Cross-talk interactions of exogenous nitric oxide and sucrose modulates phenylpropanoid metabolism in yellow lupine embryo axes infected with Fusarium oxysporum

AbstractThe aim of the study was to examine cross-talk of exogenous nitric oxide (NO) and sucrose in the mechanisms of synthesis and accumulation of isoflavonoids in embryo axes of Lupinus luteus L. cv. Juno. It was verified whether the interaction of these molecules can modulate the defense response of axes to infection and development of the pathogenic fungus Fusarium oxysporum f. sp. lupini. Sucrose alone strongly stimulated a high level of genistein glucoside in axes pretreated with exogenous nitric oxide (SNP or GSNO) and non-pretreated axes. As a result of amplification of the signal coming from sucrose and GSNO, high isoflavonoids accumulation was observed (+Sn+GSNO). It needs to be stressed that infection in tissues pretreated with SNP/GSNO and cultured on the medium with sucrose (+Si+SNP/+Si+GSNO) very strongly enhances the accumulation of free isoflavone aglycones. In +Si+SNP axes phenylalanine ammonia-lyase activity was high up to 72h. As early as at 12h in +Si+SNP axes an increase was recorded in gene expression level of the specific isoflavonoid synthesis pathway. At 24h in +Si+SNP axes a very high total antioxidant capacity dependent on the pool of fast antioxidants was noted. Post-infection generation of semiquinone radicals was lower in axes with a high level of sucrose than with a deficit

Bacterial Communities from the Arsenic Mine in Złoty Stok, Sudety Mountains, Poland

Investigations of bacterial communities and characterization of mineralogy of the environment in the Złoty Stok As-Au deposit werecarried out. PXRD analysis revealed the presence of picropharmacolite as the most common secondary arsenic mineral in the mine. Total DNA was extracted from slime streams or slime biofilms samples to investigate the bacterial communities. PCR amplification of 16S rDNA was performed followed by subcloning of its products. Over 170 clones were analyzed by means of RFLP method. Eight group of clones representing different restriction patterns were identified. The nucleotide sequences of their inserts suggest that bacteria present in the mine environment belong to: Flavobacteria, Sphingobacteriia, Bacteroides, Proteobacteria, Mollicutes and Firmicutes. The metagenomic approach allows to demonstrate a higher diversity of microbiota than classical microbiological studies of cultivable isolates

Live in the community - biofilm formation

Wszystkie organizmy żywe podlegają wpływom innych organizmów wykazując różnego rodzaju zachowania społeczne. Mikroorganizmy nie są wyjątkiem. Komórki bakterii wolno żyjących (planktonicznych) są w stanie nie tylko wydzielać związki sygnałowe ale także mogą je odbierać. Proces komunikacji bakterii opierający się na tego typu sygnałach chemicznych jest szczególnie ważny w wielokomórkowych strukturach, jakie mogą tworzyć bakterie, czyli biofilmach. Takie społeczności bakteryjne są w stanie wzrastać w wielu środowiskach biotycznych jak i abiotycznych, niejednokrotnie w warunkach ekstremalnych. Proces komunikacji pomiędzy komórkami jest bardzo ważny, umożliwia nie tylko dzielenie się funkcjami fizjologiczno-metabolicznymi, ale również sprzyja ewolucji bakterii wskutek horyzontalnego transferu genów. Istotne jest poznanie nie tylko sposobu komunikacji pomiędzy mikroorganizmami, ale także warunków w jakich może zachodzić oraz procesów metabolicznych, którymi może ona sterować.All living organisms interact with each other and may exhibit cooperative behavior. Bacteria are not an exception. Free-living cells (planctonic cells) are able to communicate to each other by using specific types of chemical compounds. Such communication processes between bacterial cells are particularly important in multicellular structures, referred to as biofilms. Those structures are able to grow both in biotic and abiotic environments, in many cases even in very extreme conditions. The cell-communication processes are so important in bacterial biofilms for they provide sharing of physiological and metabolic functions between different species and thus stimulation of horizontal gene transfer that leads to bacterial evolution. Therefore, of importance is not only discovery and understanding of the communication system between microorganisms, but also of the conditions in which they may occur and influence cellular metabolic processes

