Secondary-symbiotic Bacteria In Wheat Aphid And It's Effect On Transmission Effciency Of Barlley Yellow Dwarf Virus (BYDV)

Aphids are responsible for major crop losses in world agriculture,not only directly by feeding on leaves,stalks and ears,but also indirectly by excreting honeydew and transmitting viruses.In the process of long-term coevolution,symbionts and its wheat aphid have formed close and mutualistic relationship,symbionts play an important role in the spread of barley yellow dwarf virus.Therefore,it is very important to understand the relationship between secondary symbiotic bacteria and BYDV transmission efficiency.Our study used specific PCR technology to detect secondary symbiotic infections and virus transmission efficiency of different clone of wheat aphids.The main findings are as follows:Using 16 SrDNA specific primers to detect six common secondary endosymbiontson wheat in different regions?The result showed that:S.avenae : the infection rate of R.insecticola on S.avenae were 53.3% in Bao Ji,the other clone were not detected;The infection rate of Hamiltonella defensa and Spiroplasma were 100%;The infection rate of Wolbachia were closely 100%;The infection rate of Rickettsia were respectively 76.7%?86.6% in WN and XYS.graminum : The infection rate of R.insecticola were respectively 36.7%?43.3%,the other clone were not deected;The infection rate of Hamiltonella defensa were 100%,except XY(93.3%);The infection rate of Rickettsia were 100%;The infection rate of Wolbachia were 100%,except BJ(93.3%);the infection rate of Spiroplasma were 100%,except WN 16.7%.The results showed:(1)The largest difference between R.insecticola and Spiroplasma in wheat aphid;(2)different clone of whead aphid harbor different secondary endosymbionts;(3)whead aphid exist multiple infections;(4)the refection of secondary endosymbionts were different on S.avenae and S.graminum2.BYDV-GAV transmission efficiency of different geographic population wheat aphids: S.avenae: The virus transmission efficiency of No.1 and No.2 spots in BJ population was 75% and 73.3%,respectively.The transmission efficiency of other populations was 100%.S.graminum: the lowest of transmission efficiency was 73.3% in XY,the highest transmission efficiency was 100% in TS.3.Based on the correlation analysis of the infection rate of secondary symbiotic bacteria and virus transmission efficiency,it was found that the increase of the content of R.insecticola caused an increase in the transmission efficiency of BYDV-GAV.This indicates that R.insecticola was conducive to the transmission of BYDV-GAV.