Kurt V Fagerstedt

• PhD, Doc., Prof.
• Managing Director at University of Helsinki

Interactions between plant energy organelles, the chloroplasts and the mitochondria, are crucial for plant development and acclimation. These interactions occur at different levels including exchange of metabolites and reducing power, organelle signaling pathways and intracellular gas exchange. Mitochondrial retrograde stress signaling activates ex...

Plant respiratory burst oxidase homologs (RBOHs) are plasma membrane-localized NADPH oxidases that generate superoxide anion radicals, which then dismutate to H2O2, into the apoplast using cytoplasmic NADPH as an electron donor. PaRBOH1 is the most highly expressed RBOH gene in developing xylem as well as in a lignin-forming cell culture of Norway...

Monolignol transport during lignification is a partially solved puzzle: both the mechanism(s) and the transported form of monolignols are unknown in developing xylem of trees. We tested a hypothesis of an active, plasma membrane (PM)-localized transport of monolignol monomers, dimers, and/or glucosidic forms with membrane vesicles prepared of devel...

A comparative transcriptomic study and a single-cell metabolome analysis were combined to determine whether parenchymal ray cells contribute to the biosynthesis of monolignols in the lignifying xylem of Norway spruce (Picea abies). Ray parenchymal cells may function in the lignification of upright tracheids by supplying monolignols. To test this hy...

In the version of this article initially published, there was a mistake in the calculation of the nucleotide mutation rate per site per generation: 1 × 10⁻⁹ mutations per site per generation was used, whereas 9.5 × 10⁻⁹ was correct. This error affects the interpretation of population-size changes over time and their possible correspondence with kno...

Tree bark is a highly specialized array of tissues that plays important roles in plant protection and development. Bark tissues develop from two lateral meristems; the phellogen (cork cambium) produces the outermost stem–environment barrier called the periderm, while the vascular cambium contributes with phloem tissues. Although bark is diverse in...

To elucidate the origin of shrinkage anisotropy of wood during the drying process, wood from three tree species, Quercus sp., Juglans nigra, and Pometia pinnata, was analyzed using thin cryomicrotome sections and sequential drying on a micro-scale. The data on shrinkage, based on the transverse direction, were calculated using Image Pro Plus softwa...

The objective of this study was to evaluate the ability of one versatile peroxidase and the biocatalytically generated complex Mn(III)-malonate to polymerize coniferyl alcohol (CA) to obtain dehydrogenation polymers (DHPs) and to characterize how closely the structures of the formed DHPs resemble native lignin. Hydrogen peroxide was used as oxidant...

Gaining membrane vesicles from different plant species and tissue types is crucial for membrane studies. Membrane vesicles can be used for further purification of individual membrane types, and, for example, in studies of membrane enzyme activities, transport assays, and in proteomic analysis. Membrane isolation from some species, such as conifers,...

Silver birch (Betula pendula) is a pioneer boreal tree that can be induced to flower within 1 year. Its rapid life cycle, small (440-Mb) genome, and advanced germplasm resources make birch an attractive model for forest biotechnology. We assembled and chromosomally anchored the nuclear genome of an inbred B. pendula individual. Gene duplicates from...

Apart from playing a key role in important biochemical reactions, molecular oxygen (O2) and its by-products also have crucial signaling roles in shaping plant developmental programs and environmental responses. Even under normal conditions, sharp O2 gradients can occur within the plant when cellular O2 demand exceeds supply, especially in dense org...

Laser capture microdissection (LCM) enables precise dissection and collection of individual cell types from complex tissues. When applied to plant cells, and especially to woody tissues, LCM requires extensive optimization to overcome such factors as rigid cell walls, large central vacuoles, intercellular spaces, and technical issues with thickness...

Six potato cultivars grown in Turkey in boron-prone areas and differing in their tolerance towards high boron were studied to reveal whether boron causes oxidative stress. To assess stress level, chlorophyll fluorescence and growth parameters were measured. Oxidative damage was assessed as malondialdehyde level, and antioxidant protection was evalu...

