Secondary metabolites jasmonic acid

Thirty-six plant species tested in cell suspension culture could be elicited by exogenously supplied methyl jasmonate to accumulate secondary metabolites by a factor of 9 to 30 over the control values. Induction by MJ was not specific to any one type of secondary metabolite but rather general to a wide spectrum of low molecular weight substances ranging from flavonoids, guaianolides and anthraquinones to various classes of alkaloids [96]. Endogenous jasmonic acid and its methyl ester (MJ) accumulate rapidly and transiently after treatment of plant cell suspension cultures of Rauvolfia canescens and Eschscholtzia califor-nica with a yeast elicitor [97]. 

To increase production and facilitate isolation, plant cells have been immobilised on various matrices such as polyurethane foam and calcium alginate gel beads,24 while elicitation (i.e. the induction of a defence response) is generally critical for the production of secondary metabolites. The rationale for the use of elicitors is that plants produce secondary metabolites as part of a defence response to stress, either biotic (pathogen infection) or abiotic (ultraviolet, toxic heavy metals and rare earth ions). Jasmonic acid plays a crucial role in plant stress responses and, along with fungal polysaccharides and heavy metals, is the most widely employed elicitor in plant tissue cultures.30... 

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. 

The jasmonoids are secondary metabolites of the fatty acid metabolism. Jasmonates play a role in signal transduction in plants, similar to that of the structurally related prostaglandins in mammals. 

Jasmonic acid (JA) and its methyl ester (MJA) are important members of the family of natural jasmonates. Exogenously adding MJA was shown to increase the production of secondary metabolites in a variety of plant species. Some synthetic elicitors have also been proven to be too. We describe a series of synthetic cell culture elicitors in Chapter 4, including MJA derivatives and benzothiadiazole (BTH) derivatives. Some of them display more potent activity in Taxus chinensis cell culture and Panax notoginseng cell culture than MJA, which reflects the full application of chemical bioengineering in plant cell culture. 

The biocatalytic counterpart for the stereoselective reductirai of alkenes is catalyzed by flavin-dependent ene-reductases, " EC 1.3.1.31], which are members of the old yellow enzyme family (OYE, Scheme 2.134) [968,969], first described in the 1930s [970]. These enzymes are widely distributed in microorganisms and in plants. Some of them occur in well-defined pathways, e.g., in the biosynthesis of fatty acids and secondary metabolites, such as morphine [971] and jasmonic acid [972]. Others are involved in the detoxification of xenobiotics [973], such as nitro esters [974] and nitro-aromatics [975] like trinitrotoluene (TNT) [976]. 

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