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  • Open access
  • 36 Reads
Phenolic Compounds as Biomarkers of Interactions between the Endophyte Klebsiella oxytoca and the Common Duckweed, Lemna minor L. Belgrade

The common duckweed (Lemna minor L.) is a cosmopolitan, miniature, fast-reproducing higher aquatic plant. In the last decade, the common duckweed as a model organism is experiencing a form of a renaissance: it is being re-discovered as an optimal model organism due to its simplified morphology, small genome, dominant vegetative reproduction, and minimal requirements for in vitro growth. One of the most striking characteristics of L. minor is its ability to co-exist with various microorganisms. Rhizosphere was recognized as a natural source of various beneficial microorganisms that can be utilized in different areas, e.g. agriculture and bioremediation. In this study, our focus was on the interactions between duckweeds and a rhizosphere-associated bacterial strain Klebsiella oxytoca (Access. No. MK212915). Our aim was to identify different phenolic compounds that might reflect complex interactions between the plant and this endophytic bacterium. Five distinct phenolic compounds were isolated by liquid chromatography - mass spectrometry: luteolin 6,8-di-C-hexoside, p-hydroxybenzoic acid, caffeic acid, apigenin 6-C-(2"-pentosyl)hexoside and p-coumaric acid. These compounds were apparently unique to this type of interaction between two distinct species. All of the identified compounds might reflect the invasion and colonization of the plant by K. oxytoca. Bibliographic analysis of key terms discovered that this area of research is vastly underrepresented in scientific literature. This paper is another call for all plant physiologists to focus their research on L. minor as a versatile model organism and to analyze different aspects of complex plant/bacterium interactions.

  • Open access
  • 22 Reads
Crop Wild Relatives (CWR) from Italy: Threatened Endemisms

The study presents an updated overview of the 28 endemic threatened Crop Wild Relatives (CWR) in Italy: Arrhenatherum elatius subsp. nebrodense, Barbarea rupicola, Brassica baldensis, Brassica glabrescens, Brassica macrocarpa, Brassica rupestris subsp. hispida, Brassica rupestris subsp. rupestris, Brassica trichocarpa, Brassica tyrrhena, Brassica villosa subsp. bivonana, Brassica villosa subsp. brevisiliqua, Brassica villosa subsp. drepanensis, Brassica villosa subsp. tineoi, Brassica villosa subsp. villosa, Daucus broteroi, Daucus carota subsp. rupestris, Daucus nebrodensis, Diplotaxis scaposa, Thinopyrum corsicum (=Elytrigia corsica), Festuca centroapenninica, Lathyrus apenninus, Lathyrus odoratus, Malus crescimmanoi, Phalaris arundinacea subsp. rotgesii, Vicia consentina, Vicia giacominiana, Vicia ochroleuca subsp. ochroleuca, Vicia tenuifolia subsp. elegans. Geographical distribution, ecology (with plant communities and habitat 92/43/EEC aspects), genetics (focused on gene pools), property, and in situ and ex situ conservation were analyzed. In addition, with the aim of their protection and valorization, specific actions are recommended.

  • Open access
  • 18 Reads
Genetic diversity of oat genotypes using SCoT markers

Oat (Avena L.) is an important animal feed and food crop. It belongs to alternative cereals, which can properly supplement traditional types of cereals. The goal of the study was to analyze the genetic variability of oat genotypes using SCoT technique, which uses gene specific primers. In the study, there were analyzed a total of 22 varieties of oats, of which 20 varieties were wild oats, and 2 of them were naked oats, that come from different European countries and Canada, using 7 SCoT markers. In total, 40 fragments were amplified of which 26 were polymorphic with an average number of 3.71 polymorphic fragments per genotype. Using SCoT8 marker the highest number of polymorphic fragments (5) was detected. The highest percentage of polymorphism revealed SCoT23 marker (80 %). The average percentage of polymorphism was 65.67 %. The value of polymorphic information content (PIC), which proves the ability of the marker to differentiate genotypes, ranged from 0.305 (SCoT12) to 0.674 (SCoT8) with an average value of 0.506. In the dendrogram constructed using hierarchical cluster analysis the genotypes of oats were divided into two main groups whereby these groups were divided into several subgroups. Based on analyses two genetically the closest genotypes, cultivar Alf (Germany) and Amursky utes (Russia), grouped in the subgroup Ia. Two naked oats (Avena nuda L.), Czech genotype Izak and Slovak genotype Hronec, grouped side by side in subcluster Ia. Used SCoT markers showed the ability to identify and differentiate genotypes of the common and naked oat.

