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An Arabidopsis mitochondria-localized RRL protein mediates abscisic acid signal transduction through mitochondrial retrograde regulation involving ABI4.

Yao X, Li J, Liu J, Liu K - J. Exp. Bot. (2015)

Bottom Line: High expression levels of RRL were found in germinating seeds and developing seedlings, as revealed by β-glucuronidase (GUS) staining of ProRRL-GUS transgenic lines.The analyses of the structure and function of mitochondria in the knockout rrl mutant showed that the disruption of RRL causes extensively internally vacuolated mitochondria and reduced ABA-stimulated reactive oxygen species (ROS) production.Furthermore, the results revealed that ABI4 is a downstream regulatory factor in RRL-mediated ABA signalling in seed germination and seedling growth.

View Article: PubMed Central - PubMed

Affiliation: National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China.

No MeSH data available.


Related in: MedlinePlus

Structure and numbers of mitochondria and ABA-induced ROS production in the rrl mutant. (A–D) The mitochondrial structure in Col-0 (A) and the rrl mutant (B) was observed by transmission electron microscopy. (C, D) Magnification of the areas outlined in (A, B). Arrows indicate mitochondria. Scale bar=0.5 μm (A, B); 0.25 μm (C, D). (E) Numbers of mitochondria per square micrometre in 5-day-old seedlings of Col-0 and the rrl mutant were determined. Values are the means ±SD from three independent measurements. (F) ROS production was detected with the fluorescent dye DCF. Five-day-old seedlings were incubated with 2′,7′-dichlorodihydrofluorescein diacetate (H2DCFDA) for 30min. –ABA, ABA-free treatment; +ABA, 50 μM ABA treatment. Scale bar=20 μm. (G) Quantification of ROS levels in Col-0 and the rrl mutant before or after 50 μM ABA treatment. (n=30; ±SD; *P<0.001 compared with ABA-treated Col-0 plants). The fluorescent intensity in Col-0 with ABA treatment was taken as 100%.(This figure is available in colour at JXB online.)
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Figure 5: Structure and numbers of mitochondria and ABA-induced ROS production in the rrl mutant. (A–D) The mitochondrial structure in Col-0 (A) and the rrl mutant (B) was observed by transmission electron microscopy. (C, D) Magnification of the areas outlined in (A, B). Arrows indicate mitochondria. Scale bar=0.5 μm (A, B); 0.25 μm (C, D). (E) Numbers of mitochondria per square micrometre in 5-day-old seedlings of Col-0 and the rrl mutant were determined. Values are the means ±SD from three independent measurements. (F) ROS production was detected with the fluorescent dye DCF. Five-day-old seedlings were incubated with 2′,7′-dichlorodihydrofluorescein diacetate (H2DCFDA) for 30min. –ABA, ABA-free treatment; +ABA, 50 μM ABA treatment. Scale bar=20 μm. (G) Quantification of ROS levels in Col-0 and the rrl mutant before or after 50 μM ABA treatment. (n=30; ±SD; *P<0.001 compared with ABA-treated Col-0 plants). The fluorescent intensity in Col-0 with ABA treatment was taken as 100%.(This figure is available in colour at JXB online.)

Mentions: As shown in Fig. 1, RRL is a mitochondria-localized protein in Arabidopsis. Next it was examined whether the disruption of the RRL gene affects the number and structure of mitochondria. Transmission electron microscopy was used to observe the mitochondria in 5-day-old seedling roots of Col-0 and the rrl mutant. A total of 76% of mitochondria in mutant cells exhibited extensive internal vacuolization compared with Col-0 (Fig. 5A–D), but the number of mitochondria per unit of cell area in mutant rrl (0.50mm–2) was found to be the same as that of Col-0 (0.48mm–2) (Fig. 5E). These results suggest that the disruption of the RRL gene results in aberrant mitochondrial structure, but does not affect the number of mitochondria (Fig. 5A–E).


