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OsRDR6 plays role in host defense against double-stranded RNA virus, Rice Dwarf Phytoreovirus.

Hong W, Qian D, Sun R, Jiang L, Wang Y, Wei C, Zhang Z, Li Y - Sci Rep (2015)

Bottom Line: We found previously that rice RDR6 (OsRDR6) functioned in the defense against Rice stripe virus (RSV), and Rice Dwarf Phytoreovirus (RDV) infection resulted in down-regulation of expression of RDR6.Our result showed that down-regulation of OsRDR6 through the antisense (OsRDR6AS) strategy increased rice susceptibility to RDV infection while over-expression of OsRDR6 had no effect on RDV infection.The accumulation of RDV vsiRNAs was reduced in the OsRDR6AS plants.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, China.

ABSTRACT
RNAi is a major antiviral defense response in plant and animal model systems. RNA-dependent RNA polymerase 6 (RDR6) is an essential component of RNAi, which plays an important role in the resistance against viruses in the model plants. We found previously that rice RDR6 (OsRDR6) functioned in the defense against Rice stripe virus (RSV), and Rice Dwarf Phytoreovirus (RDV) infection resulted in down-regulation of expression of RDR6. Here we report our new findings on the function of OsRDR6 against RDV. Our result showed that down-regulation of OsRDR6 through the antisense (OsRDR6AS) strategy increased rice susceptibility to RDV infection while over-expression of OsRDR6 had no effect on RDV infection. The accumulation of RDV vsiRNAs was reduced in the OsRDR6AS plants. In the OsRDR6 over-expressed plants, the levels of OsRDR6 RNA transcript and protein were much higher than that in the control plants. Interestingly, the accumulation level of OsRDR6 protein became undetectable after RDV infection. This finding indicated that the translation and/or stability of OsRDR6 protein were negatively impacted upon RDV infection. This new finding provides a new light on the function of RDR6 in plant defense response and the cross-talking between factors encoded by host plant and double-stranded RNA viruses.

No MeSH data available.


Related in: MedlinePlus

Accumulation of RDV S2 and S11 genomic RNAs and vsiRNAs in the OsRDR6AS and WT plants.(a) Northern blot assay of RDV S2 and S11 genomic RNAs and vsiRNAs in the OsRDR6AS and WT plants. Plants showing disease symptoms were harvested at 3 wpi. Three pools of infected plants (>10 plants per pool) were harvested from each treatment and used for total RNA isolation. The rRNA or U6 was used as loading control for the assay. (b) Deep sequencing result showing the relative abundance of vsiRNAs from each RDV RNA. The blue bars represent the results from the WT plants and red bars represent the results from the OsRDR6AS plants. (c) Size distribution of RDV-derived small RNA populations based on the deep sequencing data.
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f2: Accumulation of RDV S2 and S11 genomic RNAs and vsiRNAs in the OsRDR6AS and WT plants.(a) Northern blot assay of RDV S2 and S11 genomic RNAs and vsiRNAs in the OsRDR6AS and WT plants. Plants showing disease symptoms were harvested at 3 wpi. Three pools of infected plants (>10 plants per pool) were harvested from each treatment and used for total RNA isolation. The rRNA or U6 was used as loading control for the assay. (b) Deep sequencing result showing the relative abundance of vsiRNAs from each RDV RNA. The blue bars represent the results from the WT plants and red bars represent the results from the OsRDR6AS plants. (c) Size distribution of RDV-derived small RNA populations based on the deep sequencing data.

Mentions: To determine whether RDV symptoms in the inoculated plants were correlated with the levels of RDV RNA accumulation in the infected plants, we analyzed RDV S2 and S11 genomic RNA levels in the assayed plants by Northern blot. Result of the assay showed that the accumulation levels of RDV S2 and S11 RNAs in the inoculated OsRDR6AS transgenic lines were much higher than that in the inoculated control WT plants (Fig. 2a). Further analysis of viral vsiRNAs accumulated in these plants revealed that the levels of RDV vsiRNAs in the inoculated OsRDR6AS transgenic lines were significantly lower than that in the inoculated control plants. This finding indicated that down-regulation of OsRDR6 expression in rice led to a reduction of RDV RNA silencing in the RDV-infected OsRDR6AS transgenic plants.


