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Here the sylvicultural and ecological analysis of typological structure of plantings silver and black poplar are presented for the riverine habitats of the Psel, Sula and Vorskla (the middle reaches of Seversky Donets river). Our analysis was based on forestry management electronic databases of Ukrainian National Forest Project Enterprise. More than 38 forest types on the area of 4.9 thousand hectares were examined. The biological features of silver and black poplar were described briefly. The silver and black poplar reproduction pattern of the Left-bank Forest-steppe of Ukraine was also examined. There was carried out the area allocation of tree species according the following points: forest type and origin, forest site quality, closure degree and age groups. By the tree stratum origin silver and black poplar are mostly artificially propagated, what is equivalent to 77.3 and 88.3 percent. The silver and black poplar area around the rivers' watershed of the Left-bank Forest-steppe of Ukraine occupies 2813 and 2173 ha consequently. Among forest types on research subject there are some forest types which dominate: fresh quercetum fluvialis (25.0 %), wet quercetum fluvialis (17.4 %), wet quercetum-birchbark-maple fluvialis (16.3 %), wet lime tree-oak-pine tree sudubrava (11.4 %), fresh lime tree, oak, pine tree sudubrava (5.2 %), the rest of tree types represents less than 4.0 % of the total land area, covered with sylva. The silver and black poplar plantings' distribution according to the site quality of forest on the rivers' columbine of the Left-bank Forest-steppe of Ukraine can be described in the following way: II and IV classes of the site quality of forest prevail, and the medium stocked tree stratum fluctuates from 52.9 to 87.8 per cent according to the normality. [ABSTRACT FROM AUTHOR]

This study was aimed to isolate, identify and characterize Pectobacterium spp. causing soft rot disease of cabbage and Chinese cabbage in Central Poland. Of fifty-two plant samples of cabbage and Chinese cabbage showing disease symptoms collected in Central Poland from 2007-2010, 542 bacterial isolates were obtained. Of isolates 117 caused soft rot on cabbage and Chinese cabbage leaves and potato slices and showed pectinolytic activity on crystal violet pectate medium. PCR using Y1/Y2 primers specific for Pectobacterium genus revealed that twenty-three of them belonged to this genus. Phenotypic characterization in combination with DNA-based typing methods (rep-PCRs) and sequence analysis of 16S rRNA, and housekeeping genes gyrB, infB, rpoB, atpD, and rpoS (MultiLocus Sequence Typing) done for 12 Polish representatives and reference strains allowed for their identification and revealed genetic diversity. Additional phylogeny analysis of the rpoS gene for Polish and worldwide well defined Pectobacterium spp. strains allowed to classify obtained strains into Pectobacterium spp. phylogenetic clusters (PcI-PcV). The presented studies showed that 8 of 12 isolated Pectobacterium carotovorum strains belong to the Pectobacterium carotovorum subsp. carotovorum (Pcc) cluster PcII and other four strains belong to the subspecies Pectobacterium carotovorum subsp. odoriferum (Pco) cluster PcIII. To our knowledge, this is the first report that P. carotovorum subsp. odoriferum causes soft rot of cabbage and Chinese cabbage in Central Poland. [ABSTRACT FROM AUTHOR]

Soft rot of Chinese cabbage is a disease of great economic importance to the State of Pernambuco, Brazil. The present study aimed to evaluate the effect of two calcium sources in different concentrations (calcium nitrate [Ca(NO)] at 0, 0.15 and 0.3 g l and calcium chloride (CaCl) at 0, 1 and 5 g l) that were applied through two methods (leaf spraying and soil drenching) on the control of soft rot. Further, it aimed to analyze calcium absorption by the plant and to determine calcium's role in leaf and cell structure using microscopy. Ca(NO) applied by both methods was effective in controlling soft rot caused by Pectobacterium carotovorum subsp. carotovorum, as it reduced the disease by up to 48.5 % when sprayed onto the leaves (0.15 g l). A significant increase in the leaf calcium content was observed only in the plants that were sprayed with higher doses of Ca(NO) and CaCl. In all of the calcium treatments, light microscopy analyses revealed an increased number of chloroplasts and improved structuring of the palisade parenchyma, while transmission electron microscopy analyses revealed an increased cell wall thickness that was especially evident for the 0.15 g l Ca(NO) treatment applied by leaf spraying and soil drenching. [ABSTRACT FROM AUTHOR]

The chemical composition in terms of flavonoid and salicylic compounds of leaves from 6 species and 3 hybrids of poplars (Populus) was identified with the use of TLC and HPLC-DAD/ESI-MS methods. Chromatographic analyses were carried out with 21 standard compounds including salicylic compounds (2), phenolic acids (3) and flavonoids (16). Moreover, on the basis of the obtained chromatographic data from the HPLC-DAD/ESI-MS and TLC separations, the presence of salicortin, tremulacin and chlorogenic acid was confirmed, depending on the analyzed poplar species or hybrid. The content of salicylic compounds was determined by HPLC-UV method and expressed on salicin as free and total fraction. Total flavonoid content was determined by spectroscopic method as quercetin equivalent. Significant qualitative and quantitative differences in the chemical composition of the analyzed leaves were demonstrated. The highest concentration of flavonoids (8.02 mg/g) was found in the leaves of Populus nigra, while the highest content of salicylic compounds (47.14 mg/g) was found in the leaves of P.×berolinensis. The antioxidant and xanthine oxidase inhibition properties of extracts from poplar leaves were investigated by TLC bioautography. It has been shown that the richest set of compounds with antioxidant properties are present in the leaves of P. alba, P.×candicans and P. nigra., (© 2021 Wiley-VHCA AG, Zurich, Switzerland.)

ABSTRACT In this study, by in situ reduction of Pd2+ ions attached on the surface of the sulfonated polystyrene (PS-SO3H) spheres, complete and dense palladium (Pd) nanoparticles (NPs) layer were deposited around PS-SO3H spheres. The PS@Pd spheres were wrapped by polypyrrole (PPy) shell, which could avoid escaping of Pd NPs. After selectively etching the PS core, the hollow structures with Pd NPs embedded in PPy capsule shell were obtained. The as-prepared Pd@PPy hollow capsules showed excellent catalytic activity toward the reduction of 4-nitroaniline because of the high Pd NPs loading. Furthermore, good reusabilty was demonstrated seven times without any detectible loss in activity. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43933. [ABSTRACT FROM AUTHOR]

