The Regulatory Roles Of Two Male-derived Genes In Female Fecundity And Population Growth In Brown Planthopper,Nilaparvata Lugens (St(?)l)

The brown planthopper(BPH),Nilaparvata lugens(Stal)is a typical monophaous rice pest whose resurgence can be elicited by multiple insecticides.Previously,intensive studies have been undertaken regarding the chemical agents-induced female fecundity to explore mechanisms underlying BPH resurgence,however,insights into the roles played by male insects in female fecundity are rather scarce and limited.The present study focused on mating involved by both males and females to investigate the potential implications of male-derived genes NlSPATA5 and MlPHF7 in parental female fecundity and its offspring population via feeding-based RNAi,which may provide an novel elucidation for BPH resurgence mechanisms from the perspective of male-induced fecundity.1.Silencing the NISPATA5 gene influences female fecundity and its offspring populationThe qPCR analysis of tissues indicated that the NISPATA5 gene was specifically expressed in the male internal reproductive organs(IROs)and fat bodies.Dietary dsNlSPATA5 treatments led to reduced NISPATA5 expression,with an average decrease of circa 41.0%～67.3%in different developmental stages(1,3,5,and 7 days post-emergence,DPE),and a 29.7%drop of the protein content in male accessory gland,as well as vas deferens deformity.In addition,NISPATA5 suppression exerted pronounced effects on female fecundity,diminishing the number of laid eggs by 32.9%,extending the preoviposition period by 31.3%,reducing the progeny by 53.7%and hatching rate by 16.9%.While no significant differences in oviposition period and offspring sex ratio compared to controls were observed after NISPATA5 depletion.Besides,dsNlSPATA5 treatment impeded the ovary development,and reduced the protein content of ovary and fat body by 27.9%and 49.6%respectively,and down-regulated Nlvg expression by 34.4%.At both 2DPE and 3DPE,YLS abundance of fat bodies was substantially decreased upon dsNlSPATA5 treatment.However,dietary dsNlSPATA5 treatments resulted in no significant differences for the longevity and body weight of males and females.2.Silencing the NIPHF7 gene influences female fecundity and its offspring populationThe qPCR analysis of NIPHF7 gene in the tissues showed that like the NISPATA5,NIPHF7 gene was specifically expressed in the internal reproductive organs and fat bodies.Dietary dsNlPHF7 treatments resulted in an average decrease of 44.3%～60.2%for NIPHF7 expression at different developmental stages(1,3,5,7days post-emergence,DPE),and reduced content of male accessory gland protein and arginine by approximately 16.6%and 37.6%respectively,as well as body weight down by about 21.3%in males,along with malformed vas deferens and testicular.In addition,silencing NlPHF7 strikingly implicated female fecundity,including reduced number of eggs laid(40.9%down),reduced offspring populations(66.1%down)and decreased hatching rate(18.0%down),but there were no recorded differences in preoviposition period,oviposition period and offspring sex ratio.NlPHF7 suppression also retarded the ovary development,decreased the female body weight by roughly 14.5%,reduced the protein content in ovary by circa 40.9%,and down-regulated Nlvg expression by about 53.2%.At 2DPE and 3DPE,NlPHF7-suppressing treatments led to decreased number of YLS in fat bodies of adult females.However,for neither females nor males,dietary dsNlPHF7 treatments had no significant effects on the longevity.