Construction of rice stripe virus NS2 and NS3 Co-RNAi transgenic rice and disease-resistance analysis / 病毒学报

NS2 and NS3 are two post-transcriptional gene silencing suppressors that are encoded by Rice stripe virus. Gene silencing suppressors are always related to the pathogenicity of viruses. In this study, the cDNA of NS2 and NS3 were recombined by overlapping PCR assays, ligated to the RNAi vector, and inserted into the PXQ expression vector using Pst I; the expressed vector was transferred into calluses induced from seeds of the japonica rice cultivar, 'Nipponbare', using an Agrobacterium-mediated method. Thirty-one T0 transgenic plants were selected by G418 screening. PCR and southern blot analyses confirmed that the target gene was transformed into transgenic rice successfully, and different transgenic plants contained various copies of the gene. The disease resistance assay revealed that T0 transgenic rice had a delayed onset of RSV for approximately 10-20 d, and the accumulation of virus in the transgenic plants was reduced by 30%-50%. This was related to the delayed onset of disease.

Effects of microcystins on expression of apoptosis-associated hepatocyte genes / 中华预防医学杂志

<p><b>OBJECTIVE</b>To deeply explore the effects of microcystins (MC-LR) on Bax and Bcl-2 during the course of MC-LR promoting liver tumor.</p><p><b>METHODS</b>applied to set up the animal model, and the effect of MC-LR promoting liver tumor was evaluated by the Albertgamma-GT methods. And then, the immunohistochemical technique, RT-PCR and image analysis were used to study the expression of the Bcl-2 and Bax during the course of promoting tumor.</p><p><b>RESULTS</b>(1) MC-LR might enhance the positive reaction rate of GGT. The positive reaction rate of GGT in DEN + pure toxin group was 100%, it was significantly higher than the DEN control group 22.22% (P < 0.05). (2) The intension and areas of the protein expression of Bcl-2 in DEN + pure toxin group were 0.0977 and 0.0315, and in DEN control group were 0.0460 and 0.0205, respectively. The expression level of Bcl-2 protein in DEN + pure toxin group were significantly higher than in DEN control group (P < 0.05). Simultaneously, the protein expression of Bax was significantly decreased by MC-LR (P < 0.05). The intension and areas of the expression of Bax in DEN + pure toxin group were 0.0283 and 0.0073, and in DEN control group were 0.0655 and 0.0244 respectively. (3) The mRNA expression of Bcl-2 was significantly increased by MC-LR. The intension of Bcl-2 mRNA expression in DEN + pure toxin group was 2.244, being significantly higher than in the other groups (P < 0.05). However, the mRNA expression of Bax showed no significant difference between DEN + pure toxin and the other groups.</p><p><b>CONCLUSION</b>The expression change of Bcl-2 and Bax should possibly play an important role in the course of MC-LR promoting liver tumor.</p>

Rapid detection of molecular variation of Rice stripe virus in China by PCR-SSCP assay / 中国病毒学

A reverse transcription polymerase chain reaction (RT-PCR) and single-strand conformation polymorphisms (SSCP) assay were applied to rapidly detect the molecular variability in CP and SP genes among seven isolates of Rice stripe virus in China. The PCR results showed that the CP gene of JD isolate and SP gene of PJ isolate could not be amplified. SSCP analysis showed that there were completely different electrophoretic pattern of CP gene among six isolates. To SP gene, SSCP results also discovered polymorphisms. There were five patterns among these isolates, and the pattern of YL and BS isolates were same.

Comparative Analysis of Serological and Molecular Methods for the detection of Rice Grassy Stunt Virus / 中国病毒学

Methods of ELISA, nonradioactive molecular hybridiz ation and RT-PCR were applied in the detection of rice grassy stunt virus (RGSV ). The detection sensitivity of indirect ELISA using antiserum against fusion p rotein GST-NC was 1 mg of infected leaves or 84 ng of purified virus. The metho d of dot hybridization using NC, a DIG-labelled DNA probe was 50 μg diseased l e aves, or 6 ng purified preparations. The detection endpoint of RT-PCR was 10 μg diseased leaves, or 2 ng purified virus preparation. Comparisons of sensitivit y and maneuverability were made among these methods.

Main Plant Diseases Caused by Umbravirus / 微生物学通报

The genomes of umbraviruses do not encode a coat protein, and thus no conventional virus particles are formed in infected plants. Umbraviruses are always coinfected with an assistor virus, which is always a member of the family Luteoviridae, to cause most devastating diseases in some areas. The epidemiology of the umbra-virus-caused disease is largely depended on aphid transmission. The symptomology, occurrence, characteristics of the causal agents, disease control of carrot motley dwarf, groundnut rosette and tobacco bushy top were reviewed detailedly in this article.