Previous reports have connected non-symbiotic and truncated hemoglobins (Hbs) to metabolism of nitric oxide (NO), an important signalling molecule involved in wood formation. We have studied the capability of poplar (Populus tremula × tremuloides) Hbs PttHb1 and PttTrHb proteins alone or with a flavin-protein reductase to relieve NO cytotoxicity in...

Main conclusion: Externally added coniferyl alcohol at high concentrations reduces the growth of Nicotiana cells and seedlings. Coniferyl alcohol is metabolized by BY-2 cells to several compounds. Coniferyl alcohol (CA) is a common monolignol and a building block of lignin. The toxicity of monolignol alcohols has been stated in the literature, but...

Potato crop production in Turkey ranks on the thirteenth place in the world. Toxicity is a problematic issue for some parts of the Turkish soils. Hence, it is very important to clarify the physiological responses of plants to toxic mineral stress. In this study, two different potato cultivars – Solanum tuberosum cv. Resy and Solanum tuberosum cv. A...

Quantitative and qualitative lignin analyses were carried out on material from the trunks of silver birch (Betula pendula Roth) trees. Two types of material were analyzed. First, whole birch trunk pieces were cryosectioned into cork cambium, non-conductive phloem, the cambial zone (conductive phloem, cambium and differentiating xylem), lignified xy...

Research on the many aspects of the plant cell wall has experienced rejuvenation during the past few years. This is perhaps mainly due to the commercial interest on the chemical components of the cell wall that have potential for industrial use: Cellulose for fibers and together with hemicelluloses for bioethanol, lignin for plastics or biofuel, pe...

The conversion processes of macroalgae for biofuels can be divided into thermochemical (dry) and microbiological (wet) processes. The chemical composition of macroalgae together with the pre-treatment method, conversion conditions, and the characteristics of the microbes involved (wet processes) determine the yield and the properties of the biofuel...

Global gene expression data were analyzed to search for the genes related to oxidative stress response, to examine the differences between hypoxia and anoxia, and to reveal new components of oxygen deprivation response escaped from the previous analyses. Gene Set Z-score (GSZ) was used to report gene ontology (GO) classes that showed significant re...

In this chapter we concentrate on the structure of reaction wood and its functional properties. The fact that a lot more detailed information exists on tension wood rather than on compression wood, this is reflected in the amount of information in this chapter. During reaction wood formation major changes take place in the cell wall polymers and th...

Organellar reactive oxygen species ( ROS ) signalling is a key mechanism that promotes the onset of defensive measures in stress‐exposed plants. The underlying molecular mechanisms and feedback regulation loops, however, still remain poorly understood. Our previous work has shown that a specific regulatory B′γ subunit of protein phosphatase 2A ( PP...

There are no earlier reports with successful isolation of plasma membranes from lignin-forming tissues of conifers. A method to isolate cellular membranes from extracellular lignin-producing tissue-cultured cells and developing xylem of Norway spruce was optimized. Modifications to the homogenization buffer were needed to obtain membranes from thes...

Background: Malondialdehyde (MDA) is a product of lipid peroxidation and a sign of oxidative stress in plants. Therefore, determining the responses of plants to a particular type of stress at a particular time will shed a light on clarifying the stress status of the plants. In this study, we report how MDA levels in potato cultivars changed under t...

Flooding of native and agricultural lands is a major problem on Earth. On the whole world scale, the land area exposed to flooding is more than 17 million km2 annually. Dramatic floods occur in all continents of our planet and result in an estimated damage of more than U.S. $80 billion annually (Global Register of Major Flood Events; www.dartmouth....

Background The hydraulic conductivity of the stem is a major factor limiting the capability of trees to transport water from the soil to transpiring leaves. During drought conditions, the conducting capacity of xylem can be reduced by some conduits being filled with gas, i.e. embolized. In order to understand the dynamics of embolism formation and...

