Progress 10/01/00 to 10/01/05
Outputs
This project was discontinued at the University of Florida with the relocation of BJ Adams to Utah in 2003. Some work has continued in Utah.
Impacts
Greater knowledgge of the genetic basis of parasitism can lead to improved technologies for pest control.
Publications
- No publications reported this period
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Progress 10/01/02 to 10/01/03
Outputs
In the last year progress was made in the following areas: 1. Numerous species of plant parasitic Tylenchid nematodes were collected, identified, sequenced, and added to the growing multiple sequence alignment for phylogenetic analysis. Preliminary alignments were optimized and phylogenetic trees explored. Meloidogyninae (root-knot nematodes) and Heteroderidae (cyst nematodes), two of the most damaging groups of plant parasites previously thought to be closely related are shown to not be sister taxa. Instead, the Meloidogyninae are most closely related to the Hemicycliophoridae. This finding will significantly impact genome projects that aim to extend and identify genetic controls of parasitism in root-knot and cyst nematodes because they are much more distantly related than heretofore imagined. 2. Species boundaries for populations of Xiphinema (lance nematode) and Belonolaimus (sting nematode) have been explored in detail. New taxa have been identified that are
correlated with expansions of host range and other bionomic factors. Species previously thought to be benign have been indicted in host range expansion. We show that these populations actually represent new, undescribed species that have probably invaded from non-agricultural hosts. 3. Several new taxa of insect parasitic nematodes have been identified and are currently being described as new species and assayed for their ability to control pest insects, particularly mole crickets and the citrus root weevil. 4. The genetic structure of numerous (over 70) strains of endosymbiotic bacteria of insect pathogenic nematodes have been identified and characterized and are currently being used to inform genome exploration and microarray projects. 5. The origin and maintenance of nematode parasitism, and surveys of geographic distribution and host ranges of mollusks has been studied as a prelude to using nematodes as control agents of pest gastropods.
Impacts
1. Our work on the phylogenetics of plant parasitic nematodes shows that the assumption of evolutionary similarity among major plant parasitic nematodes is bogus and could lead to a significant amount of ineffective research effort.. (= saving billions of dollars worldwide and alleviating much human suffering due to malnutrition) 2. Now that we know that tnewly discovered damage to citrus and strawberry is due to highly structured and genetically divergent evolutionary lineages (different species, not just variation among populations), growers now have the information they need to make more informed choices about the measures needed to take for improved crop protection. (= saving millions of dollars statewide in citrus and strawberries) 3. Use of indigenous nematodes to control pest insects are more effective, and offer longer lasting protection, than the non-native entomopathogenic nematodes. (= millions of dollars saved due to decreased cost of pest control;
decreased impact on native habitats). 4. Because we have shown that some bacteria associated with entomopathogenic nematodes do not always show high levels of host fidelity, workers in biological control will need to contend with the fact that nematodes can pick up non-native endosymbionts and move them to unintentional (or intentional) targets. (= significant tool for further genetic dissections, improved pest management)
Publications
- Zhang, Y., I. Calin-Jageman, J. R. Gurnon, B. J. Adams, A. W. Nicholson, and J. L. Van Etten. 2003. Characterization of a chlorella virus PBCV-1 encoded ribonuclease III. Virology in press.
- Grewal, P. S., S. K. Grewal, L. Tan and B. J. Adams. 2003. Parasitism of Mollusks by Nematodes: Types of Associations and Evolutionary Trends. Journal of Nematology 35(2):146-156.
- Nadler, SA, R. A. Carreno, B. J. Adams. H. Kinde, J. G. Baldwin, and M. Mundo-Ocampo. 2003. Molecular phylogenetics and diagnosis of soil and clinical isolates of Halicephalobus gingivalis (Nematoda: Cephalobina: Panagrolaimoidea), an opportunistic pathogen of horses. 2003. International Journal for Parasitology 33: 1115-1125.
- Nguyen, K. B. and B. J. Adams. 2003. SEM and systematic studies of Steinernema abbasi Elawad et al., 1997, and S. riobrave Cabanillas et al., 1994 (Rhabditida: Steinernematidae). Zootaxa 179: 1-10.
- Tartar, A., D. G. Boucias, J. J. Becnel and B. J. Adams. 2003. Comparison of plastid 16S rDNA (rrn16) genes from Helicosporidium spp.: evidence supporting the reclassification of Helicosporidia as green algae (Chlorophyta). International Journal of Systematic and Evolutionary Microbiology. In Press
- Dickman, M. B., Y.-S. Ha, Z. Yang, B. Adams, and C. Huang. 2003. A protein kinase from Colletotrichum trifolii is induced by plant cutin and is required for appressorium formation. Molecular Plant-Microbe Interactions 16(3):411-421.
