phosphate synthase) and GSTU8 (glutathione transferase), in accordance with improved TPS activity, trehalose content, higher GST activity and accumulated dramatically less H2 O2 in the ScAREB4 overexpressed transgenic lines. Taken together, the current results indicate that increased endogenous content of ABA is related to freezing tolerance in potato. Moreover, ScAREB4 functions as a downstream transcription factor of ABA signalling to promote cold tolerance, which is associated with increased trehalose content and antioxidant capacity.

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Abscisic acid (ABA) is a plant hormone that plays an important regulatory role in plant growth and stress response. The AREB (ABA-responsive element binding protein)/ABF (ABRE-binding factor) are important ABA-signaling components that participate in abiotic stress response. However, genome-scale analysis of ABF/AREB has not been systemically investigated in tomato. This study was conducted to identify tomato ABF/AREB family members and analyze their response to ABA and abiotic stresses. The results show that a total of 10 ABF/AREB members were identified in tomato, which are randomly distributed on five chromosomes. Domain analysis showed that these members exhibit high protein similarity, especially in the basic leucine zipper (bZIP) domain region. Subcellular localization analysis indicated that all 10 ABF/AREB members are localized in the nucleus. Phylogenetic tree analysis showed that tomato ABF/AREB genes are divided into two groups, and they are similar with the orthologs of other plants. The analysis of cis-acting elements showed that most tomato ABF/AREB genes contain a variety of hormones and stress-related elements. Expression profiles of different tissues indicated that SlABF2 and SlABF10 play an important role in fruit ripening. Finally, qRT-PCR analysis revealed that 10 tomato ABF/AREB genes respond to ABA, with SlABF3 being the most sensitive. SlABF3, SlABF5 and SlABF10 positively respond to salt and cold stresses. SlABF1, SlABF3 and SlABF10 are significantly induced under UV radiation treatment. SlABF3 and SlABF5 are significantly induced in osmotic stress. Overall, this study may provide insight into the role of tomato ABF/AREB homologues in plant response to abiotic stresses, which laid a foundation for future functional study of ABF/AREB in tomato.

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The abscisic acid (ABA)-responsive element binding protein/ABRE-binding factor (AREB/ABF) subfamily members are essential to ABA signaling pathways and plant adaptation to various environmental stresses. Nevertheless, there are no reports on AREB/ABF in jute (Corchorus L.). Here, eight AREB/ABF genes were identified in the C. olitorius genome and classified into four groups (A-D) based on their phylogenetic relationships. A cis-elements analysis showed that CoABFs were widely involved in hormone response elements, followed by light and stress responses. Furthermore, the ABRE response element was involved in four CoABFs, playing an essential role in the ABA reaction. A genetic evolutionary analysis indicated that clear purification selection affects jute CoABFs and demonstrated that the divergence time was more ancient in cotton than in cacao. A quantitative real-time PCR revealed that the expression levels of CoABFs were upregulated and downregulated under ABA treatment, indicating that CoABF3 and CoABF7 are positively correlated with ABA concentration. Moreover, CoABF3 and CoABF7 were significantly upregulated in response to salt and drought stress, especially with the application of exogenous ABA, which showed higher intensities. These findings provide a complete analysis of the jute AREB/ABF gene family, which could be valuable for creating novel jute germplasms with a high resistance to abiotic stresses.

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The INDETERMINATE DOMAIN (IDD) transcription factors mediate various aspects of plant growth and development. We previously reported that an Arabidopsis IDD subfamily regulates spatial auxin accumulation, and thus organ morphogenesis and gravitropic responses. However, its functions in stress responses are not well defined. Here, we use a combination of physiological, biochemical, molecular, and genetic approaches to provide evidence that the IDD14 cooperates with basic leucine zipper-type binding factors/ABA-responsive element (ABRE)-binding proteins (ABRE-binding factors (ABFs)/AREBs) in ABA-mediated drought tolerance. idd14-1D, a gain-of-function mutant of IDD14, exhibits decreased leaf water loss and improved drought tolerance, whereas inactivation of IDD14 in idd14-1 results in increased transpiration and reduced drought tolerance. Altered IDD14 expression affects ABA sensitivity and ABA-mediated stomatal closure. IDD14 can physically interact with ABF1-4 and subsequently promote their transcriptional activities. Moreover, ectopic expression and mutation of ABFs could, respectively, suppress and enhance plant sensitivity to drought stress in the idd14-1 mutant. Our results demonstrate that IDD14 forms a functional complex with ABFs and positively regulates drought-stress responses, thus revealing a previously unidentified role of IDD14 in ABA signaling and drought responses.

