Silvia Perotto

• PhD
• Professor (Full) at University of Turin

Like other plant-microbe symbioses, the establishment of orchid mycorrhiza (ORM) is likely to require specific communication and metabolic adjustments between the two partners. However, while modulation of plant and fungal metabolism has been investigated in fully established mycorrhizal tissues, the molecular changes occurring during the pre-symbi...

Some heavy metal tolerant fungal isolates capable of forming ericoid mycorrhiza can also confer increased metal tolerance to the host plant. One of these fungal isolates, Oidiodendron maius Zn, has been characterized and a few molecular mechanisms underlying its metal tolerant phenotype have been identified. Here, we investigate the genomic diverge...

– Most green orchids associate with orchid mycorrhizal (OrM) fungi belonging to the ′rhizoctonia′ complex, a polyphyletic group of Tulasnellaceae, Ceratobasidiaceae and Serendipitaceae (Agaricomycotina), which are generally assumed to live as saprotrophs in soil. However, OrM rhizoctonias were rarely detected by metabarcoding in soil around orchid...

In nature, germination of orchid seeds and early plant development rely on a symbiotic association with orchid mycorrhizal (ORM) fungi. These fungi provide the host with the necessary nutrients and facilitate the transition from embryos to protocorms. Despite recent advances in omics technologies, our understanding of this symbiosis remains limited...

Arbuscular (AM) and orchid (OrM) mycorrhiza are the most widespread mycorrhizal symbioses among flowering plants, formed by distinct fungal and plant species. They are both endosymbioses because the fungal hyphae can enter inside the plant cell to develop intracellular fungal structures that are surrounded by the plant membrane. The symbiotic plant...

Orchid mycorrhiza (OM) represents an unusual symbiosis between plants and fungi because in all orchid species carbon is provided to the host plant by the mycorrhizal fungus at least during the early stages of orchid development, named a protocorm. In addition to carbon, orchid mycorrhizal fungi provide the host plant with essential nutrients such a...

In nature, orchid seed germination and early development both require an interaction between the plant and some symbiotic fungi capable of forming orchid mycorrhizae (OM). In recent years, the use of -omics approaches has been instrumental to start elucidating the molecular mechanisms of this important symbiosis. Transcriptomics is one of the most...

Earth’s life may have originated as self-replicating RNA. Some of the simplest current RNA replicators are RNA viruses, defined by linear RNA genomes encoding an RNA-dependent RNA polymerase (RdRP), and subviral agents with single-stranded, circular RNA genomes, such as viroids encoding paired self-cleaving ribozymes. Amongst a massive expansion of...

Plants harbor in their external surfaces and internal tissues a highly diverse and finely structured microbial assembly, the microbiota. Each plant compartment usually represents a unique ecological niche hosting a distinct microbial community and niche differentiation, which may mirror distinct functions of a specialized microbiota, has been mainl...

The environmental distribution of non-obligate orchid mycorrhizal (OM) symbionts belonging to the ‘rhizoctonia’ complex remains elusive. Some of these fungi, indeed, are undetectable in soil outside the host rhizosphere. A manipulation experiment was performed to assess the importance of neighbouring non-orchid plants and soil as possible reservoir...

The study of orchid mycorrhizal interactions is particularly complex because of the peculiar life cycle of these plants and their diverse trophic strategies. Here, transcriptomics has been applied to investigate gene expression in the mycorrhizal roots of Limodorum abortivum, a terrestrial mixotrophic orchid that associates with ectomycorrhizal fun...

Orchids are highly dependent on symbiotic microorganisms during their entire life cycle. Whereas an important role in orchid seed germination and early plant development is well established for mycorrhizal fungi, the influence of endophytic bacteria on orchid growth has been less investigated. Here, we report the isolation of endophytic bacteria fr...

The endophytic microbiota can establish mutualistic or commensalistic interactions within the host plant tissues. We investigated the bacterial endophytic microbiota in three species of Mediterranean orchids (Neottia ovata, Serapias vomeracea, and Spiranthes spiralis) by metabarcoding of the 16S rRNA gene. We examined whether the different orchid s...

