Search

Your search keyword '"Jakobsen Iver"' showing total 528 results
Start Over Author "Jakobsen Iver"
528 results on '"Jakobsen Iver"'

1. Protocol: using virus-induced gene silencing to study the arbuscular mycorrhizal symbiosis in Pisum sativum

Author

Johansen Elisabeth I, Olsen Anne, Grønlund Mette, and Jakobsen Iver

Subjects
Plant culture, SB1-1110, Biology (General), QH301-705.5
Abstract

Abstract Virus-induced gene silencing (VIGS) is an alternative reverse genetics tool for silencing of genes in some plants, which are difficult to transform. The pea early-browning virus (PEBV) has been developed as a VIGS vector and used in pea for functional analysis of several genes. However, the available PEBV-VIGS protocols are inadequate for studying genes involved in the symbiosis with arbuscular mycorrhizal fungi (AMF). Here we describe a PEBV-VIGS protocol suitable for reverse genetics studies in pea of genes involved in the symbiosis with AMF and show its effectiveness in silencing genes involved in the early and late stages of AMF symbiosis.

Published
2010
Full Text
View/download PDF

2. Investigations of barley stripe mosaic virus as a gene silencing vector in barley roots and in Brachypodium distachyon and oat

Author

Nilsson Lena, Barciszewska-Pacak Maria, Jørgensen Bodil, Geisler Katrin, Pacak Andrzej, Nielsen Tom, Johansen Elisabeth, Grønlund Mette, Jakobsen Iver, and Albrechtsen Merete

Subjects
Plant culture, SB1-1110, Biology (General), QH301-705.5
Abstract

Abstract Background Gene silencing vectors based on Barley stripe mosaic virus (BSMV) are used extensively in cereals to study gene function, but nearly all studies have been limited to genes expressed in leaves of barley and wheat. However since many important aspects of plant biology are based on root-expressed genes we wanted to explore the potential of BSMV for silencing genes in root tissues. Furthermore, the newly completed genome sequence of the emerging cereal model species Brachypodium distachyon as well as the increasing amount of EST sequence information available for oat (Avena species) have created a need for tools to study gene function in these species. Results Here we demonstrate the successful BSMV-mediated virus induced gene silencing (VIGS) of three different genes in barley roots, i.e. the barley homologues of the IPS1, PHR1, and PHO2 genes known to participate in Pi uptake and reallocation in Arabidopsis. Attempts to silence two other genes, the Pi transporter gene HvPht1;1 and the endo-β-1,4-glucanase gene HvCel1, in barley roots were unsuccessful, probably due to instability of the plant gene inserts in the viral vector. In B. distachyon leaves, significant silencing of the PHYTOENE DESATURASE (BdPDS) gene was obtained as shown by photobleaching as well as quantitative RT-PCR analysis. On the other hand, only very limited silencing of the oat AsPDS gene was observed in both hexaploid (A. sativa) and diploid (A. strigosa) oat. Finally, two modifications of the BSMV vector are presented, allowing ligation-free cloning of DNA fragments into the BSMV-γ component. Conclusions Our results show that BSMV can be used as a vector for gene silencing in barley roots and in B. distachyon leaves and possibly roots, opening up possibilities for using VIGS to study cereal root biology and to exploit the wealth of genome information in the new cereal model plant B. distachyon. On the other hand, the silencing induced by BSMV in oat seemed too weak to be of practical use. The new BSMV vectors modified for ligation-free cloning will allow rapid insertion of plant gene fragments for future experiments.

Published
2010
Full Text
View/download PDF

4. A tribute to Sally E. Smith

Author

Martin, Francis M., Dickie, Ian, Lindahl, Björn D., Lennon, Sarah, Öpik, Maarja, Polle, Andrea, Requena, Natalia, Selosse, Marc-André, Koide, Roger T., Jakobsen, Iver, Watts-Williams, Stephanie J., and Cavagnaro, Timothy R.

Published
2020

29. Nutrient Dynamics in Arbuscular Mycorrhizal Networks

Author

Jakobsen, Iver, Hammer, Edith C., Caldwell, Martyn M., Series editor, Díaz, Sandra, Series editor, Heldmaier, Gerhard, Series editor, Jackson, Robert B., Series editor, Lange, Otto L., Series editor, Levia, Delphis F., Series editor, Mooney, Harold A., Series editor, Schulze, Ernst-Detlef, Series editor, Sommer, Ulrich, Series editor, and Horton, Thomas R., editor

Published
2015
Full Text
View/download PDF

36. Co-ordinated Changes in the Accumulation of Metal Ions in Maize (Zea mays ssp. mays L.) in Response to Inoculation with the Arbuscular Mycorrhizal Fungus Funneliformis mosseae

Author

Ram[REPLACEMENT CHARACTER]rez-Flores, M Rosario, Rell[REPLACEMENT CHARACTER]n-[REPLACEMENT CHARACTER]lvarez, Rub[REPLACEMENT CHARACTER]n, Wozniak, Barbara, Gebreselassie, Mesfin-Nigussie, Jakobsen, Iver, Olalde-Portugal, V[REPLACEMENT CHARACTER]ctor, Baxter, Ivan, Paszkowski, Uta, and Sawers, Ruairidh J H

