https://www.ruhr-uni-bochum.de/imperia/md/content/geobot/2007/hibbett_2007-a_higher-level-phylogenetic.pdf

A higher-level phylogenetic classification of the Fungi

Arbuscular mycorrhizal (AM) fungi form mutualistic, symbiotic associations with the roots of more than 80% of land plants. The fungi are incapable of completing their life cycle in the absence of a host root. Their spores can germinate and grow in the absence of a host, but their hyphal growth is very limited. Little is known about the molecular mechanisms that govern signalling and recognition between AM fungi and their host plants. In one of the first stages of host recognition, the hyphae of AM fungi show extensive branching in the vicinity of host roots before formation of the appressorium, the structure used to penetrate the plant root. Host roots are known to release signalling molecules that trigger hyphal branching, but these branching factors have not been isolated. Here we have isolated a branching factor from the root exudates of Lotus japonicus and used spectroscopic analysis and chemical synthesis to identify it as a strigolactone, 5-deoxy-strigol. Strigolactones are a group of sesquiterpene lactones, previously isolated as seed-germination stimulants for the parasitic weeds Striga and Orobanche. The natural strigolactones 5-deoxy-strigol, sorgolactone and strigol, and a synthetic analogue, GR24, induced extensive hyphal branching in germinating spores of the AM fungus Gigaspora margarita at very low concentrations.

Plant sesquiterpenes induce hyphal branching in arbuscular mycorrhizal fungi

Jasmonates: biosynthesis, perception, signal transduction and action in plant stress response, growth and development. An update to the 2007 review in Annals of Botany

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/6A4E3EB5D8D502B5571F591F5B705C47/S0953756201005196a.pdf/div-class-title-a-new-fungal-phylum-the-span-class-italic-glomeromycota-span-phylogeny-and-evolution-div.pdf

A new fungal phylum, the Glomeromycota: phylogeny and evolution

Arbuscular mycorrhiza (AM), a symbiosis between plants and members of an ancient phylum of fungi, the Glomeromycota, improves the supply of water and nutrients, such as phosphate and nitrogen, to the host plant. In return, up to 20% of plant-fixed carbon is transferred to the fungus. Nutrient transport occurs through symbiotic structures inside plant root cells known as arbuscules. AM development is accompanied by an exchange of signalling molecules between the symbionts. A novel class of plant hormones known as strigolactones are exuded by the plant roots. On the one hand, strigolactones stimulate fungal metabolism and branching. On the other hand, they also trigger seed germination of parasitic plants. Fungi release signalling molecules, in the form of 'Myc factors' that trigger symbiotic root responses. Plant genes required for AM development have been characterized. During evolution, the genetic programme for AM has been recruited for other plant root symbioses: functional adaptation of a plant receptor kinase that is essential for AM symbiosis paved the way for nitrogen-fixing bacteria to form intracellular symbioses with plant cells.

Arbuscular mycorrhiza: the mother of plant root endosymbioses.

Glomus, the Largest Genus of the Arbuscular Mycorrhizal Fungi (Glomales), Is Nonmonophyletic

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/045310040DC29A271C5E72E292BD075E/S0953756200003725a.pdf/div-class-title-analysis-of-partial-span-class-italic-glomales-span-ssu-rrna-gene-sequences-implications-for-primer-design-and-phylogeny-div.pdf

Analysis of partial Glomales SSU rRNA gene sequences: implications for primer design and phylogeny

We describe a method that allows quick and easy PCR amplification and cloning of nearly complete SSU rRNA genes from arbuscular mycorrhizal fungi. The procedure tested on spores from 37 different glomalean isolates was based on magnetic separation with Dynabeads, followed by nested PCR with two primer pairs. All trials led to visible amplification products of the expected size. Thereafter, the PCR fragments could be quickly and efficiently cloned by means of a topoisomerase-activated vector (pCR2.1-TOPO). The technique is rapid, uncomplicated and comparatively inexpensive. The use of single spores for DNA extraction has some advantages over multispore-preparations, e.g. it is less susceptible to contamination with other organisms present in the cultures. The method can be used for the quick and reliable preparation of a large number of samples and is highly reproducible. It could also be used for genes other than the SSU rRNA gene.

Daniel Schwarzott

Papers

A new fungal phylum, the Glomeromycota: phylogeny and evolution

Glomus, the Largest Genus of the Arbuscular Mycorrhizal Fungi (Glomales), Is Nonmonophyletic

Analysis of partial Glomales SSU rRNA gene sequences: implications for primer design and phylogeny

A simple and reliable method for SSU rRNA gene DNA extraction, amplification, and cloning from single AM fungal spores

Molecular phylogeny of the genus Kalanchoe (Crassulaceae) inferred from nucleotide sequences of the ITS-1 and ITS-2 regions.