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Increasing plants photosynthetic efficienc y is a major challenge that must be addressed in order to cover the food demands of the growing population in the changing climate. Photosynthes i s is greatly limited at the initial carboxylation reaction, where CO2 is converted to the organic acid 3-PGA, catalyzed by the RuBisCO enzyme. RuBisCO has poor affinity for CO2, but also the CO2 concentration at the RuBisCO site is limited by the diffusion of atmospheric CO2 through the various leaf compartments to the reaction site. Beyond genetic engineer-ing, nanotechnology can offer a materials-based approach for enhancing photosynthesis, and yet, it has mostly been explored for the light-dependent reactions. In this work, we developed polyethyleneimine-based nanoparticl e s for enhancing the carbox-ylation reaction. We demonstrate that the nanoparticles can capture CO2 in the form of bicarbonate and increase the CO2 that reacts with the RuBisCO enzyme, enhancing the 3-PGA production in in vitro assays by 20%. The nanoparticles can be introduced to the plant via leaf infiltration and, because of the functionalization with chitosan oligomers, they do not induce any toxic effect to the plant. In the leaves, the nanoparticles localize in the apoplastic space but also spontaneously reach the chloroplasts where photosynthetic activity takes place. Their CO2 loading-dependent fluorescence verifies that, in vivo, they maintain their abi l i t y to capture CO2 and can be therefore reloaded with atmospheric CO2 while in planta. Our results contribute to the development of a nanomaterials-based CO2-concentrating mechanism in plants t h a t can potentially increase photosynthetic efficiency and overall plants CO2 storage. Funding Agencies|European Union [800926, 101042148]; Swedish Research Council [VR-2017-04910]; Swedish Government Strategic Research Area in Materials Science on Advanced Functional Materials at Linkoping University [2009-00971]; MCIN/AEI [Ayuda RYC2021-031668-I]

Purpose Root exudation of organic acids (OAs) facilitates plant P uptake from soil, playing a key role in rhizosphere nutrient availability. However, OA exudation responses to CO2 concentrations and water availability remain largely untested. Methods We examined the effects of CO2 and water on OA exudates in three Australian woodland species: Eucalyptus tereticornis, Hakea sericea and Microlaena stipoides. Seedlings were grown in a glasshouse in low P soil, exposed to CO2 (400 ppm [aCO2] or 540 ppm [eCO2]) and water treatments (100% water holding capacity [high-watered] or 25–50% water holding capacity [low-watered]). After six weeks, we collected OAs from rhizosphere soil (OArhizo) and trap solutions in which washed roots were immersed (OAexuded). Results For E. tereticornis, the treatments changed OArhizo composition, driven by increased malic acid in plants exposed to eCO2 and increased oxalic acid in low-watered plants. For H. sericea, low-watered plants had higher OAexuded per plant (+ 116%) and lower OArhizo per unit root mass (–77%) associated with larger root mass but fewer cluster roots. For M. stipoides, eCO2 increased OAexuded per plant (+ 107%) and per unit root mass (+ 160%), while low-watered plants had higher citric and lower malic acids for OArhizo and OAexuded: changes in OA amounts and composition driven by malic acid were positively associated with soil P availability under eCO2. Conclusion We conclude that eCO2 and altered water availability shifted OAs in root exudates, modifying plant–soil interactions and the associated carbon and nutrient economy.

Key message Elevated methylglyoxal levels contribute to ammonium-induced growth disorders in Arabidopsis thaliana. Methylglyoxal detoxification pathway limitation, mainly the glyoxalase I activity, leads to enhanced sensitivity of plants to ammonium nutrition. Abstract Ammonium applied to plants as the exclusive source of nitrogen often triggers multiple phenotypic effects, with severe growth inhibition being the most prominent symptom. Glycolytic flux increase, leading to overproduction of its toxic by-product methylglyoxal (MG), is one of the major metabolic consequences of long-term ammonium nutrition. This study aimed to evaluate the influence of MG metabolism on ammonium-dependent growth restriction in Arabidopsis thaliana plants. As the level of MG in plant cells is maintained by the glyoxalase (GLX) system, we analyzed MG-related metabolism in plants with a dysfunctional glyoxalase pathway. We report that MG detoxification, based on glutathione-dependent glyoxalases, is crucial for plants exposed to ammonium nutrition, and its essential role in ammonium sensitivity relays on glyoxalase I (GLXI) activity. Our results indicated that the accumulation of MG-derived advanced glycation end products significantly contributes to the incidence of ammonium toxicity symptoms. Using A. thaliana frostbite1 as a model plant that overcomes growth repression on ammonium, we have shown that its resistance to enhanced MG levels is based on increased GLXI activity and tolerance to elevated MG-derived advanced glycation end-product (MAGE) levels. Furthermore, our results show that glyoxalase pathway activity strongly affects cellular antioxidative systems. Under stress conditions, the disruption of the MG detoxification pathway limits the functioning of antioxidant defense. However, under optimal growth conditions, a defect in the MG detoxification route results in the activation of antioxidative systems.

