The Functional Explore Of Three Salivary Genes In White-backed Planthopper,Sogatella Furcifera

Sogatella furcifera(Horvath)is one of the most important pests of rice.It can not only damage rice by feeding the phloem juice of rice,but also transmit rice black stripe dwarf virus,which leads to heavy economic loss.In the feeding interaction between S.furcifera and rice,S.furcifera secretes watery and gel saliva.These two kinds of saliva play important roles in the degradation of plant tissue,inhibition or induction of plant defense response.In this study,three genes of multicopper oxidase 4,endo-?-1,4-glucanase and mucin were selected to investigate the role of feeding and the induction of plant defense response.It will provide a further theoretical basis for the integrated control of S.furcifera.The main results are as follows:1.Silencing of multicopper oxidase 4.Based on the sequence analysis of MCO4 gene,MCO4 was deduced as the secretory protein of S.furcifera.The survival rate of S.furcifera silenced MCO4 is significantly lower than that of normal S.furcifera.Compared with TN1,the expression of MCO4 in IR26 was significantly increased,and the adult weight was significantly reduced.It is suggested that MCO4 is an important gene in the feeding process,which plays an important role in overcoming the rice defense response and completing the feeding process of S.furcifera.2.Silencing of SfEG1.SfEG1 gene is a highly expressed in salivary gland of S.furcifera.By comparing with the homologous sequence of Nilaparvata lugens(St?l),the 1430 bp gene length of SfEG1 was obtained.The SfEG1 gene was successfully silenced by microinjection.After silencing SfEG1,the survival rate,and adult body weight of S.furcifera were decreased significantly in TN1 rice.EPG technique was used to detect the feeding behavior.The results showed that the feeding behavior of S.furcifera was obviously disturbed after SfEG1 silenced.S.furcifera could not obtain the phloem juice of rice smoothly,and the feeding process was interrupted often.The level of Jasmonic acid and Salicylic acid in TN1 rice infected by S.furcifera with silenced SfEG1 gene were detected.The results showed that the level of Salicylic acid in TN1 rice was significantly lower than that in ds GFP treated group at 6,12,24,48 h after SfEG1 silenced,but the content of Jasmonic acid was not affected.Therefore,we can deduce that SfEG1 is an important gene for the feeding of S.furcifera,which plays an important role in inducing plant defense response.3.The interaction study between mucin silencing and rice.The mucin gene plays an important role in the formation of salivary sheath of S.furcifera.The content of Jasmonic acid and Salicylic acid in rice was significantly lower than that in the control group at 24 hours.We speculate that this may be due to the silenced of mucin gene.When feeding for 24 hours,the feeding behavior of S.furcifera is continuously disturbed.It leads to the weakening of the detection ability,and further affects the rice defense response.