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Andrzej Bajguz - One of the best experts on this subject based on the ideXlab platform.

  • Brassinolide Enhances the Level of Brassinosteroids, Protein, Pigments, and Monosaccharides in Wolffia arrhiza Treated with Brassinazole
    'MDPI AG', 2021
    Co-Authors: Magdalena Chmur, Andrzej Bajguz
    Abstract:

    Brassinolide (BL) represents brassinosteroids (BRs)—a group of phytohormones that are essential for plant growth and development. Brassinazole (Brz) is as a synthetic inhibitor of BRs’ biosynthesis. In the present study, the responses of Wolffia arrhiza to the treatment with BL, Brz, and the combination of BL with Brz were analyzed. The analysis of BRs and Brz was performed using LC-MS/MS. The photosynthetic pigments (chlorophylls, carotenes, and xanthophylls) levels were determined using HPLC, but protein and monosaccharides level using spectrophotometric methods. The obtained results indicated that BL and Brz influence W. arrhiza cultures in a concentration-dependent manner. The most stimulatory effects on the growth, level of BRs (BL, 24-epibrassinolide, 28-homobrassinolide, 28-norbrassinolide, catasterone, Castasterone, 24-epiCastasterone, typhasterol, and 6-deoxytyphasterol), and the content of pigments, protein, and monosaccharides, were observed in plants treated with 0.1 µM BL. Whereas the application of 1 µM and 10 µM Brz caused a significant decrease in duckweed weight and level of targeted compounds. Application of BL caused the mitigation of the Brz inhibitory effect and enhanced the BR level in duckweed treated with Brz. The level of BRs was reported for the first time in duckweed treated with BL and/or Brz

  • Effect of Cadmium on the Level of Isoprenoid-Derived Phytohormones in Duckweed Wolffia arrhiza
    Journal of Plant Growth Regulation, 2020
    Co-Authors: Magdalena Chmur, Andrzej Bajguz, Alicja Piotrowska-niczyporuk
    Abstract:

    Wolffia arrhiza (L.) Horkel ex Wimm. is an aquatic plant belonging to the Lemnaceae family. It does not have leaves, stems, and roots, flowers rarely occur, while body size can reach 1 mm of width and 1.3 mm of length. The present study demonstrates the endogenous level of isoprenoid-derived phytohormones and their changes under the influence of different cadmium (Cd) concentrations (0.1, 1, 10, and 100 µM). A liquid chromatography quadrupole-time-of-flight mass spectrometry analysis indicated the presence of abscisic acid, eight brassinosteroids (6-deoxoCastasterone, 6-deoxotyphasterol, cathasterone, typhasterol, Castasterone, 24-epiCastasterone, brassinolide, and 28-homobrassinolide), seven free bases of cytokinins [ trans -zeatin ( t Z), cis -zeatin ( c Z), dihydrozeatin (DHZ), N ^6-isopentenyladenine, N ^6-isopentenyladenosine, ortho -topolin, and meta -topolin], eight conjugates of cytokinins ( t Z riboside, t Z-9-glucoside, t Z-7-glucoside, t Z- O -glucoside riboside, c Z-9-glucoside, DHZ riboside, DHZ- O -glucoside, and N ^6-isopentenyladenosine-7-glucoside) and gibberellic acid (GA_3) in this duckweed. The level of phytohormones in plants treated with Cd has changed, e.g., the ABA level increased while GA_3 decreased. Whereas the amount of BRs and CKs was different in Cd dose-dependent manner. Besides, it is worth noting that the distribution of 25 various phytohormones in the Wolffia arrhiza is reported for the first time.

  • interactive effect of brassinosteroids and cytokinins on growth chlorophyll monosaccharide and protein content in the green alga chlorella vulgaris trebouxiophyceae
    Plant Physiology and Biochemistry, 2014
    Co-Authors: Andrzej Bajguz, Alicja Piotrowskaniczyporuk
    Abstract:

