Poplars are among the fastest-growing trees and significant resources in agriculture and forestry. However, rapid growth requires a large water consumption, and irrigation water provides a natural means for pathogen spread. That includes members of Phytophthora spp. that have proven to be a global enemy to forests. With the known adaptability to new hosts, it is only a matter of time for more aggressive Phytophthora species to become a threat to poplar forests and plantations. Here, the effects of artificial inoculation with two different representatives of aggressive species (P. cactorum and P. plurivora) were analyzed in the proteome of the Phytophthora-tolerant hybrid poplar clone T-14 [Populus tremula L. 70 × (Populus × canescens (Ait.) Sm. 23)]. Wood microcore samples were collected at the active necrosis borders to provide insight into the molecular processes underlying the observed tolerance to Phytophthora. The analysis revealed the impact of Phytophthora on poplar primary and secondary metabolism, including carbohydrate-active enzymes, amino acid biosynthesis, phenolic metabolism, and lipid metabolism, all of which were confirmed by consecutive metabolome and lipidome profiling. Modulations of enzymes indicating systemic response were confirmed by the analysis of leaf proteome, and sampling of wood microcores in distal locations revealed proteins with abundance correlating with proximity to the infection, including germin-like proteins, components of proteosynthesis, glutamate carboxypeptidase, and an enzyme that likely promotes anthocyanin stability. Finally, the identified Phytophthora-responsive proteins were compared to those previously found in trees with compromised defense against Phytophthora, namely, Quercus spp. and Castanea sativa. That provided a subset of candidate markers of Phytophthora tolerance, including certain ribosomal proteins, auxin metabolism enzymes, dioxygenases, polyphenol oxidases, trehalose-phosphate synthase, mannose-1-phosphate guanylyltransferase, and rhamnose biosynthetic enzymes. In summary, this analysis provided the first insight into the molecular mechanisms of hybrid poplar defense against Phytophthora and identified prospective targets for improving Phytophthora tolerance in trees.

• Klíčová slova
• Phytophthora cactorum, Phytophthora plurivora, Populus, biotic interaction, lipidome, metabolome, proteome,
• Publikační typ
• časopisecké články MeSH

BACKGROUND: Many regulatory circuits in plants contain steps of targeted proteolysis, with the ubiquitin proteasome system (UPS) as the mediator of these proteolytic events. In order to decrease ubiquitin-dependent proteolysis, we inducibly expressed a ubiquitin variant with Arg at position 48 instead of Lys (ubK48R). This variant acts as an inhibitor of proteolysis via the UPS, and allowed us to uncover processes that are particularly sensitive to UPS perturbation. RESULTS: Expression of ubK48R during germination leads to seedling death. We analyzed the seedling transcriptome, proteome and metabolome 24 h post ubK48R induction and confirmed defects in chloroplast development. We found that mutations in single genes can suppress seedling lethality, indicating that a single process in seedlings is critically sensitive to decreased performance of the UPS. Suppressor mutations in phototropin 2 (PHOT2) suggest that a contribution of PHOT2 to chloroplast protection is compromised by proteolysis inhibition. CONCLUSIONS: Overall, the results reveal protein turnover as an integral part of a signal transduction chain that protects chloroplasts during development.

• Klíčová slova
• Chlorophagy, Chloroplast development, Light signal transduction, Light stress, Photomorphogenesis, Phototropin, Ubiquitin K48 chains,
• MeSH
• chloroplasty genetika   metabolismus   MeSH
• metabolom MeSH
• proteasomový endopeptidasový komplex * genetika   metabolismus   MeSH
• proteolýza MeSH
• semenáček genetika   metabolismus   MeSH
• transkriptom MeSH
• ubikvitin * metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• proteasomový endopeptidasový komplex * MeSH
• ubikvitin * MeSH

Heat shock proteins 70 (HSP70s) are steadily gaining more attention in the field of plant biotic interactions. Though their regulation and activity in plants are much less well characterized than are those of their counterparts in mammals, accumulating evidence indicates that the role of HSP70-mediated defense mechanisms in plant cells is indispensable. In this review, we summarize current knowledge of HSP70 post-translational control in plants. We comment on the phytohormonal regulation of HSP70 expression and protein abundance, and identify a prominent role for cytokinin in HSP70 control. We outline HSP70s' subcellular localizations, chaperone activity, and chaperone-mediated protein degradation. We focus on the role of HSP70s in plant pathogen-associated molecular pattern-triggered immunity and effector-triggered immunity, and discuss the contribution of different HSP70 subfamilies to plant defense against pathogens.

