Jasmonic Acid (JA) Acts as a Signal Molecule in LaCl3-Induced Baicalin Synthesis in Scutellaria baicalensis Seedlings

Jie Zhou,Luqi Huang,Lanping Guo,Xuan Li,Lei Fang

doi:10.1007/s12011-012-9379-8

Abstract

Rare earth elements (REEs) have been widely used to increase accumulation of biomass and secondary metabolites in medicinal plants in China. However, very few studies have investigated how REEs mediate secondary metabolism synthesis in medicinal plants. Lanthanum (La), an important REE, is known to improve the accumulation of secondary metabolites in medicinal plants and is widely distributed in China. However, few studies have evaluated the signal transduction leading to La-induced secondary metabolism in medicinal plants. In this study, LaCl3 treatment-induced multiple responses in Scutellaria baicalensis seedlings, including the rapid generation of jasmonic acid (JA), sequentially followed by the enhancement of baicalin production. Direct application of JA also promoted the synthesis of baicalin in the absence of LaCl3. LaCl3-induced baicalin synthesis was blocked by two different JA synthesis inhibitors. Our results showed that JA acts as a signal component within the signaling system leading to La-induced baicalin synthesis in S. baicalensis seedlings.

Highlights

Traditional Chinese medicine (TCM) plays an important role in maintaining people’s health [1]
After 2 weeks of growth, plants were treated with a solution of either (1) LaCl3 (100 mg/L), (2) jasmonic acid methyl ester (JAMe; 10−5 mol/L), (3) LaCl3 and its synthesis inhibitor salicylhydroxamic acid (SHAM; 100 μmol/L), (4) LaCl3 and its synthesis inhibitor n-propyl gallate (PrGall) (100 μmol/L), and (5) JAMe and SHAM
The La-induced baicalin synthesis was blocked by JA synthesis inhibitors, which strongly suggested that JA was involved in the LaCl3 signal transduction that induced baicalin synthesis, in other words, baicalin synthesis was induced at least partially via a JA signal transduction pathway

Summary

Introduction

Traditional Chinese medicine (TCM) plays an important role in maintaining people’s health [1]. During the last two decades, the use of herbal medicines has expanded globally and gained considerable attention because of their low toxicity and good therapeutic performance [2]. Scutellaria baicalensis (referred to in TCM as “huang qin”) is one of the 50 fundamental herbs used in TCM. Baicalin is the most abundant active component in huang qin and is an important secondary metabolite in S. baicalensis induced by exogenous stress. It has anti-inflammatory, anti-HIV, anti-tumor and anti-severe acute respiratory syndrome coronavirus effects [3]. The everincreasing demand for huang qin has stimulated the improvement of cultivated practices of S. baicalensis

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Results

Conclusion