SPS Gene Research Articles

Response mechanism of major secondary metabolites of Polygonatum kingianum to selenium nanoparticles

Selenium nanoparticles (SeNPs) can be absorbed by plants, thereby affecting plant physiological activity, regulating gene expression, and altering metabolite content. However, the molecular mechanisms by which exogenous selenium affects Polygonatum kingianum coll.et Hemsl plant secondary metabolites remain unclear. In this study, we exposed P. kingianum plants to SeNPs at 0, 10, 25, and 50 mg/L concentrations. Joint physiological, metabolomic, and transcriptomic analyses were performed to reveal the response mechanisms of major secondary metabolites of P. kingianum to SeNPs. Our data shows that under the treatment of 25 mg/L, the photosynthetic electron transfer rate of plants significantly increases and the carbon-nitrogen ratio significantly decreases. In parallel, the main active components, polysaccharides and saponins, showed a significant increase in content, while flavonoid content decreased. SeNPs affect polysaccharide accumulation mainly through up-regulation of SPS, UGPase, AGPase, UTP, and SUS genes in starch and sucrose metabolic pathways. The accumulation of saponins was affected by upregulating genes in the sesquiterpenoid and triterpenoid biosynthesis pathways, including PAD, ADH, PK, and GS. The accumulation of flavonoids was mainly regulated by metabolic pathways such as flavonoid biosynthesis, isoflavonoid biosynthesis, and the biosynthesis of phenylpropanoids. In summary, this study reveals the key metabolic pathways affected by SeNPs in the main secondary metabolic products of P. kingianum.

Investigation on biofilm composition and virulence traits of S. pseudintermedius isolated from infected and colonized dogs.

Staphylococcus pseudintermedius, which is part of the skin microbiome of dogs, causes a variety of opportunistic infections. These infections may become more difficult to treat due to the formation of biofilm. The capacity of S. pseudintermedius to form biofilm, as well as the associated genes, has not been elucidated. This study evaluated the production and composition of S. pseudintermedius biofilm. Samples were collected from both infected dogs and asymptomatic dogs. Isolates were identified using mass spectrometry and Multiplex-PCR. Biofilm production and composition were assessed using a quantitative microtiter plate assay. The presence of ica operon genes and sps genes was investigated using conventional PCR. The investigation of Agr type and virulence genes was conducted in silico on 24 sequenced samples. All strains could produce strong biofilms, with most of the isolates presenting a polysaccharide biofilm. 63.6% of the isolates carried the complete ica operon (ADBC). All samples showed the presence of the genes spsK, spsA, and spsL, while the distribution of other genes varied. Agr type III was the most prevalent (52.2%). All sequenced samples carried the cytotoxins hlb, luk-S, luk-F, as well as the exfoliative toxins siet and se_int. No isolate displayed other exfoliative toxins. Only LB1733 presented a set of different enterotoxins (sea, seb, sec_canine, seh, sek, sel, and seq). Our findings suggest that S. pseudintermedius is a strong producer of biofilm and carries virulence genes.

Functional Analysis of the Apple SPS Gene Family in Response to Abiotic Stresses

Functional Analysis of the Apple SPS Gene Family in Response to Abiotic Stresses

Comparative transcriptome analysis of gene responses of salt-tolerant and salt-sensitive rice cultivars to salt stress

