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The alternative respiratory pathway is involved in brassinosteroid-induced environmental stress tolerance in Nicotiana benthamiana.

Deng XG, Zhu T, Zhang DW, Lin HH - J. Exp. Bot. (2015)

Bottom Line: Chemical scavenging of H2O2 and virus-induced gene silencing (VIGS) of NbRBOHB compromised the BR-induced alternative respiratory pathway, and this result was further confirmed by NbAOX1 promoter analysis.Furthermore, inhibition of AOX activity by chemical treatment or a VIGS-based approach decreased plant resistance to environmental stresses and compromised BR-induced stress tolerance.Taken together, our results indicate that BR-induced AOX capability might contribute to the avoidance of superfluous reactive oxygen species accumulation and the protection of photosystems under stress conditions in N. benthamiana.

View Article: PubMed Central - PubMed

Affiliation: Ministry of Education Key Laboratory for Bio-Resource and Eco-Environment, College of Life Science, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, 610064, PR China Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, PR China.

No MeSH data available.


Involvement of H2O2 in the BR-induced alternative respiratory pathway. (A, B) Changes of alternative respiration (Valt) (A) and NbAOX1 expression (B) in H2O2 scavenger DMTU pre-treated plants as influenced by 0.1 μM BL. N. benthamiana plants were treated with 5mM DMTU for 8h and then treated with 0.1 μM BL for another 24h. Single treatment of BL or DMTU was included as a control. (C, D) Changes in alternative respiration (C) and NbAOX1 expression (D) in NbRBOHB-silenced plants as influenced by 0.1 μM BL. Bars represent mean and standard deviation of values obtained from three biological repeats. Significant differences (P<0.05) are denoted by different lowercase letters. FW, fresh weight.
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Figure 3: Involvement of H2O2 in the BR-induced alternative respiratory pathway. (A, B) Changes of alternative respiration (Valt) (A) and NbAOX1 expression (B) in H2O2 scavenger DMTU pre-treated plants as influenced by 0.1 μM BL. N. benthamiana plants were treated with 5mM DMTU for 8h and then treated with 0.1 μM BL for another 24h. Single treatment of BL or DMTU was included as a control. (C, D) Changes in alternative respiration (C) and NbAOX1 expression (D) in NbRBOHB-silenced plants as influenced by 0.1 μM BL. Bars represent mean and standard deviation of values obtained from three biological repeats. Significant differences (P<0.05) are denoted by different lowercase letters. FW, fresh weight.

Mentions: To further investigate the effects of BR-induced H2O2 production on the BR-induced alternative respiratory pathway, N. benthamiana leaves were pre-treated with DMTU, an ROS scavenger, and then exposed to BL treatment. Pre-treatment with DMTU substantially reduced the BR-induced increases in Valt and NbAOX1 expression, whereas the single DMTU treatment had little effect on Valt and NbAOX1 expression when compared with water-treated plants (Fig. 3A, B). To further elucidate the role of NADPH oxidase (RBOH) genes in the regulation of the alternative pathway in BR signalling, we knocked down NbRBOHA and NbRBOHB using a TRV-based VIGS system in N. benthamiana. The downregulation of NbRBOHA and NbRBOHB in silenced plants was confirmed by real-time PCR after 12 d of infiltration (Supplementary Fig. S2, available at JXB online). Similar to DMTU treatment, BR-induced Valt and NbAOX1 expression were compromised in NbRBOHB-silenced plants in comparison with the control (TRV:00) (Fig. 3C, D) or NbRBOHA-silenced plants (Supplementary Fig. S3, available at JXB online). These results suggested that RBOHB-dependent H2O2 accumulation is required for the BR-induced alternative respiratory pathway.


The alternative respiratory pathway is involved in brassinosteroid-induced environmental stress tolerance in Nicotiana benthamiana.

Deng XG, Zhu T, Zhang DW, Lin HH - J. Exp. Bot. (2015)

Involvement of H2O2 in the BR-induced alternative respiratory pathway. (A, B) Changes of alternative respiration (Valt) (A) and NbAOX1 expression (B) in H2O2 scavenger DMTU pre-treated plants as influenced by 0.1 μM BL. N. benthamiana plants were treated with 5mM DMTU for 8h and then treated with 0.1 μM BL for another 24h. Single treatment of BL or DMTU was included as a control. (C, D) Changes in alternative respiration (C) and NbAOX1 expression (D) in NbRBOHB-silenced plants as influenced by 0.1 μM BL. Bars represent mean and standard deviation of values obtained from three biological repeats. Significant differences (P<0.05) are denoted by different lowercase letters. FW, fresh weight.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

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Figure 3: Involvement of H2O2 in the BR-induced alternative respiratory pathway. (A, B) Changes of alternative respiration (Valt) (A) and NbAOX1 expression (B) in H2O2 scavenger DMTU pre-treated plants as influenced by 0.1 μM BL. N. benthamiana plants were treated with 5mM DMTU for 8h and then treated with 0.1 μM BL for another 24h. Single treatment of BL or DMTU was included as a control. (C, D) Changes in alternative respiration (C) and NbAOX1 expression (D) in NbRBOHB-silenced plants as influenced by 0.1 μM BL. Bars represent mean and standard deviation of values obtained from three biological repeats. Significant differences (P<0.05) are denoted by different lowercase letters. FW, fresh weight.
Mentions: To further investigate the effects of BR-induced H2O2 production on the BR-induced alternative respiratory pathway, N. benthamiana leaves were pre-treated with DMTU, an ROS scavenger, and then exposed to BL treatment. Pre-treatment with DMTU substantially reduced the BR-induced increases in Valt and NbAOX1 expression, whereas the single DMTU treatment had little effect on Valt and NbAOX1 expression when compared with water-treated plants (Fig. 3A, B). To further elucidate the role of NADPH oxidase (RBOH) genes in the regulation of the alternative pathway in BR signalling, we knocked down NbRBOHA and NbRBOHB using a TRV-based VIGS system in N. benthamiana. The downregulation of NbRBOHA and NbRBOHB in silenced plants was confirmed by real-time PCR after 12 d of infiltration (Supplementary Fig. S2, available at JXB online). Similar to DMTU treatment, BR-induced Valt and NbAOX1 expression were compromised in NbRBOHB-silenced plants in comparison with the control (TRV:00) (Fig. 3C, D) or NbRBOHA-silenced plants (Supplementary Fig. S3, available at JXB online). These results suggested that RBOHB-dependent H2O2 accumulation is required for the BR-induced alternative respiratory pathway.

Bottom Line: Chemical scavenging of H2O2 and virus-induced gene silencing (VIGS) of NbRBOHB compromised the BR-induced alternative respiratory pathway, and this result was further confirmed by NbAOX1 promoter analysis.Furthermore, inhibition of AOX activity by chemical treatment or a VIGS-based approach decreased plant resistance to environmental stresses and compromised BR-induced stress tolerance.Taken together, our results indicate that BR-induced AOX capability might contribute to the avoidance of superfluous reactive oxygen species accumulation and the protection of photosystems under stress conditions in N. benthamiana.

View Article: PubMed Central - PubMed

Affiliation: Ministry of Education Key Laboratory for Bio-Resource and Eco-Environment, College of Life Science, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, 610064, PR China Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, PR China.

No MeSH data available.