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Understanding the relative importance of reproductive isolating mechanisms across the speciation continuum remains an outstanding challenge in evolutionary biology. Here, we examine a common isolating mechanism, reproductive phenology, between plant sister taxa at different stages of adaptive divergence to gain insight into its relative importance during speciation. We study 17 plant taxa that have independently adapted to inhospitable serpentine soils, and contrast each with a nonserpentine sister taxon to form pairs at either ecotypic or species-level divergence. We use greenhouse-based reciprocal transplants in field soils to quantify how often flowering time (FT) shifts accompany serpentine adaptation, when FT shifts evolve during speciation, and the genetic versus plastic basis of these shifts. We find that genetically based shifts in FT in serpentine-adapted taxa are pervasive regardless of the stage of divergence. Although plasticity increases FT shifts in five of the pairs, the degree of plasticity does not differ when comparing ecotypic versus species-level divergence. FT shifts generally led to significant, but incomplete, reproductive isolation that did not vary in strength by stage of divergence. Our work shows that adaptation to a novel habitat may predictably drive phenological isolation early in the speciation process. [ABSTRACT FROM AUTHOR]

Hybrid lethality is a type of reproductive isolation in which hybrids die before maturation, due to the interaction between the two causative genes derived from each of the hybrid parents. The interspecific hybrid of Nicotiana suaveolens × Nicotiana tabacum is a model plant used in studies on hybrid lethality. While most of the progeny produced from such a cross die, some individuals grow normally and mature. Separately, a technique for producing mature hybrids by artificial culture has been developed. However, the mechanism by which hybrids overcome lethality, either spontaneously or by artificial culture, remains unclear. In the present study, we found that some hybrids that overcome lethality, either spontaneously or by artificial culture, lack the distal part of the Q chromosome, a region that includes the gene responsible for lethality. Quantitative polymerase chain reaction results suggested that the distal deletion of the Q chromosome, detected in some hybrid seedlings that overcome lethality, is caused by reciprocal translocations between homoeologous chromosomes. The results showed that chromosomal instability during meiosis in amphidiploid N. tabacum as well as during artificial culturing of hybrid seedlings is involved in overcoming hybrid lethality in interspecific crosses of the genus Nicotiana. [ABSTRACT FROM AUTHOR]

Many recent studies have addressed the mechanisms operating during the early stages of speciation, but surprisingly few studies have tested theoretical predictions on the evolution of strong reproductive isolation (RI). To help address this gap, we first undertook a quantitative review of the hybrid zone literature for flowering plants in relation to reproductive barriers. Then, using Populus as an exemplary model group, we analysed genome-wide variation for phylogenetic tree topologies in both early- and late-stage speciation taxa to determine how these patterns may be related to the genomic architecture of RI. Our plant literature survey revealed variation in barrier complexity and an association between barrier number and introgressive gene flow. Focusing on Populus, our genome-wide analysis of tree topologies in speciating poplar taxa points to unusually complex genomic architectures of RI, consistent with earlier genome-wide association studies. These architectures appear to facilitate the 'escape' of introgressed genome segments from polygenic barriers even with strong RI, thus affecting their relationships with recombination rates. Placed within the context of the broader literature, our data illustrate how phylogenomic approaches hold great promise for addressing the evolution and temporary breakdown of RI during late stages of speciation. [ABSTRACT FROM AUTHOR]

Polyploid speciation entails substantial and rapid postzygotic reproductive isolation of nascent species that are initially sympatric with one or both parents. Despite strong postzygotic isolation, ecological niche differentiation has long been thought to be important for polyploid success. Using biogeographic data from across vascular plants, we tested whether the climatic niches of polyploid species are more differentiated than their diploid relatives and if the climatic niches of polyploid species differentiated faster than those of related diploids. We found that polyploids are often more climatically differentiated from their diploid parents than the diploids are from each other. Consistent with this pattern, we estimated that polyploid species generally have higher rates of multivariate niche differentiation than their diploid relatives. In contrast to recent analyses, our results confirm that ecological niche differentiation is an important component of polyploid speciation and that niche differentiation is often significantly faster in polyploids. [ABSTRACT FROM AUTHOR]

Recently diverged species often show incomplete reproductive isolation and subsequently experience hybridization and introgression. The plant genus Mimulus includes many such examples of closely related taxa that prove useful for studying incipient speciation. However, Sandstedt et al. show that in contrast to other Mimulus species, species of the M. tilingii complex are characterized by strong postzygotic isolation mediated by multiple barriers. This finding highlights the diverse speciation histories of related plant groups. [ABSTRACT FROM AUTHOR]

Members of the genus Dickeya are plant pathogens that mostly cause soft‐rot diseases. Diversity within the genus has led to the recent description of three novel species (i.e. a mainly clonal D. solani of economic consequence in potatoes, D. aquatica from water samples and D. fangzhongdai isolated from necrotic pear trees in China). However, multilocus sequence analysis (MLSA) has highlighted the occurrence of seven isolates not related to the defined Dickeya species. These include a previously unclassified group of Dickeya strains isolated from monocotyledonous plants, Dickeya sp. S1, Dickeya sp. B16, and Dickeya sp. NCPPB 3274, as well as Dickeya sp. MK7, a strain isolated from water, and misassigned strains D. solani ND14, D. solani M005 and D. chrysanthemi M074. Here, it is reported that these isolates can be classified as D. fangzhongdai by using average nucleotide identity analysis and MLSA. However, variations in phenotypic characterization featuring colony morphology and carbon utilization assays revealed a diversity of bacterial isolates classified as D. fangzhongdai. Based on the results of the genomic analysis, the classification of Dickeya sp. S1, Dickeya sp. B16, Dickeya sp. MK7, Dickeya sp. NCPPB 3274 to D. fangzhongdai is proposed as well as the reclassification of D. solani ND14, D. solani M005 and D. chrysanthemi M074 to D. fangzhongdai. [ABSTRACT FROM AUTHOR]

Gene flow is one of the main factors shaping genetic diversity within and among tree populations, and occurs through pollen and seed dispersal. Recent findings of pollen-release asynchronies in distant populations of Scots pine (Pinus sylvestris L.) within Scotland suggest that gene dispersal among more distant populations might be less effective than previously thought. Limited gene dispersal is one of the major factors causing genetic structure for neutral markers, and pollen-release asynchrony could have driven isolation by distance (IBD) among Scottish populations. Previous studies of neutral markers found little differentiation among Scottish populations of Scots pine, however they did not consider IBD over the full Scottish range. We analysed data from 6 nuclear simple sequence repeats (SSR) and 5 chloroplast SSR loci in a total of 540 individuals of Scots pine from 18 populations across Scotland. Our aim was to assess contemporary levels and distribution of genetic variation and to test if the distribution of genetic diversity was consistent with IBD. We also analysed patterns of gene flow that could have contributed to the observed patterns of variation. Levels of genetic diversity were high, for both nuclear and chloroplast markers within populations, and there was no significant differentiation among populations. A weak signal of IBD was present. We found an increase in nuclear diversity towards the East along with greater gene flow in a West-East direction commensurate with the prevailing winds. Our findings suggest that this wind-driven gene flow is dominant over genetic drift and prevents differentiation among the Scottish populations. It may also counteract any pollen-release asynchronies among populations. [ABSTRACT FROM AUTHOR]

