Background  In viticulture, iron (Fe) chlorosis is a common abiotic stress that impairs plant development and leads to yield and quality losses. Under low availability of the metal, the applied N form (nitrate and ammonium) can play a role in promoting or mitigating Fe deficiency stresses. However, the processes involved are not clear in grapevine. Therefore, the aim of this study was to investigate the response of two grapevine rootstocks to the interaction between N forms and Fe uptake. This process was evaluated in a hydroponic experiment using two ungrafted grapevine rootstocks Fercal (Vitis berlandieri x V. vinifera) tolerant to deficiency induced Fe chlorosis and Couderc 3309 (V. riparia x V. rupestris) susceptible to deficiency induced Fe chlorosis. Results  The results could differentiate Fe deficiency effects, N-forms effects, and rootstock effects. Interveinal chlorosis of young leaves appeared earlier on 3309 C from the second week of treatment with NO3−/NH4+ (1:0)/-Fe, while Fercal leaves showed less severe symptoms after four weeks of treatment, corresponding to decreased chlorophyll concentrations lowered by 75% in 3309 C and 57% in Fercal. Ferric chelate reductase (FCR) activity was by trend enhanced under Fe deficiency in Fercal with both N combinations, whereas 3309 C showed an increase in FCR activity under Fe deficiency only with NO3−/NH4+ (1:1) treatment. With the transcriptome analysis, Gene Ontology (GO) revealed multiple biological processes and molecular functions that were significantly regulated in grapevine rootstocks under Fe-deficient conditions, with more genes regulated in Fercal responses, especially when both forms of N were supplied. Furthermore, the expression of genes involved in the auxin and abscisic acid metabolic pathways was markedly increased by the equal supply of both forms of N under Fe deficiency conditions. In addition, changes in the expression of genes related to Fe uptake, regulation, and transport reflected the different responses of the two grapevine rootstocks to different N forms. Conclusions  Results show a clear contribution of N forms to the response of the two grapevine rootstocks under Fe deficiency, highlighting the importance of providing both N forms (nitrate and ammonium) in an appropriate ratio in order to ease the rootstock responses to Fe deficiency.

Background ‘Candidatus Phytoplasma mali’, the causal agent of apple proliferation disease, exerts influence on its host plant through various effector proteins, including SAP11CaPm which interacts with different TEOSINTE BRANCHED1/ CYCLOIDEA/ PROLIFERATING CELL FACTOR 1 and 2 (TCP) transcription factors. This study examines the transcriptional response of the plant upon early expression of SAP11CaPm. For that purpose, leaves of Nicotiana occidentalis H.-M. Wheeler were Agrobacterium-infiltrated to induce transient expression of SAP11CaPm and changes in the transcriptome were recorded until 5 days post infiltration.Results The RNA-seq analysis revealed that presence of SAP11CaPm in leaves leads to downregulation of genes involved in defense response and related to photosynthetic processes, while expression of genes involved in energy production was enhanced.Conclusions The results indicate that early SAP11CaPm expression might be important for the colonization of the host plant since phytoplasmas lack many metabolic genes and are thus dependent on metabolites from their host plant.

CP (cisplatin) and mesoporous silica SBA-15 (Santa Barbara amorphous 15) loaded with CP (→SBA-15|CP) were tested in vitro and in vivo against low metastatic mouse melanoma B16F1 cell line. SBA-15 only, as drug carrier, is found to be not active, while CP and SBA-15|CP revealed high cytotoxicity in lower μM range. The activity of SBA-15|CP was found similar to the activity of CP alone. Both CP and SBA-15|CP induced inhibition of cell proliferation (carboxyfluorescein succinimidyl ester - CFSE assay) along with G2/M arrest (4′,6-diamidino-2-phenylindole - DAPI assay). Apoptosis (Annexin V/ propidium iodide - PI assay), through caspase activation (apostat assay) and nitric oxide (NO) production (diacetate(4-amino-5-methylamino-2′,7′-difluorofluorescein-diacetat) - DAF FM assay), was identified as main mode of cell death. However, slight elevated autophagy (acridine orange - AO assay) was detected in treated B16F1 cells. CP and SBA-15|CP did not affect production of ROS (reactive oxygen species) in B16F1 cells. Both SBA-15|CP and CP induced in B16F1 G2 arrest and subsequent senescence. SBA-15|CP, but not CP, blocked the growth of melanoma in C57BL/6 mice. Moreover, hepato- and nephrotoxicity in SBA-15|CP treated animals were diminished in comparison to CP confirming multiply improved antitumor potential of immobilized CP. Outstandingly, SBA-15 boosted in vivo activity and diminished side effects of CP.

