The interaction of jasmonic acid, sucrose and light is reflected in photosynthetic pigment metabolism in potatoes grown in vitro

We previously demonstrated that sucrose and jasmonic acid (JA) interact duringin photosynthetic in the regulation of development and pigment metabolism of the potato (Solanum tuberosum L cv. Sante) grown in vitro. In this study, the research was extended to the effect of light irradiance and quality on sucrose and JA mediated changes. Potato plantlets grown from stem node culture were grown on a medium supplemented with 30 mM or 90 mM sucrose and 0.1, 1, or 10 μM JA at 55-70 μmol m-2 s-1 (Osram Cool White lights) or at 80-100 μmol m-2 s-1 (Osram Fluora lights). Higher amounts of chlorophyll were detected in plants grown at lower irradiance while there was no significant difference in carotenoid levels. Sucrose and JA both enhanced root growth and inhibited photosynthetic pigment accumulation. Most effective was 1 μM JA at higher sucrose concentrations. In these growth conditions the plantlets were hyperhydric and had the most developed root system. The present study demonstrates that the growth of plants in vitro and the photosynthetic pigment metabolism are highly dependent on the interaction of a number of environmental factors such as sucrose and plant growth regulators in the medium, and light irradiance and quality. This result supports our previous findings that the reduction of photosynthetic pigment accumulation in cv. Sante potato plantlets induced by JA could be mainly the consequence of enhanced import of sucrose from the medium

The development of new methods for monitoring biocontrol agent, Gliocladium catenulatum J1446, to control gray mold on strawberries

Gray mold, caused by the fungus Botrytis cinerea, is one of the most common and serious diseases affecting strawberries. Different fungicides are used to manage this disease but can quickly lose their effectiveness and their ability to suppress the disease. Therefore, much attention is devoted to biological methods of control in recent years. Preparation PrestopMIX (Verdera Oy, Finland) is available in some European countries. It contains a biocontrol agent (BCA), isolate J1446 of the fungus Gliocladium catenulatum, active against grey mold. In the project Bicopoll, a project of European transnational research cooperation project CORE Organic II, we are checking for residues of BSA in bee products (honey, pollen) and following BCA distribution to strawberry flowers by bees. For this purpose, we developed a new, BCA specific real time PCR, which allows us to detect BCA in different samples and quantify it. Development of a new method and its application will be presented

'Bois noir' phytoplasma induces significant reprogramming of the leaf transcriptome in the field grown grapevine

<p>Abstract</p> <p>Background</p> <p>Phytoplasmas are bacteria without cell walls from the class <it>Mollicutes</it>. They are obligate intracellular plant pathogens which cause diseases in hundreds of economically important plants including the grapevine (<it>Vitis vinifera</it>). Knowledge of their biology and the mechanisms of their interactions with hosts is largely unknown because they are uncultivable and experimentally inaccessible in their hosts. We detail here the global transcriptional profiling in grapevine responses to phytoplasmas. The gene expression patterns were followed in leaf midribs of grapevine cv. 'Chardonnay' naturally infected with a phytoplasma from the stolbur group 16SrXII-A, which is associated with the grapevine yellows disease 'Bois noir'.</p> <p>Results</p> <p>We established an on field experimental system in a productive vineyard that allowed application of molecular tools in a plant natural environment. Global transcription profiles of infected samples were compared with the healthy ones using microarray datasets and metabolic pathway analysis software (MapMan). The two-year-long experiment revealed that plant genes involved in primary and secondary metabolic pathways were changed in response to infection and that these changes might support phytoplasma nutrition. A hypothesis that phytoplasmas interact with the plant carbohydrate metabolism was proven and some possibilities how the products of this pathway might be utilized by phytoplasmas are discussed. In addition, several photosynthetic genes were largely down-regulated in infected plants, whereas defense genes from the metabolic pathway leading to formation of flavonoids and some PR proteins were significantly induced. Few other genes involved in defense-signaling were differentially expressed in healthy and infected plants. A set of 17 selected genes from several differentially expressed pathways was additionally analyzed with quantitative real-time PCR and confirmed to be suitable for a reliable classification of infected plants and for the characterization of susceptibility features in the field conditions.</p> <p>Conclusion</p> <p>This study revealed some fundamental aspects of grapevine interactions with the stolbur 'Bois noir' phytoplasma in particular and some plant interactions with phytoplasmas in general. In addition, the results of the study will likely have an impact on grape improvement by yielding marker genes that can be used in new diagnostic assays for phytoplasmas or by identifying candidate genes that contribute to the improved properties of grape.</p

Newly Isolated Bacteriophages from the Podoviridae, Siphoviridae, and Myoviridae Families Have Variable Effects on Putative Novel Dickeya spp.