    Interaction between brassinosteroids (BRs) (brassinolide, BL; 24-epibrassinolide, 24-epiBL; 28-homobrassinolide, 28-homoBL; Castasterone, CS; 24-epiCastasterone, 24-epiCS; 28-homoCastasterone, 28-homoCS) and adenine- (trans-zeatin, tZ; kinetin, Kin) as well as phenylurea-type (1,3-diphenylurea, DPU) cytokinins (CKs) in the regulation of cell number, phytohormone level and the content of chlorophyll, monosaccharide and protein in unicellular green alga Chlorella vulgaris (Trebouxiophyceae) were examined. Chlorella vulgaris exhibited sensitivity to CKs in the following order of their stimulating properties: 10 nM tZ > 100 nM Kin >1 μM DPU. Exogenously applied BRs possessed the highest biological activity in algal cells at concentration of 10 nM. Among the BRs, BL was characterized by the highest activity, while 28-homoCS - by the lowest. The considerable increase in the level of all endogenous BRs by 27–46% was observed in C. vulgaris culture treated with exogenous 10 nM tZ. It can be speculated that CKs may stimulate BR activity in C. vulgaris by inducing the accumulation of endogenous BRs. CKs interacted synergistically with BRs increasing the number of cells and endogenous accumulation of proteins, chlorophylls and monosaccharides in C. vulgaris. The highest stimulation of algal growth and the contents of analyzed biochemical parameters were observed for BL applied in combination with tZ, whereas the lowest in the culture treated with both 28-homoCS and DPU. However, regardless of the applied mixture of BRs with CKs, the considerable increase in cell number and the metabolite accumulation was found above the level obtained in cultures treated with any single phytohormone in unicellular green alga C. vulgaris.

  • synergistic effect of auxins and brassinosteroids on the growth and regulation of metabolite content in the green alga chlorella vulgaris trebouxiophyceae
    Plant Physiology and Biochemistry, 2013
    Co-Authors: Andrzej Bajguz, Alicja Piotrowskaniczyporuk
    Abstract:

    The relationships between brassinosteroids (BRs) (brassinolide, BL; 24-epiBL; 28-homoBL; Castasterone, CS; 24-epiCS; 28-homoCS) and auxins (indole-3-acetic acid, IAA; indole-3-butyric acid, IBA; indole-3-propionic acid, IPA) in the regulation of cell number, phytohormone level and metabolism in green alga Chlorella vulgaris were investigated. Exogenously applied auxins had the highest biological activity in algal cells at 50 μM. Among the auxins, IAA was characterized by the highest activity, while IBA - by the lowest. BRs at 0.01 μM were characterized by the highest biological activity in relation to auxin-treated and untreated cultures of C. vulgaris. The application of 50 μM IAA stimulated the level of all detected endogenous BRs in C. vulgaris cells. The stimulatory effect of BRs in green algae was arranged in the following order: BL > 24-epiBL > 28-homoBL > CS > 24-epiCS > 28-homoCS. Auxins cooperated synergistically with BRs stimulating algal cell proliferation and endogenous accumulation of proteins, chlorophylls and monosaccharides in C. vulgaris. The highest stimulation of algal growth and the contents of analyzed biochemical parameters were observed for the mixture of BL with IAA, whereas the lowest in the culture treated with both 28-homoCS and IBA. However, regardless of the applied mixture of BRs with auxins, the considerable increase in cell number and the metabolite accumulation was found above the level obtained in cultures treated with any single phytohormone. Obtained results confirm that both groups of plant hormones cooperate synergistically in the control of growth and metabolism of unicellular green alga C. vulgaris.

  • isolation and characterization of brassinosteroids from algal cultures of chlorella vulgaris beijerinck trebouxiophyceae
    Journal of Plant Physiology, 2009
    Co-Authors: Andrzej Bajguz
    Abstract:

    The brassinosteroids (BRs) occur ubiquitously in the plant kingdom. The occurrence of BRs has been demonstrated in almost every part of higher plants, such as pollen, flower buds, fruits, seeds, vascular cambium, leaves, shoots and roots. In this study, BRs were isolated and identified in the culture of wild-type Chlorella vulgaris. Seven BRs, including teasterone, typhasterol, 6-deoxoteasterone, 6-deoxotyphasterol, 6-deoxoCastasterone, Castasterone and brassinolide, were identified by GC-MS. All compounds belong to the BR biosynthetic pathway. The results suggest that early and late C6 oxidation pathways are operating in C. vulgaris. This study represents the first isolation of BRs from C. vulgaris cultures.

Suguru Takatsuto - One of the best experts on this subject based on the ideXlab platform.