  • Open access
  • 14 Reads
Determining the Response of Citrus Plants to Reduced Nitrogen Fertilization

It is well known that there is a greater demand for food due to a larger global population. To cope with this situation, the conventional agriculture uses various strategies, being the most important the use of nitrogen-based fertilizers. However, the inappropriate and excessive use of these fertilizers leads to the appearance of serious environmental problems such as the pollution of aquifers or the eutrophication of lakes and reservoirs.

In order to solve this problem, several studies have been conducted in various crops searching the optimization of the use of these fertilizers, in order to guarantee high crop yields in a sustainable way. In our work, we determine the optimal amount of nitrogen for the rootstock citrus crops (Citrus macrophylla) grown in controlled temperature and light conditions. The reduction to 50% of nitrogen content was studied through the analysis of several phenotypic (number of leaves, leaf area and fresh weight of roots) and biochemical parameters (total proteins and enzymatic activities of nitrogen-fixing enzymes such as nitrate reductase and nitrite reductase). Data obtained showed that there were no significant differences between plants grown under conditions of 100% of nitrogen content and plants grown with 50% of nitrogen content in all the analysed parameters, except that plants grown with 50% of nitrogen content showed less leaf area than plants grown with 100% of nitrogen content. This suggests that roots of C. macrophylla plants are able to develop, transport and assimilate nitrogen with half nitrogen fertilization.

  • Open access
  • 31 Reads
Changes in the Differentiation Program of Phloem Derivatives of Birch Cambium after Trunk Girdling

The processes of cambial activity and secondary xylem and phloem differentiation are completely dependent on the influx of photoassimates. Trunk girdling is a frequently used method for studying cambial growth under conditions of different assimilate supply. We girdled 20-year-old birch trees (Betula pendula Roth) and took samples 1 cm (AG1) and 35 cm above the girdle (AG35). Tissues of ungirdled trees served as control. A sharp increase in carbohydrates level (AG1) inhibited xylogenesis and stimulated phloemogenesis. A moderate increase (AG35) also stimulated phloemogenesis; however, xylogenesis continued. The activity of the APL gene encoding a phloem-specific transcription factor correlates with the active phloemogenesis, as it was 2.18 (AG1) and 3 (AG35) times higher than in control. The Suc gene encoding transmembrane sucrose transporter was up-regulated in the AG1 and AG35 zones by 2.24 and 2.51 times, respectively, compared with the control, which indicates an active sucrose loading into cells and correlates with the preferential differentiation of parenchyma. The activity of the PIN1 gene encoding the auxin transporter was highest in zone AG35 (2.1 times higher than in the control). In zone AG1, the PIN1 activity was 1.7 times lower than that of AG35, which corresponds to the impaired differentiation of the phloem sieve tubes. The data obtained can be useful for a better understanding of physiological processes and predicting changes in the forest productivity under conditions of a changing climate.

  • Open access
  • 20 Reads
Cardosin B PSI Transiently Expressed in Arabidopsis Lines with Alterations of ER Structure Is Secreted to the Extracellular Space in Cotyledon Cells

As the main transport route in eukaryotic cells the secretory pathway involves several membranous compartments including the Endoplasmic Reticulum (ER), the Golgi apparatus and Vacuoles. The ER is considered the hub of the secretory pathway, as newly synthesized proteins are distributed to other organelles from the ER. Another vital transport route is the endocytic pathway, which occurs at the plasma membrane and allows the recycling of membranes and membrane proteins. It has been suggested that secretory and endocytic routes may share intermediate compartments ER-related. Therefore, our main goal was to identify any cell compartment common to both routes, combining mutants with altered ER structure with the expression of known vacuolar markers. The Arabidopsis thaliana mutants nai GFP-h and leb-2 GFP-h, presenting alterations of the ER morphology, were selected from the NASC database. Leaf cells ultrastructure was characterized through Transmission Electron Microscopy revealing huge well-defined starch granules in chloroplasts of both seedling and mature leaves of leb-2. The mutated lines were transiently transformed with PSI-B fused with mCherry to analyze the vacuolar routes. Observation by Confocal Microscopy showed that PSI-B is secreted in nai GFP-h and, to a lesser extent, in leb-2 GFP-h. In a secretion assay the PSI-B was found in the extracellular protein content. Given that PSI-B mediates trafficking to the vacuole, it is intriguing to find it extracellularly in these mutant lines. Further observations are required to understand the effect of these mutations in protein vacuolar transport and implications on secretory and endocytic pathways.

  • Open access
  • 37 Reads
Identification and Marker Assisted Introgression of Blast Resistance Gene into the Parental Line of Rice Hybrid
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Rice (Oryza sativa L.) is one of the most important and widely consumed staple food crops in the world. This crop severely affected by fungal disease called rice blast disease caused by Magnaporthe oryzae (synonymous: Pyricularia oryzae) is most destructive diseases and often causes severe reduction of about 80% of rice yield under conducive conditions. One dominant (Piz) was introgressed into TNAU CMS 2B through marker assisted breeding. This study identified 20 gene introgressed individuals in the early segregated materials through foreground selection. The identified heterozygous individuals with the high yielding background forwarded to next breeding cycles to identify Piz gene in homozygous conditions, and thus could be used as a valuable genetic resource for future rice breeding programme.