Pectobacteria are one of the most important groups of plant pathogenic bacteria which occur world-wide. The bacteria have a wide host range and infect plants with fleshy organs. Thirty five bacterial isolates were collected from potato, cabbage, sugar beet, pepper, carrot, onion, cucumber, turnip, and tomato host plants cultivated in Fars province. The bacteria were identified using biochemical and physiological tests. The genetic diversity among the isolates was evaluated using RAPD assay. The isolates were rod-shape, gram-negative, facultative anaerobes, oxidase-negative, catalase-positive, and had ability to rot the potato, while they could not induce hypersensitive reaction on tobacco leaf. All of isolates were identified as soft-rot bacteria. Based on phenotypic criteria, the isolated strains were categorized into three groups. The strains of first, second and third groups were related to Pectobacterium carotovorum subsp. carotovorum, Pectobacterium betavascularum and Dickeya chrysanthemi, respectively. According to RAPD assay and using six primers including 19300, 91200, OPB07, OPB08, OPB11, OPB18, isolates categorized in three groups. The used primers showed significant diversity among the strains and the specific primers GTGC4, GAGC4 and GTG5 confirmed the classification. The diversity among the isolates has been confirmed based on the molecular works and clustering based on RAPD. This is the first RAPD assay to investigate the genetic diversity of soft-rot bacteria. [ABSTRACT FROM AUTHOR]

The rust fungi Melampsora larici-populina (Mlp) and Melampsora allii-populina (Map) are the main phytosanitary constraints for commercial poplar cultivation in Europe. Although Mlp is more aggressive and prevalent than Map, the two species may co-infect the same poplar tree or even the same poplar leaf, making the epidemiological surveys of each species difficult to achieve. In this study, a new duplex real-time PCR assay targeting each species was developed, based on single-copy genes. This test proved to be specific, inclusive and was successfully used to detect and quantify each species, starting from urediniospore samples or directly from infected poplar leaves, with or without visible symptoms. This new molecular tool was also assessed for comparative studies of time-course infection experiments on artificially inoculated poplar leaf discs. These studies showed that the growth dynamics of Map were significantly slower when the two species were co-inoculated on the same leaf disc, confirming that Map is less aggressive than Mlp. [ABSTRACT FROM AUTHOR]

Anthocyanins and volatile phenylpropenes (isoeugenol and eugenol) in petunia (Petunia hybrida) flowers have the precursor 4-coumaryl coenzyme A (CoA) in common. These phenolics are produced at different stages during flower development. Anthocyanins are synthesized during early stages of flower development and sequestered in vacuoles during the lifespan of the flowers. The production of isoeugenol and eugenol starts when flowers open and peaks after anthesis. To elucidate additional biochemical steps toward (iso)eugenol production, we cloned and characterized a caffeoyl-coenzyme A O-methyltransferase (PhCCoAOMT1) from the petals of the fragrant petunia 'Mitchell'. Recombinant PhCCoAOMT1 indeed catalyzed the methylation of caffeoyl-CoA to produce feruloyl CoA. Silencing of PhCCoAOMT1 resulted in a reduction of eugenol production but not of isoeugenol. Unexpectedly, the transgenic plants had purple-colored leaves and pink flowers, despite the fact that cv Mitchell lacks the functional R2R3-MYB master regulator ANTHOCYANIN2 and has normally white flowers. Our results indicate that down-regulation of PhCCoAOMT1 activated the anthocyanin pathway through the R2R3- MYBs PURPLE HAZE (PHZ) and DEEP PURPLE, with predominantly petunidin accumulating. Feeding cv Mitchell flowers with caffeic acid induced PHZ expression, suggesting that the metabolic perturbation of the phenylpropanoid pathway underlies the activation of the anthocyanin pathway. Our results demonstrate a role for PhCCoAOMT1 in phenylpropene production and reveal a link between PhCCoAOMT1 and anthocyanin production. [ABSTRACT FROM AUTHOR]

Background: The increased availability of genome sequences has advanced the development of genomic distance methods to describe bacterial diversity. Results of these fast-evolving methods are highly correlated with those of the historically standard DNA-DNA hybridization technique. However, these genomic-based methods can be done more rapidly and less expensively and are less prone to technical and human error. They are thus a technically accessible replacement for species delineation. Here, we use several genomic comparison methods, supported by our own proteomic analyses and metabolic characterization as well as previously published DNA-DNA hybridization analyses, to differentiate members of the Ralstonia solanacearum species complex into three species. This pathogen group consists of diverse and widespread strains that cause bacterial wilt disease on many different plants. Results: We used three different methods to compare the complete genomes of 29 strains from the R. solanacearum species complex. In parallel we profiled the proteomes of 73 strains using Matrix-Assisted Laser Desorption/Ionization-Time of Flight Mass Spectrometry (MALDI-TOF-MS). Proteomic profiles together with genomic sequence comparisons consistently and comprehensively described the diversity of the R. solanacearum species complex. In addition, genome-driven functional phenotypic assays excitingly supported an old hypothesis (Hayward et al. (J Appl Bacteriol 69:269-80, 1990)), that closely related members of the R. solanacearum could be identified through a simple assay of anaerobic nitrate metabolism. This assay allowed us to clearly and easily differentiate phylotype II and IV strains from phylotype I and III strains. Further, genomic dissection of the pathway distinguished between proposed subspecies within the current phylotype IV. The assay revealed large scale differences in energy production within the R. solanacearum species complex, indicating coarse evolutionary distance and further supporting a repartitioning of this group into separate species. Conclusions: Together, the results of these studies support the proposed division of the R. solanacearum species complex into three species, consistent with recent literature, and demonstrate the utility of proteomic and genomic approaches to delineate bacterial species. [ABSTRACT FROM AUTHOR]

Differences in Populus nigra L. clone resistance to the rust fungus Melampsora larici-populina Kleb. (MLP) were studied in field trials where infected trees were compared with fungicide-protected trees. MLP rust infections were assessed using a 6-point scale. Four parameters of poplar growth were also measured to gauge host response to infection: shoot thickness, shoot number at the end of the growing season, individual plant dry weight, and dry matter yield per unit area. Five of eight known pathogen virulence types were detected. Cumulative growth in shoot thickness in sprayed and unsprayed plots was similar in clones with high rust pathogen resistance, but significantly different in clones with low resistance. Clones with low resistance also exhibited delayed growth initiation in the year following infection, an effect attributed to lower food storage accumulated during the previous year, reflected in a reduction in stem diameter. Based on stem thickness measurements, it was confirmed growth ceased at the end of August. Average rust severity symptoms ranged from 2.75 to 4.22 on the 6-point scale. The percentage reduction for the various growth parameters resulting from rust infection ranged as follows: individual plant dry weight 5-64%; dry matter yield 21-66%; shoot number 17- 46%; and stem diameter 1-35%. Exclusive of stem diameter, these reductions correlated with severity in MLP rust infection. The one exception was tolerance to rust infection displayed by one of the clones. Clones with the lowest growth reductions were 97/152 and 97/157. Growth and yield parameter variation as a result MLP resistance difference was observed among tested P. nigra clones. This variation can be viewed as confirmation that resistance observed in this study and P. nigra clones is a suite of quantitative traits. These findings have important implications for MLP resistance breeding programs. [ABSTRACT FROM AUTHOR]

