Interaction between plant growth promoting rhizobacteria and foliar feeding insects

Plant Growth Promoting Rhizobacteria (PGPR) are a prime component of the soil microbial community and recent research shows that they can enhance the chemical defences of plants. Foliar secondary metabolites of plants have been widely studied for their role in defence functions against invading herbivores. However, the role of PGPR in determining the qualitative and quantitative aspects of secondary metabolites and thus the effects of rhizobacteria-plant-herbivore tritrophic interactions remains sparsely explored. Therefore, it is critical to understand how and why PGPR affect foliar-feeding insects, in a microbial and chemical ecology framework. The aim of this study is to determine the potential of plant growth promoting Bacillus in alteration of plant secondary metabolite profile and consequently in the development of plant resistance against generalist and specialist foliar feeding insects. Experiments have been undertaken in which the effects of different soil microbial enhancement methods are tested on vegetable crops, the alterations in foliar leaf chemistry presented and consequences for above ground insects determined.