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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.


Effects of BR levels on the alternative respiratory pathway. N. benthamiana plants were sprayed with 0.01, 0.1, 1, or 5 μM BL solutions while the control plants were sprayed with distilled water or 1 μM BRZ. After pre-treatment for 24h, the sixth leaf of these plants was used for total respiration (Vt) (A), cytochrome respiration (Vcyt) (B), alternative respiration (Valt) (C), Vcyt/Vt (D), Valt/Vt (E), and NbAOX1 expression (F) measurement. 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 1: Effects of BR levels on the alternative respiratory pathway. N. benthamiana plants were sprayed with 0.01, 0.1, 1, or 5 μM BL solutions while the control plants were sprayed with distilled water or 1 μM BRZ. After pre-treatment for 24h, the sixth leaf of these plants was used for total respiration (Vt) (A), cytochrome respiration (Vcyt) (B), alternative respiration (Valt) (C), Vcyt/Vt (D), Valt/Vt (E), and NbAOX1 expression (F) measurement. 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: Total respiration rate (Vt), the capacity of the alternative respiratory pathway (Valt) and cytochrome respiratory pathway (Vcyt) were measured following treatment with water, different concentrations of BL, or BRZ for 24h. The results showed that there was a significant increase in Vt with increasing concentrations of BL treatment as compared with water pre-treated plants (Fig. 1A). Concomitantly, Valt increased dramatically while Vcyt increased slightly in the presence of BL up to 0.1 μM, while a further increase in BL concentration from 0.1 to 5 μM had no significant increasing effects on Valt (Fig. 1B, C). Consequently, the ratio of Valt/Vt increased and peaked at 0.1 μM BL (Fig. 1E), indicating an increased contribution of the alternative respiration pathway to total respiration. In contrast, the ratio of Vcyt/Vt changed little in the presence of BL from 0.01 to 5 μM (Fig. 1D), suggesting small changes in the contribution of cytochrome respiration to total respiration under BL treatment. However, plants pre-treated with BRZ had a decrease in Valt (Fig. 1C). We then analysed the transcript of NbAOX1, which has been shown be highly responsive to growth and stress conditions in N. benthamiana (Lee et al., 2011). Similar to Valt, transcript levels of NbAOX1 were upregulated in BL-treated plants but downregulated in BRZ-treated plants (Fig. 1F). Based on these results, 0.1 μM BL treatment was used in our subsequent experiments.


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)

Effects of BR levels on the alternative respiratory pathway. N. benthamiana plants were sprayed with 0.01, 0.1, 1, or 5 μM BL solutions while the control plants were sprayed with distilled water or 1 μM BRZ. After pre-treatment for 24h, the sixth leaf of these plants was used for total respiration (Vt) (A), cytochrome respiration (Vcyt) (B), alternative respiration (Valt) (C), Vcyt/Vt (D), Valt/Vt (E), and NbAOX1 expression (F) measurement. 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

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4588879&req=5

Figure 1: Effects of BR levels on the alternative respiratory pathway. N. benthamiana plants were sprayed with 0.01, 0.1, 1, or 5 μM BL solutions while the control plants were sprayed with distilled water or 1 μM BRZ. After pre-treatment for 24h, the sixth leaf of these plants was used for total respiration (Vt) (A), cytochrome respiration (Vcyt) (B), alternative respiration (Valt) (C), Vcyt/Vt (D), Valt/Vt (E), and NbAOX1 expression (F) measurement. 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: Total respiration rate (Vt), the capacity of the alternative respiratory pathway (Valt) and cytochrome respiratory pathway (Vcyt) were measured following treatment with water, different concentrations of BL, or BRZ for 24h. The results showed that there was a significant increase in Vt with increasing concentrations of BL treatment as compared with water pre-treated plants (Fig. 1A). Concomitantly, Valt increased dramatically while Vcyt increased slightly in the presence of BL up to 0.1 μM, while a further increase in BL concentration from 0.1 to 5 μM had no significant increasing effects on Valt (Fig. 1B, C). Consequently, the ratio of Valt/Vt increased and peaked at 0.1 μM BL (Fig. 1E), indicating an increased contribution of the alternative respiration pathway to total respiration. In contrast, the ratio of Vcyt/Vt changed little in the presence of BL from 0.01 to 5 μM (Fig. 1D), suggesting small changes in the contribution of cytochrome respiration to total respiration under BL treatment. However, plants pre-treated with BRZ had a decrease in Valt (Fig. 1C). We then analysed the transcript of NbAOX1, which has been shown be highly responsive to growth and stress conditions in N. benthamiana (Lee et al., 2011). Similar to Valt, transcript levels of NbAOX1 were upregulated in BL-treated plants but downregulated in BRZ-treated plants (Fig. 1F). Based on these results, 0.1 μM BL treatment was used in our subsequent experiments.

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.