Mycorrhizal fungi are mutualists that play crucial roles in nutrient acquisition in terrestrial ecosystems. Mycorrhizal symbioses arose repeatedly across multiple lineages of Mucor-omycotina, Ascomycota, and Basidiomycota. Considerable variation exists in the capacity of mycorrhizal fungi to acquire carbon from soil organic matter. Here, we present...

Mutualistic plant-associated fungi are recognized as important drivers in plant evolution, diversity and health. The discovery that mycoviruses can take part and play important roles in symbiotic tripartite interactions has prompted us to study the viromes associated with a collection of ericoid and orchid mycorrhizal (ERM and ORM, respectively) fu...

Orchids form endomycorrhizal associations with fungi mainly belonging to basidiomycetes. The molecular events taking place in orchid mycorrhiza are poorly understood, although the cellular changes necessary to accommodate the fungus and to control nutrient exchanges imply a modulation of gene expression. Here, we used proteomics and transcriptomics...

All orchids rely on mycorrhizal fungi for organic carbon, at least during early development. In fact, orchid seed germination leads to the formation of a protocorm, a heterotrophic postembryonic structure colonized by intracellular fungal coils, thought to be the site of nutrient transfer. The molecular mechanisms underlying mycorrhizal interaction...

Mycorrhizas are among the most important biological interkingdom interactions, as they involve ~340,000 land plants and ~50,000 taxa of soil fungi. In these mutually beneficial interactions, fungi receive photosynthesis-derived carbon and provide the host plant with mineral nutrients such as phosphorus and nitrogen in exchange. More than 150 years...

Photosynthetic orchids associate with mycorrhizal fungi that can be mostly ascribed to the “rhizoctonia” species complex. Rhizoctonias’ phylogenetic diversity covers a variety of ecological/nutritional strategies that include, beside the symbiosis establishment with host plants, endophytic and pathogenic associations with non-orchid plants or sapro...

The success of Ericaceae in stressful habitats enriched in heavy metals has been ascribed to the distinctive abilities of their mycorrhizal fungal partners to withstand heavy metal stress and to enhance metal tolerance in the host plant. Whereas heavy metal tolerance has been extensively investigated in some ericoid mycorrhizal (ERM) fungi, the mol...

Fungi produce a wide variety of biologically active secondary metabolites, a large proportion of them being polyketides, a group of compounds characterized by a great complexity and structural diversity. Fungal polyketides are produced by polyketide synthases (PKSs), very large multifunctional iterative enzymes. Several functions have been attribut...

Fungi produce a wide variety of biologically acIve secondary metabolites, a large proportion of them being polyketides, a group of compounds characterized by a great complexity and structural diversity. Polyketides are produced by polyketide synthases (PKSs), very large multi-functional iterative enzymes. Several functions have been attributed to f...

The cysteine-rich PLAC8 domain of unknown function occurs in proteins found in most Eukaryotes. PLAC8-proteins play important yet diverse roles in different organisms, such as control of cell proliferation in animals and plants or heavy metal resistance in plants and fungi. Mammalian Onzin can be either pro-proliferative or pro-apoptotic, depending...

Protein domains are structurally and functionally distinct units responsible for particular protein functions or interactions. Although protein domains contribute to the overall protein function(s) and can be used for protein classification, about 20% of protein domains are currently annotated as “domains of an unknown function” (DUFs). DUF 614, a...

Contents I. II. III. IV. V. VI. VII. References The genome of an organism bears the signature of its lifestyle, and organisms with similar life strategies are expected to share common genomic traits. Indeed, ectomycorrhizal and arbuscular mycorrhizal fungi share some genomic traits, such as the expansion of gene families encoding taxon‐specific sma...

In the past decade, laser microdissection (LMD) technology has been widely applied to plant tissues, highlighting the role of different cell-type populations during plant–microbe interactions. In this chapter, a method to apply the LMD approach to study gene expression in specific cell-type populations of orchid mycorrhizal protocorms and roots is...

