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Author

Laura Jaakola

Other affiliations: University of Oulu
Bio: Laura Jaakola is an academic researcher from University of Tromsø. The author has contributed to research in topics: Bilberry & Vaccinium myrtillus. The author has an hindex of 29, co-authored 72 publications receiving 4034 citations. Previous affiliations of Laura Jaakola include University of Oulu.


Papers
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Journal ArticleDOI
TL;DR: A simplified model for the different regulatory networks involved with anthocyanin production in fruit is proposed and shows clear links between the developmental regulatory network and the specific regulators of anthcyanin biosynthesis during fruit ripening.

789 citations

Journal ArticleDOI
TL;DR: A correlation between anthocyanin accumulation and expression of the flavonoid pathway genes during the ripening of berries is demonstrated and models for the connection between flavonol and anthOCyanin syntheses in fruit tissues are presented.
Abstract: The production of anthocyanins in fruit tissues is highly controlled at the developmental level. We have studied the expression of flavonoid biosynthesis genes during the development of bilberry (Vaccinium myrtillus) fruit in relation to the accumulation of anthocyanins, proanthocyanidins, and flavonols in wild berries and in color mutants of bilberry. The cDNA fragments of five genes from the flavonoid pathway, phenylalanine ammonia-lyase, chalcone synthase, flavanone 3-hydroxylase, dihydroflavonol 4-reductase, and anthocyanidin synthase, were isolated from bilberry using the polymerase chain reaction technique, sequenced, and labeled with a digoxigenin-dUTP label. These homologous probes were used for determining the expression of the flavonoid pathway genes in bilberries. The contents of anthocyanins, proanthocyanidins, and flavonols in ripening bilberries were analyzed with high-performance liquid chromatography-diode array detector and were identified using a mass spectrometry interface. Our results demonstrate a correlation between anthocyanin accumulation and expression of the flavonoid pathway genes during the ripening of berries. At the early stages of berry development, procyanidins and quercetin were the major flavonoids, but the levels decreased dramatically during the progress of ripening. During the later stages of ripening, the content of anthocyanins increased strongly and they were the major flavonoids in the ripe berry. The expression of flavonoid pathway genes in the color mutants of bilberry was reduced. A connection between flavonol and anthocyanin synthesis in bilberry was detected in this study and also in previous data collected from flavonol and anthocyanin analyses from other fruits. In accordance with this, models for the connection between flavonol and anthocyanin syntheses in fruit tissues are presented.

398 citations

Journal ArticleDOI
TL;DR: This method is a modification of the one described for pine trees, and yields high-quality RNA suitable for cDNA based methodologies, and is applicable for a variety of plant tissues.
Abstract: A simple and efficient method is described for isolating high quality RNA from bilberry fruit. The procedure is based on the use of hexadecyltrimethyl ammonium bromide (CTAB), polyvinylpyrrolidone (PVP), and β-mercaptoethanol in an extraction buffer in order to eliminate the polysaccharides and prevent the oxidation of phenolic compounds. This method is a modification of the one described for pine trees, and yields high-quality RNA suitable for cDNA based methodologies. This method is applicable for a variety of plant tissues.

365 citations

Journal ArticleDOI
TL;DR: An overview of the currently known mechanisms of the light-controlled flavonoid accumulation is provided and R2R3 MYB transcription factors are known to regulate by differential expression the biosynthesis of distinct flavonoids in response to specific light wavelengths.
Abstract: Light is one of the most important environmental factors affecting flavonoid biosynthesis in plants. The absolute dependency of light to the plant development has driven evolvement of sophisticated mechanisms to sense and transduce multiple aspects of the light signal. Light effects can be categorized in photoperiod (duration), intensity (quantity), direction and quality (wavelength) including UV-light. Recently, new information has been achieved on the regulation of light-controlled flavonoid biosynthesis in fruits, in which flavonoids have a major contribution on quality. This review focuses on the effects of the different light conditions on the control of flavonoid biosynthesis in fruit producing plants. An overview of the currently known mechanisms of the light-controlled flavonoid accumulation is provided. R2R3 MYB transcription factors are known to regulate by differential expression the biosynthesis of distinct flavonoids in response to specific light wavelengths. Despite recent advances, many gaps remain to be understood in the mechanisms of the transduction pathway of light-controlled flavonoid biosynthesis. A better knowledge on these regulatory mechanisms is likely to be useful for breeding programs aiming to modify fruit flavonoid pattern.

330 citations

Journal ArticleDOI
TL;DR: Current knowledge about the effect of light intensity, photoperiod and temperature on the gene-environment interaction related to flavonoid biosynthesis in plants is focused on.
Abstract: The growth conditions in different latitudes vary markedly with season, day length, light quality and temperature. Many plant species have adapted well to the distinct environments through different strategies, one of which is the production of additional secondary metabolites. Flavonoids are a widely spread group of plant secondary metabolites that are involved in many crucial functions of plants. Our understanding of the biosynthesis, occurrence and function of flavonoids has increased rapidly in recent decades. Numerous studies have been published on the influence of environmental factors on the biosynthesis of flavonoids. However, extensive long-term studies that examine the effect of the characteristics of northern climates on flavonoid biosynthesis are still scarce. This review focuses on the current knowledge about the effect of light intensity, photoperiod and temperature on the gene-environment interaction related to flavonoid biosynthesis in plants.

