Studies On The Function Of Vitellogenin In Male Green Lacewing,Chrysopa Pallens

The green lacewing,Chrysopa Pallens,is an important natural predator,attacking aphids and other agricultural and forestry pests.It is famous for broad distribution,wide prey spectrum and excellent reproductive performance,and plays important roles in suppressing pest population and reducing crop loss.Mass propagation is a basis of application of natural enemy insects.Whereas an insight into reproductive physiology of natural enemy insects is helpful to develop techniques for regulating the reproductive process and to promote the commercial production of natural enemy insects.Our previous study revealed that C.pallens contained the female-specific protein Vg.In this paper,the partial mRNA sequence of male Vg gene was cloned,and the effects of male Vg gene expression on male gonad development,male transcriptome and reproductive indexes such as longevity,gonad development,spawning period and fecundity were discussed by means of RNAi,paraffin section,transmission electron microscope and transcriptome sequencing,etc.in this paper,we discussed the effects of male Vg gene expression on male gonad development,male transcriptome,female longevity,gonad development,spawning period,fecundity and other reproductive indexes.The function of Vg gene in male and female reproduction was clarified,and the mechanism of Vg gene was revealed from the point of view of male reproductive effect.It is mainly divided into three parts:1.Cloning and expression Analysis of partial Vg sequence of male Chrysopa Pallens.Part of the m RNA sequence of male Vg gene was cloned,and the spatio-temporal expression pattern was detected at the transcriptional level.It was found that there was no significant difference in the expression of Vg gene in different developmental stages of male worms,and its expression was the highest in the abdomen,which was 2.64 times higher than that in the chest and 3.51 times that in the head.In addition,at the protein level,the Vg of the whole worm and abdomen was composed of 165 kD large subunits and 46 kD small subunits,while the head and chest Vg contained only small subunits.2.Study on the function of Vg Gene in male Chrysopa Pallens.The biological reproductive indexes of males and females after mating were calculated respectively,and the main results were as follows:(1)the direct effect on males: after Vg interference,the lifespan of males was significantly shortened by 3.33 days,the development of testis was delayed,the seminal vesicles were shrunken and deformed,and the development of spermatozoa was delayed.(2)indirect effects on mating females: there was no significant difference in pre-oviposition,spawning period and weekly average fecundity(the first three weeks)between the treatment group and the control group,but the single egg weight,hatching rate and total egg production decreased significantly by 21.61 ug,5.7 % and 49.61 eggs in the first three weeks,in addition,the egg quality of the treatment group decreased significantly,showing a wrinkled state,and the later blackening could not hatch.3.Preliminary analysis of transcriptome data of male worms after RNAi.The transcriptome sequencing of male and uninterfered males after Vg interference was carried out,and the transcriptome data were analyzed.Four target genes,glutathione S-transferase(GSTe1),cytochrome P450 family 302a1(CYP302a1),phospholipase A2(PLA2)and alkaline phosphatase(ALP),were screened and verified,which laid a foundation for follow-up research.