Silent Spring

1962

DDT, Mercurials

Book brought on more awareness of the possible adverse effects of pesticides

Millardet

Bordeaux Mixture

Grape Vines exposed to downy mildow but treated with mixture still retained most of their foliage.

Koch

Koch's Postulates

Spontaneous Generation

Proved that microoranims were produced from preexisting microorganisms.

1. Host

2. Pathogen

3. Environment

4. Time

Fungal Groups

Chromistic Algae

Ooomycota

elongated nonseptate mycelium, biflagellate zoosporangia, oospores

Fungal Groups

Lower Fungi

Myxomycota (slime molds)

may be related to protozoa

Fungal Groups

Lower Fungi

Chytrids

Have zoospores with a single posterior flagellum, round or elongated mycelium

Fungal Groups

Higher Fungi

Zygomycetes

Produce nonmotile asexual spores in sporangia, resting spore is a zygospore

Fungal Groups

Higher fungi

Ascomycotina = ascomycetes

produce sexual spores, ascospores, generally in groups of 8 in an ascus. Produce nonmotile spores (conidia)

Fungal Groups

Higher Fungi

Basidiomycotina = basidiomycetes

produce sexual spores, basidiospores, externally on a  basidium

Fungal Groups

Higher Fungi

Deutermycotina = deutermycetes

or

Fungi imperfecti

is an organism that uses dead organic matter for food

any type of reproduction not involving the untion of gametes or meiosis.

(Asexual spores are produced in a sac called sporangium)

Sexual

Deuteromycete:

Conidium

Part of Deuteromycete

an asexual fungus spore formed from the end of a conidiophore

Deuteromycete:

Conidiophores

Part of Deuteromycete:

a specialized hypha on which one or more conidia are produced.

Parts of Ascomycotina

Ascus

Parts of Ascomycotina

Ascospores

Parts of Basidiomycota

Basidium

Parts of Basidiomycota

Basidiospores

Parts on Oomycota

Antheridium

Parts on Oomycota

Oogonium

Parts on Oomycota

Oospore

Parts on Oomycota

Zoospore=Oomycota

Spores (Asexual)

Zoospores

Spores (Asexaul)

Conidia

Spores (Asexual)

Chlamydospore

Spores (Asexual)

Pycnidia

Spores (Sexual)

 Zygomycetes

B) Zoosporangia

B)Asporangium which containting or producing zoospores

Spores (Sexual)

A) Ascomycetes

B) Apothecium

A) group of fungi producing their sexual spores, ascospores, within asci (ascus)

B) an open cup- or -saucer shaped ascocarp in some ______(blank is A)

Spores (Sexual)

Basidiomycetes

Water mold (Oomycete) Phytophthora infestans

The year the water mold came to Irland, Ireland experienced unusually cool, moist weather, in which the blight thrived. Wiped out almost all of the potatoes. No diversity in potato species.

BACTERIA

Morphology

Filamentous

Thread like

(Streptomyces - potato scab)

BACTERIA

Morphology

Pleomorphic

lose their shape

(mycoplasmalike organisms- spiroplasmas, mollicutes, phytoplasmas)

Fastidious Vascular Bacteria

Generally rod-shaped cells. Bounded by a cell membrane and a cell wall.

Induce virus like symptoms (discovered in 1960s)

Transmitted by leaf-hoppers

Inhabits Phloem, immune to Penicllin.

Aster yellowing, and Coconut lethal yellowing

BACTERIA

Morphology

Rod-Shaped

BACTERIA

Morphology

Rod-Shaped

Agrobacteria

BACTERIA

Morphology

Rod-Shaped

Clavibacter

BACTERIA

Morphology

Rod-Shaped

Erwinia- What damage does it cause?

BACTERIA

Morphology

Rod-Shaped

Pseudomonas/Ralstonia

What type of damage does it cause?

Pseudomonas/Ralstonia have what type of bacteria morpholgy?

Cause southern bacterial wilt, moko

BACTERIA

Morphology

Rod-Shaped

Xanthomonas

What type of Damage?

Xanthomonas has what type of Bacteria Morhology?

