Project description:To identify the mechanism of how the microbiota induces lateral root development independently of auxin signalling, we performed a transcriptional analysis using roots of wild type plants and lateral root mutants arf7 arf19, nph4-1, lbd16-1, and gnom184, in mono-association with a selection of 16 bacteria able to restore the lateral root formation in the mutants used.
Project description:Background: The soil environment is responsible for sustaining most terrestrial plant life on earth, yet we know surprisingly little about the important functions carried out by diverse microbial communities in soil. Soil microbes that inhabit the channels of decaying root systems, the detritusphere, are likely to be essential for plant growth and health, as these channels are the preferred locations of new root growth. Understanding the microbial metagenome of the detritusphere and how it responds to agricultural management such as crop rotations and soil tillage will be vital for improving global food production. Methods: The rhizosphere soils of wheat and chickpea growing under + and - decaying root were collected for metagenomics sequencing. A gene catalogue was established by de novo assembling metagenomic sequencing. Genes abundance was compared between bulk soil and rhizosphere soils under different treatments. Conclusions: The study describes the diversity and functional capacity of a high-quality soil microbial metagenome. The results demonstrate the contribution of the microbiome from decaying root in determining the metagenome of developing root systems, which is fundamental to plant growth, since roots preferentially inhabit previous root channels. Modifications in root microbial function through soil management, can ultimately govern plant health, productivity and food security.
Project description:The identification of processes activated by specific microbes during microbiota colonization of plant roots has been hampered by technical constraints in metatranscriptomics. These include lack of reference genomes, high representation of host or microbial rRNA sequences in datasets, or difficulty to experimentally validate gene functions. Here, we recolonized germ-free Arabidopsis thaliana with a synthetic, yet representative root microbiota comprising 106 genome-sequenced bacterial and fungal isolates. We used multi-kingdom rRNA depletion, deep RNA-sequencing and read mapping against reference microbial genomes to analyse the in-planta metatranscriptome of abundant colonizers. We identified over 3,000 microbial genes that were differentially regulated at the soil-root interface. Translation and energy production processes were consistently activated in planta, and their induction correlated with bacterial strains’ abundance in roots. Finally, we used targeted mutagenesis to show that several genes consistently induced by multiple bacteria are required for root colonization in one of the abundant bacterial strains (a genetically tractable Rhodanobacter). Our results indicate that microbiota members activate strain-specific processes but also common gene sets to colonize plant roots.
Project description:Suppression of chronic Arabidopsis immune responses is a widespread but typically strain-specific trait across the major bacterial lineages of the plant microbiota. Here, through phylogenetic analysis of 1,765 Xanthomonadales genomes, we show that immunomodulation is a highly conserved, ancestral trait across this core order of the plant microbiota, and preceded specialization of these bacteria as host-adapted pathogens. Rhodanobacter R179, from the deepest branch of the Xanthomonadales, activates immune responses which are dependent on EFR and SOBIR1 cell-surface receptor complexes, yet root transcriptomics suggest the commensal evades host recognition upon prolonged association. This commensal camouflage is likely due to the combined activities of the conserved ABC transporter permease (dssA) and the TonB-dependent transporter (dssB) and the selective elimination of immunogenic elicitors produced by R179, other microbiota members, and the plant host. The ability of R179 to mask itself and other commensals from host recognition is consistent with a convergence of distinct root transcriptomes triggered by immunosuppressive or non-suppressive synthetic communities upon R179 co-inoculation. Although root load of R179 on wild-type and efr fls2 sobir1 mutant plants was indistinguishable in mono-associations, immunomodulation through dssAB provided R179 with a competitive advantage in a community context in the absence of other immunosuppressive bacteria. Furthermore, root colonization of diverse commensal Xanthomonadales strains varied 1,000-fold without detrimental impacts on the host. We propose that conservation of immunomodulation by Xanthomonadales is related to their adaptation to terrestrial habitats and might have contributed to variation in strain-specific root association, which together accounts for their prominent role in plant microbiota establishment.
Project description:External auditory canal squamous cell carcinoma (EACC) is very rare, only accounting for two thousandth of the head and neck cancer. However, the development mechanism of EACC remains unknown. By using gene expression microarray analysis, we aimed to find differentially expressed genes involved in ESCC development. We identified a wide spectrum of molecular signatures in EACC, including mRNA and lncRNA. The present study systematically analyzed the expression of mRNA and lncRNA in squamous cell carcinoma of the external auditory canal and normal external auditory canal tissues. We detect the transcriptomic changes between squamous cell carcinoma of the external auditory canal and normal external auditory canal tissues to identify potential tumor biomarkers in squamous cell carcinoma of the external auditory canal.
Project description:Etiologically linked to HPV infection, malignancies of the anal canal have substantially increased in incidence over the last 20 years. Although most anal squamous cell carcinomas (SCC) respond well to chemoradiotherapy, for undetermined reasons, a subgroup of patients experience a poor outcome. Despite cumulative efforts for discovering independent predictors for overall survival, both nodal status and tumor size are still the only reliable factors predicting patient outcome. In the present study, we correlated both proteomic signatures and clinicopathological features of neoplastic lesions arising from two distinct portions of the anal canal: the lower part (squamous zone) and the more proximal anal transitional zone. Although microdissected cancer cells appeared indistinguishable by morphology (squamous phenotype), unsupervised clustering analysis of the whole proteome significantly highlighted the heterogeneity that exists within anal canal tumors. More importantly, two region-specific subtypes of SCC were revealed. The expression profile (sensitivity/specificity) of several selected biomarkers (keratin filaments) further confirmed the subclassification of anal (pre)cancers based on their cellular origin. Less commonly detected compared to their counterparts located in the squamous mucosa, SCC originating in the transitional zone displayed more frequently a poor or basaloid differentiation and were significantly correlated with reduced disease-free and overall survivals. Taken together, we present for the first time direct evidence that anal canal SCC comprises two distinct entities with different cells of origin, proteomic signatures and survival rates. This study forms the basis for a novel dualistic classification of anal carcinoma with implications for management, outcome expectations and possibly therapeutic approaches.