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Rescooped by Zahra Feghhi from Mycorrhizal fungal genomes
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The transcriptome of the arbuscular mycorrhizal fungus Glomus intraradices (DAOM 197198) reveals functional tradeoffs in an obligate symbiont

The transcriptome of the arbuscular mycorrhizal fungus Glomus intraradices (DAOM 197198) reveals functional tradeoffs in an obligate symbiont | Best Earth | Scoop.it

The arbuscular mycorrhizal symbiosis is arguably the most ecologically important eukaryotic symbiosis, yet it is poorly understood at the molecular level. To provide novel insights into the molecular basis of symbiosis-associated traits, we report the first genome-wide analysis of the transcriptome from Glomus intraradices DAOM 197198.
We generated a set of 25 906 nonredundant virtual transcripts (NRVTs) transcribed in germinated spores, extraradical mycelium and symbiotic roots using Sanger and 454 sequencing. NRVTs were used to construct an oligoarray for investigating gene expression.
We identified transcripts coding for the meiotic recombination machinery, as well as meiosis-specific proteins, suggesting that the lack of a known sexual cycle in G. intraradices is not a result of major deletions of genes essential for sexual reproduction and meiosis. Induced expression of genes encoding membrane transporters and small secreted proteins in intraradical mycelium, together with the lack of expression of hydrolytic enzymes acting on plant cell wall polysaccharides, are all features of G. intraradices that are shared with ectomycorrhizal symbionts and obligate biotrophic pathogens.
Our results illuminate the genetic basis of symbiosis-related traits of the most ancient lineage of plant biotrophs, advancing future research on these agriculturally and ecologically important symbionts.

 

Tisserant et al.

New Phytologist
Volume 193, Issue 3, pages 755–769, February 2012

http://dx.doi.org/10.1111/j.1469-8137.2011.03948.x


Via Stefano Ghignone
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Rescooped by Zahra Feghhi from Mycorrhizal fungal genomes
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A Secreted Fungal Effector of Glomus intraradices Promotes Symbiotic Biotrophy

A Secreted Fungal Effector of Glomus intraradices Promotes Symbiotic Biotrophy | Best Earth | Scoop.it

Biotrophic fungi interacting with plants establish long-term relationships with their hosts to fulfill their life cycles. In contrast to necrotrophs, they need to contend with the defense mechanisms of the plant to develop within the host and feed on living cells. It is generally accepted that microbial pathogens produce and deliver a myriad of effector proteins to hijack the cellular program of their hosts. Arbuscular mycorrhizal (AM) fungi are the most widespread biotrophs of plant roots. We investigated whether AM fungi use effector proteins to short-circuit the plant defense program. Here we show that Glomus intraradices secretes a protein, SP7, that interacts with the pathogenesis-related transcription factor ERF19 in the plant nucleus. ERF19 is highly induced in roots by the fungal pathogen Colletotrichum trifolii as well as by several fungal extracts, but only transiently during mycorrhiza colonization. When constitutively expressed in roots, SP7 leads to higher mycorrhization while reducing the levels of C. trifolii-mediated defense responses. Furthermore, expression of SP7 in the rice blast fungus Magnaporthe oryzae attenuates root decay symptoms. Taken together, these results suggest that SP7 is an effector that contributes to develop the biotrophic status of AM fungi in roots by counteracting the plant immune program.

 

Silke Kloppholz, Hannah Kuhn, Natalia Requena

Current Biology

Volume 21, Issue 14, 26 July 2011, Pages 1204–1209

http://dx.doi.org/10.1016/j.cub.2011.06.044


Via Stefano Ghignone
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