Studies On The Resistance Of Clostera Anachoreta Experimental Populations To Transgenic Bt Poplar

The Clostera anachoreta experimental populations of anti-transferred Bt gene poplars were selected through the F2 generation screening method by feeding Clostera anachoreta larvae with different transgenic Bt gene poplar leaves (CK, Pb17, Pb29). The mortality of F2 populations under different Bt concentrations and BtCry1Ab/1Ac contents of larvae were measured. The experimental populations of Clostera anachoreta fed on differential Bt expressive quantity poplar leaves were analyzed with SSR. The genetic structure diversity, genetic diversity and genetic differentiation of Clostera anachoreta experimental populations were compared. The genetic structure variety of experimental populations were analyzed on the DNA level, The results revealed the Clostera anachoreta experimental populations resistance mechanism to transgenic Bt gene poplar. The main results are as follows:1. The pest resistance to Bt could be monitored by F2 generation screening method quickly and efficiently. 6 experimental populations of Clostera anachoreta (L-CK, L-Pb17, L-Pb29, D-CK, D-Pb17, D-Pb29) which were resisted to poplars with Bt gene were obtained in the lab.2. Under the same Bt concentrations stress, the mortality of Clostera anachoreta experimental populations was highest in 1st instar larvae and lowest in 4th instar larvae. The mortality of the 4 instar larvae ranked from high to low was 1st>2 ed >3 rd>4th, indicated that the Clostera anachoreta experimental populations mortality decreased with growth, i.e. the pest resistance to Bt enhanced with age. Under different Bt concentrations stress, the mortality of Clostera anachoreta experimental populations was highest in the population fed on Pb29 transgenic poplar leaves and lowest in population fed on CK poplar leaves. The mortality of 3 experimental populations ranked from high to low was Pb29>Pb17>CK, showed that Clostera anachoreta experimental populations mortality increased with Bt concentrations.3. Under different Bt concentrations stress, BtCry1Ab/1Ac content in larvae fed on Pb29 poplar leaves was higher, whereas lower in larvae fed on Pb17 poplar leaves BtCry1Ab/1Ac content in Clostera anachoreta experimental populations increased with Bt concentrations. Under same Bt concentrations stress, the body BtCry1Ab/1Ac content difference between Clostera anachoreta death and survival was not significant, i.e. L-17 experimental population BtCry1Ab/1Ac content and D-17 experimental population BtCry1Ab/1Ac content is equivalent, L-29 experimental population BtCry1Ab/1Ac content and D-29 experimental population BtCry1Ab/1Ac content is equivalent, showing that the relationship between insects body BtCry1Ab/1Ac content and feeding time were remained suspending.4. 10 pairs of primers were selected for the genetic analysis of Clostera anachoreta by SSR marker. 68 alleles were detected within 6 populations, the average number of alleles on each locus was 6.8, and the average percentage of polymorphic locus was 96.67%. Within each experimental population, the average effective number of allele (Ne) was 2.2399, and the average expected heterozygosity (He) was 0.5167, which indicated that the genetic diversity of these 6 populations was relatively higher than others. The level of genetic diversity of the 6 experimental population ranked from high to low was D-Pb29>L-Pb17>D-Pb17>L-Pb29>D-CK>L-CK.5. The average coefficient of genetic differentiation (FST) among 6 populations was 0.28, which proved that the differentiation of Clostera anachoreta was mainly attributed to the differentiation within populations. The result of cluster analysis showed that 6 populations were divided into three groups, i.e. L-CK and D-CK, L-Pb29 and L-Pb17, D-Pb29 and D-Pb17. It was proved that the population differentiation of Clostera anachoreta experimental populations could be affected significantly by transgenic Bt gene poplar and the feeding time.