Project description:A transcriptome of Cluster II Frankia in nitrogen-fixing root-nodule symbiosis with the host plant, Datisca glomerata, was obtained by Illumina sequencing and mapping to the corresponding published genome (NCBI Bioproject PRJNA46257). Major metabolic pathways detected in Cluster II Frankia in symbiosis with Datisca glomerata were comparable to those described as up-regulated in the Frankia alni-Alnus glutinosa symbiosis (N Alloisio et al, MPMI 23(5):593-607, 2010): nitrogenase biosynthesis, tricarboxylic acid cycle, respiratory-chain related functions, oxidation protection, and terpenoid biosynthesis. These functions are consistent with the primary activities of Frankia in root nodules, e.g. to carry out the energetically-demanding fixation of atmospheric dinitrogen to ammonium, and to maintain internal reducing conditions. Expression of genes coding for amino-acid biosynthetic pathways, including arginine as reported previously (AM Berry et al. Funct Plant Biol 38, 645–652, 2011) was detected. A striking difference from other Frankia strains, revealed in the transcriptome of the Cluster II Frankia in symbiosis, was the expression of homologs of rhizobial nodulation genes, nodA, nodB and nodC.
Project description:Nucleolar ribosomal DNA (rDNA) repeats control ribosome manufacturing. rDNA harbors a ribosomal RNA (rRNA) gene and an intergenic spacer (IGS). RNA polymerase (Pol) I transcribes rRNA genes yielding the rRNA components of ribosomes. Pol II at the IGS induces rRNA production by preventing Pol I from excessively synthesizing IGS non-coding RNAs (ncRNAs) that can disrupt nucleoli. At the IGS, Pol II regulatory processes and whether Pol I function can be beneficial remain unknown. Here, we identify IGS Pol II regulators, uncovering nucleolar optimization via IGS Pol I. Compartment-enriched proximity-dependent biotin identification (compBioID) showed enrichment of the TATA-less promoter-binding TBPL1 and transcription regulator PAF1 with IGS Pol II. TBPL1 localizes to TCT motifs, driving Pol II and Pol I and maintaining its baseline ncRNA levels. PAF1 promotes Pol II elongation, preventing unscheduled R-loops that hyper-restrain IGS Pol I and its ncRNAs. PAF1 or TBPL1 deficiency disrupts nucleolar organization and rRNA biogenesis. In PAF1-deficient cells, repressing unscheduled IGS R-loops rescues nucleolar organization and rRNA production. Depleting IGS Pol I-dependent ncRNAs is sufficient to compromise nucleoli. We present the interactome of nucleolar Pol II and show its control by TBPL1 and PAF1 ensures IGS Pol I ncRNAs maintaining nucleolar structure and operation.
Project description:Purpose: To compare RNASeq data of Frankia inefficax EuI1c in normal growth conditions to biphenyl-stressed Frankia inefficax EuI1c. Frankia cultures were grown for 3 days under one of three conditions before harvesting: 1.) 1 mM biphenyl stress with glucose as an alternative carbon and energy source, 2.) 1mM biphenyl with no alternative carbon or energy source, or 3.) media with glucose as a carbon and energy source (Control). RNA-seq analysis provided insight into how the the bacteria responds to biphenyl stress and exhibits biphenyl tolerance.
Project description:Purpose: To compare RNASeq data of Frankia strains (EAN1pec, EuIC and EUN1f) under nitrogen stress. Frankia cultures were grown for 2 days under nitrogen replete (+NH4) or nitrogen- deficient (N2) conditions. RNA-seq analysis provided insight into how the the bacteria responds to nitrogen stress.
Project description:Purpose: To compare RNASeq data of Frankia CcI3 in plants under salt stress. Casuarina glauca root nodules infected with Frankia CcI3 were exposed to either no salt or 100 mM NaCl for 21 days. RNA-seq analysis provided insight into how the sybiont responds to salt stress.