Evolution and functional analysis of odorant-binding proteins in three rice planthoppers: Nilaparvata lugens, Sogatella furcifera, and Laodelphax striatellus.
BACKGROUND
The white-backed planthopper (WBPH) Sogatella furcifera, the brown planthopper (BPH) Nilaparvata lugens, and the small brown planthopper (SBPH) Laodelphax striatellus are three notorious rice pests that cause annual losses in rice yield through sap-sucking and virus transmission. Odorant-binding proteins (OBPs) are crucial olfactory genes involved in host-seeking behavior.


RESULTS
We discovered the presence of 12, 12, and 16 OBPs in WBPH, BPH, and SBPH, respectively, including two novel OBPs in BPH and seven novel OBPs in SBPH. Phylogenetic analysis indicated that most of these OBPs have homologous genes, and one group (SfurOBP11, NlugOBP8, and LstrOBP2) show a slower evolution rate and are more conserved. Further, in vitro binding studies demonstrated that the three OBPs have similar binding affinities for some rice plant volatiles. Finally, RNA interference (RNAi) successfully inhibited the mRNA expression of the three OBPs, and in vivo behavioral tests showed that the OBP-deficient rice planthoppers were partly anosmic and lost some of their ability to locate rice plants.


CONCLUSION
These results demonstrate the crucial role of the rice planthopper OBP genes in seeking rice plants. This information complements the current genetic resources for the development of RNAi-based transgenic rice and other pest management technologies. © 2018 Society of Chemical Industry.
['He|Peng|P|https://orcid.org/0000-0003-2934-0044', 'Chen|Guang-Lei|GL|', 'Li|Shuo|S|https://orcid.org/0000-0002-0811-5166', 'Wang|Jun|J|', 'Ma|Yun-Feng|YF|', 'Pan|Yu-Feng|YF|', 'He|Ming|M|']
D000595:Amino Acid Sequence D000818:Animals D019143:Evolution, Molecular D006430:Hemiptera D019476:Insect Proteins D008958:Models, Molecular D010802:Phylogeny D011487:Protein Conformation D018035:Receptors, Odorant D013045:Species Specificity
odorant-binding protein rice planthoppers host-seeking behavior RNAi binding properties olfaction