• Klíčová slova
• Biotic interactions, HSP70, cytokinin, immunity, phytohormone, plant defense,
• MeSH
• imunita rostlin * MeSH
• proteiny tepelného šoku HSP70 * metabolismus   MeSH
• savci metabolismus   MeSH
• signální transdukce MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• proteiny tepelného šoku HSP70 * MeSH

BACKGROUND: Split-root systems (SRS) have many applications in plant sciences, but their implementation, depending on the experimental design, can be difficult and time-consuming. Additionally, the system is not exempt from limitations, since the time required for the establishment of the SRS imposes a limit to how early in plant development experiments can be performed. Here, we optimized and explained in detail a method for establishing a SRS in young Arabidopsis thaliana seedlings, both in vitro and in soil. RESULTS: We found that the partial de-rooting minimized the recovery time compared to total de-rooting, thus allowing the establishment of the split-root system in younger plants. Analysis of changes in the Arabidopsis leaf proteome following the de-rooting procedure highlighted the distinct metabolic alterations that totally and partially de-rooted plants undergo during the healing process. This system was also validated for its use in drought experiments, as it offers a way to apply water-soluble compounds to plants subjected to drought stress. By growing plants in a split-root system with both halves being water-deprived, it is possible to apply the required compound to one half of the root system, which can be cut from the main plant once the compound has been absorbed, thus minimizing rehydration and maintaining drought conditions. CONCLUSIONS: Partial de-rooting is the suggested method for obtaining split-root systems in small plants like Arabidopsis thaliana, as growth parameters, survival rate, and proteomic analysis suggest that is a less stressful procedure than total de-rooting, leading to a final rosette area much closer to that of uncut plants. Additionally, we provide evidence that split root-systems can be used in drought experiments where water-soluble compounds are applied with minimal effects of rehydration.

• Klíčová slova
• Arabidopsis thaliana, Drought stress, Phytohormones, Proteomics, Split-root systems,
• Publikační typ
• časopisecké články MeSH

Phytophthora is arguably one of the most damaging genera of plant pathogens. This pathogen is well suited to transmission via the international plant trade, and globalization has been promoting its spread since the 19th century. Early detection is essential for reducing its economic and ecological impact. Here, a shotgun proteomics approach was utilized for Phytophthora analysis. The collection of 37 Phytophthora isolates representing 12 different species was screened for species-specific peptide patterns. Next, Phytophthora proteins were detected in planta, employing model plants Solanum tuberosum and Hordeum vulgare. Although the evolutionarily conserved sequences represented more than 10% of the host proteome and limited the pathogen detection, the comparison between qPCR and protein data highlighted more than 300 protein markers, which correlated positively with the amount of P. infestans DNA. Finally, the analysis of P. palmivora response in barley revealed significant alterations in plant metabolism. These changes included enzymes of cell wall metabolism, ROS production, and proteins involved in trafficking. The observed root-specific attenuation in stress-response mechanisms, including the biosynthesis of jasmonates, ethylene and polyamines, and an accumulation of serotonin, provided the first insight into molecular mechanisms behind this particular biotic interaction.

• Klíčová slova
• Hordeum vulgare, P. infestans, P. palmivora, Phytophthora, Solanum tuberosum, leaf inoculation, proteomics,
• MeSH
• chromatografie kapalinová MeSH
• fyziologický stres MeSH
• hmotnostní spektrometrie MeSH
• ječmen (rod) enzymologie   metabolismus   mikrobiologie   MeSH
• listy rostlin metabolismus   mikrobiologie   MeSH
• metabolické sítě a dráhy MeSH
• nemoci rostlin mikrobiologie   MeSH
• peptidy metabolismus   MeSH
• Phytophthora infestans genetika   izolace a purifikace   MeSH
• polymerázová řetězová reakce MeSH
• proteom metabolismus   MeSH
• proteomika MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• rostlinné proteiny metabolismus   MeSH
• Solanum tuberosum metabolismus   mikrobiologie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• peptidy MeSH
• proteom MeSH
• reaktivní formy kyslíku MeSH
• rostlinné proteiny MeSH

Phytophthora cinnamomi is one of the most invasive tree pathogens that devastates wild and cultivated forests. Due to its wide host range, knowledge of the infection process at the molecular level is lacking for most of its tree hosts. To expand the repertoire of studied Phytophthora-woody plant interactions and identify molecular mechanisms that can facilitate discovery of novel ways to control its spread and damaging effects, we focused on the interaction between P. cinnamomi and sweet chestnut (Castanea sativa), an economically important tree for the wood processing industry. By using a combination of proteomics, metabolomics, and targeted hormonal analysis, we mapped the effects of P. cinnamomi attack on stem tissues immediately bordering the infection site and away from it. P. cinnamomi led to a massive reprogramming of the chestnut proteome and accumulation of the stress-related hormones salicylic acid (SA) and jasmonic acid (JA), indicating that stem inoculation can be used as an easily accessible model system to identify novel molecular players in P. cinnamomi pathogenicity.