Background: Biological methods of polycyclic aromatic hydrocarbons (PAH) contamination elimination typically involve the transformation of contaminants to non-toxic materials by microorganisms and plants and appear to be the most effective methods available. Methods: In this study, Bacillus licheniformis and Bacillus mojavensis isolated from oil-contaminated soils were inoculated onto Festuca arundinacea seeds before planting in the pot and 3 weeks after planting by syringe injection into the rhizospheric zone in order to study the elimination of PAHs from Festuca’s rhizosphere in the greenhouse. Some physical and chemical properties of the soil, PAH concentrations, seeds germination percentage, root and shoot biomasses of the treated samples were examined. Results: The results showed that the treated samples inoculated with both bacteria had a significantly higher percentage of seed germination and root and shoot biomass compared to other treatments. The concentration of some PAHs reduced significantly (Pvalue < 0.05) in the rhizosphere of the treated samples inoculated with both bacteria compared to in contaminated soils. Concentrations of some PAHs (eg. Naphthalene, Phenanthrene, Benzo[a]anthracene and Dibenzo[a,h]anthracene) even reached below the detection limit of the method. The PAHs concentrations in the treated samples inoculated with bacteria was decreased significantly (Pvalue < 0.05). Therefore, the results showed the high efficiency of the Festuca and bacterial inoculation in eliminating PAHs from the soil. Conclusion: According to the results, the partnership of Festuca with B. licheniformis and B. mojavensis isolates displayed positive effect on PAHs dissipation and can be effective cleanup technology with high performance. [ABSTRACT FROM AUTHOR]

Black rot of sweetpotato, caused by Ceratocystis fimbriata, has recently reemerged as a significant threat to sweetpotato production in North Carolina and other states across the United States. This disease has historically been controlled largely through cultural management strategies and. in some cases, fungicide application. The sudden and destructive reemergence of this disease in 2015 created the need for rapidly evaluating disease control strategies. Genetic diversity of current C. fimbriata isolates infecting sweetpotato in North Carolina was assessed using ITS, TEF, and MAT-2 sequences. All 50 tested isolates were confirmed to be of a single mating type, MAT-2, based on PCR amplification. Alignment of ITS, TEF, and MAT-2 sequences revealed all isolates were identical at each locus. Fourteen common sweetpotato cultivars and advanced breeding lines were screened for black rot resistance using two isolates. None of the cultivars were completely resistant to the disease and most were equally susceptible. 'Stokes Purple' and 'Covington' were the least susceptible, but significantly (P < 0.05) differed only from 'Bellevue', the most susceptible cultivar. Sensitivity of 50 C. fimbriata isolates to difenoconazole, fludioxonil, thiabendazole, dicloran, azoxystrobin, pyraclostrobin, fenamidone, and fluazinam was evaluated in vitro. Difenoconazole, thiabendazole, and fluazinam were most effective in reducing mycelia growth. Postharvest fungicide application on black rot-infected roots provided similar results. Low efficacy of dicloran, as well as a range of EC5() values among isolates, suggests potential resistance to this commonly applied fungicide. Results obtained in this study provide current and useful information so that improved recommendations can be made to reduce losses in sweetpotato to black rot. [ABSTRACT FROM AUTHOR]

Eight fungal isolates (ELRF I to 8) were recovered from necrotic roots of Easter lilies, Lilium longiflorum cv. Nellie White, grown in a field in the U.S. Pacific Northwest. The eight fungal isolates were identified by sequencing and molecular phylogenetic analyses based on their ITS i DNA region. Five isolates were identified as Fusarium oxysporum, two as F. tricinctum, and one as Rhizoctonia sp. AG-I. This constitutes the first report of Rhizoctonia sp. AG-I infecting lilies worldwide and the first report of F. tricinctum infecting lilies in the United States. To study and validate their pathogenicity, pure cultures of each isolate were used to infect the roots of Easter lily plants growing in vitro. In addition, Easter lily plants growing in vitro were infected either with or without Pratylenchus penetrans, the root lesion nematode, prior to placing a culture plug of fungus 1 cm from a lily root. Pratylenchus penetrans is a nematode species commonly found in the sampled fields. The presence of both nematode and Rhizoctonia sp. AG-1 isolate ELRF 3 in infected lilies was evaluated by molecular analyses, confirming the infection of roots 3 days after inoculation, prior to development of disease symptoms. Necrosis and root rot developed more rapidly with all eight fungal isolates when there had been prior infection with P. penetrans, the major nematode parasitizing Easter lily roots in the field in Oregon. [ABSTRACT FROM AUTHOR]

The hop cultivar Cascade has been grown in the Pacific Northwestern U.S. and elsewhere with minimal input for management of powdery mildew (Podosphaera macularis) for nearly 15 years due to the putatively quantitative resistance in this cultivar. While partial resistance is generally thought to be more durable than qualitative resistance, in 2012, powdery mildew was reported on Cascade in Washington State. Field surveys conducted during 2013 to 2016 indicated increasing prevalence of powdery mildew on Cascade, as well as an increasing number of fungicide applications applied to this cultivar in Washington State. Nearly all isolates of P. macularis tested were able to infect Cascade in laboratory inoculations. However, the greatest number of colonies, most conidia produced, and the shortest latent period was only observed with isolates derived originally from Cascade, as compared with other isolates derived from other cultivars. Further, the enhanced aggressiveness of these isolates was only manifested on Cascade and not six other susceptible cultivars, further indicating a specific adaptation to Cascade by the isolates. There was no evidence of a known major R-gene in Cascade, as seven isolates of P. macularis with contrasting virulence all infected Cascade. Among 158 isolates obtained from hop yards planted to Cascade, only two (1.3%) were able to infect the cultivar Nugget, which possesses the resistance factor termed R6, indicating that isolates of P. macularis virulent on Nugget are largely distinct from those adapted to Cascade. Further, race characterization indicated Cascadeadapted isolates of P. macularis were able to overcome R-genes Rb, R3, and R5, but not other known R-genes. Therefore, multiple R-genes and other sources of partial resistance are expected to provide resistance to Cascadeadapted strains of the fungus. Given the plasticity of the powdery mildew fungus, breeding strategies for powdery mildew need to consider the potential for adaptation to both qualitative and partial resistance in the host. [ABSTRACT FROM AUTHOR]

The C-repeat binding factors (CBFs), also termed dehydration-responsive element-binding protein 1 (DREB1) family members, play crucial roles in the acquisition of stress tolerance, but in trees, the underlying mechanisms of stress tolerance remain elusive. To gain insight into these mechanisms, we isolated five CBF1 orthologs from four poplar sections (Populus spp.) and assessed their expression under drought, cold, heat and salt stress conditions. Globally induced expression in response to cold suggested a correlation between poplar CBF1 expression and the acquisition of cold tolerance. Responses that varied between sections may reflect section-specific stress tolerance mechanisms, suggesting an effect of ecological context on the development of CBF1- mediated stress tolerance in poplar. We then used a genome-wide search strategy in Populus trichocarpa to predict 2263 putative CBF target genes; the identified genes participate in multiple biological processes and pathways. Almost all of the putative target genes contained multiple cis-acting elements that mediate responses to various environmental and endogenous signals, consistent with an important role of CBF1s in an integrated cold regulatory network. Finally, analysis of an association population of 528 individuals of Populus simonii identified six single-nucleotide polymorphisms (false discovery rate Q < 0.10) significantly (P < 0.005) associated with malondialdehyde production and electrolyte leakage, suggesting the potential importance of PsCBF1 in the regulation of some membrane-related functions. Our findings provide new insights into the function of PsCBF1 and shed light on the CBF-mediated regulatory network in poplar. [ABSTRACT FROM AUTHOR]

In flowering plants, F1 hybrid seed lethality is a common outcome of crosses between closely related diploid species, but the genetic basis of this early-acting and potentially widespread form of postzygotic reproductive isolation is largely unknown., We intercrossed two closely related species of monkeyflower, Mimulus guttatus and Mimulus tilingii, to characterize the mechanisms and strength of postzygotic reproductive isolation. Then, using a reciprocal backcross design, we performed high-resolution genetic mapping to determine the genetic architecture of hybrid seed lethality and directly test for loci with parent-of-origin effects., We found that F1 hybrid seed lethality is an exceptionally strong isolating barrier between Mimulus species, with reciprocal crosses producing < 1% viable seeds. This form of postzygotic reproductive isolation appears to be highly polygenic, indicating that multiple incompatibility loci have accumulated rapidly between these closely related Mimulus species. It is also primarily caused by genetic loci with parent-of-origin effects, suggesting a possible role for imprinted genes in the evolution of Mimulus hybrid seed lethality., Our findings suggest that divergence in loci with parent-of-origin effects, which is probably driven by genomic coevolution within lineages, might be an important source of hybrid incompatibilities between flowering plant species. [ABSTRACT FROM AUTHOR]

