Change search
ReferencesLink to record
Permanent link

Direct link
Infection thread growth mechanism is conserved between legumes and actinorhizal Casuarina glauca, but seems different in actinorhizal Datisca glomerata
Stockholm University, Faculty of Science, Department of Botany. (Katharina Pawlowski)
(English)Manuscript (preprint) (Other academic)
Abstract [en]

In this study, two previously analysed infection-related promoters were examined for their expression pattern in nodules formed on transgenic hairy roots of the actinorhizal species Datisca glomerata. The infected cell-specific expression pattern of a leghemoglobin promoter from the indeterminate nodule-forming legume Vicia faba was conserved in the determinate nodule-forming legume Lotus japonicus, the actinorhizal species Casuarina glauca (Fagales) and also in D. glomerata (Cucurbitales). Hence, the conservation of the infected cell-specific transcription factors responsible for the activation of leghemoglobin genes in legumes, and the symbiotic haemoglobin gene in C. glauca, extends to actinorhizal Cucurbitales. However, the infection thread containing cell-specific expression pattern of the C. glauca Cg12 promoter which had been found to be conserved in legumes (Svistoonoff et al. 2004), was not conserved in D. glomerata. In order to find out whether this result, in combination with the long-known fact that infection thread growth in D. glomerata does not involve the formation of pre-infection thread structures like in legumes and actinorhizal Fagales, points at an alternative infection thread growth mechanism in actinorhizal Cucurbitales, a cytological analysis of infection thread growth in D. glomerata vs. Alnus rubra (Fagales) was performed. In D. glomerata, infection threads crossed the cell wall through the center of pit fields, while in A. rubra no correlation between infection thread crossing points and thin cell wall regions could be found.  Moreover, extensive ramification of infection threads in the cell periphery of D. glomerata infected cells leads to multiple pit field penetrations in a given host cell and a large degree of inter-host cell communication by the microsymbiont, in contrast to only a few wall penetration sites, aligned axially, in A. rubra

URN: urn:nbn:se:su:diva-42403OAI: diva2:346010
Available from: 2010-08-30 Created: 2010-08-30 Last updated: 2010-08-30Bibliographically approved
In thesis
1. Conservation of transcription factors in infected cells of nitrogen-fixing root nodules
Open this publication in new window or tab >>Conservation of transcription factors in infected cells of nitrogen-fixing root nodules
2010 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Infected cells of nitrogen-fixing root nodules are the only plant cells that can stably internally accommodate a eubacterial symbiont. In the context of studying the differentiation of infected cells, we set about to analyse the conservation of infected cell-specific transcription factors using altogether four different promoters from genes showing infected cell-specific expression, or nodule-specific expression. The activity of promoter-reporter gene constructs was compared in transgenic hairy root systems of three different root nodule-forming plant species. The model species were two actinorhizal plants; the tree Casuarina glauca and the riparian weed Datisca glomerata, and the model legume Lotus japonicus. C. glauca and D. glomerata belong to different phylogenetic subgroups (Fagales vs. Cucurbitales) of actinorhizal plants showing strong differences with regard to nodule morphology, -metabolism and infection mechanism.

The results indicate one type of infected cell-specific transcription factors previously shown to be conserved between legumes and C. glauca is also conserved in D. glomerata. However, another type of transcription factor specific to infection thread-containing cells of C. glauca and the model legume Medicago truncatula is not conserved in D. glomerata. These results indicate that in this group of actinorhizal plants, infection thread growth occurs via a different mechanism, a conclusion supported by cytological analysis.

Furthermore, the results indicate that gene expression in infected cells of root nodules can be achieved by control mechanisms other than cell type-specific transcription factors, and that in this context, phytohormone regulation deserves further study.

Place, publisher, year, edition, pages
Stockholm: Department of Botany, Stockholm University, 2010. 69 p.
root nodules, actinorhiza, legumes, infection thread, Frankia, subtilase, leghemoglobin, chitinase
National Category
Research subject
Plant Physiology
urn:nbn:se:su:diva-42389 (URN)978-91-7447-140-3 (ISBN)
Public defence
2010-10-08, Föresläsningssalen Botanicum, Lilla Frescativägen 5, Stockholm, 10:00 (English)
At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 1: Manuscript. Paper 2: Manuscript. Paper 3: Manuscript. Paper 4: Manuscript.Available from: 2010-09-16 Created: 2010-08-27 Last updated: 2010-08-30Bibliographically approved

Open Access in DiVA

No full text

Search in DiVA

By author/editor
Rashidi, Behnoosh
By organisation
Department of Botany

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 79 hits
ReferencesLink to record
Permanent link

Direct link