Plant Defense Mechanisms
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Questions and Answers

What type of defense mechanism do plants have to prevent pest attacks?

  • Physical barriers (correct)
  • Biological barriers
  • Chemical barriers (correct)
  • Environmental barriers

    • What is the main purpose of using Metarrhizium anisopliae in pest control?

  • To control plant diseases
  • To control insect pests (correct)
  • To increase crop yield
  • To control weeds

    • Which of the following microorganisms is used to control plant parasitic nematodes?

  • Trichoderma
  • Bacillus amiloliquefaciens
  • Paecilomyces lilacinus (correct)
  • Beauveria bassiana

    • What is the purpose of using Bacillus thuringiensis (Bt) in pest control?

    <p>To control insect pests</p> Signup and view all the answers

    What is the purpose of suberized cells in plant defense?

    <p>To form a physical barrier against pests</p> Signup and view all the answers

    What is the purpose of the Bt toxin in genetically modified crops?

    <p>To provide insect resistance</p> Signup and view all the answers

    What is the name of the genetically modified papaya that is resistant to papaya ringspot virus?

    <p>Sunup</p> Signup and view all the answers

    Which of the following microorganisms is used to control giant reed weed?

    <p>Arundo gall wasp</p> Signup and view all the answers

    What is the name of the company that developed the Round-up Ready canola?

    <p>Monsanto</p> Signup and view all the answers

    What is the function of phytoalexins in plant defense?

    <p>To respond to fungal infections</p> Signup and view all the answers

    What is the purpose of genetic pest control method?

    <p>To control pests through genetic manipulation</p> Signup and view all the answers

    What is the main purpose of using Trichoderma in pest control?

    <p>To control plant diseases</p> Signup and view all the answers

    What is the purpose of systemic acquired resistance (SAR) in plants?

    <p>To provide long-term resistance to pathogens</p> Signup and view all the answers

    Which of the following techniques is used in genetic pest control method?

    <p>Causing reproductive sterility in pests</p> Signup and view all the answers

    What is the name of the genetically modified tomato that has delayed ripening?

    <p>FlavrSavr</p> Signup and view all the answers

    What is the purpose of using Colletotrichum gloeosporioides in pest control?

    <p>To control sensitive jointvetch</p> Signup and view all the answers

    What is the consequence of water hyacinth growth in tropical freshwater without CBC?

    <p>Freshwater being rendered useless</p> Signup and view all the answers

    Which of the following is an example of an augmentative approach in biological control?

    <p>Trichogramma spp. used against many Lepidopteran insect pests</p> Signup and view all the answers

    What is the main reason for using biological control agents?

    <p>Increasing resistance against pesticides</p> Signup and view all the answers

    Which of the following is a consequence of the overuse of pesticides?

    <p>Increased dose and frequency of pesticide use</p> Signup and view all the answers

    What is the name of the aquatic weed that is considered the world's worst?

    <p>Water hyacinth</p> Signup and view all the answers

    What is the term for releasing natural enemies periodically or seasonally to reestablish a balance?

    <p>Inoculative approach</p> Signup and view all the answers

    What is the consequence of using pesticides excessively?

    <p>Increased problems with residues in fruits and vegetables</p> Signup and view all the answers

    What is the term for the massive production and release of natural enemies to control pests quickly?

    <p>Inundative approach</p> Signup and view all the answers

    What is a crucial geographical requirement for an eradication zone?

    <p>Natural barriers or defensible borders</p> Signup and view all the answers

    What is a limitation of the Sterile Insect Technique (SIT) due to the target pest's behavior?

    <p>Native females may recognize and refuse to mate with sterile males</p> Signup and view all the answers

    What is an economic limitation of the Sterile Insect Technique (SIT)?

    <p>The cost of rearing, sterilizing, and releasing large numbers of insects</p> Signup and view all the answers

    What is a characteristic of the lab-reared and sterilized male insects used in the Sterile Insect Technique (SIT)?

    <p>They are equally or more competitive than native males in mating with native females</p> Signup and view all the answers

    What is required for the successful implementation of the Sterile Insect Technique (SIT)?

    <p>Knowledge of the pest's reproductive behavior, population dynamics, dispersal, and ecology</p> Signup and view all the answers

    What is the primary function of the Cry protein in Bacillus thuringiensis?

    <p>To break down in the insect gut and release the toxin known as delta endotoxin</p> Signup and view all the answers

    What is an alternative genetic strategy to the Sterile Insect Technique (SIT)?

    <p>Inherited/Delayed Sterility</p> Signup and view all the answers

    What is the purpose of incorporating a virus coat protein in genetic engineering for disease resistance?

    <p>To cross protect the host plant from viral diseases</p> Signup and view all the answers

    What is the term for a gene moved from one non-closely related species to another?

    <p>Transgenic</p> Signup and view all the answers

    What was the first genetically engineered crop plant?

    <p>Tobacco</p> Signup and view all the answers

    What is the definition of pesticides?

    <p>Any substance or product, including active ingredients, adjuvants and pesticide formulations, intended to control, prevent, destroy, repel or mitigate directly or indirectly, any pest</p> Signup and view all the answers

    What is the name of the toxin released by the Cry protein in Bacillus thuringiensis?