During the growth season, northern forests in Sweden daily receive more hours of far-red (FR)-enriched light or twilight (shade) as compared to southern forests. Norway spruce (shade-tolerant) are adapted to latitudinal variation in twilight characterized by a northward increase in FR requirement to maintain growth. Shade is a stressful condition that affects plant growth and increases plant's susceptibility to pathogen attack. Lignin plays a central role in plant defense and its metabolism is regulated by light wavelength composition (light quality). In the current work, we studied regulation of lignin synthesis and defense-related genes (growth-defense trade-offs) in response to shade in Norway spruce. In most angiosperms, light promotes lignin synthesis, whereas shade decreases lignin production leading to weaker stem, which may make plants more disease susceptible. In contrast, enhanced lignin synthesis was detected in response to shade in Norway spruce. We detected a higher number of immunity/defense-related genes up-regulated in northern populations as compared to south ones in response to shade. Enhanced lignin synthesis coupled with higher defense-related gene expression can be interpreted as an adaptive strategy for better survival in northern populations. Findings will contribute to ensuring deployment of well-adapted genetic material and identifying tree families with enhanced disease resistance.

Despite significant research efforts, the question of whether rising atmospheric CO2 concentrations (Ca) affect leaf respiration remains unanswered. Here, I reanalyse published hydrogen isotope abundances in starch glucose of sunflower leaves. I report that, as Ca increases from 450 to 1500 ppm, respiration by the oxidative pentose phosphate pathway in chloroplasts increases from 0 to ≈ 5% relative to net carbon assimilation. This is consistent with known regulatory properties of the pathway. Summarising recent reports of metabolic fluxes in plant leaves, a picture emerges in which mitochondrial processes are distinctly less important for overall respiration than the oxidative pentose phosphate pathways in chloroplasts and the cytosol. Regulatory properties of these pathways are consistent with observations of lower-than-expected stimulations of photosynthesis in response to increasing Ca. Reported advances in understanding leaf respiratory mechanisms may enable modelling and prediction of respiration effects (inter alia) on biosphere-atmosphere CO2 exchange and plant performance under climate change.

The phytochrome (phy)-PHYTOCHROME-INTERACTING FACTOR (PIF) sensory module perceives and transduces light signals to direct target genes (DTGs), which then drive the adaptational responses in plant growth and development appropriate to the prevailing environment. These signals include the first exposure of etiolated seedlings to sunlight upon emergence from subterranean darkness and the change in color of the light that is filtered through, or reflected from, neighboring vegetation (“shade”). Previously, we identified three broad categories of rapidly signal-responsive genes: those repressed by light and conversely induced by shade; those repressed by light, but subsequently unresponsive to shade; and those responsive to shade only. Here, we investigate the potential role of epigenetic chromatin modifications in regulating these contrasting patterns of phy-PIF module-induced expression of DTGs in Arabidopsis (Arabidopsis thaliana). Using RNA-seq and ChIP-seq to determine time-resolved profiling of transcript and histone 3 lysine 4 trimethylation (H3K4me3) levels, respectively, we show that, whereas the initial dark-to-light transition triggers a rapid, apparently temporally coincident decline of both parameters, the light-to-shade transition induces similarly rapid increases in transcript levels that precede increases in H3K4me3 levels. Together with other recent findings, these data raise the possibility that, rather than being causal in the shade-induced expression changes, H3K4me3 may function to buffer the rapidly fluctuating shade/light switching that is intrinsic to vegetational canopies under natural sunlight conditions.

UDP-glucose (UDPG) pyrophosphorylase (UGPase) catalyzes a reversible reaction, producing UDPG, which serves as an essential precursor for hundreds of glycosyltransferases in all organisms. In this study, activities of purified UGPases from sugarcane and barley were found to be reversibly redox modulated in vitro through oxidation by hydrogen peroxide or oxidized glutathione (GSSG) and through reduction by dithiothreitol or glutathione. Generally, while oxidative treatment decreased UGPase activity, a subsequent reduction restored the activity. The oxidized enzyme had increased Km values with substrates, especially pyrophosphate. The increased Km values were also observed, regardless of redox status, for UGPase cysteine mutants (Cys102Ser and Cys99Ser for sugarcane and barley UGPases, respectively). However, activities and substrate affinities (Kms) of sugarcane Cys102Ser mutant, but not barley Cys99Ser, were still prone to redox modulation. The data suggest that plant UGPase is subject to redox control primarily via changes in the redox status of a single cysteine. Other cysteines may also, to some extent, contribute to UGPase redox status, as seen for sugarcane enzymes. The results are discussed with respect to earlier reported details of redox modulation of eukaryotic UGPases and regarding the structure/function properties of these proteins.

Coriaria nepalensis Wall. (Coriariaceae) is a nitrogen-fixing shrub which forms root nodules with the actinomycete Frankia. Oils and extracts of C. nepalensis have been reported to be bacteriostatic and insecticidal, and C. nepalensis bark provides a valuable tannin resource. Here, by combining PacBio HiFi sequencing and Hi-C scaffolding techniques, we generated a haplotype-resolved chromosome-scale genome assembly for C. nepalensis. This genome assembly is approximately 620 Mb in size with a contig N50 of 11 Mb, with 99.9% of the total assembled sequences anchored to 40 pseudochromosomes. We predicted 60,862 protein-coding genes of which 99.5% were annotated from databases. We further identified 939 tRNAs, 7,297 rRNAs, and 982 ncRNAs. The chromosome-scale genome of C. nepalensis is expected to be a significant resource for understanding the genetic basis of root nodulation with Frankia, toxicity, and tannin biosynthesis.