Two novel Co(II) fenamato complexes containing bathocuproine (bcp), namely [Co(bcp)(flu)2] (1) and [Co(bcp)(nif)2] (2) (flu = flufenamato, nif = niflumato) were synthesized and characterized by elemental analysis, single-crystal X-ray structure analysis as well as absorption and fluorescence spectroscopy. Investigation of their molecular structure revealed that both complexes are isostructural and form analogous complex molecules, with a Co(II) atom hexacoordinated by two nitrogen atoms of bcp and four oxygen atoms of two chelate bonded flu (1) and nif (2) ligands in a distorted octahedral arrangement. Surprisingly, the results of cytotoxicity experiments on four cancer cell lines (HeLa, HT-29, PC-3 and MCF-7) have revealed that despite similar structure of the complexes, the nif complex exhibits significantly higher activity, being the most effective against the PC-3 cell line (IC50 (MTT) = 6.11 ± 1.95 μM). Further studies performed on PC-3 cell line have shown that the mechanism of the cytotoxic action of nif complex (2) might involve activation of autophagic processes and apoptosis, while for its flu analogue (1) apoptosis was detected.

Two novel triphenyltin(IV) compounds, [Ph3SnL1] (L1 = 2-(5-(4-fluorobenzylidene)-2,4-dioxotetrahydrothiazole-3-yl)propanoate (1)) and [Ph3SnL2] (L2 = 2-(5-(5-methyl-2-furfurylidene)-2,4-dioxotetrahydrothiazole-3-yl)propanoate (2)) were synthesized and characterized by FT-IR, (1H and 13C) NMR spectroscopy, mass spectrometry, and elemental microanalysis. The in vitro anticancer activity of the synthesized organotin(IV) compounds was determined against four tumor cell lines: PC-3 (prostate), HT-29 (colon), MCF-7 (breast), and HepG2 (hepatic) using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-12 diphenyltetrazolium bromide) and CV (crystal violet) assays. The IC50 values are found to be in the range from 0.11 to 0.50 μM. Compound 1 exhibits the highest activity toward PC-3 cells (IC50 = 0.115 ± 0.009 μM; CV assay). The tin and platinum uptake in PC-3 cells showed a threefold lower uptake of tin in comparison to platinum (as cisplatin). Together with its higher activity this indicates a much higher cell inhibition potential of the tin compounds (calculated to ca. 50 to 100 times). Morphological analysis suggested that the compounds induce apoptosis in PC-3 cells, and flow cytometry analysis revealed that 1 and 2 induce autophagy as well as NO (nitric oxide) production.

