Plasmodiophora brassicae, a soil-borne biotroph, establishes galls as strong physiological sinks on Brassicaceae plants including Brassica napus and Arabidopsis thaliana. We compare transcriptional profiles of phloem dissected from leaf petioles and hypocotyls of healthy and infected B. napus plants. Our results highlight how pathogenesis accompanies phloem-mediated defence responses whilst exerting a strong influence on carbon-nitrogen (C-N) economy. We observe transcriptional changes indicating decreased aliphatic glucosinolate biosynthesis, fluctuating jasmonic acid responses, altered amino acid (AA) and nitrate transport, carbohydrate metabolism and modified cytokinin responses. Changes observed in phloem-dissected from upper versus lower plant organs point to phloem as a conduit in mediating C-N repartitioning, nutrition-related signalling and cytokinin dynamics over long distances during clubroot disease. To assess changes in physiology, we measured AAs, sugars and cytokinins, in phloem exudates from B. napus plants. Despite the decrease in most AA and sucrose levels, isopentyl-type cytokinins increased within infected plants. Furthermore, we employed Arabidopsis for visualising promoter activities of B. napus AA and N transporter orthologues and tested the impact of disrupted cytokinin transport during P. brassicae-induced gall formation using Atabcg14 mutants. Our physiological and microscopy studies show that the host developmental reaction to P. brassicae relies on cytokinin and is accompanied by intense nitrogen and carbon repartitioning. Overall, our work highlights the systemic aspects of host responses that should be taken into account when studying clubroot disease.

• Klíčová slova
• Brassica napus, Plasmodiophora brassicae, clubroot, laser dissection transcriptomics, oilseed rape, phloem,
• MeSH
• aminokyseliny metabolismus   MeSH
• Arabidopsis * genetika   fyziologie   MeSH
• Brassica napus * genetika   metabolismus   fyziologie   parazitologie   MeSH
• cyklopentany metabolismus   MeSH
• cytokininy metabolismus   MeSH
• dusík metabolismus   MeSH
• floém * metabolismus   genetika   MeSH
• glukosinoláty metabolismus   MeSH
• listy rostlin genetika   metabolismus   MeSH
• nemoci rostlin * parazitologie   genetika   MeSH
• oxylipiny metabolismus   MeSH
• Plasmodiophorida * fyziologie   MeSH
• regulace genové exprese u rostlin * MeSH
• transkriptom MeSH
• uhlík metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• aminokyseliny MeSH
• cyklopentany MeSH
• cytokininy MeSH
• dusík MeSH
• glukosinoláty MeSH
• jasmonic acid MeSH Prohlížeč
• oxylipiny MeSH
• uhlík MeSH

Heterotrophic nanoflagellates (HNF) are considered as major planktonic bacterivores, however, larger HNF taxa can also be important predators of eukaryotes. To examine this trophic cascading, natural protistan communities from a freshwater reservoir were released from grazing pressure by zooplankton via filtration through 10- and 5-µm filters, yielding microbial food webs of different complexity. Protistan growth was stimulated by amendments of five Limnohabitans strains, thus yielding five prey-specific treatments distinctly modulating protistan communities in 10- versus 5-µm fractions. HNF dynamics was tracked by applying five eukaryotic fluorescence in situ hybridization probes covering 55-90% of total flagellates. During the first experimental part, mainly small bacterivorous Cryptophyceae prevailed, with significantly higher abundances in 5-µm treatments. Larger predatory flagellates affiliating with Katablepharidacea and one Cercozoan lineage (increasing to up to 28% of total HNF) proliferated towards the experimental endpoint, having obviously small phagocytized HNF in their food vacuoles. These predatory flagellates reached higher abundances in 10-µm treatments, where small ciliate predators and flagellate hunters also (Urotricha spp., Balanion planctonicum) dominated the ciliate assemblage. Overall, our study reports pronounced cascading effects from bacteria to bacterivorous HNF, predatory HNF and ciliates in highly treatment-specific fashions, defined by both prey-food characteristics and feeding modes of predominating protists.