X-ray scattering and microtomography (μCT) are useful techniques to reveal the structure of wood at the nano- and micrometer scales. The nanostructure of xylem in greenhouse-grown 2.5- to 3.5-month-old Populus tremula L. × tremuloides Michx. trees was characterized using wide-angle X-ray scattering (WAXS), and the cellular structure was investigate...

Background: When mineral nutrients are present in excess or in inadequate amounts, their effects can be severe in plants and can be considered as abiotic stress. In this study, we report how hormonal levels in barley cultivars respond to the toxic effect of boron, an essential plant micronutrient. Material and methods: Two different barley (Hordeum...

Flaxseed ( Linum usitatissimum L.) fibers were modified by oxidoreductive and cellulolytic enzymes. The lignin amount and intrinsic plant peroxidase activity was evaluated by histochemical and spectrophotometric assays. Peroxidase activity was not found from bast fibers. The flaxseed fibers were further separated and treated with laccase to conjuga...

The objective of this study was to evaluate the ability of one versatile peroxidase and the biocatalytically generated complex Mn(III)-malonate to polymerize coniferyl alcohol (CA) to obtain dehydrogenated polymers (DHPs) and to characterize the DHPs formed. Hydrogen peroxide was used as oxidant and Mn2+ as mediator. Based on the yields of the poly...

The impact of drying on the structure of the never-dried hardwood cell wall was studied at nanometer level by means of wide- and small-angle X-ray scattering (WAXS, SAXS), and at micrometer level by X-ray microtomography (mu CT). Never-dried silver birch, European aspen and hybrid aspen samples were measured by WAXS in situ during drying in air. Th...

This paper is dedicated to the 35 year jubilee of the founding and the activity of the International Society for Plant Anaerobiosis (ISPA). The role of ISPA members in opening new avenues of research is emphasized. Major developments in the study of plant hypoxic and anoxic stress achieved during subsequent decades are considered. Special attention...

Oxygen deprivation, in line with other stress conditions, is accompanied by reactive oxygen (ROS) and nitrogen species (RNS) formation and is characterised by a set of metabolic changes collectively named as the 'oxidative stress response'. The controversial induction of oxidative metabolism under the lack of oxygen is necessitated by ROS and RNS s...

Plant mitochondria differ from their mammalian counterparts in many respects, which are due to the unique and variable surroundings of plant mitochondria. In green leaves, plant mitochondria are surrounded by ample respiratory substrates and abundant molecular oxygen, both resulting from active photosynthesis, while in roots and bulky rhizomes and...

Class III secretable plant peroxidases occur as a large family of genes in plants with many functions and probable redundancy. In this review we are concentrating on the evidence we have on the catalysis of lignin polymerization by class III plant peroxidases present in the apoplastic space in the xylem of trees. Some evidence exists on the specifi...

This chapter describes the sequence of events leading to lysigenous aerenchyma formation in the roots of wetland and dryland plants. The events start from various stimuli that can induce cells to go through programmed cell death (PCD) in mid-cortical regions of the root: lack of oxygen (hypoxia), nitrogen, phosphorus or sulphur starvation and mecha...

In this chapter, we discuss the metabolic changes relevant for the production of reactive oxygen and nitrogen species (ROS and RNS) in plant tissues during oxygen deprivation. It is notable too, that at times the oxidative damage does not take place during the oxygen deficiency period but only after the restoration of normal oxygen supply to the ti...

The activity of the enzymes of alcoholic and lactic-acid fermentation: pyruvate decarboxylase (PDC, EC 4.1.1.1), alcohol dehydrogenase (ADH, EC 1.1.1.1), lactate dehydrogenase (LDH, EC 1.1.1.27) and the enzymes of malic acid metabolism: phosphoenolpyruvate carboxylase (PEPC, EC 4.1.1.23), NAD-dependent malate dehydrogenase (NAD-MDH, EC 1.1.1.37), a...