Veronica peregrina Linnaeus (1753: 14) was described in the protologue as “Veronica floribus solitariis sessilibus, foliis lanceolato-linearibus glabris obtusis integerrimis, caule erecto”, a phrase-name that was quoted directly from his previous treatment in Flora suecica (Linnaeus 1745: 6). Linnaeus (1753) stated about the origin of the plant: “Habitat in Europae hortis, arvisque” and also cited one synonym: “Veronica terrestris annua, folio polygoni, flore albo. Moris. Hist. 2. p. 322, sect. 3. t. 24. f. 19” (Morison 1680), based on material from England.

Microalgal biomass may have biostimulating effects on plants and seeds due to its phytohormonal content, and harnessing this biostimulating effect could contribute to sustainable agriculture. Two Nordic strains of freshwater microalgae species Chlorella vulgaris and Scenedesmus obliquus were each cultivated in a photobioreactor receiving untreated municipal wastewater. The algal biomass and the supernatant after algal cultivation were tested on tomato and barley seeds for biostimulating effects. Intact algal cells, broken cells, or harvest supernatant were applied to the seeds, and germination time, percentage and germination index were evaluated. Seeds treated with C. vulgaris, in particular intact cells or supernatant, had up to 25 percentage units higher germination percentage after 2 days and an overall significantly faster germination time (germinated on average between 0.5 and 1 day sooner) than seeds treated with S. obliquus or the control (water). The germination index was higher in C. vulgaris treatments than in the control for both tomato and barley, and this was observed for both broken and intact cells as well as supernatant. The Nordic strain of C. vulgaris cultivated in municipal wastewater thus shows potential for use as biostimulant in agriculture, adding novel economic and sustainability benefits.

Sensing carbohydrate availability is essential for plants to coordinate their growth and development. In Arabidopsis thaliana, TREHALOSE 6-PHOSPHATE SYNTHASE 1 (TPS1) and its product, trehalose 6-phosphate (T6P), are important for the metabolic control of development. tps1 mutants are embryo lethal and unable to flower when embryogenesis is rescued. T6P regulates development in part through inhibition of SUCROSE NON-FERMENTING1 RELATED KINASE1 (SnRK1). Here, we explored the role of SnRK1 in T6P-mediated plant growth and development using a combination of a mutant suppressor screen and genetic, cellular, and transcriptomic approaches. We report non-synonymous amino acid substitutions in the catalytic KIN10 and regulatory SNF4 subunits of SnRK1 that can restore both embryogenesis and flowering of tps1 mutant plants. The identified SNF4 point mutations disrupt the interaction with the catalytic subunit KIN10. Contrary to the common view that the two A. thaliana SnRK1 catalytic subunits act redundantly, we found that loss-of-function mutations in KIN11 are unable to restore embryogenesis and flowering, highlighting the important role of KIN10 in T6P signalling. ispartof: New Phytologist vol:235 issue:1 ispartof: location:England status: Published online

Forests are at increasing risk from pathogen outbreak. Climate change for example enhance the risk of local disease outbreaks, and naturalization of exotic pathogens may follow human activities, warranting robust pest surveillance routines to support forest management. Melampsora pinitorqua (pine twisting rust) is of concern in Swedish forestry, and here we evaluate the use of visible rust scores (VRS) on its obligate summer host, European aspen (Populus tremula) as a tool for quantification of the pathogen. With use of species-specific primers, we could detect the native rust, but we failed to detect two exotic rusts (M. medusae and M. larici-populina). We found that aspen genotype determined the presence of fungal genetic markers (amplifying the ITS2 region of the fungal rDNA sequence) as well as DNA sequences specific to M. pinitorqua. We correlated VRS with the amount of fungal DNA in the same leaf, and we related the findings to aspen genotype-specific parameters such as the ability to synthesize and store leaf condensed tannins (CT). At the genotype level both positive and negative relationships were observed between CTs, fungal markers, and rust infestations. However, at the population level, foliar CT concentrations correlated negatively with general fungal- and rust-specific marker abundances. Our results, therefore, do not support the use of VRS to assess Melampsora infestation in Aspen. They do, however, suggest that the relationship between European aspen and rust infestation may be characterized as autochthonous in northern Sweden.

Plastids are found in all plant cell types. However, most extraction methods to study these organelles are performed at the organ level (e.g., leaf, root, fruit) and do not allow for tissue-specific resolution, which hinders our understanding of their physiology. Therefore, IPTACT (Isolation of Plastids TAgged in specific Cell Types) was developed to isolate plastids in a tissue-specific manner in Arabidopsis thaliana (Arabidopsis). Plastids are biotinylated using one-shot transgenic lines, and tissue specificity is achieved with a suitable promoter as long as such a promoter exists. Cell-specific biotinylated plastids are then isolated with 2.8-µm streptavidin beads. Plastids extracted by IPTACT are suitable for RNA or protein isolation and subsequent tissue-specific OMICs analyses. This method provides the user with a powerful tool to investigate plastidial functions at cell-type resolution. Furthermore, it can easily be combined with studies using diverse genetic backgrounds and/or different developmental or stress conditions.