• Klíčová slova
• Cercozoa, Cryptophyceae, Katablepharidacea, bacterivorous and predatory flagellates, ciliates, freshwater microbial food webs,
• MeSH
• Cercozoa * MeSH
• Cryptophyta MeSH
• hybridizace in situ fluorescenční MeSH
• potravní řetězec * MeSH
• sladká voda MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Plants as non-mobile organisms constantly integrate varying environmental signals to flexibly adapt their growth and development. Local fluctuations in water and nutrient availability, sudden changes in temperature or other abiotic and biotic stresses can trigger changes in the growth of plant organs. Multiple mutually interconnected hormonal signaling cascades act as essential endogenous translators of these exogenous signals in the adaptive responses of plants. Although the molecular backbones of hormone transduction pathways have been identified, the mechanisms underlying their interactions are largely unknown. Here, using genome wide transcriptome profiling we identify an auxin and cytokinin cross-talk component; SYNERGISTIC ON AUXIN AND CYTOKININ 1 (SYAC1), whose expression in roots is strictly dependent on both of these hormonal pathways. We show that SYAC1 is a regulator of secretory pathway, whose enhanced activity interferes with deposition of cell wall components and can fine-tune organ growth and sensitivity to soil pathogens.

• MeSH
• Arabidopsis genetika   růst a vývoj   metabolismus   MeSH
• buněčná stěna chemie   metabolismus   MeSH
• cytokininy metabolismus   MeSH
• endozomy metabolismus   MeSH
• geneticky modifikované rostliny metabolismus   MeSH
• Golgiho aparát metabolismus   MeSH
• kořeny rostlin metabolismus   mikrobiologie   MeSH
• kyseliny indoloctové metabolismus   MeSH
• membránové proteiny genetika   metabolismus   MeSH
• odolnost vůči nemocem genetika   MeSH
• Plasmodiophorida patogenita   MeSH
• proteiny huseníčku genetika   metabolismus   MeSH
• půda MeSH
• regulace genové exprese u rostlin genetika   MeSH
• regulátory růstu rostlin metabolismus   MeSH
• sekreční dráha genetika   MeSH
• stanovení celkové genové exprese MeSH
• transkriptom genetika   MeSH
• vezikulární transportní proteiny metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• AT2G18840 protein, Arabidopsis MeSH Prohlížeč
• AT4G30260 protein, Arabidopsis MeSH Prohlížeč
• cytokininy MeSH
• ECHIDNA protein, Arabidopsis MeSH Prohlížeč
• kyseliny indoloctové MeSH
• membránové proteiny MeSH
• proteiny huseníčku MeSH
• půda MeSH
• regulátory růstu rostlin MeSH
• SYAC1 protein, Arabidopsis MeSH Prohlížeč
• vezikulární transportní proteiny MeSH

Marine phytomyxids represent often overlooked obligate biotrophic parasites colonizing diatoms, brown algae, and seagrasses. An illustrative example of their enigmatic nature is the phytomyxid infecting the seagrass Halophila stipulacea (a well-known Lessepsian migrant from the Indo-Pacific to the Mediterranean Sea). In the Mediterranean, the occurrence of this phytomyxid was first described in 1995 in the Strait of Messina (southern Italy) and the second time in 2017 in the Aegean coast of Turkey. Here we investigated, using scuba diving, stereomicroscopy, light and scanning electron microscopy, and molecular methods, whether the symbiosis is still present in southern Italy, its distribution in this region and its relation to the previous reports. From the total of 16 localities investigated, the symbiosis has only been found at one site. A seasonal pattern was observed with exceptionally high abundance (> 40% of the leaf petioles colonized) in September 2017, absence of the symbiosis in May/June 2018, and then again high infection rates (~ 30%) in September 2018. In terms of anatomy and morphology as well as resting spore dimensions and arrangement, the symbiosis seems to be identical to the preceding observations in the Mediterranean. According to the phylogenetic analyses of the 18S rRNA gene, the phytomyxid represents the first characterized member of the environmental clade "TAGIRI-5". Our results provide new clues about its on-site ecology (incl. possible dispersal mechanisms), hint that it is rare but established in the Mediterranean, and encourage further research into its distribution, ecophysiology, and taxonomy.

