Functions Of Nlmad In Wing Development And Wing Morph Differentiation Of Nilaparvata Lugens

As one of the main pests of rice,the brown planthopper(Nilaparvata lugens,BPH)had posed a serious threat to food production safety in our country.BPH has typical dimorphism.When the environmental condition(such as food)is poor,adults develop into a long-winged type,which is easy to migrate and transfer.When conditions become suitable,adults develop into a short-winged type,rapidly increasing their population.The study of the molecular mechanism of wing morphs differentiation of BPH is important work to reveal the disaster mechanism of BPH and formulate targeted green prevention and control strategies.The molecular mechanism of wing morphs differentiation of BPH has made great progress in recent years.There have been many reports on the regulation of wing morphs differentiation by wing morphs switching genes,wing development genes and mi RNA.Although great progress has been made in the molecular mechanism of wing morphs differentiation of BPH,there are still many scientific questions to be clarified.For example,mothers against dpp(mad)is a key downstream gene in the Dpp signaling pathway.At the same time,mad interacts with Fox O,Fox O is a key member of IIS control wing morphs.This suggests that mad may also play a key role in wing morphs differentiation of BPH,and is worth to be further studied.This study reveals the function of mad(Nlmad)and mad transcript variant X1(Nlmad X1)in wing morphs differentiation of BPH by means of RNA interference.The main results are as follows:1.The total length of Nlmad is 2382 bp,and the open reading frame(ORF)is 1368 bp,encoding 455 amino acids.The full length of Nlmad X1 is 3069 bp,in which the open reading frame(ORF)is 1419 bp,encodes 472 amino acids.The protein sequence alignment analysis showed that: Nlmad and Nlmad X1 of BPH are identified as transcription variants.The homology of MAD and MAD X1 proteins is as high as79.87%,and both has highly conserved MH1 and MH2 domains.But compared to MAD Linker region of MAD X1 has an extra DNA polymerase structure.In addition,MAD and MAD X1 include nuclear localization signal(NLS),nuclear export signal 1(NES1),nuclear export signal 2(NES2),DNA binding motif and SXS motif.However,MAD protein has one amino acid mutation in NES2 and one in SXS motif.Phylogenetic tree analysis showed that: The MAD X1 and MAD proteins of the three rice planthopper species are highly homologous.The amino acid sequence similarity between BPH MAD and grey planthopper MAD is 98.28%.The amino acid sequence similarity of BPH MAD X1 to gray planthopper MAD X1 and white planthopper MAD X1 was 95.81% and94.38%,respectively.MAD and MAD X1 proteins are highly conserved in insects,the amino acid sequence similarity between the MAD or MAD X1 proteins of other insects and the MAD or MAD X1 proteins of BPH is more than 70%.2.The relative expressions of the Nlmad and Nlmad X1 were up-regulated at the 4th and 5th instars of BPH.The Nlmad relative expression level of long-winged BPH was significantly higher than that of short-winged BPH at the 4th and 5th instar and adult stage,and the Nlmad X1 relative expression level of long-winged BPH at the 5th instar and female adult stage was also significantly higher than that of short-winged BPH.After interfering with Nlmad of BPH with long/short-winged,the wing area and circumference of adult planthopper decreased significantly,accompanied by the dilution of wing veins,and the shrinking degree of membrane area was much greater than that of leather area and claw area.When Nlmad X1 of short-winged BPH was interfered,the wings of adult BPH also showed a certain degree of shrinking,but the wings of long-winged BPH did not show shrinking,and several kinds of ectopia of wing veins appeared instead.3.Interfering with long-winged BPH Nl In R1,the expression of Nlmad was decreased.Interfering with long-winged BPH Nl In R2 or Nl Fox O,the expression of Nlmad was increased.Interference of Nlmad and Nl Fox O at the same time can partially restore the phenotype caused by interfering with Nl Fox O singly,and most BPH adults develop into intermediate-winged type.It suggested that Nlmad was regulated by the IIS,Nlmad mediated Nl Fox O to regulate wing morphs differentiation of BPH.The results of this study will enrich the theory of molecular mechanism of wing development and wing morphs differentiation of BPH.This study provides theoretical basis for analyzing the mechanism of BPH disaster and developing sustainable environmental friendly control technology system.