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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

RDV-infected OsRDR6AS rice plants exhibited more severe stunting than the RDV-infected wild type (WT) Zhonghua11 plants.(a) Phenotypes of the RDV-infected OsRDR6AS and WT Zhonghua11 plants at 3 weeks post RDV inoculation (wpi). (b) Time course study of infection rate for RDV-inoculated OsRDR6AS and WT plants. The visual disease symptoms were assessed with 30 individual plants per treatment. * P < 0.05; ** P < 0.01 (Student’s t test). The inoculation assay was repeated three times. The error bars indicate the standard errors.
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f1: RDV-infected OsRDR6AS rice plants exhibited more severe stunting than the RDV-infected wild type (WT) Zhonghua11 plants.(a) Phenotypes of the RDV-infected OsRDR6AS and WT Zhonghua11 plants at 3 weeks post RDV inoculation (wpi). (b) Time course study of infection rate for RDV-inoculated OsRDR6AS and WT plants. The visual disease symptoms were assessed with 30 individual plants per treatment. * P < 0.05; ** P < 0.01 (Student’s t test). The inoculation assay was repeated three times. The error bars indicate the standard errors.

Mentions: Our previous study showed that RDV infection in rice reduced OsRDR6 expression41. We also reported in a separate study that OsRDR6AS transgenic rice plants accumulated significantly less amount of OsRDR6 RNA transcripts and were more susceptible to RSV (a single-stranded RNA virus) infection33. In this study, the OsRDR6AS transgenic rice lines were inoculated with RDV via viruliferous leafhopper. By three weeks post virus inoculation (wpi), the RDV-inoculated OsRDR6AS plants exhibited more severe stunting phenotypes (Fig. 1a) than those shown by the RDV-inoculated wild type (WT) rice plants. The infection rates of RDV in the OsRDR6AS transgenic lines were also higher than those in the WT rice plants at various wpi (Fig. 1b). Plants of OsRDR6AS transgenic line B and C showed RDV symptoms as early as 1wpi (Fig. 1b). By 7wpi, the RDV infection rate in the three OsRDR6AS transgenic lines reached above 90% while the infection rate of the WT plants was about 80%, indicating that down-regulation of OsRDR6 expression in rice increased the susceptibility to RDV infection.


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)

RDV-infected OsRDR6AS rice plants exhibited more severe stunting than the RDV-infected wild type (WT) Zhonghua11 plants.(a) Phenotypes of the RDV-infected OsRDR6AS and WT Zhonghua11 plants at 3 weeks post RDV inoculation (wpi). (b) Time course study of infection rate for RDV-inoculated OsRDR6AS and WT plants. The visual disease symptoms were assessed with 30 individual plants per treatment. * P < 0.05; ** P < 0.01 (Student’s t test). The inoculation assay was repeated three times. The error bars indicate the standard errors.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f1: RDV-infected OsRDR6AS rice plants exhibited more severe stunting than the RDV-infected wild type (WT) Zhonghua11 plants.(a) Phenotypes of the RDV-infected OsRDR6AS and WT Zhonghua11 plants at 3 weeks post RDV inoculation (wpi). (b) Time course study of infection rate for RDV-inoculated OsRDR6AS and WT plants. The visual disease symptoms were assessed with 30 individual plants per treatment. * P < 0.05; ** P < 0.01 (Student’s t test). The inoculation assay was repeated three times. The error bars indicate the standard errors.
Mentions: Our previous study showed that RDV infection in rice reduced OsRDR6 expression41. We also reported in a separate study that OsRDR6AS transgenic rice plants accumulated significantly less amount of OsRDR6 RNA transcripts and were more susceptible to RSV (a single-stranded RNA virus) infection33. In this study, the OsRDR6AS transgenic rice lines were inoculated with RDV via viruliferous leafhopper. By three weeks post virus inoculation (wpi), the RDV-inoculated OsRDR6AS plants exhibited more severe stunting phenotypes (Fig. 1a) than those shown by the RDV-inoculated wild type (WT) rice plants. The infection rates of RDV in the OsRDR6AS transgenic lines were also higher than those in the WT rice plants at various wpi (Fig. 1b). Plants of OsRDR6AS transgenic line B and C showed RDV symptoms as early as 1wpi (Fig. 1b). By 7wpi, the RDV infection rate in the three OsRDR6AS transgenic lines reached above 90% while the infection rate of the WT plants was about 80%, indicating that down-regulation of OsRDR6 expression in rice increased the susceptibility to RDV infection.

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