Selective and stable elimination of endosymbionts from multiple-infected whitefly Bemisia tabaci by feeding on a cotton plant cultured in antibiotic solutions

The maternally heritable endosymbiont provides many ecosystem functions.Antibiotic elimination of a specific symbiont and establishment of experimental host lines lacking certain symbionts enable the roles of a given symbiont to be explored.The whitefly Bemisia tabaci(Gennadius)in China harbors obligate symbiont Portiera infecting each in-dividual,as well as facultative symbionts,such as Hamiltonella,Rickettsia and Cardinium,with co-infections occurring relatively frequently.So far no studies have evaluated the selectivity and efficacy of a specific symbiont elimination using antibiotics in whiteflies co-infected with different symbionts.Furthermore,no success has been achieved in estab-lishing certain symbiont-free B.tabaci lines.In this study,we treated Hamiltonella infected B.tabaci line,Hamiltonella-Rickettsia-co infected line and Hamiltonella-Cardinium co-infected line by feeding B.tabaci adults with cotton plants cultured in water containing ri-fampicin,ampicillin or a mixture of them,aiming to selectively curing symbiont infections and establishing stable symbiont-free lines.We found ampicillin selectively eliminated Cardinium without afecting Portiera,Hamiltonella and Rickettsia,although they coex-isted in the same host body.Meanwhile,all of the symbionts considered in our study can be removed by rifampicin.The reduction of facultative symbionts occurred at a much quicker pace than obligate symbiont Portiera during rifampicin treatment.Also,we measured the stability of symbiont elimination in whitefly successive generations and established Rickettsia-infected and Cardinium-infected lines which are absent in natural populations.Our results provide new protocols for selective elimination of symbionts co-existing in a host and establishment of different symbiont-infected host lines.

The novel roles of circular RNAs in metabolic organs

Circular RNAs(circRNAs)with a covalently closed loop structure which was different with linear RNAs,recently re-merged as novel regulator and exerted function in multiple biological processes.Through deep RNA sequencing(RNA-seq)technology coupled with bioinformatic analyses,a number of circRNAs has been identified.Moreover,circRNAs exhibit tissue-and development-specific expression indicating their potential biological significance.Actually,function of circRNAs as miRNA sponge has been well demonstrated in some diseases,besides,circRNAs also could function as RNA binding protein sponge and regulate alternative splicing and gene transcription.Notably,Emerging evidences showed that circRNAs played a pivotal role on the development of diseases including atherosclerotic vascular disease,neurological disorders and liver diseases,and served as diagnostic or predictive biomarkers of some diseases.This review mainly discusses the current advance of circRNAs as regulator involved in many diseases,and highlights circRNAs which have been well elucidated biological and pathogenic mechanism.