Limits...
Antimycin A treatment decreases respiratory internal rotenone-insensitive NADH oxidation capacity in potato leaves.

Geisler DA, Johansson FI, Svensson AS, Rasmusson AG - BMC Plant Biol. (2004)

Bottom Line: The internal rotenone-insensitive NADH oxidation decreases after antimycin A treatment of potato leaves.However, the decrease is not due to changes in expression of known nda genes.One consequence of the lower NADH dehydrogenase capacity may be a stabilisation of the respiratory chain reduction level, should the overall capacity of the cytochrome and the alternative pathway be restricted.

View Article: PubMed Central - HTML - PubMed

Affiliation: Dept of Cell and Organism Biology, Lund University, Sölvegatan 35B, Lund, (SE-223 62), Sweden. daniela.geisler@cob.lu.se

ABSTRACT

Background: The plant respiratory chain contains several energy-dissipating enzymes, these being type II NAD(P)H dehydrogenases and the alternative oxidase, not present in mammals. The physiological functions of type II NAD(P)H dehydrogenases are largely unclear and little is known about their responses to stress. In this investigation, potato plants (Solanum tuberosum L., cv. Desiree) were sprayed with antimycin A, an inhibitor of the cytochrome pathway. Enzyme capacities of NAD(P)H dehydrogenases (EC 1.6.5.3) and the alternative oxidase were then analysed in isolated leaf mitochondria.

Results: We report a specific decrease in internal rotenone-insensitive NADH dehydrogenase capacity in mitochondria from antimycin A-treated leaves. External NADPH dehydrogenase and alternative oxidase capacities remained unaffected by the treatment. Western blotting revealed no change in protein abundance for two characterised NAD(P)H dehydrogenase homologues, NDA1 and NDB1, nor for two subunits of complex I. The alternative oxidase was at most only slightly increased. Transcript levels of nda1, as well as an expressed sequence tag derived from a previously uninvestigated closely related potato homologue, remained unchanged by the treatment. As compared to the daily rhythm-regulated nda1, the novel homologue displayed steady transcript levels over the time investigated.

Conclusions: The internal rotenone-insensitive NADH oxidation decreases after antimycin A treatment of potato leaves. However, the decrease is not due to changes in expression of known nda genes. One consequence of the lower NADH dehydrogenase capacity may be a stabilisation of the respiratory chain reduction level, should the overall capacity of the cytochrome and the alternative pathway be restricted.

Show MeSH
Transcript quantification by real-time PCR in control and antimycin A-treated potato leaves. Potato plants were sprayed at 03:00 h, one hour before light, and leaf samples were collected at start of the treatment (03:00 h), after 4 h (at 07:00 h) and after 8 h (at 11:00 h). White columns, leaves sprayed with solvent only. Black columns, leaves sprayed with 10 μM antimycin A. Transcript abundance is shown for nda1 (A), TC54504 (B) and the 28.5 kDa subunit of complex I (C). Transcript levels are given as percent of the level in the control plants at the start of the treatment (03:00 h). The error bars indicate standard deviation (n = 2).
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC424582&req=5

Figure 5: Transcript quantification by real-time PCR in control and antimycin A-treated potato leaves. Potato plants were sprayed at 03:00 h, one hour before light, and leaf samples were collected at start of the treatment (03:00 h), after 4 h (at 07:00 h) and after 8 h (at 11:00 h). White columns, leaves sprayed with solvent only. Black columns, leaves sprayed with 10 μM antimycin A. Transcript abundance is shown for nda1 (A), TC54504 (B) and the 28.5 kDa subunit of complex I (C). Transcript levels are given as percent of the level in the control plants at the start of the treatment (03:00 h). The error bars indicate standard deviation (n = 2).

Mentions: Since antibodies may vary in detecting different isoenzymes, gene expression of nda1 was additionally analysed at transcript level using a real-time PCR system. Plants were sprayed 1 h before light onset (03:00 h) and leaf transcript levels for nda1 were quantified at the time of treatment (03:00 h), after 4 h (07:00 h) and 8 h (11:00 h). Antimycin A treatment affected neither the level of nda1 transcripts nor its diurnal change in expression during this part of the day (Fig. 5A). The transcript for the 28.5 kDa subunit of complex I was similar in all isolates (Fig. 5C). In a separate experiment, total RNA was isolated from the same leaf material that was used for mitochondrial purification. No appreciable changes were seen in nda1 transcript amounts 24 h after spraying with 0, 3, 10 and 30 μM antimycin A (data not shown).