Technological properties of two strains of Lactobacillus plantarum (B3 and B11) and one of Lactobacillus pentosus (B4), previously isolated from natural fermented green olives, have been studied in vitro. Acidifying ability, salt, temperature, and pH tolerances of all strains were found in the range reported for similar strains produced in Italy and optimal growth conditions were found to be 6.0-8.0 pH, 15-30°C temperature, and less than 6% NaCl. Moreover, all strains showed very good tolerance to common olive phenol content (0.3% total phenol) and high oleuropein-degrading capability. It was found that medium composition affected the bacterial oleuropein degradation. B11 strain grown in a nutrient-rich medium showed a lower oleuropein-degrading action than when it was cultivated in nutrient-poor medium. Furthermore, enzymatic activity assays revealed that oleuropein depletion did not correspond to an increase of hydroxytyrosol, evidencing that bacterial strains could efficiently degrade oleuropein via a mechanism different from hydrolysis. [ABSTRACT FROM AUTHOR]

Plants in the Meliaceae family are known to possess interesting biological activities, such as antimalaral, antihypertensive and antitumour activities. Previously, our group reported the plant-derived compound cycloart-24-ene-26-ol-3-one isolated from the hexane extracts of Aglaia exima leaves, which shows cytotoxicity towards various cancer cell lines, in particular, colon cancer cell lines. In this report, we further demonstrate that cycloart-24-ene-26-ol-3-one, from here forth known as cycloartane, reduces the viability of the colon cancer cell lines HT-29 and CaCO-2 in a dose- and time-dependent manner. Further elucidation of the compound’s mechanism showed that it binds to tumour necrosis factor-receptor 1 (TNF-R1) leading to the initiation of caspase-8 and, through the activation of Bid, in the activation of caspase-9. This activity causes a reduction in mitochondrial membrane potential (MMP) and the release of cytochrome-C. The activation of caspase-8 and -9 both act to commit the cancer cells to apoptosis through downstream caspase-3/7 activation, PARP cleavage and the lack of NFkB translocation into the nucleus. A molecular docking study showed that the cycloartane binds to the receptor through a hydrophobic interaction with cysteine-96 and hydrogen bonds with lysine-75 and -132. The results show that further development of the cycloartane as an anti-cancer drug is worthwhile. [ABSTRACT FROM AUTHOR]

The bark of Mimosa tenuiflora (Willd.) Poiret (Leguminosae family), popularly known as “jurema preta” in Brazil, is used by the population of Contendas of Sincorá (Bahia State, Brazil) for the treatment of coughs and wound healing. Thus, the aim of this study was to evaluate the antinociceptive and anti-inflammatory activities of the bark ethanol extract (EEMT) and solvent soluble fractions (hexane—H, DCM—D, EtOAc—E and BuOH—B) of the extract in vivo. Additionally, we synthesized 5,7-dihidroxy-4’-methoxyflavanone (isosakuranetin) and isolated the compound sakuranetin, and both compounds were also tested. The anti-inflammatory and antinociceptive assays performed were: writhing test; nociception induced by intraplantar formalin injection; leukocyte recruitment to the peritoneal cavity; evaluation of vascular permeability (Evans blue test); and evaluation of mechanical hypernociception (von Frey test). Production of TNF-α, IL-10, myeloperoxidase and the expression of ICAM-1 were also evaluated. Statistical analysis was performed by one-way ANOVA followed by the Bonferroni post-test (n = 8), with P < 0.05. The EEMT showed antinociceptive activities in writhing test (100–200 mg/kg), in the second phase of the formalin test (50–200 mg/kg), and in mechanical hypernociception (100 mg/kg). EEMT showed an anti-inflammatory effect by reducing neutrophil migration to the peritoneal cavity and in the plantar tissue detected by the reduction of myeloperoxidase activity (100 mg/kg), reduction of IL-10 levels and expression of ICAM-1 in the peritoneal exudate and the mesentery (100 mg/kg), respectively. The four soluble EEMT fractions showed good results in tests for antinociceptive (H, D, E, B) and anti-inflammation (H, D, E). Only sakuranetin showed reduction of the writhing and neutrophil migration (200 mg/kg). Thus, the EEMT and soluble fractions of M. tenuiflora bark demonstrated great antinociceptive and anti-inflammatory activities, as also sakuranetin. More studies should be conducted to elucidate the mechanism of action of this compound. To the best of our knowledge, this is the first report on the antinociceptive activity of the M. tenuiflora fractions and the bioactive isolated compound sakuranetin in vivo. [ABSTRACT FROM AUTHOR]

Eleven new furostanol saponins, typaspidosides B-L (1–11), one new spirostanol saponin, typaspidoside M (12), and five known spirostanol saponins, 25S-atropuroside (13), neoaspidistrin (14), (25S)-pratioside D1 (15), 25S-aspidistrin (16) and 25S-neosibiricoside (17) were isolated from the rhizomes of Aspidistra typica Baill. The structures of the new compounds were established using 1D and 2D NMR (1H-1H COSY, HMQC, HMBC and ROESY) spectroscopy, high resolution mass spectrometry, and chemical methods. The aglycones of 1–3 (unusual furostanol saponins with opened E ring type), 9 and 10 (the methoxyl substituent at C-23 position) were found, identified from natural products for the first time. Moreover, the anti-HIV activities of the isolated steroidal glycosides were assessed, and compounds 13, 14, 16 and 17 exhibited high active against HIV-1. [ABSTRACT FROM AUTHOR]

The aim of this work was to study the processes taking place during the enzymatic hydrolysis of seed globulins isolated from narrow-leaf (var. Zeus and Bojar) and yellow (var. Lord and Parys) lupin seeds species cultivated in Poland. In lupin seed globulins hydrolysis studies, there were used enzymes typical for the human gastrointestinal tract, such as: pepsin, pancreatin, trypsin and chymotrypsin. The obtained hydrolysates were assessed based on the results of electrophoretic, immunoblotting, as well as chromatographic separations. The evaluation of lupin seed globulins digestion susceptibility was supported by the bioinformatics analyses. Analysis of hydrolysates showed that the proteins present in globulins are completely hydrolysed by: pepsin, double digestion model (pepsin followed by pancreatin) or chymotrypsin. The high specificity of pancreatin and trypsin action results in limited lupin globulins hydrolysis. Protein fraction resistant to the action of these enzymes was γ-conglutin which also retains its antigenic properties. Its insensitivity to the hydrolysis might be associated with the formation of complexes with flavonoids which were released from other protein connections during digestion, as well as with relatively low number of cleavage sites for trypsin. The analysis of the three-dimensional structure of γ-conglutin enabled a very accurate description of the amino acid residues localisation, at which trypsin hydrolysis should occur. [ABSTRACT FROM AUTHOR]

The aim of this work is to study alternative biotechnological procedures to prepare green table olives. Specifically, by working on laboratory-scale system and under controlled conditions, the technological potential of enzymes from olive leaf and/or Lactobacillus plantarum strain (TB38) isolated from wine were assayed on green olives in comparison with spontaneous fermentation and 3 % NaOH treatment. The fermentation process (microbial count, pH, ethyl alcohol and the lactic and acetic acids, in the cover liquid medium) and the changes of phenolic fraction (total phenols, oleuropein and hydroxytyrosol, in the olive fruits) were checked weekly for 30 days. In the first week, olive leaf enzymes showed to be very effective in degrading the oleuropein; conversely, their action showed a decline in the subsequent days. Also the TB38 LAB strain showed a good oleuropeinolytic activity and acidifying capacity. However, the presence of undissolved olive leaf solid residue inhibited clearly the metabolism of LAB. [ABSTRACT FROM AUTHOR]