Salt stress is one unfavorable factor of global climate change that adversely affects rice plant growth and yield. To identify novel salt-tolerant genes and new varieties of salt-tolerant rice, a better understanding of the molecular regulation mechanism of salt tolerance in rice is needed. In this study we used transcriptome analyses to examine changes in gene expression of salt-tolerant and salt-sensitive rice plants. The salt-tolerant cultivar HH11 and salt-sensitive cultivar IR29 were treated with 200 mM NaCl solution for 0 h, 6 h, 24 h and 48 h at the three leaf stage. Physiological parameters and transcriptome were measured and analyzed after each treatment. Activity of SOD and POD, as well as the MDA and protein content of the two rice cultivars generally increased with increasing time of exposure to NaCl. Meanwhile, the APX activity first increased, then decreased in both cultivars, with maximum values seen at 6 h for IR29 and at 24 h for HH11. The GR and GPX activity of HH11 were stronger than that of IR29 in response to salt stress. The H2O2 content first increased at 0–6 h, then decreased at 6–24 h, and then increased again at 24–48 h under salt stress. Compared with IR29, SOD, POD and APX activity of HH11 was more sluggish in response to salt stress, reaching the maximum at 24 h or 48 h. The MDA, H2O2 and proline content of HH11 was lower than that of IR29 under salt stress. Relative to untreated HH11 plants (0 h) and those exposed to salt for 6 h, 24 h, and 48 h (H0-H6, H0-H24 and H0-H48), 7462, 6363 and 6636, differentially expressed genes (DEGs), respectively, were identified. For IR29, the respective total DEGs were 7566, 6075 and 6136. GO and KEGG enrichment analysis showed that metabolic pathways related to antioxidative responses and osmotic balance played vital roles in salt stress tolerance. Sucrose and starch metabolism, in addition to flavonoid biosynthesis and glutathione metabolism, showed positive responses to salt stress. Expression of two SPS genes (LOC_Os01g69030 and LOC_Os08g20660) and two GST genes (LOC_Os06g12290 and LOC_Os10g38740) was up-regulated in both HH11 and IR29, whereas expression of LOC_Os09g12660, a glucose-1-phosphate adenylyltransferase gene, and two SS genes (LOC_Os04g17650 and LOC_Os04g24430) was up-regulated differential expression in HH11. The results showed that HH11 had more favorable adjustment in antioxidant and osmotic activity than IR29 upon exposure to salt stress, and highlighted candidate genes that could play roles in the function and regulation mechanism of salt tolerance in rice.

Antioxidant, antibacterial and antileishmanial potential of Micromeria nervosa extracts and molecular mechanism of action of the bioactive compound.

This study aimed to determine the antibacterial and antileishmanial potential of Micromeria nervosa extracts. The identification of the antileishmanial compound and the study of its molecular mechanism of action have also been undertaken. Ethanol extract showed high polyphenol content and diethyl ether extract exhibited high DPPH scavenging and low beta-carotene bleaching activity (IC50=13.04±0.99µg/mL and 200.18±3.32µg/mL, respectively). However, diethyl ether extract displayed high antibacterial activity against Gram-positive strains including methicillin-resistant Staphylococcus aureus (MIC=31.25µg mL-1), Staphylococcus aureus ATCC6538 (MIC=62.5µg mL-1) and Listeria monocytogenes ATCC 19115 (MIC=125µg mL-1) as well as high antileishmanial activity against the promastigote forms of L. infantum and L. major (IC50=11.45µg mL-1 and IC50=14.53µg mL-1, respectively). The active compound was purified using bioassay-guided fractionation and thin layer chromatography, and identified as ursolic acid using high performance liquid chromatography coupled with a photodiode array and mass spectrometry. The purified compound was strongly inhibitory against the promastigote and amastigote forms of L. infantum and L. major (IC50=5.87µg mL-1 and 6.95mL-1, versus 9.56µg mL-1 and 10. 68µg mL-1, respectively) without overt cytotoxicity against Raw 264.7 macrophage cells (SI=13.53 and 11.43, respectively). The commercial compound (ursolic acid) showed similar activity against amastigotes and promastigotes forms of L. infantum and L. major. Moreover, its molecular mode of action against leishmaniasis seems to involve the expression of the ODC and SPS genes involved in thiol pathway. Extracts of Micromeria nervosa can be considered as a potential alternative to antimicrobial and antileishmanial drugs.