BackgroundAdventitious roots (ARs) are often necessary for plant survival, and essential for successful micropropagation. In Arabidopsis thaliana dark-grown seedlings AR-formation occurs from the hypocotyl and is enhanced by application of indole-3-butyric acid (IBA) combined with kinetin (Kin). The same IBA + Kin-treatment induces AR-formation in thin cell layers (TCLs). Auxin is the main inducer of AR-formation and xylogenesis in numerous species and experimental systems. Xylogenesis is competitive to AR-formation in Arabidopsis hypocotyls and TCLs. Jasmonates (JAs) negatively affect AR-formation in de-etiolated Arabidopsis seedlings, but positively affect both AR-formation and xylogenesis in tobacco dark-grown IBA + Kin TCLs. In Arabidopsis the interplay between JAs and auxin in AR-formation vs xylogenesis needs investigation. In de-etiolated Arabidopsis seedlings, the Auxin Response Factors ARF6 and ARF8 positively regulate AR-formation and ARF17 negatively affects the process, but their role in xylogenesis is unknown. The cross-talk between auxin and ethylene (ET) is also important for AR-formation and xylogenesis, occurring through EIN3/EIL1 signalling pathway. EIN3/EIL1 is the direct link for JA and ET-signalling. The research investigated JA role on AR-formation and xylogenesis in Arabidopsis dark-grown seedlings and TCLs, and the relationship with ET and auxin. The JA-donor methyl-jasmonate (MeJA), and/or the ET precursor 1-aminocyclopropane-1-carboxylic acid were applied, and the response of mutants in JA-synthesis and -signalling, and ET-signalling investigated. Endogenous levels of auxin, JA and JA-related compounds, and ARF6, ARF8 and ARF17 expression were monitored.ResultsMeJA, at 0.01 μM, enhances AR-formation, when combined with IBA + Kin, and the response of the early-JA-biosynthesis mutant dde2–2 and the JA-signalling mutant coi1–16 confirmed this result. JA levels early change during TCL-culture, and JA/JA-Ile is immunolocalized in AR-tips and xylogenic cells. The high AR-response of the late JA-biosynthesis mutant opr3 suggests a positive action also of 12-oxophytodienoic acid on AR-formation. The crosstalk between JA and ET-signalling by EIN3/EIL1 is critical for AR-formation, and involves a competitive modulation of xylogenesis. Xylogenesis is enhanced by a MeJA concentration repressing AR-formation, and is positively related to ARF17 expression.ConclusionsThe JA concentration-dependent role on AR-formation and xylogenesis, and the interaction with ET opens the way to applications in the micropropagation of recalcitrant species.

SBA-15 (Santa Barbara Amorphous 15) mesoporous silica and its functionalized form (with 3-mercaptopropyltriethoxysilane) SBA-15~SH were used as carriers for [Ru(η6-p-cymene)Cl2{Ph2P(CH2)3SPh-κP}] complex, denoted as [Ru]. Prepared mesoporous silica nanomaterials were characterized by traditional methods. Materials without [Ru] complex did not show any cytotoxic activity against melanoma B16 and B16-F10 cell lines. On the contrary, materials containing [Ru] such as SBA-15|[Ru] and SBA-15~SH|[Ru], exhibited very high activity against tested tumor cell lines, moreover with similar inhibitory potential. According to the loaded amount of the [Ru] in SBA-15|[Ru] and SBA-15~SH|[Ru] the IC50 values are 1–2μM depending on the test used, thus in comparison to [Ru] alone the activity of nanomaterials containing [Ru] are elevated 3–6 times in vitro. However, the mechanism of apoptosis induction differs for these two mesoporous silica. Unlike reference [Ru] compound and SBA-15~SH|[Ru], SBA-15|[Ru] induces high caspase activation. Discrepancy in mechanism of drugs action at intracellular level points towards an influence of functionalization as well as availability of the drug. Moreover, both SBA-15|[Ru] and SBA-15~SH|[Ru] similarly to [Ru] are declining autophagy in B16 cell line.

Four novel gold(III) complexes of general formulae [AuCl2{(S,S)-R2eddl}]PF6 (R2eddl = O,O′-dialkyl-(S,S)-ethylenediamine-N,N′-di-2-(4-methyl)pentanoate, R = n-Pr, n-Bu, n-Pe, i-Bu; 1–4, respectively), were synthesized and characterized by elemental analysis, UV/Vis, IR, and NMR spectroscopy, as well as high resolution mass spectrometry. Density functional theory calculations pointed out that (R,R)-N,N′-configuration diastereoisomers were energetically the most favorable. Duo to high cytotoxic activity complex 3 was chosen for stability study in DMSO, no decomposition occurs within 24 h, and for the reaction with ascorbic acid in which was reduced immediately. Additionally, 3 interacts with bovine serum albumin (BSA) as proven by UV/Vis spectroscopy. In vitro antitumor activity was determined against human cervix adenocarcinoma (HeLa), human myelogenous leukemia (K562), and human melanoma (Fem-x) cancer cell lines, as well as against non-cancerous human embryonic lung fibroblast cells MRC-5. The highest activity was observed against K562 cells (IC50: 5.04–6.51 μM). Selectivity indices showed that these complexes are less toxic than cisplatin. 3 had a similar viability kinetics on HeLa cells as cisplatin. Drug accumulation studies in HeLa cells showed that the total gold uptake increased much faster than that of cisplatin pointing out that 3 more efficiently enters the cells than cisplatin. Furthermore, morphological and cell cycle analysis reveal that gold(III) complexes induced apoptosis in time- and dose-dependent manner.