Stromules are stroma-containing tubules that have been observed to emanate from the main plastidic body in vivo. These structures have been shown to require cytoskeletal components for movement. Though numerous studies have shown a close association with the endoplasmic reticulum, nucleus, mitochondria, and other plastids, the mechanism of formation and their overall function remain unknown. A limiting factor in studying these structures has been the lack of a reconstituted system for in vitro stromule formation. In this study, stromule formation was induced in vitro by adding a plant extract fraction that is greater than 100 kDa to a population of isolated chloroplasts. Kinetic measurements show that stromule formation occurs within ~10 seconds after the addition of the plant extract fraction. Heat inactivation and apyrase treatment reveal that the stromule stimulating compound found in the extract fraction is a protein or protein complex 100 kDa or greater. The formation of the stromules in vitro with isolated chloroplasts and a concentrated fraction of cell extract opens an avenue for the biochemical dissection of this process that has heretofore been studied only in vivo. [ABSTRACT FROM AUTHOR]

The molecular characterization of a novel single-stranded RNA virus, obtained by next generation sequencing using Illumina platform, in a field grapevine isolate of the plant pathogenic fungus Botrytis , is reported in this work. The sequence comparison of this virus against the NCBI database showed a strong identity with RNA dependent RNA polymerases (RdRps) of plant pathogenic viruses belonging to the genus Ourmiavirus , therefore, this novel virus was named Botrytis ourmia-like virus (BOLV). BOLV has one open reading frame of 2169 nucleotides, which encodes a protein of 722 amino acids showing conserved domains of plant RNA viruses RdRps such as the most conserved GDD active domain. Our analyses showed that BOLV is phylogenetically closer to the fungal Narnavirus and the plant Ourmiavirus than to Mitovirus of the family Narnaviridae . Hence, we proposed that BOLV might represent the link between fungal viruses of the family Narnaviridae and the plant ourmiaviruses. [ABSTRACT FROM AUTHOR]

Background: Flavonoids have shown to exert multiple beneficial effects on human health, being also appreciated by both food and pharmaceutical industries. Citrus fruits are a key source of flavonoids, thus promoting studies to obtain them. Characteristics of these studies are the discrepancies among sample pretreatments and among extraction methods, and also the scant number of comparative studies developed so far. Objective: Evaluate the effect of both the sample pretreatment and the extraction method on the profile of flavonoids isolated from lemon. Results: Extracts from fresh, lyophilized and air-dried samples obtained by shaking extraction (SE), ultrasound-assisted extraction (USAE), microwave-assisted extraction (MAE) and superheated liquid extraction (SHLE) were analyzed by LC–QTOF MS/MS, and 32 flavonoids were tentatively identified using MS/MS information. ANOVA applied to the data from fresh and dehydrated samples and from extraction by the different methods revealed that 26 and 32 flavonoids, respectively, were significant (p≤0.01). The pairwise comparison (Tukey HSD; p≤0.01) showed that lyophilized samples are more different from fresh samples than from air-dried samples; also, principal component analysis (PCA) showed a clear discrimination among sample pretreatment strategies and suggested that such differences are mainly created by the abundance of major flavonoids. On the other hand, pairwise comparison of extraction methods revealed that USAE and MAE provided quite similar extracts, being SHLE extracts different from the other two. In this case, PCA showed a clear discrimination among extraction methods, and their position in the scores plot suggests a lower abundance of flavonoids in the extracts from SHLE. In the two PCA the loadings plots revealed a trend to forming groups according to flavonoid aglycones. Conclusions: The present study shows clear discrimination caused by both sample pretreatments and extraction methods. Under the studied conditions, liophilization provides extracts with higher amounts of flavonoids, and USAE is the best method for isolation of these compounds, followed by MAE and SE. On the contrary, the SHLE method was the less favorable to extract flavonoids from citrus owing to degradation. [ABSTRACT FROM AUTHOR]

Cotton is one of the most economically important cultivated crops. It is the major source of natural fiber for the textile industry and an important target for genetic modification for both biotic stress and herbicide tolerance. Therefore, the characterization of genes and regulatory regions that might be useful for genetic transformation is indispensable. The isolation and characterization of new regulatory regions is of great importance to drive transgene expression in genetically modified crops. One of the major drawbacks in cotton production is pest damage; therefore, the most promising, cost-effective, and sustainable method for pest control is the development of genetically resistant cotton lines. Considering this scenario, our group isolated and characterized the promoter region of a MCO (multicopper oxidase) from Gossypium hirsutum, named GhAO-like1 (ascorbate oxidase-like1). The quantitative expression, together with the in vivo characterization of the promoter region reveals that GhAO-like1 has a flower- and fruit-specific expression pattern. The GUS activity is mainly observed in stamens, as expected considering that the GhAO-like1 regulatory sequence is enriched in cis elements, which have been characterized as a target of reproductive tissue specific transcription factors. Both histological and quantitative analyses in Arabidopsis thaliana have confirmed flower (mainly in stamens) and fruit expression of GhAO-like1. In the present paper, we isolated and characterized both in silico and in vivo the promoter region of the GhAO-like1 gene. The regulatory region of GhAO-like1 might be useful to confer tissue-specific expression in genetically modified plants. [ABSTRACT FROM AUTHOR]

Colloidal silver nanoparticles (AgNPs) have attracted much attention in recent years as diagnostics and new drug delivery system in cancer medicine. To study the effects of plumbagin (PLB), a relatively non-toxic napthaquinone isolated from the roots of Plumbago indica in human cervical cancer cell line and developed a formulation to enhance its cytotoxic activities. Silver nanoparticles were synthesised by chemical reduction method and complexed with PLB. Both the AgNPs and the complex PLB-AgNPs were characterised by dynamic light scattering, high-resolution scanning electron microscopy and transmission electron microscopy. The amount of PLB and PLB-AgNPs internalised was determined by ultra-violet-visible spectrophotometer. Cell inhibition was determined by sulphorhodamine B assay. Mitotic index was determined by Wright-Giemsa staining. Apoptosis induction was assessed by western blot using cleaved poly adenosine diphosphate-ribose polymerase antibody. The scanning electron microscope analysis indicated an average particle size of 32 ± 8 nm in diameter. Enhanced internalisation of PLB into the HeLa cells was observed in PLB-AgNPs. PLB inhibited proliferation of cells with IC50 value of about 18 ± 0.6 µM and blocked the cells at mitosis in a concentration-dependent manner. PLB also inhibited the post-drug exposure clonogenic survival of cells and induced apoptosis. The antiproliferative, antimitotic and apoptotic activities were also found to be increased when cells were treated with PLB-AgNPs. The authors results support the idea that AgNP could be a promising and effective drug delivery system for enhanced activity of PLB in cancer treatment. [ABSTRACT FROM AUTHOR]

A rice chlorophyll-deficient mutant w67 was isolated from an ethyl methane sulfonate (EMS)–induced IR64 (Oryza sativa L. ssp. indica) mutant bank. The mutant exhibited a distinct yellow-green leaf phenotype in the whole plant growth duration with significantly reduced levels of chlorophyll and carotenoid, impaired chloroplast development and lowered capacity of photosynthesis compared with the wild-type IR64. Expression of a number of genes associated with chlorophyll metabolism, chloroplast biogenesis and photosynthesis was significantly altered in the mutant. Genetic analysis indicated that the yellow-green phenotype was controlled by a single recessive nuclear gene located on the short arm of chromosome 3. Using map-based strategy, the mutation was isolated and predicted to encode a chloroplast signal recognition particle 43 KD protein (cpSRP43) with 388 amino acid residuals. A single base substitution from A to T at position 160 resulted in a premature stop codon. OscpSRP43 was constitutively expressed in various organs with the highest level in the leaf. Functional complementation could rescue the mutant phenotype and subcellular localization showed that the cpSRP43:GFP fusion protein was targeted to the chloroplast. The data suggested that Oryza sativa cpSRP43 (OscpSRP43) was required for the normal development of chloroplasts and photosynthesis in rice. [ABSTRACT FROM AUTHOR]