Rapid and accurate genome-wide marker detection is essential to the marker-assisted breeding and functional genomics studies. In this work, we developed an integrated software, AgroMarker Finder (AMF: ), for providing graphical user interface (GUI) to facilitate the recently developed restriction-site associated DNA (RAD) sequencing data analysis in rice. By application of AMF, a total of 90,743 high-quality markers (82,878 SNPs and 7,865 InDels) were detected between rice varieties JP69 and Jiaoyuan5A. The density of the identified markers is 0.2 per Kb for SNP markers, and 0.02 per Kb for InDel markers. Sequencing validation revealed that the accuracy of genome-wide marker detection by AMF is 93%. In addition, a validated subset of 82 SNPs and 31 InDels were found to be closely linked to 117 important agronomic trait genes, providing a basis for subsequent marker-assisted selection (MAS) and variety identification. Furthermore, we selected 12 markers from 31 validated InDel markers to identify seed authenticity of variety Jiaoyuanyou69, and we also identified 10 markers closely linked to the fragrant gene BADH2 to minimize linkage drag for Wuxiang075 (BADH2 donor)/Jiachang1 recombinants selection. Therefore, this software provides an efficient approach for marker identification from RAD-seq data, and it would be a valuable tool for plant MAS and variety protection. [ABSTRACT FROM AUTHOR]

To identify bacteria causing severe soft rot on potato in Lebanon, pectinolytic bacteria were isolated from diseased samples collected in the Bekaa valley and the Akkar region, during 2009-2010. Six isolates that induced a hypersensitive reaction in tobacco plants and caused a marked soft rot when inoculated in potato tubers or stem, DAPP-PG 752 to DAPP-PG 757, were further characterized. Analysis of 16S-23S intergenic transcribed spacer-regions, digested with RsaI and CfoI, demonstrated that isolates DAPP-PG 753 to DAPP-PG 757 showed electrophoretic profiles similar to that of LMG 2408, a strain misclassified as Pectobacterium carotovorum subsp. carotovorum, and different from that of DAPP-PG 752. Phylogenetic analysis using partial malate dehydrogenase gene sequences, clustered DAPP-PG 752 in a clade that contained the type strain of P. carotovorum subsp. carotovorum, while DAPP-PG 753 to DAPP-PG 757, together with LMG 2408, fell in a clade including strains of the recently described species Pectobacterium aroidearum. Multilocus sequence analysis of concatenated partial sequences of the atpD, gyrB, infB and rpoB genes confirmed the results obtained with the mdh gene sequences and identified DAPP-PG 752 as P. carotovorum, and LMG 2408 and the five related Lebanese isolates as P. aroidearum. The Lebanese P. aroidearum isolates were phenotypically similar to known P. aroidearum strains, based on API 50 CHE data. They showed identical BOX- and ERIC-PCR profiles that resembled profiles of known P. aroidearum strains. This study represents the first official report of P. aroidearum as causal agent of soft rot on potato plants and the first occurrence of P. carotovorum subsp. carotovorum on potato plants in Lebanon. [ABSTRACT FROM AUTHOR]

In the near future, grasses must provide most of the biomass for the production of renewable fuels. However, grass cell walls are characterized by a large quantity of hydroxycinnamic acids such as ferulic and p-coumaric acids, which are thought to reduce the biomass saccharification. Ferulic acid (FA) binds to lignin, polysaccharides and structural proteins of grass cell walls cross-linking these components. A controlled reduction of FA level or of FA cross-linkages in plants of industrial interest can improve the production of cellulosic ethanol. Here, we review the biosynthesis and roles of FA in cell wall architecture and in grass biomass recalcitrance to enzyme hydrolysis. [ABSTRACT FROM AUTHOR]

AFLP or amplified fragment length polymorphism is a PCR-based molecular technique that uses selective amplification of a subset of digested DNA fragments from any source to generate and compare unique fingerprints of genomes. It is more efficient in terms of time, economy, reproducibility, informativeness, resolution, and sensitivity, compared to other popular DNA markers. Besides, it requires very small quantities of DNA and no prior genome information. This technique is widely used in plants for taxonomy, genetic diversity, phylogenetic analysis, construction of high-resolution genetic maps, and positional cloning of genes, to determine relatedness among cultivars and varietal identity, etc. The review encompasses in detail the various applications of AFLP in plants and the major advantages and disadvantages. The review also considers various modifications of this technique and novel developments in detection of polymorphism. A wet-lab protocol is also provided.

The aim of this study was to evaluate the environmental fate and behaviour of the biocontrol product based on Pantoea agglomerans CPA-2 cells after its release into the field. Three different methods, dilution plating, quantitative real-time PCR ( qPCR) and propidium monoazide combined with qPCR ( PMA-qPCR) were used to track the CPA-2 population. Populations quantified by qPCR were statistically different compared with those by the PMA-qPCR and dilution plating methods. In addition, the spray dispersion of the CPA-2 treatment was evaluated using water-sensitive papers. A lack of dispersion of the CPA-2 treatment was observed at distances of 2.5 ± 0.5 m. The presence and persistence of CPA-2 in the environment were monitored in different areas, by dilution plating and confirmed by conventional PCR. The results showed that CPA-2 can survive but not proliferate on weed and leaves. The persistence on inert surfaces, such as motorised backpack sprayer, gloves and working clothes, was less than 7 days. In conclusion, PMA-qPCR was a potential tool for fast and specific monitoring of viable populations of CPA-2 and it gave valuable information on population behaviour. Moreover, the results demonstrate that CPA-2 would not present a risk for the environment because of its low establishment, survival and dispersion. [ABSTRACT FROM AUTHOR]

The aim of this study was characterized Pectobacterium carotovorum subsp. carotovorum (Pcc) the causal pathogen of watermelon soft rot disease in Iran. Of fifty bacterial isolates with white grey and convex colonies on nutrient agar obtained from symptomatic watermelon, ten isolates were selected for further tests. Pathogenicity tests results showed that all test isolates developed typical water-soak symptoms after 2 days and signs of soft rot began 4 days after inoculation on watermelon fruits. Based on the phenotypic properties, the isolates were identified as Pectobacterium carotovorum subsp. carotovorum. The 16S rDNA sequences of isolates were 99% similar to the corresponding 16S rDNA sequence of the reference Pcc isolate. BOX and ERIC- PCR analysis indicated that genetic diversity was present among the isolated Pcc isolates did not relate to the geographic location isolated from. To the best of our knowledge, this is the first study of biochemical and genotypic characterization of Pcc isolates the causal agents of soft rot disease on watermelon, in Iran. [ABSTRACT FROM AUTHOR]

