The submersed aquatic plants Eurasian watermilfoil (Myriophyllum spicatum) and Hydrilla (Hydrilla verticillata) are a nuisance in waterways of the U.S. Biological control with plant pathogens is a proven method for the management of aquatic plants. An attempt was made to identify lectins of Eurasian watermilfoil and Hydrilla tissues in hopes of characterizing a means of specific attachment to fungal pathogens on the target plants. Four fungal isolates (Fusarium roseum, Macrophomena phaseolina, Colletotrichum gloeosporioides and Mycoleptodiscus terrestris) were evaluated for the ability to attach and infect Eurasian watermilfoil and Hydrilla. Lectins were isolated from total protein by affinity chromatography. Lectin activity was evaluated for agglutination of the human ABO blood groups and fungal mycelium. Eurasian watermilfoil lectin was evaluated for its ability to inhibit fungal growth. No specific attachment was detected on Hydrilla tissues. F. roseum attached specifically to Eurasian watermilfoil tissues. All four fungi were pathogenic on Hydrilla tissues after seven days in test tube bioassays. All but F. roseum were pathogenic on Eurasian watermilfoil. Lectins specific for $\alpha$-L-fucose were isolated from both Eurasian watermilfoil and Hydrilla. The Eurasian lectin has a molecular weight of 48 Kd. The Hydrilla lectin is a complex of two proteins with molecular weights of 67 Kd and 50 Kd. Both Eurasian and Hydrilla lectins agglutinated type O red blood cells. Hydrilla lectin has no affect on mycelial suspensions of the four fungi, while Eurasian lectin agglutinated all fungi except M. phaseolina. The existence of lectins in the aquatic plants Hydrilla verticillata and Myriophyllum spicatum has been demonstrated. Plant lectins play a role in plant-pathogen association through attachment and/or recognition. Where attachment is specific and the lectin agglutinates the fungus, disease resistance occurs. This evidence supports the theory that recognition through plant lectins is a host defense mechanism.
| Identifer | oai:union.ndltd.org:UMASS/oai:scholarworks.umass.edu:dissertations-7441 |
| Date | 01 January 1991 |
| Creators | Theriot, Edwin Anthony |
| Publisher | ScholarWorks@UMass Amherst |
| Source Sets | University of Massachusetts, Amherst |
| Language | English |
| Detected Language | English |
| Type | text |
| Source | Doctoral Dissertations Available from Proquest |
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