Phytoalexins in defense against

pathogens

Biokimia Adaptasi 2013

Oleh:Pauline D. Kasi

(PBI/1032)S. Hafidhawati A.

(PBI/1044)

PPS Biologi UGM

PHYTOALEXINS

Phytoalexins : low molecular weight, anti-microbial compounds that are both synthesized and accumulated in plants after exposure to microorganisms or abiotic agents (Mert-Türk, 2002)Phytoalexins are compounds synthesized by plants in response to extrinsic stress such as microbial attack and physical injury (Ejike et.al., 2013)Phytoalexins secondary metabolites by phenylpropanoid, mevalonic acid, and polymalonic acid pathway

Inducer & signaling of phytoalexin

Microbial attack Elicitors : Induce

phytoalexin by mimicking a pathogen attack or other stress.

Signaling to camalexin : Jasmonic acid, Salysilic

acid, ROS

Phytoalexin toxicity

Phytoalexin was involved in defense against netrophic but not biotrophic pathogens, also resistance against hemibiotrophyEx: Camalexin play a role in resistance to the necrotophic fungi Alternaria brassicicola (black spot), but adapted to biotrophic Golovinomyces orontii (powdery mildew)

Camalexin biosynthesis and regulatory mechanisms

(Ahuja et.al., 2012)

Structures of selected phytoalexins

(Ahuja et.al., 2012)

(Ahuja et.al., 2012)

…(continued)

Arachidins, Resveratrol in peanut seed

Großkinsky et al., 2012

(Ahuja et.al., 2012)

Phytoalexins applicationSome phytoalexins have attracted relevant in human health promotion peanut phytoalexin as anticancer, antidiabetic and vasodilator effects (Boue et al., 2009; Holland & O'Keefe, 2010)Food preservatives in cereal foods crop (Ejike et al., 2013)

Phytoalexin from grapevine has anti-carcinogenic and anti-inflammatory (Smoliga, 2011)

References Ahuja, I., Kissen, R. & Bones, A.M. (2012). Phytialexins in

defense against pathogens. Trends in Plant Science 17(2) : 73-90

Boue, S.M., Cleveland, T. E., Carter-Wientjes, C., Shih, B. Y., Bhatnagar, D.,McLachlan, J.M., et al. (2009). Phytoalexin-enriched functional foods. Journal of Agricultural and Food Chemistry, 57: 2614–2622.

Großkinsky, D.K , Graaff, E. & Roitsch, T. (2012). Phytoalexin transgenics in crop protection—Fairy tale with a happy end?. Plant Science 195 : 54– 70

Holland, K. W., & O'Keefe, S. F. (2010). Recent applications of peanut phytoalexins. Recent Patents on Food, Nutrition & Agriculture, 2 : 221–232.

Smoliga, J.M. et al. (2011) Resveratrol and health – a comprehensive review of human clinical trials. Mol. Nutr. Food Res. 55 :1129–1141

Diskusi1. Pada organ apa fitoalexin disentesis?

(Darussalam)Fitoaleksin disintesis pada hampir semua organ tanaman, dimana ada serangan patogen yang terjadi. Semakin dekat dengan tempat terjadinya serangan patogen, konsentrasi fitoaleksin semakin besar.

Diskusi2. Apakah ada perbedaan signal dari

pathogen dengan signal dari Jasmonic Acid? (Nurul)Ada. Serangan dari patogen yang akan memicu terbentuknya jasmonic acid. Jasmonic acid merupakan salah satu signaling bagi camalexin pada Arabidopsis.

Diskusi3. Bagaimana mekanisme pertahanan

jika terjadi serangan dari virus? Apakah sama dengan bakteri? (Darussalam)Mekanisme pertahanan terhadap virus berbeda dengan patogen lainnya. Virus mampu menduplikasi asam nukleat yang terdapat pada sel tumbuhan. Beberapa tumbuhan mampu membentuk vaksin untuk menangkal virus tersebut. Namun mekanisme pembentukan vaksin tersebut berbeda dengan biosintesis fitoaleksin.