Pathways octadecanoid

LAUDERT, D., PFANNSCHMIDT, U., LOTTSPEICH, F HOLLANDER-CZYTKO, H., WEILER, E.W., Cloning, molecular and functional characterization of Arabidopsis thaliana allene oxide synthase (CYP74) the first enzyme for the octadecanoid pathway to jasmonates, Plant Mol. Biol., 1996,31,323-335. 

The alcohol moiety is produced in a different manner from that of the acid moiety. The alcohol moiety resembles the plant hormone jasmonic acid (JA) (26) generated from linolenoyl moiety of lipids via (13,S )-hydroperoxy-linolenic acid (22), (12.13,S )-epoxylinolenic acid (23), and 12-oxo-cis-10.15-phytodienoic acid (24) by the oxylipin or octadecanoid pathway (Fig. 3) [31]. In fact, 13C was incorporated at pyrethrolone (1) carbon positions that agreed with those predicted to be labeled when the alcohol moiety is produced via the pathway (Fig. 3) [30]. Figure 3 illustrates that m-jasmone (25) is hydroxylated to yield jasmololone (4), which is then dehydrogenated to yield pyrethrolone (5). However, it has not yet been determined if this is actually the case. 

Bouarab K, Adas F, Gaquerel E, Kloareg B, Salaun J-P, Potin P (2004) The innate immunity of a marine red alga involves oxylipins from both the eicosanoid and octadecanoid pathways. Plant Physiol 135 1838-1848... 

Orozco-Cardenas ML, Ryan CA (1999) Hydrogen peroxide is generated systemically in plant leaves by wounding and systemin via the octadecanoid pathway. Proc Natl Acad Sci USA 96 6553-6557... 

Muellet MJ, Brodschelm W, Spannagl E, Zenk MH, Signaling in the elicitation process is mediated through the octadecanoid pathway leading to jasmonic acid, Proc Natl Acad Sci 175/4 90 7490-7494, 1993. 

Conclusive held evidence has been obtained with the manipulation of odor emissions of free-standing plants. Thaler (1999), for example, observed an increase in parasitism of S. exigua larvae on tomato after the plants had been treated with JA. This treatment induces the octadecanoid pathway, which results in the production of various defense compounds, including volatiles. In an earlier study in a tobacco held, De Moraes et al. (1998) had already found that the specialist parasitoid... 

Orozco-Cardenas M, Ryan CA (1999) Hydrogen Peroxide is Generated Systematically in Plant Leaves by Wounding and Systemin Via the Octadecanoid Pathway. Proc Natl Acad Sci U S A 96 6553... 

MENKE, F.L., PARCHMANN, S., MUELLER, M.J., KUNE, J.W., MEMELINK, J., Involvement of the octadecanoid pathway and protein phosphoiylation in fungal elicitor-induced expression of terpenoid indole alkaloid biosynthetic genes in Catharanthus roseus. Plant Physiol., 1999,119, 1289-1296. 

JAs are derived from linolenic acid via an octadecanoid pathway consisting of several enzymatic steps (Figure 36). Multiple compartments in plant cells participate in JA synthesis. The early steps of this pathway occur in chloroplasts, where linolenic acid is converted to OPDA by means of the three enzymes lipoxygenase (LOX), allene oxide synthase (AOS), and allene oxide cyclase (AOC).867-869 Linolenic acid is oxygenated by 13-LOX producing a peroxidized fatty acid 13-hydroperoxylinolenic acid. The product is subsequently metabolized by AOS to an unstable compound allene oxide. Allene oxide is sequentially converted by AOC to produce OPDA. An alternative pathway from another trienoic fatty acid, hexadecatrienoic acid (16 3), is present in chloroplasts.870 In this pathway, dinor OPDA is produced instead of OPDA. OPDA and dinor OPDA are transported into the peroxisome. An ABC transporter involved in this transport was identified in... 

In plants, responses to many biotic and abiotic stresses are, at least in part, mediated by the jasmonate family, including jasmonate (JA) and its methyl ester MeJA, which are synthesized via the octadecanoid pathway, beginning with phospholipase A to release linolenic acid from chloroplast membrane [27,28]. They play a central role in regulating the biosynthesis of many secondary metabolites, and induction of plant secondary metabolite accumulation by the JA family is not limited to certain types of metabolites in most plants [29], as shown in Table 17.1. 

MILLER, B., MADILAO, L.L., RALPH, S., BOHLMANN, J., Insect-induced conifer defense. White pine weevil and methyl jasmonate induce traumatic resinosis, de novo formed volatile emissions, and accumulation of terpenoid synthase and octadecanoid pathway transcripts in Sitka spruce. Plant Physiol, 2005, 137, 369-382. 

The last point to discuss is biological activity in agriculture because chitosan has antivirus and antiphage activities [223], It inhibits the growth of bacteria and bacterial infection and stimulates the natural defences in plants. A mechanism was proposed through the octadecanoid pathway [224],... 

Doares, S.H., Syrovets, T, Weiler, E.W. and Ryan, C.A. (1995) Oligogalacturonides and chitosan activate plant defensive genes through the octadecanoid pathway. Proceedings of the National Academy of Sciences of the United States of America, 92, 4095-4098. 

Peebles CAM, Shanks JV, San K-Y (2009) The role of the octadecanoid pathway in the production of terpenoid indole alkaloids in Catharanthus roseus hairy roots under normal and UV-B stress conditions. Biotechnol Bioeng 103(6) 1248-1253... 

An important defence response is the induction of secondary metabolite accumulation, which depends on JAs as a regulatory signal. JAs are fatty acid derivatives which are synthesized via the octadecanoid pathway (Fig. 1). Most of the... 

Fig, 1 Schematic representation of the octadecanoid pathway leading to jasmonic acid biosynthesis. 12-OH-JA, 12-hydroxy-jasmonic acid AOC, allene oxide cyclase AOS, allene oxide synthase JA, jasmonic acid JARl, enzyme responsible for the conjugation of JA with isoleucine (JA-Ile) JMT, 5 -adenosyl-L-methionine jasmonic acid carboxyl methyl transferase LA, a-linolenic acid LOX, lipoxygenase MeJA, methyl jasmonate OPDA, 12-oxo-phytodienoic acid OPR3, OPDA reductaseS PL, phospholipase... 

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