320 citations


Cited by
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Journal ArticleDOI
TL;DR: This review addresses the concept of endophytism, considering the latest insights into evolution, plant ecosystem functioning, and multipartite interactions.
Abstract: All plants are inhabited internally by diverse microbial communities comprising bacterial, archaeal, fungal, and protistic taxa. These microorganisms showing endophytic lifestyles play crucial roles in plant development, growth, fitness, and diversification. The increasing awareness of and information on endophytes provide insight into the complexity of the plant microbiome. The nature of plant-endophyte interactions ranges from mutualism to pathogenicity. This depends on a set of abiotic and biotic factors, including the genotypes of plants and microbes, environmental conditions, and the dynamic network of interactions within the plant biome. In this review, we address the concept of endophytism, considering the latest insights into evolution, plant ecosystem functioning, and multipartite interactions.

1,677 citations

Journal ArticleDOI
TL;DR: Scientific studies show that anthocyanidins and Anthocyanins possess antioxidative and antimicrobial activities, improve visual and neurological health, and protect against various non-communicable diseases.
Abstract: Anthocyanins are colored water-soluble pigments belonging to the phenolic group. The pigments are in glycosylated forms. Anthocyanins responsible for the colors, red, purple, and blue, are in fruits and vegetables. Berries, currants, grapes, and some tropical fruits have high anthocyanins content. Red to purplish blue-colored leafy vegetables, grains, roots, and tubers are the edible vegetables that contain a high level of anthocyanins. Among the anthocyanin pigments, cyanidin-3-glucoside is the major anthocyanin found in most of the plants. The colored anthocyanin pigments have been traditionally used as a natural food colorant. The color and stability of these pigments are influenced by pH, light, temperature, and structure. In acidic condition, anthocyanins appear as red but turn blue when the pH increases. Chromatography has been largely applied in extraction, separation, and quantification of anthocyanins. Besides the use of anthocyanidins and anthocyanins as natural dyes, these colored pigments are potential pharmaceutical ingredients that give various beneficial health effects. Scientific studies, such as cell culture studies, animal models, and human clinical trials, show that anthocyanidins and anthocyanins possess antioxidative and antimicrobial activities, improve visual and neurological health, and protect against various non-communicable diseases. These studies confer the health effects of anthocyanidins and anthocyanins, which are due to their potent antioxidant properties. Different mechanisms and pathways are involved in the protective effects, including free-radical scavenging pathway, cyclooxygenase pathway, mitogen-activated protein kinase pathway, and inflammatory cytokines signaling. Therefore, this review focuses on the role of anthocyanidins and anthocyanins as natural food colorants and their nutraceutical properties for health. Abbreviations: CVD: Cardiovascular disease VEGF: Vascular endothelial growth factor.

1,411 citations

Journal ArticleDOI
TL;DR: Recent advances in the characterization of the underlying regulatory mechanisms of flavonoid biosynthesis are reviewed, with a special focus on the MBW (MYB-bHLH-WDR) protein complexes.

1,032 citations

Journal ArticleDOI
TL;DR: Molecular genetic approaches are leading to an understanding of the regulatory genes that control proanthocyanidin biosynthesis, and this information, together with increased knowledge of the enzymes specific for the pathway, will facilitate the genetic engineering of plants for introduction of value-added nutraceutical and forage quality traits.
Abstract: Proanthocyanidins are oligomeric and polymeric end products of the flavonoid biosynthetic pathway. They are present in the fruits, bark, leaves and seeds of many plants, where they provide protection against predation. At the same time they give flavor and astringency to beverages such as wine, fruit juices and teas, and are increasingly recognized as having beneficial effects on human health. The presence of proanthocyanidins is also a major quality factor for forage crops. The past 2 years have seen important breakthroughs in our understanding of the biosynthesis of the building blocks of proanthocyanidins, the flavan-3-ols (+)-catechin and (-)-epicatechin. However, virtually nothing is known about the ways in which these units are assembled into the corresponding oligomers in vivo. Molecular genetic approaches are leading to an understanding of the regulatory genes that control proanthocyanidin biosynthesis, and this information, together with increased knowledge of the enzymes specific for the pathway, will facilitate the genetic engineering of plants for introduction of value-added nutraceutical and forage quality traits.

1,009 citations

Journal ArticleDOI
26 May 2011-PLOS ONE
TL;DR: The process of selecting and refining a plant barcode is reviewed; the factors which influence the discriminatory power of the approach are evaluated; some early applications of plant barcoding are described and summarise major emerging projects; and outline tool development that will be necessary for plant DNA barcode to advance.
Abstract: The main aim of DNA barcoding is to establish a shared community resource of DNA sequences that can be used for organismal identification and taxonomic clarification. This approach was successfully pioneered in animals using a portion of the cytochrome oxidase 1 (CO1) mitochondrial gene. In plants, establishing a standardized DNA barcoding system has been more challenging. In this paper, we review the process of selecting and refining a plant barcode; evaluate the factors which influence the discriminatory power of the approach; describe some early applications of plant barcoding and summarise major emerging projects; and outline tool development that will be necessary for plant DNA barcoding to advance.

993 citations