|
|
|
|
Press release.
28/03/2010
Unlocking the secrets of the black Perigord truffle: Scientists sequence genome, make strides in understanding the workings of the world’s most valued mushroom
INRA - CEA - CNRS - Nancy University - University of the Mediterranean
A French-Italian consortium coordinated by a team from INRA-Nancy, and with the involvement of Genoscope[1], CNRS, and the Universities of Lorraine and the Mediterranean have published an article on sequencing and decoding the genome of Tuber melanosporum, the highly prized black Perigord truffle. This feat allows scientists to have a better grasp of the biology of the species, its formation, and how the symbiosis between tree and mushroom evolves. The black Perigord truffle was selected for sequencing owing to its agricultural and cultural importance. The full paper appears in the NATURE advance online publication of 28 March 2010.
|
| |
After 5 years of hard work, researchers have finally managed to decode the genome of the truffle, an edible mushroom, for the first time. The French-Italian consortium of 50 scientists, coordinated by INRA, sequenced the genome of T. melanosporum in 2007 at the Genoscope using a line taken from a truffle harvested in Provence. The additional steps of assembling the initial raw sequences were then carried out for two more years, using finely detailed analysis of the truffle genome in the French laboratories of INRA, CNRS, CEA, the universities of Lorraine and the Mediterranean, and their Italian counterparts in Turin, Parma, Perugia, Urbina, Rome, and l’Aquila. Their work was completed by the study of the genes expressed during truffle formation and mycorrhizal symbiosis[2] in the tree’s roots.
Truffles are the result of a union between the underground filaments of T. melanosporum and the root branches of certain trees such as oaks. This relationship gives rise to mycorrhiza, symbiotic organs halfway between mushroom and root. Truffles have the largest known mushroom genome with 125 million base pairs. This astonishing figure is explained by the presence of repeated sequences (58%) whose impact on the diversity of the species is currently under study. The genome contains 7500 protein-coding genes, about 6000 of which are similar to those found in other mushroom species. Nonetheless, several hundred genes are unique to the truffle and play a fundamental role in mushroom formation and symbiosis with the host plant. Studying them will reveal the mechanisms behind the formation of this peculiar underground fructification[3].
Key results in understanding the evolution of mycorrhizal symbiosis
Comparative analysis of the truffle genome with that of Laccaria, another recently-sequenced symbiotic mushroom[4], revealed that their genomes were organised very differently, as were the mechanisms used to communicate and interact with their plant hosts. These discoveries demonstrated the extraordinary diversity in the manner by which symbiotic mushrooms interact with their partners, using different molecular toolboxes. Scientists now need to study the genomes of other symbiotic mushrooms so they can determine the flexibility and diversity of molecular processes involved in the interaction. Results regarding this symbiosis will help researchers understand other relationships between trees and mushrooms that were put in place more than 200 million years ago.
Using DNA fingerprints to “type” geographic origin
The relevance of the study goes beyond the purely academic. Full sequencing of the black Perigord truffle genome has also allowed the development of high-throughput diagnostic tools for genetic polymorphism of this valuable product. For centuries, pronounced variations in the organoleptic properties of truffles have been noted, depending on the regions they came from (Perigord, Provence, etc.), soil type, and maturity level. DNA sequencing also made it possible to spot several thousand genetic markers in the genome. About a dozen of these are currently being used to create a DNA fingerprint file of some fifty populations of Tuber melanosporum from Italy, Spain, and France. The DNA fingerprints make it easier to carry out “typing” of the geographic origin of harvested truffles, and allow the use of product certification and fraud detection tools[5]. Moreover, knowledge of the mechanisms behind the sexual compatibility of truffles should pave the way for better management of genetic diversity in truffle beds, by choosing the sex of truffles inoculated on tree roots.
Gaining a better understanding of the aromatic characteristics of truffles
Genome analysis confirmed that allergenic compounds and mycotoxins were absent from this centuries-old delicacy. The study of genes expressed during truffle formation revealed strong activity of biosynthetic pathways for volatile sulphur compounds and aldehydes that contribute to the coveted aromas of these “black diamonds”. This knowledge of the genetic characteristics of aroma formation will allow the selection of truffle strains with optimal organoleptic properties and the development of diagnostic tools that will help truffle growers make objective choices.
[1] Genoscope, Genome Institute, Life Sciences Division, French Atomic Energy Commission, Evry.
[2] Mycorrhizal symbiosis refers to the association between fungi and plant roots. The fungi help the plants extract nutrients from the soil. In return, the plants provide fungi with energy that they cannot derive from the sun by themselves.
[3] Fructification refers to the mushroom organ than carries the spores, which complete the life cycle; in this case, the truffle.
