ChemischeVerteidigung

MechanischeAbwehr

Hakenhaare Dornen

DornenHolz

Cyanogene Glykoside

Konstitutive(= präformierte)

Abwehr

Pelargonien

Poison Ivy (Rhus toxicodendron)

O OO

O

O OO

O OO

OCH3

O OO

OCH3

OCH3

isoimperatorin oxypeucedanin

peucedanin 8-methoxypeucedanin

limonene

Asclepias syriaca

cardenolides

Avoidance by horses

Tetraopes beetles chew the leaves and sequester the cardenolides;their red warning color aims to indicate the impalpability to birds

(aposematic warning colorization)

Monarch butterfly

Larvae

A naive bluejay who has never before in his life encountered a monarch

Apparently programmed genetically to remove the “inedible” (or no food value?) wings of a butterfly, the naive bluejay does just exactly that.

Once the monarch has been de-winged, it swallows the monarch’s body.

A few minutes (seconds?) after swallowing the monarch butterfly body, the bluejaybegins to show a strong alarm reaction. All is not well. The feathers begin to stand on end, and it looks askance at the world.

The end ….

When the bird’s gut perceived the cardiac glycosides (origin in the milkweed), its immediate protective reaction was to vomit up the gut contents.

Chrysomelid beetle larvae

Adult

Clerid beetle, a carnivorous Batesian mimic

A Mullerian mimic, the ladybird beetle, makes its own defense chemicals,but the similarity with aposematic warning coloration of other beetles presents an advantage as the similarly-colored beetles are generally avoided by birds

InduzierteAbwehr

Sorghum and infection by Colletotrichum graminicola

O+HO

OH

OH

O+HO

OH

OH

OH

Apigenidin

Luteolinidin

Phytoalexins:

Low molecular compounds that are synthesized after exposure to microbial invasion.

Hypersensitive response results in a localized cell death reaction

Recent insights point to the mitochondrium as central player in programmed cell death

a, Disease lesion on a leaf of an empty-vector control alfalfa plant 10 days afterinfection with Phoma medicaginis (fungal hyphae and reproductive structures(pycnidia) are stained blue against the background of the leaf that has been cleared ofchlorophyll). b, Lesion of identical age on a plant that had been transformed with agrapevine stilbene-synthase gene under control of the cauliflower mosaic virus 35Spromoter. Such plants constitutively accumulate a glucoside of the novel phytoalexinresveratrol (structure indicated) and exhibit vastly reduced fungal development.

c, Lesions of Phoma medicaginis 5 days post-inoculation on leaves of alfalfa plants transformed with an empty-vector control construct. d, Lesions of identical age on plants constitutively expressing an alfalfa IOMTtransgene from the 35S promoter. The endogenous IOMT genes, and the other genesof the isoflavonoid pathway, are not constitutively expressed, but are induced afterfungal infection. The high expression of IOMT during the early stages of the response tothe fungus results in more rapid production of the endogenous phytoalexin medicarpin(structure indicated) and consequent reduction in disease severity.

Salicylsäure und Thermogenese

Fig. 3. Diversity of plant oxylipins formedin response to biotic aggressions. Aftermobilization by lipid acyl hydrolases (LAHs)from structural lipids, free fatty acids can beoxidized by at least three primary enzymaticsystems (shown in color boxes), the bestknown being the lipoxygenase (LOX)pathway. LOXs generally introduce molecularoxygen onto carbon 9 or 13 (and are referredto as 9- or 13-LOX) in C18 unsaturated fattyacids, leading to 9- or 13-specific derivatives.LOX-generated fatty acid hydroperoxides mayenter sub-branches, generating antimicrobial,cytotoxic, or signalingcompounds. The profile of oxylipins formeddepends on the enzymatic equipment of eachplant species and on the type of stress that isencountered. In addition, a series of nonenzymatically derived, prostaglandin-likecompounds (phytoprostanes) are formedunder oxidative stress upon wounding orpathogen attack. AOS, allene oxide synthase;DES, divinyl ether synthase; EAS, epoxyalcohol synthase; FA, fatty acid; HPL,hydroperoxide lyase; LOX, lipoxygenase;a-DOX, a-dioxygenase.

„Chemische Bomben“

Phytohormone

Nyctinastische Bewegungen