Soft rot pathogenic bacteria from the genus Dickeya cause severe economic losses in orchid nurseries worldwide, and there is no effective control currently available. In the last decade, the genus Dickeya has undergone multiple changes as multiple new taxa have been described, and just recently a new putative Dickeya species was reported. This study reports the isolation of three bacteriophages active against putative novel Dickeya spp. isolates from commercially produced infected orchids that show variable host-range profiles. Bacteriophages were isolated through enrichment from Dickeya-infected orchid tissue. Convective interaction media monolith chromatography was used to isolate bacteriophages from wastewaters, demonstrating its suitability for the isolation of infective bacteriophages from natural sources. Based on bacteriophage morphology, all isolated bacteriophages were classified as being in the order Caudovirales, belonging to three different families, Podoviridae, Myoviridae, and Siphoviridae. The presence of three different groups of bacteriophages was confirmed by analyzing the bacteriophage specificity of bacterial hosts, restriction fragment length polymorphism and plaque morphology. Bacteriophage BF25/12, the first reported Podoviridae bacteriophage effective against Dickeya spp., was selected for further characterization. Its genome sequence determined by next-generation sequencing showed limited similarity to other characterized Podoviridae bacteriophages. Interactions among the bacteriophages and Dickeya spp. were examined using transmission electron microscopy, which revealed degradation of electron-dense granules in response to bacteriophage infection in some Dickeya strains. The temperature stability of the chosen Podoviridae bacteriophage monitored over 1 year showed a substantial decrease in the survival of bacteriophages stored at -20°C over longer periods. It showed susceptibility to low pH and UV radiation but was stable in neutral and alkaline pH. Furthermore, the stability of the tested bacteriophage was also connected to the incubation medium and bacteriophage concentration at certain pH values. Finally, the emergence of bacteriophage-resistant bacterial colonies is highly connected to the concentration of bacteriophages in the bacterial environment. This is the first report on bacteriophages against Dickeya from the Podoviridae family to expand on potential bacteriophages to include in bacteriophage cocktails as biocontrol agents. Some of these bacteriophage isolates also showed activity against Dickeya solani, an aggressive strain that causes the soft rot of potatoes, which indicates their broad potential as biocontrol agents

Revealing fosfomycin primary effect on Staphylococcus aureus transcriptome: modulation of cell envelope biosynthesis and phosphoenolpyruvate induced starvation

<p>Abstract</p> <p>Background</p> <p><it>Staphylococcus aureus </it>is a highly adaptable human pathogen and there is a constant search for effective antibiotics. Fosfomycin is a potent irreversible inhibitor of MurA, an enolpyruvyl transferase that uses phosphoenolpyruvate as substrate. The goal of this study was to identify the pathways and processes primarily affected by fosfomycin at the genome-wide transcriptome level to aid development of new drugs.</p> <p>Results</p> <p><it>S. aureus </it>ATCC 29213 cells were treated with sub-MIC concentrations of fosfomycin and harvested at 10, 20 and 40 minutes after treatment. <it>S. aureus </it>GeneChip statistical data analysis was complemented by gene set enrichment analysis. A visualization tool for mapping gene expression data into biological pathways was developed in order to identify the metabolic processes affected by fosfomycin. We have shown that the number of significantly differentially expressed genes in treated cultures increased with time and with increasing fosfomycin concentration. The target pathway - peptidoglycan biosynthesis - was upregulated following fosfomycin treatment. Modulation of transport processes, cofactor biosynthesis, energy metabolism and nucleic acid biosynthesis was also observed.</p> <p>Conclusions</p> <p>Several pathways and genes downregulated by fosfomycin have been identified, in contrast to previously described cell wall active antibiotics, and was explained by starvation response induced by phosphoenolpyruvate accumulation. Transcriptomic profiling, in combination with meta-analysis, has been shown to be a valuable tool in determining bacterial response to a specific antibiotic.</p

Enhanced detection of pathogenic enteric viruses in coastal marine environment by concentration using methacrylate monolithic chromatographic supports paired with quantitative PCR

