| Potato virus Y (PVY), Tobacco mosaic virus (TMV) and Cucumber mosaic virus (CMV) are main viruses on tobacco in China. Sugarcane mosaic virus (SCMV) can cause maize dwarf mosaic disease and bring down the yield.Two PVY isolates, AQ4 and FZ10, were collected from Shandong and induce mosaic or mottle on tobacco. Both AQ4 and FZ10 are recombinants with PVYN and PVYO strains. The nucleotides (nt) 1-496 and 2497-9700 of AQ4 genome are from isolate Oz (PVYO),and nt 497-2496 from isolate CH-605 (PVYN). The nt 1-496 and 2497-6533 of FZ10 genome are from isolate SASA-110 (PVYO),while nt 497-2496 and 6534-9698 are from isolate CH-605 (PVYN).AQ4 and FZ10 belong to subgroup PVYN:O and PVYNTN. It is reported that amino acid D205, K400and E419 on HC-Pro induce necrosis on tobacco. Although FZ10 contains these three sites, it induces mosaic on tobacco. These results imply that there are other genes or motifs besides HC-Pro which regulate the veinal necrosis symptom.We cloned three fragments (PVY CP 300bp, CMV RdRp 250bp and TMV CP 450bp) from cDNA saved in our lab. We constructed an inverted repeat vector with these fragments. After transformed into RNaseâ…¢-defectived E.coli HT115 and induced by IPTG, epected dsRNA is produced. The dsRNA can reduce the incidence of these virus diseases.After analysising SCMV sequences on NCBI, we found the most conserved sequences in CI, NIb and CP. These areas can also highly induce RNA silence. We cloned fragments from SCMV cDNA and fused them into an inverted repeat fragment. By inserting the fragment into pCAMBIA3301, we constructed the RNAi vector p3301-SCMVCINIb1CPRi.
|
PDF Full Text Request