The Experts below are selected from a list of 417 Experts worldwide ranked by ideXlab platform
Adriano Sofo - One of the best experts on this subject based on the ideXlab platform.
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Hormonal response and root architecture in Arabidopsis thaliana subjected to heavy metals
PAGEPress Publications, 2014Co-Authors: Antonella Vitti, Antonio Scopa, Maria Nuzzaci, Giuseppe Tataranni, Imma Tamburrino, Adriano SofoAbstract:In this work, specific concentrations of cadmium, copper and zinc in double combination, were supplied for 12 days to growing seedlings of the model species Arabidopsis thaliana. Metal accumulation was measured in roots and shoots. Microscopic analyses revealed that root morphology was affected by metals, and that the root and shoot levels of indole-3-acetic acid, trans-zeatin riboside and Dihydrozeatin riboside varied accordingly. Minor modifications in gibberellic acid levels occurred in the Zinc treatments, whereas abscisic acid level did not change after the exposition to metals. Reverse transcription polymerase chain reaction analysis of some genes involved in auxin and cytokinin synthesis (AtAAO, AtNIT and AtIPT) revealed that their expression were not affected by metal treatments. The root morphological alterations that resulted in an increased surface area, due to the formation of root hairs and lateral roots, could be signs of the response to metal stress in terms of a functionally-addressed reorientation of root growth. The root system plasticity observed could be important for better understanding the manner in which the root architecture is shaped by environmental and hormonal stimuli
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auxin and cytokinin metabolism and root morphological modifications in arabidopsis thaliana seedlings infected with cucumber mosaic virus cmv or exposed to cadmium
International Journal of Molecular Sciences, 2013Co-Authors: Antonella Vitti, Antonio Scopa, Maria Nuzzaci, Giuseppe Tataranni, Tony Remans, Jaco Vangronsveld, Adriano SofoAbstract:Arabidopsis thaliana L. is a model plant but little information is available about morphological root changes as part of a phytohormonal common response against both biotic and abiotic stressors. For this purpose, two-week-old Arabidopsis seedlings were treated with 10 µM CdSO4 or infected with CMV. After 12 days the entire aerial parts and the root system were analyzed, and the presence of CMV or the accumulation of Cd were detected. Microscopic analysis revealed that both CMV and Cd influenced root morphology by a marked development in the length of root hairs and an intense root branching if compared to controls. Among the three treatments, Cd-treated seedlings showed a shorter root axis length and doubled their lateral root diameter, while the lateral roots of CMV-infected seedlings were the longest. The root growth patterns were accompanied by significant changes in the levels of indole-3-acetic acid, trans-zeatin riboside, Dihydrozeatin riboside, as a probable consequence of the regulation of some genes involved in their biosynthesis/degradation. The opposite role on root development played by the phythormones studied is discussed in detail. The results obtained could provide insights into novel strategies for plant defense against pathogens and plant protection against pollutants.
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Auxin and Cytokinin Metabolism and Root Morphological Modifications in Arabidopsis thaliana Seedlings Infected with Cucumber mosaic virus (CMV) or Exposed to Cadmium
2013Co-Authors: Antonella Vitti, Antonio Scopa, Maria Nuzzaci, Tony Remans, Jaco Vangronsveld, Adriano SofoAbstract:Abstract: Arabidopsis thaliana L. is a model plant but little information is available about morphological root changes as part of a phytohormonal common response against both biotic and abiotic stressors. For this purpose, two-week-old Arabidopsis seedlings were treated with 10 µM CdSO4 or infected with CMV. After 12 days the entire aerial parts and the root system were analyzed, and the presence of CMV or the accumulation of Cd were detected. Microscopic analysis revealed that both CMV and Cd influenced root morphology by a marked development in the length of root hairs and an intense root branching if compared to controls. Among the three treatments, Cd-treated seedlings showed a shorter root axis length and doubled their lateral root diameter, while the lateral roots of CMV-infected seedlings were the longest. The root growth patterns were accompanied by significant changes in the levels of indole-3-acetic acid, trans-zeatin riboside, Dihydrozeatin riboside, as a probable consequence of the regulation of some genes involved in their biosynthesis/degradation. The opposite role on root development played by the phythormones studied is discussed in detail. The results obtained could provideInt. J. Mol. Sci. 2013, 14 689