Citrus Canker

BACTERIA

Morphology

Rod-Shaped

Xyella

Formally Rickettsialike(similiar to bacteria in most respects but generally capable of multiplying only inside living host)

Pierce's disease of grape

fastidous

Aflagellate

Responds to Penicllin

Xylem-Inhabiting

Transmiited by Leaf Hopper

BACTERIA

Morphology

Rod-Shaped

Rhizobium

nitrogen fixing

legume associated

soil-inhabiting

Benefits plant!!! (not all parasites are harmful)

Symptoms of Bacteria

Witches Broom

Symptoms of Bacteria

Wilt

Symptoms of Bacteria

E. tracheiplila (southern wilt)

Symptoms of Bacteria

Spots, blights

Symptoms of Bacteria

a dieases characterized by general and rapid killing of leaves, flowers, and stems.

Symptoms of Bacteria

Rots

Symptoms of Bacteria

the softening, discoloration, and often distegration of a succulent plant tissue as a result of fungal or bacterial infection

Bacteria Transmission

Fastidious

Cannot be cultured

Xylella-genus found in Xylem of Plant

Transmitted by Xylem-feeding Leafhoppers

Bacteria Transmission

Fastidious Phloem-limited Bacteria

Phytoplasmas and spiroplasmas (microplasmas)

Transmitted by Leafhoppers

Persistent pathogens-retianed long time by insect

Pathogen replicates inside host

Pathogen must be able to move from insect into the plant phloem.

Virus Transmission

Vegetative Propogation

Grafting-cannot graft monocots (can only graft woody plants)

Division of canes, tubers.

Virus Transmission

Mechanical Transmission

Through Sap

Experimental (Carborundum)

Prunning toolds, hands

Virus Transmission

Seed and Pollen (Nature's Way)

Most are NOT tranmissted this way

Embryo infection (rarely very high & limited to certian viruses/species)

Seed Coated Infection (rare and associated with stable viruses such as tobamovirus)

Virus Transmission

Arthropod Transmission

Group Assoicated

This type of transmission normally has one carrier for the virus.

Tobamoviruses have no vector

Most Potyviruses are aphid borne

Most Geminiviruses are whitefly borne

Virus Transmission

Arthropod Transmission

Suctoral Inesects

"Worest Group" of Virus Tranmission

Target is almost always Phloem

Persistent (Circulative, species specific)

Non-Persistent (stylet borne, not species specific)

semi-persistent (species specific)

Virus Transmission

Arthropod Transmission

Thrips

Virus Transmission

Tospoviruses, esp. tomato spotted wilt

Virus Transmission

Arthropod Transmission

Beetles

Virus Transmission

Mostly Chyrsomelids

Virus Transmission

Other Vectors

Mites

Some Nematodes

Certain Mycomycetes-like fungi

Dodder

Many prokaryotes, and some lower eukaryotes also carry smaller circular molecules of DNA called...

It also carries genetic information but multiplies and moves independently of the chromosomel DNA.

What is Citrus Greening

Where did it come from?

How is it transmitted?

One of the most severe disease of Citrus. Causes reduced yeilds.

Located in Asia, from China to the Philippines, and Arabian Peninsula, and Africa.

Symptoms: smaller leaves, yellowing of leaves, and canopy, reduced foilage, severe dieback of twigs. Fruit is lopsided, fails to ripen, and instead remains green.

Spread by vegetative propagation and by two psyllid insects.

Antibiotics priduced by various species of Streptomcyces and are active against many bacteria and against all millicutes.

Also bind to bacterial ribosomes and inhibit protein synthesis.

Vine Replated to morning glory & sweet potato

No leaves, and roots modified as haustoria (or simple branched projection or hyphae into host cells that actas as an absorbing organ)

Plant that wrapes around a green plant and parasitizes it.

Wide host range and can spread some viruses.

Old world native

Roorts Modified into Haustoria

Green leaves non vining

Can be controlled by "Trap Crops"

Green leaves, roots modified into haustroria, parasitic epiphyte

Fruit is white, and when mature open and expelling seeds as far as 5 feet. Seeds adhere to branches

an ultamicroscopic, metabolically inert, infectious agent that replicates only within cells of living host, mainly bacteria, plants, and animals.