Main conclusion The xyloglucans of all aquatic Araceae species examined had unusual structures compared with those of other non-commelinid monocotyledon families previously examined. Abstract The aquatic Araceae species Lemna minor was earlier shown to have xyloglucans with a different structure from the fucogalactoxyloglucans of other non-commelinid monocotyledons. We investigated 26 Araceae species (including L. minor), from five of the seven subfamilies. All seven aquatic species examined had xyloglucans that were unusual in having one or two of three features: L. minor (Lemnoideae) and Orontium aquaticum (Orontioideae)]; no fucosylation [L. minor (Lemnoideae), Cryptocoryne aponogetonifolia, and Lagenandra ovata (Aroideae, Rheophytes clade)]; and > 14% oligosaccharide units with S or D side chains [Spirodela polyrhiza and Landoltia punctata (Lemnoideae) and Pistia stratiotes (Aroideae, Dracunculus clade)]. Orontioideae and Lemnoideae are the two most basal subfamilies, with all species being aquatic, and Aroideae is the most derived. Two terrestrial species [Dieffenbachia seguine and Spathicarpa hastifolia (Aroideae, Zantedeschia clade)] also had xyloglucans without fucose indicating this feature was not unique to aquatic species.

Proanthocyanidins (PAs) are polymeric phenolic compounds found in plants and used in many industrial applications. Despite strong evidence of herbivore and pathogen resistance-related properties of PAs, their in planta function is not fully understood. Determining the location and dynamics of PAs in plant tissues and cellular compartments is crucial to understand their mode of action. Such an approach requires microscopic localization with fluorescent dyes that specifically bind to PAs. Such dyes have hitherto been lacking. Here, we show that 4-dimethylaminocinnamaldehyde (DMACA) can be used as a PA-specific fluorescent dye that allows localization of PAs at high resolution in cell walls and inside cells using confocal microscopy, revealing features of previously unreported wall-bound PAs. We demonstrate several novel usages of DMACA as a fluorophore by taking advantage of its double staining compatibility with other fluorescent dyes. We illustrate the use of the dye alone and its co-localization with cell wall polymers in different Populus root tissues. The easy-to-use fluorescent staining method, together with its high photostability and compatibility with other fluorogenic dyes, makes DMACA a valuable tool for uncovering the biological function of PAs at a cellular level in plant tissues. DMACA can also be used in other plant tissues than roots, however care needs to be taken when tissues contain compounds that autofluoresce in the red spectral region which can be confounded with the PA-specific DMACA signal.

Verbascum nigrum is the most widespread Verbascum species in Germany. But only less is known about its sites and associations. It is underrepresented in plant-sociologic releves. One reason for this is probably that it grows mainly within linear structures and unattended meadow banks. It grows along roadsides, roadside ditches, older embankment slops, river sides and shrubbery sides as well as in quarries and sand pits. Regionally unattended banks and slops of meadows and pastures are remarkable growing places. Contrary to elder literature Verbascum nigrum is found nowadays only seldom at deforestations. Verbascum nigrum is associated with species of the Artemisietea class (in a broader sence) especially with Urtica dioica, Tanacetum vulgare, Artemisia vulgare, Cirsium arvense, Silene latifolia subsp. alba, Poa angustifolia, Elymus repens, Hypericum perforatum and Rumex thyrsiflorus. Species of Molinio-Arrhenathereta like Arrhenatherum elatius, Holcus lanatus, Dactylis glomerata, Achillea millefolium, Plantago lanceolata and Galium album appear more or less regularlely. The disturbance of the roadsite growing places by too frequent mowing, milling and heavy trucks or burrowing of animals results in very open vegetation promoting Stellarietea species like Myosotis arvensis, Tripleurospermum inodorum, Lactuca serriola, Conyza canadensis, Bromus hordeaceus subsp. hordeaceus, Geranium pusillum, Papaver dubium, Papaver rhoeas. Its appearance at cemeteries and rural front gardens indicates that Verbascum nigrum is tolerated at such places. Without any doubt Verbascum nigrum has its focal point in grass-rich Artemisietea communities. Despite of occasionally appearing Arction communities rich in character species Verbascum nigrum should not be seen as a character species of an own Arction community because its steadiness is too low and such a community would be characterized by only one species whereas a characterizing species combination is missing. If necessary the stands can be seen as a basal or derivate community which would allow to cover a possible change of the plant sociological connection by changing environmental conditions., Braunschweiger geobotanische Arbeiten, vol. 14, p. 183

Objekt des Monats der UB Wien Aus dem Botanischen Garten der Universität Wien (Mai 2023) Meergrüner Blattbambus (Phyllostachys viridiglaucescens) Pflanzenfamilie: Poaceae, Unterfamilie Bambusoideae Wuchshöhe: in der Heimat bis zu 8 m, in Kultur deutlich niedriger Standort: Freiland Gruppe 20 Text: DIin Barbara Knickmann | Fotos: Rudolf Hromniak

Increasing drought phenomena pose a serious threat to agricultural productivity. Although plants have multiple ways to respond to the complexity of drought stress, the underlying mechanisms of stress sensing and signaling remain unclear. The role of the vasculature, in particular the phloem, in facilitating inter-organ communication is critical and poorly understood. Combining genetic, proteomic and physiological approaches, we investigated the role of AtMC3, a phloem-specific member of the metacaspase family, in osmotic stress responses in Arabidopsis thaliana. Analyses of the proteome in plants with altered AtMC3 levels revealed differential abundance of proteins related to osmotic stress pointing into a role of the protein in water-stress-related responses. Overexpression of AtMC3 conferred drought tolerance by enhancing the differentiation of specific vascular tissues and maintaining higher levels of vascular-mediated transportation, while plants lacking the protein showed an impaired response to drought and inability to respond effectively to the hormone abscisic acid. Overall, our data highlight the importance of AtMC3 and vascular plasticity in fine-tuning early drought responses at the whole plant level without affecting growth or yield.

