Location: Molecular Plant Pathology Laboratory
Project Number: 8042-21000-271-13-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Sep 15, 2014
End Date: Sep 14, 2019
Objective 1: Determine the specific genes of Pratylenchus penetrans, Glycine max and alfalfa (Medicago sativa) involved in the parasitism of root-lesion nematode (RLN). Elucidate key genes and processes involved in host resistance and RLN pathogenicity. Select essential metabolic and parasitism genes of RLN that could be targeted for nematode control. Objective 2: Characterize two biotechnological strategies against RLN for resistance in lilies. 1) Study the potential of inducing an effective host resistance against RLN through RNA-mediated interference technology (RNAi); 2) Study the potential of dietary overexpressing proteins, such as cysteine proteinase inhibitors (cystatins) and Bacillus thuringiensis crystal proteins, in planta. Objective 3: (additional objective): Characterize genomes of disease-causing phytoplasmas potentially threatening alfalfa and identify alfalfa genes involved in stress responses and resistance to plant pathogens. Objective 4: (additional objective): Utilize transient expression, molecular transformation and functional analysis to identify key parasitism genes of burrowing nematodes Radopholus similis and host genes involved in resistance to the nematode. Burrowing nematodes are in the same family as the root lesion nematode and often found together with it.
Large-scale transcriptome data generated from infected Glycine max and Pratylenchus penetrans as a plant-nematode model is under investigation to elucidate the molecular mechanisms by which root-lesion nematodes interact with host plants. De novo assembly of P. penetrans contigs has been generated and analyzed. The total Pratylenchus retrieved sequences are under scrutiny. Mapping genomic coordinates of known RNAi lethal phenotypes in C. elegans onto such sequences will be used to develop dsRNAi candidate targets, and tested against P. penetrans. The identification of putative related-parasitism genes using BLAST search analysis will be also conducted against public genome datasets of plant-parasitic nematodes. Specific research directions will be evaluated and prioritized as they are encountered, i.e., high priority will be given to candidate genes that will most likely contribute to essential metabolic and parasitism pathways of the nematode. In addition, several cystatin and Bacillus thuringiensis crystal proteins have been cloned, and in planta overexpression of these genes will be evaluated against P. penetrans. The most promising candidates will be used to develop resistant lily plants. Additional Approach: Analysis of alfalfa samples received from collaborators will be analyzed using PCR-mediated amplification of a segment of the 16S rRNA gene with phytoplasma-universal primers, followed by implementation of the iPhyClassifier, a computational tool designed for taxonomic assignment and classification of phytoplasmas. Additional genomic markers will be analyzed based on results from study of ribosomal RNA genes. Comprehensive transcriptomic and functional analysis of alfalfa accessions resistant and susceptible to disease-causing pathogens. Additional Approach: Transient expression of genes involved with nematode resistance and genes involved in nematode parasitism will be used to identify potential transcripts for control of the burrowing nematode.