Genome-Wide Identification and Characterization of Amino Acid Polyamine Organocation Transporter Family Genes Reveal Their Role in Fecundity Regulation in a Brown Planthopper Species (Nilaparvata lugens).

Lei Yue,Mingzhao Zhong,Kai Liu,Luyao Zhao,Ziying Guan,Rui Pang

doi:10.3389/fphys.2021.708639

Abstract

The brown planthopper (BPH), Nilaparvata lugens Stål (Hemiptera:Delphacidae), is one of the most destructive pests of rice worldwide. As a sap-feeding insect, the BPH is incapable of synthesizing several amino acids which are essential for normal growth and development. Therefore, the insects have to acquire these amino acids from dietary sources or their endosymbionts, in which amino acid transporters (AATs) play a crucial role by enabling the movement of amino acids into and out of insect cells. In this study, a common amino acid transporter gene family of amino acid/polyamine/organocation (APC) was identified in BPHs and analyzed. Based on a homology search and conserved functional domain recognition, 20 putative APC transporters were identified in the BPH genome. Molecular trait analysis showed that the verified BPH APC family members were highly variable in protein features, conserved motif distribution patterns, and exon/intron organization. Phylogenetic analysis of five hemipteran species revealed an evolutionary pattern of interfamily conservation and lineage-specific expansion of this gene family. Moreover, stage- and tissue-specific expression analysis revealed diverse expression patterns in the 20 BPH APC transporter genes. Lastly, a potential BPH fecundity regulatory gene of NlAPC09 was identified and shown to participate in the fecundity regulation through the use of quantitative polymerase chain reaction (qPCR) and RNA inference experiments. Our results provide a basis for further functional investigations of APC transporters in BPH.

Highlights

As the key nutrients in animals, amino acid plays some irreplaceable roles in diverse biological processes, including energy regulating, protein synthesis, stress adaptation, nerve transmission, and cell development (Gordon, 1968; Wu, 2009; Wu et al, 2014)
The brown planthopper (BPH) population used in gene cloning of APC transporters and RNAi experiments was originally collected in the Guangdong Province of China in 2012, and the insects were reared on rice seedlings of the Huanghuazhan cultivar in a greenhouse maintained at 26 ± 2◦C, with a relative humidity (RH) of between 70 and 90%, and a photoperiod of 16 h:8 h
Twenty APC transporters with complete cDNA sequences were identified in the BPH genome and named NlAPC01 to NlAPC20 according to their position information on the chromosome (Table 1 and Supplementary Table 2)

Summary

Introduction

As the key nutrients in animals, amino acid plays some irreplaceable roles in diverse biological processes, including energy regulating, protein synthesis, stress adaptation, nerve transmission, and cell development (Gordon, 1968; Wu, 2009; Wu et al, 2014). Two major amino acid transporter families have been reported, which are the amino acid auxin permease (AAAP) family and the amino acid polyamine organocation (APC) family (Attardo et al, 2006; Price et al, 2011; Dahan et al, 2015). Both AATs family proteins showed great variations in length. Previous studies have revealed that AATs could function as symporter and antiporters to ensure the proper cross-membrane flux of solutes (Wolfersberger, 2000)

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