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trichoderma harzianum strain t 22 induces changes in phytohormone levels in cherry rootstocks prunus cerasus p canescens
Plant Growth Regulation, 2011Co-Authors: Adriano Sofo, Antonio Scopa, Michele Manfra, Mauro De Nisco, Gian Carlo Tenore, Jacopo Troisi, Raffaele Di Fiori, Ettore NovellinoAbstract:The aim of this research was to explain the direct plant growth-promoting activity of Trichoderma harzianum strain T-22 (T22), hypothesizing the involvement of different classes of plant growth regulators. Seven days after the transfer to root-inducing medium, in vitro-cultured shoots of GiSeLa6® (Prunus cerasus × P. canescens) were inoculated with T22. Root and shoot growth were significantly affected by T22 (+76 and +61%, respectively). Ten days after inoculation, the levels of indole-3-acetic acid (IAA), trans-zeatin riboside (t-ZR), Dihydrozeatin riboside (DHZR), gibberellic acid (GA3) and abscisic acid (ABA) were analyzed by high performance liquid chromatography coupled with mass spectrometry. The results showed that after T22-inoculation, IAA and GA3 significantly increased in both leaves (+49 and +71%, respectively) and roots (+40 and +143%, respectively) whereas t-ZR decreased (−51% in leaves and −37% in roots). Changes in DHZR were observed in T22-inoculated roots (−32%) but not in leaves, whereas the levels of ABA did not differ between the two treatments. The extraction method allowed the simultaneous extraction of phytohormones. There is evidence that the change in phytohormone levels is one of the direct mechanism by which T22 promotes rooting and shoot growth, with notable advantages for rootstock production during nursery processes.
Antonio Scopa - One of the best experts on this subject based on the ideXlab platform.
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Hormonal response and root architecture in Arabidopsis thaliana subjected to heavy metals
PAGEPress Publications, 2014Co-Authors: Antonella Vitti, Antonio Scopa, Maria Nuzzaci, Giuseppe Tataranni, Imma Tamburrino, Adriano SofoAbstract:In this work, specific concentrations of cadmium, copper and zinc in double combination, were supplied for 12 days to growing seedlings of the model species Arabidopsis thaliana. Metal accumulation was measured in roots and shoots. Microscopic analyses revealed that root morphology was affected by metals, and that the root and shoot levels of indole-3-acetic acid, trans-zeatin riboside and Dihydrozeatin riboside varied accordingly. Minor modifications in gibberellic acid levels occurred in the Zinc treatments, whereas abscisic acid level did not change after the exposition to metals. Reverse transcription polymerase chain reaction analysis of some genes involved in auxin and cytokinin synthesis (AtAAO, AtNIT and AtIPT) revealed that their expression were not affected by metal treatments. The root morphological alterations that resulted in an increased surface area, due to the formation of root hairs and lateral roots, could be signs of the response to metal stress in terms of a functionally-addressed reorientation of root growth. The root system plasticity observed could be important for better understanding the manner in which the root architecture is shaped by environmental and hormonal stimuli
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auxin and cytokinin metabolism and root morphological modifications in arabidopsis thaliana seedlings infected with cucumber mosaic virus cmv or exposed to cadmium
International Journal of Molecular Sciences, 2013Co-Authors: Antonella Vitti, Antonio Scopa, Maria Nuzzaci, Giuseppe Tataranni, Tony Remans, Jaco Vangronsveld, Adriano SofoAbstract:Arabidopsis thaliana L. is a model plant but little information is available about morphological root changes as part of a phytohormonal common response against both biotic and abiotic stressors. For this purpose, two-week-old Arabidopsis seedlings were treated with 10 µM CdSO4 or infected with CMV. After 12 days the entire aerial parts and the root system were analyzed, and the presence of CMV or the accumulation of Cd were detected. Microscopic analysis revealed that both CMV and Cd influenced root morphology by a marked development in the length of root hairs and an intense root branching if compared to controls. Among the three treatments, Cd-treated seedlings showed a shorter root axis length and doubled their lateral root diameter, while the lateral roots of CMV-infected seedlings were the longest. The root growth patterns were accompanied by significant changes in the levels of indole-3-acetic acid, trans-zeatin riboside, Dihydrozeatin riboside, as a probable consequence of the regulation of some genes involved in their biosynthesis/degradation. The opposite role on root development played by the phythormones studied is discussed in detail. The results obtained could provide insights into novel strategies for plant defense against pathogens and plant protection against pollutants.