• Klíčová slova
• Invasive seagrass, Plasmodiophora, Plasmodiophorids, Seagrass disease, Seagrass symbionts, Tetramyxa,
• MeSH
• Cercozoa klasifikace   genetika   fyziologie   MeSH
• fylogeneze MeSH
• Hydrocharitaceae parazitologie   MeSH
• listy rostlin parazitologie   MeSH
• RNA protozoální analýza   MeSH
• RNA ribozomální 18S analýza   MeSH
• symbióza * MeSH
• zavlečené druhy MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Itálie MeSH
• Středozemní moře MeSH
• Názvy látek
• RNA protozoální MeSH
• RNA ribozomální 18S MeSH

Hormonal dynamics after Plasmodiophora brassicae infection were compared in two Brassica napus cultivars-more resistant SY Alister and more sensitive Hornet, in order to elucidate responses associated with efficient defense. Both cultivars responded to infection by the early transient elevation of active cytokinins (predominantly cis-zeatin) and auxin indole-3-acetic acid (IAA) in leaves and roots, which was longer in Hornet. Moderate IAA levels in Hornet roots coincided with a high expression of biosynthetic gene nitrilase NIT1 (contrary to TAA1, YUC8, YUC9). Alister had a higher basal level of salicylic acid (SA), and it stimulated its production (via the expression of isochorismate synthase (ICS1)) in roots earlier than Hornet. Gall formation stimulated cytokinin, auxin, and SA levels-with a maximum 22 days after inoculation (dai). SA marker gene PR1 expression was the most profound at the time point where gall formation began, in leaves, roots, and especially in galls. Jasmonic acid (JA) was higher in Hornet than in Alister during the whole experiment. To investigate SA and JA function, SA was applied before infection, and twice (before infection and 15 dai), and JA at 15 dai. Double SA application diminished gall formation in Alister, and JA promoted gall formation in both cultivars. Activation of SA/JA pathways reflects the main differences in clubroot resistance.

• Klíčová slova
• Brassica napus, Plasmodiophora brassicae, auxin, cytokinin, gene expression, jasmonic acid, plant hormone, resistance, salicylic acid,
• MeSH
• aminohydrolasy genetika   MeSH
• Brassica napus růst a vývoj   metabolismus   parazitologie   MeSH
• cyklopentany analýza   MeSH
• cytokininy analýza   MeSH
• intramolekulární transferasy genetika   MeSH
• kořeny rostlin růst a vývoj   metabolismus   parazitologie   MeSH
• kyseliny indoloctové analýza   MeSH
• listy rostlin růst a vývoj   metabolismus   parazitologie   MeSH
• nemoci rostlin parazitologie   MeSH
• odolnost vůči nemocem MeSH
• oxylipiny analýza   MeSH
• Plasmodiophorida patogenita   MeSH
• regulace genové exprese u rostlin MeSH
• regulátory růstu rostlin analýza   MeSH
• rostlinné proteiny genetika   MeSH
• vývojová regulace genové exprese MeSH
• Publikační typ
• časopisecké články MeSH
• srovnávací studie MeSH
• Názvy látek
• aminohydrolasy MeSH
• cyklopentany MeSH
• cytokininy MeSH
• intramolekulární transferasy MeSH
• isochorismate synthase MeSH Prohlížeč
• jasmonic acid MeSH Prohlížeč
• kyseliny indoloctové MeSH
• nitrilase MeSH Prohlížeč
• oxylipiny MeSH
• regulátory růstu rostlin MeSH
• rostlinné proteiny MeSH

Two amoeboid organisms of the genera Sappinia Dangeard, 1896 and Rosculus Hawes, 1963 were identified in a sample containing king penguin guano. This sample, collected in the Subantarctic, enlarges the list of fecal habitats known for the presence of coprophilic amoebae. The two organisms were co-isolated and subcultured for over 6 mo, with continuous efforts being invested to separate each one from the mixed culture. In the mixed culture, Rosculus cells were fast growing, tolerated changes in culturing conditions, formed cysts, and evidently were attracted by Sappinia trophozoites. The separation of the Rosculus strain was accomplished, whereas the Sappinia strain remained intermixed with inseparable Rosculus cells. Sappinia cell populations were sensitive to changes in culturing conditions; they improved with reduction of Rosculus cells in the mixed culture. Thick-walled cysts, reportedly formed by Sappinia species, were not seen. The ultrastructure of both organisms was congruent with the currently accepted generic characteristics; however, some details were remarkable at the species level. Combined with the results of phylogenetic analyses, our findings indicate that the ultrastructure of the glycocalyx and the presence/absence of the Golgi apparatus in differential diagnoses of Sappinia species require a critical re-evaluation.