- Shapiro-Ilan, D. I., W. A. Gardner, J. R. Fuxa, B W. Wood, K. B. Nguyen, B. J. Adams., R. A. Humber, and M. J. Hall. 2003. Survey of entomopathogenic nematodes and fungi endemic to pecan orchards of the Southeastern US and their virulence to the pecan weevil (Coleoptera: Curculionidae). Environmental Entomology 32(1):187-195.
- Rodrigues, J.C.V., C.C. Childers, M. Gallo-Meagher, R. Ochoa and B. J. Adams. 2003. Mitochondrial DNA and RAPD polymorphisms in the haploid mite Brevipalpus phoenicis (Acari: Tenuipalpidae). Experimental and Applied Acarology (submitted).
- Nguyen, K. B., D. I. Shapiro-Ilan, R. J. Stuart, C. W. McCoy, R. R. James and B. J. Adams. 2003. Heterorhabditis mexicana n. sp. (Heterorhabditidae: Rhabditida) from Tamaulipas, Mexico. Nematology (submitted).
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Progress 10/01/01 to 10/01/02
Outputs
Numerous isolates of entomopathogenic nematodes from the southeastern United States, Mexico, and Asia have been investigated taxonomically, and several strains have been identified as candidates for novel biological control applications. Surveys for entomopathogenic nematodes from these locations have led to new distribution records for several species, and the discovery of new species. Phylogenetic analysis of the Tylenchida, with emphasis on the position of insect parasitic groups among the plant parasitic groups is underway. We have successfully PCR amplified chitinase genes from plant and insect parasitic Tylenchids, and are expanding our taxonomic sampling of these groups. We have completed taxonomic and systematic treatments of the Heterorhabditidae and Steinernematidae (two families of entomopathogenic nematodes), and investigated coevolutionary relationships among ectoparasitic nematodes for moths (Acugutturidae). We are establishing a more robust framework
for comparing the origin and maintenance of `parasitism genes' by expanding the number of taxa and molecular markers.
Impacts
Our survey and taxonomic work complements commercial implementation of entomopathogenic nematodes into agronomic systems, particularly for the control of citrus root weevil and mole crickets in Florida and the Caribbean basin. As components of larger integrated pest management programs, these entomopathogenic nematodes have already had a significant impact in controlling insect pests in these areas, particularly for citrus production and cattle forage. Our work on the diversity and evolution of `parasitism genes' among plant and insect parasitic nematodes suggests that they are evolutionarily plastic, yet taxonomically widespread, reinforcing them as targets for pharmico-chemical or genetic manipulation. In the near future, the ability to control or manipulate the expression and function of these gene products can be harnessed to manage plant damage by insects and plant pathogenic nematodes.
Publications
- Shapiro-Ilan, D. I., W. A. Gardner, J. R. Fuxa, B W. Wood, K. B. Nguyen, B. J. Adams., R. A. Humber, and M. J. Hall. Survey of entomopathogenic nematodes and fungi endemic to pecan orchards of the Southeastern US and their virulence to the pecan weevil (Coleoptera: Curculionidae). 2002. Biological Control. In Press
- Marti, O. G., Adams, B. J. and Sylvain, J-F . 2002. Speciation in the Acugutturidae. Nematology. 4(4):489-504.
- Adams, B. J. and K. B. Nguyen. 2002. Taxonomy and Systematics. Pp. 1-34 In Entomopathogenic Nematology, R. Gaugler, (ed.). CAB publishing, CAB International.
- Adams, B. J. 2002. Bioassays of entomopathogenic microbes and nematodes. Annals of the Entomological Society of America 95:139-140.
- Nguyen, K. B., J. Maruniak and B. J. Adams. 2001. The diagnostic and phylogenetic utility of the rDNA internal transcribed spacer sequences of Steinernema. Journal of Nematology 33:73-82.
- Adams, B. J. 2001. Species concepts and entomopathogenic nematodes: What species are, how we can find them, and an application to the genus Heterorhabditis. Pp 30 - 35 In: C. T. Griffin, A. M. Burnell, M. J. Downes and R. Mulder (Eds.). Developments in entomopathogenic nematode/bacterial research. European Commission Publications, Luxembourg.
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