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Brassica parachinensis is a popular leafy vegetable. It is able to accumulate high concentration of Cd, however, the molecular mechanism of Cd accumulation is unknown. This study investigated the function and regulatory mechanism of the Cd-responsive metal ion transporter gene BrpHMA2. BrpHMA2 was induced by Cd stress and specifically expressed in vascular tissues, and the protein was localized in the plasma membrane. Heterologous expression of BrpHMA2 enhanced Cd accumulation and Cd sensitivity in transgenic Arabidopsis and yeast. After Cd stress, the transcriptional factors BrpNAC895 and BrpABI449, which may recognize the ABREs in the BrpHMA2 promoter, were also differentially expressed. The transcriptional regulation of BrpHMA2 was further investigated using ChIP-qPCR, EMSA and LUC reporter activity analysis employing the transient expression system of Brassica parachinensis protoplasts and tobacco leaves and the E. coli expression system. By binding to the promoter, BrpNAC895 induced the transcription of BrpHMA2. BrpABI449 might bind to the BrpHMA2 promoter or interact with BrpNAC895 to interfere with the action of BrpNAC895. The findings suggest that BrpHMA2 is a membrane-based afflux-type Cd transporter involved in the Cd2+ uptake and long-distance transport in plants. BrpNAC895 and BrpABI449, which function as the transcription activator and repressor respectively, coregulate BrpHMA2 expression.

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Oxygen (O2) plays an essential role in aerobic organisms including terrestrial insects. Under hypoxic stress, the cowpea bruchid (Callosobruchus maculatus) ceases feeding and growth. However, larvae, particularly 4th instar larvae exhibit very high tolerance to hypoxia and can recover normal growth once brought to normoxia. To better understand the molecular mechanism that enables insects to cope with low O2 stress, we performed RNA-seq to distinguish hypoxia-responsive genes in midguts and subsequently identified potential common cis-elements in promoters of hypoxia-induced and -repressed genes, respectively. Selected elements were subjected to gel-shift and transient transfection assays to confirm their cis-regulatory function. Of these putative common cis-elements, AREB6 appeared to regulate the expression of CmLPCAT and CmScylla, two hypoxia-induced genes. CmZFH, the putative AREB6-binding protein, was hypoxia-inducible. Transient expression of CmZFH in Drosophila S2 cells activated CmLPCAT and CmScylla, and their induction was likely through interaction of CmZFH with AREB6. Binding to AREB6 was further confirmed by bacterially expressed CmZFH recombinant protein. Deletion analyses indicated that the N-terminal zinc-finger cluster of CmZFH was the key AREB6-binding domain. Through in silico and experimental exploration, we discovered novel transcriptional regulatory components associated with gene expression dynamics under hypoxia that facilitated insect survival.

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Aureobasidium melanogenum P16, the high pullulan producer, had only one GATA type transcriptional activator AreA and one GATA type transcriptional repressor AreB. It was found that 2.4 g/L of (NH4)2SO4 had obvious nitrogen repression on pullulan biosynthesis by A. melanogenum P16. Removal of the AreB gene could make the disruptant DA6 produce 34.8 g/L pullulan while the P16 strain only produced 28.8 g/L pullulan at the efficient nitrogen condition. Further both removal of the native AreA gene and overexpression of the mutated AreAS628-S678 gene with non-phosphorylatable residues could render the transformant DEA12 to produce 39.8 g/L pullulan. The transcriptional levels of most of the genes related to pullulan biosynthesis in the transformant DEA12 were greatly enhanced. The mutated AreAS628-S678 was localized in the nuclei of the transformant DEA12 while the native AreA was distributed in the cytoplasm in A. melanogenum P16. This meant that nitrogen repression on pullulan biosynthesis in the transformant DEA12 was indeed significantly relieved. This was the first time to report that the GATA type transcriptional factors of nitrogen catabolite repression system could regulate pullulan biosynthesis in Aureobasidium spp.

