Natural chemical elicitors

3 Natural Chemical Elicitors 6.2.3.1 Inorganic Metal Salts 

Inorganic metal salts can induce secondary metabolism in plant cell cultures, such as Cu and Ag. Cu elicited phytoalexin production in rice plants/ Adding AgNOs induced taxol biosynthesis/ Rare earth metal salts, such as (NH4)2Ce(N03)6, can also increase the accumulation of paclitaxel in Taxus cells/ Ginsenoside biosynthesis was elicited in cell cultures of Panax ginseng by vanadate/ The metabolic action of inorganic metal salts inducing the accumulation of secondary metabolites may be similar to other natural chemical elicitors/  

Salicylic acid (SA) is a phenolic compound biosynthesized through the phenylpropanoid pathway. SA has emerged as a key signaling component 

---

Chemicals heavy metals, nature chemical JA or SA, synthetic elicitors... 

We can distinguish between secondary metabolites that are already present prior to an attack or wounding, so-called constitutive compounds, and others that are induced by these processes and made de novo. Inducing agents, which have been termed elicitors by phytopathologists, can be cell wall fragments of microbes, the plant itself, or many other chemical constituents (4,17,22-24). The induced compounds are called phytoalexins, which is merely a functional term, since these compounds often do not differ in structure from constitutive natural products. In another way this term is misleading, since it implies that the induced compound is only active in plant-microbe interactions, whereas in reality it often has multiple functions that include antimicrobial and antiherbivoral properties (see below). 

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. 

This classification, established on the basis of observations at the macroscopic scale, only takes into account the phenomena of chemical mediation at the molecular scale and the biochemical mechanisms involved. For example, how to classify compounds as elicitors which will activate the natural defense mechanisms of plants The knowledge acquired in recent years in chemical ecology, by highlighting species-specific relations, the structural characterization and mode of action (attractants, repellents, elicitors, stimulants, etc.) of chemical mediators, have lead researchers involved in bio-control to propose a classification based on the mode of action of the chemical mediators ... 

---