| The Rhopalosiphum padi is the main wheat pest in my country and is listed in the list of Class I crop pests and diseases.R.padi feeds on rhizomes and lower leaf sheaths of wheat seedlings for a long time.With the increase of temperature,aphids will multiply rapidly and spread to the whole wheat seedlings.There is a kind of obligate symbiotic bacteria Buchnera aphidicola in aphids,which is called primary endosymbiotic bacteria.It occupies the main part of the endosymbiotic bacteria and is mutually beneficial with the host aphids.It can provide nutrients to the host,change the reproductive characteristics of the host,and affect other physiological functions and ecological features.Under the background of this research,the antibiotic rifampicin was used to reduce the content of B.aphidicola in R.padi,and to explore whether B.aphidicola would affect the reproduction and feeding of R.padi.The research results will provide a theoretical basis for the development of new control methods for the R.padi.The main research results are as follows:1.Establishment of a method for the detection of rifampicin in wheat seedlings and R.padi.Qu ECh ERS-UPLC-MS/MS technology was used to detect the stems and leaves of wheat seedlings and the R.padi raised on them in 100 mg/L rifampicin-treated and control groups,rifampicin could be effectively detected in the stems and leaves of wheat seedlings and R.padi in the rifampicin-treated group,but no rifampicin could be detected in the control group of wheat seedlings and their reared aphids.In the measurement data,it was found that under the same culture conditions,the detected amount of rifampicin showed a trend of stems of wheat seedlings > leaves of wheat seedlings > R.padi,which is consistent with the allocation principle that absorption of rifampicin from the roots and flow through the stems to the leaves after feeding.Practice has proved that this method is suitable for the detection of rifampicin in wheat seedlings and R.padi.2.Effect of rifampicin treatment of wheat seedlings on the longevity and reproduction of R.padi.Statistical analysis the four groups of 1 mg/L,5 mg/L,20 mg/L,100 mg/L feeding with rifampicin solution and the control group showed that they are no significant difference.Statistical analysis of the number of nymph in 1 mg/L,5 mg/L,20 mg/L,100 mg/L four groups of rifampicin solution and the control group of R.padi,found that the average total number of nymph of each R.padi was respectively 25.0 aphids,11.6 aphids,15.2 aphids,17.8 aphids and 66.3 aphids.When the feeding site was fixed and the number of nymph per R.padi was counted,it was found that the average total number of nymph per aphid on the stems and leaves of 1 mg/L rifampicin solution were 23.4 aphids and 34.7 aphids;the average total number of 5 mg/L rifampicin solution were 17.2 aphids and 16.2 aphids;the average total number of control were 71.6 aphids and 58.0 aphids.The number of nymphs per aphid in the rifampicin treatment group was significantly lower than that in the control group,and the rifampicin treatment had a greater impact on the number of nymphs per aphid in the stems than in the leaves.According to the statistics of the number of nymph of each R.padi in different parts of the wheat seedlings,it was found that the average total number of nymph of each R.padi in the stem and leaves in the 1 mg/ rifampicin solution treatment were 7.6 aphids and 24.7aphids,the average total number in the 5 mg/L rifampicin solution treatment were 2.0aphids and 14.9 aphids,the control group were 42.1 aphids and 28.5 aphids.The results showed that aphids in the rifampicin treatment group were more likely to reproduce nymphs on the leaves,while the control group preferred to reproduce nymphs on the stems.Therefore,rifampicin treatment had an effect on the reproduction tropism of R.padi,and this change of reproduction tropism from stem to leaf increased with the increase of rifampicin concentration.3.Effect of rifampicin treatment of wheat seedlings on the feeding tropism of R.padi.According to the statistics of the first feeding site of R.padi,show that in the rifational treatment group and the control group the R.padi were picked up at the stems and the leaves,most of them start to feed on the stems,Statistices the number of feeding days of each R.padi in different parts,it is found that 1 mg/L rifampic treatment group aphid feeding stems and leaves have an average number of days of 8.2 d and 17.7 d,5 mg/L rifampic treatment group of 4.7 d and 23.8 d,the control group of 13.1 d and 13.4 d.Therefore,after treatment of rifampicin,R.padi is demonstrated to have a feeding tropism to leaf,and with the increase of rifampicin concentration,this tendency is earlier and the number of aphids that feed the leaf is increase.4.Effect of rifampicin treatment of wheat seedlings on the content of symbiotic bacteria B.aphidicola in R.padi.By comparing the microbial component of R.padi in 5 mg/L rifampicin treatment group and the control group on the fifth day,it was found that B.aphidicola dominated in the R.padi feeding on the stem and the leaf,with a proportion of more than 96%,and it have not significant difference.Therefore,q RT-PCR was used to further detect the difference in the content of B.aphidicola in the 100 mg/L rifampicin-treated group and the control group.The result display that the content of B.aphidicola in R.padi in the rifampicin treated was significantly lower than that of the control group for 5-day-treated.The B.aphidicola content for the 13-day-treated in R.padi was fetermined.Compared with other groups,it was significantly lower,indicating that rifampicin treatment had a continuous effect on the content of B.aphidicola.In addition,after rifampicin treatment,the content of symbiotic bacteria B.aphidicola in the R.padi feeding on the stems of wheat seedlings was significantly lower than that in the leaves.In conclusion,The effect of rifampicin treatment on reproduction and feeding of R.padi was the same as the effect on the content of symbiotic bacteria B.aphidicola in R.padi.Therefore,endosymbiotic bacteria B.aphidicola are very likely to affect the reproduction and feeding of R.padi. |
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