RESUMO
Most plants in natural ecosystems associate with arbuscular mycorrhizal (AM) fungi to survive soil nutrient limitations. To engage in symbiosis, AM fungi secrete effector molecules that, similar to pathogenic effectors, reprogram plant cells. Here we show that the Glomeromycotina-specific SP7 effector family impacts on the alternative splicing program of their hosts. SP7-like effectors localize at nuclear condensates and interact with the plant mRNA processing machinery, most prominently with the splicing factor SR45 and the core splicing proteins U1-70K and U2AF35. Ectopic expression of these effectors in the crop plant potato and in Arabidopsis induced developmental changes that paralleled to the alternative splicing modulation of a specific subset of genes. We propose that SP7-like proteins act as negative regulators of SR45 to modulate the fate of specific mRNAs in arbuscule-containing cells. Unraveling the communication mechanisms between symbiotic fungi and their host plants will help to identify targets to improve plant nutrition.
Assuntos
Processamento Alternativo , Arabidopsis , Regulação da Expressão Gênica de Plantas , Micorrizas , Simbiose , Micorrizas/fisiologia , Micorrizas/genética , Simbiose/genética , Arabidopsis/microbiologia , Arabidopsis/genética , Proteínas Fúngicas/metabolismo , Proteínas Fúngicas/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Glomeromycota/fisiologia , Glomeromycota/genética , RNA Mensageiro/metabolismo , RNA Mensageiro/genéticaRESUMO
BACKGROUND: Chronic recurrent multifocal osteomyelitis (CRMO) is a rare autoinflammatory bone disease for which a lack of bacterial involvement is a key diagnostic feature to distinguish it from other symptomatically related diseases. However, the growing evidence suggesting an involvement of the host-associated microbiota in rheumatic disorders together with the now wide accessibility of modern culture-independent methods warrant a closer examination of CRMO. METHODS: In this study, we show through bacterial 16S rRNA gene profiling that numerous features of the oral- and fecal microbial communities differentiate children with and without CRMO. RESULTS: Notably, communities in diseased children are characterized by a lack of potential probiotic bacteria in the fecal community and an overabundance of known pathobionts in the oral microbial communities. Of special interest is the HACEK group, a set of commonly known oral pathogens that are implicated in the development of several acute and chronic diseases such as osteitis and rheumatoid arthritis. Furthermore, we observe that gut bacterial communities in the diseased children appear to reflect an altered host physiology more strongly than the oral community, which could suggest an oral disease origin followed by propagation and/or responses beyond the oral cavity. CONCLUSIONS: Bacterial communities, in particular the oral microbiota, may serve as an indicator of underlying susceptibility to CRMO, or play a yet undefined role in its development.
Assuntos
Microbiota , Osteíte , Osteomielite , Criança , Doença Crônica , Humanos , Microbiota/genética , Osteomielite/diagnóstico , RNA Ribossômico 16S/genéticaRESUMO
Host-induced gene silencing (HIGS) is a methodology that allows the downregulation of genes in organisms living in close association with a host and that are not amenable or recalcitrant to genetic modifications. This method has been particularly used for oomycetes and for filamentous fungi interacting with plants, including the fungi of the arbuscular mycorrhizal symbiosis. Here, we present a protocol developed in our laboratory to downregulate genes from the obligate symbiont Rhizophagus irregularis in symbiosis with Medicago truncatula plants.