PREMISE OF THE STUDY: Recent reviews of reproductive isolation (RI) in plants propose that boundaries between closely related species are maintained predominantly through prezygotic mechanisms. However, few experimental studies have explored how boundaries are maintained in long-lived species. Hawaiian Cyrtandra presents an intriguing challenge to our understanding of RI, as it comprises 60 shrub or small tree species that are almost exclusively restricted to wet forests, where sympatry of multiple species is common. METHODS: We assessed the relative strengths of pre- and postzygotic barriers among four species of Cyrtandra occurring at the extremes of the main Hawaiian Island's natural island-age gradient, Kaua'i (4.7 Myr) and Hawai'i Island (0.6 Myr), to contrast the strengths and stages of reproductive isolation among species at different stages of divergence. KEY RESULTS: A combination of F1 seed germination, F1 seedling survival, and F1 seedling growth isolated (61-91%) three of the species from sympatric relatives. In contrast, the fourth species was isolated (59%) from its sympatric relative through phenological differences alone. Significant postzygotic barriers in between-island crosses were also observed in one species. CONCLUSIONS: Results suggest that boundaries between sympatric Cyrtandra species in Hawaii are maintained predominantly through postzygotic barriers. Observations from between-island crosses indicate that postzygotic barriers can arise in allopatry, which may be important in the initial divergence of populations. Future studies of RI in Cyrtandra should include a broader range of species to determine if postzygotic isolating barriers are foremost in the maintenance of species boundaries in this large genus. [ABSTRACT FROM AUTHOR]

PREMISE OF THE STUDY: Glacial cycles have influenced the genetic structure of many species. In addition to facilitating genetic divergence, isolation in multiple glacial refugia may have contributed to the development of genetic incompatibility and reproductive isolation. We examined the phylogeography of Campanulastrum americanum, a monocarpic herbaceous plant that exhibits strong intraspecific reproductive isolation, to determine whether the current genetic structure reflects a history of multiple glacial refugia. METHODS: Chloroplast loci and nuclear RAD sequencing were used to characterize the range-wide phylogeography of C. americanum, in order to determine locations of potential glacial refugia and recolonization routes. Potential locations of refugia during the Last Glacial Maximum were also identified using ecological niche modeling. KEY RESULTS: Together, the chloroplast and nuclear phylogenies found support for three geographically structured, genetically divergent lineages, among which gene flow appears to be restricted. The distribution of these lineages indicates that C. americanum survived the Last Glacial Maximum in at least three refugia located in the Appalachians and on the Atlantic and Gulf coasts. The ecological niche model also supported the existence of multiple refugia. CONCLUSIONS: The isolation of populations of C. americanum in multiple refugia has led to a degree of phylogeographic structure greater than that found in most previously studied plants in eastern North America, which may be attributable to its short generation time. Reproductively isolated populations of C. americanum belong to divergent lineages, which suggests that survival in multiple glacial refugia contributed to the development of reproductive isolation in this species. [ABSTRACT FROM AUTHOR]

We studied the effect of Silicon (Si) on Casparian band (CB) development, chemical composition of the exodermal CB and Si deposition across the root in the Si accumulators rice and maize and the Si non-accumulator onion. Plants were cultivated in nutrient solution with and without Si supply. The CB development was determined in stained root cross-sections. The outer part of the roots containing the exodermis was isolated after enzymatic treatment. The exodermal suberin was transesterified with MeOH/BF3 and the chemical composition was measured using gas chromatography-mass spectroscopy (GC-MS) and flame ionization detector (GC-FID). Laser ablation-inductively coupled plasma-mass spectroscopy (LA-ICP-MS) was used to determine the Si deposition across root cross sections. Si promoted CB formation in the roots of Si-accumulator and Si non-accumulator species. The exodermal suberin was decreased in rice and maize due to decreased amounts of aromatic suberin fractions. Si did not affect the concentration of lignin and lignin-like polymers in the outer part of rice, maize and onion roots. The highest Si depositions were found in the tissues containing CB. These data along with literature were used to suggest a mechanism how Si promotes the CB development by forming complexes with phenols. [ABSTRACT FROM AUTHOR]

Understanding the drivers of plant-insect interactions is still a key issue in terrestrial ecology. Here, we used 30 well-defined plant-herbivore assemblages to assess the effects of host plant phylogenetic isolation and origin (native vs. exotic) on the species richness, composition and specialization of the insect herbivore fauna on co-occurring plant species. We also tested for differences in such effects between assemblages composed exclusively of exophagous and endophagous herbivores. We found a consistent negative effect of the phylogenetic isolation of host plants on the richness, similarity and specialization of their insect herbivore faunas. Notably, except for Jaccard dissimilarity, the effect of phylogenetic isolation on the insect herbivore faunas did not vary between native and exotic plants. Our findings show that the phylogenetic isolation of host plants is a key factor that influences the richness, composition and specialization of their local herbivore faunas, regardless of the host plant origin. [ABSTRACT FROM AUTHOR]

Background: Berberine acts primarily as an important active ingredient in Coptis chinensis and has been traditionally applied in clinical treatment. Nevertheless, little information has been released about C. chinensis, as far as functional genes and biosynthetic pathway of berberine are concerned. Here, we isolated a novel (S)-canadine synthase gene (designated as CAS-1) from C. chinensis by using RT-PCR and RACE techniques. Results: Bioinformatics analysis showed that the cDNA is 1942 bp in length with a complete open reading frame (ORF) of 1476 bp, and the ORF encodes a polypeptide of 491 amino acids with a calculated molecular mass of 55.29 kDa and a pI value of 8.92. Real-time quantitative PCR analysis showed that CcCAS-1 was constitutively expressed in leaf, petiole and rhizome tissues, especially in the leaves of C. chinensis. However, the results of berberine content in different tissues by high-performance liquid chromatography with photodiode array detection (HPLC-DAD)method showed that the leaves and the petiole tissues have similar content of berberine. Conclusions:We found that the berberine content in the rhizome was seven times (more or less) than that in the leaves and the petioles. In addition, the full length coding sequence of CcCAS-1 was inserted into pET-32a and was successfully expressed in Escherichia coli, laying a solid foundation for protein purification, activity assay and multi-clonal antibody preparation. Together, our data suggest that CcCAS-1 is a novel heme-thiolate enzyme essential for berberine biosynthesis in C. chinensis. [ABSTRACT FROM AUTHOR]

Cherry plum is a popular ornamental tree worldwide and most cultivars are selected for purple foliage. Here, we report the investigation of molecular mechanism underlying red pigmentation in purple-leaf plum ‘Ziyeli’ (Prunus cerasifera Ehrhar f. atropurpurea (Jacq.) Rehd.), which shows red color pigmentation in fruit (flesh and skin) and foliage. Six anthocyanin-activating MYB genes, designated PcMYB10.1 to PcMYB10.6, were isolated based on RNA-Seq data from leaves of cv. Ziyeli. Of these PcMYB10 genes, five (PcMYB10.1 through PcMYB10.5) show distinct spatial and temporal expression patterns, while the PcMYB10.6 gene is highly expressed in all the purple-coloured organs of cv. Ziyeli. Constitutive activation of PcMYB10.6 is closely related to red pigmentation in the leaf, fruit (flesh and skin), and sepal. However, the PcMYB10.6 activation cannot induce red pigmentation in the petal of cv. Ziyeli during late stages of flower development due to due to a lack of expression of PcUFGT. The inhibition of red pigmentation in the petal of cherry plum could be attributed to the high-level expression of PcANR that directs anthocyanidin flux to proanthocyanidin biosynthesis. In addition, PcMYB10.2 is highly expressed in fruit and sepal, but its expression cannot induce red pigmentation. This suggests the PcMYB10 gene family in cherry plum may have diverged in function and PcMYB10.2 plays little role in the regulation of red pigmentation. Our study provides for the first time an example of constitutive activation of an anthocyanin-activating MYB gene in Prunus although its underlying mechanism remains unclear. [ABSTRACT FROM AUTHOR]

