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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

Over-expression of OsRDR6 did not affect RDV infection in rice.(a) Western blot analysis of OsRDR6 protein expression in the OsRDR6-over-expression (OsRDR6 OE), empty vector transformed (EV) and the WT rice plants. Rice Hsp90 was served as the loading control. (b) Comparison of RDV infected phenotypes in the OsRDR6 OE, EV and WT plants. The OsRDR6 OE rice plants did not show reduced disease symptoms comparable with the control plants. (c) The infection rates of the OsRDR6 OE, EV and WT plants at various wpi. The infection rate was determined using 30 individual plants per treatment at each wpi. Inoculation assay was repeated three times. The error bars indicate the standard errors. P > 0.05 (Student’s t test). (d) Northern blot assay of RDV S2 and S11 genomic RNA accumulation in the OsRDR6 OE, EV and WT plants. Thirty plants showing disease symptoms were harvested from each treatment at 3 wpi for total RNA isolation. (e) Northern blot assay for RDV siRNAs accumulation in the OsRDR6 OE, EV and WT plants. The plant samples used in (d) were used for this analysis. U6 RNA was used as the loading control.
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f3: Over-expression of OsRDR6 did not affect RDV infection in rice.(a) Western blot analysis of OsRDR6 protein expression in the OsRDR6-over-expression (OsRDR6 OE), empty vector transformed (EV) and the WT rice plants. Rice Hsp90 was served as the loading control. (b) Comparison of RDV infected phenotypes in the OsRDR6 OE, EV and WT plants. The OsRDR6 OE rice plants did not show reduced disease symptoms comparable with the control plants. (c) The infection rates of the OsRDR6 OE, EV and WT plants at various wpi. The infection rate was determined using 30 individual plants per treatment at each wpi. Inoculation assay was repeated three times. The error bars indicate the standard errors. P > 0.05 (Student’s t test). (d) Northern blot assay of RDV S2 and S11 genomic RNA accumulation in the OsRDR6 OE, EV and WT plants. Thirty plants showing disease symptoms were harvested from each treatment at 3 wpi for total RNA isolation. (e) Northern blot assay for RDV siRNAs accumulation in the OsRDR6 OE, EV and WT plants. The plant samples used in (d) were used for this analysis. U6 RNA was used as the loading control.

Mentions: Because silencing OsRDR6 expression in rice resulted in an increased RDV accumulation and stronger disease symptoms in the RDV-infected rice plants, we reasoned that over-expression of OsRDR6 would cause an increased resistance against RDV. To test this hypothesis we generated OsRDR6-over-expressing transgenic rice lines and inoculated them with RDV. Figure S2 showed that transgenic line 1, 2, 6, 23 and 24 contained a single-copy of OsRDR6 transgene while line 9 has two copies (Fig. S2). Western blot showed that all the over-expression (OE) transgenic lines produced high levels of OsRDR6 proteins while this protein in the WT or the empty vector (EV) transformed control rice plants was not detectable with this method (Fig. 3a). Growth of all the OsRDR6 OE lines were comparable to the WT and EV control plants (Fig. 3b top panel). Surprisingly, none of the OsRDR6 OE rice lines showed an increased resistance to RDV infection comparable with the WT and EV control plants (Fig. 3b). In addition, the infection rates of all the RDV-inoculated OsRDR6 OE lines were similar to that of the WT and EV control plants (Fig. 3c).


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)

Over-expression of OsRDR6 did not affect RDV infection in rice.(a) Western blot analysis of OsRDR6 protein expression in the OsRDR6-over-expression (OsRDR6 OE), empty vector transformed (EV) and the WT rice plants. Rice Hsp90 was served as the loading control. (b) Comparison of RDV infected phenotypes in the OsRDR6 OE, EV and WT plants. The OsRDR6 OE rice plants did not show reduced disease symptoms comparable with the control plants. (c) The infection rates of the OsRDR6 OE, EV and WT plants at various wpi. The infection rate was determined using 30 individual plants per treatment at each wpi. Inoculation assay was repeated three times. The error bars indicate the standard errors. P > 0.05 (Student’s t test). (d) Northern blot assay of RDV S2 and S11 genomic RNA accumulation in the OsRDR6 OE, EV and WT plants. Thirty plants showing disease symptoms were harvested from each treatment at 3 wpi for total RNA isolation. (e) Northern blot assay for RDV siRNAs accumulation in the OsRDR6 OE, EV and WT plants. The plant samples used in (d) were used for this analysis. U6 RNA was used as the loading control.
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Related In: Results  -  Collection

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f3: Over-expression of OsRDR6 did not affect RDV infection in rice.(a) Western blot analysis of OsRDR6 protein expression in the OsRDR6-over-expression (OsRDR6 OE), empty vector transformed (EV) and the WT rice plants. Rice Hsp90 was served as the loading control. (b) Comparison of RDV infected phenotypes in the OsRDR6 OE, EV and WT plants. The OsRDR6 OE rice plants did not show reduced disease symptoms comparable with the control plants. (c) The infection rates of the OsRDR6 OE, EV and WT plants at various wpi. The infection rate was determined using 30 individual plants per treatment at each wpi. Inoculation assay was repeated three times. The error bars indicate the standard errors. P > 0.05 (Student’s t test). (d) Northern blot assay of RDV S2 and S11 genomic RNA accumulation in the OsRDR6 OE, EV and WT plants. Thirty plants showing disease symptoms were harvested from each treatment at 3 wpi for total RNA isolation. (e) Northern blot assay for RDV siRNAs accumulation in the OsRDR6 OE, EV and WT plants. The plant samples used in (d) were used for this analysis. U6 RNA was used as the loading control.
Mentions: Because silencing OsRDR6 expression in rice resulted in an increased RDV accumulation and stronger disease symptoms in the RDV-infected rice plants, we reasoned that over-expression of OsRDR6 would cause an increased resistance against RDV. To test this hypothesis we generated OsRDR6-over-expressing transgenic rice lines and inoculated them with RDV. Figure S2 showed that transgenic line 1, 2, 6, 23 and 24 contained a single-copy of OsRDR6 transgene while line 9 has two copies (Fig. S2). Western blot showed that all the over-expression (OE) transgenic lines produced high levels of OsRDR6 proteins while this protein in the WT or the empty vector (EV) transformed control rice plants was not detectable with this method (Fig. 3a). Growth of all the OsRDR6 OE lines were comparable to the WT and EV control plants (Fig. 3b top panel). Surprisingly, none of the OsRDR6 OE rice lines showed an increased resistance to RDV infection comparable with the WT and EV control plants (Fig. 3b). In addition, the infection rates of all the RDV-inoculated OsRDR6 OE lines were similar to that of the WT and EV control plants (Fig. 3c).

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