Open AccessNecrotrophism Is a Quorum-Sensing-Regulated Lifestyle in Bacillus thuringiensis
Author(s) -
Thomas Dubois,
Karoline Fægri,
Stéphane Perchat,
Christelle Lemy,
Christophe Buisson,
Christiielsen-LeRoux,
Michel Gohar,
Philippe Jacques,
Nalini Ramarao,
AnneBrit Kolstø,
Didier Lereclus
Publication year - 2012
Publication title -
plos pathogens
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.719
H-Index - 206
eISSN - 1553-7374
pISSN - 1553-7366
DOI - 10.1371/journal.ppat.1002629
Subject(s) - quorum sensing , bacillus thuringiensis , biology , biofilm , microbiology and biotechnology , transcriptome , multicellular organism , bacteria , host (biology) , mutant , gene , swarming motility , swarming (honey bee) , genetics , gene expression
How pathogenic bacteria infect and kill their host is currently widely investigated. In comparison, the fate of pathogens after the death of their host receives less attention. We studied Bacillus thuringiensis ( Bt ) infection of an insect host, and show that NprR, a quorum sensor, is active after death of the insect and allows Bt to survive in the cadavers as vegetative cells. Transcriptomic analysis revealed that NprR regulates at least 41 genes, including many encoding degradative enzymes or proteins involved in the synthesis of a nonribosomal peptide named kurstakin. These degradative enzymes are essential in vitro to degrade several substrates and are specifically expressed after host death suggesting that Bt has an active necrotrophic lifestyle in the cadaver. We show that kurstakin is essential for Bt survival during necrotrophic development. It is required for swarming mobility and biofilm formation, presumably through a pore forming activity. A nprR deficient mutant does not develop necrotrophically and does not sporulate efficiently in the cadaver. We report that necrotrophism is a highly regulated mechanism essential for the Bt infectious cycle, contributing to spore spreading.