Cloning and Expression Analysis of Tomato <i>SlSPS1</i> Gene

Sucrose is the main product of plant photosynthesis and participates in many physiological and biochemical reactions of plants. Sucrose phosphate synthase is one of the key rate-limiting enzymes necessary for sucrose to enter various metabolic pathways, and its activity directly reflects the ability of sucrose synthesis in plants. In order to study the mechanism of sucrose synthesis in tomato, this study cloned a sucrose phosphate synthase gene from tomato pulp and named it  SlSPS1 . Through bioinformatics analysis, it was found that its cDNA is 3488bp in length, encoding 1054 amino acids, and there are 3 functional domain. There are 4  SPS  genes in tomato, and their homology is relatively high. In Salicaceae crops, SlSPS1 protein is closely related to potatoes, peppers and eggplants. The results of tissue-specific analysis found that  SlSPS1  was expressed in all tomato tissues, among which the expression was relatively high in the seedling stage and different development stages of the fruit. In order to further study the mechanism of SlSPS1 in tomato growth and sucrose accumulation, an overexpression and knockout vector of  SlSPS1  was constructed and transformed into Micro-Tom to obtain transgenic positive lines. Analysis of the expression level of  SlSPS1  on the obtained transgenic lines showed that the expression levels of the overexpression lines at the seedling stage, fruit green ripe stage and ripening stage were significantly up-regulated compared with the wild type, and the enzyme activity and sucrose content increased. Compared with the wild type, the expression of  SlSPS1  at the seedling stage, green ripe stage and ripening stage of the knockout line was significantly down-regulated, and the enzyme activity and sucrose content were reduced. As for the mechanism of  SlSPS1  in tomato growth and fruit sucrose accumulation, functional verification is needed in the future.

Identification, characterisation, and expression profile analysis of the sucrose phosphate synthase gene family in pineapple (Ananas comosus)

ABSTRACT Sucrose plays a crucial role in plant growth and development. Sucrose phosphate synthase (SPS, EC 2.4.1.14) is a key rate-limiting enzyme in the sucrose metabolism of plants. To date, the genome-wide identification, characterisation, and expression profile analysis of SPS gene families have been reported in many species but not in pineapple (Ananas comosus). In this study, five SPS genes (AcSPS1–5), which contained sucrose synthase, glucosyltransferase, and SPP-like conserved domains, were identified. The phylogenetic tree indicated that these AcSPS genes were divided into three clades, i.e. A, B, and C. The spatiotemporal expression pattern of AcSPS gene families were first examined in pineapple. Among all tissues, AcSPS2 had the highest expression in flesh. Meanwhile, AcSPS2 expression was significantly upregulated during fruit development. Furthermore, AcSPS2 expression, SPS activity, and sucrose content consistently increased with fruit development. These results may indicate that AcSPS2 played a major role in sucrose metabolism during fruit development. AcSPS5 was strongly expressed in the peduncle, pericarp, and core. On the basis of its abundant expression, AcSPS5 was speculated to play an important role in plant growth.

Heterologous expression of Vitis vinifera SNF1-related kinase 1.1 gene in Arabidopsis akin10 mutant reveals sthe signaling regulatory network of sucrose metabolism

Grapevine (Vitis vinifera L.) is the widely cultivated important fruit crop. The regulation of sucrose metabolism is relevant for the quality improvement of grape berry. Despite the fact that SnRK1 has been suggested to be a pivotal protein in sugar sensing and signal transduction, it remains unknown how Vitis vinifera SNF1-related kinase 1 (VvSnRK1) regulates sucrose metabolism. To investigate the exact regulatory pathway of VvSnRK1.1 in sucrose metabolism, VvSnRK1.1 gene from Cabernet Sauvignon grape berries was isolated, and then VvSnRK1.1-GFP was transformed into wild type and akin10 mutant (AtSnRK1.1 mutant type) Arabidopsis thaliana, respectively. The results suggested that the overexpression of VvSnRK1.1 transformed into wild type Arabidopsis thaliana increased ABA, glucose and fructose contents, but reduced sucrose accumulation. Furthermore, overexpression of VvSnRK1.1 up-regulated the expression of SuSy, SPS and ABA-responsive gene ABI3, whilst down-regulated all INVs (CWINV, CINV and VINV) expression. Meantime, The cross-talk between sucrose and ABA promoted the expression of INVs and SuSy, while ABA could make up for the inhibitory effect of glucose on INVs and SuSy expression. Phosphated glucose, ABA and their crosstalks up-regulated HXK, SPS and ABI3 expression. Taken together, these results demonstrate the central role of VvSnRK1.1 in regulating sucrose metabolism and its involved signaling pathways.

