Effect Of The Intracellular Bacterial Symbionts On Different Body-Color Biotypes Of Sitobion Avenae (Fabricius)

Sitobion avenae (Homoptera:Aphididae), is one of the most important pests to cereal crop, distributing all over the world. Moreover, it is an efficient vector of several plant virus, especilly Barley Yellow Dwarf Virus (BYDV). Just like other aphids, based on the tipical characteristic-polymorphism, Sitobion avenae has the green and red body color biotypes. So far, the mechanism of biotype is unknown.Buchnera aphidicolia is the primary symbiotic bacteria of the aphid. The Aphid- Buchnera symbiosis is probably the most perfect and harmonious model for the encaryot and bacteria. In addition, it seems likely to be related with biotype that Buchnera provides metabolic enzymes for the aphid's biosynthesis in order that it can adapt to new host. At present, the role of symbiotic bacteria in the biotypes mutation and its mechanisms haven't been reported yet.In order to reveal the effects of symbiotic bacteria on the different biotype aphid, the two biotype Sitobion avenae were treated with the broad spectrum antibiotic, rifampicin. At the same time, it comparably analysed the color biotypes in the four directions. The results are as follows:1.The influence of symbiotic bacteria on the green aphids growth, development and reproduction.Compared with symbiotic aphids, the results showed that Bacteria-free aposymbiotic aphids displayed reduced adult fresh weight; prolonged duration of the nymphs; increased nymph duration effective accumulated temperature (EAT); reduced threshold temperature; prolonged length a generation; decreased net reproduction rate and intrinsic increases rate. Besides, both symbiotic aphids and Bacteria-free aposymbiotic aphids nymphs duration decreased with increased temperature. the top of productivity for both of them were all in the 21℃.2. Molecular diagnosis of Buchera bacteria from two body-color biotypes aposymbiotic aphidsThrough light microscope and PCR technique, there still exist Buchnera in the two biotype aphids after rifampicin treated for 5 days and 10 days. After rifampicin treated for 15 days, buchnera don't exist. It is significance that Buchnera was disrupted completely after rifampicin treated for 15 days Through light microscope and PCR technique. 3. The impact of Buchnera on the total protein content of the two body-color biotypes aphids.Comparing to symbiotic aphids, As for per milligram aphid and per aphid, the content of the total protein of the Green aposymbiotic aphids reduced by 47% and 83%, while the the Red ones reduced by 71% and 91%. This meaned both green aposymbiotic and red aposymbiotic aphids, the nutrition condition obviously became worse, and red aphids worse than green ones.4. The impact of Buchnera on the enzymes of ALT, AST, GS of the two body-color biotypes aphids.Comparing to symbiotic aphids, the activity of ALT, AST in the rifampicin-treated Green aphids reduced by 50%,58%, however, the red ones reduced by 82%, 72%. This means that the effect of the Buchnera on the transferase of amino acid in the Red aphids is much more than the Green aphids.On the one hand, comparing to symbiotic aphids, the activity of GS in the green aphids increased by 118% while the one in the red aposymbiotic aphids increased by 164%. This means that the effect of the Buchnera on the transferase of ammonia in the Red aphids is much more than the Green aphids.This study offer theoretical explain for the evolution relation both Buchnera and aphid body color to change, and it hasn't been reported yet that studying of Buchnera and Aphids with the way of the life table.