RNASeq libraries of quorum-sensing induced and wild-type M. ciceri bv. biserrulae WSM1271

M. ciceri WSM1271 carries a novel integrative and conjugative element (ICE) termed a tripartite ICE (ICE3) that exists as thee separated DNA regions in the chromosome. Three site-specific recombinases acting on three distinct pairs of attachment sites catalyse recombination between the three ICE3 DNA regions leading to their excision from the chromosome to form a single plasmid-like entity for horizontal conjugative transfer. RNASeq was used to probe for differentially expressed ICE3-encoded genes in WSM1271 wild-type cells, and engineered WSM1271 cells carrying cloned copies of two quorum-sensing loci that induce ICE3 excision and transfer. Overall, 187 significantly differentially expressed genes (adjusted P-value < 0.05) were identified and although ICEMcSym1271 comprised only ~7.6% of the chromosome, 15.5% (29) of the differentially expressed genes were located on ICEMcSym1271. Genes likely involved in activation of excision and conjugation including rdfS, rlxS, msi172-msi171 and the type-IV conjugative pilus gene cluster msi031-trbBCDEJLFGI-msi021 were all significantly induced. The RNA-Seq libraries generated in this study have strongly aided the development of our model detailing the regulation of excision and transfer of ICE3s. rRNA depleted total RNA profiles of WSM1271 wild-type cells or those overexpressing two quorum-sensing loci traI1 (Mesci_2552) and traR1 (Mesci_2553) were generated using Ion Proton sequencing.