Although much is known about the pathology of Bacillus thuringiensis against invertebrates, current understanding of its natural ecology is limited. This study evaluated the biodiversity of B.thuringiensis in relation to its interaction with plants. Phylogenetic relationships between 44 reference and field-collected strains, determined using 16S rRNA and gyrB gene sequences, revealed a high degree of variability, similar to that found in databases. An Arabidopsis thaliana in vitro inoculation model was developed to screen the ability of B.thuringiensis to colonise roots. Significant colonisation differences up to 91-fold were observed between strains, and correlation between strain phylogeny and colonisation was found. The genetics and biochemistry of auxin production; presence of the gene encoding indole pyruvate decarboxylase; and the abilities of Bt strains to swarm, grow in rich/minimal media and affect root growth differed between the strains, but only auxin production correlated significantly with ability to colonise roots. Co-inoculation with Burkholderia phytofirmans PsJN or Pseudomonas fluorescens SBW25 produced no effect on B.thuringiensis colonisation levels, regardless of the co-inoculant. Similarly, root colonisation of A.thaliana mutants impaired in plant defences was not significantly higher compared with controls. This is the first systematic and phylogenetic evaluation of B.thuringiensis interaction with plants.

Three studies explored whether odor can influence people's cognition and behavior without their being consciously aware of the influence. In two studies, we tested and confirmed that when participants were unobtrusively exposed to citrus-scented all-purpose cleaner, the mental accessibility of the behavior concept of cleaning was enhanced, as was indicated by faster identification of cleaning-related words in a lexical decision task and higher frequency of listing cleaning-related activities when describing expected behavior during the day. Finally, a third study established that the mere exposure to the scent of all-purpose cleaner caused participants to keep their direct environment more clean during an eating task. Awareness checks showed that participants were unaware of this influence. The present studies reveal the nonconscious influence that olfactory cues can have on thinking and doing.