Functional Genomic Analysis of Walnut-nematode Interactions

Plant parasitic nematodes can devastate walnut orchards and may remain dormant deep in the soil profile for several years, beyond reach of traditional pesticides. Nematicides are often very toxic to beneficial organisms and detrimental to the environment; several of the most effective are being phased out. Developing novel methods of diagnosis and control requires characterizing pathogens and their interactions with host and non-host plants through genomic and functional genetic analyses. This project focuses on interactions between walnut roots and Pratylenchus vulnus, an important nematode parasite. The primary goal is to develop a knowledge base of genes involved in interactions between the nematode and the walnut root on which it feeds. Genomics tools such as DNA sequencing and microarrays are being used to create a database available to the walnut research community. The information is then analyzed to identify walnut genes whose expression is changed by nematode infection. This study will establish relationships between nematode infection of walnut roots and expression of specific genes in both organisms and will allow development of diagnostic tests which identify the presence and abundance of specific parasites within the plant’s rhizosphere. In addition, functional genomic techniques are being used to suppress expression of specific nematode genes to identify potential targets for novel pesticides.