Identification of genes associated with soluble sugar and organic acid accumulation in 'Huapi' kumquat (Fortunella crassifolia Swingle) via transcriptome analysis.

The levels and ratios of sugar and acid are important contributors to fruit taste. Kumquat is one of the most economically important citrus crops, but information on the soluble sugar and organic acid metabolism in kumquat is limited. Here, two kumquat varieties - 'Rongan' (RA) and its mutant 'Huapi' (HP) - were used to assess soluble sugar and organic acid accumulation and the related genes. Soluble sugars include sucrose, glucose and fructose, while malate, quinic acid and citrate are the dominant organic acids in the fruits of both kumquat varieties. HP accumulated more sugars but fewer organic acids than did RA. Transcriptome analysis revealed 63 and 40 differentially expressed genes involved in soluble sugar and organic acid accumulation, respectively. The genes associated with sugar synthesis and transport, including SUS, SPS, TST, STP and ERD6L, were up-regulated, whereas INVs, FRK and HXK genes related to sugar degradation were down-regulated in HP kumquat. For organic acids, the up-regulation of PEPC and NAD-MDH could accelerate malate accumulation. In contrast, high expression of NAD-IDH and GS resulted in citric acid degradation during HP fruit development. Additionally, the PK, PDH, PEPCK and FBPase genes responsible for the interconversion of soluble sugars and organic acids were also significantly altered in the early development stages in HP. The high sugar accumulation in HP fruit was associated with up-regulation of SUS, SPS, TST, STP and ERD6L genes. The PEPCK, PEPC, NAD-MDH, NADP-IDH, GS and FBPase genes played important roles in acid synthesis and degradation in HP kumquat. These findings provide further insight into understanding the mechanisms underlying metabolism of sugars and organic acids in citrus. © 2021 Society of Chemical Industry.

Construction of a Type-I Metanotroph with Reduced Capacity for Glycogen and Sucrose Accumulation

Mutant strains of the halotolerant type-I methanotroph Methylotuvimicrobium alcaliphilum 20Z with an inactivated sps gene, which encodes sucrose phosphate synthase, and the deletion of a gene cluster for the synthesis and degradation of glycogen were obtained. Blockage of the synthesis of sucrose and glycogen increased the protein content in cells but slightly reduced the growth rate of the methanotroph grown on methane. It is shown that relatively stable methanotroph growth is possible without synthesis of the storage carbon compounds.

The sps Genes Encode an Original Legionaminic Acid Pathway Required for Crust Assembly in Bacillus subtilis.

The crust is the outermost spore layer of most Bacillus strains devoid of an exosporium. This outermost layer, composed of both proteins and carbohydrates, plays a major role in the adhesion and spreading of spores into the environment. Recent studies have identified several crust proteins and have provided insights about their organization at the spore surface. However, although carbohydrates are known to participate in adhesion, little is known about their composition, structure, and localization. In this study, we showed that the spore surface of Bacillus subtilis is covered with legionaminic acid (Leg), a nine-carbon backbone nonulosonic acid known to decorate the flagellin of the human pathogens Helicobacter pylori and Campylobacter jejuni We demonstrated that the spsC, spsD, spsE, spsG, and spsM genes of Bacillus subtilis are required for Leg biosynthesis during sporulation, while the spsF gene is required for Leg transfer from the mother cell to the surface of the forespore. We also characterized the activity of SpsM and highlighted an original Leg biosynthesis pathway in B. subtilis Finally, we demonstrated that Leg is required for the assembly of the crust around the spores, and we showed that in the absence of Leg, spores were more adherent to stainless steel probably because of their reduced hydrophilicity and charge.IMPORTANCEBacillus species are a major economic and food safety concern of the food industry because of their food spoilage-causing capability and persistence. Their persistence is mainly due to their ability to form highly resistant spores adhering to the surfaces of industrial equipment. Spores of the Bacillus subtilis group are surrounded by the crust, a superficial layer which plays a key role in their adhesion properties. However, knowledge of the composition and structure of this layer remains incomplete. Here, for the first time, we identified a nonulosonic acid (Leg) at the surfaces of bacterial spores (B. subtilis). We uncovered a novel Leg biosynthesis pathway, and we demonstrated that Leg is required for proper crust assembly. This work contributes to the description of the structure and composition of Bacillus spores which has been under way for decades, and it provides keys to understanding the importance of carbohydrates in Bacillus adhesion and persistence in the food industry.