A novel strain of Pectobacterium, isolated from infected sunflower plants ( Helianthus annuus L.) in Mexico was characterized. Inoculated sunflower plants developed both tissue chlorosis and soft-rot on leaves. The broad host range shown by this pathogen, which included members of the Agavaceae, Asteraceae, Brassicaceae and Solanaceae, was characteristic of the genus Pectobacterium. The metabolic profile and molecular data, in addition to the secretion of plant-cell-wall-degrading enzymes, confirmed its identification as a member of the Pectobacterium genus. A phylogenetic tree constructed on the basis of its 16S rDNA sequence revealed a high identity (98 %) with P. cacticidum. Amplification and restriction-fragment-length-polymorphism analysis of internal transcribed sequences further confirmed its classification as P. cacticidum. Similar to strains of P. atrosepticum, P. carotovorum and Dickeya spp., the new P. cacticidum strain FHLGJ22 has a coronafacic ligase gene and produces coronatine, a virulence factor usually associated with phytopathogenic strains of Pseudomonas syringae. Our results suggest that this strain may utilize a dual infection process involving cell maceration and plant toxins, which is synchronized via an unknown mechanism, might confer an adaptive advantage to colonize different plant hosts. [ABSTRACT FROM AUTHOR]

Altering gene dosage through variation in gene copy number is a powerful approach to addressing questions regarding gene regulation, quantitative trait loci, and heterosis, but one that is not easily applied to sexually transmitted species. Elite poplar (Populus spp) varieties are created through interspecific hybridization, followed by clonal propagation. Altered gene dosage relationships are believed to contribute to hybrid performance. Clonal propagation allows for replication and maintenance of meiotically unstable ploidy or structural variants and provides an alternative approach to investigating gene dosage effects not possible in sexually propagated species. Here, we built a genome-wide structural variation system for dosage-based functional genomics and breeding of poplar. We pollinated Populus deltoides with gamma-irradiated Populus nigra pollen to produce >500 F1 seedlings containing dosage lesions in the form of deletions and insertions of chromosomal segments (indel mutations). Using high-precision dosage analysis, we detected indel mutations in ∼55% of the progeny. These indels varied in length, position, and number per individual, cumulatively tiling >99% of the genome, with an average of 10 indels per gene. Combined with future phenotype and transcriptome data, this population will provide an excellent resource for creating and characterizing dosage-based variation in poplar, including the contribution of dosage to quantitative traits and heterosis. [ABSTRACT FROM AUTHOR]

Xylem resistance to drought-induced cavitation is a key trait of plant water relations. This study assesses the genetic variation expressed for stem cavitation resistance within a population of a riparian species, the European black poplar (Populus nigra L.), and explores its relationships with xylem anatomy, water-use efficiency (WUE), and growth. Sixteen structural and physiological traits related to cavitation resistance, xylem anatomy, growth, bud phenology, and WUE were measured on 33 P. nigra genotypes grown under optimal irrigation in a 2-year-old clonal experiment in a nursery. Significant genetic variation was expressed for the xylem tension inducing 50% loss of hydraulic conductivity (Ψ50) within the studied population, as attested by the high value of broad-sense heritability estimated for this trait (H²ind = 0.72). Stem cavitation resistance was associated with xylem structure: the more cavitation-resistant genotypes exhibited lower hydraulic efficiency and higher mechanical reinforcement as assessed from stem xylem cross sections. By contrast, Ψ50 was not significantly related to shoot height increment, total above-ground dry mass, or bulk leaf carbon isotope discrimination, a proxy for intrinsic WUE. These findings indicate that the trade-offs between xylem resistance to cavitation, hydraulic efficiency, and mechanical reinforcement can occur at the within-population level. Given that the studied genotypes were exposed to the same environmental conditions and evolutionary drivers in situ, the trade-offs detected at this scale are expected to reflect true functional relationships. [ABSTRACT FROM AUTHOR]

Main conclusion: TaCCoAOMT1 is located in wheat chromosome 7A and highly expressed in stem and root. It is important for lignin biosynthesis, and associated with stem maturity but not lodging resistance. Caffeoyl coenzyme A 3- O-methyltransferases (CCoAOMTs) are one important class of enzymes to carry out the transfer of the methyl group from S-adenosylmethionine to the hydroxyl group, and play important roles in lignin and flavonoids biosynthesis. In the present study, sequences for CCoAOMT from the wheat genome were analyzed. One wheat CCoAOMT that belonged to bona fide subclade involved in lignin biosynthesis, namely TaCCoAOMT1, was obtained by the prokaryotic expression in E. coli. The three-dimensional structure prediction showed a highly similar structure of TaCCoAOMT1 with MsCCoAOMT. Recombinant TaCCoAOMT1 protein could only use caffeoyl CoA and 5-hydroxyferuloyl CoA as effective substrates and caffeoyl CoA as the best substrate. TaCCoAOMT1 had a narrow optimal pH and thermal stability. The TaCCoAOMT1 gene was highly expressed in wheat stem and root tissues, paralleled CCoAOMT enzyme activity. TaCCoAOMT1 mRNA abundance and enzyme activity increased linearly with stem maturity, but showed little difference between wheat lodging-resistant (H4546) and lodging-sensitive (C6001) cultivars in elongation, heading and milky stages. These data suggest that TaCCoAOMT1 is an important CCoAOMT for lignin biosynthesis that is critical for stem development, but not directly associated with lodging-resistant trait in wheat. [ABSTRACT FROM AUTHOR]

Vulnerability to drought-induced cavitation is a key trait of plant water relations. Here, we summarize the available literature on vulnerability to drought-induced cavitation in poplars ( P opulus spp.), a genus of agronomic, ecological and scientific importance. Vulnerability curves and vulnerability parameters (including the water potential inducing 50% loss in hydraulic conductivity, P50) were collected from 37 studies published between 1991 and 2014, covering a range of 10 species and 12 interspecific hybrid crosses. Results of our meta-analysis confirm that poplars are among the most vulnerable woody species to drought-induced cavitation (mean P50 = −1.44 and −1.55 MPa across pure species and hybrids, respectively). Yet, significant variation occurs among species ( P50 range: 1.43 MPa) and among hybrid crosses ( P50 range: 1.12 MPa), within species and hybrid crosses (max. P50 range reported: 0.8 MPa) as well as in response to environmental factors including nitrogen fertilization, irradiance, temperature and drought (max. P50 range reported: 0.75 MPa). Potential implications and gaps in knowledge are discussed in the context of poplar cultivation, species adaptation and climate modifications. We suggest that poplars represent a valuable model for studies on drought-induced cavitation, especially to elucidate the genetic and molecular basis of cavitation resistance in Angiosperms. [ABSTRACT FROM AUTHOR]