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The core abscisic acid (ABA) signaling pathway consists of receptors, phosphatases, kinases and transcription factors, among them ABA INSENSITIVE 5 (ABI5) and ABRE BINDING FACTORs/ABRE-BINDING PROTEINs (ABFs/AREBs), which belong to the BASIC LEUCINE ZIPPER (bZIP) family and control expression of stress-responsive genes. ABI5 is mostly active in seeds and prevents germination and post-germinative growth under unfavorable conditions. The activity of ABI5 is controlled at transcriptional and protein levels, depending on numerous regulators, including components of other phytohormonal pathways. ABFs/AREBs act redundantly in regulating genes that control physiological processes in response to stress during vegetative growth. In this review, we focus on recent reports regarding ABI5 and ABFs/AREBs functions during abiotic stress responses, which seem to be partially overlapping and not restricted to one developmental stage in Arabidopsis and other species. Moreover, we point out that ABI5 and ABFs/AREBs play a crucial role in the core ABA pathway's feedback regulation. In this review, we also discuss increased stress tolerance of transgenic plants overexpressing genes encoding ABA-dependent bZIPs. Taken together, we show that ABI5 and ABFs/AREBs are crucial ABA-dependent transcription factors regulating processes essential for plant adaptation to stress at different developmental stages.

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Drought stress hinders the growth and development of crop plants and ultimately its productivity. It is expected that drought stress will be frequent and intense in the future due to drastic changes in the global climate. It is necessary to make crop plants more resilient to drought stress through various techniques; drought-hardening is one of them. Defining various metabolic strategies used by tobacco plants to confer drought tolerance will be important for maintaining plant physiological functions, but studies addressing this topic are limited. This study was designed to elucidate the drought tolerance and adaptation strategies used by tobacco plants via the application of different circular drought-hardening cycles (control: no drought-hardening, T1: one cycle of drought hardening, T2: two cycles of drought-hardening, and T3: three cycles of drought-hardening) to two tobacco varieties namely Honghuadajinyuan (H) and Yun Yan-100 (Y). The results revealed that drought-hardening decreased the fresh and dry biomass of the tobacco plants. The decrease was more pronounced in the T3 treatment for both H (23 and 29%, respectively) and Y (26 and 31%, respectively) under drought stress. The MDA contents, especially in T1 and T2 in both varieties, were statistically similar compared with control under drought stress. Similarly, higher POD, APX, and GR activities were observed, especially in T3, and elevated amounts of AsA and GSH were also observed among the different circular drought-hardening treatments under drought stress. Thus circular drought-hardening mitigated the oxidative damage by increasing the antioxidant enzyme activities and elevated the content of antioxidant substances, a key metabolic strategy under drought stress. Similarly, another important plant metabolic strategy is the osmotic adjustment. Different circular drought-hardening treatments improved the accumulation of proline and soluble sugars contents which contributed to osmoregulation. Finally, at the molecular level, circular drought-hardening improved the transcript levels of antioxidant enzyme-related genes (CAT, APX1, and GR2), proline and polyamines biosynthesis-related genes (P5CS1 and ADC2), and ABA signaling (SnRK2), and transcription factors (AREB1 and WRKY6) in response to drought stress. As a result, circular drought-hardening (T2 and T3 treatments) promoted tolerance to water stress via affecting the anti-oxidative capacity, osmotic adjustment, and regulation of gene expression in tobacco.

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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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BACKGROUND: Drought stress is the most harmful one among other abiotic stresses with negative impacts on crop growth and development. Drought-hardening is a feasible and widely used method in tobacco seedlings cultivation. It has gained extensive interests due to its role in improving drought tolerance. This research aimed to investigate the role of drought-hardening and to unravel the multiple mechanisms underlying tobacco drought tolerance and adaptation. RESULTS: This study was designed in which various drought-hardening treatments (CK (no drought-hardening), T1 (drought-hardening for 24 h), T2 (drought-hardening for 48 h), and T3 (drought-hardening for 72 h)) were applied to two tobacco varieties namely HongHuaDaJinYuan (H) and Yun Yan-100 (Y). The findings presented a complete framework of drought-hardening effect at physiological, biochemical, and gene expression levels of the two tobacco varieties under drought stress. The results showed that T2 and T3 significantly reduced the growth of the two varieties under drought stress. Similarly, among the various drought-hardening treatments, T3 improved both the enzymatic (POD, CAT, APX) and non-enzymatic (AsA) defense systems along with the elevated levels of proline and soluble sugar to mitigate the negative effects of oxidative damage and bringing osmoregulation in tobacco plants. Finally, the various drought-hardening treatments (T1, T2, and T3) showed differential regulation of genes expressed in the two varieties, while, particularly T3 drought-hardening treatment-induced drought tolerance via the expression of various stress-responsive genes by triggering the biosynthesis pathways of proline (P5CS1), polyamines (ADC2), ABA-dependent (SnRK2, AREB1), and independent pathways (DREB2B), and antioxidant defense-related genes (CAT, APX1, GR2) in response to drought stress. CONCLUSIONS: Drought-hardening made significant contributions to drought tolerance and adaptation in two tobacco variety seedlings by reducing its growth and, on the other hand, by activating various defense mechanisms at biochemical and molecular levels. The findings of the study pointed out that drought-hardening is a fruitful strategy for conferring drought tolerance and adaptations in tobacco. It will be served as a useful method in the future to understand the drought tolerance and adaptation mechanisms of other plant species. Drought-hardening improved drought tolerance and adaptation of the two tobacco varieties. T1 indicates drought-hardening for 24 h, T2 indicates drought-hardening for 48 h, T3 indicates drought-hardening for 72 h.