    <p>Delta endotoxin</p> Signup and view all the answers

    What is the purpose of using Plantibodies in genetic engineering for disease resistance?

    <p>To provide disease resistance to host plants</p> Signup and view all the answers

    What is the year when Bacillus thuringiensis was approved for commercial sale?

    <p>1985</p> Signup and view all the answers

    What is the function of 2-5A synthetase in genetic engineering for disease resistance?

    <p>To provide disease resistance to host plants</p> Signup and view all the answers

    What is the purpose of incorporating a glyphosate degrading enzyme in genetic engineering for herbicide resistance?

    <p>To degrade glyphosate in the soil</p> Signup and view all the answers

    Study Notes

    Evolutionary Arms Race

    • Plant defense mechanisms against pests:
      • Physical barriers: thick, waxy cuticle, long, dense trichomes, sticky trichomes, suberized (corky) cells
      • Chemical barriers: secondary metabolites (thousands of known compounds with varied and complex chemistry)
    • Pests can develop resistance to plant defense mechanisms, leading to an evolutionary arms race

    Genetically Modified Crops

    • Examples of genetically modified crops:
      • Canola with herbicide resistance (Glyphosate) - Round-up Ready
      • Corn with herbicide resistance (Glyphosate) - SeedLink
      • Flax with herbicide resistance (Sulfonylurea) - CDC Triffid
      • Soybeans with herbicide resistance (Glufosinate)
      • Corn with insect resistance (Bt toxin) - NatureGard
      • Cotton with insect resistance (Bt toxin) - Bollgard
      • Potatoes with insect resistance (Bt toxin) - NewLeaf
      • Squash with disease resistance (Watermelon, zucchini, and cucumber mosaic viruses)
      • Papayas with disease resistance (Papaya ringspot virus) - Sunup, Rainbow
      • Tomatoes with delayed ripening - FlavrSavr

    Biological Control

    • Water hyacinth (Eichhornia crassipes) is the world's worst aquatic weed, threatening freshwater flora and fauna, increasing disease vectors, and hampering hydroelectric power, transport, and water supply.
    • Biological control agents used to control water hyacinth:
      • Mottled water hyacinth weevil (Neochetina eichhorniae)
    • Approaches to implementing biological control agents:
      • Periodical mass release of beneficials (augmentation approach)
        • Inoculative approach: releasing natural enemies to reestablish balance
        • Inundative approach: massive production and release of natural enemies to control pests quickly

    Biocontrol Methods

    • Reasons to use biocontrol methods:
      • Increasing resistance against pesticides
      • Higher dose and increased frequency of pesticide use
      • Problems with residues in fruits and vegetables
    • Examples of biocontrol methods:
      • Insect pathogens: Metarrhizium anisopliae (green muscardine fungus), Beauveria bassiana (white muscardine fungus), Bacillus thuringiensis (Bt) against corn borer
      • Microorganisms against plant pathogens:
        • Fungus (Trichoderma) against various plant pathogens
        • Fungus (Paecilomyces lilacinus) against nematodes
        • Bacillus amiloliquefaciens against many plant diseases
      • Microorganisms against weeds:
        • Phytophthora palmivora against strangler vines
        • Collectotrichum gloeosporoides f.sp.aeschenomene against sensitive jointvetch
        • Arundo gall wasp against giant reed weed

    Genetic Manipulation of Pests

    • Genetic pest control methods:
      • Causing reproductive sterility
      • Incorporating new genes or alleles into the pest population (deleterious) or crop (resistance)
    • Limitations of Sterile Insect Technique (SIT):
      • Resistance: native females may refuse to mate with sterile males
      • Economics: high cost of rearing, sterilizing, and releasing large numbers of insects
      • Desirability of sterile males: lab-reared males may become less competitive over generations
      • Knowledge about pest: understanding pest behavior, population dynamics, dispersal, and ecology
      • Timing: synchronizing lab-reared insect development with wild population development
    • Alternative genetic strategies:
      • Inherited/Delayed Sterility: released insects are fertile but their progeny are sterile
      • Genetic Engineering in Pest Management:
        • Utilizes biotechnology to make plants resistant to specific pests
        • Examples: Bt crops, herbicide-resistant crops, disease-resistant crops

    Genetic Engineering in Pest Management

    • Definition of terms:
      • Transgenic: gene transfer between non-closely related species
      • Cisgenic/Intragenic: gene transfer within same species or closely related species
      • Subgenic: gene editing to amplify, delete, insert, silence, or repress genes
    • First genetically modified crop: tobacco, approved in 1985
    • Bacillus thuringiensis (Bt) produces crystalline (Cry) protein, which breaks down in insect gut and releases toxin
    • Herbicide resistance:
      • Incorporating soil bacterium gene that produces glyphosate-tolerant EPSPS
      • Incorporating soil bacterium gene that produces glyphosate-degrading enzyme
    • Disease resistance:
      • Using virus coat protein as cross-protectant for host plant
      • Using Plantibodies
      • 2-5A synthetase, a class of proteins of mammalian origin, for engineering plant virus resistance

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    Description

    This quiz covers the different defense mechanisms that plants have evolved to protect themselves from pests, including physical and chemical barriers. Learn about the various ways plants defend themselves!

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