Effects of Endogenous Signals and Fusarium oxysporum on the Mechanism Regulating Genistein Synthesis and Accumulation in Yellow Lupine and Their Impact on Plant Cell Cytoskeleton

The aim of the study was to examine cross-talk interactions of soluble sugars (sucrose, glucose and fructose) and infection caused by Fusarium oxysporum f.sp. lupini on the synthesis of genistein in embryo axes of Lupinus luteus L.cv. Juno. Genistein is a free aglycone, highly reactive and with the potential to inhibit fungal infection and development of plant diseases. As signal molecules, sugars strongly stimulated accumulation of isoflavones, including genistein, and the expression of the isoflavonoid biosynthetic genes. Infection significantly enhanced the synthesis of genistein and other isoflavone aglycones in cells of embryo axes of yellow lupine with high endogenous sugar levels. The activity of β-glucosidase, the enzyme that releases free aglycones from their glucoside bindings, was higher in the infected tissues than in the control ones. At the same time, a very strong generation of the superoxide anion radical was observed in tissues with high sugar contents already in the initial stage of infection. During later stages after inoculation, a strong generation of semiquinone radicals was observed, which level was relatively higher in tissues deficient in sugars than in those with high sugar levels. Observations of actin and tubulin cytoskeletons in cells of infected embryo axes cultured on the medium with sucrose, as well as the medium without sugar, showed significant differences in their organization

The Influence of Lead on Generation of Signalling Molecules and Accumulation of Flavonoids in Pea Seedlings in Response to Pea Aphid Infestation

The aim of this study was to investigate the effect of an abiotic factor, i.e., lead at various concentrations (low causing a hormesis effect and causing high toxicity effects), on the generation of signalling molecules in pea (Pisum sativum L. cv. Cysterski) seedlings and then during infestation by the pea aphid (Acyrthosiphon pisum Harris). The second objective was to verify whether the presence of lead in pea seedling organs and induction of signalling pathways dependent on the concentration of this metal trigger defense responses to A. pisum. Therefore, the profile of flavonoids and expression levels of genes encoding enzymes of the flavonoid biosynthesis pathway (phenylalanine ammonialyase and chalcone synthase) were determined. A significant accumulation of total salicylic acid (TSA) and abscisic acid (ABA) was recorded in the roots and leaves of pea seedlings growing on lead-supplemented medium and next during infestation by aphids. Increased generation of these phytohormones strongly enhanced the biosynthesis of flavonoids, including a phytoalexin, pisatin. This research provides insights into the cross-talk between the abiotic (lead) and biotic factor (aphid infestation) on the level of the generation of signalling molecules and their role in the induction of flavonoid biosynthesis

The Dynamics of the Defense Strategy of Pea Induced by Exogenous Nitric Oxide in Response to Aphid Infestation

The aim of this study was to investigate the effect of exogenous nitric oxide (NO), i.e., S-nitrosoglutathione (GSNO) and sodium nitroprusside (SNP), on the metabolic status of Pisum sativum L. cv. Cysterski leaves infested by Acyrthosiphon pisum Harris, population demographic parameters and A. pisum feeding activity. A reduction in the level of semiquinone radicals in pea seedling leaves pretreated with exogenous NO occurred 24 h after A. pisum infestation, which was earlier than in non-pretreated leaves. A decrease in the level of O2•− was observed in leaves pretreated with GSNO and infested by aphids at 48 and 72 h post-infestation (hpi). Directly after the pretreatment with GSNO, an increase in the level of metal ions was recorded. NO considerably induced the relative mRNA levels for phenylalanine ammonia-lyase in 24-h leaves pretreated with NO donors, both non-infested and infested. NO stimulated the accumulation of pisatin in leaves until 24 h. The Electrical Penetration Graph revealed a reduction in the feeding activity of the pea aphid on leaves pretreated with NO. The present study showed that foliar application of NO donors induced sequentially defense reactions of pea against A. pisum and had a deterrent effect on aphid feeding and limited the population growth rate