• Klíčová slova
• Coprophilic amoebae, HGR clade, free-living amoebae, molecular phylogeny, polar region, ultrastructure,
• MeSH
• Amoebozoa klasifikace   genetika   izolace a purifikace   ultrastruktura   MeSH
• Cercozoa klasifikace   genetika   izolace a purifikace   ultrastruktura   MeSH
• ekosystém MeSH
• feces parazitologie   MeSH
• fylogeneze MeSH
• Spheniscidae parazitologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Georgia MeSH

Plasmodiophora brassicae is a soil-borne pathogen that belongs to Rhizaria, an almost unexplored eukaryotic organism group. This pathogen requires a living host for growth and multiplication, which makes molecular analysis further complicated. To broaden our understanding of a plasmodiophorid such as P. brassicae, we here chose to study immunophilins, a group of proteins known to have various cellular functions, including involvement in plant defense and pathogen virulence. Searches in the P. brassicae genome resulted in 20 putative immunophilins comprising of 11 cyclophilins (CYPs), 7 FK506-binding proteins (FKBPs) and 2 parvulin-like proteins. RNAseq data showed that immunophilins were differentially regulated in enriched life stages such as germinating spores, maturing spores, and plasmodia, and infected Brassica hosts (B. rapa, B. napus and B. oleracea). PbCYP3 was highly induced in all studied life stages and during infection of all three Brassica hosts, and hence was selected for further analysis. PbCYP3 was heterologously expressed in Magnaporthe oryzae gene-inactivated ΔCyp1 strain. The new strain ΔCyp1+ overexpressing PbCYP3 showed increased virulence on rice compared to the ΔCyp1 strain. These results suggest that the predicted immunophilins and particularly PbCYP3 are activated during plant infection. M. oryzae is a well-studied fungal pathogen and could be a valuable tool for future functional studies of P. brassicae genes, particularly elucidating their role during various infection phases.

• Klíčová slova
• Cyclophilin, Immunophilin, Plasmodiophora brassicae, Rhizaria,
• MeSH
• Brassica klasifikace   parazitologie   MeSH
• cyklofiliny klasifikace   genetika   metabolismus   MeSH
• fylogeneze MeSH
• imunofiliny genetika   metabolismus   MeSH
• interakce hostitele a patogenu MeSH
• kořeny rostlin parazitologie   MeSH
• nemoci rostlin parazitologie   MeSH
• Plasmodiophorida genetika   metabolismus   fyziologie   MeSH
• protozoální proteiny genetika   metabolismus   MeSH
• regulace genové exprese MeSH
• sekvence aminokyselin MeSH
• sekvenční homologie aminokyselin MeSH
• spory protozoální genetika   MeSH
• stanovení celkové genové exprese metody   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• cyklofiliny MeSH
• imunofiliny MeSH
• protozoální proteiny MeSH

Fungi, nematodes and oomycetes belong to the most prominent eukaryotic plant pathogenic organisms. Unicellular organisms from other eukaryotic lineages, commonly addressed as protists, also infect plants. This review provides an introduction to plant pathogenic protists, including algae infecting oomycetes, and their current state of research.

• Klíčová slova
• algae, phytomonas, phytomyxae, plant pathogens, plasmodiophorids, protist, stramenopiles,
• MeSH
• oomycety patogenita   MeSH
• Plasmodiophorida patogenita   MeSH
• rostliny mikrobiologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH

The case study targeted to determine the aetiology of nodular gill disease (NGD) of farmed rainbow trout. The methods included microscopical examination of gill material in fresh, culturing of isolated organisms, histology, transmission electron microscopy and molecular biology identification. The results revealed an intravital colonization of fish gills by the testate amoeba Rhogostoma minus Belar, 1921. Rhogostoma infection was found in all fish examined microscopically (15/15); in contrast, naked amoebae related to fully developed NGD lesions were found in minority of these fish (5/15). They belonged to four genera, Acanthamoeba, Vermamoeba, Naegleria and Vannella. Results presented in this study contribute to the mosaic of findings that contrary to amoebic gill disease of marine fish turn attention to the possibility of the heterogeneous, multi-amoeba-species and multifactorial aetiology of NGD.

• Klíčová slova
• Rhogostoma minus, naked amoebae, nodular gill disease, testate amoebae,
• MeSH
• amébiáza parazitologie   veterinární   MeSH
• Cercozoa klasifikace   izolace a purifikace   fyziologie   MeSH
• koinfekce MeSH
• nemoci ryb parazitologie   MeSH
• Oncorhynchus mykiss parazitologie   MeSH
• žábry parazitologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH