Defensive Responses of Tea Plants (Camellia sinensis) Against Tea Green Leafhopper Attack: A Multi-Omics Study

Xiaoman Zhao; Si Chen; Shanshan Wang; Wenna Shan; Xiaxia Wang; Yuzhen Lin; Feng Su; Zhenbiao Yang; Xiaomin Yu

doi:10.3389/fpls.2019.01705

Defensive Responses of Tea Plants (Camellia sinensis) Against Tea Green Leafhopper Attack: A Multi-Omics Study

Front Plant Sci. 2020 Jan 17:10:1705. doi: 10.3389/fpls.2019.01705. eCollection 2019.

Authors

Xiaoman Zhao^{1

2}, Si Chen^{1

2}, Shanshan Wang², Wenna Shan^{1

2}, Xiaxia Wang², Yuzhen Lin², Feng Su³, Zhenbiao Yang^{2

4}, Xiaomin Yu²

Affiliations

¹ College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou, China.
² FAFU-UCR Joint Center for Horticultural Biology and Metabolomics, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, Fuzhou, China.
³ Fujian Farming Technology Extension Center, Fuzhou, China.
⁴ Center for Plant Cell Biology, Department of Botany and Plant Sciences, Institute for Integrative Genome Biology, University of California, Riverside, Riverside, CA, United States.

Abstract

Tea green leafhopper [Empoasca (Matsumurasca) onukii Matsuda] is one of the most devastating pests of tea plants (Camellia sinensis), greatly impacting tea yield and quality. A thorough understanding of the interactions between the tea green leafhopper and the tea plant would facilitate a better pest management. To gain more insights into the molecular and biochemical mechanisms behind their interactions, a combined analysis of the global transcriptome and metabolome reconfiguration of the tea plant challenged with tea green leafhoppers was performed for the first time, complemented with phytohormone analysis. Non-targeted metabolomics analysis by ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-QTOF MS), together with quantifications by ultra-performance liquid chromatography triple quadrupole mass spectrometry (UPLC-QqQ MS), revealed a marked accumulation of various flavonoid compounds and glycosidically bound volatiles but a great reduction in the level of amino acids and glutathione upon leaf herbivory. RNA-Seq data analysis showed a clear modulation of processes related to plant defense. Genes pertaining to the biosynthesis of phenylpropanoids and flavonoids, plant-pathogen interactions, and the biosynthesis of cuticle wax were significantly up-regulated. In particular, the transcript level for a CER1 homolog involved in cuticular wax alkane formation was most drastically elevated and an increase in C29 alkane levels in tea leaf waxes was observed. The tea green leafhopper attack triggered a significant increase in salicylic acid (SA) and a minor increase in jasmonic acid (JA) in infested tea leaves. Moreover, transcription factors (TFs) constitute a large portion of differentially expressed genes, with several TFs families likely involved in SA and JA signaling being significantly induced by tea green leafhopper feeding. This study presents a valuable resource for uncovering insect-induced genes and metabolites, which can potentially be used to enhance insect resistance in tea plants.

Keywords: RNA-Seq; defense response; hormone signaling; metabolomics; plant-herbivore interaction; tea green leafhopper.