In this review, we describe the latest advances in synthesis, characterization, and applications of polymer brushes. Synthetic advances towards well-defined polymer brushes, which meet criteria such as: (i) Efficient and fast grafting, (ii) Applicability on a wide range of substrates; and (iii) Precise control of surface initiator concentration and hence, chain density are discussed. On the characterization end advances in methods for the determination of relevant physical parameters such as surface initiator concentration and grafting density are discussed. The impact of these advances specifically in emerging fields of nano- and bio-technology where interfacial properties such as surface energies are controlled to create nanopatterned polymer brushes and their implications in mediating with biological systems is discussed. [ABSTRACT FROM AUTHOR]

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A facile and efficient strategy for the preparation of polymer grafts on zirconia particles is developed by means of self-initiated photografting and photopolymerization. The UV-induced grafting polymerization is applicable to a variety of polymerizable monomers, allowing the direct formation of homogeneous and stable polymer coatings on zirconia particles without any initiator immobilization. The as-prepared polymer grafts are proved to be efficient supports for polyoxometalates as H3PW12O40 can be uniformly and stably immobilized on a poly(4-vinylpyridine) layer through electrostatic interaction. The resulting hybrid catalyst system, associated with high catalytic activity for a series of oxidation reactions such as amines, alkenes, alcohols and sulfides, represents a novel and efficient system with a high catalyst loading capacity and stability upon reuse in further cycles. © 2014 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Lignin is an aromatic polymer derived from the combinatorial coupling of monolignol radicals in the cell wall. Recently, various glycosylated lignin oligomers have been revealed in Arabidopsis thaliana. Given that monolignol oxidation and monolignol radical coupling are known to occur in the apoplast, and glycosylation in the cytoplasm, it raises questions about the subcellular localization of glycosylated lignin oligomer biosynthesis and their storage. By metabolite profiling of Arabidopsis leaf vacuoles, we show that the leaf vacuole stores a large number of these small glycosylated lignin oligomers. Their structural variety and the incorporation of alternative monomers, as observed in Arabidopsis mutants with altered monolignol biosynthesis, indicate that they are all formed by combinatorial radical coupling. In contrast to the common believe that combinatorial coupling is restricted to the apoplast, we hypothesized that the aglycones of these compounds are made within the cell. To investigate this, leaf protoplast cultures were cofed with 13C6-labeled coniferyl alcohol and a 13C4-labeled dimer of coniferyl alcohol. Metabolite profiling of the cofed protoplasts provided strong support for the occurrence of intracellular monolignol coupling. We therefore propose a metabolic pathway involving intracellular combinatorial coupling of monolignol radicals, followed by oligomer glycosylation and vacuolar import, which shares characteristics with both lignin and lignan biosynthesis. [ABSTRACT FROM AUTHOR]

A large-scale metabolic quantitative trait loci (mQTL) analysis was performed on the well-characterized Solanum pennellii introgression lines to investigate the genomic regions associated with secondary metabolism in tomato fruit pericarp. In total, 679 mQTLs were detected across the 76 introgression lines. Heritability analyses revealed that mQTLs of secondary metabolism were less affected by environment than mQTLs of primary metabolism. Network analysis allowed us to assess the interconnectivity of primary and secondary metabolism as well as to compare and contrast their respective associations with morphological traits. Additionally, we applied a recently established real-time quantitative PCR platform to gain insight into transcriptional control mechanisms of a subset of the mQTLs , including those for hydroxycinnamates, acyl-sugar, naringenin chalcone, and a range of glycoalkaloids. Intriguingly, many of these compounds displayed a dominant-negative mode of inheritance, which is contrary to the conventional wisdom that secondary metabolite contents decreased on domestication. We additionally performed an exemplary evaluation of two candidate genes for glycolalkaloid mQTLs via the use of virus-induced gene silencing. The combined data of this study were compared with previous results on primary metabolism obtained from the same material and to other studies of natural variance of secondary metabolism. [ABSTRACT FROM AUTHOR]

Bacterial soft rot is a new disease that, in recent years, has caused significant economic losses to banana production in China. Four bacterial isolates representative of a larger group of bacteria recovered from diseased banana plants located in different regions of China and a strain of Dickeya zeae (Ec1) from rice, used as control, were characterized by morphological, physiological, biochemical, and molecular assays. Results showed that the bacterial isolates from banana were Gram-negative, rod-shaped with multiple flagella, and produced a brown pigment on NGM medium (nutrient agar supplemented with 1% glycerol), indicating that they belong to Dickeya. Physiological and biochemical assays revealed that all bacteria from banana were in fact isolates of D. zeae differing from Dickeya dieffenbachiae and Dickeya paradisiaca. Phylogenetic analysis in comparison with sequences of 14 strains of Dickeya spp. retrieved from GenBank was done using the concatenated partial sequences of the seven housekeeping genes dnaA, dnaJ, dnaX, gyrB, recN, gapA, and mdh. All banana isolates were closely related to D. zeae and distinct from other Dickeya spp. The germination rate of rice seeds soaked with bacterial culture supernatant (crude toxin) and toxin bacteriostatic test results showed that the banana strains were different from D. zeae Ec1 in toxin production. [ABSTRACT FROM AUTHOR]

The uredinial stage in the life cycle of Melampsora larici- populina on poplar leaves is the most important pathogenic phase. We captured partial phases of uredinial infection in the wild, aiming to reconstruct the process of uredinial ontogeny by using scanning and transmission electron microscope. At the initial infection stage, germ tubes germinated from the echinulate urediniospores. Germ tubes were frequently seen to merge with the leaf surface and cuticle breakage was observed, indicating direct hyphal penetration. Stomata penetration occurred commonly, sometimes with more than one germ tube penetrating the same stoma. Melampsora larici- populina did not form appressoria in the infection process, implying that infectious behavior of this pathogen may differ from the other rust pathogens. In general, germ tubes branched randomly, and no distinct evidence indicated that stoma could induce or orient germ tube branches. However, oriented germ tube growth has been occasionally observed in other studies. The urediniospores collapsed and finally wizened when they became nutrient stressed. At the last stage of infection, the uredinia erupted from the leaf epidermis and appeared as orange pustules on the leaf surface. [ABSTRACT FROM AUTHOR]

