Transcript Plant Defense Responses

Plant Defense Responses
Elisa Russo & Ben Strozyk
2011
The Attack on Plants
• Viruses, bacteria, fungi, animals, and other
plants can attack
• They attack by spore germination, hyphae
growing through cell walls, and hyphae
differentiating into specialize haustoria
Responses by Plants
• cyanogenic glycosides
- break down into cyanide when
ingested, which stops electron
transport and blocks cellular respiration
• Used in plant defense against
attack. Releases hydrogen
cyanide after tissue
disruption. ...
Responses by Plants
• Tannins
Bind to and inactivate proteins
• Alkaloids
Plant-based substances such as nicotine,
cocaine, caffeine, and codeine that can
have medical uses but also be addictive or
poisonous in higher doses
Responses by Plants
• Alleopathy occurs when a chemical signal
secreted by the roots of one plant blocks
the germination of nearby seeds or inhibits
the growth of a neighboring plant.
– Ex. Think tree wanting to get sunlight
Human Benefit From Plants
• Secondary Metabolites
chemical compounds produced in plants
which do not play a role in the primary
functions, such as photosynthesis and
respiration.
(think photosynthesis)
Human Benefit from Plants
• Phytoestrogens are found in plants and
have a very similar molecular composition
as the hormone estrogen. During pre
menopause, when the natural estrogen
production falls dramatically, the collagen
level also drops. This is the main reason
why phytoestrogens are used in cosmetic
treatments
• Ex. Soy milk
Nature Working Together
• When some plants are attacked/wounded
they release compounds to attract other
animals to come fight the attacker off
• EX: -Parastoid Wasps provide protection from
herbivory: A caterpillar eating a leaf triggers a
wound response, releasing a volatile compound
• -The wasp is attracted to this compound and
lays eggs in the caterpillar
• - Wasp Larvae consume the caterpillar, and the
leaf is left unharmed
Systemic Responses
• Wound responses – if leaf is in injured plant
releases substance as a proteinase inhibitor
(provent virus)
• Pathogenic Response
- Gene for gene recognition leads to cell death
which seals off wounded tissue
- Systematic Aquired Resistance- induced by
signals to allow plant to respond more quickly.
Uses Salicylic Acid and Jasmonic Acid