Effects Of Symbiotic Bacteria Rickettsia On The Biological Characteristics Of Bemisia Tabaci

Bemisia tabaci(Gennadius)is a genus of the genus Papilioceae,also known as cotton whitefly(Cotton whitefly)or sweet potatoes(Sweetpotato whitefly),is the world’s most dangerous agricultural pests one.Rickettsia is one of the main symbiotic bacteria in Bemisia tabaci,which has an important effect on the growth and development of Bemisia tabaci and its resistance.In this paper,we selected the most widely distributed B~-type and Q-type Bemisia tabaci(Gennadius)strains,and analyzed the common symbiotic bacteria species,infection rate and Rickettsia phylogenetic relationships in B and Q populations by conventional PCR.Reproductive screening method to establish a pure Rickettsia positive and negative B~-type Bemisia tabaci populations,for the follow-up experiments to provide research basis.At the same time,the influence of Rickettsia on the biological characteristics of Bemisia tabaci was studied in order to understand the interaction between secondary symbiotic bacteria and host Bemisia tabaci.Finally,we designed the hybridization experiments between Rickettsia positive type B and Rickettsia negative type B and Q type,with a view to reveal the effect of Rickettsia on the reproductive isolation of B and B.biotype Bemisia tabaci.The main findings are as follows: 1.Type and prevalence of common symbiotic bacteria of B~-type and Q-type Bemisia tabaciPCR results showed that there were native symbiotic fungi Portiera infection in Btype and Q-type Bemisia tabaci,while the species of secondary symbiotic bacteria showed differences in the two different biotype Bemisia tabaci species: B~-type Rickettsia positive tobacco There are four common bacteria,such as Portiera,Rickettsia,Hamiltonella and Olo,which belong to Portiera,Hamiltonella,Olo and Cardinum.In addition,the infection rates of the above common common symbiotic bacteria were also different among the two populations: the infection rates of Hamiltonella and Olo strains were 93.3% and 97.8% in Rickettsia positive type B,respectively.In Rickettsia negative The infection rates of Cardinum,Hamiltonella and Olo in Q-type population were 31% and 91% respectively,which indicated that the infection rate of B~-type population was 76% and 91%,93.1%,91%.2.Single-to-breeding breeding Screening of type B Rickettsia positive,type B Rickettsia negative natural population and positive Bemisia tabaci Rickettsia 2.Screening of Rickettsia positive and negative B~-type Bemisia tabaci populations and detection of Rickettsia at each age of positive Bemisia tabaciThe B~-type Rickettsia positive Bemisia tabaci and B~-type Rickettsia negative Bemisia tabaci(Gennadius)were selected by single-pair breeding.Purity detection was performed every 1 generation and the purity remained stable.In addition,the screening of Rickettsia positive Bemisia tabaci was detected,and Rickettsia was distributed in the sta ges of egg,age 1,age 2,age 3,age 4,pseudo pupa,adult and so on.The sequence of 16 Sr RNA gene was compared with NCBI-BLAST,and the phylogenetic tree was constructed.The results showed that the Rickettsia genus B in the Bicked Rickettsia population was the Bellii group.3.Phylogenetic Relationships of Rickettsia in Rickettsia-positive B~-type Bemisia tabaciBased on the NCBI-BLAST comparison of Rickettsia,the phylogenetic tree was constructed.The results showed that the Rickettsia genus was located in the Bicked Bemisia tabaci species.4.Effects of secondary symbiotic bacteria Rickettsia on the biological characteristics of Bemisia tabaci B – biotypeCotton-mediated Rickettsia horizontal transmission can significantly improve the biological characteristics of the corresponding Bemisia tabaci.There were differences in the developmental days of Rickettsia positive Bemisia tabaci(Gennadius)in positive,negative plants,egg stage,third instar stage and pseudo-pupal stage.B~+C + shorter than B + C~-The growth period of the former was longer than that of the latter.There was no difference between the first instar,the second instar and the 4th instar.The results showed that the plant infection Rickettsia had different effects on the developmental period of Bemisia tabaci.For Rickettsia-negative Bemisia tabaci,the presence of Rickettsia in the host plant has no effect on its growth and development except in the egg stage,and the re is no significant effect at other stages.B~-C~+ group of egg development period of 5.07 d,B~-Cfor 5.50 d.The results of different treatments at the same developmental stage showed that the treatment of Rickettsia positive Bemisia tabaci in the other age groups was shorter than that of the Rickettsia negative group.The incidence of Bemisia tabaci was also shorter than negative,indicating that Rickettsia could shorten the developmental period of Bemisia tabaci(Gennadius).The survival rates of B~+C~+,B~+C~-,B~-C + and B~-C~-were also different: the difference was significant,and the difference was not significant,and the difference was not significant(P <0.05)(P <0.05).The survival rate of B~+C~+,B~+C~-,B~-C~+ and B~-C~-were decreased by 75.00%,70.00%,56.67% and 41.67%,respectively.Cotton-mediated Rickettsia horizontal transmission also affected the reproductive characteristics of host Bemisia tabaci(Gennadius): Rickettsia positive Bemisia tabaci(Gennadius)was not significantly different between positive and negative plants,while negative Bemisia tabaci was positive The average life span of F1 was significantly decreased,and the life span of B~+C~+,B~+C~-,B~-C~+ and B~-C~-4 were shortened in turn.In addition,the average single female fecundity was decreased and the difference was significant The range of eggs was 101-195,98-165,87-135,39-109.Indicating that the presence of Rickettsia will affect the production rate and longevity of Bemisia tabaci.Similarly,the presence of Rickettsia in the F1 generation of Bemisia tabaci F1 had a significant effect: "B~-C~-" and "B~-C~+" were significantly lower than those of "B~+C + " and " B +C~-" treatment groups,while there was no significant difference between Rickettsia positive and Rickettsia negative group.The survival rate of " B~+C~+ " treatment group was 73.33%," B~-C~-" The survival rate of the treatment group was 31.67% 5.Effects of Rickettsia on Reproductive Isolation of B~-type and Q-type Bemisia tabaciThe results showed that Rickettsia had no effect on the reproductive isolation of Btype and Q-type Bemisia tabaci(Gennadius),and the increase of the number of males had some disturbance effect on the female parthenogenetic and oviposition.,The stronger the interference effect,but the effect on the sex o f oviposition in addition to 1:2 and 1:5 treatment group between the differences,the other treatment group has little effect;the increase in the number of males can also increase parthen Rickettsia could increase the fecundity of Bemisia tabaci,but had little effect on the fecundity and fecundity of Bemisia tabaci The fecundity of Q-type fecundity was significantly higher than that of Rickettsianegative B~-type male worms,and the fecundity of Q-type Bemisia tabaci was significantly higher than that of Q-type Reproductive hatchability;Rickettsia can improve the female fertility rate of B~-type Bemisia tabaci.In conclusion,Rickettsia could affect the fecundity and yield of Bemisia tabaci B~-biotype,but had little effect on its emergence rate.