title: Identification of genes required by Bacillus thuringiensis for survival in soil by transposon-directed insertion site sequencing.
abstract: Transposon-directed insertion site sequencing was used to identify genes required by Bacillus thuringiensis to survive in non-axenic plant/soil microcosms. A total of 516 genetic loci fulfilled the criteria as conferring survival characteristics. Of these, 127 (24.6 %) were associated with uptake and transport systems; 227 loci (44.0 %) coded for enzymatic properties; 49 (9.5 %) were gene regulation or sensory loci; 40 (7.8 %) were structural proteins found in the cell envelope or had enzymatic activities related to it and 24 (4.7 %) were involved in the production of antibiotics or resistance to them. Eighty-three (16.1 %) encoded hypothetical proteins or those of unknown function. The ability to form spores was a key survival characteristic in the microcosms: bacteria, inoculated in either spore or vegetative form, were able to multiply and colonise the soil, whereas a sporulation-deficient mutant was not. The presence of grass seedlings was critical to colonisation. Bacteria labelled with green fluorescent protein were observed to adhere to plant roots. The sporulation-specific promoter of spo0A, the key regulator of sporulation, was strongly activated in the rhizosphere. In contrast, the vegetative-specific promoters of spo0A and PlcR, a pleiotropic regulator of genes with diverse activities, were only very weakly activated.
authors: Detection Department, Defence Science and Technology Laboratory, Porton Down, Salisbury, Wiltshire, SP4 0JQ, UK, AHBishop@dstl.gov.uk.
authors: Alistair H
authors: AH
authors: Bishop
authors: Phillip A
authors: PA
authors: Rachwal
authors: Alka
authors: A
authors: Vaid
mesh_terms: D000220:Adaptation, Biological / Q000235:genetics*; D001413:Bacillus thuringiensis / Q000737:chemistry / Q000235:genetics*; D004269:DNA, Bacterial / Q000235:genetics; D005798:Genes, Bacterial; D017422:Sequence Analysis, DNA / Q000379:methods; D012988:Soil Microbiology
chemical_list: D004269:DNA, Bacterial