Lignification is a cell wall fortifying process which occurs in xylem tissue in a scheduled manner during tissue differentiation. In this review, enzymes and the genes responsible for lignin biosynthesis have been studied with an emphasis on lignin polymerizing class III secretable plant peroxidases. Our aim is to understand the cell and molecular...

Aerenchyma development in Carex rostrata was studied using light and scanning electron microscopy. Specimens were collected at two locations in southern Finland. Examination showed the beginning of aerenchyma development in the cortex of roots at the distance of 30–45 mm from the apex and it was fully developed at 75–90 mm from the apex. First, sch...

The influence of anoxia and hypoxia on dynamic of intracellurar pH and ATP content in rice and wheat root tips was investigated with (31)P-NMR spectroscopy. Both cereals responded to hypoxia similarly, by rapid cytoplasmic acidification (from pH 7.6-7.7 to 7.1), which was followed by slow partial recovery (0.3 units). Anoxia led to a dramatic pH(cy...

Dibenzodioxocin, an 8-ring substructure of lignin identified in the mid-1990's, is known to occur in softwood cell walls especially in the S 3-layers of normal wood. In this study the lignin substructure was immunolocalised in juvenile and mature wood as well as in different degrees of compression wood of Norway spruce (Picea abies (L.) H. Karst.)...

Lignin biosynthesis is a major carbon sink in gymnosperms and woody angiosperms. Many of the enzymes involved are encoded for by several genes, some of which are also related to the biosynthesis of other phenylpropanoids. In this study, we aimed at the identification of those gene family members that are responsible for developmental lignification...

A mathematical computer-aided model CELLOP was constructed in which the desirability functions in a three-dimensional experimental design can be used to find the optimal growing conditions for plant cells. CELLOP is intended for the optimisation of 3 to 6 physical, chemical, or biological variables in the cultivation conditions of plant cell cultur...

Hypoxic pretreatment is known to induce anoxia tolerance in plant species sensitive to oxygen deprivation. However, we still do not have detailed information on changes in cytoplasmic and vacuolar pH (pHcyt and pHvac) in plants under low-oxygen availability (hypoxia) and under anoxia. To investigate this, we have studied the influence of hypoxia an...

Our purpose was to develop a FTIR spectroscopic method to be used to determine the lignin content in a large number of samples and to apply this method studying variation in sapwood and heartwood lignin content between three fast-growing cutting clones grown in three sites. Models were estimated with 18 samples and tested with 6 samples for which t...

It is known that active peroxidase isozymes exist in mature wood of Norway spruce (Picea abies L. Karst.) and that they remain active for years and are found even in the heartwood (in Scots pine), where all cellular activity has ceased. This peroxidase activity was utilised in the impregnation of wood blocks with a natural monolignol, coniferyl alc...

Plant class III peroxidases (POXs) take part in the formation of lignin and maturation of plant cell walls. However, only a few examples of such peroxidases from gymnosperm tree species with highly lignified xylem tracheids have been implicated so far. We report here cDNA cloning of three xylem-expressed class III peroxidase encoding genes from Nor...

We partially purified peroxidase isoform fractions from xylem extracts of a gymnosperm, Norway spruce (Picea abies (L.) Karst.), and an angiosperm, silver birch (Betula pendula Roth.), to determine the participation of xylem-localized peroxidases in polymerization of different types of lignin in vivo. Several peroxidase fractions varying in isoelec...

Carbohydrate and energy metabolism of the flooding- and anoxia-tolerant Iris pseudacorus and the intolerant Iris germanica rhizomes were investigated under experimental anoxic conditions. Rhizomes of I. pseudacorus and I. Germanica were incubated in the absence of oxygen from 0 to 60 and 16 days, respectively. Amounts of glucose, total reducing sug...

Carbohydrate utilization in Iris pseudacorus rhizomes was investigated under natural conditions in the field for a period of one year. The area of study was under flood from mid-December to end of May and wet for the rest of the period of study. Rhizome samples were collected in the wild twice monthly. in order to determine glucose content and amou...

