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