BackgroundGlobal increase in ambient temperatures constitute a significant challenge to wild and cultivated plant species. Forward genetic analyses of individual temperature-responsive traits have resulted in the identification of several signaling and response components. However, a comprehensive knowledge about temperature sensitivity of different developmental stages and the contribution of natural variation is still scarce and fragmented at best.ResultsHere, we systematically analyze thermomorphogenesis throughout a complete life cycle in ten natural Arabidopsis thaliana accessions grown under long day conditions in four different temperatures ranging from 16 to 28 °C. We used Q10, GxE, phenotypic divergence and correlation analyses to assess temperature sensitivity and genotype effects of more than 30 morphometric and developmental traits representing five phenotype classes. We found that genotype and temperature differentially affected plant growth and development with variing strengths. Furthermore, overall correlations among phenotypic temperature responses was relatively low which seems to be caused by differential capacities for temperature adaptations of individual accessions.ConclusionGenotype-specific temperature responses may be attractive targets for future forward genetic approaches and accession-specific thermomorphogenesis maps may aid the assessment of functional relevance of known and novel regulatory components.

BackgroundPlant adaptation to limited phosphate availability comprises a wide range of responses to conserve and remobilize internal phosphate sources and to enhance phosphate acquisition. Vigorous restructuring of root system architecture provides a developmental strategy for topsoil exploration and phosphate scavenging. Changes in external phosphate availability are locally sensed at root tips and adjust root growth by modulating cell expansion and cell division. The functionally interacting Arabidopsis genes, LOW PHOSPHATE RESPONSE 1 and 2 (LPR1/LPR2) and PHOSPHATE DEFICIENCY RESPONSE 2 (PDR2), are key components of root phosphate sensing. We recently demonstrated that the LOW PHOSPHATE RESPONSE 1 - PHOSPHATE DEFICIENCY RESPONSE 2 (LPR1-PDR2) module mediates apoplastic deposition of ferric iron (Fe3+) in the growing root tip during phosphate limitation. Iron deposition coincides with sites of reactive oxygen species generation and triggers cell wall thickening and callose accumulation, which interfere with cell-to-cell communication and inhibit root growth.ResultsWe took advantage of the opposite phosphate-conditional root phenotype of the phosphate deficiency response 2 mutant (hypersensitive) and low phosphate response 1 and 2 double mutant (insensitive) to investigate the phosphate dependent regulation of gene and protein expression in roots using genome-wide transcriptome and proteome analysis. We observed an overrepresentation of genes and proteins that are involved in the regulation of iron homeostasis, cell wall remodeling and reactive oxygen species formation, and we highlight a number of candidate genes with a potential function in root adaptation to limited phosphate availability. Our experiments reveal that FERRIC REDUCTASE DEFECTIVE 3 mediated, apoplastic iron redistribution, but not intracellular iron uptake and iron storage, triggers phosphate-dependent root growth modulation. We further highlight expressional changes of several cell wall-modifying enzymes and provide evidence for adjustment of the pectin network at sites of iron accumulation in the root.ConclusionOur study reveals new aspects of the elaborate interplay between phosphate starvation responses and changes in iron homeostasis. The results emphasize the importance of apoplastic iron redistribution to mediate phosphate-dependent root growth adjustment and suggest an important role for citrate in phosphate-dependent apoplastic iron transport. We further demonstrate that root growth modulation correlates with an altered expression of cell wall modifying enzymes and changes in the pectin network of the phosphate-deprived root tip, supporting the hypothesis that pectins are involved in iron binding and/or phosphate mobilization.