Although oxygen is vital for all aerobic life forms, excessive levels of oxygen free radical production can lead to potentially lethal oxidative reactions. The role of superoxide dismutase is examined as an integral part of the defence against oxidative injury resulting from various physiological stresses.

The steep water is generally aerated in industrial barley malting. However, it is questionable whether oxygen actually reaches the embryo, which remains entrapped under the husk, testa, and pericarp until chitting occurs. The aim of our study was to investigate whether barley embryos experience oxygen deficiency during steeping, and whether various...

The effect of growth rate on weight density and strength properties of three Norway spruce cutting clones growing on three different sites in different geographic locations was stud- ied. The purpose was to follow variation in wood physical and mechanical properties and in quality between fast-growing clones grown in environments differing in nutri...

A specific condensed lignin substructure, dibenzodioxocin, was immunolocalized in differentiating cell walls of Norway spruce ( Picea abies (L.) H. Karsten) and silver birch ( Betula pendula Roth) xylem. A fluorescent probe, Alexa 488 was used as a marker on the dibenzodioxocin-specific secondary antibody. For the detection of this lignin substruct...

The effect of Frankia AiPs1 derived demethyl (C-11) cezomycin, (DC-11C), an antibiotic compound belonging to a class of calcimycins, on calcium transport was studied in wheat root mitochondria. An inhibitory effect in nanomolar concentrations of DC-11C on the rate of Ca2+ uptake by plant mitochondria was detected. Based on the structural similarity...

Summary We examined the relationship between β-glucosi- dase and peroxidase activities and xylem lignification in the stems of Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) Karst.) and silver birch (Betula pendula Roth) during the 1999 growing season. Examination of stem cross sections stained with safranin and Alcian blue for l...

The toxicity and effects on protein synthesis of the phthalate esters diethyl phthalate (DEP) and di(2-ethylhexyl) phthalate (DEHP) was studied in radish seedings (Raphanus sativus cv. Kööpenhaminan tori). Phthalate esters are a class of commercially important compounds used mainly as plasticizers in high molecular-weight polymers such as many plas...

Transcript accumulation and protein activation of superoxide dismutase (SOD) isoenzymes were studied during cold acclimation in potato genotypes of varying degrees of freezing tolerance. In all genotypes studied, 2 days of cold acclimation led to increased SOD activity in concert with improved freezing tolerance. In freezing-tolerant Solanum commer...

The lignification process in mature Norway spruce [ Picea abies (L.) H. Karsten] xylem cell walls was studied using transmission electron microscopy (TEM)-immunogold detection with a polyclonal antibody raised against a specific lignin substructure, dibenzodioxocin. The study reveals for the first time the exact location of this abundant eight-ring...

A spontaneously embryogenic cell line of the coumarin producing angelica [Angelica archangelica (L.) subsp. archangelica] was established via callus formation from seedlings grown from sterilized seeds on semi-solid, hormone-free modified B5 medium. The cell line has retained its embryogenic capacity for 5 years. The highest coumarin production for...

Oxidative stress is induced by a wide range of environmental factors including UV stress, pathogen invasion (hypersensitive reaction), herbicide action and oxygen shortage. Oxygen deprivation stress in plant cells is distinguished by three physiologically different states: transient hypoxia, anoxia and reoxygenation. Generation of reactive oxygen s...

Under stress conditions, mitochondria sense metabolic changes, e.g. in pH, cytoplasmic Ca(2+), energy status, and reactive oxygen species (ROS), and respond by induction of the permeability transition pore (PTP) and by releasing cytochrome c, thus initiating the programmed cell death (PCD) cascade in animal cells. In plant cells, the presence of al...

Hydrogen peroxide (H2O2) was detected cytochemically in plant tissues during anoxia and re‐oxygenation by transmission electron microscopy using its reaction with cerium chloride to produce electron dense precipitates of cerium perhydroxides. Anoxia‐tolerant yellow flag iris (Iris pseudacorus) and rice (Oryza sativa), and anoxia‐intolerant wheat (T...