In eukaryotes, mitochondrial ATP is mainly produced by the oxidative phosphorylation (OXPHOS) system, which is composed of 5 multiprotein complexes (complexes I–V). Analyses of the OXPHOS system by native gel electrophoresis have revealed an organization of OXPHOS complexes into supercomplexes, but their roles and assembly pathways remain unclear. In this study, we characterized an atypical mitochondrial ferredoxin (mitochondrial ferredoxin-like, mFDX-like). This protein was previously found to be part of the bridge domain linking the matrix and membrane arms of the complex I. Phylogenetic analysis suggested that the Arabidopsis (Arabidopsis thaliana) mFDX-like evolved from classical mitochondrial ferredoxins (mFDXs) but lost one of the cysteines required for the coordination of the iron-sulfur (Fe-S) cluster, supposedly essential for the electron transfer function of FDXs. Accordingly, our biochemical study showed that AtmFDX-like does not bind an Fe-S cluster and is therefore unlikely to be involved in electron transfer reactions. To study the function of mFDX-like, we created deletion lines in Arabidopsis using a CRISPR/Cas9-based strategy. These lines did not show any abnormal phenotype under standard growth conditions. However, the characterization of the OXPHOS system demonstrated that mFDX-like is important for the assembly of complex I and essential for the formation of complex I-containing supercomplexes. We propose that mFDX-like and the bridge domain are required for the correct conformation of the membrane arm of complex I that is essential for the association of complex I with complex III2 to form supercomplexes.

Fast unbemerkt hat sich ein Wandel der Ruderalvegetation Mitteleuropas in den letzten Jahrzehnten vollzogen; inzwischen finden sich an den Verkehrsanlagen die größten mehr oder minder zusammenhängenden Ruderalflächen in Mitteleuropa. Infolge der geänderten Transportverhältnisse liegt das Augenmerk der Ausbreitung von gebietsfremden Pflanzenarten vor allem auf Straßen und Autobahnen. Wir haben nun erstmals eine Checkliste von salztoleranten Gefäßpflanzen an deutschen Straßenrändern aufgestellt. Einen deutlichen Fortschritt bei der Auswertung gegenüber der alleinigen Verwendung der Salzzahlen von ELLENBERG (ELLENBERG & LEUSCHNER 2010) ergab die eigene Analyse der Salzkonzentrationen im Wurzelbereich von Ruderalpflanzen sowie die Samenkeimung in definierten Kochsalzlösungen, vor allem aber die Auswertung der mitteleuropäischen Literatur, insbesondere der „Flora indicativa“ von LANDOLT & al. (2007). Auf diese Weise umfasst unsere Checkliste immerhin 250 krautige Arten und mindestens 16 Gehölze. Da die Ausbreitung von halotoleranten Arten trotz milder Winter und damit einhergehender geringerer Verwendung von Auftausalzen weiter fortschreitet, stellen wir die Hypothese auf, dass eine (schwache) Salztoleranz einen Konkurrenzvorteil für die Etablierung von Pflanzen am Straßenrand darstellt., A change of the ruderal vegetation of Central Europe happened nearly unnoticed during the last years. In the meanwhile, the largest more or less connected ruderal areas can be found in Central Europe along traffic infrastructure. Due to the altered conditions in traffic, the focus of the spreading of alien plants is now on streets and motorways. A checklist of salt tolerant plants of Germany is presented here for the first time. A main progress in the evaluation was made by using own analyses of the salt content of the rhizosphere of ruderal plants, experiments on germination in defined NaCl solution, and mainly by the evaluation of the Central European literature, especially the “Flora indicativa” by LANDOLT & al. (2007) in addition to the salt indicator values regarding to ELLENBERG (ELLENBERG & LEUSCHNER 2010). By doing so, our own checklist summarizes 250 herbaceous species and at least 16 woody plants. Because the spreading of halotolerant plants is going on despite of mild winters and concomitant less road salt, we formulate the hypothesis that a weak salt tolerance is an ad-vantage for the establishing of plants along roadsides., Floristische Rundbriefe, 55 (2021), 60-86

Wood decay resistance (WDR) is marking the value of wood utilization. Many trees of the Lauraceae have exceptional WDR, as evidenced by their use in ancient royal palace buildings in China. However, the genetics of WDR remain elusive. Here, through comparative genomics, we revealed the unique characteristics related to the high WDR in Lauraceae trees. We present a 1.27-Gb chromosome-level assembly for Lindera megaphylla (Lauraceae). Comparative genomics integrating major groups of angiosperm revealed Lauraceae species have extensively shared gene microsynteny associated with the biosynthesis of specialized metabolites such as isoquinoline alkaloids, flavonoid, lignins and terpenoid, which play significant roles in WDR. In Lauraceae genomes, tandem and proximal duplications (TD/PD) significantly expanded the coding space of key enzymes of biosynthesis pathways related to WDR, which may enhance the decay resistance of wood by increasing the accumulation of these compounds. Among Lauraceae species, genes of WDR-related biosynthesis pathways showed remarkable expansion by TD/PD and conveyed unique and conserved motifs in their promoter and protein sequences, suggesting conserved gene collinearity, gene expansion and gene regulation supporting the high WDR. Our study thus reveals genomic profiles related to biochemical transitions among major plant groups and the genomic basis of WDR in the Lauraceae.

