Plant Path Lab 12

Card Set Information

Author:
wsucoug12
ID:
312332
Filename:
Plant Path Lab 12
Updated:
2015-12-01 18:36:49
Tags:
Plant Path Lab 12
Folders:

Description:
Plant Path Lab 12
Show Answers:

Home > Flashcards > Print Preview

The flashcards below were created by user wsucoug12 on FreezingBlue Flashcards. What would you like to do?


  1. List the Two groups of Plant disease caused by viruses
    • 1. Mosaics & mottles
    • 2. Yellows
  2. Characteristics of Mosaic and mottle viruses:
    • Virus distributed throughout plant
    • Non-persistent or semi-persistent
    • transmission
    • Mechanical transmission
  3. Characteristics of Bean common mosaic virus and Bean yellow mosaic virus
    • Potyvirus group
    • ssRNA, flexuous rods
    • • Closely related
    • cross-protection occurs
    • • Mechanically transmissible
    • • Non-persistent aphid transmission
    • • Seed transmission - BCMV
  4. How to control BCMV & BYMV
    • Control aphid vectors
    • Remove alternative hosts
    • BCMV
    • Healthy seed
    • Genetic Resistance
  5. Characteristics of Yellows diseases:
    • Pathogen in phloem or xylem
    • • Persistent transmission
    • some propagative
    • • Not mechanically transmissible
  6. Why Study Transmission of Viruses?
    • Experimentally, transmission of virus is an important component of recognition.
    • o Economic impact is relative to transmission efficiency and crop lifetime.
    • o Such knowledge is generally an important component of control measures.
    • o Virus-vector relationships are of considerable biological interest.
    • o Certain methods are essential for effective laboratory maintenance of viruses.
  7. How are viruses transmitted?
    • Grafting
    • • Dodder
    • • Plant propagules
    • – True seed and pollen
    • – Propagation materials
    • • Soil-inhabiting organisms
    • – Fungi, plasmodiophorids & nematodes
    • • Arthropods (insects and arachnids –mites-)
  8. Virus transmission by plant propagules
    • – True seed
    • •Seed transmission requires invasion of the
    • embryo, and this occurs either by:
    • •1) direct invasion of the embryo after
    • fertilization or,
    • •2) by indirect invasion of zygotic embryos
    • through the fusion of infected gametes during fertilization.
  9. Virus transmission by Soil-inhabiting organisms
    • – Fungi
    • • Chytridiales
    • Olpidium brassicae Tobacco necrosis virus (TNV)
    • – Plasmodiophorids
    • • Polymyxa graminis
    • Wheat yellow mosaic virus (WYMV)
    • • Spongospora subterranea f. sp.
    • subterranea (SSS)
    • Potato mop top virus (PMTV)
    • Nematodes
    • Nepoviruses
    •  Longidorus spp.
    •  Paralongidorus spp.
    •  Xiphinema spp.
    • Tobraviruses
    •  Trichodorus spp.
    •  Paratrichorus spp.
  10. Mechanical Transmission of viruses:
    • =Manually transmitting a virus from one infected
    • plant to another (healthy) plant
    • •Possible ONLY in case of viruses that ARE
    • mechanically transmissible
    • •Example of a mechanically transmissible virus:TMV
    • •Example of a mechanically NON-transmissible
    • virus: Potato leaf roll virus
    • =Manually transmitting a virus from one
    • infected plant to another (healthy) plant
    • •Why manual effort?
    • •Virus are not capable of ‘active’ entry
    • (unlike most fungi and bacteria)
    • •Viruses ‘depend’ on ‘passive’ modes of entry
    • (vectors, mechanical means such as cutting
    • tools).
  11. What are the Steps in Mechanical Transmission
    • •Grinding infected material in a suitable
    • buffer*
    • •*The buffer has to keep the virus from
    • getting denatured or destabilized (loss of
    • infectivity)
    • •Most commonly used buffer is neutral 0.05
    • M phosphate buffer
    • •Reducing agents such as mercaptoethanol,
    • sodium sulfite help preserve the infectivity
    • of the inoculum
    • Carborundum or Celite are commonly used
    • as abrasives (to create tiny wounds on leaf
    • surface prior to application of the inoculum
    • on healthy plants
    • •Extract is gently rubbed on the dusted
    • leaves of healthy plants
    • •Excess inoculum is washed off with water
    • •Plants kept at desirable temperature and
    • lighting conditions in a greenhouse
    • • Plants are observed on a regular basis for
    • symptom development
    • •Depending on the virus and host it may take 5 days to weeks before symptoms appear
  12. How does BCMV survive?
    Survives in seed or perennial legume hosts
  13. How does BYMV survive?
    Survives only in perennial hosts
  14. Characteristics of Barley yellow dwarf virus (BYDV)
    • Luteovirus group
    • • ssRNA, spherical
    • • Persistent, non-propagative transmission by
    • aphids
    • • No mechanical or seed transmission
  15. How to control BYDV
    • Modify seeding date
    • • Resistance
    • barley, rye & oats
    • • Control aphid vectors
    • • Eliminate “green bridge”
  16. What is the function of carborundum?
    Used as an abrasive to help in grinding and causing wounding for viral infection
  17. What is the purpose of using phosphate buffer in grinding?
    To keep the virus from denaturing and help keep its infectivity
  18. What is TSWV?
    Tomato Spotted wilt virus
  19. What is the Barley Yellow dwarf virus green bridge?
    Winter wheat from sept to august, goes into spring wheat, spring barley or corn, then  back into winter wheat

What would you like to do?

Home > Flashcards > Print Preview