AbstractCurrently, around 50% of the world's population lives in towns and cities within 100 km of the coast. Monitoring of viruses that are frequently present in contaminated coastal environments, such as rotavirus (RoV) and norovirus (NoV), which are also the major cause of human viral gastroenteritis, is essential to ensure the safe use of these water bodies. Since exposure to as few as 10–100 particles of RoV or NoV may induce gastrointestinal disease, there is a need to develop a rapid and sensitive diagnostic method for their detection in coastal water samples. In this study, we evaluate the application of methacrylate monolithic chromatographic columns, commercially available as convective interaction media (CIM®), to concentrate pathogenic enteric viruses from saline water samples prior to virus quantification by one-step reverse transcription quantitative PCR (RT-qPCR). Using RoV and NoV as model enteric viruses, we present our results on the most effective viral concentration conditions from saline water matrices using butyl (C4) hydrophobic interaction monolithic support (CIM® C4). C4 monolithic columns exhibit a good capacity to bind both RoV and NoV and both viruses can be eluted in a single step. Our protocol using a 1 ml C4 column enables processing of 400 ml saline water samples in less than 60 min and increases the sensitivity of RoV and NoV detection by approximately 50-fold and 10-fold respectively. The protocol was also scaled up using larger capacity 8 ml C4 columns to process 4000 ml of seawater samples with concentration factors of 300-fold for RoV and 40-fold for NoV, without any significant increase in processing time. Furthermore, C4 monolithic columns were adapted for field use in an on-site application of RoV concentration from seawater samples with performance equivalent to that of the reference laboratory setup. Overall, the results from successful deployment of CIM C4 columns for concentration of rotavirus and norovirus in seawater samples reiterate the utility of monolithic supports as efficient, scalable and modular preparative tools for processing environmental water samples to enhance viral detection using molecular methods

Global Advances in Tomato Virome Research: Current Status and the Impact of High-Throughput Sequencing

Viruses cause a big fraction of economically important diseases in major crops, including tomato. In the past decade (2011–2020), many emerging or re-emerging tomato-infecting viruses were reported worldwide. In this period, 45 novel viral species were identified in tomato, 14 of which were discovered using high-throughput sequencing (HTS). In this review, we first discuss the role of HTS in these discoveries and its general impact on tomato virome research. We observed that the rate of tomato virus discovery is accelerating in the past few years due to the use of HTS. However, the extent of the post-discovery characterization of viruses is lagging behind and is greater for economically devastating viruses, such as the recently emerged tomato brown rugose fruit virus. Moreover, many known viruses still cause significant economic damages to tomato production. The review of databases and literature revealed at least 312 virus, satellite virus, or viroid species (in 22 families and 39 genera) associated with tomato, which is likely the highest number recorded for any plant. Among those, here, we summarize the current knowledge on the biology, global distribution, and epidemiology of the most important species. Increasing knowledge on tomato virome and employment of HTS to also study viromes of surrounding wild plants and environmental samples are bringing new insights into the understanding of epidemiology and ecology of tomato-infecting viruses and can, in the future, facilitate virus disease forecasting and prevention of virus disease outbreaks in tomato

HIGH INFECTION PRESSURE OF ESFY PHYTOPLASMA THREATENS THE CULTIVATION OF STONE FRUIT SPECIES

European stone fruit yellows fi toplazma (ESFY; ‘Candidatus Phytoplasma prunorum’) povzroča pri koščičastih sadnih vrstah nevarno bolezen leptonekrozo koščičarjev. ESFY fi toplazma se na gostiteljske rastline iz roda Prunus prenaša z vektorjem češpljevo bolšico (Cacopsylla pruni), kakor tudi z vegetativnim razmnoževanjem. V nasadu koščičastih sadnih vrst, posajenem leta 2001 z brezvirusnim matičnim materialom, je bilo v letih 2004 – 2006 spremljano stanje glede okuženosti z ESFY fi toplazmo ter skupno odvzetih 158 vzorcev. Pri vseh sadnih vrstah so bila vzorčena tako simptomatična, kot asimptomatična drevesa. Od 15.7 % vzorčenih dreves marelic (Prunus armeniaca) v nasadu, je bila prisotnost fi toplazem potrjena pri 70.0 % vzorčenih drevesih. Pri slivah kitajsko- japonskega izvora (Prunus salicina) je bilo vzorčenje opravljeno pri tretjini matičnih rastlin, prisotnost ESFY fi toplazme je bila dokazana pri vseh vzorčenih rastlinah. Pri evropski slivi (Prunus domestica) je bila okuženost s fi toplazmami potrjena pri 51.0 % vzorčenih rastlin, pri čemer rastline večinoma niso kazale vidnih bolezenskih znamenj. Prisotnost ESFY fi toplazme je bila potrjena tudi pri 13.0 % vzorčenih drevesih breskve (Prunus persica). Pri češnji (Prunus avium) prisotnost fi toplazme ESFY ni bila potrjena. ESFY fi toplazma je bila v letu 2005 z laboratorijskim testiranjem potrjena tudi v vseh analiziranih vzorcih prenašalca Cacopsylla pruni.Stone fruit species are affected by severe disease caused by European stone fruit yellows phytoplasma (ESFY; ‘Candidatus Phytoplasma prunorum’). ESFY phytoplasma is transmitted to the host plants of Prunus spp. by the vector Cacopsylla pruni. The disease is graft-transmissible as well. The occurence of ESFY phytoplasma was monitored from 2004 to 2006 in a mother plant orchard of stone fruit species planted with virus free material in 2001 in the Primorska region of Slovenia. The total of 158 samples of mother plants were analysed in this period. The symptomatic and asymptomatic trees were analysed using molecular methods (PCR or nested-PCR). Among 15.7 % of sampled apricot trees (Prunus armeniaca) in the orchard, ESFY phytoplasma was detected in 70.0 % of samples. In the case of Japanese plum (Prunus salicina) samples were taken from one third of all Japanese plum trees and the presence of ESFY phytoplasma was confi rmed in all samples. In the European plum trees (Prunus domestica) the incidence of phytoplasma was determined in 51.0 % of sampled trees, where the plants in most cases did not show symptoms. ESFY phytoplasma was also detected in peaches and nectarines (Prunus persica) in 13.0 % of sampled trees while no detection of the phytoplasma was confi rmed in the samples of cherry trees (Prunus avium). With the survey performed in a mother plant orchard it was observed that especially young trees did not show typical symptoms and the infection was latent. In the year 2005, ESFY phytoplasma was detected in all tested samples of the vector Cacopsylla pruni captured in the vicinity of the mother plant orchard

