Self And The Phenomenon Of Life: A Biologist Examines Life From Molecules To Humanity

106 Self and the Phenomenon of Life

b2726 Self and the Phenomenon of Life: A Biologist Examines Life from Molecules to Humanity “9x6”

called “effectors” in order to sabotage the defense within the plant cell.
To counter this attack, plants have produced, over evolution, special types
of proteins called NB-LRR that are able to recognize the “effectors” and
mount a second defense response called “ETI,” leading to the same defense
outcome as seen in the original pathway.21,22 Over many generations, this
evolutionary “arms race” between the invaders and the hosts resulted in a
great variety of highly specific “effectors” and NB-LRR proteins.

5.8 Rejection of Self during Mating

Many flowering plants prevent inbreeding by developing a strategy to
distinguish self from non-self between the male and female sex organs,
when both are present in the same plant (hermaphrodites). The recogni-
tion is at the molecular level (protein-protein interaction) and involves an
intricate self-incompatibility mechanism, wherein pollens from the same
plant are recognized and rejected by the pistil (female part of a flower),
controlled by determinants encoded in the genes. Self-fertilization is
thereby avoided.^23

Notes and References

1. These secondary plant metabolites frequently have industrial and pharma-
   ceutical uses and are commonly known as “natural products.”


2. Weng J-K, Phillipe RN, Noel JP. (2012) The rise of chemodiversity in
   plants. Science 336: 1667–1670.


3. Karban R, Baldwin IT, Baxter KJ, et al. (2000) Induced resistance in wild
   tobacco plants following clipping of neighboring sagebrush. Oecologia
   125: 66–71.


4. Cost C, Heil M. (2006) Herbivore-induced plant volatiles induce an
   indirect defence in neighboring plants. J. of Ecology 94: 619–628; Heil M,
   Bueno JCS, (2007) Within plant signaling by volatiles leads to induction
   and priming of an indirect plant defense in nature., Proc Natl Acad Sci USA
   104: 5467–5472.


5. Karban R, Shiojiri K, Ishizaki S, et al. (2013) Kin recognition affects plant
   communication and defense. Proc R Soc B 280: 20123062.