  • Open access
  • 27 Reads
The Impact of Aphids’ Herbivory on the Expression of Subtilisin-Like Protease Gene in Maize (Zea mays L.) Seedlings

The study was aimed at evaluating the effect of the bird cherry-oat aphid (Rhopalosiphum padi L.) feeding on the expression of subtilisin-like protease gene (LOC100285183) in the maize (Zea mays L.) seedlings. The plant material included 14-day-old seedlings of two selected maize cultivars: Ambrozja and Tasty Sweet (relatively resistant and susceptible to the aphids, respectively). The maize plants were artificially infested with adult apterae females of R. padi (0, 30 and 60 aphids per plant) for 0, 3, 6, 24, 48, 72 and 96 h. Gene expression quantification was performed using the real-time qRT-PCR technique. The obtained results were normalized to the actin-2 gene, and the relative expression of the subtilisin-like protease gene was assessed by the comparative Ct (ΔΔCt) method. Overall, the aphid-relatively resistant (Ambrozja cv.) maize seedlings characterized with up to 2.5-fold higher upregulation of the examined gene compared with the aphid-susceptible (Tasty Sweet cv.) plants. In addition, the magnitude of the gene expression increases was dependent on the insect abundance and duration of infestation time. The performed survey unveiled the crucial involvement of subtilisin-like protease gene in perception of biotic stress signal linked to the bird cherry-oat aphids’ feeding in tissues of maize host plants.

  • Open access
  • 29 Reads
Metagenomics of Distant Hybrids in the Genus Ribes (Grossulariaceae)

The genus Ribes consists of several subgenera and approximately 150 species. Some authors divide the genus into two genera - currants and gooseberries. Within the genus, the level of hybridization is higher into gooseberries than in intersectional currants. Currant-gooseberry and intersectional hybrids were created artificially using polyploidy method. By morphological, palynomorphological, karyological and other characteristics, currant-gooseberry hybrids are contrasting. Tetraploid currant-gooseberry hybrids Josta and Kroma have pollen grains with an intermediate morphological type, and pollen of the triploid Dlinnokistnaya CGL is not typical for the family. We performed a comparative metagenomic analysis of these three hybrids of known origin and their parental forms (R. niveum, R. reclinatum, R. divaricatum and R. nigrum) in order to assess changes in their genomes for the ITS1 of 35S rRNA gene. Intragenomic polymorphism was studied by locus-specific NGS sequencing on the Illumina MiSeq platform using primers ITS-1P and ITS-2. It was shown that the ribotypes of the hybrids correspond to those of the parental forms. Ribotypes of unknown origin, highly homologous to other currants, were found. It has been shown that most of the pseudogenes are not conserved in hybrids. Comparative plant metagenomics is an informative method for studying hybridization and hybrids of unknown origin.

  • Open access
  • 29 Reads
Use of Native Geophytes of Ornamental Interest: The Case Study of Sternbergia lutea (L.) Ker. Gawl. Ex Spreng

This study presents the first results of a research aimed to test the potential use of Meditarranean geophyte wild genotypes, for ornamental purposes. This work is based on a previous research carried out in 2013 that consisted in a screening of native geophytes, whose bulbs were collected in highly natural contexts. The present work is about a pot trial on Stembergia lutea (L.) Ker. Gawl. Ex Spreng bulbs.

In particular, tests were carried out on a core of 204 samples of S. lutea, collected from uncultivated lands nearby of Irsina (Matera province, Southern Italy). The propagating material was split into 4 diameter classes: <20 mm, 20-25 mm, 25 -30 mm, and > 30 mm. The bulbs of each size class were subjected to 3 cutting methods: 1) deep cross incisions, 2) superficial cross incisions, 3) emptying of the walker; a non- excised bulb was taken as control . At the end of September 2014, bulbs were planted in 4.5 l pots at a density of 3 bulbs pot-1. Pots were arranged in completely randomised factorial design with 3 replicates of each combination of the 16 experimental theses (4 diameters x 4 cutting types). During the trial some phenological (emergence, anthesis, senescence) and morphological (number of leaves, leaf size, number of flowers, number of bulblets, number of capsules) parameters were evaluated.

Results for the different types of cutting were similar regardless the diameter class , deep cutting gave significantly lower values of most morphological parameters , except for the number of bulbets which was higher. Also a delay of senescence was measured. Noticeably, the walker emptying method yielded a higher number of flowers, and hence a larger number of capsules.

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