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HOR 415 Exam 2
| Term | Definition |
|---|---|
| Characteristics of Bacteria (6) | - prokaryotic - single celled - some motile - cell wall coated with EPS - facultative parasites - reproduce by binary fission |
| How is dilution plating utilized for bacteria? Why? | Bacteria is swiped onto a PGA dish and then incubates. Smaller colonies should form from the swipe which makes it easier to ID and examine. |
| CFU | Colony Forming Unit |
| Typical symptoms of bacterial diseases (7) | leaf spots, blights, soft rots of fruits and roots, wilts, overgrowth, scabs, cankers |
| Unholy Trinity of Bacteria (and what they cause) | Pseudomonas spp. - bacterial speck Xanthomonas spp. - black rot of brassicas Erwinia spp. - fire blight of apples |
| Agrobacterium tumefaciens | Crown gall of cucurbits |
| Mollicutes structure | pleomorphic (no consistent shape) and have no cell wall |
| Xylem-Limited Bacteria (1) | Xylella fastidosa |
| Phloem-Limited Bacteria (2) | Phytoplasmas, Spiroplasmas |
| Characteristics of Nematodes (6) | - worm-like, serpentine - bilateral symmetry - nonsegmented roundworms - mostly aquatic - parthenogenic (females do not need to be fertilized) - anhydrobiosis or cryptobiosis |
| Endoparasitic Nematode | Pathogenic |
| Ectoparasitic Nematode | Pest-like |
| Endoparasitic Nematode examples (2) | Root-Knot and Cyst |
| Ectoparasitic Nematode examples (4) | Dagger, Ring, Sting, and Stubby Root |
| Typical symptoms of nematodes (3) | wilting, stunting, yellowing |
| Root-Knot Nematode | Meloidogyne spp. |
| Cyst Nematode (2) | Heterodera spp. and Globodera spp. |
| Ring Nematode (2) | Criconemoides spp. and Mesocriconema spp. |
| Sting Nematode | Belonolaimus spp. |
| Stubby-Root Nematode (2) | Paratrichodorus spp. and Trichodorus spp. |
| Dagger Nematode | Xiphinema spp. |
| Foliar Nematode | Aphelenchoides spp.) |
| Entomopathogenic | Feeds on insects, "good guys" |
| Entomopathogenic nematode examples (2) | Heterohabditis and Steinernema |
| Unipartite | One chromosome |
| Multipartite | Many chromosomes |
| Tripartite | Three chromosomes |
| Tobacco mosaic virus (TMV) symptom | mosaic |
| Bean golden mosaic virus symptom | mosaic |
| Oat blue dwarf virus symptoms | stunting and dwarfing |
| Aster yellows phytoplasma symptom | yellowing |
| Tomato spotted wilt virus symptom | ringspot |
| Tulip breaking virus symptom | flower break |
| Bean common mosaic virus symptoms | leafroll and mosaic |
| Tobacco etch virus symptom | fruit deformation |
| Koch's Postulates for Viruses Step 1 | Describe the symptoms and signs of a disease. |
| Koch's Postulates for Viruses Step 2 | Purify the virus and note its characteristics. |
| Koch's Postulates for Viruses Step 3 | Inoculate a healthy plant with the purified virus, and recreate the same disease originally described. |
| Koch's Postulates for Viruses Step 4 | Purify the virus characterized in Step 2 from the inoculated plant. |
| Bioassay | inoculating a plant to test for viral pathogenicity |
| ELISA | (Enzyme-Linked Immunosorbent Assay) immunological/serological test |
| PCR | (Polymerase Chain Reaction) molecular/genetic test that amplifies a piece of virus to sequence/ID |
| Immune to infection... | if the virus does not multiply in the plant. |
| Resistant to infection... | if it restricts the virus multiplication or spread. |
| Tolerant to infection... | if it produces a good yield in spite of unrestricted virus infection. |
| Susceptible to infection... | if it is unable to restrict virus multiplication or spread and shows obvious symptoms including yield loss. |
| HR | (Hypersensitive Response) when a plant loses an infected limb. Incompatible Host. |
| LL | (Local Lesions) when it kills off portions of itself to kill off the virus present in those areas. Compatible Host. |
| Holoparasites | Parasites of xylem and phloem, totally dependent on host, usually yellowish with small or scaly leaves |
| Hemiparasites | Parasites of xylem, use water and minerals from host but are not dependent, usually green and leafy |
| Mycoheterotrophs | mostly non-photosynthetic plants that obtain nutrients from a host plant through a fungus |
| Method by which parasitic plants gain entry into host | punching through with a haustorium |
| Examples of parasitic plants (3) | broomrape, dodder, witchweed |
| Broomrape | (Orobanche spp.) root parasite, holoparasite, hosts: sunflower, tobacco, vegetable crops |
| Dodder | (Cuscuta spp.) stem parasite, holoparasite, wide host range |
| Witchweed | (Striga spp.) root parasite, hemiparasite, hosts: corn, legumes, rice, sorghum |