  • Co-Regulation of Brassinosteroid Biosynthesis-Related Genes During Xylem Cell Differentiation
    2016
    Co-Authors: Ryo Yamamoto, Kuninori Iwamoto, Taku Demura, Shozo Fujioka, Suguru Takatsuto, Shigeo Yoshida, Hiroo Fukuda
    Abstract:

    To understand the regulatory mechanisms of brassino-steroid (BR) biosynthesis in specific plant developmental processes, we first investigated the accumulation profiles of BRs and sterols in xylem differentiation in a Zinnia culture. The amounts of many substances in the late C28 sterol biosynthetic pathway to campesterol (CR), such as episterol and 24-methylenecholesterol, as well as those in the BR-specific biosynthetic pathway from CR to brassinolide (BL), were elevated in close association with tracheary element differentiation. Among them, 6-deoxotyphasterol (6-deoxoTY) accumulated to unusually high levels within cells cultured in tracheary element-inductive medium, while Castasterone (CS) was not elevated either within or outside cells. To identify the molecular basis of this co-up-regulation of BRs and C28 sterols, we isolated Zinnia genes for the ke

  • Rapid Report Identification of Castasterone, 6-DeoxoCastasterone, Typhasterol and 6-DeoxotyphasteroI from the Shoots of Arabidopsis thaliana
    2016
    Co-Authors: Yong-hwa Choi, Suguru Takatsuto, Takao Yokota, Joanne Chory, Akira Sakurai
    Abstract:

    Endogenous brassinosteroids in the shoots of Arabi-dopsis thaliana were investigated. Castasterone, 6-deoxo-Castasterone, typhasterol and 6-deoxotyphasterol were identified by GC-MS. The co-occurrence of 6-deoxo-bras-sinosteroids and 6-oxo-brassinosteroids suggests that there are both early and late C6-oxidation pathways of brassino-steroids in A. thaliana. Key words: Arabidopsis thaliana — Early C6-oxidation pathway — Endogenous brassinosteroids — Late C6-oxida-tion pathway — Shoot. We have studied biosynthesis of brassinosteroids, steroidal plant hormones, using cultured cells of Catharan-thus roseus, and the biosynthetic pathway from plant sterols to brassinolide has been elucidated (Yokota et al. 1990, Suzuki et al. 1993, 1994a, b, 1995a, Fujioka et al

  • Arabidopsis Brassinosteroid-Insensitive dwarf12 Mutants Are Semidominant and Defective in a Glycogen Synthase
    2015
    Co-Authors: Kinase -like Kinase, Shozo Fujioka, Suguru Takatsuto, Shigeo Yoshida, Sunghwa Choe, Kenneth A Feldmann, Robert J. Schmitz, Mi-ok Lee, Frans E. Tax
    Abstract:

    Mutants defective in the biosynthesis or signaling of brassinosteroids (BRs), plant steroid hormones, display dwarfism. Loss-of-function mutants for the gene encoding the plasma membrane-located BR receptor BRI1 are resistant to exogenous application of BRs, and characterization of this protein has contributed significantly to the understanding of BR signaling. We have isolated two new BR-insensitive mutants (dwarf12-1D and dwf12-2D) after screening Arabidopsis ethyl methane-sulfonate mutant populations. dwf12 mutants displayed the characteristic morphology of previously reported BR dwarfs including short stature, short round leaves, infertility, and abnormal de-etiolation. In addition, dwf12 mutants exhibited several unique phenotypes, including severe downward curling of the leaves. Genetic analysis indicates that the two mutations are semidominant in that heterozygous plants show a semidwarf phenotype whose height is intermediate between wild-type and homozygous mutant plants. Unlike BR biosynthetic mutants, dwf12 plants were not rescued by high doses of exogenously applied BRs. Like bri1 mutants, dwf12 plants accumulated Castasterone and brassinolide, 43- and 15-fold higher, respectively, providing further evidence that DWF12 is a component of the BR signaling pathway that includes BRI1. Map-based cloning of the DWF12 gene revealed that DWF12 belongs to a member of the glycogen synthase kinase 3 family. Unlike human glycogen synthase kinase 3, DWF12 lacks the conserved serine-9 residue in the auto-inhibitory N terminus. In addition, dwf12-1D and dwf12-2D encode changes in consecutive glutamate residues in a highl

  • Arabidopsis CYP85A2, a Cytochrome P450, Mediates the Baeyer-Villiger Oxidation of Castasterone to Brassinolide
    2013
    Co-Authors: In Brassinosteroid Biosynthesis, Suguru Takatsuto, Seong-ki Kima
    Abstract:

    The conversion of Castasterone (CS) to brassinolide (BL), a Baeyer-Villiger oxidation, represents the final and rate-limiting step in the biosynthesis of BL in plants. Heterologously expressed Arabidopsis thaliana CYP85A2 in yeast mediated the conversion of CS to BL as well as the C-6 oxidation of brassinosteroids (BRs). This indicated that CYP85A2 is a bifunctional enzyme that possesses BR C-6 oxidase and BL synthase activity. CYP85A2 is thus a cytochrome P450 that mediates Baeyer-Villiger oxidation in plants. Biochemical, physiological, and molecular genetic analyses of Arabidopsis CYP85A2 loss-of-function and overexpression lines demonstrated that CS has to be a bioactive BR that controls the overall growth and development of Arabidopsis plants. Mutant studies also revealed that BL may not always be necessary for normal growth and development but that Arabidopsis plants acquire great benefit in terms of growth and development in the presence of BL