[4] F. Martin et al. "The genome of Laccaria bicolor provides insights into mycorrhizal symbiosis", NATURE, 06-03-2008
[5] See the Press Info item of 14/12/2005: «Truffles: increasingly rare and expensive... and beware of fraud! »
…………………………………
>> The entire truffle genetic sequence is available via the following sites:
Genoscope: www.genoscope.cns.fr/tuber
INRA: http://mycor.nancy.inra.fr/IMGC/TuberGenome/
>> Reference: "Périgord black truffle genome uncovers evolutionary origins and mechanisms of symbiosis", NATURE, 28-03-2010, http://dx.doi.org/ ; doi : 10.1038/nature08867.
Francis Martin1, Annegret Kohler1, Claude Murat1, Raffaella Balestrini2, Pedro M. Coutinho3, Olivier Jaillon4–6, Barbara Montanini7, Emmanuelle Morin1, Benjamin Noel4–6, Riccardo Percudani7, Bettina Porcel4–6, Andrea Rubini8, Antonella Amicucci9, Joelle Amselem10, Véronique Anthouard4–6, Sergio Arcioni8, François Artiguenave4–6, Jean-Marc Aury4–6, Paola Ballario11, Angelo Bolchi7, Andrea Brenna11, Annick Brun1, Marc Buée1, Brandi Cantarel3, Gérard Chevalier12, Arnaud Couloux4–6, Corinne Da Silva4–6, France Denoeud4–6, Sébastien Duplessis1, Stefano Ghignone2, Benoît Hilselberger1,10, MircoIotti13, Benoît Marçais1, Antonietta Mello2, Michele Miranda14, Giovanni Pacioni15, Hadi Quesneville10, Claudia Riccioni8, Roberta Ruotolo7, Richard Splivallo16, Vilberto Stocchi9, Emilie Tisserant1, Arturo Roberto Viscomi7, Alessandra Zambonelli13, Elisa Zampieri2, Bernard Henrissat3, Marc-Henri Lebrun17, Francesco Paolocci8, Paola Bonfante2, Simone Ottonello7 & Patrick Wincker4–6
1INRA, UMR 1136, INRA-Nancy Université, Interactions Arbres/Microorganismes, 54280 Champenoux, France. 2Istituto per la Protezione delle Piante del CNR, sez. di Torino and Dipartimento di Biologia, Università degli Studi di Torino, Viale Mattioli, 25, 10125 Torino, Italy. 3Architecture et Fonction des Macromolécules Biologiques, UMR 6098 CNRS Universités Aix-Marseille I & II, 13288 Marseille, France. 4CEA, IG, Genoscope, 2 rue Gaston Crémieux CP5702, F-91057 Evry, France. 5CNRS, UMR 8030, 2 rue Gaston Crémieux, CP5706, F-91057 Evry, France. 6Université d’Evry, F-91057 Evry, France. 7Dipartimento di Biochimica e Biologia Molecolare, Università degli Studi di Parma, Viale G.P. Usberti 23/A, 43100 Parma, Italy. 8CNR-IGV Istituto di Genetica Vegetale, Unita` Organizzativa di Supporto di Perugia, via Madonna Alta, 130, 06128 Perugia, Italy. 9Dipartimento di Scienze Biomolecolari, Universita` degli Studi di Urbino, Via Saffi 2 - 61029 Urbino (PU), Italy. 10INRA, Unité de Recherche Génomique Info, Route de Saint-Cyr, 78000 Versailles, France. 11Dipartimento di Genetica e Biologia Molecolare & IBPM (CNR), Università La Sapienza, Roma, Piazzale, A. Moro 5, 00185 Roma, Italy. 12INRA, UMR Amélioration et Santé des Plantes, INRA-Université Blaise Pascal, INRA – Clermont-Theix, 63122 Saint-Genes-Champanelle, France. 13Dipartimento di Protezione e Valorizzazione Agroalimentare, Università degli Studi
di Bologna, 40 126 Bologna, Italy. 14Dipartimento di Biologia di Base ed Applicata, 15Dipartimento di Scienze Ambientali, Universita` degli Studi dell’Aquila, Via Vetoio Coppito 1 – 67100 L’Aquila, Italy. 16University of Goettingen, Molecular Phytopathology and Mycotoxin Research, Grisebachstrasse 6, D-37077 Goettingen, Germany. 17INRA, UMRBIOGER-CPP, INRA Grignon, av Lucien Brétignières - 78 850 Thiverval Grignon, France.
|
| |
|
Written by :
INRA press service, phone: +33 (0)1 42 75 91 69
Mathilde Maufras, tel: + 33 (0)1 42 75 91 69 / presse@inra.fr or Ana Poletto, tel: +33 (0)3 83 39 73 41 / ana.poletto@nancy.inra.fr
Contacts :
Scientific Contacts:
Francis MARTIN
tel.: +33 3 83 39 40 80 or fmartin@nancy.inra.fr
Claude Murat
tel.: + 33 3 83 39 40 40 or claude.murat@nancy.inra.fr
Joint Research Unit for Tree/Microorganism Interactions
INRA-Nancy-Université-UHP,
Forest, Grassland and Freshwater Ecology Division,
INRA Nancy.
|
|
|
|
Search :