Mutualistic and pathogenic plant-colonizing fungi use effector molecules to manipulate the host cell metabolism to allow plant tissue invasion. Some small secreted proteins (SSPs) have been identified as fungal effectors in both ectomycorrhizal and arbuscular mycorrhizal fungi, but it is currently unknown whether SSPs also play a role as effectors...

Several studies have investigated soil microbial biodiversity, but understanding of the mechanisms underlying plant responses to soil microbiota remains in its infancy. Here, we focused on tomato ( Solanum lycopersicum ), testing the hypothesis that plants grown on native soils display different responses to soil microbiotas. Using transcriptomics,...

Some soil fungi in the Leotiomycetes form ericoid mycorrhizal ( ERM ) symbioses with Ericaceae. In the harsh habitats in which they occur, ERM plant survival relies on nutrient mobilization from soil organic matter ( SOM ) by their fungal partners. The characterization of the fungal genetic machinery underpinning both the symbiotic lifestyle and SO...

Mutualistic and pathogenic plant-colonizing fungi use effector molecules to manipulate the host cell metabolism to allow plant tissue invasion. Some small secreted proteins (SSPs) have been identified as fungal effectors in both ectomycorrhizal and arbuscular mycorrhizal fungi, but it is currently unknown whether SSPs also play a role as effectors...

Orchid mycorrhizal protocorms and roots are heterogeneous structures composed of different plant cell-types, where cells colonized by intracellular fungal coils (the pelotons) are close to non-colonized plant cells. Moreover, the fungal coils undergo rapid turnover inside the colonized cells, so that plant cells containing coils at different develo...

Orchids depend on mycorrhizal fungi for their nutrition, at least in the early stages of their growth and development, and in many cases throughout the life. In spite of the increasing number of studies describing fungal diversity in orchids, there is still more to be learnt about the identity of fungal partners and specificity in orchid mycorrhiza...

Mycorrhizal fungi are essential for the survival of orchid seedlings under natural conditions. The distribution of these fungi in soil can constrain the establishment and resulting spatial arrangement of orchids at the local scale, but the actual extent of occurrence and spatial patterns of orchid mycorrhizal (OrM) fungi in soil remain largely unkn...

Orchids are highly dependent on their mycorrhizal fungal partners for nutrient supply, especially during early developmental stages. In addition to organic carbon, nitrogen (N) is probably a major nutrient transferred to the plant because orchid tissues are highly N‐enriched. We know almost nothing about the N form preferentially transferred to the...

Plant growth and development can be influenced by mutualistic and non-mutualistic microorganisms. We investigated the ability of the ericoid endomycorrhizal fungus Oidiodendron maius to influence growth and development of the non-host plant Arabidopsis thaliana. Different experimental setups (non-compartmented and compartmented co-culture plates) w...

A. thaliana plants growth in the tripartite plate system with a CO2 saturated trap compound. (a) A. thaliana plants growth in control plates (At) and in plates added with a CO2 trap compound, Ba(OH)2*8H2O (At-B) and with the same compound saturated with CO2 (At-B-CO2 saturated); (b) plant biomass measurements (roots—grey bars—and aboveground portio...

GUS assay results for the A. thaliana DR5::GUS line plants. (a) A. thaliana DR5::GUS control plants, (b) A. thaliana DR5::GUS plants co-cultivated with the O. maius WT (b) and with the O. maius GOGAT mutant (c). Staining was performed on aboveground and belowground portions of A. thaliana fresh tissues and stained tissues were observed and photogra...

A. thaliana plants development in the absence/presence of glutamate. Five days old A. thaliana plants grown for 4 days on the MS medium (C) and on the MS medium added with 25.6 mM Na-glutamate (Glu) using the non-compartmented square plate setup. Note the shorter and more branched root in the presence of glutamate. (TIF)

O. maius GOGAT mutant—A. thaliana co-cultivation experiments in the tripartite plate system. (a) Control plants and plant-fungus co-cultures 15 days after inoculation; (b) same as in (a) but plates were added with a VOCs trap compound (activated charcoal, AC) in the third compartment; (c) same as in (a) but plates were added with a CO2 trap compoun...