  • the ugt73c5 of arabidopsis thaliana glucosylates brassinosteroids
    Proceedings of the National Academy of Sciences of the United States of America, 2005
    Co-Authors: Brigitte Poppenberger, Shozo Fujioka, Hideharu Seto, Suguru Takatsuto, Gerhard Adam, Kazuo Soeno, Gilu George, Fabian E Vaistij, Sayoko Hiranuma, Shigeo Yoshida
    Abstract:

    Steroid hormones are essential for development, and the precise control of their homeostasis is a prerequisite for normal growth. UDP-glycosyltransferases (UGTs) are considered to play an important regulatory role in the activity of steroids in mammals and insects. This study provides an indication that a UGT accepting plant steroids as substrates functions in brassinosteroid (BR) homeostasis. The UGT73C5 of Arabidopsis thaliana catalyses 23-O-glucosylation of the BRs brassinolide (BL) and Castasterone. Transgenic plants overexpressing UGT73C5 displayed BR-deficient phenotypes and contained reduced amounts of BRs. The phenotype, which was already apparent in seedlings, could be rescued by application of BR. In feeding experiments with BL, wild-type seedlings converted BL to the 23-O-glucoside; in the transgenic lines silenced in UGT73C5 expression, no 23-O-glucoside was detected, implying that this UGT is the only enzyme that catalyzes BL-23-O-glucosylation in seedlings. Plant lines in which UGT73C5 expression was altered also displayed hypocotyl phenotypes previously described for seedlings in which BR inactivation by hydroxylation was changed. These data support the hypothesis that 23-O-glucosylation of BL is a function of UGT73C5 in planta, and that glucosylation regulates BR activity.

Anna Janeczko - One of the best experts on this subject based on the ideXlab platform.

  • a reverse genetics mutational analysis of the barley hvdwarf gene results in identification of a series of alleles and mutants with short stature of various degree and disturbance in br biosynthesis allowing a new insight into the process
    International Journal of Molecular Sciences, 2016
    Co-Authors: Damian Gruszka, Malgorzata Gorniak, Ewelina Glodowska, Ewa Wierus, Jana Oklestkova, Anna Janeczko, Miroslaw Maluszynski, Iwona Szarejko
    Abstract:

    Brassinosteroids (BRs) are plant steroid hormones, regulating a broad range of physiological processes. The largest amount of data related with BR biosynthesis has been gathered in Arabidopsis thaliana, however understanding of this process is far less elucidated in monocot crops. Up to now, only four barley genes implicated in BR biosynthesis have been identified. Two of them, HvDWARF and HvBRD, encode BR-6-oxidases catalyzing biosynthesis of Castasterone, but their relation is not yet understood. In the present study, the identification of the HvDWARF genomic sequence, its mutational and functional analysis and characterization of new mutants are reported. Various types of mutations located in different positions within functional domains were identified and characterized. Analysis of their impact on phenotype of the mutants was performed. The identified homozygous mutants show reduced height of various degree and disrupted skotomorphogenesis. Mutational analysis of the HvDWARF gene with the “reverse genetics” approach allowed for its detailed functional analysis at the level of protein functional domains. The HvDWARF gene function and mutants’ phenotypes were also validated by measurement of endogenous BR concentration. These results allowed a new insight into the BR biosynthesis in barley.

  • brassinosteroids increase winter survival of winter rye secale cereale l by affecting photosynthetic capacity and carbohydrate metabolism during the cold acclimation process
    Plant Growth Regulation, 2016
    Co-Authors: Ewa Pociecha, Jana Oklestkova, Michal Dziurka, Anna Janeczko
    Abstract:

    The aim of the study was to verify the hypothesis that brassinosteroids would modify the cold acclimation process through the stimulation of photosynthesis and carbohydrate metabolism, and would consequently cause an increase in the plant’s capacity for winter survival. Seedlings of two winter rye cultivars (winter-resistant and moderately winter-resistant types) were sprayed with 24-epibrassinolide (EBR) and then subjected to cold acclimation at 4 °C. The foliar hormone application was studied for its effects on two components of winter resistance: tolerance to frost; and resistance to snow mould. These were examined after medium (3 weeks) and long (6 weeks) terms of cold acclimation. Additionally, as a control group, the level of endogenous brassinosteroids was measured in non-treated plants. The maximum acquired snow mould resistance was observed in the EBR-treated plants after 3 weeks of cold acclimation, while the maximum frost tolerance was recorded after 6 weeks of cold acclimation, as compared with control. In the winter-resistant cultivars, the EBR-induced snow mould resistance coincided with a lower photosynthetic efficiency and a lack of change in their Rubisco activity and level of total soluble carbohydrates. The elevated EBR-induced frost tolerance in the winter-resistant cultivars was associated with a carbohydrate metabolism that promoted a decrease in the monosaccharides of the leaves that stimulate photosynthetic efficiency and Rubisco activity. For both cultivars, the control plants developed frost tolerance between the third and sixth week of cold acclimation. However, the winter-resistant cultivar was characterised by a constant Castasterone (CS) level, while the moderately winter-resistant one experienced a sharp increase in its endogenous CS after 3 weeks, and then after 6 weeks of cold acclimation.

  • brassinosteroids increase winter survival of winter rye secale cereale l by affecting photosynthetic capacity and carbohydrate metabolism during the cold acclimation process
    Plant Growth Regulation, 2016
    Co-Authors: Ewa Pociecha, Jana Oklestkova, Michal Dziurka, Anna Janeczko
    Abstract:

    The aim of the study was to verify the hypothesis that brassinosteroids would modify the cold acclimation process through the stimulation of photosynthesis and carbohydrate metabolism, and would consequently cause an increase in the plant’s capacity for winter survival. Seedlings of two winter rye cultivars (winter-resistant and moderately winter-resistant types) were sprayed with 24-epibrassinolide (EBR) and then subjected to cold acclimation at 4 °C. The foliar hormone application was studied for its effects on two components of winter resistance: tolerance to frost; and resistance to snow mould. These were examined after medium (3 weeks) and long (6 weeks) terms of cold acclimation. Additionally, as a control group, the level of endogenous brassinosteroids was measured in non-treated plants. The maximum acquired snow mould resistance was observed in the EBR-treated plants after 3 weeks of cold acclimation, while the maximum frost tolerance was recorded after 6 weeks of cold acclimation, as compared with control. In the winter-resistant cultivars, the EBR-induced snow mould resistance coincided with a lower photosynthetic efficiency and a lack of change in their Rubisco activity and level of total soluble carbohydrates. The elevated EBR-induced frost tolerance in the winter-resistant cultivars was associated with a carbohydrate metabolism that promoted a decrease in the monosaccharides of the leaves that stimulate photosynthetic efficiency and Rubisco activity. For both cultivars, the control plants developed frost tolerance between the third and sixth week of cold acclimation. However, the winter-resistant cultivar was characterised by a constant Castasterone (CS) level, while the moderately winter-resistant one experienced a sharp increase in its endogenous CS after 3 weeks, and then after 6 weeks of cold acclimation.

  • Barley brassinosteroid mutants provide an insight into phytohormonal homeostasis in plant reaction to drought stress
    Frontiers Media S.A., 2016
    Co-Authors: Damian Gruszka, Jana Oklestkova, Anna Janeczko, Ewa Pociecha, Michal Dziurka, Iwona Szarejko
    Abstract:

    Brassinosteroids (BRs) are a class of steroid phytohormones, which regulate various processes of morphogenesis and physiology – from seed development to regulation of flowering and senescence. An accumulating body of evidence indicates that BRs take part in regulation of physiological reactions to various stress conditions, including drought. Many of the physiological functions of BRs are regulated by a complicated, and not fully elucidated network of interactions with metabolic pathways of other phytohormones. Therefore, the aim of this study was to characterize phytohormonal homeostasis in barley (Hordeum vulgare) in reaction to drought and validate role of BRs in regulation of this process. Material of this study included the barley cultivar ‘Bowman’ and five Near-Isogenic Lines (NILs) representing characterized semi-dwarf mutants of several genes encoding enzymes participating in BR biosynthesis and signaling. Analysis of endogenous BRs concentrations in these NILs confirmed that their phenotypes result from abnormalities in BR metabolism. In general, concentrations of eighteen compounds, representing various classes of phytohormones, including brassinosteroids, auxins, cytokinins, gibberellins, abscisic acid, salicylic acid and jasmonic acid were analyzed under control and drought conditions in the ‘Bowman’ cultivar and the BR-deficient NILs. Drought induced a significant increase in accumulation of the biologically active form of BRs – Castasterone in all analyzed genotypes. Another biologically active form of BRs – 24-epi-brassinolide - was identified in one, BR-insensitive NIL under normal condition, but its accumulation was drought-induced in all analyzed genotypes. Analysis of concentration profiles of several compounds representing gibberellins allowed an insight into the BR-dependent regulation of gibberellin biosynthesis. The concentration of the gibberellic acid GA7 was significantly lower in all NILs when compared with the ‘Bowman’ cultivar, indicating that GA7 biosynthesis represents an enzymatic step at which the stimulating effect of BRs on gibberellin biosynthesis occurs. Moreover, the accumulation of GA7 is significantly induced by drought in all the genotypes. Biosynthesis of jasmonic acid is also a BR-dependent process, as all the NILs accumulated much lower concentrations of this hormone when compared with the ‘Bowman’ cultivar under normal condition, however the accumulation of jasmonic acid, abscisic acid and salicylic acid were significantly stimulated by drought

