Molecular response of gall induction by aphid Schlechtendalia chinensis (Bell) attack on Rhus chinensis Mill

Haiying Wang,Kai Cui,Shuxia Shao,Juan Liu,Hang Chen,Chao Wang,Haixia Wu,Zixiang Yang,Qin Lu,Kirst King-Jones,Xiaoming Chen

doi:10.1080/17429145.2017.1392627

Abstract

ABSTRACTHorned gall is named after its shape of irregular diamond, and is induced by the fluid-feeding aphid Schlechtendalia chinensis (Bell) attacks on the leaflets that are located in the branchlets of Rhus chinensis Mill., which is enriched in gallotannin and can be widely used in medicine and the food industry. To explain the molecular mechanism of gall development, we performed transcriptome analysis by Illumina deep sequencing and digital gene expression of four tissues, including galls, leaves that grew on the same branch as the gall taken (GL), leaves from a branch without any gall (LW), and leaves from a tree without any gall (CL). Differentially expressed genes abundantly enriched in the biosynthesis of secondary metabolites, plant–aphid interactions, and plant hormone signal transduction were highly expressed in galls compared with GL and LW. Phytohormone signal transduction, dominated by IAA and ABA, coordinates primary and secondary metabolism and thus induces gall induction and development after attack by aphids. This study provides a theoretical basis for the genetic improvement and processing of gallnut resources.

Highlights

Rhus (Anacardiaceae) contains more than 250 species found in temperate and tropical regions worldwide that are characterized by the presence of several compound groups, including tannins, flavonoids, triterpenoids, phenolics, and aromatic alkanes (Djakpo and Yao 2010)
The extract of galls induced by infection with Schlechtendalia chinensis (Bell) is known to be effective in bacterial control since galls are rich in gallotannin (50–70%) and phenolic compounds, such as gallic acid (Djakpo and Yao 2010)
To facilitate access to the R. chinensis transcriptome data, raw paired-end sequence data in FASTQ format were deposited in the NCBI Sequence Read Archive (SRA) database with the accession number SRA302347

Summary

Introduction

Rhus (Anacardiaceae) contains more than 250 species found in temperate and tropical regions worldwide that are characterized by the presence of several compound groups, including tannins, flavonoids, triterpenoids, phenolics, and aromatic alkanes (Djakpo and Yao 2010). The extract of galls induced by infection with Schlechtendalia chinensis (Bell) is known to be effective in bacterial control since galls are rich in gallotannin (50–70%) and phenolic compounds, such as gallic acid (Djakpo and Yao 2010). Species-specific gall is abnormal plant tissue, and is generally induced by insect parasitism, which evolves into a relationship between the insect and the host plant akin to mutualism (Cooper and Rieske 2010; Tokuda 2012; Nabity et al 2013). To disclose the adaptive significance of galls, several hypotheses have been proposed, including defense from natural enemies, protection from the external environment, expansion of the surface area available for consumption, and enhancement of the nutritional quality of plant tissue (Price et al 1987). RNA-seq is a powerful and efficient tool to identify differentially expressed genes (DEGs) at the whole-genome level and is especially effective for screening the transcriptome of non-sequenced species (Wang et al 2009)

Methods

Results

Conclusion