Establishment and application of a loop-mediated isothermal amplification method with double-stranded displacement probes to quantify the genetically modified rice M12 event

For the purpose of supervision and academic research on GMO, it was necessary to establish a simple and effective on-site qualitative and quantitative method for GMO detection. In this paper, double-stranded displacement probes were first designed to monitor the quantitative LAMP amplification, and calcein was used effectively in LAMP reaction for qualitative measurement. High specificity of the methods was identified by testing 16 crops. The rice endogenous gene SPS and M12 event-specific gene can both be quantified in a wide dynamic range (200–20,000 copies). The LOD and LOQ of both genes were 20 and 200 copies, respectively. When the methods were used to analyze rice samples, 0.5% (w/w) of the GM rice M12 event could be quantified accurately and 0.1% (w/w) could be detected qualitatively. These results indicated that the developed methods were specific, sensitive and repeatable, and proven to be an efficient alternative to real-time PCR. Moreover, the developed methods were more suitable for the reliable quantification in poor-equipped laboratories or on-site detection.

Enhanced production of sucrose in the fast-growing cyanobacterium Synechococcus elongatus UTEX 2973

Cyanobacteria are attractive microbial hosts for production of chemicals using light and CO2. However, their low productivity of chemicals is a major challenge for commercial applications. This is mostly due to their relatively slow growth rate and carbon partitioning toward biomass rather than products. Many cyanobacterial strains synthesize sucrose as an osmoprotectant to cope with salt stress environments. In this study, we harnessed the photosynthetic machinery of the fast-growing cyanobacterium Synechococcus elongatus UTEX 2973 to produce sucrose under salt stress conditions and investigated if the high efficiency of photosynthesis can enhance the productivity of sucrose. By expressing the sucrose transporter CscB, Synechococcus 2973 produced 8 g L−1 of sucrose with a highest productivity of 1.9 g L−1 day−1 under salt stress conditions. The salt stress activated the sucrose biosynthetic pathway mostly via upregulating the sps gene, which encodes the rate-limiting sucrose-phosphate synthase enzyme. To alleviate the demand on high concentrations of salt for sucrose production, we further overexpressed the sucrose synthesis genes in Synechococcus 2973. The engineered strain produced sucrose with a productivity of 1.1 g L−1 day−1 without the need of salt induction. The engineered Synechococcus 2973 in this study demonstrated the highest productivity of sucrose in cyanobacteria.

Comparative analysis of primary metabolites and transcriptome changes between ungrafted and pumpkin-grafted watermelon during fruit development.

Grafting has been reported as a factor that influences fruit quality. However, a comprehensive study of the metabolic profile related to fruit quality and the underlying molecular mechanism in grafted watermelon has not been carried out. Metabolomics and transcriptome analysis were performed on both pumpkin-grafted watermelon and ungrafted watermelon at different developmental stages. In total, 56 primary metabolites were identified with either high or low abundance between ungrafted and pumpkin-grafted watermelon. The results indicated that ornithine, arginine, lysine (amino acids), glucose, sucrose, glucosamine (sugars), malic acid, fumaric acid and succinic acid (organic acids) were among the dominant metabolites influencing fruit quality. Additionally, comparative RNA sequence analysis on grafted and ungrafted watermelon yielded 729, 174, 128 and 356 differentially expressed genes at 10, 18, 26 and 34 days after pollination (DAP), respectively. Functional annotations of these genes indicated that grafting significantly altered the biological and metabolic processes related to fruit quality. Our comparative metabolomics and transcriptome analysis revealed that FBA2, FK, SuSy, SPS, IAI, AI and sugar transporter gene (SWT3b) might play a central role in the accumulation of glucose and sucrose, whereas higher malic acid content was attributed to high down regulation of ALMT13 and ALMT8 in pumpkin-grafted watermelon. Changes in the ornithine, glutamine, alanine, tyrosine, valine, asparagine, phenylalanine, arginine and tryptophan contents were consistent with the transcript level of their metabolic genes such as NAOD, GS, AGT, TaT, aDH1, OGDH, aDC, 4CL 1, PaL, CaT and two nitrate transporter genes (NRT1) in pumpkin-grafted watermelon. This study provides the basis for understanding the graft-responsive changes in the metabolic profile and regulatory mechanism related to fruit quality.