  • Wpływ brasinosteroidów na plonowanie soi w Polsce
    2011
    Co-Authors: Anna Janeczko, Jolanta Biesaga-kościelniak, Michał Dziurka, Jana Oklešťková, Maciej Kocurek, Grażyna Szarek-Łukaszewska, Zbigniew Janeczko, J A
    Abstract:

    Abstract. In the present study, we evaluated the effects of exogenously applied 24--epibrassinolide -one of the brassinosteroids -on the seed yield, seed chemical composition (content of soluble proteins, phytoestrogens, carbohydrates, minerals) and resistance to drought of soybean cultivated in Poland (cv. Aldana and Augusta). Quantitative and qualitative analysis of brassinosteroid content was made in seeds of plants treated with 24-epibrassinolide. Experiments were performed in the field and in greenhouse. Brassinosteroid was applied via presowing seed soaking (0,25 mg·dm -3 ) and spraying of plants (1 mg·dm -3 ). 24-epibrassinolide affected the increase of the weight of seeds per one plant (27-73%) depending on the cultivar as well as growth conditions (occurrence or lack of drought factor at the stage of seed setting). In the seeds, 24--epibrassinolide did not change content of proteins or soluble carbohydrates, but increased phytoestrogen genistein content in cultivar Aldana and decreased level of potassium in cultivar Augusta and calcium level in cultivar Aldana. In soybean seeds, the presence of brassinolide and Castasterone was found. 24-epibrassinolide applied exogenously to plants was not accumulated in newly formed seeds. In drought-stressed soybean brassinosteroid showed protective effect on net photosynthesis and photosystem II efficiency

Alicja Piotrowskaniczyporuk - One of the best experts on this subject based on the ideXlab platform.

  • interactive effect of brassinosteroids and cytokinins on growth chlorophyll monosaccharide and protein content in the green alga chlorella vulgaris trebouxiophyceae
    Plant Physiology and Biochemistry, 2014
    Co-Authors: Andrzej Bajguz, Alicja Piotrowskaniczyporuk
    Abstract:

    Interaction between brassinosteroids (BRs) (brassinolide, BL; 24-epibrassinolide, 24-epiBL; 28-homobrassinolide, 28-homoBL; Castasterone, CS; 24-epiCastasterone, 24-epiCS; 28-homoCastasterone, 28-homoCS) and adenine- (trans-zeatin, tZ; kinetin, Kin) as well as phenylurea-type (1,3-diphenylurea, DPU) cytokinins (CKs) in the regulation of cell number, phytohormone level and the content of chlorophyll, monosaccharide and protein in unicellular green alga Chlorella vulgaris (Trebouxiophyceae) were examined. Chlorella vulgaris exhibited sensitivity to CKs in the following order of their stimulating properties: 10 nM tZ > 100 nM Kin >1 μM DPU. Exogenously applied BRs possessed the highest biological activity in algal cells at concentration of 10 nM. Among the BRs, BL was characterized by the highest activity, while 28-homoCS - by the lowest. The considerable increase in the level of all endogenous BRs by 27–46% was observed in C. vulgaris culture treated with exogenous 10 nM tZ. It can be speculated that CKs may stimulate BR activity in C. vulgaris by inducing the accumulation of endogenous BRs. CKs interacted synergistically with BRs increasing the number of cells and endogenous accumulation of proteins, chlorophylls and monosaccharides in C. vulgaris. The highest stimulation of algal growth and the contents of analyzed biochemical parameters were observed for BL applied in combination with tZ, whereas the lowest in the culture treated with both 28-homoCS and DPU. However, regardless of the applied mixture of BRs with CKs, the considerable increase in cell number and the metabolite accumulation was found above the level obtained in cultures treated with any single phytohormone in unicellular green alga C. vulgaris.

