Arbuscular Mycorrhizal Fungi and their Value for Ecosystem Management

Arbuscular Mycorrhizal Fungi (AMF) are root obligate symbionts of nearly all the plants living on Earth. They are considered as living fossils: there are evidences that date back to 460 million years ago their presence on our planet. Taxonomically, they belong to the Glomeromycota phylum. They are found in roots of 80% of plant species and give and get back benefits to their partners, as happens in all mutual symbiotic relationships. They build up a bridge between plant and soil, growing their mycelia both inside and outside plant roots. AMF provide the plant with water, soil mineral nutrients (mainly phosphorus and nitrogen), and pathogen protection. In exchange, photosynthetic compounds are transferred to the fungus. Besides physiological benefits to the host-plant, AMF play an important ecological role. They are important in soil structuring thanks to their thick extraradical hyphal network able to aggregate soil particles. They help plants establish in degraded ecosystems (e.g. desert areas and mine spoils) and positively affect phytoremediation. They can influence processes (i.e. soil carbon sequestration) related to climate change. Last but not least, their belowground presence and diversity can positively affect the aboveground plant biodiversity and productivity. These roles played by AMF for the ecosystem functioning lead to consider them as key soil organisms. Therefore, every AMF aspect is extensively studied: from biological features, through biogeography and biodiversity, to phylogeny. [...]JRC.H.5-Land Resources Managemen

Native Arbuscular Mycorrhizal Fungi Characterization from Saline Lands in Arid Oases, Northwest China

Arbuscular mycorrhizal fungi (AMF) colonize land plants in almost every ecosystem, even in extreme conditions, such as saline soils. In the present work, we report the mycorrhizal capacity of rhizosphere soils collected in the dry desert region of the Minqin Oasis, located in the northwest of China (Gansu province), which is characterized by several halophytes. Lycium spp. and Peganum nigellastrum were used as trap plants in a greenhouse experiment to identify autochthonous AMF associated with the halophytes’ rhizospheres. Morphological observations showed the typical AMF structures inside roots. Twenty-six molecularly distinct AMF taxa were recovered from soil and root DNA. The taxonomical diversity mirrors the several AMF adapted to extreme environmental conditions, such as the saline soil of central China. Knowledge of the AMF associated with halophytes may contribute to select specific fungal isolates to set up agriculture strategies for protecting non-halophyte crop plants in saline soils

Pyrosequencing analysis of fungal assemblages from geographically distant, disparate soils reveals spatial patterning and a core mycobiome

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 distribution are poorly understood. The degree of fungal community overlap among 16 soil samples from distinct ecosystems and distant geographic localities (truffle grounds, a Mediterranean agro-silvo-pastoral system, serpentine substrates and a contaminated industrial area) was assessed by examining the distribution of fungal ITS1 and ITS2 sequences in a dataset of 454 libraries. ITS1 and ITS2 sequences were assigned to 1,660 and 1,393 Operational Taxonomic Units (OTUs; as defined by 97% sequence similarity), respectively. Fungal beta-diversity was found to be spatially autocorrelated. At the level of individual OTUs, eight ITS1 and seven ITS2 OTUs were found in all soil sample groups. These ubiquitous taxa comprised generalist fungi with oligotrophic and chitinolytic abilities, suggesting that a stable core of fungi across the complex soil fungal assemblages is either endowed with the capacity of sustained development in the nutrient-poor soil conditions or with the ability to exploit organic resources (such as chitin) universally distributed in soils

Arbuscular mycorrhizal symbiosis modulates the apocarotenoid biosynthetic pathway in saffron

[EN] Crocus sativus L. (saffron) has been propagated for millennia to produce the precious spice saffron from the red stigmas. The inebriant organoleptic and bioactive properties mainly depend on the content of crocins (dyeing capacity), picrocrocin (flavor), and safranal (aroma), apocarotenoids deriving from zeaxanthin. In this study, an integrated biochemical and molecular analysis was carried out on fresh saffron stigmas to investigate the in-fluence exerted by the arbuscular mycorrhizal fungus (AMF) Rhizophagus intraradices on the production of the main saffron apocarotenoids responsible for the properties of the spice. Since mineral enrichment due to AM symbiosis has been related to changes in the secondary metabolism of plants, the mineral content of saffron corms at flowering was also analyzed. Rare arbuscules (AMF trade structures) were found in mycorrhized plants. However, the expression of D27, CCD7, and NCED involved in the synthesis of strigolactones (SLs) and abscisic acid (ABA), which promote AM symbiosis, did not change in the stigmas. The transcription of beta-LYC and CCD4a/ b was not affected by AMF, whereas that of CCD2, which encodes the key enzyme producing major apocar-otenoids, was upregulated. The crocin content was reduced in treated plants even if the expression of ALDH, UGT74AD1, and UGT91P3, involved in crocin synthesis, did not change. Conversely, UGT709G1, implicated in picrocrocin synthesis, was overexpressed in the inoculated plants, thus the safranal content was increased in the spice.This research was funded by the program Interreg V-A Francia Italia Alcotra (Grant No. 1139 "ANTEA - Attivita innovative per lo sviluppo della filiera transfrontaliera del fiore edule"; and grant no. 8336 "ANTES-Fiori eduli e piante aromatiche: attivita capitalizzazione dei progetti ANTEA ed ESSICA").Stelluti, S.; Grasso, G.; Nebauer, SG.; Alonso, GL.; Renau-Morata, B.; Caser, M.; Demasi, S.... (2024). Arbuscular mycorrhizal symbiosis modulates the apocarotenoid biosynthetic pathway in saffron. Scientia Horticulturae. 323. https://doi.org/10.1016/j.scienta.2023.11244132

Arbuscular Mycorrhizal Fungi. Methods and Protocols.

Ferrol, N.; Lanfranco, L. (Eds.) 2020 Arbuscular Mycorrhizal Fungi. Methods and Protocols. Vol 2146. pp. 257. ISBN 978 1 0716-0602-