Molecular Characterization Of Bursicon Gene From The Small Brown Planthopper (Laodelphax Striatellus) And The Brown Planthopper(Nilaparvata Lusens)(Hemiptera: Delphacidae)

Bursicon is peptide neuropeptide hormone, which was first discovered inCalliphora erythocephala in1985. Bursicon triggers cuticle sclerotization,melanization (tanning) and wing expansion. To study the function of bursicon in thesmall brown planthopper (SBPH, Laodelphax striatellus) and the brown planthopper(BPH, Nilaparvata lugens), we first cloned the partial sequences of SBPH and BPHby PCR with the degenerated oligonucleotide primers, based on amino acid sequencesfrom other insects, and then cloned the5’ and3’ cDNA ends of bursicon by RapidAmplification of cDNA Ends (RACE). After that, we studied the expression ofbursicon gene in L. striatellus by real-time quantitative PCR (qRT-PCR) and thebursicon αlpha’s functions in N. lugens by using RNAi Technology. The results arereported as below:(1) The full-length sequences of bursicon αlpha (burs) and bursicon beta orpartner of burs (pburs) from SBPH were amplified by RT-PCR (reverse transcriptionPCR) and RACE, and were designated as Lsburs and Lspburs, respectively. Theproducts are1,126bp and761bp in length for Lsburs and Lspburs, respectively.Lsburs, which includes a5’ untranslated region (5’-UTR) of142bp, a3’-UTR of501bp with a canonical polyadenylation signal sequence AATAAA, a poly (A) tail,contains a483bp open reading frame (ORF) encoding a protein with160amino acidresidues, and it has two N-myristoylation sites, three casein kinase II phosphorylationsites and two protein kinase C phosphorylation sites. Lspburs, which included a short5’-UTR of66bp, a much longer3’-UTR of278bp with a canonical polyadenylationsignal sequence AATAAA, a poly (A) tail, contains a417bp ORF encoding a proteinwith138amino acid residues, and it has two N-myristoylation sites, three caseinkinase II phosphorylation sites and one tyrosine kinase phosphorylation site.Real-time quantitative PCR results showed that the transcripts of Lsburs and Lspburswere detectable in all the nymphal stages of L. striatellus, increased with the nymphal stages, reached the highest level in the emerging period, and then decreased afteradult eclosion. The results suggest that bursicon closely relates to cuticlesclerotization in L. striatellus after molting.(2) The full-length sequences of burs and pburs from BPH were amplified byRT-PCR and RACE, and were designated as Nlburs and Nlpburs, respectively. Theproducts are923bp and703bp in length for Nlburs and Nlpburs, respectively. Nlburs,which includes a short5’-UTR of149bp, a much longer3’-UTR of300bp with acanonical polyadenylation signal sequence AATAAA, a poly (A) tail, contains a474bp open reading frame (ORF) encoding a protein with157amino acid residues,and it has one N-myristoylation sites, three casein kinase II phosphorylation sites andtwo protein kinase C phosphorylation sites. Nlpburs, which included a short5’-UTRof73bp, a much longer3’-UTR of213bp with a poly (A) tail, but no canonicalpolyadenylation signal sequence, contains a417bp ORF encoding a protein with138amino acid residues, and it has one N-myristoylation sites, one tyrosine kinasephosphorylation site, three casein kinase II phosphorylation sites and one proteinkinase C phosphorylation sites. Phylogenetic Tree analysis showed that Bursiconfrom N. lugens are most closely related to L. striatellus. The result of RNAinterference (RNAi) displays: Nlburs silence can prolong the tanning of male N.lugens but not in females.