Bacterial leaf spot (BLS) disease, caused by Xanthomonas campestris pv. vitians (Xcv) has become an increasingly damaging disease in the lettuce production areas of the United States. To understand the nature of the outbreaks of this disease, the pathogenic variations for causing disease were evaluated on 29 lettuce cultivars and germplasm lines using three Xcv isolates recovered in different years from the Everglades Agriculture Area (EAA) of Florida. Significant differences were shown in both the BLS incidences and disease severities among the three Xcv isolates, and the rank from high virulence to less severity was L7 > JF196 > NF1. Our results suggest that the pathogenic variations of the isolates may have been associated with the epidemic outbreaks of BLS in EAA. Among the 29 lettuce genotypes, the host plant resistance was characterized by specific host genotype and Xcv isolate interactions. The leaf lettuce PI358001-1 was consistently in the high resistant category to all three Xcv isolates, and is a promising resistant source for development of resistant cultivars. [ABSTRACT FROM AUTHOR]

* Premise of the study: The mating system is an important component of the complex set of reproductive isolation barriers causing plant speciation. However, empirical evidence showing that the mating system may promote reproductive isolation in co-occurring species is limited. The mechanisms by which the mating system can act as a reproductive isolation barrier are also largely unknown. * Methods: Here we studied progeny arrays genotyped with microsatellites and patterns of stigma-anther separation (herkogamy) to understand the role of mating system shifts in promoting reproductive isolation between two hybridizing taxa with porous genomes, Pitcairnia albiflos and P. staminea (Bromeliaceae). * Key results: In P. staminea, we detected increased selfing and reduced herkogamy in one sympatric relative to two allopatric populations, consistent with mating system shifts in sympatry acting to maintain the species integrity of P. staminea when in contact with P. albiflos. * Conclusions: Mating system variation is a result of several factors acting simultaneously in these populations. We report mating system shifts as one possible reproductive barrier between these species, acting in addition to numerous other prezygotic (i.e., flower phenology and pollination syndromes) and postzygotic barriers (Bateson-Dobzhansky-Muller genetic incompatibilities). [ABSTRACT FROM AUTHOR]

An intracellular nitrilase (Nit1) with cyanide-degrading activity was isolated from Trichoderma harzianum VSL291, cultivated on benzonitrile as the sole carbon source. Nit1 was purified to homogeneity by ion exchange and gel filtration chromatography with a recovery of 7.15% and a fold of 22.5. The molecular weight was estimated to be 47.7 kDa and the purified enzyme was sequenced with a system of liquid chromatography and mass spectrometry (LC-MS). The enzyme consists of 436 amino acids with a predicted molecular weight of 47.088 kDa. The sequence revealed conserved domains for a nitrilase super family such as putative active and binding sites and a Glu-Lys-Cys catalytic triad. Nit1 exhibited maximum activity (19.6 U mg-1) at 40 °C and a pH of 7.5. Nit1 had a strong inhibition in the presence of Al³+, Cu2+, Zn2+, and Ag+ ions and was able to degrade KCN completely at 0.02 mmol/L, 0.05 mmol/L, and 0.1 mmol/L in 15 min, 40 min, and 45 min, respectively. The effect on KCN (0.02 mmol/L) degradation was tested in the presence of Cu2+ and Ag+ ions (0.025 mmol/L to 1.0 mmol/L) and the enzymatic activity was not affected significantly at 0.025 mmol/L, 0.075 mmol/L, and 0.125 mmol/L concentrations. However, when both ions were combined, the activity of the enzyme decreased significantly. [ABSTRACT FROM AUTHOR]

In this study, cellulose nanofibrils (CNFs) were successfully isolated from coconut palm petiole residues falling off naturally with chemical pretreatments and mechanical treatments by a grinder and a homogenizor. FTIR spectra analysis showed that most of hemicellulose and lignin were removed from the fiber after chemical pretreatments. The compositions of CNFS indicated that high purity of nanofibrils with cellulose contain more than 95% was obtained. X-ray diffractogram demonstrated that chemical pretreatments significantly increased the crystallinity of CNFs from 38.00% to 70.36%; however, 10-15 times of grinding operation followed by homogenizing treatment after the chemical pretreatments did not significantly improve the crystallinity of CNFs. On the contrary, further grinding operation could destroy crystalline regions of the cellulose. SEM image indicated that high quality of CNFs could be isolated from coconut palm petiole residues with chemical treatments in combination of 15 times of grinding followed by 10 times of homogenization and the aspect ratio of the obtained CNFs ranged from 320 to 640. The result of TGA-DTG revealed that the chemical-mechanical treatments improved thermal stability of fiber samples, and the CNFs with 15 grinding passing times had the best thermal stability. This work suggests that the CNFs can be successfully extracted from coconut palm petiole residues and it may be a potential feedstock for nanofiber reinforced composites due to its high aspect ratio and crystallinity. [ABSTRACT FROM AUTHOR]

The process of plant speciation often involves the evolution of divergent ecotypes in response to differences in soil water availability between habitats. While the same set of traits is frequently associated with xeric/mesic ecotype divergence, it is unknown whether those traits evolve independently or if they evolve in tandem as a result of genetic colocalization either by pleiotropy or genetic linkage., The self-fertilizing C4 grass species Panicum hallii includes two major ecotypes found in xeric (var. hallii) or mesic (var. filipes) habitats. We constructed the first linkage map for P. hallii by genotyping a reduced representation genomic library of an F2 population derived from an intercross of var. hallii and filipes. We then evaluated the genetic architecture of divergence between these ecotypes through quantitative trait locus (QTL) mapping., Overall, we mapped QTLs for nine morphological traits that are involved in the divergence between the ecotypes. QTLs for five key ecotype-differentiating traits all colocalized to the same region of linkage group five. Leaf physiological traits were less divergent between ecotypes, but we still mapped five physiological QTLs. We also discovered a two-locus Dobzhansky-Muller hybrid incompatibility., Our study suggests that ecotype-differentiating traits may evolve in tandem as a result of genetic colocalization. [ABSTRACT FROM AUTHOR]

Ethanol Crude extract of Cosicinium fenestratum stems (Gaertre) Coleb (Menispermaceae) exhibited inhibiting activity against seven plant pathogenic fungi and one antagonistic fungus when they were tested using the dilution method. Ethanolic crude extract of C. fenestratum stems was then fractionated by column chromatography using six organic solvents, and subsequent antimicrobial activity evaluation revealed that only the fraction eluted with methanol exhibited inhibitory activity against the tested phytopathogenic fungi. Further re-fractionation resulted in 60 subfractions eluted with 60 solvent combination systems of increased polarity, that were also evaluated for their antimicrobial effect, being the subfractions eluted with mixture of acetone: chloroform and chloroform: methanol identified as the most active against tested plant pathogenic fungi. The chromatographic profile of the active subfractions revealed a common metabolite, which was isolated by PTLC (Preparative Thin Layer Chromatography) and identified as berberine through NMR (Nuclear Magnetic Resonance) analysis. Berberine displayed relevant antimicrobial activity against several of the tested plant pathogenic fungi being identified as the main active constitutuent from the active subfractions. [ABSTRACT FROM AUTHOR]

5′-Methylthioadenosine (MTA) nucleosidase (MTN) plays a key role in the methionine (Met) recycling pathway of plants. Here, we report the isolation of the 1158 bp full-length, cDNA sequence encoding tetraploid black locust ( Robinia pseudoacacia L.) MTN ( TrbMTN ), which contains an open reading frame of 810 bp that encodes a 269 amino acid protein. The amino acid sequence of TrbMTN has more than 88% sequence identity to the MTNs from other plants, with a closer phylogenetic relationship to MTNs from legumes than to MTNs from other plants. Subcellular localization analysis revealed that the TrbMTN gene localizes mainly to the cell membrane and cytoplasm of onion epidermal cells. Indole-3-butyric acid (IBA)-treated cuttings showed higher TrbMTN transcript levels than untreated control cuttings during root primordium and adventitious root formation. TrbMTN and key Met cycle genes showed differential expression in shoots, leaves, stems, and roots, with the highest expression observed in stems. IBA-treated cuttings also showed higher TrbMTN activity than control cuttings during root primordium and adventitious root formation. These results indicate that TrbMTN gene might play an important role in the regulation of IBA-induced adventitious root development in tetraploid black locust cuttings. [ABSTRACT FROM AUTHOR]

