J. André Fortin

Bio: J. André Fortin is an academic researcher from Laval University. The author has contributed to research in topics: Laccaria bicolor & Ectomycorrhizae. The author has an hindex of 26, co-authored 58 publications receiving 2309 citations.

Identification of indigenous and introduced symbiotic fungi in ectomycorrhizae by amplification of nuclear and mitochondrial ribosomal DNA

Abstract: We used the polymerase chain reaction (PCR) to amplify specific regions of the nuclear and mitochondrial genomes of fungi using DNA extracted from pure cultures as well as that directly from ectomy...

Arbuscular mycorrhiza on root-organ cultures

Abstract: The study of arbuscular mycorrhizal (AM) fungi and the AM symbiosis formed with host plant roots is com- plicated by the biotrophic and hypogeous nature of the mycobionts involved. To overcome this, several attempts have been made during the last three decades to obtain this symbiosis in vitro. The use of root-organ cultures has proved particularly successful. In this review, we describe the method by which root-organ cultures (transformed and nontransformed) have been obtained, together with the choice of host species, inoculation techniques, and culture me - dia. We also outline the potential use of continuous cultures and cryopreservation of in vitro produced spores for long-term germ plasm storage. Furthermore, this review highlights the considerable impact that in vitro root-organ cul - tures have had on studies of AM fungal morphology, taxonomy, and phylogeny and how they have improved our un- derstanding of the processes leading to root colonization and development of the extraradical mycelium. This is supported by a summary of some of the most important findings, regarding this symbiosis, that have been made at the physiological, biochemical, and molecular levels. We also summarize results from studies between AM fungi and cer- tain pathogenic and nonpathogenic soil microorganisms. We describe some of the limitations of this in vitro system and propose diverse avenues of AM research that can now be undertaken, including the potential use of a similar sys- tem for ectomycorrhizal research.

In Vitro Culture of Mycorrhizas

Abstract: Preface Part I State of the Art 1 In vitro culture of mycorrhizas J.A. Fortin, S. Declerck & D.G. Strullu Part II Systematics 2 The Monoxenic culture of arbuscular mycorrhizal fungi as a tool for germplasm collection S. Declerck, S. Seguin & Y. Dalpe 3 The Monoxenic culture of arbuscular mycorrhizal fungi as a tool for systematics and biodiversity Y. Dalpe, S. Cranenbrouck , S. Seguin & S. Declerck 4 Life cycle of Glomus species in monoxenic culture Y. Dalpe, F.A. de Souza & S. Declerck 5 Life history strategies in Gigasporaceae : insight from monoxenic culture F.A. de Souza, Y. Dalpe, S. Declerck, I. de la Providencia & N. Sejalon Delmas Part III In Vitro Development and Physiology of Glomeromycetes 6 Environmental factors that affect presymbiotic hyphal growth and branching of arbuscular mycorrhizal fungi G. Nagahashi & D. Douds Jr 7 Breaking myths on arbuscular mycorrhizas in vitro biology B. Bago & C. Cano 8 Host and non-host impact on the physiology of the arbuscular mycorrhizal symbiosis H. Vierheilig & B. Bago 9 Carbon metabolism, lipid composition and metabolism in arbuscular mycorrhizal fungi A. Grandmougin-Ferjani, J. Fontaine & R. Durand 10 Monoxenic culture as a tool to study the effects of the arbuscular mycorrhizal symbiosis on the physiology of micropropagated plantlets in vitro and ex vitro Y. Desjardin C. Hernandez-Sebastia & Y. Piche 11 Uptake, assimilation and translocation of mineral elements in monoxenic cultivation systems G. Rufyikiri, N. Kruyts, S Declerck, Y. Thiry, B. Delvaux, H. Dupre de Boulois & E.J. Joner 12 Interaction of arbuscular mycorrhizal fungi with soil borne pathogens and non-pathogenic rhizosphere micro-organisms M. St Arnaud & A. Elsen Part IV Root Organ Culture of EctomycorrhizalFungi 13 Cistus incanus root-organ cultures: a valuable tool for studying mycorrhizal associations A.P. Coughlan & Y. Piche 14 Cultivation of edible ectomycorrhizal fungi by in vitro mycorrhizal synthesis G. Giomaro, D. Sisti & A. Zambonelli Part V Root Organ Culture of Other Fungal Symbiosis 15 Geosiphon pyriformis - a glomeromycotan soil fungus forming endosymbiosis with cyanobacteria A. Schussler & E. Wolf 16 Sebacinaceae: culturable mycorrhiza-like endosymbiotic fungi and their interaction with non-transformed and transformed roots R. Prasad, G.H. Pham, R. Kumari, A. Singh, V. Yadav, M. Sachdev, A.P. Garg, T. Peskan, S. Hehl, I. Sherameti, R. Oemuller & A. Varma Part VI Biotechnology 17 Large scale inoculum production of arbuscular mycorrhizal fungi on root organs and inoculation strategies A. Adholeya, P. Tiwari & R. Singh Part VII Methodology 18 Methodologies for in vitro cultivation of arbuscular mycorrhizal fungi with root organs S. Cranenbrouck, L. Voets, C. Bivort, L. Renard, D.G. Strullu & S. Declerck