Time course of the A. thaliana plants development in the absence/presence of the O. maius WT and of the O. maius GOGAT mutant. The clumped root phenotype started forming after 6 days of plant-fungus co-cultivation only in the presence of the O. maius WT strain. (TIF)

Plant and fungal biomass in the bipartite plates. Plant and fungal biomasses were measured in the bipartite plates and a correlation analysis was performed using the Pearson’s correlation test. (DOCX)

Orchid mycorrhizas (OM) are symbiotic interactions between fungi and terrestrial, epiphytic or lithophytic species of the Orchidaceae. In the association, fungal hyphae enter parenchyma cells of germinating seeds, protocorms, seedlings or roots of adult plants, and form elaborate intracellular hyphal coils. The latter are known as pelotons, thought...

Ectomycorrhizal (ECM) fungi largely determine the element offer at the fungusroot interface, although they do not take over the plant nutrient uptake system. In complex forest soils, trees undoubtedly benefit from the well-adapted nutrient acquisition strategies evolved in the huge diversity of ECM fungi that occupy the numerous niches in the diffe...

Ericoid mycorrhizal plants dominate in harsh environments where nutrient-poor, acidic soil conditions result in a higher availability of potentially toxic metals. Although metal-tolerant plant species and ecotypes are known in the Ericaceae, metal tolerance in these plants has been mainly attributed to their association with ericoid mycorrhizal fun...

Mycorrhizae are symbiotic associations between soil fungi belonging to diverse taxa and the roots of about 90% of all terrestrial plant species. The mutualistic nature of these symbioses is based on the nutritional exchanges between the partners. However, the benefits to the plant partner are not limited to an improved mineral nutrition because the...

Although adaptive metal tolerance may arise in fungal populations in polluted soils, the mechanisms underlying metal-specific tolerance are poorly understood. Comparative proteomics is a powerful tool to identify variation in protein profiles caused by changing environmental conditions, and was used to investigate protein accumulation in a metal to...

To elucidate the genetic bases of mycorrhizal lifestyle evolution, we sequenced new fungal genomes, including 13 ectomycorrhizal (ECM), orchid (ORM) and ericoid (ERM) species, and five saprotrophs, which we analyzed along with other fungal genomes. Ectomycorrhizal fungi have a reduced complement of genes encoding plant cell wall–degrading enzymes (...

Mycorrhizal fungi are fundamental in orchid growth and metabolism and influence the distribution and rarity of these delicate plants. Fungal molecular systematics has been instrumental for the identification of orchid mycorrhizal symbionts because it overcomes the limits associated with in vitro isolation and morphological characterization of orchi...

Little is known on the molecular bases of plant - fungal interactions in orchid mycorrhiza. We developed a model system to investigate gene expression in mycorrhizal protocorms of Serapias vomeracea colonised by Tulasnella calospora. Our recent results with a small panel of genes as indicators of plant response to mycorrhizal colonization indicate...

Many adult orchids, especially photoautotrophic species, associate with a diverse range of mycorrhizal fungi, but little is known about the temporal changes that might occur in the diversity and functioning of orchid mycorrhiza during vegetative and reproductive plant growth. Temporal variations in the spectrum of mycorrhizal fungi and in stable is...

Fungi living in heavy metal polluted soils have evolved different cellular and molecular systems to adapt and survive in these harsh environments. Oidiodendron maius Zn is an ericoid mycorrhizal fungus previously shown to be highly tolerant to zinc thanks to antioxidative enzymes and membrane transporters. A novel gene, OmFCR1, was recently identif...

Mutualistic symbioses between plants and fungi are a widespread phenomenon in nature. Particularly in orchids, association with symbiotic fungi is required for seed germination and seedling development. During the initial stages of symbiotic germination, before the onset of photosynthesis, orchid protocorms are fully mycoheterotrophic. The molecula...