HIGH INFECTION PRESSURE OF ESFY PHYTOPLASMA THREATENS THE CULTIVATION OF STONE FRUIT SPECIES

European stone fruit yellows fi toplazma (ESFY; ‘Candidatus Phytoplasma prunorum’) povzroča pri koščičastih sadnih vrstah nevarno bolezen leptonekrozo koščičarjev. ESFY fi toplazma se na gostiteljske rastline iz roda Prunus prenaša z vektorjem češpljevo bolšico (Cacopsylla pruni), kakor tudi z vegetativnim razmnoževanjem. V nasadu koščičastih sadnih vrst, posajenem leta 2001 z brezvirusnim matičnim materialom, je bilo v letih 2004 – 2006 spremljano stanje glede okuženosti z ESFY fi toplazmo ter skupno odvzetih 158 vzorcev. Pri vseh sadnih vrstah so bila vzorčena tako simptomatična, kot asimptomatična drevesa. Od 15.7 % vzorčenih dreves marelic (Prunus armeniaca) v nasadu, je bila prisotnost fi toplazem potrjena pri 70.0 % vzorčenih drevesih. Pri slivah kitajsko- japonskega izvora (Prunus salicina) je bilo vzorčenje opravljeno pri tretjini matičnih rastlin, prisotnost ESFY fi toplazme je bila dokazana pri vseh vzorčenih rastlinah. Pri evropski slivi (Prunus domestica) je bila okuženost s fi toplazmami potrjena pri 51.0 % vzorčenih rastlin, pri čemer rastline večinoma niso kazale vidnih bolezenskih znamenj. Prisotnost ESFY fi toplazme je bila potrjena tudi pri 13.0 % vzorčenih drevesih breskve (Prunus persica). Pri češnji (Prunus avium) prisotnost fi toplazme ESFY ni bila potrjena. ESFY fi toplazma je bila v letu 2005 z laboratorijskim testiranjem potrjena tudi v vseh analiziranih vzorcih prenašalca Cacopsylla pruni.Stone fruit species are affected by severe disease caused by European stone fruit yellows phytoplasma (ESFY; ‘Candidatus Phytoplasma prunorum’). ESFY phytoplasma is transmitted to the host plants of Prunus spp. by the vector Cacopsylla pruni. The disease is graft-transmissible as well. The occurence of ESFY phytoplasma was monitored from 2004 to 2006 in a mother plant orchard of stone fruit species planted with virus free material in 2001 in the Primorska region of Slovenia. The total of 158 samples of mother plants were analysed in this period. The symptomatic and asymptomatic trees were analysed using molecular methods (PCR or nested-PCR). Among 15.7 % of sampled apricot trees (Prunus armeniaca) in the orchard, ESFY phytoplasma was detected in 70.0 % of samples. In the case of Japanese plum (Prunus salicina) samples were taken from one third of all Japanese plum trees and the presence of ESFY phytoplasma was confi rmed in all samples. In the European plum trees (Prunus domestica) the incidence of phytoplasma was determined in 51.0 % of sampled trees, where the plants in most cases did not show symptoms. ESFY phytoplasma was also detected in peaches and nectarines (Prunus persica) in 13.0 % of sampled trees while no detection of the phytoplasma was confi rmed in the samples of cherry trees (Prunus avium). With the survey performed in a mother plant orchard it was observed that especially young trees did not show typical symptoms and the infection was latent. In the year 2005, ESFY phytoplasma was detected in all tested samples of the vector Cacopsylla pruni captured in the vicinity of the mother plant orchard