Braunschweiger geobotanische Arbeiten, vol. 14, p. 147

Cyclotides are an intriguing class of structurally stable circular miniproteins of plant origin with numerous potential pharmaceutical and agricultural applications. To investigate the occurrence of cyclotides in Sri Lankan flora, 50 medicinal plants were screened, leading to the identification of a suite of new cyclotides from Geophila repens of the family Rubiaceae. Cycloviolacin O2-like (cyO2-like) gere 1 and the known cyclotide kalata B7 (kB7) were among the cyclotides characterized at the peptide and/or transcript level together with several putative enzymes, likely involved in cyclotide biosynthesis. Five of the most abundant cyclotides were isolated, sequenced, structurally characterized, and screened in antimicrobial and cytotoxicity assays. All gere cyclotides showed cytotoxicity (IC50 of 2.0-10.2 mu M), but only gere 1 inhibited standard microbial strains at a minimum inhibitory concentration of 4-16 mu M. As shown by immunohistochemistry, large quantities of the cyclotides were localized in the epidermis of the leaves and petioles of G. repens. Taken together with the cytotoxicity and membrane permeabilizing activities, this implicates gere cyclotides as potential plant defense molecules. The presence of cyO2-like gere 1 in a plant in the Rubiaceae supports the notion that phylogenetically distant plants may have coevolved to express similar cytotoxic cyclotides for a specific functional role, most likely involving host defense.

Adventitious roots or shoot-borne roots transdifferentiate from cells close to vascular tissues after cell reprogramming, which is associated with increased transcriptional activity. Recently, Garg et al. provided a genome-wide landscape of transcriptional signatures during the early stages of adventitious root initiation in rice and showed that conserved transcription factors acquire species-specific function.

Generally, net O-2 consumption becomes dominant when photosynthesis is suppressed at night in green organisms. Here, Bag et al. show that Scots pine and Norway spruce needles display strong O-2 consumption when extremely low temperatures coincide with high solar irradiation during early spring. Green organisms evolve oxygen (O-2) via photosynthesis and consume it by respiration. Generally, net O-2 consumption only becomes dominant when photosynthesis is suppressed at night. Here, we show that green thylakoid membranes of Scots pine (Pinus sylvestris L) and Norway spruce (Picea abies) needles display strong O-2 consumption even in the presence of light when extremely low temperatures coincide with high solar irradiation during early spring (ES). By employing different electron transport chain inhibitors, we show that this unusual light-induced O-2 consumption occurs around photosystem (PS) I and correlates with higher abundance of flavodiiron (Flv) A protein in ES thylakoids. With P700 absorption changes, we demonstrate that electron scavenging from the acceptor-side of PSI via O-2 photoreduction is a major alternative pathway in ES. This photoprotection mechanism in vascular plants indicates that conifers have developed an adaptative evolution trajectory for growing in harsh environments.

Växtsonifiering är processen av att översätta elektrisk aktivitet i växter till ljud och ingår huvudsakligen i två discipliner, ljudkonst och botanik. Syftet med denna studie är att bidra med kunskap om hur växtsonifiering kan användas i både konstnärliga och naturvetenskapliga syften. I studien undersöks konstnärliga möjligheter genom tre musikaliska verk som är skapade via växtsonifiering samt genom analys av konventioner inom modern växtmusik. Naturvetenskapliga användningsområden för växtsonifiering undersöks i studien genom standardiserade experiment på tre olika växter, en monstera [Monstera deliciosa] och två separata rosengeranier [Pelargonium graveolens]. Genom att utsätta växterna för olika typer av beröring samtidigt som de är uppkopplade till en synthesizer via två elektroder undersöks det ifall reaktioner från växterna uppenbarar sig i de data som genereras. Studien visar på att växtsonifiering kan vara ett användbart verktyg till att bland annat skapa ambienta ljudlandskap och musik, men att det även finns fler konstnärliga möjligheter. Det övergripande resultatet av experimenten visar på att växtsonifiering kan vara ett användbart komplement till analys av visuella data, men att det enskilt inte är den bästa metoden för studerandet av växters fysiologi. Studien visar även på hur växtsonifiering kan brukas i syfte att förstå saker om naturen som inte är synligt för blotta ögat