Context: It might be possible to establish a new generation of Fraxinus excelsior which is insusceptible towards ash dieback (agent: Hymenoscyphus pseudoalbidus) by efficient breeding. However, a considerable number of highly tolerant individuals which have the ability to pass on this trait to their progeny are needed. Aims: The aim of this study was to identify the potential of provenances from southwestern Germany as a source of future selection for resistance or resistance breeding. Methods: In July 2012 and 2013, ash dieback severity was scored by assessing the crown defoliation and the portion of epicormic shoots in the crowns in clonal seed orchards with a total of 1,726 ash trees in southwestern Germany. Results: Ash dieback severity differed strongly between the orchards and the clones. Broad-sense heritability ranged from 0.18 to 0.55 for crown defoliation and from 0.48 to 0.58 for the portion of epicormic shoots between the orchards. Clones from nearby populations did not show differences in general levels of susceptibility. Conclusion: The study highlights that there is high genetic variation in susceptibility and considerable genetic potential for resistance breeding in provenances from southwestern Germany. [ABSTRACT FROM AUTHOR]

Presymptomatic and accurate diagnoses of pathogens are essential for disease prediction and the timely application of bactericide. The bacterium Lonsdalea quercina (=Brenneria quercina) has been reported as the causal agent of drippy nut and bark canker disease on oak in California (US) and Europe. In recent years, it is also found on Populus × euramericana trees in Henan province of China. This bacterium causes longitudinal cankers of a few centimetres in size on the bark surface of the upper trunk. In this study, we developed two speciesspecific PCR assays using primer pairs LqfF/LqfR and LqgF/LqgR for the rapid and accurate detection of the pathogenic bacteria in diseased plant tissues. The results show that the LqfF/LqfR primers amplified only a single PCR band of approximately 382 bp and the LqgF/ LqgR primers yielded a PCR product of approximately 286 bp. The two primers were successfully adapted to real-time PCR based on SYBR Green I used with the ABI 7500 system. The detection limit of the reaction was 0.1 pg genomic DNA per 20 μl PCR reaction volumes. The pathogen was mainly detected in the phloem of cankers as well as in the exudates of diseased trees, but was not found in the xylem or leaves. The size of pathogen in distribution was larger than the lesion. The results demonstrate that real-time PCR assays can be used to detect the pathogen by extracting DNA directly from infected plant tissues. This method is a rapid, reliable method for the presymptomatic and accurate detection of L. quercina, providing a useful insight into epidemiological studies. [ABSTRACT FROM AUTHOR]

The soft rot Enterobacteriaceae ( SRE) Pectobacterium and Dickeya species (formerly classified as pectinolytic Erwinia spp.) cause important diseases on potato and other arable and horticultural crops. They may affect the growing potato plant causing blackleg and are responsible for tuber soft rot in storage thereby reducing yield and quality. Efficient and cost-effective detection and identification methods are essential to investigate the ecology and pathogenesis of the SRE as well as in seed certification programmes. The aim of this review was to collect all existing information on methods available for SRE detection. The review reports on the sampling and preparation of plant material for testing and on over thirty methods to detect, identify and differentiate the soft rot and blackleg causing bacteria to species and subspecies level. These include methods based on biochemical characters, serology, molecular techniques which rely on DNA sequence amplification as well as several less-investigated ones. [ABSTRACT FROM AUTHOR]

The plant GT43 protein family includes xylosyltransferases that are known to be required for xylan backbone biosynthesis, but have incompletely understood specificities. RT-q PCR and histochemical ( GUS) analyses of expression patterns of GT43 members in hybrid aspen, reported here, revealed that three clades of the family have markedly differing specificity towards secondary wall-forming cells (wood and extraxylary fibres). Intriguingly, GT43 A and B genes (corresponding to the Arabidopsis IRX9 clade) showed higher specificity for secondary-walled cells than GT43 C and D genes ( IRX14 clade), although both IRX9 and IRX14 are required for xylosyltransferase activity. The remaining genes, GT43 E, F and G ( IRX9- L clade), showed broad expression patterns. Transient transactivation analyses of GT43 A and B reporters demonstrated that they are activated by Ptxt MYB021 and PNAC085 (master secondary wall switches), mediated in Ptxt MYB021 activation by an AC element. The high observed secondary cell wall specificity of GT43 B expression prompted tests of the efficiency of its promoter ( p GT43 B), relative to the Ca MV 35 S ( 35 S) promoter, for overexpressing a xylan acetyl esterase ( CE5) or downregulating REDUCED WALL ACETYLATION ( RWA) family genes and thus engineering wood acetylation. CE5 expression was weaker when driven by p GT43 B, but it reduced wood acetyl content substantially more efficiently than the 35 S promoter. RNAi silencing of the RWA family, which was ineffective using 35 S, was achieved when using GT43 B promoter. These results show the utility of the GT43 B promoter for genetically engineering properties of wood and fibres. [ABSTRACT FROM AUTHOR]

Two high-resolution strain discrimination methods based on variable number tandem repeat (VNTR) analysis were devised for the plant soft-rotting pathogens Dickeya dianthicola and Dickeya solani and used to investigate their diversity and epidemiology. Analysis of D. dianthicola identified 19 VNTR profiles (P1-P19). Diversity was observed in the earliest strains analysed (from 1957), which included four profiles from European strains isolated from Dianthus caryophyllus (P4, P7, P8 and P11) and one from Chrysanthemum morifolium (also P7) originating from the USA. Eleven D. dianthicola VNTR profiles were identified from potato dating from 1984. The time period between which specific D. dianthicola VNTR profiles were first isolated from ornamental hosts and then from potato, was between 8 and 16 years respectively. Identification of two profiles (P2 and P8) that occurred in both ornamental hosts and potato supported cross-infection between these hosts. Limited variation in VNTR profile was identified from strains of D. solani, from which only three VNTR profiles were discriminated by variation at only one of five loci, which may reflect the short time period and/or limited number of D. solani introductions since the pathogen's first emergence in Europe. Shared profiles between D. solani isolates from hyacinth and potato strains, is consistent with cross infection between hosts grown for horticultural production and potato. [ABSTRACT FROM AUTHOR]

Both natural and managed forests are currently suffering from increases in damage by pathogens. Here, an evolutionary ecology approach is adopted to analyse the factors that influence the levels of pathogen damage experienced by forest tree populations and consider the conditions under which stable co-existence of trees and pathogens occurs in natural populations. The demographic and genetic responses of tree–pathogen systems to anthropogenic perturbations are explored to identify where the greatest threats to resilience lie. Problems caused by native pathogens are likely to arise as a consequence both of rapid climate change and of forest management practices that lead to increases in species density, drastic reductions in genetic diversity and planting outside the native range. The most serious threats to forest trees are posed by introduction of exotic pathogens derived from related exotic tree species. Recovery following spread of exotic pathogens is likely to be both slow and uncertain and may not be possible without intensive programmes involving rapid selection and widespread dissemination of genotypes resistant to the exotic pathogen. [ABSTRACT FROM AUTHOR]