The flower to fruit transition in Citrus is partially sustained by autonomous carbohydrate synthesis in the ovary

Why evergreen fruit tree species accumulate starch in the ovary during flower bud differentiation in spring, as deciduous species do during flower bud dormancy, is not fully understood. This is because in evergreen species carbon supply is assured by leaves during flower development. We suggest the existence of an autonomous mechanism in the flowers which counteracts the competition for photoassimilates with new leaves, until they become source organs. Our hypothesis is that starch accumulated during Citrus ovary ontogeny originates from 1) its own photosynthetic capacity and 2) the mobilization of reserves.Through defoliation experiments, we found that ovaries accumulate starch during flower ontogeny using a dual mechanism: 1) the autotrophic route of source organs activating Rubisco (RbcS) genes expression, and 2) the heterotrophic route of sink organs that hydrolyze sucrose in the cytosol. Defoliation 40 days before anthesis did not significantly reduce ovary growth, flower abscission or starch concentration up to 20 days after anthesis (i.e. 60 days later). Control flowers activated the energy depletion signaling system (i.e. SnRK1) and RbcS gene expression around athesis. Defoliation accelerated and boosted both activities, increasing SPS gene expression (sucrose synthesis), and SUS1, SUS3 and cwINV (sucrose hydrolysis) to maintain a glucose threshold which satisfied its need to avoid abscission.

Mutation studies of the gene encoding YuiC, a stationary phase survival protein in Bacillus subtilis

Aims: YuiC is a stationary phase survival (Sps) protein from the Firmicute Bacillus subtilis that possesses muralytic activity to cleave bacterial cell-wall peptidoglycan. It has a small lytic transglycosylase (MltA) fold analogous to the resuscitation promoting factors (Rpfs) of Actinobacteria which have a hybrid of a mini lysozyme and soluble lytic transglycosylase (Slt35/70) fold. The present study aimed at identifying key residues of YuiC/Sps that are catalytically active and studying the effect of B. subtilis cell growth upon sps/yuiC deletion. Methodology & Results: Four forms of mutated yuiC were created through Site-directed, Ligase-Independent Mutagenesis Polymerase Chain Reaction (SLIM PCR) that include the substitutions of D129A, D151A, D162A and K102A. These individual mutated yuiC genes were cloned and expressed in the Escherichia coli BL21 (DE3) expression system and subsequently purified to homogeneity using affinity, cation exchange and size exclusion chromatography. The D129A variant was shown to be insoluble, indicating its role in maintaining the right protein folding of YuiC. The remaining three variants resulted in soluble proteins but were inactive on zymograms indicating that they may be responsible for catalysis. B. subtilis cells harbouring individual sps genes (yuiC, yabE, yocH and yorM) knocked out showed stationary phase defects and altered colony morphologies compared to the wild type. Conclusion: This study has identified the key residues involved in catalysis of YuiC, which are the D151, D162 and K102. These are conserved in Sps domains. The catalytic mechanism of YuiC is similar to the mechanism reported for Neisseria gonorrhoeae MltA. sps/yuiC knock outs have implied that each sps/yuiC has a significant role on B. subtilis late growth stage. Significance and Impact of study: The B. subtilis YuiC/Sps model has given an insight into Sps functions in the final growth stage of the Firmicutes, which members include etiologic agents of anthrax, botulism and listeriosis. Inhibition of Sps protein may inactivate pathogen replication and facilitate entrance into a non-contagious dormant sporulation stage.

Genome-wide Analysis and Expression Profiling of SPS Gene Family in Brassica nupus L.