The work with this thesis has focused on evolutionary relationships in the Rubioideae, the most species-rich subfamily of the large and diverse coffee family (Rubiaceae). Despite considerable efforts during the last decades, uncertainty regarding several relationships in this group has remained, either as a result of unconvincing statistic support, incongruent results, or insufficient taxon sampling. Here, sequence data were obtained using both traditional and recently developed molecular methods, substantially expanding the amount of sequence data available for phylogenetic analysis within Rubioideae. Leveraging considerable amounts of data from a comprehensive sample of taxa showed to be highly effective in resolving phylogenetic relationships in the group, including its most recalcitrant parts. The results indicated that nuclear gene tree discordance at short internodes were frequently consistent with high levels of incomplete lineage sorting (ILS) owing to rapid diversification in the group. This finding may explain why some relationships have been notoriously difficult to resolve. Furthermore, while the results from coalescent simulations indicated that ILS alone can explain most of the observed cytonuclear incongruence, plastome introgression may be the more likely explanation in at least one case. Within Rubioideae the tribe Anthospermeae was studied in more detail. The phylogenetic analyses of this tribe revealed several cases and types of topological incongruence. Nevertheless, the deepest splits of the Anthospermeae phylogeny were congruent among analyses, but partly inconsistent with the traditional subtribal delimitation of the tribe. The infratribal classification of Anthospermeae was therefore partly updated. Unusual plastome features were also found within Anthospermeae, comprising large inversions and (putative) mitochondrial-to-plastome DNA transfer. With few other exceptions, plastomes across the Rubioideae tend to be highly conserved and typically conform to the canonical structure, gene content, and gene order of the majority of flowering plants.

The postembryonic formation of lateral roots (LRs) starts in internal root tissue, the pericycle. An important question of LR development is how the connection of the primary root vasculature with that of the emerging LR is established and whether the pericycle and/or other cell types direct this process. Here, using clonal analysis and time-lapse experiments, we show that both the procambium and pericycle of the primary root (PR) affect the LR vascular connectivity in a coordinated manner. We show that during LR formation, procambial derivates switch their identity and become precursors of xylem cells. These cells, together with the pericycle-origin xylem, participate in the formation of what we call a “xylem bridge” (XB), which establishes the xylem connection between the PR and the nascent LR. If the parental protoxylem cell fails to differentiate, XB is still sometimes formed but via a connection with metaxylem cells, highlighting that this process has some plasticity. Using mutant analyses, we show that the early specification of XB cells is determined by CLASS III HOMEODOMAIN-LEUCINE ZIPPER (HD-ZIP III) transcription factors (TFs). Subsequent XB cell differentiation is marked by the deposition of secondary cell walls (SCWs) in spiral and reticulate/scalariform patterns, which is dependent on the VASCULAR-RELATED NAC-DOMAIN (VND) TFs. XB elements were also observed in Solanum lycopersicum, suggesting that this mechanism may be more widely conserved in plants. Together, our results suggest that plants maintain vascular procambium activity, which safeguards the functionality of newly established lateral organs by assuring the continuity of the xylem strands throughout the root system. ISSN:0960-9822 ISSN:1879-0445

Roughly 2 billion ha of land are degraded and in need of ecological restoration worldwide. Active restoration frequently involves revegetation, which leads to the dilemma of whether to conduct direct seeding or to plant nursery-grown seedlings. The choice of revegetation method can regulate plant survival and performance, with economic implications that ultimately feed back to our capacity to conduct restoration. We followed a peerreviewed protocol to develop a systematic map that collates, describes and catalogues the available studies on how seeding compares to planting in achieving restoration targets. We compiled a database with the characteristics of all retrieved studies, which can be searched to identify studies of particular locations and habitats, objectives of restoration, plant material, technical aspects, and outcomes measured. The search was made in eight languages and retrieved 3355 publications, of which 178 were retained. The systematic map identifies research gaps, such as a lack of studies in the global South, in tropical rainforests, and covering a long time period, which represent opportunities to expand field-based research. Additionally, many studies overlooked reporting on important technical aspects such as seed provenance and nursery cultivation methods, and others such as watering or seedling protection were more frequently applied for planting than for seeding, which limits our capacity to learn from past research. Most studies measured outcomes related to the target plants but avoided measuring general restoration outcomes or economic aspects. This represents a relevant gap in research, as the choice of revegetation method is greatly based on economic aspects and the achievement of restoration goals goes beyond the establishment of plants. Finally, we identified a substantial volume of studies conducted in temperate regions and over short periods (0–5 y). This research cluster calls for a future in-depth synthesis, potentially through meta-analysis, to reveal the overall balance between seeding and planting and assess whether the response to this question is mediated by species traits, environmental characteristics, or technical aspects. Besides identifying research clusters and gaps, the systematic map database allows managers to find the most relevant scientific literature on the appropriateness of seeding vs. planting for particular conditions, such as certain species or habitats., Spanish Ministerio de Ciencia, Innovacion y Universidades/FEDER RTI 2018-096187-J-100 RYC 2020-029407-I, Ministry of Science and Innovation, Spain (MICINN) TED2021.130976 B.I00, Consejeria de Economia, Conocimiento, Empresas y Universidad de la Junta de Andalucia/FEDER P18-RT-1927, Universidad de Granada / CBUA