Sapwood, heartwood and bark of 70-year-old teak trees from an unmanaged stand in East Timor were characterized by pyrolysis (Py-GC-MS/FID). Sapwood and heartwood from teak presented a high lignin content (35.4 and 37.3 % of extractive-free wood) and similar composition. Teak wood is characterized by a GS type of lignin (56.0 % of G-units, 42.2 % of S-units and 1.8 % of H-units in extractive-free wood), with an S/G ratio of 0.8. The major lignin-derived compounds were 4-vinylsyringol (6.6 %), coniferyl alcohol ( trans) (4.5 %), coniferaldehyde (2.0 %), 4-vinylguaiacol (1.6 %) and 4-methylguaiacol (1.6 %). Extractive-free teak bark presented 28.0 % of lignin, characterized by a GS type, with 53.3 % G-units, 42.1 % S-units and 4.6 % H-units, with S/G ratio of 0.8. The high lignin content and a composition with predominance of G-units may contribute to the durability and mechanical resistance of teakwood. [ABSTRACT FROM AUTHOR]

In order to examine the potential for coproduct generation, we have characterised chemical compounds released by a range of alkaline and acidic aqueous pretreatments as well as the effect of these pretreatments on the saccharification ability of the lignocellulosic material. Comparative experiments were performed using three biomass types chosen for their potential as second-generation biofuel feedstocks: maize stover, miscanthus and sugarcane bagasse. The release of lignin from the feedstock correlated with the residual biomass saccharification potential, which was consistently higher after alkaline pretreament for all three feedstock types. Alkaline pretreatment released more complex mixtures of pentose and hexose sugars into the pretreatment liquor than did acid pretreatment. In addition, complex mixtures of aromatic and aliphatic compounds were released into pretreatment liquors under alkaline conditions, in a temperature-dependent manner, but far less so under acidic conditions. We show that the three feedstocks characterised interact with the pretreatment conditions in a specific manner to generate different ranges of products, highlighting the need to tailor pretreatments to both the starting feedstock and desired outcomes. [ABSTRACT FROM AUTHOR]

The European Commission requested the EFSA Panel on Plant Health to perform the pest categorisation for Erwinia amylovora, which is the causal agent of fire blight. E. amylovora is a plant pathogenic bacterium regulated by the Directive 2000/29/EC (Annexes II-A-II). E. amylovora is a single taxonomic entity. This organism can be accurately identified, based on a range of discriminative methods. Detection methods are available for symptomatic and asymptomatic plant material. E. amylovora ispresent in all EU Member States except Estonia, Finland and Malta, where host plants are not widely distributed or are rare. The host plants (mainly pear and apple) are cultivated throughout Europe where environmental conditions are conducive to disease development. Although no recent data are available on losses caused by E. amylovora in the EU, fire blight is considered to be the most destructive disease on pear and apple owing to the loss of trees. The analysis of past disease outbreaks previously reported in the EU highlights their considerable potential to have a severe impact on commercial horticulture, especially on apple, pear and quince, as well as on ornamentals and on nursery trade. The disease causes a range of symptoms on the aerial parts of plants, including the fruits, and E. amylovora often kills the trees and causes destructive outbreaks. Contaminated rootstocks, cuttings and grafted trees for transplanting, beehive transportation, rain and wind, are responsible for medium- and long-distance dissemination of the pathogen. Existing control is mainly based on prevention and exclusion. The use of chemical or biological products can prevent infection, and sanitation methods applied to infected plants can control the disease to a certain extent. No curative chemical control agents are available that eradicate E. amylovora in infected orchards. [ABSTRACT FROM AUTHOR]

In order to efficiently grow Salix for biomass production in warmer climates, varieties with a desirable response to drought and nutrient-limiting conditions are needed. The main objective of this study was to investigate the genetic background of biomass production and nitrogen (N) economy in contrasting conditions of water and nutrient availability and to identify candidate genes with a putative function in the expression of the different traits. Quantitative trait loci (QTLs) analysis was conducted using data from 198 individuals of a back-cross population between S. viminalis and S. schwerinii grown in a greenhouse under three combinations of N and water supply. In total, 60 QTLs were identified for biomass and N economy traits in the different treatments. Most of the QTLs mapped to linkage groups II, III, VI, X, XIII and B. At linkage groups III, VI and X, QTLs for both N economy and biomass traits co-located. The phenotypic variation explained by each QTL varied from 7.7 to 41.9 % of the total variance. QTLs for N economy traits explained most of the variation. Gene ontology (GO) analyses, performed on QTL intervals for each trait and projected to the Populus trichocarpa genome, revealed that genomic intervals connected to 19 traits were enriched for at least one GO term. Candidate genes were selected among genes linked to the enriched GO terms. These results represent a first necessary step for additional mapping and functional studies and encourage the development of marker-assisted breeding of Salix varieties adapted to drier climates. [ABSTRACT FROM AUTHOR]

A multiplex polymerase chain reaction (PCR) assay for simultaneous, fast and reliable detection of the main soft rot and blackleg potato pathogens in Europe has been developed. It utilises three pairs of primers and enables detection of three groups of pectinolytic bacteria frequently found in potato, namely: Pectobacterium atrosepticum, Pectobacterium carotovorum subsp. carotovorum together with Pectobacterium wasabiae and Dickeya spp. in a multiplex PCR assay. In studies with axenic cultures of bacteria, the multiplex assay was specific as it gave positive results only with strains of the target species and negative results with 18 non-target species of bacteria that can possibly coexist with pectinolytic bacteria in a potato ecosystem. The developed assay could detect as little as 0.01 ng µL-1 of Dickeya sp. genomic DNA, and down to 0.1 ng µL-1 of P. atrosepticum and P. carotovorum subsp. carotovorum genomic DNA in vitro. In the presence of competitor genomic DNA, isolated from Pseudomonas fluorescens cells, the sensitivity of the multiplex PCR decreased tenfold for P. atrosepticum and Dickeya sp., while no change was observed for P. carotovorum subsp. carotovorum and P. wasabiae. In spiked potato haulm and tuber samples, the threshold level for target bacteria was 101 cfu mL-1 plant extract (102 cfu g-1 plant tissue), 102 cfu mL-1 plant extract (103 cfu g-1 plant tissue), 103 cfu mL-1 plant extract (104 cfu g-1 plant tissue), for Dickeya spp., P. atrosepticum and P. carotovorum subsp. carotovorum/ P. wasabiae, respectively. Most of all, this assay allowed reliable detection and identification of soft rot and blackleg pathogens in naturally infected symptomatic and asymptomatic potato stem and progeny tuber samples collected from potato fields all over Poland. [ABSTRACT FROM AUTHOR]