Frequency and diversity of ectomycorrhizal and saprophytic macrofungi in the Laurentide Mountains of Quebec

Abstract: Total macro fungus frequency in closed forest associations of the Laurentide Mountains varied little (147 – 185 %) from one to another. The macrofungal flora of the deciduous forest was composed ma...

Trapping of phosphate solubilizing bacteria on hyphae of the arbuscular mycorrhizal fungus Rhizophagus irregularis DAOM 197198

Abstract: A simple method is described for trapping phosphate solubilizing bacteria (PSB) strongly attached to the hyphae of the arbuscular mycorrhizal fungus (AMF) Rhizophagus irregularis (Ri). Bacteria were isolated from the hyphosphere of mycorrhizal leek plants growing on Turface previously inoculated with soil suspensions, obtained from the mycorrhizosphere of mycorrhizal plants growing in agricultural settings or maple forests in Quebec, Canada. Among the best PSB strongly attached to the hyphae of Ri, 26 isolates belonged to Burkholderia spp. and one was identified as Rhizobium miluonense. Four hyphobacteria exhibiting high potential of inorganic and organic P mobilization were further compared with four equivalent mycorrhizobacteria directly isolated from mycorrhizospheric soils sampled. In general, hyphobacteria were superior in mobilizing P from hydroxyapatite and from a low reactivity igneous phosphate rock from Quebec. Release of gluconic acid or the product of its oxidation 2-ketogluconic acid, are the main mechanisms involved in P solubilization. In a two compartments Petri plate system, Ri extraradical hyphal exudates, supported PSB growth and activity. In the absence of PSB Ri showed a negligible P solubilization activity. In the presence of PSB a substantial increase in P mobilization was observed, and the superiority of hyphobacterial activity was also observed under this system. Our results suggest that in developing a bioinoculant based on selected PSB, their interaction with AMF hyphae should not be overlooked.

ITS primers with enhanced specificity for basidiomycetes--application to the identification of mycorrhizae and rusts.

Abstract: We have designed two taxon-selective primers for the internal transcribed spacer (ITS) region in the nuclear ribosomal repeat unit. These primers, ITS1-F and ITS4-B, were intended to be specific to fungi and basidiomycetes, respectively. We have tested the specificity of these primers against 13 species of ascomycetes, 14 of basidiomycetes, and 15 of plants. Our results showed that ITS4-B, when paired with either a 'universal' primer ITS1 or the fungal-specific primer ITS1-F, efficiently amplified DNA from all basidiomycetes and discriminated against ascomycete DNAs. The results with plants were not as clearcut. The ITS1-F/ITS4-B primer pair produced a small amount of PCR product for certain plant species, but the quantity was in most cases less than that produced by the 'universal' ITS primers. However, under conditions where both plant and fungal DNAs were present, the fungal DNA was amplified to the apparent exclusion of plant DNA. ITS1-F/ITS4-B preferential amplification was shown to be particularly useful for detection and analysis of the basidiomycete component in ectomycorrhizae and in rust-infected tissues. These primers can be used to study the structure of ectomycorrhizal communities or the distribution of rusts on alternate hosts.