Pollinator-mediated reproductive isolation is a major factor in driving the diversification of flowering plants. Studies of floral traits involved in reproductive isolation have focused nearly exclusively on visual signals, such as flower color. The role of less obvious signals, such as floral scent, has been studied only recently. In particular, the genetics of floral volatiles involved in mediating differential pollinator visitation remains unknown. The bumblebee-pollinated Mimulus lewisii and hummingbird-pollinated Mimulus cardinalis are a model system for studying reproductive isolation via pollinator preference. We have shown that these two species differ in three floral terpenoid volatiles - d-limonene, β-myrcene, and E-β-ocimene - that are attractive to bumblebee pollinators. By genetic mapping and in vitro analysis of enzyme activity we demonstrate that these interspecific differences are consistent with allelic variation at two loci, LIMONENE- MYRCENE SYNTHASE ( LMS) and OCIMENE SYNTHASE ( OS). Mimulus lewisii LMS ( Ml LMS) and OS ( Ml OS) are expressed most strongly in floral tissue in the last stages of floral development. Mimulus cardinalis LMS ( Mc LMS) is weakly expressed and has a nonsense mutation in exon 3. Mimulus cardinalis OS ( Mc OS) is expressed similarly to Ml OS, but the encoded Mc OS enzyme produces no E-β-ocimene. Recapitulating the M. cardinalis phenotype by reducing the expression of Ml LMS by RNA interference in transgenic M. lewisii produces no behavioral difference in pollinating bumblebees; however, reducing Ml OS expression produces a 6% decrease in visitation. Allelic variation at the OCIMENE SYNTHASE locus is likely to contribute to differential pollinator visitation, and thus promote reproductive isolation between M. lewisii and M. cardinalis. OCIMENE SYNTHASE joins a growing list of 'speciation genes' ('barrier genes') in flowering plants. [ABSTRACT FROM AUTHOR]

We describe the in planta function of an Arabidopsis J protein gene, AtJ1. We isolated an ABA-hypersensitive mutant, named as793 (ABA-hypersensitive 793), by activation tagging screen. Analysis of the mutant revealed that T-DNA was inserted into the gene encoding AtJ1, thereby abolishing its expression. as793 plants grew very poorly under normal growth conditions; their seed setting efficiency was lower and their flowering was delayed compared with wild-type plants. Moreover, as793 plants were ABA hypersensitive and drought tolerant. In parallel analyses, we found that another AtJ1 knockout mutant acquired from the Arabidopsis Stock Center exhibited the same phenotypes as as793 and that its phenotypes could be complemented by the wild-type AtJ1. At the molecular level, we found that the expression of a large number of genes involved in embryogenesis, flowering time control and stress response was altered in as793. Others previously reported that AtJ1 is a mitochondrial protein involved in thermotolerance. Our results further indicate that AtJ1 is essential for normal plant growth, from embryogenesis to flowering and seed setting. Additionally, the ABA hypersensitivity of as793 suggests that AtJ1 may function as a negative regulator of ABA response. [ABSTRACT FROM AUTHOR]

Gibberellins (GAs) are important in the floral regulatory networks of angiosperm plants. Several lines of evidence suggest that GAs also play a pivotal role in conifer male and female cone development. To gain new insights into the GA metabolism pathway in conifer trees and the role of GA metabolism in male and female cone development, we identified GA metabolism genes in Pinus tabuliformis. These included one PtCPS gene, one PtKS gene, one PtKO gene, TWO PtKAO genes, one PtGA20ox gene, two PtGA3ox genes and 12 PtGA2ox genes. According to phylogenetic analysis, the GA biosynthesis pathway evolved after the divergence of mosses from ferns, but the GA-deactivating gene family underwent divided expansion after divergence of the angiosperms from gymnosperms. However, the active sites of all GA metabolism enzymes were conserved during the evolution of land plants. During male and female cone development of P. tabuliformis, the expression of most of the PtGA2ox genes, especially PtGA2ox10, was higher than GA biosynthesis genes. However, the expression of PtKAO1 in cones peaked at a very early developmental stage. The expression pattern of GA metabolism genes indicated that GAs play different roles at the early and late stages of cone development. [ABSTRACT FROM AUTHOR]

Ninety seven Rhizoctonia isolates were collected from different Brassica species with typical Rhizoctonia symptoms in different provinces of Vietnam. The isolates were identified using staining of nuclei and sequencing of the rDNA-ITS barcoding gene. The majority of the isolates were multinucleate R. solani and four isolates were binucleate Rhizoctonia belonging to anastomosis groups (AGs) AG-A and a new subgroup of A-F that we introduce here as AG-Fc on the basis of differences in rDNA-ITS sequence. The most prevalent multinucleate AG was AG 1-IA (45.4% of isolates), followed by AG 1-ID (17.5%), AG 1-IB (13.4%), AG 4-HGI (12.4%), AG 2-2 (5.2%), AG 7 (1.0%) and an unknown AG related to AG 1-IA and AG 1-IE that we introduce here as AG 1-IG (1.0%) on the basis of differences in rDNA-ITS sequence. AG 1-IA and AG 1-ID have not been reported before on Brassica spp. Pathogenicity tests revealed that isolates from all AGs, except AG-A, induced symptoms on detached leaves of several cabbage species. In in vitro tests on white cabbage and Chinese cabbage, both hosts were severely infected by AG 1-IB, AG 2-2, AG 4-HGI, AG 1-IG and AG-Fc isolates, while under greenhouse conditions, only AG 4-HGI, AG 2-2 and AG-Fc isolates could cause severe disease symptoms. The occurrence of the different AGs seems to be correlated with the cropping systems and cultural practices in different sampling areas suggesting that agricultural practices determine the AGs associated with Brassica plants in Vietnam. [ABSTRACT FROM AUTHOR]

Summary Reinforcement, the process of increased reproductive isolation due to selection against hybrids, is an important mechanism by which natural selection contributes to speciation [ 1 ]. Empirical studies suggest that reinforcement has generated reproductive isolation in many taxa (reviewed in [ 2–4 ]), and theoretical work shows it can act under broad selective conditions [ 5–11 ]. However, the strength of selection driving reinforcement has never been measured in nature. Here, we quantify the strength of reinforcing selection in the Texas wildflower Phlox drummondii using a strategy that weds a population genetic model with field data. Reinforcement in this system is caused by variation in two loci that affect flower color [ 12 ]. We quantify sharp clines in flower color where this species comes into contact with its congener, Phlox cuspidata . We develop a spatially explicit population genetic model for these clines based on the known genetics of flower color. We fit our model to the data using likelihood, and we searched parameter space using Markov chain Monte Carlo methods. We find that selection on flower color genes generated by reinforcement is exceptionally strong. Our findings demonstrate that natural selection can play a decisive role in the evolution of reproductive isolation through the process of reinforcement. [ABSTRACT FROM AUTHOR]

Despite extensive theory, little is known about the empirical accumulation and evolutionary timing of mutations that contribute to speciation. Here we combined QTL (Quantitative Trait Loci) analyses of reproductive isolation, with information on species evolutionary relationships, to reconstruct the order and timing of mutations contributing to reproductive isolation between three plant (Solanum) species. To evaluate whether reproductive isolation QTL that appear to coincide in more than one species pair are homologous, we used cross-specific tests of allelism and found evidence for both homologous and lineage-specific (non-homologous) alleles at these co-localized loci. These data, along with isolation QTL unique to single species pairs, indicate that >85% of isolation-causing mutations arose later in the history of divergence between species. Phylogenetically explicit analyses of these data support non-linear models of accumulation of hybrid incompatibility, although the specific best-fit model differs between seed (pairwise interactions) and pollen (multi-locus interactions) sterility traits. Our findings corroborate theory that predicts an acceleration (‘snowballing’) in the accumulation of isolation loci as lineages progressively diverge, and suggest different underlying genetic bases for pollen versus seed sterility. Pollen sterility in particular appears to be due to complex genetic interactions, and we show this is consistent with a snowball model where later arising mutations are more likely to be involved in pairwise or multi-locus interactions that specifically involve ancestral alleles, compared to earlier arising mutations. [ABSTRACT FROM AUTHOR]