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Auxin and Cytokinin Metabolism and Root Morphological Modifications in Arabidopsis thaliana Seedlings Infected with Cucumber mosaic virus (CMV) or Exposed to Cadmium
2013Co-Authors: Antonella Vitti, Antonio Scopa, Maria Nuzzaci, Tony Remans, Jaco Vangronsveld, Adriano SofoAbstract:Abstract: Arabidopsis thaliana L. is a model plant but little information is available about morphological root changes as part of a phytohormonal common response against both biotic and abiotic stressors. For this purpose, two-week-old Arabidopsis seedlings were treated with 10 µM CdSO4 or infected with CMV. After 12 days the entire aerial parts and the root system were analyzed, and the presence of CMV or the accumulation of Cd were detected. Microscopic analysis revealed that both CMV and Cd influenced root morphology by a marked development in the length of root hairs and an intense root branching if compared to controls. Among the three treatments, Cd-treated seedlings showed a shorter root axis length and doubled their lateral root diameter, while the lateral roots of CMV-infected seedlings were the longest. The root growth patterns were accompanied by significant changes in the levels of indole-3-acetic acid, trans-zeatin riboside, Dihydrozeatin riboside, as a probable consequence of the regulation of some genes involved in their biosynthesis/degradation. The opposite role on root development played by the phythormones studied is discussed in detail. The results obtained could provideInt. J. Mol. Sci. 2013, 14 689
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trichoderma harzianum strain t 22 induces changes in phytohormone levels in cherry rootstocks prunus cerasus p canescens
Plant Growth Regulation, 2011Co-Authors: Adriano Sofo, Antonio Scopa, Michele Manfra, Mauro De Nisco, Gian Carlo Tenore, Jacopo Troisi, Raffaele Di Fiori, Ettore NovellinoAbstract:The aim of this research was to explain the direct plant growth-promoting activity of Trichoderma harzianum strain T-22 (T22), hypothesizing the involvement of different classes of plant growth regulators. Seven days after the transfer to root-inducing medium, in vitro-cultured shoots of GiSeLa6® (Prunus cerasus × P. canescens) were inoculated with T22. Root and shoot growth were significantly affected by T22 (+76 and +61%, respectively). Ten days after inoculation, the levels of indole-3-acetic acid (IAA), trans-zeatin riboside (t-ZR), Dihydrozeatin riboside (DHZR), gibberellic acid (GA3) and abscisic acid (ABA) were analyzed by high performance liquid chromatography coupled with mass spectrometry. The results showed that after T22-inoculation, IAA and GA3 significantly increased in both leaves (+49 and +71%, respectively) and roots (+40 and +143%, respectively) whereas t-ZR decreased (−51% in leaves and −37% in roots). Changes in DHZR were observed in T22-inoculated roots (−32%) but not in leaves, whereas the levels of ABA did not differ between the two treatments. The extraction method allowed the simultaneous extraction of phytohormones. There is evidence that the change in phytohormone levels is one of the direct mechanism by which T22 promotes rooting and shoot growth, with notable advantages for rootstock production during nursery processes.
Harry Van Onckelen - One of the best experts on this subject based on the ideXlab platform.
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Cytokinins in Tobacco and Wheat Chloroplasts. Occurrence and Changes Due to Light/Dark Treatment
Plant physiology, 1999Co-Authors: Eva Benková, Václav Motyka, Erwin Witters, Walter Van Dongen, Jan Kolar, Bretislav Brzobohatý, Harry Van Onckelen, Ivana MacháčkováAbstract:Although cytokinins (CKs) affect a number of processes connected with chloroplasts, it has never been rigorously proven that chloroplasts contain CKs. We isolated intact chloroplasts from tobacco ( Nicotiana tabacum L. cv SR1) and wheat ( Triticum aestivum L. cv Ritmo) leaves and determined their CKs by liquid chromatography/tandem mass spectroscopy. Chloroplasts from both species contained a whole spectrum of CKs, including free bases (zeatin and isopentenyladenine), ribosides (zeatin riboside, and isopentenyladenosine), ribotides (isopentenyladenosine-5′-monophosphate, zeatin riboside-5′-monophosphate, and Dihydrozeatin riboside-5′-monophosphate), and N -glucosides (zeatin- N 9 -glucoside, Dihydrozeatin- N 9 -glucoside, zeatin- N 7 -glucoside, and isopentenyladenine- N -glucosides). In chloroplasts there was a moderately higher relative amount of bases, ribosides, and ribotides than in leaves, and a significantly increased level of N 9 -glucosides of zeatin and Dihydrozeatin. Tobacco and wheat chloroplasts were prepared from leaves at the end of either a dark or light period. After a dark period, chloroplasts accumulated more CKs than after a light period. The differences were moderate for free bases and ribosides, but highly significant for glucosides. Tobacco chloroplasts from dark-treated leaves contained zeatin riboside- O -glucoside and Dihydrozeatin riboside- O -glucoside, as well as a relatively high CK oxidase activity. These data show that chloroplasts contain a whole spectrum of CKs and the enzymatic activity necessary for their metabolism.
