Abstract
To investigate the role of plant mitochondria in drought tolerance, the response to water deprivation was compared between Nicotiana sylvestris wild type (WT) plants and the CMSII respiratory complex I mutant, which has low-efficient respiration and photosynthesis, high lev- els of amino acids and pyridine nucleotides, and increased antioxidant capacity. We show that the delayed decrease in relative water content after water withholding in CMSII, as compared to WT leaves, is due to a lower stomatal con- ductance. The stomatal index and the abscisic acid (ABA) content were unaffected in well-watered mutant leaves, but the ABA/stomatal conductance relation was altered during drought, indicating that specific factors interact with ABA signalling. Leaf hydraulic conductance was lower in mutant leaves when compared to WT leaves and the role of oxidative aquaporin gating in attaining a maximum sto- matal conductance is discussed. In addition, differences in leaf metabolic status between the mutant and the WT might contribute to the low stomatal conductance, as reported for TCA cycle-deficient plants. After withholding watering, TCA cycle derived organic acids declined more in CMSII leaves than in the WT, and ATP content decreased only in the CMSII. Moreover, in contrast to the WT, total free amino acid levels declined whilst soluble protein content increased in CMSII leaves, suggesting an accelerated amino acid remobilisation. We propose that oxidative and metabolic disturbances resulting from remodelled respira- tion in the absence of Complex I activity could be involved in bringing about the lower stomatal and hydraulic conductances.
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Claims 11
Claim · model-written summary
CMSII had a delayed fall in relative water content after water withholding.
- Taxon
- Nicotiana sylvestris
.jpg?width=60)
Nicotiana sylvestrise7 - Material
- CMSIIe0
- Outcome
- relative water contente0
- Direction
- delayed decreasee0
- Comparator
- WT leavese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“delayed decrease in relative water content after water withholding in CMSII, as compared to WT leaves”
e7“Nicotiana sylvestris wild type (WT) plants”
Claim · model-written summary
CMSII had lower stomatal conductance than wild type under water withholding.
- Taxon
- Nicotiana sylvestrisNicotiana sylvestrise7
- Material
- CMSIIe0
- Outcome
- stomatal con- ductancee0
- Direction
- lowere0
- Comparator
- WT leavese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“delayed decrease in relative water content after water withholding in CMSII, as compared to WT leaves, is due to a lower stomatal con- ductance”
e7“Nicotiana sylvestris wild type (WT) plants”
Claim · model-written summary
Well-watered CMSII leaves had unaffected stomatal index.
- Taxon
- Nicotiana sylvestrisNicotiana sylvestrise7
- Material
- mutante0
- Organ / stage
- leavese0
- Outcome
- stomatal indexe0
- Direction
- unaffectede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The stomatal index and the abscisic acid (ABA) content were unaffected in well-watered mutant leaves”
e7“Nicotiana sylvestris wild type (WT) plants”
Claim · model-written summary
Well-watered CMSII leaves had unaffected ABA content.
- Taxon
- Nicotiana sylvestrisNicotiana sylvestrise7
- Material
- mutante0
- Outcome
- abscisic acid (ABA) contente0
- Direction
- unaffectede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The stomatal index and the abscisic acid (ABA) content were unaffected in well-watered mutant leaves”
e7“Nicotiana sylvestris wild type (WT) plants”
Claim · model-written summary
The relation between ABA and stomatal conductance was altered during drought.
- Taxon
- Nicotiana sylvestrisNicotiana sylvestrise7
- Compound
- ABAe0
- Outcome
- stomatal conductance relatione0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the ABA/stomatal conductance relation was altered during drought”
e7“Nicotiana sylvestris wild type (WT) plants”
Claim · model-written summary
CMSII leaf hydraulic conductance was lower than wild type.
- Taxon
- Nicotiana sylvestrisNicotiana sylvestrise7
- Material
- mutante0
- Outcome
- Leaf hydraulic conductancee0
- Direction
- lowere0
- Comparator
- WT leavese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Leaf hydraulic conductance was lower in mutant leaves when compared to WT leaves”
e7“Nicotiana sylvestris wild type (WT) plants”
Claim · model-written summary
TCA-derived organic acids declined more in CMSII leaves than wild type after withholding water.
- Taxon
- Nicotiana sylvestrisNicotiana sylvestrise7
- Material
- CMSIIe0
- Outcome
- TCA cycle derived organic acidse0
- Direction
- declined moree0
- Comparator
- WTe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“After withholding watering, TCA cycle derived organic acids declined more in CMSII leaves than in the WT”
e7“Nicotiana sylvestris wild type (WT) plants”
Claim · model-written summary
ATP content decreased only in CMSII after withholding water.
- Taxon
- Nicotiana sylvestrisNicotiana sylvestrise7
- Material
- CMSIIe0
- Outcome
- ATP contente0
- Direction
- decreasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“ATP content decreased only in the CMSII”
e7“Nicotiana sylvestris wild type (WT) plants”
Claim · model-written summary
Free amino acid levels declined in CMSII unlike wild type.
- Taxon
- Nicotiana sylvestrisNicotiana sylvestrise7
- Material
- CMSIIe0
- Outcome
- total free amino acid levelse0
- Direction
- declinede0
- Comparator
- WTe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in contrast to the WT, total free amino acid levels declined whilst soluble protein content increased in CMSII leaves”
e7“Nicotiana sylvestris wild type (WT) plants”
Claim · model-written summary
Soluble protein content increased in CMSII unlike wild type.
- Taxon
- Nicotiana sylvestrisNicotiana sylvestrise7
- Material
- CMSIIe0
- Outcome
- soluble protein contente0
- Direction
- increasede0
- Comparator
- WTe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in contrast to the WT, total free amino acid levels declined whilst soluble protein content increased in CMSII leaves”
e7“Nicotiana sylvestris wild type (WT) plants”
Claim · model-written summary
The authors propose that respiratory oxidative and metabolic disturbances may cause lower stomatal conductance.
- Taxon
- Nicotiana sylvestrisNicotiana sylvestrise7
- Gene
- Complex Ie0
- Outcome
- lower stomatal and hydraulic conductancese0
- Qualifier
- oxidative and metabolic disturbancese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“oxidative and metabolic disturbances resulting from remodelled respira- tion in the absence of Complex I activity could be involved in bringing about the lower stomatal and hydraulic conductances”
e7“Nicotiana sylvestris wild type (WT) plants”