OsRDR6 plays role in host defense against double-stranded RNA virus, Rice Dwarf Phytoreovirus.

Hong W, Qian D, Sun R, Jiang L, Wang Y, Wei C, Zhang Z, Li Y - Sci Rep (2015)

Accumulation of RDV S2 and S11 genomic RNAs and vsiRNAs in the OsRDR6AS and WT plants.(a) Northern blot assay of RDV S2 and S11 genomic RNAs and vsiRNAs in the OsRDR6AS and WT plants. Plants showing disease symptoms were harvested at 3 wpi. Three pools of infected plants (>10 plants per pool) were harvested from each treatment and used for total RNA isolation. The rRNA or U6 was used as loading control for the assay. (b) Deep sequencing result showing the relative abundance of vsiRNAs from each RDV RNA. The blue bars represent the results from the WT plants and red bars represent the results from the OsRDR6AS plants. (c) Size distribution of RDV-derived small RNA populations based on the deep sequencing data.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4499934&req=5

f2: Accumulation of RDV S2 and S11 genomic RNAs and vsiRNAs in the OsRDR6AS and WT plants.(a) Northern blot assay of RDV S2 and S11 genomic RNAs and vsiRNAs in the OsRDR6AS and WT plants. Plants showing disease symptoms were harvested at 3 wpi. Three pools of infected plants (>10 plants per pool) were harvested from each treatment and used for total RNA isolation. The rRNA or U6 was used as loading control for the assay. (b) Deep sequencing result showing the relative abundance of vsiRNAs from each RDV RNA. The blue bars represent the results from the WT plants and red bars represent the results from the OsRDR6AS plants. (c) Size distribution of RDV-derived small RNA populations based on the deep sequencing data.
Mentions: To determine whether RDV symptoms in the inoculated plants were correlated with the levels of RDV RNA accumulation in the infected plants, we analyzed RDV S2 and S11 genomic RNA levels in the assayed plants by Northern blot. Result of the assay showed that the accumulation levels of RDV S2 and S11 RNAs in the inoculated OsRDR6AS transgenic lines were much higher than that in the inoculated control WT plants (Fig. 2a). Further analysis of viral vsiRNAs accumulated in these plants revealed that the levels of RDV vsiRNAs in the inoculated OsRDR6AS transgenic lines were significantly lower than that in the inoculated control plants. This finding indicated that down-regulation of OsRDR6 expression in rice led to a reduction of RDV RNA silencing in the RDV-infected OsRDR6AS transgenic plants.

Bottom Line: We found previously that rice RDR6 (OsRDR6) functioned in the defense against Rice stripe virus (RSV), and Rice Dwarf Phytoreovirus (RDV) infection resulted in down-regulation of expression of RDR6.Our result showed that down-regulation of OsRDR6 through the antisense (OsRDR6AS) strategy increased rice susceptibility to RDV infection while over-expression of OsRDR6 had no effect on RDV infection.The accumulation of RDV vsiRNAs was reduced in the OsRDR6AS plants.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, China.

ABSTRACT
RNAi is a major antiviral defense response in plant and animal model systems. RNA-dependent RNA polymerase 6 (RDR6) is an essential component of RNAi, which plays an important role in the resistance against viruses in the model plants. We found previously that rice RDR6 (OsRDR6) functioned in the defense against Rice stripe virus (RSV), and Rice Dwarf Phytoreovirus (RDV) infection resulted in down-regulation of expression of RDR6. Here we report our new findings on the function of OsRDR6 against RDV. Our result showed that down-regulation of OsRDR6 through the antisense (OsRDR6AS) strategy increased rice susceptibility to RDV infection while over-expression of OsRDR6 had no effect on RDV infection. The accumulation of RDV vsiRNAs was reduced in the OsRDR6AS plants. In the OsRDR6 over-expressed plants, the levels of OsRDR6 RNA transcript and protein were much higher than that in the control plants. Interestingly, the accumulation level of OsRDR6 protein became undetectable after RDV infection. This finding indicated that the translation and/or stability of OsRDR6 protein were negatively impacted upon RDV infection. This new finding provides a new light on the function of RDR6 in plant defense response and the cross-talking between factors encoded by host plant and double-stranded RNA viruses.

No MeSH data available.


Related in: MedlinePlus