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Dynamics of Cytokinins in Apical Shoot Meristems of a Day-Neutral Tobacco during Floral Transition and Flower Formation
Plant physiology, 1999Co-Authors: W. Dewitte, Miroslav Strnad, Erwin Witters, Adriana Chiappetta, Abdelkrim Azmi, Jacques Rembur, Michelle Noin, Dominique Chriqui, Harry Van OnckelenAbstract:This study considered cytokinin distribution in tobacco (Nicotiana tabacum L.) shoot apices in distinct phases of development using immunocytochemistry and quantitative tandem mass spectrometry. In contrast to vegetative apices and flower buds, we detected no free cytokinin bases (zeatin, Dihydrozeatin, or isopentenyladenine) in prefloral transition apices. We also observed a 3-fold decrease in the content of cytokinin ribosides (zeatin riboside, Dihydrozeatin riboside, and isopentenyladenosine) during this transition phase. The group concluded that organ formation (e.g. leaves and flowers) is characterized by enhanced cytokinin content, in contrast to the very low endogenous cytokinin levels found in prefloral transition apices, which showed no organogenesis. The immunocytochemical analyses revealed a differing intracellular localization of the cytokinin bases. Dihydrozeatin and isopentenyladenine were mainly cytoplasmic and perinuclear, whereas zeatin showed a clear-cut nuclear labeling. To our knowledge, this is the first time that this phenomenon has been reported. Cytokinins do not seem to act as positive effectors in the prefloral transition phase in tobacco shoot apices. Furthermore, the differences in distribution at the cellular level may be indicative of a specific physiological role of zeatin in nuclear processes.
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Levels of endogenous cytokinins, indole-3-acetic acid and abscisic acid during the cell cycle of synchronized tobacco BY-2 cells
FEBS letters, 1996Co-Authors: Pascale Redig, Orit Shaul, Dirk Inzé, Marc Van Montagu, Harry Van OnckelenAbstract:Correlation between cell cycle progression and endogenous levels of plant hormones was studied in synchronized tobacco BY-2 cell suspension cultures. Sixteen different cytokinins, indole-3-acetic acid (IAA) and abscisic acid (ABA) were extracted using solid-phase anion exchange chromatography in combination with immunoaffinity purification, and quantified by mass spectrometry. No significant correlation could be identified for IAA and ABA. In contrast, there were sharp peaks in the levels of specific cytokinins (zeatin- and Dihydrozeatin-type) at the end of the S phase and during mitosis. The levels of other cytokinins analyzed, including zeatins N- and O-glucosides, remained low, suggesting that the increased amounts of their corresponding non-glucosylated from resulted from de novo synthesis. These findings suggest that zeatin- and Dihydrozeatin-type cytokinins might play a specific regulatory role in the progression of the plant cell cycle. One hypothesis to explain cytokinin action is based on a specific interaction with kinases that regulate cell cycle progression, as has been recently shown for the cytokinin analogue olomoucine.
Johannes Van Staden - One of the best experts on this subject based on the ideXlab platform.
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Bioactive molecules derived from smoke and seaweed Ecklonia maxima showing phytohormone-like activity in Spinacia oleracea L.