Composed of RNA, and DNA core, a protein coat, and in more complex types, a surrounding envelope.

No

Asking if Viruses and Viriods are living.

Classified into "groups" with members having serological and nucelotide sequence affinities.

Determined by the International Committe for the Taxonomy of Viruses. (ICTV)

Virus Groups

Vector (how they are transmitted) Relationships)

Cloesly related with groups.

E.g.: Almost all potyviruses are aphid-transmitted

All nepoviruses are nematode-transmitted

Tobamovirus

Rod-shaped, affects leaves, flowers, fruits, stunting. Kills Tropical Soda Apple. Systemically transmitted in Phloem. Sanitation is key in prevention.

NO Vectors! Mechanical Transmission through human contact...vegetative propagation.

Largest genus of plant viruses (Normally Plant name mosaic virus)

Rod-shaped, mosaics, mottling, chlorotic rings or color breaks on foliage, flowers fruit and stems. Stunting in young plants.

APHID VECTORS

Destroy volunteers, weeds around crop. Cultural controls like early planting and crop rotation, virus-free seeds!

Spherical shape

Thrips Vector

(Tomato Spotted Wilt Virus)

Not as explosive as sphid borne viruse

Vectors are Leafhoppers, Whitefly, or Treehoppers

This is a Virus

How are Viruses usually named?

Vernacrular

Viruses are usually named after the most conspicuous symptom they cause on the first host in which they have been studied.

E.g.: A virus causing a mosaic on tobacco is called tobacco mosaic virus.

This method is lacking, b/c the virus can show different symptoms on different plants.

Four Organisms capable of transmitting viruses.

This type of transmissioni s acomplished when an aphid searches for food. As the aphid probes for food it picks up the virus on the stylet.

Uninfected plants are infected when the aphid moves onto the new tissue and probes more tissue.

These viruses do not last very long on the vector

Mosaic, Mottle, Yellowing, and Stunting

Yellowing- a plant diesase characterized by yellowing and stunting of the host plants

Stunting- a plant diesase that causes dwarfing

Virus Transmission

Seed

Only a small portion of virus infected plants transmit the virus to the ______.

Legumes are susceptible

Virus Transmission

Nematodes

A) important in any situation where vegetative propagation is utilized.

B) Are important in Florida b/c of Florida's climate allowing many generations of aphids to persist throught most of the state every year.

C) Are important to florida, due to insects as vectors.

Steps involved in the DAS ELISA

ELISA-Enzyme Linked Immunosorbent Assay

Collect leaf infected leaf, liquefy leaf (green soup), seperate plant and viral parts by centrifuge.

Once Viral parts are seperated, inject into Rabbit. Rabbit then produces antibodies to this virus, and blood is collected from the Rabbit.

The rabbits blood is removed and you are left with antiserium.

Then put the antibodies in a test chamber, add virus samples. The virus that you are doing the assay on will stick to the antibodies, and others will wash away.

Color intensity- darker the color the more virus particles that were present.

Nummuerical Value- higher the value the more population of that particular value.

lower-less of a population.

Two test are run on the plants. A positive and negative.

Positive will always try to go for the highest value possible, and negetive the lowest (hopefully zero)

Once those numbers are defined it allows the research to determine if the population is high enough to cause alarm.

(Normal plants will not be zero for their negative, natural proteins, but if the number was 1.6 you would believe the plant to be infected)

React specifically with antigenic determinant of the injected antigen, they bind to a small portion of the antigen(virus).

The antiserum contains many antibodies which reacts with the antigen but at different surface locality.

How are Viroids different from Viruses

E.g.: They are stable, yet have no protein coat, how do they survive?

1) RNA is much smaller

2) Lacks protein coat

3) Seems to associate with cell nuclei

4) Survice in nature outside the host or dead plant material for few minutes to few months.

Their transmission is mechanical, overwinter in perennial hosts, which is the MAIN host for ALL of ______.

Are most viruses seed transmitted?

Situation with certian Legumes?

No, most viruses are not seed transmitted.

Most transmittion is through vectors, especially aphids.

Legume seeds are susceptible to virus transmission apparently to the virus/host interation.