Knockdown of an ABC transporter leads to bright red eyes in the brown planthopper, Nilaparvata lugens (Stal) (Hemiptera: Delphacidae)

Compound eye color is an important biological character of insects, which is determined by the nature of eye pigments. Ommochrome is the solely source of eye color for some insects, while pteridines is also needed for the other insect species. However, little is known about the eye pigment composition for any planthopper. Scarlet is an ABC (ATP-binding cassette) transporter protein, which functions as the transmembrane transporter for ommochrome precursor. The failure of Scarlet function can cause bright red or white eyes in different species, which depending on the nature of eye pigments. Here, we identified a scarlet ortholog gene (Nlst) from the brown planthopper (BPH), Nilaparvata lugens, which is a destructive insect pest of rice. Nlst is the first characterized eye pigment transporter gene from Hemipteran. NlSt, the protein deduced from Nlst, has an open reading frame (ORF) of 629 amino acids with the two sequence logos for eye pigment transporters. Expression profile revealed that Nlst expressed at all development stages and had the highest transcript level in head. Knockdown the Nlst transcript, the wild-type eye color partially changed to bright red, while not to white. Meantime, the ommochrome level in heads reduced to 73.4%. These results suggested that the eye coloration of BPH needs both ommochrome and pteridines pigments. Because nymphal RNAi with Nlst leading to a clearly distinguished phenotype from the control individuals, Nlst maybe a suitable genetic marker to exploit embryonic RNAi technique in this insect pest. (C) 2017 Published by Elsevier B.V. on behalf of Korean Society of Applied Entomology, Taiwan Entomological Society and Malaysian Plant Protection Society.