Grain samples of 14 Egyptian wheat cultivars were tested for seed-borne fungi. The deep freezing method was used. Five seed-borne fungi viz., Aspergillus flavus, A. niger, Curvularia lunata, Fusarium moniliforme and Penicillium chrysogenum were isolated from the wheat cultivars viz., Bani Suef 4, Bani Suef 5, Gemmiza 7, Gemmiza 9, Gemmiza 10, Giza 168, Misr 1, Misr 2, Sakha 93, Sakha 94, Shandaweel 1, Sids 1, Sids 2 and Sids 3. A. flavus, A. niger and F. moniliforme were the most prevalent fungal species. Their incidence ranged from 21.0-53.5%, 16.0-37.5%, and 12.0-31.0%, respectively. The antifungal potential of water extracts from aerial parts of five wild medicinal plants (Asclepias sinaica, Farsetia aegyptia, Hypericum sinaicum, Phagnalon sinaicum, and Salvia aegyptiaca) were collected from the Sinai Peninsula, Egypt. The antifungal potential of water extracts from the aerial parts of these five plants were tested in the laboratory against the dominant fungi isolated from the wheat cultivars. All the aqueous plant extracts significantly (p ≤ 0.05) reduced the incidence of the tested seed-borne fungi. But the extract of Asclepias sinaica exhibited the most antifungal activity on tested fungi at all concentrations used when compared with other plant extracts. Maximum infested grain germination was observed in Giza 168 and minimum in Bani Suef 5. Treating grains with plant extract of A. sinaica (10%) enhanced the percentage of grain germination of all cultivars in both laboratory and pot experiments. Maximum root and shoot length of seedlings was recorded in Bani Suef 4 during fungal infestation or treatment by plant extract. For one hour before sowing or storage, the aqueous extract of A. sinaica can be used to treat wheat grains, to reduce the fungal incidence. Aqueous extracts of the aerial parts of selected medicinal plants, particularly A. sinaica, are promising for protecting Egyptian wheat grain cultivars against major seed-borne fungi. The aqueous extracts are expected to improve crops. [ABSTRACT FROM AUTHOR]

The Aspergillus flavus population structure from maize kernels was examined. During 2011, samples were collected from two main grain maize production areas in Iran (Fars and Ardebil provinces), shortly before harvest. One-hundred nine A. flavus isolates were recovered on Dichloran Rose Bengal Chloramphenicole (DRBC) agar and Aspergillus flavus/parasiticus medium (AFPA) and grouped into morphotypes and Vegetative Compatibility Groups (VCGs) based on morphological (e.g. sclerotia production), physiological (e.g. aflatoxin-producing ability) and genetic criteria (e.g. heterokaryosis). In general, morphotype and VCG composition were highly dissimilar in both provinces. In total, 43.8% and 44.3% of A. flavus isolates from Ardebil and Fars, respectively, produced sclerotia. Sclerotia producers were identified as A. flavus L and S strain morphotypes in Ardebil (66.7% and 33.3%, respectively) and Fars (29.6% and 70.4%, respectively). Furthermore, 71 isolates (65.1%) were able to produce aflatoxin (Ardebil 40.8%, Fars 59.2%). The aflatoxin values were categorized into four different classes (< 10, 10-100, 100-1,000 and > 1,000 ppb). In total, 51 aflatoxin producing isolates of A. flavus (Ardebil n = 22, Fars n = 29) were assigned into 26 VCGs by complementation of nit auxotrophs on nitrate medium. None of the A. flavus isolates from Ardebil complemented with any isolates from Fars. Genetic diversity of A. flavus isolates was 59.1% and 41.8% for Ardebil and Fars, respectively. The different geographical adaptation and genetic make-up of A. flavus isolates may be due to different climatic conditions, soil types and crop sequences in both maize production areas. [ABSTRACT FROM AUTHOR]

The paper presents the results of the study performed with aims to determine the presence and diversity of Phytophthora species on maple trees in Serbia. Due to high aggressiveness and their multicyclic nature, presence of these pathogens is posing significant threat to forestry and biodiversity. In total, 29 samples of water, soil and tissues were taken from 10 different localities, and six different maple hosts were tested. After the isolation tests, 17 samples from five different maple hosts were positive for the presence of Phytophthora spp., and 31 isolates were obtained. After the detailed morphological and physiological classification, four distinct groups of isolates were separated. DNA was extracted from selected representative isolates and molecular identification with sequencing of ITS region was performed. Used ITS4 and ITS6 primers successfully amplified the genomic DNA of chosen isolates and morphological identification of obtained isolates was confirmed after the sequencing. Four different Phytophthora species were detected, including P. cactorum, P. gonapodyides, P. plurivora and P. lacustris. The most common isolated species was homothallic, and with very variable and semipapillate sporangia, P. plurivora with 22 obtained isolates. This is the first report of P. plurivora and P. gonapodyides on A. campestre, P. plurivora and P. lacustris on Acer heldreichii and first report of P. lacustris on A. pseudoplatanus and A. tataricum in Serbia. [ABSTRACT FROM AUTHOR]

Reproductive isolation is a fundamental requirement for speciation and includes several sequential stages. Few studies have determined the relative contributions of pre- and post-zygotic reproductive isolation in plants, especially between relative species with clear differentiation in flower form. To investigate the mechanisms responsible for reproductive isolation in sympatric Mussaenda pubescens var. alba and Mussaenda shikokiana (Rubiaceae) in Guangxi Province, China, we made observations of flowering phenology, patterns of insect visitation, and conducted pollination experiments, including artificial hybridization. The two species had overlapping flowering times and were pollinated by overlapping pollinators; however, their relative importance differed significantly with M. pubescens visited more commonly by bees and M. shikokiana more frequently by butterflies. Using vegetative and floral characters and molecular evidence based on nuclear ribosomal internal and external transcribed spacer regions we detected seven naturally occurring hybrids among a sample of approximately 125 individuals. Hybrids were characterized by morphologies that most closely resembled their maternal parents based on chloroplast evidence. Studies of artificially synthesized and natural hybrids demonstrated that hybrid seed had very low germination rates and naturally occurring hybrids exhibited pollen sterility. Post-zygotic reproductive isolating mechanisms play a primary role in limiting gene exchange between co-occurring species and maintaining species integrity in areas of sympatry. [ABSTRACT FROM AUTHOR]

Abstract: Strawberry plant tissues and particularly fruit material are rich in polysaccharides and polyphenolic compounds, thus rendering the isolation of nucleic acids a difficult task. This work describes the successful modification of a total RNA extraction protocol, which enables the isolation of high quantity and quality of total RNA from small amounts of strawberry leaf, root and fruit tissues. Reverse-transcription polymerase chain reaction (RT-PCR) amplification of GAPDH housekeeping gene from isolated RNA further supports the proposed protocol efficiency and its use for downstream molecular applications. This novel procedure was also successfully followed using other fruit tissues, such as olive and kiwifruit. In addition, optional treatment with RNase A following initial nucleic acid extraction can provide sufficient quality and quality of genomic DNA for subsequent PCR analyses, as evidenced from PCR amplification of housekeeping genes using extracted genomic DNA as template. Overall, this optimized protocol allows easy, rapid and economic isolation of high quality RNA from small amounts of an important fruit crop, such as strawberry, with extended applicability to other recalcitrant fruit crops. [Copyright &y& Elsevier]