Conifer cell cultures as a tool for studying the induction of terpenoid defense compounds

ABSTRACT

Conifer trees often increase their production of terpene resins after attack by herbivores or pathogens, a defense response that may be critical in their survival. Yet it has proved difficult to study such terpene induction under laboratory conditions because of the need for mature trees and specific organs and cells at the proper stage of development. Here we explore the potential of Norway spruce (Picea abies) cell cultures to be a convenient system for studying terpene induction in this species. We demonstrated that P. abies cell suspension cultures accumulated a mixture of monoterpenes (but not of sesquiterpenes or diterpenes), similar to that found in intact trees, but at level of only 0.5–2.5% those in intact trees. However, treatment with the hormone methyl jasmonate and the fungal elicitor chitosan increased monoterpene accumulation 2–4-fold. Based on in vitro assays of terpene synthase activity, this increase was driven by an increased rate of biosynthesis, and was likely not due to pH changes caused by hormone or fungal elicitor treatment. Since these defense responses of P. abies cell cultures are typical of the response of intact spruce needles and bark, such cultures may have promise as a laboratory system for studying the induction of terpene resin defenses.

KEYWORDS:

• Elicitor
• induction
• jasmonate
• monoterpenes
• spruce

Acknowledgments

We thank the Max Planck Society for support of this research project.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Author Contributions

Gazmend Zeneli designed the research, performed the experiments and was responsible for data acquisition and analysis. He wrote the first draft of the manuscript and all of the other authors helped with the revision. Trevor M. Fenning established the spruce cell culture line. Jonathan Gershenzon helped design and supervised the research.

Data availability statement

Data sharing is not applicable to this article

Additional information

Funding

This research project was supported by the Max Planck Society