Chitinase-transformed Arabidopsis Thaliana Enhances The Virulence Of HearNPV Against Helicoverpa Armigera(Lepidoptera: Noctuidae)

Chitinase derived from Heliocoverpa armigera Nucleopolyhedrovirus(HearNPV) plays essential roles in insect liquefaction and horizontal transmission between hosts. Additionally, Chitinase can enhance infection efficiency and virulence of Hear NPV. Chitin layer is an important structure in insect digestive track to protect it from injuries by intestinal contents. In this study, We expect to constract Arabidopsis thaliana plants vector, Agrobacterium tumefaciens mediated transformation of Arabidopsis inflorescence infection method of Chitinase exogenous gene, and carried out its Helicoverpa armigera nuclear polyhedrosis virus(Helicoverpa armigera nucleopolyhedrovirus, Hear NPV) synergy study, Major findings are following:1. The genetic transformation of Chitinase gene was performed by flor-dip transfer method, and 6 putative transformants of plants lines were selected by Basta. PCR analysis shows that the Chitinase gene can be detected in the genomes of all these 6 lines.2. Real-time PCR analysis reveales that there were Chitinase gene transcripts accumulated in leaves of homozygous transgenic lines A-F. Among these 6 lines, line A was significantly higher level of gene expression than other lines(P<0.01). Meanwhile, line D was the lowest expression level and there was no expreesion found in wild-type.3. Enhancement trial shows that LT50 and LT90 of H. armigera when fed with line A and Hear NPV reduced 36.17% and 40.33%, respectively, as compared to the non-transgenic plants control. When feeding them with line D and Hear NPV, LT50 and LT90 reduced 18.08% and 25.14%, respectively.4. Quantitative analysis of Hear NPV copies in intestinal cells at different treatments shows that when fed larvae with the transgenic plants and Hear NPV, the copy numbers were significantly higher than the control treatments, indicating the virus Hear NPV were much more quickly and more quantities to infect the intestinal cells of cotton bollworms which fed with chitinase-transformed Arabidopsis thaliana and Hear NPV.5. Hear NPV Baculovirus productivity analysis indicates that treatment line A and Hear NPV was significantly higher than it in treatment line D and Hear NPV. Productivity in control treatment was significantly lower than transgenic plants-containing treatments.6. Weight gain analysis of H.armigera shows that the weight differences between virus-free treatments were not significant, as well as they in Hear NPV-containing treatments. Compared to larvae which fed without Hear NPV, development of larvae which fed on both A.thaliana and Hear NPV were significantly inhibited.The study reveals that the Arabidopsis gene transfer Chitinies bollworm polyhedrosis virus particles simultaneously use more quickly into the insect midgut cell when fed bollworm, cotton bollworm and helps the virus Hear NPV added in, as well as improve the speed and virus insecticidal insecticidal efficiency of the cotton bollworm.