The diversity, biology and dynamics of microbial agents that regulate nematode populations in the rhizosphere

Abstracts are not currently available in GtR for all funded research. This is normally because the abstract was not required at the time of proposal submission, but may be because it included sensitive information such as personal details.

Nematode populations may be regulated in natural and disturbed ecosystems by microbial natural enemies. In some intensive production systems e.g. cereal monoculture, natural microbial enemies have increased to levels that control specific nematode pests. These 'suppressive' soils are slow to develop and difficult to exploit but provide a valuable resource for studying nematode interactions with the rhizosphere microbial community and for isolation of potential biological control agents. This project studies the population dynamics of cyst and root-knot nematode pests and their natural enemies, the bacterium Pasteuria penetrans and the fungus, Pochonia chlamydosporia.
The two major targets are:
a) to understand the interactions of P. chlamydosporia with its hosts, plants and other organisms in the rhizosphere at the molecular, whole organism and population level in order to develop rational biological control strategies based on this fungal agent
b) to study the genomics of P. penetrans in order to discover genes that may provide novel approaches to nematode management.
Key issues addressed, which relate to the success of P. chlamydosporia as a biological control agent are the role of intra-specific variation in the regulation of nematode host populations and the importance of nutrition in the transition of the fungus from a saprotroph in the rhizosphere to a parasite of nematode eggs. There is no simple relationship between the abundance of the fungus in soil and its efficacy as a biological control agent.
Research on the genomics of P. penetrans is underpinned by a collaboration between Rothamsted and North Carolina State University, which aims to sequence the genome of the bacterium and be the first microbial natural enemy of a nematode to have full sequence information. Such data is used to study the interactions between the bacterium and its hosts, especially genes that relate to the infective spore attachment process and bacterial metabolism.

unavailable