AUTHOR=Wallner Adrian , Moulin Lionel , Busset Nicolas , Rimbault Isabelle , Béna Gilles 

TITLE=Genetic Diversity of Type 3 Secretion System in Burkholderia s.l. and Links With Plant Host Adaptation

JOURNAL=Frontiers in Microbiology

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2021.761215

DOI=10.3389/fmicb.2021.761215

ISSN=1664-302X

ABSTRACT=<p><italic>Burkholderia sensu lato</italic> species are prominent for their diversity of hosts. The type 3 secretion system (T3SS) is a major mechanism impacting the interactions between bacteria and eukaryotic hosts. Besides the human pathogenic species <italic>Burkholderia pseudomallei</italic> and closely affiliated species, the T3SS has received little attention in this genus as in taxonomically and evolutionary close genera <italic>Paraburkholderia</italic>, <italic>Caballeronia</italic>, <italic>Trinickia</italic>, and <italic>Mycetohabitans</italic>. We proceeded to identify and characterize the diversity of T3SS types using the genomic data from a subset of 145 strains representative of the species diversity found in the <italic>Burkholderia s.l.</italic> group. Through an analysis of their phylogenetic distribution, we identified two new T3SS types with an atypical chromosomal organization and which we propose to name BCI (<italic>Burkholderia</italic> cepacia complex Injectisome) and PSI (<italic>Paraburkholderia</italic> Short Injectisome). BCI is the dominant T3SS type found in <italic>Burkholderia sensu stricto</italic> (<italic>s.s.</italic>) species and PSI is mostly restricted to the <italic>Paraburkholderia</italic> genus. By correlating their distribution with the ecology of their strains of origin, we propose a role in plant interaction for these T3SS types. Experimentally, we demonstrated that a BCI deficient <italic>B. vietnamiensis</italic> LMG10929 mutant was strongly affected in its rice colonization capacity.</p>