  • synergistic effect of auxins and brassinosteroids on the growth and regulation of metabolite content in the green alga chlorella vulgaris trebouxiophyceae
    Plant Physiology and Biochemistry, 2013
    Co-Authors: Andrzej Bajguz, Alicja Piotrowskaniczyporuk
    Abstract:

    The relationships between brassinosteroids (BRs) (brassinolide, BL; 24-epiBL; 28-homoBL; Castasterone, CS; 24-epiCS; 28-homoCS) and auxins (indole-3-acetic acid, IAA; indole-3-butyric acid, IBA; indole-3-propionic acid, IPA) in the regulation of cell number, phytohormone level and metabolism in green alga Chlorella vulgaris were investigated. Exogenously applied auxins had the highest biological activity in algal cells at 50 μM. Among the auxins, IAA was characterized by the highest activity, while IBA - by the lowest. BRs at 0.01 μM were characterized by the highest biological activity in relation to auxin-treated and untreated cultures of C. vulgaris. The application of 50 μM IAA stimulated the level of all detected endogenous BRs in C. vulgaris cells. The stimulatory effect of BRs in green algae was arranged in the following order: BL > 24-epiBL > 28-homoBL > CS > 24-epiCS > 28-homoCS. Auxins cooperated synergistically with BRs stimulating algal cell proliferation and endogenous accumulation of proteins, chlorophylls and monosaccharides in C. vulgaris. The highest stimulation of algal growth and the contents of analyzed biochemical parameters were observed for the mixture of BL with IAA, whereas the lowest in the culture treated with both 28-homoCS and IBA. However, regardless of the applied mixture of BRs with auxins, the considerable increase in cell number and the metabolite accumulation was found above the level obtained in cultures treated with any single phytohormone. Obtained results confirm that both groups of plant hormones cooperate synergistically in the control of growth and metabolism of unicellular green alga C. vulgaris.

Takao Yokota - One of the best experts on this subject based on the ideXlab platform.

  • Occurrence of brassinosteroids in non-flowering land plants, liverwort, moss, lycophyte and fern
    Phytochemistry, 2017
    Co-Authors: Takao Yokota, Toshiyuki Ohnishi, Kyomi Shibata, Masashi Asahina, Takahito Nomura, Tomomichi Fujita, Kimitsune Ishizaki, Takayuki Kohchi
    Abstract:

    Endogenous brassinosteroids (BRs) in non-flowering land plants were analyzed. BRs were found in a liverwort (Marchantia polymorpha), a moss (Physcomitrella patens), lycophytes (Selaginella moellendorffii and S. uncinata) and 13 fern species. A biologically active BR, Castasterone (CS), was identified in most of these non-flowering plants but another biologically active BR, brassinolide, was not. It may be distinctive that levels of CS in non-flowering plants were orders of magnitude lower than those in flowering plants. 22-Hydroxycampesterol and its metabolites were identified in most of the non-flowering plants suggesting that the biosynthesis of BRs via 22-hydroxylation of campesterol occurs as in flowering plants. Phylogenetic analyses indicated that M. polymorpha, P. patens and S. moellendorffii have cytochrome P450s in the CYP85 clans which harbors BR biosynthesis enzymes, although the P450 profiles are simpler as compared with Arabidopsis and rice. Furthermore, these basal land plants were found to have multiple P450s in the CYP72 clan which harbors enzymes to catabolize BRs. These findings indicate that green plants were able to synthesize and inactivate BRs from the land-transition stage.

  • Rapid Report Identification of Castasterone, 6-DeoxoCastasterone, Typhasterol and 6-DeoxotyphasteroI from the Shoots of Arabidopsis thaliana
    2016
    Co-Authors: Yong-hwa Choi, Suguru Takatsuto, Takao Yokota, Joanne Chory, Akira Sakurai
    Abstract:

    Endogenous brassinosteroids in the shoots of Arabi-dopsis thaliana were investigated. Castasterone, 6-deoxo-Castasterone, typhasterol and 6-deoxotyphasterol were identified by GC-MS. The co-occurrence of 6-deoxo-bras-sinosteroids and 6-oxo-brassinosteroids suggests that there are both early and late C6-oxidation pathways of brassino-steroids in A. thaliana. Key words: Arabidopsis thaliana — Early C6-oxidation pathway — Endogenous brassinosteroids — Late C6-oxida-tion pathway — Shoot. We have studied biosynthesis of brassinosteroids, steroidal plant hormones, using cultured cells of Catharan-thus roseus, and the biosynthetic pathway from plant sterols to brassinolide has been elucidated (Yokota et al. 1990, Suzuki et al. 1993, 1994a, b, 1995a, Fujioka et al