• Klíčová slova
• Phytophthora cinnamomi, metabolomics, proteomics, sweet chestnut,
• MeSH
• cyklopentany metabolismus   MeSH
• dřevo MeSH
• Fagaceae metabolismus   mikrobiologie   MeSH
• homeostáza MeSH
• kořeny rostlin MeSH
• kyselina salicylová metabolismus   MeSH
• metabolomika MeSH
• nemoci rostlin mikrobiologie   MeSH
• oxylipiny metabolismus   MeSH
• Phytophthora patogenita   MeSH
• proteomika MeSH
• regulátory růstu rostlin metabolismus   MeSH
• signální transdukce MeSH
• vazebná místa MeSH
• výpočetní biologie MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• cyklopentany MeSH
• jasmonic acid MeSH Prohlížeč
• kyselina salicylová MeSH
• oxylipiny MeSH
• regulátory růstu rostlin MeSH

Cytokinin is a phytohormone involved in the regulation of diverse developmental and physiological processes in plants. Its potential in biotechnology and for development of higher-yield and more resilient plants has been recognized, yet the molecular mechanisms behind its action are far from understood. In this report, the roots of barley seedlings were explored as a new source to reveal as yet unknown cytokinin-responsive proteins for crop improvement. Here we found significant differences reproducibly observed for 178 proteins, for which some of the revealed cytokinin-responsive pathways were confirmed in metabolome analysis, including alterations phenylpropanoid pathway, amino acid biosynthesis and ROS metabolism. Bioinformatics analysis indicated a significant overlap between cytokinin response and response to abiotic stress. This was confirmed by comparing proteome and metabolome profiles in response to drought, salinity or a period of temperature stress. The results illustrate complex abiotic stress response in the early development of model crop plant and confirm an extensive crosstalk between plant hormone cytokinin and response to temperature stimuli, water availability or salinity stress.

• Klíčová slova
• Hordeum vulgare, ROS, abiotic stress, metabolome, phenylpropanoid biosynthesis, proteome, root, zeatin,
• Publikační typ
• časopisecké články MeSH

Cytokinin is an indispensable phytohormone responsible for physiological processes ranging from root development to leaf senescence. The term "cytokinin" refers to several dozen adenine-derived compounds occurring naturally in plants. Cytokinins (CKs) can be divided into various classes and forms; base forms are generally considered to be active while highly abundant cytokinin-N-glucosides (CKNGs), composed of a CK base irreversibly conjugated to a glucose molecule, are considered inactive. However, results from early CK studies suggest CKNGs do not always lack activity despite the perpetuation over several decades in the literature that they are inactive. Here we show that exogenous application of trans-Zeatin-N-glucosides (tZNGs, a specific class of CKNGs) to Arabidopsis results in CK response comparable to the application of an active CK base. These results are most apparent in senescence assays where both a CK base (tZ) and tZNGs (tZ7G, tZ9G) delay senescence in cotyledons. Further experiments involving root growth and shoot regeneration revealed tZNGs do not always have the same effects as tZ, and have largely distinct effects on the transcriptome and proteome. These data are in contrast to previous reports of CKNGs being inactive and raise questions about the function of these compounds as well as their mechanism of action.

• MeSH
• Arabidopsis růst a vývoj   metabolismus   MeSH
• cytokininy metabolismus   MeSH
• glukosidy metabolismus   MeSH
• kořeny rostlin růst a vývoj   metabolismus   MeSH
• regulátory růstu rostlin MeSH
• zeatin metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• cytokininy MeSH
• glukosidy MeSH
• regulátory růstu rostlin MeSH
• zeatin MeSH

Hydrogen peroxide promotes seed germination, but the molecular mechanisms underlying this process are unclear. This study presents the results of eggplant (Solanum melongena) germination analyses conducted at two different temperatures and follows the effect of hydrogen peroxide treatment on seed germination and the seed proteome. Hydrogen peroxide was found to promote eggplant germination in a way not dissimilar to that of increased temperature stimuli. LC-MS profiling detected 729 protein families, 77 of which responded to a temperature increase or hydrogen peroxide treatment. These differentially abundant proteins were found to be involved in a number of processes, including protein and amino acid metabolism, carbohydrate metabolism, and the glyoxylate cycle. There was a very low overlap between hydrogen peroxide and temperature-responsive proteins, highlighting the differences behind the seemingly similar outcomes. Furthermore, the observed changes from the seed proteome indicate that hydrogen peroxide treatment diminished the seed endogenous hydrogen peroxide pool and that a part of manifested positive hydrogen peroxide effect might be related to altered sensitivity to abscisic acid.

• Klíčová slova
• eggplant, germination, hydrogen peroxide, proteomics, seed, temperature,
• MeSH
• chromatografie kapalinová MeSH
• fyziologický stres účinky léků   MeSH
• hmotnostní spektrometrie MeSH
• klíčení účinky léků   MeSH
• metabolismus sacharidů účinky léků   MeSH
• peroxid vodíku farmakologie   MeSH
• regulace genové exprese u rostlin účinky léků   MeSH
• rostlinné proteiny metabolismus   MeSH
• Solanum melongena účinky léků   fyziologie   MeSH
• teplota MeSH
• vývojová regulace genové exprese účinky léků   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• peroxid vodíku MeSH
• rostlinné proteiny MeSH