An Arabidopsis mitochondria-localized RRL protein mediates abscisic acid signal transduction through mitochondrial retrograde regulation involving ABI4.

Yao X, Li J, Liu J, Liu K - J. Exp. Bot. (2015)

Structure and numbers of mitochondria and ABA-induced ROS production in the rrl mutant. (A–D) The mitochondrial structure in Col-0 (A) and the rrl mutant (B) was observed by transmission electron microscopy. (C, D) Magnification of the areas outlined in (A, B). Arrows indicate mitochondria. Scale bar=0.5 μm (A, B); 0.25 μm (C, D). (E) Numbers of mitochondria per square micrometre in 5-day-old seedlings of Col-0 and the rrl mutant were determined. Values are the means ±SD from three independent measurements. (F) ROS production was detected with the fluorescent dye DCF. Five-day-old seedlings were incubated with 2′,7′-dichlorodihydrofluorescein diacetate (H2DCFDA) for 30min. –ABA, ABA-free treatment; +ABA, 50 μM ABA treatment. Scale bar=20 μm. (G) Quantification of ROS levels in Col-0 and the rrl mutant before or after 50 μM ABA treatment. (n=30; ±SD; *P<0.001 compared with ABA-treated Col-0 plants). The fluorescent intensity in Col-0 with ABA treatment was taken as 100%.(This figure is available in colour at JXB online.)
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Related In: Results  -  Collection

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Figure 5: Structure and numbers of mitochondria and ABA-induced ROS production in the rrl mutant. (A–D) The mitochondrial structure in Col-0 (A) and the rrl mutant (B) was observed by transmission electron microscopy. (C, D) Magnification of the areas outlined in (A, B). Arrows indicate mitochondria. Scale bar=0.5 μm (A, B); 0.25 μm (C, D). (E) Numbers of mitochondria per square micrometre in 5-day-old seedlings of Col-0 and the rrl mutant were determined. Values are the means ±SD from three independent measurements. (F) ROS production was detected with the fluorescent dye DCF. Five-day-old seedlings were incubated with 2′,7′-dichlorodihydrofluorescein diacetate (H2DCFDA) for 30min. –ABA, ABA-free treatment; +ABA, 50 μM ABA treatment. Scale bar=20 μm. (G) Quantification of ROS levels in Col-0 and the rrl mutant before or after 50 μM ABA treatment. (n=30; ±SD; *P<0.001 compared with ABA-treated Col-0 plants). The fluorescent intensity in Col-0 with ABA treatment was taken as 100%.(This figure is available in colour at JXB online.)
Mentions: As shown in Fig. 1, RRL is a mitochondria-localized protein in Arabidopsis. Next it was examined whether the disruption of the RRL gene affects the number and structure of mitochondria. Transmission electron microscopy was used to observe the mitochondria in 5-day-old seedling roots of Col-0 and the rrl mutant. A total of 76% of mitochondria in mutant cells exhibited extensive internal vacuolization compared with Col-0 (Fig. 5A–D), but the number of mitochondria per unit of cell area in mutant rrl (0.50mm–2) was found to be the same as that of Col-0 (0.48mm–2) (Fig. 5E). These results suggest that the disruption of the RRL gene results in aberrant mitochondrial structure, but does not affect the number of mitochondria (Fig. 5A–E).

Bottom Line: High expression levels of RRL were found in germinating seeds and developing seedlings, as revealed by β-glucuronidase (GUS) staining of ProRRL-GUS transgenic lines.The analyses of the structure and function of mitochondria in the knockout rrl mutant showed that the disruption of RRL causes extensively internally vacuolated mitochondria and reduced ABA-stimulated reactive oxygen species (ROS) production.Furthermore, the results revealed that ABI4 is a downstream regulatory factor in RRL-mediated ABA signalling in seed germination and seedling growth.

View Article: PubMed Central - PubMed

Affiliation: National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China.

No MeSH data available.


Related in: MedlinePlus