We describe the dramatic shifts in translation that occur during seed maturation, germination, and seedling establishment. Using network analysis, we identify putative regulatory relationships and subsequently confirm some of them in vivo.Seed maturation is the developmental process that prepares the embryo for the desiccated waiting period before germination. It is associated with a series of physiological changes leading to the establishment of seed dormancy, seed longevity, and desiccation tolerance. We studied translational changes during seed maturation and observed a gradual reduction in global translation during seed maturation. Transcriptome and translatome profiling revealed specific reduction in the translation of thousands of genes. By including previously published data on germination and seedling establishment, a regulatory network based on polysome occupancy data was constructed: SeedTransNet. Network analysis predicted translational regulatory pathways involving hundreds of genes with distinct functions. The network identified specific transcript sequence features suggesting separate translational regulatory circuits. The network revealed several seed maturation-associated genes as central nodes, and this was confirmed by specific seed phenotypes of the respective mutants. One of the regulators identified, an AWPM19 family protein, PM19-Like1 (PM19L1), was shown to regulate seed dormancy and longevity. This putative RNA-binding protein also affects the translational regulation of its target mRNA, as identified by SeedTransNet. Our data show the usefulness of SeedTransNet in identifying regulatory pathways during seed phase transitions.

circle Recently, we reported estimates of anaplerotic carbon flux through the oxidative pentose phosphate pathway (OPPP) in chloroplasts into the Calvin- Benson cycle. These estimates were based on intramolecular hydrogen isotope analysis of sunflower leaf starch. However, the isotope method is believed to underestimate the actual flux at low atmospheric CO2 concentration (C-a).circle Since the OPPP releases CO2 and reduces NADP(+), it can be expected to affect leaf gas exchange under both rubisco- and RuBP-regeneration-limited conditions. Therefore, we expanded Farquhar-von Caemmerer-Berry models to account for OPPP metabolism. Based on model parameterisation with values from the literature, we estimated OPPP-related effects on leaf carbon and energy metabolism in the sunflowers analysed previously.circle We found that flux through the plastidial OPPP increases both above and below C-a approximate to 450 ppm (the condition the plants were acclimated to). This is qualitatively consistent with our previous isotope-based estimates, yet gas-exchange-based estimates are larger at low Ca.circle We discuss our results in relation to regulatory properties of the plastidial and cytosolic OPPP, the proposed variability of CO2 mesophyll conductance, and the contribution of day respiration to the A/C-i curve drop at high Ca. Furthermore, we critically examine the models and parameterisation and derive recommendations for follow-up studies.

Üvez (Sorbus domestica L.) meyvesi ülkemizin çoğu bölgesinde yetişebilen ve şifalı olduğuna inanılan bir meyvedir. Bu çalışmada, üvezin içeriğinde bulunan serbest radikal süpürücü antioksidan maddelerin etkinliği ve antikolinerjik olarak enzim inhibisyonu araştırılmıştır. Antioksidan kapasitesi bakır iyonlarını indirgeme (Cu2+) (CUPRAC) testi, antikolinerjik etkinliği ise Asetilkolinesteraz (AChE) ve Bütirilkolinesteraz (BChE) enzimleri üzerindeki inhibisyonu ile belirlenmiştir. Ayrıca tıbbi açıdan koruyucu ya da iyileştirici özelliği olabilecek bu meyvenin muhtemel sitotoksik ve genotoksik etkileri in vitro ortamda insan meme kanseri hücre kültürü (MCF-7) üzerinde çalışılmıştır. Sitotoksik etkinliği WST-1 testi ile incelenmiştir. Genotoksik etkiniği ise Komet testi ile araştırılmıştır. CUPRAC testi ile üvez meyvesinin sulu ekstrasiyonuna ait farklı konsantrasyonların (5,10,15,20,25,30 μg/mL) etkinliği incelendiğinde standart antiosidanlara göre (α-Tokoferol ve Trolox) daha yüksek olduğu bulunmuştur. Antikolinerjik aktivitesi incelendiğinde ise Kolinesteraz enziminin standart inhibitörü olan Takrin’e karşı oldukça yüksek akviteye sahip olduğu görülmüştür. Sitotoksik etkinlik WST-1 ile incelendiğinde hücre kültürü üzerinde %50 inhibisyon konsantrasyounun (IC50) en yüksek ekstraksiyon (500000 ppm) oranında dahil elde edilemediği belirlenmiştir. Komet testi ile genotoksisite aktivitesi araştırılmış ve az miktarda da olsa genotoksik etki gösterdiği görülmüştür. Rowan (Sorbus domestica L.) fruit is a fruit that can be grown in most regions of our country and is believed to be medicinal. In this study, the effectiveness of free radical scavenging antioxidants in rowan content and enzyme inhibition as anticholinergic were investigated. Its antioxidant capacity was determined by the reduction of copper ions (Cu2+) (CUPRAC) test, and its anticholinergic activity was determined by inhibition of Acetylcholinesterase (AChE) and Butyrylcholinesterase (BChE) enzymes. In addition, the possible cytotoxic and genotoxic effects of this fruit, which may have medicinal or curative properties, were studied in vitro on human breast cancer cell culture (MCF-7). Its cytotoxic activity was examined by the WST-1 test. Its genotoxic effect was investigated by the Comet test.When the efficacy of different concentrations (5,10,15,20,25,30 μg/mL) of the aqueous extraction of rowan fruit was examined with the CUPRAC test, it was found that it was higher than the standard antioxidants (α-Tocopherol and Trolox). When its anticholinergic activity was examined, it was observed that it had a very high activity against Tacrine, the standard inhibitor of the Cholinesterase enzyme. When the cytotoxic activity was examined with WST-1, it was determined that 50% inhibition concentration (IC50) on cell culture could not be obtained even at the highest extraction rate (50000 ppm). Genotoxicity activity was investigated with the comet test and it was observed that it had a small amount of genotoxic effect