Molecular phylogeny of the Tylenchomorpha establishing an evolutionary framework for the study of plant parasitic nematodes.

U. S. agriculture is economically threatened by nematode plant pathogens including many of the more than 2000 species of Infraorder Tylenchida. This immediate, growing threat is exacerbated by loss of nematicides and increasing global trade/travel, that broadens distribution of exotic nematodes. The result includes regulatory concerns and urgency for novel approaches to nematode management. Most promising of these approaches is exploitation of genomics to target molecular aspects of nematode pathogen biology, leading to more sophisticated engineering of plant resistance via GMO hosts, and to the ability to confound expression of specific nematode parasitism genes. However, these revolutionary approaches require a solid basis for establishing the origin and maintenance of parasitism genes, and definition of their distribution across the enormous genetic diversity of Tylenchida. Apart from an evolutionary framework (phylogeny) the relevant diverse molecular genetic patterns cannot be meaningfully and efficiently explored, compared and extended. Thus, the proposed objective is to develop a robust tylenchid phylogeny and thereby support novel approaches to nematode management. Rapid progress and cost-savings by sharing value-added resources/support (including databases, voucher curation and analytical tools) is ensured through unique linkage to NSF-funded initiatives to develop a deep level phylogeny of Nematoda. Herein, a preliminary analysis of SSU rRNA genes from >130 taxa will guide strategies of taxon and character sampling. Having demonstrated the value for improved phylogenetic resolution of Tylenchida, we will pursue use of the LSU rRNA and several protein coding genes. The study engages broad systematic/molecular expertise with ongoing worldwide contacts and exchange of materials.

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