The floral development of the allotetraploid Coffea arabica L. correlates with a small RNA dynamic reprogramming.

Noncoding and coding RNAs are key regulators of plant growth, development, and stress responses. To investigate the types of transcripts accumulated during the vegetative to reproductive transition and floral development in the Coffea arabica L., we sequenced small RNA libraries from eight developmental stages, up to anthesis. We combined these data with messenger RNA and PARE sequencing of two important development stages that marks the transition of an apparent latent to a rapid growth stage. In addition, we took advantage of multiple in silico tools to characterize genomic loci producing small RNAs such as phasiRNAs, miRNAs, and tRFs. Our differential and co-expression analysis showed that some types of small RNAs such as tRNAs, snoRNAs, snRNAs, and phasiRNAs preferentially accumulate in a stage-specific manner. Members of the miR482/miR2118 superfamily and their 21-nucleotide phasiRNAs originating from resistance genes show a robust co-expression pattern that is maintained across all the evaluated developmental stages. Finally, the majority of miRNAs accumulate in a family stage-specific manner, related to modulated hormonal responses and transcription factor expression.

Phylogenomic characterization and pangenomic insights into the surfactin-producing bacteria Bacillus subtilis strain RI4914.

Bacillus subtilis is a versatile bacterial species able to produce surfactin, a lipopeptide biosurfactant. We carried out the phylogenomic characterization and pangenomic analyses using available B. subtilis complete genomes. Also, we report the whole genome of the biosurfactant-producing B. subtilis strain RI4914 that was isolated from effluent water from an oil exploration field. We applied a hybrid sequencing approach using both long- and short-read sequencing technologies to generate a highly accurate, single-chromosome genome. The pangenomics analysis of 153 complete genomes classified as B. subtilis retrieved from the NCBI shows an open pangenome composed of 28,511 accessory genes, which agrees with the high genetic plasticity of the species. Also, this analysis suggests that surfactin production is a common trait shared by members of this species since the srfA operon is highly conserved among the B. subtilis strains found in most of the assemblies available. Finally, increased surfactin production corroborates the higher srfAA gene expression in B. subtilis strain RI4914.