New biotechnology, 2018Co-Authors: Manoj G. Kulkarni, Kannan R.r. Rengasamy, S.c. Pendota, Jiří Grúz, Lenka Plačková, Ondřej Novák, Karel Doležal, Johannes Van StadenAbstract:Bioactive compounds such as karrikinolide (KAR1 from smoke) and eckol (from the seaweed Ecklonia maxima) show promising effects on several important crop plants. These plant growth-stimulating organic biomolecules, along with crude extracts (smoke-water and Kelpak® product prepared from Ecklonia maxima), were tested on spinach plants. Eckol sprayed at 10-6 M significantly increased all the growth and biochemical parameters examined compared to control spinach plants. All tested plant growth biostimulants significantly increased total chlorophyll, carotenoids and protein content of spinach leaves. The cytokinin profile of spinach plants was also determined. Cis-zeatin, Dihydrozeatin and isopentenyladenine types of cytokinins were promoted by both smoke- and seaweed-based biostimulants. In comparison to the control plants, the level of free sinapic acid was greater in all spinach plants treated with these biostimulants. The application of these biostimulants can help spinach crop by improving growth, yield and nutritional quality; moreover, they are organic and cost-effective.
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Involvement of cis -Zeatin, Dihydrozeatin, and Aromatic Cytokinins in Germination and Seedling Establishment of Maize, Oats, and Lucerne
Journal of Plant Growth Regulation, 2011Co-Authors: Wendy A. Stirk, Václav Motyka, Miroslav Strnad, Ondřej Novák, Kateřina Václavíková, Silvia Gajdošová, Ondřej Kotland, Johannes Van StadenAbstract:The aims of this study were to monitor endogenous cytokinin levels during germination and early seedling establishment in oats, maize, and lucerne to determine which cytokinin forms are involved in these processes; to quantify the transfer ribonucleic acid (tRNA)-bound cytokinins; and to measure cytokinin oxidase/dehydrogenase (CKX) activity. Cytokinins were identified using UPLC-MS/MS. The predominant free cytokinins present in the dry seeds were Dihydrozeatin-type (DHZ) in lucerne and maize and cZ-type (cis-zeatin) in oats. Upon imbibition, there was a large increase in cZ-type cytokinins in lucerne although the cZ-type cytokinins remained at high levels in oats. In maize, the high concentrations of DHZ-type cytokinins decreased prior to radicle emergence. Four tRNA-bound cytokinins [cis-zeatin riboside (cZR)>N6-(2-isopentenyl)adenosine (iPR), Dihydrozeatin riboside (DHZR), trans-zeatin riboside (tZR)] were detected in low concentrations in all three species investigated. CKX activity was measured using an in vitro radioisotope assay. The order of substrate preference was N6-(2-isopentenyl)adenine (iP)>trans-zeatin (tZ)>cZ in all three species, with activity fluctuating as germination proceeded. There was a negative correlation between CKX activity and iP concentrations and a positive correlation between CKX activity and O-glucoside levels. As O-glucosides are less resistant to CKX degradation, they may provide a readily available source of cytokinins that can be converted to physiologically active cytokinins required during germination. Aromatic cytokinins made a very small contribution to the total cytokinin pool and increased only slightly during seedling establishment, suggesting that they do not play a major role in germination.
Lok Man S. Palni - One of the best experts on this subject based on the ideXlab platform.
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cytokinin biochemistry in relation to leaf senescence v endogenous cytokinin levels and metabolism of zeatin riboside in leaf discs from green and senescent tobacco nicotiana rustica leaves
Journal of Plant Physiology, 1992Co-Authors: Santokh Singh, Lok Man S. Palni, David S. LethamAbstract:Summary The cytokinin (bases and ribosides) content of leaf discs derived from green and senescent leaves of Nicotiana rustica was analyzed by radioimmunoassay. Zeatin was identified as the major base and Dihydrozeatin riboside as the main riboside. Leaf discs from expanded green (presenescent) leaves contained three times higher zeatin levels than those from partly-senescent leaves. The uptake and metabolic fate of [3H]-zeatin riboside supplied to discs from tobacco leaves of different maturities was also investigated. The uptake of zeatin riboside declined with an increase in leaf maturity and senescence. Zeatin riboside was rapidly inactivated mainly by side-chain cleavage. Leaf discs excised from upper green leaves metabolized zeatin riboside into inactive compounds more rapidly than did the basal senescent leaves. It is suggested that higher cytokinin levels in discs from green leaves (in comparison to senescent leaves) may result from higher uptake of xylem cytokinins and/or in situ biosynthesis of cytokinins, rather than a more rapid degradation of zeatin-type cytokinins.