Whole genome sequencing revealed host adaptation-focused genomic plasticity of pathogenic Leptospira

Abstract

Leptospirosis, caused by pathogenic Leptospira spp., has recently been recognized as an emerging infectious disease worldwide. Despite its severity and global importance, knowledge about the molecular pathogenesis and virulence evolution of Leptospira spp. remains limited. Here we sequenced and analyzed 102 isolates representing global sources. A high genomic variability were observed among different Leptospira species, which was attributed to massive gene gain and loss events allowing for adaptation to specific niche conditions and changing host environments. Horizontal gene transfer and gene duplication allowed the stepwise acquisition of virulence factors in pathogenic Leptospira evolved from a recent common ancestor. More importantly, the abundant expansion of specific virulence-related protein families, such as metalloproteases-associated paralogs, were exclusively identified in pathogenic species, reflecting the importance of these protein families in the pathogenesis of leptospirosis. Our observations also indicated that positive selection played a crucial role on this bacteria adaptation to hosts. These novel findings may lead to greater understanding of the global diversity and virulence evolution of Leptospira spp.

Complete Genome Sequence of Leptospira alstonii Serovar Room22 Strain GWTS #1

“…Pathogenic leptospires are divided into 10 species, which include Leptospira alstonii , formerly known as Leptospira genomospecies 1 (2, 3). Two serovars of L. alstonii have been described, serovar Pingchang and serovar Sihuan, both of which were isolated from frogs in China (4). Additionally, four isolates of L. alstonii were cultured from soils in Japan and one isolate from an environmental sample in Malaysia (5, 6).…”

Pathogenic <i>Leptospira</i>: Advances in understanding the molecular pathogenesis and virulence

“…Put together, this information further improves our understanding the genes and the pathways that modulate the pathogenesis of Leptospira species. Leptospira Genome Numerous studies have described the genome of Leptospira species (Alt et al, 2015;Martins-Pinheiro et al, 2016;Xu et al, 2016). Previous analysis classified approximately 45% (n=10) of the known (n=22) Leptospira species (Bourhy et al, 2014), with over 300 whole genomes of Leptospira sequences published, most being those from L. interrogans (Nascimento et al, 2004;Alt et al, 2015).…”

“…Previous analysis classified approximately 45% (n=10) of the known (n=22) Leptospira species (Bourhy et al, 2014), with over 300 whole genomes of Leptospira sequences published, most being those from L. interrogans (Nascimento et al, 2004;Alt et al, 2015). Recent sequence analysis of 102 isolates representing global sources revealed a high genomic variability among different Leptospira species, attributable to systems of adaptation to specific habitats and changes in the host environmental conditions (Xu et al, 2016 et al, 2015), with 14 significantly enriched categories, 50% of the which were immunoreactive antigens (Lessa-Aquino et al, 2015). Various previous studies have documented the L. interrogans transcript (Lo et al, 2010;Pinne et al, 2012;Iraola et al, 2016).…”

“…Additional horizontal gene transfer http: //www.openveterinaryjournal.com C. Ghazaei Open Veterinary Journal, (2018), Vol. 8(1): 13-24 ________________________________________________________________________________________________________ 15 and gene duplication studies conducted recently attempted to describe the process through which pathogenic Leptospira acquire virulence factors (Xu et al, 2016). These studies also described the virulencerelated protein families that showed virulence characteristics, and paralogs associated with metalloproteases-found only in pathogenic Leptospira (Xu et al, 2016).…”

“…8(1): 13-24 ________________________________________________________________________________________________________ 15 and gene duplication studies conducted recently attempted to describe the process through which pathogenic Leptospira acquire virulence factors (Xu et al, 2016). These studies also described the virulencerelated protein families that showed virulence characteristics, and paralogs associated with metalloproteases-found only in pathogenic Leptospira (Xu et al, 2016). Putting together, these results show that there are genetic determinants in infectious species and clades of Leptospira that mediate mechanisms through which pathogenesis occurs and that these unique genes and gene variants are not found in noninfectious Leptospira species.…”