Effect of Seasonal Decrease in Temperature on the Content and Composition of Guayulins in Stems of Guayule (Parthenium argentatum, Gray).

Juana Rozalén,Horacio López-Córcoles,M. Mercedes García-Martínez,Manuel Carmona,Amaya Zalacain,Maria Engracia Carrión

doi:10.3390/plants10030537

Abstract

The guayulins are a family of sesquiterpene compounds that consist of an isoprenoid nucleus substituted either by trans-cinnamic or p-anisic acid, and are present only in the resinous fraction of the rubber plant guayule (Parthenium argentatum, Gray). While the natural role of the guayulins remains enigmatic, they may serve as a defense function against other plants or herbivores by virtue of the accumulation of cinnamic acid. Prior research has suggested seasonal variation in guayulin content, which has been shown to decrease as winter arrives in two different varieties. In the present study, the effect of guayulins has been evaluated in 13 different accessions cultivated under the same conditions during autumn. A general reduction in guayulin content was found in the stems from all varieties between the September and November harvest, which was accompanied by an increase in the resin content. With respect to individual guayulins, while guayulin A was the most prominent member during most of the year, guayulin C had more prominence when temperature started to decrease. In this seasonal period, the production of each member of the guayulin family in the leaves was very balanced.

Highlights

IntroductionPublisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.Licensee MDPI, Basel, Switzerland.The guayulin family of sesquiterpene secondary metabolites comprises four known members, guayulin A–D [1,2], several other members may exist [3,4]
Guayulins have been described in high concentration in the resin component of the rubber plant commonly known as guayule (Parthenium argentatum, Gray), a perennial shrub native to the Chihuauhan desert region of northern Mexico and Texas that does not produce the pseudoguaianolide sesquiterpene lactones found in almost all other species of the genus Parthenium [8]

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. The guayulin family of sesquiterpene secondary metabolites comprises four known members, guayulin A–D [1,2], several other members may exist [3,4]. Guayulin A was first isolated in 1911 and its structure was determined some years later [5,6]. Guayulins have been described in high concentration in the resin component of the rubber plant commonly known as guayule (Parthenium argentatum, Gray), a perennial shrub native to the Chihuauhan desert region of northern Mexico and Texas that does not produce the pseudoguaianolide sesquiterpene lactones found in almost all other species of the genus Parthenium [8]

Methods

Results

Conclusion