Regulation Of Histone Deacetvlase Gene Family On The Reproduction Of The Brown Planthopper

The brown planthopper(BPH),Nilaparvata lugens Stal.is a destructive pest for rice,exemplifying the delphacid planthoppers in the order Hemiptera.The BPH is characterized by its high fecundity and overlapping generations,thus causing frequently out'breaks in China and many other Asian countries.Histone acetylation is a type of chromatin modification and regulates many cellular processes.However,its regulatory role on insect fertility was rarely reported.In this study,we identified 12 members of histone deacetylases(HDACs)in the brown planthopper(BPH),including the six classic HDAC family genes of zinc-dependent,designated NlHdacl,1NlHdac3,NlHdac4,NlHdac6,NIHdacll,NlHdac11-l,the six sirtuin family genes of NAD+-dependent,designated NlSirt1,NISirt2,NlSirt3,NlSirt4,NlSirt6,NlSiirt7.The effect of each gene on the reproduction of brown planthopper was preliminaryly analyzed by RNAi-mediated silencing experiments.Based on this,the further study of NlHdac1 was conduted.The main results obtained in this paper are as follows:(1)Temporal analysis of gene expression showed that NlHdac1 was highly expressed in the egg stage,while the expression ofother genes was ubquitiously expressed.(2)Tissue distribution analysis showed that NlHdac1,NlSirt6 and NISirt7 were highly expressed in the ovary of female,NlHdac6 was highly expressed in the digestive tract,and other genes were ubquitiously expressed.(3)RNAi-mediated silencing experiments showed that silencing NlHdac1 and NlHdac4 impaired ovary development,and silencing NlHdac1,NlHdac3 resulted in abnormal ovipositors,dysfunction impairment of these three genes seriously affected the planthopper fertility,while silencing other members of histone deacetylases have no significant effect on fertility.(4)Silencing of NlHdac1 and NlHdac4 genes in female adults revealed that only silencing NlHdacl could widely increased acetylation level of histones H3 and H4 in ovaries,indicating NlHdac1 is the major histone deacetylase in ovaries of BPH.(5)Further analysis by RNA sequencing(RNA-seq)revealed that NlHdacl regulated ovary development and oogenesis via multiple signaling pathways including the mTOR pathway.(6)Silencing of NlHdacl significantly impaired fertility of BPH males.However,there was no significant difference in sperm vitality between dsNlHdac1 and dsGfp treated males.(7)Males with NIHdac1 knockdown failed to make courtship songs,and thus they lose the right to mate with wild females.The preliminary results of this paper not only help to elucidate the mechanism of HDACs regulating insect reproductive function,but also provide a reference for the prevention and control of planthopper.