Orchids fully depend on symbiotic interactions with specific soil fungi for seed germination and early development. Germinated seeds give rise to a protocorm, a heterotrophic organ that acquires nutrients, including organic carbon, from the mycorrhizal partner. It has long been debated if this interaction is mutualistic or antagonistic. To investig...

Background and aims – Mycorrhizae have a pivotal impact on orchid growth and metabolism. We investigated the diversity of root fungal associates in Himantoglossum adriaticum H.Baumann, an endangered terrestrial orchid species with a central submediterranean distribution, growing in poor grassland, open woodland and garrigue. Methods – Fungal divers...

Living organisms establish complex networks of mutualistic and antagonistic interactions in nature, which impact strongly on their own survival and on the stability of the whole population. Fungi, in particular, can shape natural as well as man-managed ecosystems due to their ubiquitous occurrence and the range of interactions they establish with p...

Abstract: Identifying a soil core microbiome is crucial to appreciate the established microbial consortium, which is not usually subjected to change and, hence, possibly resistant/resilient to disturbances and a varying soil context. Fungi are a major part of soil biodiversity, yet the mechanisms driving their large-scale ecological ranges and dist...

Abstract: Identifying a soil core microbiome is crucial to appreciate the established microbial consortium, which is not usually subjected to change and, hence, possibly resistant/resilient to disturbances and a varying soil context. Fungi are a major part of soil biodiversity, yet the mechanisms driving their large-scale ecological ranges and dist...

##Assembly-Data-START## Assembly Method :: Geneious v. 5.3 Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##

##Assembly-Data-START## Assembly Method :: Geneious v. 5.3 Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##

##Assembly-Data-START## Assembly Method :: Geneious v. 5.3 Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##

##Assembly-Data-START## Assembly Method :: Geneious v. 5.3 Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##

The terrestrial orchid, Orchis pauciflora Ten., growing in poor grassland and garrigue of Central Mediterranean region, is local and rare and has been included in the red lists of several Italian regions. We investigated the diversity of fungal associates in O. pauciflora adult plants collected in two protected areas of Tuscany (Central Italy). Gen...

The physico-chemical properties of serpentine soils lead to strong selection of plant species. Whereas many studies have described the serpentine flora, little information is available on the fungal communities dwelling in these sites. Asbestos minerals, often associated with serpentine rocks, can be weathered by serpentine-isolated fungi, suggesti...

Hierarchical clustering representing the distance among the four substrates. The clustering was based on (A) the extractable fraction of cations, the distribution and representation of (B) ITS1 OTUs and (C) ITS2 OTUs within the four sites. See Materials and Methods section for the details of the analyses. (TIF)

ITS1 dominant OTUs. OTUs supported by at least 10 reads were ranked according to their abundance. (DOC)

Dominant taxa according to the ITS2 region sequencing. (DOC)

ITS2 dominant OTUs. OTUs supported by at least 10 reads were ranked according to their abundance. (DOC)

ITS1 and ITS2 blast results at genus level. The OTUs≥10 reads were grouped according to their taxon assignment at genus level and the number of ITS1 and ITS2 reads supporting each taxon is reported. (TIF)

Dominant taxa according to the ITS1 region sequencing. (DOC)

Primers used in the described experiments. (DOC)

Ericoid mycorrhizal (ERM) fungi are a diverse assemblage of symbiotic fungi that features culturable ascomycetes in the Helotiales and Onygenales, but also so far unculturable basidiomycetes in the Sebacinales. They form a distinct endomycorrhizal association with some plant genera in the Ericaceae. ERM plants dominate in heathlands characterised b...

We have assessed the identities of fungi associated with Orchis tridentata, an endangered orchid species growing in open woodland and poor grassland of Central and Southern Europe. Fungal diversity in ten O. tridentata adult individuals collected in two protected areas of Central Italy was analysed by means of morphological and molecular methods. S...

##Assembly-Data-START## Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##

##Assembly-Data-START## Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##