Methyl jasmonate‐induced nicotine production in Nicotiana attenuata: inducing defenses in the field without wounding

Abstract

The functional significance of herbivore-induced plant traits known to directly or indirectly influence herbivore performance remains largely untested under field conditions due to the difficulty of uncoupling the response to herbivory from the act of herbivory. The signals that activate many of the induced responses in plants are endogenously produced in response to wounding, unlike many of the predator-induced responses found in aquatic invertebrates (which are activated by exogenous cues derived from predators). Jasmonates, endogenously-produced damage signals, activate diverse wound-induced responses in plants including induced nicotine production in Nicotiana sylvestris. The results presented here are from two experiments which illustrate the use ofjasmonates to uncouple induced nicotine production in Nicotiana attenuata (Torrey ex. Watson) from wounding. The exogenous addition of methyl j asmonate (MJ) in small quantities (11/~g for a 1.4 g dry mass plant) to roots of hydroponicallygrown plants induces de novo nicotine synthesis and increases whole-plant nicotine concentrations just as wounding does. The MJ-induced changes were proportional to the quantity of MJ given. Moreover, the effects of MJ were additive to the effects of damage. Applications of MJ to shoots were less effective. Root treatments also worked with plants growing in a field plot. The application of MJ represents a promising tool for examining the functional significance of induced nicotine responses in plants growing in their native environments.

Jasmonic acid treatment and mammalian herbivory differentially affect chemical defenses and growth of wild mustard ( Brassica kaber )

“…JA, a fatty acid derivative, is found in many plants and can elicit numerous chemical and physiological responses through the regulation of an octadecanoidbased signaling pathway (Karban & Baldwin 1997). In many plant species, wounding increases endogenous levels of JA, and exogenous JA stimulates the expression of defensive chemicals and resistance in a pattern similar to wounding or insect feeding (Creelman et al 1992;Bodnaryk and Rymerson 1994;Baldwin 1996;Thaler et al 1996). Although less studied than in the Solanaceae, the wound-induced expression of trypsin inhibitors (one type of PI) in the Brassicaceae is consistent with regulation by JA (Cipollini & Bergelson 2000.…”

Promotion of nicotine biosynthesis in transgenic tobacco by overexpressing allene oxide cyclase from Hyoscyamus niger

“…Jasmonates are proved to be part of a signaltransduction pathway which dramatically increases nicotine pools in response to wounding of the leaves in tobacco (Baldwin et al 1994Ohnmeiss et al 1997); and without wounding, exogenous methyl-jasmonate induces the similar eVects as well, avoiding the cost of damnifying the plants (Baldwin et al 1994;Baldwin 1996). In this report, overexpression of heterologous jasmonate biosynthetic pathway gene for increased nicotine yield was investigated.…”

Tobacco mosaic virus inoculation inhibits wound-induced jasmonic acid-mediated responses within but not between plants

“…After leaf wounding, JA concentrations in wounded leaves increase rapidly and transiently, with pools waxing and waning within minutes Blechert et al 1995;Baldwin et al 1997;Creelman and Mullet 1997). This JA burst precedes the activation of several defense-related genes (Creelman et al 1992;Doares et al 1995b) and the accumulation of plant defense compounds, including proteins (Doares et al 1995b;Howe et al 1996), alkaloids (Dittrich and Kutchan 1991;Baldwin et al , 1997Baldwin 1996), avonoids (Gundlach et al 1992Mueller et al 1993), and phenolics (Mizukami et al 1993). In comparison, SA displays a slower, more attenuated response to tobacco mosaic virus (TMV) inoculation, with systemic increases occurring several days after inoculation and lasting for several weeks (Raskin 1992).…”

“…The increase in JA in wounded leaves and its apparent transport to the roots, where nicotine is synthesized, is necessary and sucient to activate de-novo nicotine production in this species Zhang and Baldwin 1997). Jasmonic acid and its methyl ester, MJ, increase nicotine production in other Nicotiana species (Baldwin and Ohnmeiss 1993;Baldwin 1996). By increasing the endogenous SA levels and releasing MeSA into the air, a virus-inoculated tobacco plant may not only inhibit its own abilities to synthesize JA and accumulate nicotine in response to wounding or herbivore attack, but may also compromise the defensive ability of nearby, uninoculated plants.…”