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Here the pangenome analysis of Burkholderia sensu lato (s.l.) was performed for the first time, together with an updated analysis of the pangenome of Burkholderia sensu stricto, and Burkholderia cepacia complex (Bcc) focusing on the Bcc B. catarinensis specific features of its re-sequenced genome. The pangenome of Burkholderia s.l., Burkholderia s.s., and of the Bcc was open, composed of more than 96% of accessory genes, and more than 62% of unknown genes. Functional annotations showed that secondary metabolism genes belonged to the variable portion of genomes, which might explain their production of several compounds with varied bioactivities. Taken together, this work showed the great variability and uniqueness of these genomes and revealed an underexplored unknown potential in poorly characterized genes. Regarding B. catarinensis 89T, its genome harbors genes related to hydrolases production and plant growth promotion. This draft genome will be valuable for further investigation of its biotechnological potentials. • Here the pangenome analysis of Burkholderia sensu lato (s.l.) was performed for the first time. • An updated analysis of the pangenome of Burkholderia sensu stricto (s.s.) and Burkholderia cepacia complex (Bcc) was also performed. • The three pangenomes are open, composed of >96% of accessory genes, >62% of unknown genes and highly variable genomes. • Specific genomic features of the Bcc B. catarinensis 89T related to biotechnological potentials were explored. [ABSTRACT FROM AUTHOR]

[Display omitted] • Alternative Fe-nitrogenase evolutionary aspects in the Panibacillaceae family are investigated. • Diazotrophs represent 17% of Paenibacillaceae genomes sequenced up to now. • Gorillibacterium , Fontibacillus, and Paenibacillus contain Fe-nitrogenase genes. • Fe-nitrogenase was acquired by the ancestral lineage of Fontibacillus and Paenibacillus genera via horizontal gene transfer. • Pangenome of Paenibacillus genus is open and composed of more than 96% of accessory genes. Paenibacillus sonchi genomovar Riograndensis is a nitrogen-fixing bacteria isolated from wheat that displays diverse plant growth-promoting abilities. Beyond conventional Mo-nitrogenase, this organism also harbors an alternative Fe-nitrogenase, whose many aspects related to regulation, physiology, and evolution remain to be elucidated. In this work, the origins of this alternative system were investigated, exploring the distribution and diversification of nitrogenases in the Panibacillaceae family. Our analysis showed that diazotrophs represent 17% of Paenibacillaceae genomes, of these, only 14.4% (2.5% of all Paenibacillaceae genomes) also contained Fe or V- nitrogenases. Diverse nif -like sequences were also described, occurring mainly in genomes that also harbor the alternative systems. The analysis of genomes containing Fe-nitrogenase showed a conserved cluster of nifEN anfHDGK across three genera: Gorillibacterium , Fontibacillus, and Paenibacillus. A phylogeny of anfHDGK separated the Fe-nitrogenases into three main groups. Our analysis suggested that Fe-nitrogenase was acquired by the ancestral lineage of Fontibacillus , Gorillibacterium, and Paenibacillus genera via horizontal gene transfer (HGT), and further events of transfer and gene loss marked the evolution of this alternative nitrogenase in these groups. The species phylogeny of N -fixing Paenibacillaceae separated the diazotrophs into five clades, one of these containing all occurrences of strains harboring alternative nitrogenases in the Paenibacillus genus. The pangenome of this clade is open and composed of more than 96% of accessory genes. Diverse functional categories were enriched in the flexible genome, including functions related to replication and repair. The latter involved diverse genes related to HGT, suggesting that such events may have an important role in the evolution of diazotrophic Paenibacillus. This study provided an insight into the organization, distribution, and evolution of alternative nitrogenase genes in Paenibacillaceae , considering different genomic aspects. [ABSTRACT FROM AUTHOR]