Genome-wide Analysis and Expression Profiling of SPS Gene Family in <i>Brassica nupus</i> L.

Cloning, Expression and Genetic Transformation of Sucrose Phosphate Synthase (Sps) Gene in Saccharum Spontaneum L.

AbstractSucrose phosphate synthase (SPS) is a key enzyme catalyzing sucrose metabolism in plants. In this study, we isolated the SPS cDNA from Saccharum spontaneum and designated as SsSPS (GenBank accession no. MF398541). The full-length of SsSPS cDNA was 4153-bp with an opening reading frame (ORF) of 3132 nucleotides, which encoded a 1043-amino acid protein. The nucleotide sequences alignment showed that it had 98%, 97% and 87% homology with S. officinarum, Setaria italica and Lolium perenne, respectively. Moreover, the SsSPS was detected to express in leaf and stem tissues of S. spontaneum and exhibited a predominant expression in the stem tissue. However, there was no significant difference in the expression level of SsSPS between young leaves and mature ones. Additionally, we generated transgenic S. spontaneum using Agrobacterium-mediated transformation. Our data will provide a valuable foundation for further study of the potential role of SPS in plants.

Development of a set of multiplex PCRs for detection of genes encoding cell wall-associated proteins in Staphylococcus pseudintermedius isolates from dogs, humans and the environment

Staphylococcus pseudintermedius commonly colonizes the skin of dogs, whilst nasal carriage may occur in humans who are in contact with dogs or the environment of veterinary hospitals. Genes encoding cell wall-associated (CWA) proteins have been described in Staphylococcus aureus but knowledge of their occurrence in S. pseudintermedius is still limited. The aim of the study was to develop a method to detect S. pseudintermedius surface protein genes (sps) encoding CWA proteins, and to examine the distribution of the genes in isolates from different sources. Four multiplex PCR assays (mPCR) were developed for detection of 18 sps genes, with 4–5 genes detected per mPCR. These were applied to 135 S. pseudintermedius isolates from carriage sites (n=35) and infected sites (n=35) in dogs, from the nasal cavity of humans (n=25), and from the environment of a veterinary hospital (n=40). The mPCRs were shown to detect all 18 known sps genes, and no discrepancies were found between uniplex and mPCR results. The mPCRs could detect at least 1pg/μl of DNA template. A total of 23 sps gene profiles were found among the 135 isolates, with diverse gene combinations. Only spsD, spsF, spsI, spsO, spsP, and spsQ were not detected in all isolates. spsP and spsQ were more frequently detected in the canine isolates from infected sites than from carriage sites. This finding suggests that these two genes may play a role in pathogenicity, whereas the presence of the 12 sps genes may contribute to adherence function at all surfaces where carriage occurs.

Arabidopsis thaliana sucrose phosphate synthase (sps) genes are expressed differentially in organs and tissues, and their transcription is regulated by osmotic stress

Sucrose is synthesized from UDP-Glc and Fru-6-phosphate via the activity of sucrose-phosphate synthase (SPS) enzymes, which produce Suc-6-phosphate. Suc-6-phosphate is rapidly dephosphorylated by phosphatases to produce Suc and inorganic phosphate. Arabidopsis has four sps genes encoding SPS enzymes. Of these enzymes, AtSPS1F and AtSPS2F have been grouped with other dicotyledonous SPS enzymes, while AtSPS3F and AtSPS4F are included in groups with both dicotyledonous and monocotyledonous SPS enzymes. In this work, we generated Arabidopsis thaliana transformants containing the promoter region of each sps gene fused to gfp::uidA reporter genes. A detailed characterization of expression conferred by the sps promoters in organs and tissues was performed. We observed expression of AtSPS1F, AtSPS2F and AtSPS3F in the columella roots of the plants that support sucrose synthesis. Hence, these findings support the idea that sucrose synthesis occurs in the columella cells, and suggests that sucrose has a role in this tissue. In addition, the expression of AtSPS4F was identified in embryos and suggests its participation in this developmental stage. Quantitative transcriptional analysis of A. thaliana plants grown in media with different osmotic potential showed that AtSPS2F and AtSPS4F respond to osmotic stress.