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bZIP transcription factors have been reported to be involved in many different biological processes in plants. The ABA (abscisic acid)-dependent AREB/ABF-SnRK2 pathway has been shown to play a key role in the response to osmotic stress in model plants. In this study, a novel bZIP gene, FtbZIP5, was isolated from tartary buckwheat, and its role in the response to drought and salt stress was characterized by transgenic Arabidopsis. We found that FtbZIP5 has transcriptional activation activity, which is located in the nucleus and specifically binds to ABRE elements. It can be induced by exposure to PEG6000, salt and ABA in tartary buckwheat. The ectopic expression of FtbZIP5 reduced the sensitivity of transgenic plants to drought and high salt levels and reduced the oxidative damage in plants by regulating the antioxidant system at a physiological level. In addition, we found that, under drought and salt stress, the expression levels of several ABA-dependent stress response genes (RD29A, RD29B, RAB18, RD26, RD20 and COR15) in the transgenic plants increased significantly compared with their expression levels in the wild type plants. Ectopic expression of FtbZIP5 in Arabidopsis can partially complement the function of the ABA-insensitive mutant abi5-1 (abscisic acid-insensitive 5-1). Moreover, we screened FtSnRK2.6, which might phosphorylate FtbZIP5, in a yeast two-hybrid experiment. Taken together, these results suggest that FtbZIP5, as a positive regulator, mediates plant tolerance to salt and drought through ABA-dependent signaling pathways.

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Plants are subjected to a variety of abiotic stresses during their lifetime, and drought and salt stress are some of the main causes of reduced crop yields. Previous studies have shown that AREB/ABFs within bZIP transcription factors are involved in plant drought and salt stress responses in an ABA-dependent manner. However, the properties and functions of AREB/ABFs in Fagopyrum tataricum, a cereal with good resistance to abiotic stresses, are poorly understood. In this study, a gene encoding an AREB/ABF, designated FtbZIP83, was first isolated from Tartary buckwheat. Expression analysis in Tartary buckwheat indicated that FtbZIP83 was significantly induced by abscisic acid (ABA), NaCl and polyethylene glycol (PEG). The overexpression of FtbZIP83 in Arabidopsis resulted in increased drought/salt tolerance, which was attributed not only to higher proline (Pro) contents and antioxidant enzyme activity in transgenic lines compared with controls but also to the lower reactive oxygen species (ROS) accumulation and malondialdehyde (MDA) content. In addition, we found that FtbZIP83 was able to respond to drought and salt stress by upregulating the transcript abundance of downstream ABA-inducible gene. Furthermore, promoter sequence analysis showed that ABREs were present, and the activity of the FtbZIP83 promoter in transgenic Arabidopsis after drought stress was significantly higher than that under normal conditions. Based on the potential signalling pathways involved in AREB/ABFs, we also screened for the interaction protein FtSnRK2.6/2.3, which may phosphorylate FtbZIP83. Collectively, these results provide evidence that FtbZIP83, as a positive regulator, responds to drought/salt stress via an ABA-dependent signalling pathway composed of SnRK2-AREB/ABF.