Development of primer sets designed for use with the PCR to amplify conserved genes from filamentous ascomycetes.

Abstract: We constructed nine sets of oligonucleotide primers on the basis of the results of DNA hybridization of cloned genes from Neurospora crassa and Aspergillus nidulans to the genomes of select filamentous ascomycetes and deuteromycetes (with filamentous ascomycete affiliations). Nine sets of primers were designed to amplify segments of DNA that span one or more introns in conserved genes. PCR DNA amplification with the nine primer sets with genomic DNA from ascomycetes, deuteromycetes, basidiomycetes, and plants revealed that five of the primer sets amplified a product only from DNA of the filamentous ascomycetes and deuteromycetes. The five primer sets were constructed from the N. crassa genes for histone 3, histone 4, beta-tubulin, and the plasma membrane ATPase. With these five primer sets, polymorphisms were observed in both the size of and restriction enzyme sites in the amplified products from the filamentous ascomycetes. The primer sets described here may provide useful tools for phylogenetic studies and genome analyses in filamentous ascomycetes and deuteromycetes (with ascomycete affiliations), as well as for the rapid differentiation of fungal species by PCR.

Mycorrhizas and nutrient cycling in ecosystems – a journey towards relevance?

Abstract: Progress towards understanding the extent to which mycorrhizal fungi are involved in the mobilization of nitrogen (N) and phosphorus (P) from natural substrates is reviewed here. While mycorrhiza research has emphasized the role of the symbiosis in facilitation of capture of these nutrients in ionic form, attention has shifted since the mid-1980s to analysing the mycorrhizal fungal abilities to release N and P from the detrital materials of microbial faunal and plant origins, which are the primary sources of these elements in terrestrial ecosystems. Ericoid, and some ectomycorrhizal fungi have the potential to be directly involved in attack both on structural polymers, which may render nutrients inaccessible, and in mobilization of N and P from the organic polymers in which they are sequestered. The advantages to the plant of achieving intervention in the microbial mobilization-immobilization cycles are stressed. While the new approaches may initially lack the precision achieved in studies of readily characterized ionic forms of N and P, they do provide insights of greater ecological relevance. The results support the hypothesis that selection has favoured ericoid and ectomycorrhizal systems with well developed saprotrophic capabilities in those ecosystems characterized by retention of N and P as organic complexes in the soil. The need for further investigation of the abilities of arbuscular mycorrhizal fungi to intervene in nutrient mobilization processes is stressed.

Reciprocal Rewards Stabilize Cooperation in the Mycorrhizal Symbiosis

Abstract: Plants and their arbuscular mycorrhizal fungal symbionts interact in complex underground networks involving multiple partners. This increases the potential for exploitation and defection by individuals, raising the question of how partners maintain a fair, two-way transfer of resources. We manipulated cooperation in plants and fungal partners to show that plants can detect, discriminate, and reward the best fungal partners with more carbohydrates. In turn, their fungal partners enforce cooperation by increasing nutrient transfer only to those roots providing more carbohydrates. On the basis of these observations we conclude that, unlike many other mutualisms, the symbiont cannot be "enslaved." Rather, the mutualism is evolutionarily stable because control is bidirectional, and partners offering the best rate of exchange are rewarded.

Fungal Molecular Systematics

Abstract: The fungi comprise both members of the kingdom Fungi as we now recognize it (Ascomycota, Basidiomycota, Zygomycota, and Chytridiomycota) and fungal-like protists such as the Oomycota and the cellular and acellular slime molds (Myxomycota and Acrasiomycota). Treating this admittedly polyphyletic assemblage as a group is useful because these organisms often fill rather similar roles within ecosystems, and they have traditionally been studied almost exclusively by mycologists and plant pathologists. Throughout this review, Fungi will refer to the Kingdom, fungi to the organisms studied by mycologists. The fungi, as thus defined, are of great importance for the following reasons: (a) They are the primary decomposers in all terrestrial ecosystems; (b) they are important symbiotic associates of vascular plants both in mutualistic and parasitic relationships; (c) they constitute the overwhelming majority of plant pathogens and as such have a tremendous eco-