  • blue light promoted rice leaf bending and unrolling are due to up regulated brassinosteroid biosynthesis genes accompanied by accumulation of Castasterone
    Phytochemistry, 2014
    Co-Authors: Masashi Asahina, Kyomi Shibata, Takahito Nomura, Yuji Tamaki, Tomoaki Sakamoto, Takao Yokota
    Abstract:

    In this study the relationship between blue light- and brassinosteroid-enhanced leaf lamina bending and unrolling in rice was investigated. Twenty-four hours (h) irradiation with white or blue light increased endogenous brassinosteroid levels, especially those of typhasterol and Castasterone, in aerial tissues of rice seedlings. There was an accompanying up-regulation of transcript levels of CYP85A1/OsDWARF, encoding an enzyme catalyzing C-6 oxidation, after 6h under either white or blue light. These effects were not observed in seedlings placed under far-red or red light regimes. It was concluded that blue light up-regulates the levels of several cytochrome P450 enzymes including CYP85A1, thereby promoting the synthesis of Castasterone, a biologically active brassinosteroid in rice. Based on these findings, it is considered that blue light-mediated rice leaf bending and unrolling are consequences of the enhanced biosynthesis of endogenous Castasterone. In contrast to aerial tissues, brassinosteroid synthesis in roots appeared to be negatively regulated by white, blue and red light but positively controlled by far-red light.

  • accumulation of 6 deoxocathasterone and 6 deoxoCastasterone in arabidopsis pea and tomato is suggestive of common rate limiting steps in brassinosteroid biosynthesis
    Phytochemistry, 2001
    Co-Authors: Takahito Nomura, Gerard J Bishop, Suguru Takatsuto, Tatsuro Sato, Yuji Kamiya, Takao Yokota
    Abstract:

    To gain a better understanding of brassinosteroid biosynthesis, the levels of brassinosteroids and sterols related to brassinolide biosynthesis in Arabidopsis, pea, and tomato plants were quantified by gas chromatography-selected ion monitoring. In these plants, the late C-6 oxidation pathway was found to be the predominant pathway in the synthesis of Castasterone. Furthermore, all these plant species had similar BR profiles, suggesting the presence of common biosynthetic control mechanisms. The especially high levels of 6-deoxocathasterone and 6-deoxoCastasterone may indicate that their respective conversions to 6-deoxoteasterone and Castasterone are regulated in planta and hence are important rate-limiting steps in brassinosteroid biosynthesis. Other possible rate-limiting reactions, including the conversion of campestanol to 6-deoxocathasteonre, are also discussed. Tomato differs from Arabidopsis and pea in that tomato contains 28-norCastasterone as a biologically active brassinosteroid, and that its putative precursors, cholesterol and its relatives are the major sterols.

  • brassinosteroid sterol synthesis and plant growth as affected by lka and lkb mutations of pea
    Plant Physiology, 1999
    Co-Authors: Takahito Nomura, Suguru Takatsuto, James B. Reid, Yukiko Kitasaka, Motohiro Fukami, Takao Yokota
    Abstract:

    The dwarf pea ( Pisum sativum ) mutants lka and lkb are brassinosteroid (BR) insensitive and deficient, respectively. The dwarf phenotype of the lkb mutant was rescued to wild type by exogenous application of brassinolide and its biosynthetic precursors. Gas chromatography-mass spectrometry analysis of the endogenous sterols in this mutant revealed that it accumulates 24-methylenecholesterol and isofucosterol but is deficient in their hydrogenated products, campesterol and sitosterol. Feeding experiments using 2 H-labeled 24-methylenecholesterol indicated that the lkb mutant is unable to isomerize and/or reduce the Δ 24(28) double bond. Dwarfism of the lkb mutant is, therefore, due to BR deficiency caused by blocked synthesis of campesterol from 24-methylenecholesterol. The lkb mutation also disrupted sterol composition of the membranes, which, in contrast to those of the wild type, contained isofucosterol as the major sterol and lacked stigmasterol. The lka mutant was not BR deficient, because it accumulated Castasterone. Like some gibberellin-insensitive dwarf mutants, overproduction of Castasterone in the lka mutant may be ascribed to the lack of a feedback control mechanism due to impaired perception/signal transduction of BRs. The possibility that Castasterone is a biologically active BR is discussed.