Silencing a sugar transporter gene reduces growth and fecundity in the brown planthopper, Nilaparvata lugens (Stål) (Hemiptera: Delphacidae).

Lin-Quan Ge,Yi-Ping Jiang,Qi-Sheng Song,Xiu-Li Lu,David Stanley,Jin-Cai Wu,Guo-Qing Yang,Ting Xia,Peng Kuai

doi:10.1038/srep12194

Abstract

The brown planthopper (BPH), Nilaparvata lugens, sugar transporter gene 6 (Nlst6) is a facilitative glucose/fructose transporter (often called a passive carrier) expressed in midgut that mediates sugar transport from the midgut lumen to hemolymph. The influence of down regulating expression of sugar transporter genes on insect growth, development, and fecundity is unknown. Nonetheless, it is reasonable to suspect that transporter-mediated uptake of dietary sugar is essential to the biology of phloem-feeding insects. Based on this reasoning, we posed the hypothesis that silencing, or reducing expression, of a BPH sugar transporter gene would be deleterious to the insects. To test our hypothesis, we examined the effects of Nlst6 knockdown on BPH biology. Reducing expression of Nlst6 led to profound effects on BPHs. It significantly prolonged the pre-oviposition period, shortened the oviposition period, decreased the number of eggs deposited and reduced body weight, compared to controls. Nlst6 knockdown also significantly decreased fat body and ovarian (particularly vitellogenin) protein content as well as vitellogenin gene expression. Experimental BPHs accumulated less fat body glucose compared to controls. We infer that Nlst6 acts in BPH growth and fecundity, and has potential as a novel target gene for control of phloem-feeding pest insects.

Highlights

The brown planthopper (BPH), Nilaparvata lugens, sugar transporter gene 6 (Nlst6) is a facilitative glucose/fructose transporter expressed in midgut that mediates sugar transport from the midgut lumen to hemolymph
The brown planthopper (BPH), Nilaparvata lugens, is the most serious insect rice pest throughout Asia, with outbreaks increasing in intensity[1,2]
Sucrose cannot be transported directly across the hemipteran gut epithelium. It is hydrolyzed into two monosaccharides, glucose and fructose, in the BPH midgut for transport into hemolymph circulation[8]

Summary

Introduction

The brown planthopper (BPH), Nilaparvata lugens, sugar transporter gene 6 (Nlst6) is a facilitative glucose/fructose transporter (often called a passive carrier) expressed in midgut that mediates sugar transport from the midgut lumen to hemolymph. It is reasonable to suspect that transporter-mediated uptake of dietary sugar is essential to the biology of phloem-feeding insects Based on this reasoning, we posed the hypothesis that silencing, or reducing expression, of a BPH sugar transporter gene would be deleterious to the insects. We presume sugar transporters act in multiple actions in membrane transport and energy acquisition The genes encoding these transporters may serve as potential targets for RNAi based control of insect pests in transgenic plants. We posed this idea as the hypothesis that silencing these genes will lethally reduce BPH fitness in agroecosystems. We report on the outcomes of experiments designed to test our hypothesis

Methods

Results

Conclusion