Antimycin A treatment decreases respiratory internal rotenone-insensitive NADH oxidation capacity in potato leaves.

Geisler DA, Johansson FI, Svensson AS, Rasmusson AG - BMC Plant Biol. (2004)

Transcript quantification by real-time PCR in control and antimycin A-treated potato leaves. Potato plants were sprayed at 03:00 h, one hour before light, and leaf samples were collected at start of the treatment (03:00 h), after 4 h (at 07:00 h) and after 8 h (at 11:00 h). White columns, leaves sprayed with solvent only. Black columns, leaves sprayed with 10 μM antimycin A. Transcript abundance is shown for nda1 (A), TC54504 (B) and the 28.5 kDa subunit of complex I (C). Transcript levels are given as percent of the level in the control plants at the start of the treatment (03:00 h). The error bars indicate standard deviation (n = 2).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC424582&req=5

Figure 5: Transcript quantification by real-time PCR in control and antimycin A-treated potato leaves. Potato plants were sprayed at 03:00 h, one hour before light, and leaf samples were collected at start of the treatment (03:00 h), after 4 h (at 07:00 h) and after 8 h (at 11:00 h). White columns, leaves sprayed with solvent only. Black columns, leaves sprayed with 10 μM antimycin A. Transcript abundance is shown for nda1 (A), TC54504 (B) and the 28.5 kDa subunit of complex I (C). Transcript levels are given as percent of the level in the control plants at the start of the treatment (03:00 h). The error bars indicate standard deviation (n = 2).
Mentions: Since antibodies may vary in detecting different isoenzymes, gene expression of nda1 was additionally analysed at transcript level using a real-time PCR system. Plants were sprayed 1 h before light onset (03:00 h) and leaf transcript levels for nda1 were quantified at the time of treatment (03:00 h), after 4 h (07:00 h) and 8 h (11:00 h). Antimycin A treatment affected neither the level of nda1 transcripts nor its diurnal change in expression during this part of the day (Fig. 5A). The transcript for the 28.5 kDa subunit of complex I was similar in all isolates (Fig. 5C). In a separate experiment, total RNA was isolated from the same leaf material that was used for mitochondrial purification. No appreciable changes were seen in nda1 transcript amounts 24 h after spraying with 0, 3, 10 and 30 μM antimycin A (data not shown).

Bottom Line: The internal rotenone-insensitive NADH oxidation decreases after antimycin A treatment of potato leaves.However, the decrease is not due to changes in expression of known nda genes.One consequence of the lower NADH dehydrogenase capacity may be a stabilisation of the respiratory chain reduction level, should the overall capacity of the cytochrome and the alternative pathway be restricted.

View Article: PubMed Central - HTML - PubMed

Affiliation: Dept of Cell and Organism Biology, Lund University, Sölvegatan 35B, Lund, (SE-223 62), Sweden. daniela.geisler@cob.lu.se

ABSTRACT

Background: The plant respiratory chain contains several energy-dissipating enzymes, these being type II NAD(P)H dehydrogenases and the alternative oxidase, not present in mammals. The physiological functions of type II NAD(P)H dehydrogenases are largely unclear and little is known about their responses to stress. In this investigation, potato plants (Solanum tuberosum L., cv. Desiree) were sprayed with antimycin A, an inhibitor of the cytochrome pathway. Enzyme capacities of NAD(P)H dehydrogenases (EC 1.6.5.3) and the alternative oxidase were then analysed in isolated leaf mitochondria.

Results: We report a specific decrease in internal rotenone-insensitive NADH dehydrogenase capacity in mitochondria from antimycin A-treated leaves. External NADPH dehydrogenase and alternative oxidase capacities remained unaffected by the treatment. Western blotting revealed no change in protein abundance for two characterised NAD(P)H dehydrogenase homologues, NDA1 and NDB1, nor for two subunits of complex I. The alternative oxidase was at most only slightly increased. Transcript levels of nda1, as well as an expressed sequence tag derived from a previously uninvestigated closely related potato homologue, remained unchanged by the treatment. As compared to the daily rhythm-regulated nda1, the novel homologue displayed steady transcript levels over the time investigated.

Conclusions: The internal rotenone-insensitive NADH oxidation decreases after antimycin A treatment of potato leaves. However, the decrease is not due to changes in expression of known nda genes. One consequence of the lower NADH dehydrogenase capacity may be a stabilisation of the respiratory chain reduction level, should the overall capacity of the cytochrome and the alternative pathway be restricted.

Show MeSH