Published
2017
Full Text
View/download PDF

39. Multimodal correlative imaging 1 and modelling of phosphorus 2 uptake from soil by hyphae of mycorrhizal fungi

Author

Keyes, Samuel D, Van Veelen, Arjen, Mckay Fletcher, Daniel, Scotson, Callum, Koebernick, Nicolai, Petroselli, Chiara, Williams, Katherine, Ruiz, Siul Aljadi, Cooper, Laura, Mayon, Robert B, Duncan, Simon, Dumont, Marc, Jakobsen, Iver, Oldroyd, Giles, Tkacz, Andrzej, Poole, Philip, Mosselmans, Fred, Borca, Camelia, Huthwelker, Thomas, Jones, David L., and Roose, Tiina

Abstract

• Phosphorus (P) is essential for plant growth. Arbuscular mycorrhizal fungi (AMF) aid its uptake by acquiring sources distant from roots in return for carbon. Little is known about how AMF colonise soil pore-space, and models of AMF-enhanced P-uptake are poorly validated.• We used synchrotron X-ray computed tomography (SXRCT) to visualize mycorrhizae in soil, and synchrotron X-ray fluorescence (XRF/XANES) elemental mapping for phosphorus (P), sulphur (S) and aluminium (Al), in combination with modelling.• We found that AMF inoculation had a suppressive effect on colonisation by other soil fungi and identified differences in structure and growth rate between hyphae of AMF and nonmycorrhizal fungi. Results showed that AMF co-locate with areasof high P and low Al, andpreferentially associate with organic-type P species in preference to Al-rich inorganic P.• We discovered that AMF avoid Al-rich areas as a source of P. S-rich regions correlated with higher hyphal density and an increased organic-associated P-pool, whilst oxidized S-species were found close to AMF hyphae. Increased S oxidation close to AMF suggested the observed changes were microbiome-related. Our experimentally-validated model led to an estimate of P-uptake by AMF hyphae that is an order of magnitude lower than rates previously estimated; a result with significant implications for modelling of plant-soil-AMF interactions.

Published
2022

41. Multimodal correlative imaging and modelling of phosphorus uptake from soil by hyphae of mycorrhizal fungi

Author

Keyes, Sam, van Veelen, Arjen, McKay Fletcher, Dan, Scotson, Callum, Koebernick, Nico, Petroselli, Chiara, Williams, Katherine, Ruiz, Siul, Cooper, Laura, Mayon, Robbie, Duncan, Simon, Dumont, Marc, Jakobsen, Iver, Oldroyd, Giles, Tkacz, Andrzej, Poole, Philip, Mosselmans, Fred, Borca, Camelia, Huthwelker, Thomas, Jones, David L., Roose, Tiina, Keyes, Sam, van Veelen, Arjen, McKay Fletcher, Dan, Scotson, Callum, Koebernick, Nico, Petroselli, Chiara, Williams, Katherine, Ruiz, Siul, Cooper, Laura, Mayon, Robbie, Duncan, Simon, Dumont, Marc, Jakobsen, Iver, Oldroyd, Giles, Tkacz, Andrzej, Poole, Philip, Mosselmans, Fred, Borca, Camelia, Huthwelker, Thomas, Jones, David L., and Roose, Tiina

Abstract

Phosphorus (P) is essential for plant growth. Arbuscular mycorrhizal fungi (AMF) aid its uptake by acquiring P from sources distant from roots in return for carbon. Little is known about how AMF colonise soil pore-space, and models of AMF-enhanced P-uptake are poorly validated. We used synchrotron X-ray computed tomography to visualize mycorrhizas in soil and synchrotron X-ray fluorescence/X-ray absorption near edge structure (XRF/XANES) elemental mapping for P, sulphur (S) and aluminium (Al) in combination with modelling. We found that AMF inoculation had a suppressive effect on colonisation by other soil fungi and identified differences in structure and growth rate between hyphae of AMF and nonmycorrhizal fungi. Our results showed that AMF co-locate with areas of high P and low Al, and preferentially associate with organic-type P species over Al-rich inorganic P. We discovered that AMF avoid Al-rich areas as a source of P. Sulphur-rich regions were found to be correlated with higher hyphal density and an increased organic-associated P-pool, whilst oxidized S-species were found close to AMF hyphae. Increased S oxidation close to AMF suggested the observed changes were microbiome-related. Our experimentally-validated model led to an estimate of P-uptake by AMF hyphae that is an order of magnitude lower than rates previously estimated – a result with significant implications for the modelling of plant–soil–AMF interactions.

Published
2022

49. Multimodal correlative imaging and modelling of phosphorus uptake from soil by hyphae of mycorrhizal fungi

Author

Keyes, Sam, primary, van Veelen, Arjen, additional, McKay Fletcher, Dan, additional, Scotson, Callum, additional, Koebernick, Nico, additional, Petroselli, Chiara, additional, Williams, Katherine, additional, Ruiz, Siul, additional, Cooper, Laura, additional, Mayon, Robbie, additional, Duncan, Simon, additional, Dumont, Marc, additional, Jakobsen, Iver, additional, Oldroyd, Giles, additional, Tkacz, Andrzej, additional, Poole, Philip, additional, Mosselmans, Fred, additional, Borca, Camelia, additional, Huthwelker, Thomas, additional, Jones, David L., additional, and Roose, Tiina, additional

Published
2022
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results