A Disease Resistance Elicitor Laminarin Enhances Tea Defense against a Piercing Herbivore Empoasca (Matsumurasca) onukii Matsuda

Zhaojun Xin,Lingang Ge,Zongmao Chen,Xiaoming Cai,Shenglong Chen,Zhaoqun Li,Lei Bian,Zongxiu Luo

doi:10.1038/s41598-018-37424-7

Zhaojun Xin, Lingang Ge + Show 6 more

Open Access

https://doi.org/10.1038/s41598-018-37424-7

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Abstract

The tea plant (Camellia sinensis) suffers heavily from a harmful piercing pest, the tea green leafhopper (TLH) Empoasca (Matsumurasca) onukii Matsuda. In the present study, we studied the effect of an efficient elicitor of plant disease resistance, the β-1,3-glucan laminarin, on the induced defense against TLH in tea plants. Defense responses elicited by laminarin in tea include the activation of mitogen-activated protein kinases and WRKY, the burst of H2O2, salicylic acid, and abscisic acid, and the accumulation of direct-defense chemicals (including chitinase, phenylalanine ammonia lyase, callose, polyphenol oxidase, and flavonol synthase), as well as the production of volatile compounds. The laminarin-treated tea plants reduced the performance of TLH and enhanced the attractiveness to the egg parasitoid wasp of TLH, Stethynium empoascae Subba Rao. In the field experiment, laminarin application effectively reduced the number of TLH by attracting parasitoids. These results suggest that laminarin can induce protection against TLH by regulating signaling pathways in tea plant. Our study also proposes an environment friendly strategy for the integrated management of an economically important piercing pest.

Highlights

Plants use different defense pathways to respond to insects with different feeding modes[7]
We investigated whether treatment with laminarin alters the expression of CsMAPK and CsWRKY329 in C. sinensis
We provided evidences supporting foliar application a plant disease resistance elicitor, laminarin, can supply tea plants protection against the sap-sucking herbivore tea green leafhopper (TLH) in laboratory and field, and the efficacy of laminarin relied on the activation of tea induced defense responses

Summary

Introduction

Plants use different defense pathways to respond to insects with different feeding modes[7]. To date, accumulating evidences have indicated that plant defense mechanisms can be activated by various chemical elicitor types, including (i) naturally occurring phytohormones, such as JA, SA, ABA, and ET1,11,12; (ii) the other elicitors exist in plants, for example, green leaf volatiles or terpene compounds[6]; (iii) the synthetic elicitors not exist in plants, e.g., 3,5-dichloroanthranilic acid and 2,4-dichlorophenoxyacetic acid (2,4-D)[13,14] These chemical elicitors are not directly toxic to pests but capable of inducing defense-related signaling pathways in www.nature.com/scientificreports/. The tea green leafhopper (TLH), Empoasca (Matsumurasca) onukii Matsuda (Hemiptera: Cicadellidae), an extremely harmful piercing pest with ten generations per year, is by far the most serious threat to tea plant cultivation[18]. Exploiting chemical elicitors is an efficient strategy to defend tea plants against TLH16,20

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