The induction of plant immunity by Pathogen Associated Molecular Patterns (PAMPs) constitutes a powerful strategy for crop protection. PAMPs indeed induce general defense responses in plants and thus increase plant resistance to pathogens. Phytophthora infestans culture filtrates (CCFs) are known to induce defense responses and decrease the severity of soft rot due to Pectobacterium atrosepticum in potato tubers. The aim of this study was to identify and characterize the active compounds from P. infestans filtrate. The filtrate was fractionated by gel filtration, and the protection effects against P. atrosepticum and the ability to induce PAL activity were tested for each fraction. The fraction active in protection (F1) also induced PAL activity, as did the whole filtrate. Three elicitins (INF1, INF4 and INF5) were identified in F1b, subfraction of F1, by MALDI-TOF-MS and MS/MS analyses. However, deproteinized F1b still showed biological activity against the bacterium, revealing the presence of an additional active compound. GC-MS analyses of the deproteinized fraction highlighted the presence of a galactan-based complex polysaccharide. These experiments demonstrate that the biological activity of the CCF against P. atrosepticum results from a combined action of three elicitins and a complex polysaccharide, probably through the activation of general defense responses. [ABSTRACT FROM AUTHOR]

Lonsdalea quercina N-5-1 is a bacterial pathogen that causes poplar bark cankers. It has been isolated from the branch of Populus × euramericana cv. '74/76' in Henan, China. Previous studies have revealed that the Type III secretion system (T3SS) acts as an essential pathogenic factor in L. quercina N-5-1. HrpW is a putative effector of T3SS in strain N-5-1, which has a typical harpin domain at the amino terminal and a pectate lyase (Pel) domain at its carboxyl terminal. Genetic evidence had shown that, compared to the wild-type and the complementary strain, the hrpW mutation causes a small but significant reduction in virulence when inoculated on the poplar branches. The amino terminal domain of HrpW was found to trigger tobacco hypersensitive response, but the carboxyl terminal domain of HrpW was not. Unlike most HrpW homologs in other bacteria, the carboxyl terminal domain of HrpW of strain N-5-1 exhibited detectable pectate lyase activity. Site-direction mutations (W104A, W171M) further demonstrated that two tryptophan residues were essential to its pectate lyase activity. The results of the present work suggest that HrpW in L. quercina N-5-1 possesses pectate lyase activity and acts as a nonessential but important pathogenic factor in poplar bark canker disease. [ABSTRACT FROM AUTHOR]

In laboratory experiments, the antifouling (AF) properties of zinc oxide (ZnO) nanorod coatings were investigated using the marine bacteriumAcinetobactersp. AZ4C, larvae of the bryozoanBugula neritinaand the microalgaTetraselmissp. ZnO nanorod coatings were fabricated on microscope glass substrata by a simple hydrothermal technique using two different molar concentrations (5 and 10?mM) of zinc precursors. These coatings were tested for 5?h under artificial sunlight (1060?W?m?2or 530?W?m?2) and in the dark (no irradiation). In the presence of light, both the ZnO nanorod coatings significantly reduced the density ofAcinetobactersp. AZ4C andTetraselmissp. in comparison to the control (microscope glass substratum without a ZnO coating). High mortality and low settlement ofB. neritinalarvae was observed on ZnO nanorod coatings subjected to light irradiation. In darkness, neither mortality nor enhanced settlement of larvae was observed. Larvae ofB. neritinawere not affected by Zn2+ions. The AF effect of the ZnO nanorod coatings was thus attributed to the reactive oxygen species (ROS) produced by photocatalysis. It was concluded that ZnO nanorod coatings effectively prevented marine micro and macrofouling in static conditions. [ABSTRACT FROM AUTHOR]

Outbreaks of foodborne illness attributed to the consumption of Salmonella-tainted cantaloupe have occurred repeatedly, but understanding of the ecology of Salmonella on cantaloupe fruit surfaces is limited. We investigated the interactions between Salmonella enterica Poona, the plant pathogenic bacterium Erwinia tracheiphila, and cantaloupe fruit. Fruit surfaces were inoculated at the natural cracking stage by spreading S. enterica and E. tracheiphila, 20 µl at 107 cfu/ml, independently or together, over a 2×2 cm rind area containing a crack. Microbial and microscopic analyses were performed at 0, 9 and 24 days post inoculation (DPI). Even at 24 DPI (fruit maturity) S. enterica was detected on 14% and 40% of the fruit inoculated with S. enterica alone and the two-pathogen mixture, respectively. However, the population of S. enterica declined gradually after initial inoculation. E. tracheiphila, inoculated alone or together with Salmonella, caused watersoaked lesions on cantaloupe fruit; but we could not conclude in this study that S. enterica survival on the fruit surface was enhanced by the presence of those lesions. Of fruit inoculated with E. tracheiphila alone and sampled at 24 DPI, 61% had watersoaked lesions on the surface. In nearly half of those symptomatic fruits the watersoaking extended into the sub-rind mesocarp, and E. tracheiphila was recovered from that tissue in 50% of the symptomatic fruit. In this work, E. tracheiphila internalized through natural cracks on developing fruits. S. enterica was never detected in the fruit interior (ca. 2–3 mm below rind surface) under the limited conditions of our experiments, but the possibility that it, or other human pathogens that contaminate fresh produce, might also do so should be investigated under a wider range of conditions and produce types. [ABSTRACT FROM AUTHOR]

A new disease of unknown bacterial aetiology has been observed in eucalyptus stands since 2009. It is characterized by die-back, wilting and lesions on the branches, petiole and midrib in association with macroscopic and microscopic bacterial ooze. To date, this disease has been observed in stands of clonal Eucalyptus saligna, E. grandis and E. urophylla x E. grandis hybrids and in E. dunnii seedling plantations in the states of São Paulo, Rio Grande do Sul and Mato Grosso do Sul. Considering the economic importance of eucalyptus plantations and the potential losses caused by this disease, this study aimed to identify and characterize the causal agent. Thirty-four strains were obtained from infected plants, which were collected in the field from four locations. The inoculation of detached leaves and intact rooted cuttings supported pathogenicity in eucalyptus. The phylogenetic analysis of four housekeeping genes (16S rDNA, gapA, recA and rpoB) as well as biochemical tests confirmed the identity of strains belonging to the species Erwinia psidii. This is the first report of E. psidii as the cause of wilt and die-back in Eucalyptus spp. in Brazil. [ABSTRACT FROM AUTHOR]