Université de Fribourg

Successful joint ventures of plants: arbuscular mycorrhiza and beyond

Ercolin, Flavia ; Reinhardt, Didier

In: Trends in Plant Science, 2011, p. -

Among the oldest symbiotic associations of plants are arbuscular mycorrhiza (AM) with fungi of the phylum Glomeromycota. Although many of the symbiotic signaling components have been identified on the side of the plant, AM fungi have long evaded genetic analysis owing to their strict biotrophy and their exceptional genetics. Recently, the identification of the fungal symbiosis signal (Myc factor)...

Université de Fribourg

High resolution linkage maps of the model organism Petunia reveal substantial synteny decay with the related genome of tomato

Bossolini, Eligio ; Klahre, Ulrich ; Brandenburg, Anna ; Reinhardt, Didier ; Kuhlemeier, Cris

In: Genome, 2011, vol. 54, p. 327-340

Two linkage maps were constructed for the model plant Petunia. Mapping populations were obtained by crossing the wild species Petunia axillaris subsp. axillaris with Petunia inflata, and Petunia axillaris subsp. parodii with Petunia exserta. Both maps cover the seven chromosomes of Petunia, and span 970 centimorgans (cM) and 700 cM of the genomes, respectively. In total, 207 markers were mapped....

Université de Fribourg

Phosphate systemically inhibits development of arbuscular mycorrhiza in Petunia hybrida and represses genes involved in mycorrhizal functioning

Breuillin, Florence ; Schramm, Jonathan ; Hajirezaei, Mohammad ; Ahkami, Amir ; Favre, Patrick ; Druege, Uwe ; Hause, Bettina ; Bucher, Marcel ; Kretzschmar, Tobias ; Bossolini, Eligio ; Kuhlemeier, Cris ; Martinoia, Enrico ; Franken, Philipp ; Scholz, Uwe ; Reinhardt, Didier

In: The Plant Journal, 2010, p. -

Most terrestrial plants form arbuscular mycorrhiza (AM), mutualistic associations with soil fungi of the order Glomeromycota. The obligate biotrophic fungi trade mineral nutrients, mainly phosphate (Pi), for carbohydrates from the plants. Under conditions of high exogenous phosphate supply, when the plant can meet its own P requirements without the fungus, AM are suppressed,...

Université de Fribourg

A petunia chorismate mutase specialized for the production of floral volatiles

Colquhoun, Thomas A. ; Schimmel, Bernardus C.J. ; Kim, Joo Young ; Reinhardt, Didier ; Cline, Kenneth ; Clark, David G.

In: The Plant Journal, 2010, vol. 61, no. 1, p. 145-155

In Petunia × hybrida cv. 'Mitchell Diploid' floral fragrance is comprised of 13 volatile benzenoids/phenylpropanoids derived from the aromatic amino acid phenylalanine. Several genes involved in the direct synthesis of individual floral volatile benzenoid/phenylpropanoid (FVBP) compounds, i.e. at the end of the pathway, have been isolated and characterized in petunia through reverse genetic and...

Université de Fribourg

Starch granule biosynthesis in Arabidopsis is abolished by removal of all debranching enzymes but restored by the subsequent removal of an endoamylase

Streb, Sebastian ; Delatte, Thierry ; Umhang, Martin ; Eicke, Simona ; Schorderet, Martine ; Reinhardt, Didier ; Zeeman, Samuel C.

In: The Plant Cell, 2009, vol. 20, p. 3448-3466

Several studies have suggested that debranching enzymes (DBEs) are involved in the biosynthesis of amylopectin, the major constituent of starch granules. Our systematic analysis of all DBE mutants of Arabidopsis thaliana demonstrates that when any DBE activity remains, starch granules are still synthesized, albeit with altered amylopectin structure. Quadruple mutants lacking all four DBE proteins...

Université de Fribourg

A transgenic dTph1 insertional mutagenesis system for forward genetics in mycorrhizal phosphate transport of Petunia

Wegmüller, Sarah ; Svistoonoff, Sergio ; Reinhardt, Didier ; Stuurman, Jeroen ; Amrhein, Nikolaus ; Bucher, Marcel

In: The Plant Journal, 2008, vol. 54, no. 6, p. 1115 - 1127

The active endogenous dTph1 system of the Petunia hybrida mutator line W138 has been used in several forward-genetic mutant screens that were based on visible phenotypes such as flower morphology and color. In contrast, defective symbiotic phosphate (Pi) transport in mycorrhizal roots of Petunia is a hidden molecular phenotype as the symbiosis between plant roots and fungi takes place...

Université de Fribourg

A petunia mutant affected in intracellular accommodation and morphogenesis of arbuscular mycorrhizal fungi

Reddy, Sekhara ; Schorderet, Martine ; Feller, Urs ; Reinhardt, Didier

In: The Plant Journal, 2007, vol. 51, no. 5, p. 739-750

The regulation of the arbuscular mycorrhizal (AM) symbiosis is largely under the control of a genetic programme of the plant host. This programme includes a common symbiosis signalling pathway that is shared with the root nodule symbiosis. Whereas this common pathway has been investigated in detail, little is known about the mycorrhiza-specific regulatory steps upstream and downstream of the...

Université de Fribourg

Programming good relations - development of the arbuscular mycorrhizal symbiosis

Reinhardt, Didier

In: Current Opinion in Plant Biology, 2007, vol. 10, no. 1, p. 98–105

The majority of plants live in symbiotic associations with fungi or bacteria that improve their nutrition. Critical steps in a symbiosis are mutual recognition and subsequently the establishment of an intimate association, which involves the penetration of plant tissues and, in many cases, the invasion of individual host cells by the microbial symbiont. Recent advances revealed that in the...

Université de Fribourg

Regulation of phyllotaxis

Reinhardt, Didier

In: International Journal of Developmental Biology, 2005, vol. 49, p. 539

Plant architecture is characterized by a high degree of regularity. Leaves, flowers and floral organs are arranged in regular patterns, a phenomenon referred to as phyllotaxis. Regular phyllotaxis is found in virtually all higher plants, from mosses, over ferns, to gymnosperms and angiosperms. Due to its remarkable precision, its beauty and its accessibility, phyllotaxis has for centuries been...

Université de Fribourg

Microsurgical and laser ablation analysis of leaf positioning and dorsoventral patterning in tomato

Reinhardt, Didier ; Frenz, Martin ; Mandel, Therese ; Kuhlemeier, Cris

In: Development, 2005, vol. 132, p. 15

Leaves are arranged according to regular patterns, a phenomenon referred to as phyllotaxis. Important determinants of phyllotaxis are the divergence angle between successive leaves, and the size of the leaves relative to the shoot axis. Young leaf primordia are thought to provide positional information to the meristem, thereby influencing the positioning of new primordia and hence the divergence...