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Bacterial diversity and antimicrobial resistance patterns among the indicator organism Escherichia coli were monitored in wastewater samples collected over one year from a hospital (HW), a community (CW) and the receiving urban (UW) wastewater treatment plant (WWTP). We compared levels of antibiotic resistance in the different types of wastewater, and identified whether resistant strains were endemic in the wastewater system. If so, implementation of local treatment at certain resistance hotspots (e.g. hospital outlets) could be used to decrease the amount of resistant bacteria in the wastewater. E. coli from HW (n = 2644), CW (n = 2525) and UW (n = 2693) were analyzed by biochemical phenotyping (PhenePlate System) and antimicrobial susceptibility testing to nine antibiotics (AREB System). The phenotypic diversities of the total E. coli populations were similar for all three sites (Simpson's Diversity index, Di = 0.973), however for individual samples, HW showed low diversities (Median Di = 0.800) and the E. coli flora was often dominated by strains that may have originated from the fecal flora of single individuals. The diversities in CW samples was higher (Median Di = 0.936), and UW samples showed similar diversities as the whole collection of isolates (Median Di = 0.971). Resistance to at least one of the nine antibiotics was observed in 45% of the HW isolates, 44% of CW isolates, and 33% of UW isolates. Resistance to gentamicin and chloramphenicol was uncommon (3.2 and 5.3%, respectively), whereas resistance to tetracycline and ampicillin was most common (24% and 31%, respectively). Extended-spectrum beta-lactamase-producing E. coli (ESBL-EC) were more common in HW (11.5%) and in CW (6.9%) compared to UW (3.7%). A high diversity (Di = 0.974) was observed among ESBL-EC isolates from UW (n = 99), indicating absence of any clonal structure among these isolates. Common PhP types of ESBL-EC often dominated in each HW sample, but were not identified across different samples, whereas ESBL-EC in CW showed low diversity (Di = 0.857) and were dominated by a specific PhP type that was found across almost all CW samples. The antibiotic resistance rates were highest in hospital wastewater, but surprisingly they were also high in the studied community wastewater, compared to the urban wastewater. The relative contribution of HW seemed low in terms of dissemination of antibiotic resistant bacteria to the WWTP.

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In Aspergillus nidulans, nitrogen and carbon metabolism are under the control of wide-domain regulatory systems, including nitrogen metabolite repression, carbon catabolite repression and the nutrient starvation response. Transcriptomic analysis of the wild type strain grown under different combinations of carbon and nitrogen regimes was performed, to identify differentially regulated genes. Carbon metabolism predominates as the most important regulatory signal but for many genes, both carbon and nitrogen metabolisms coordinate regulation. To identify mechanisms coordinating nitrogen and carbon metabolism, we tested the role of AreB, previously identified as a regulator of genes involved in nitrogen metabolism. Deletion of areB has significant phenotypic effects on the utilization of specific carbon sources, confirming its role in the regulation of carbon metabolism. AreB was shown to regulate the expression of areA, tamA, creA, xprG and cpcA regulatory genes suggesting areB has a range of indirect, regulatory effects. Different isoforms of AreB are produced as a result of differential splicing and use of two promoters which are differentially regulated by carbon and nitrogen conditions. These isoforms are likely to be functionally distinct and thus contributing to the modulation of AreB activity.

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In our previous work, gene PPP1R11 (protein phosphatase 1 regulatory subunit 11) was significantly expressed in pigs after Streptococcus suis 2 (SS2) challenged. This study firstly confirmed that SS2 induced significant expression of PPP1R11 gene in porcine alveolar macrophage (PAM) cells, and apoptosis of PAM cells were observed. After that, the core promoter of porcine PPP1R11 was identified and its transcription factor AREB6 which significantly regulated PPP1R11. We also characterized that the PPP1R11 gene is a target of miR-34a. Further, we found that PPP1R11 helped to inhibit apoptosis of PAM cells under SS2 infecting, through transcription factor AREB6 was negatively correlated with apoptosis whereas miR-34a was positively correlated. Those findings provide a functional connection among the transcription factor AREB6, miR-34a, PPP1R11 gene and apoptosis of PAM cells in the pathogenesis of the SS2 infection.

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Abscisic acid (ABA) plays crucial roles in plant development and adaption to environmental stresses. The ABA-responsive element binding protein/ABRE-binding factor and ABA INSENSITIVE 5 (AREB/ABF/ABI5) gene subfamily members, which belong to the basic domain/leucine zipper (bZIP) transcription factors family, participate in the ABA-mediated signaling pathway by regulating the expression of their target genes. However, information about potato (Solanum tuberosum) AREB/ABF/ABI5 subfamily members remains scarce. Here, seven putative AREB/ABF/ABI5 members were identified in the potato genome. Sequences alignment revealed that these members shared high protein sequence similarity, especially in the bZIP region, indicating that they might possess overlapping roles in regulating gene expression. Subcellular localization analysis illustrated that all seven AREB/ABF/ABI5 members were localized in the nucleus. Transactivation activity assays in yeast demonstrated that these AREB/ABF/ABI5 members possessed distinct transcriptional activity. Electrophoretic mobility shift assays (EMSA) confirmed that all of these AREB/ABF/ABI5 members could have an affinity to ABRE in vitro. The expression patterns of these AREB/ABF/ABI5 genes showed that they were in response to ABA or osmotic stresses in varying degrees. Moreover, most AREB/ABF/ABI5 genes were induced during stolon swelling. Overall, these results provide the first comprehensive identification of the potato AREB/ABF/ABI5 subfamily and would facilitate further functional characterization of these subfamily members in future work.

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