Hydrogen peroxide (H 2 O 2 ) was detected cytochemically in plant tissues during anoxia and re‐oxygenation by transmission electron microscopy using its reaction with cerium chloride to produce electron dense precipitates of cerium perhydroxides. Anoxia‐tolerant yellow flag iris ( Iris pseudacorus ) and rice ( Oryza sativa ), and anoxia‐intolerant...

The redox potential of the cell, as well as the antioxidant status of the tissue, are considered to be important regulatory constituents in an adaptive response in plants. Here the involvement of active antioxidants ascorbic acid (AA), reduced glutathione (GSH) and α- and β-tocopherols in reactive oxygen species scavenging, and the effect of anoxic...

Peroxidation was studied in anoxically treated plant tissues and quantified as conjugated dienes/trienes in the total lipid fraction and as the production of thiobarbituric acid reactive substances (TBARS). Oxidative stress caused by re-exposure of plants to oxygen led to an increase of conjugated diene/triene formation in rhizomes of Irisgermanica...

Submerging Phaseolus vulgaris cv. Top Crop seed in air-saturated water for 16 h markedly depresses subsequent germination. This is termed soaking injury. The postulate by Norton (1986) that soak-injured seeds merely run out of available energy was investigated. Soaking in air-saturated water reduced the total respiration (VT; in terms of O2 uptake)...

Peroxidase activity and isoenzymes of fresh wood samples of the third shoot of 12-year old trees and from the sapwood, transition zone and heartwood of c. 60-year old stems of Scots pine (Pinus sylvestris L.) were investigated. Wood samples were ground at −30°C, extracted, and the extracts concentrated c. 20-fold for peroxidase activity assays (gua...

Wind and Trees. Edited by CouttsM. P. and GraceJ.. Cambridge: Cambridge University Press. 1995. 485 pp. ISBN 0 521 46037 9. £65 (hardback). - Volume 53 Issue 2 - K. V. Fagerstedt

summaryProteolytic and cellulolytic activities were studied in the ectomycorrhizal fungi Amanita regalis (Fr.) Maire, Paxillus involutus (Batsch ex Fr.) Fr. and Suillus bovinus (L. ex Fr.) O. Kuntze and the necrotrophic root pathogenic fungus Heterobasidion annosum (Fr.) Bref. using plate assays, native gel electrophoresis and substrate gel replica...

The perennating organ, the rhizome, was chosen for examination of response to anoxia in the species Iris pseudacorus L., Iris germanica L. var Quechei, and Glyceria maxima (Hartm.) Holmberg. These monocots are known to differ in their tolerance of anoxia. Intact rhizomes were subjected to periods of prolonged anoxia of up to 28 days and superoxide...

Three barley cultivars, Hordeum vulgare L. cv. Kustaa, Hankkija-673 and Pokko were tested for their anoxia and. flooding tolerance to observe whether anoxia tolerance is related to flooding tolerance and whether the cultivars differ in their anoxia and flooding tolerance. Three-day-old seedlings were incubated under anoxia at +5 degrees C for 10-20...

The Finnish barley cultivar (Hordeum vulgare L, cv. Hankkija-673) was grown in solution culture for periods of one and two months. The one month old plants had seminal roots, whereas the two month old plants grew adventitious roots from the lower nodes. The roots were tested for ADH activity during aeration, during 3 d of hypoxic treatment (brought...

Flooded barley seedlings rapidly developed chlorosis; in contrast the chlorophyll content of the oldest leaves of C. rostrata increased in both flooded and control plants. -from Author

Metabolomics 2010. Breakthroughs in plant, microbial and human biology, clinical and nutritional research, and biomarker discovery. Amsterdam, The Netherlands, 27 June - 1 July 2010, 146

10th ISPA (International Society for Plant Anaerobiosis) Conference, Volterra, Italy, 20 - 25 June 2010