Comparison of Transcriptome Responses between Sogatella furcifera Females That Acquired Southern Rice Black-Streaked Dwarf Virus and Not.

Dandan Liu,Maolin Hou,Zhengxi Li

doi:10.3390/insects13020182

Abstract

Simple SummaryThe southern rice black-streaked dwarf virus (SRBSDV) is transmitted horizontally by the planthopper, Sogatella furcifera. During feeding on virus-infected plants, S. furcifera may acquire or fail to acquire SRBSDV. In this study, the responses were compared among the S. furcifera successfully acquiring the virus, those failing to acquire the virus, and those not exposed to SRBSDV (the control). A total of 1043 and 2932 differentially expressed genes (DEGs) were obtained in S. furcifera females that acquired SRBSDV and that failed to, in comparison with the control, respectively. Functionally, these DEGs are primarily involved in diverse signaling pathways related to primary metabolism and innate immunity, such as apoptosis. Additional bioassays confirmed the activation of apoptosis in S. furcifera by SRBSDV exposure. Interestingly, we also found that six female-specific genes were also upregulated in S. furcifera females exposed to SRBSDV. Our results further the understanding of the interactions between the vector S. furcifera females and SRBSDV at the molecular level.The southern rice black-streaked dwarf virus (SRBSDV) is transmitted horizontally by Sogatella furcifera in a persistent, propagative manner. Exposure of S. furcifera females to SRBSDV-infected rice plants may trigger transcriptomic changes in the insects, the transcriptomes of females that acquired SRBSDV and those that failed to, as well as females fed on healthy rice plants as control, were sequenced and compared. Nine transcriptomic libraries were constructed, from which a total of 53,084 genes were assembled. Among the genes, 1043 and 2932 were differentially expressed genes (DEGs) in S. furcifera females that acquired SRBSDV and that failed to, in comparison with the control, respectively. Functional enrichment analysis showed that DEGs identified in S. furcifera females exposed to SRBSDV are primarily involved in diverse signaling pathways related to primary metabolism and innate immunity. The DEGs in the S. furcifera females that failed to acquire the virus significantly outnumbered that in the insects that acquired the virus, and the virus exposure activated the humoral and cellular immune responses of the vectors, especially the apoptosis. The key gene in apoptosis encoding caspase 1 was upregulated by SRBSDV exposure, especially in S. furcifera females that failed to acquire the virus. Analysis of caspase 1 activity validated that SRBSDV exposure induced caspase 1 accumulation. Surprisingly, the expression of six female-specific genes was also upregulated by SRBSDV exposure, which was confirmed by RT-qPCR analysis. This study provides evidence to explain the differential virus acquisition at the transcriptome level.

Highlights

The white-backed planthopper, Sogatella furcifera Horváth (Hemiptera: Delphacidae), is a dimorphic and migratory insect pest
The 53,084 genes ranging from 201 bp to 11,242 bp with a median length of 395 bp were assembled (Table 2), of which 9650 (18.18%) and 17,102 (32.22%) genes had homologous sequences in the SwissProt and NR protein databases, respectively, and 10,802 (20.35%), 10,059 (18.95%), 13,198 (24.86%), and 10,543 (19.86%) genes were classified by GO, KEGG, eggNOG, and Protein family (Pfam) databases, respectively (Table 3)
Southern rice black-streaked dwarf virus (SRBSDV) (Sf–V) (Figure 2), and 2932 differentially expressed genes (DEGs) in insects that failed to acquire virus (Sf–NV). Functional analysis of these DEGs showed that primary metabolism was modulated, which was consistent with the transcriptomic analysis of S. furcifera males or mixed populations infected with SRBSDV [17,18]

Summary

Introduction

The white-backed planthopper, Sogatella furcifera Horváth (Hemiptera: Delphacidae), is a dimorphic and migratory insect pest. It causes tremendous loss in rice production by sucking phloem sap from leaf sheath and transmitting the rice virus [1,2,3]. Southern rice black-streaked dwarf virus (SRBSDV) is a devastating virus transmitted exclusively by. In the case of SRBSDV, virus acquisition is higher at 32 ◦ C and 27 ◦ C than at 22 ◦ C, from tillering stage plants than from three-leaf stage and booting stage plants, and by third instars than by fifth instars [8]. The infection of SRBSDV induces physiological and/or behavioral changes in

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