title: Respiratory complex I deficiency induces drought tolerance by impacting leaf stomatal and hydraulic conductances.
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 levels 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 conductance. 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 stomatal 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 respiration in the absence of Complex I activity could be involved in bringing about the lower stomatal and hydraulic conductances.
authors: Laboratoire de Physiologie et Biologie des Organismes, Université des Sciences et de la Technologie Houari Boumediene, BP 39, El Alia, Bab Ezzouar, Algiers, Algeria.
authors: Reda
authors: R
authors: Djebbar
authors: Touhami
authors: T
authors: Rzigui
authors: Pierre
authors: P
authors: Pétriacq
authors: Caroline
authors: C
authors: Mauve
authors: Pierrick
authors: P
authors: Priault
authors: Chantal
authors: C
authors: Fresneau
authors: Marianne
authors: M
authors: De Paepe
authors: Igor
authors: I
authors: Florez-Sarasa
authors: Ghouziel
authors: G
authors: Benhassaine-Kesri
authors: Peter
authors: P
authors: Streb
authors: Bertrand
authors: B
authors: Gakière
authors: Gabriel
authors: G
authors: Cornic
authors: Rosine
authors: R
authors: De Paepe
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D055864:Droughts; D042967:Electron Transport Complex I / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant / Q000235:genetics / Q000502:physiology; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D054046:Plant Stomata / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*
chemical_list: D000040:Abscisic Acid; D000255:Adenosine Triphosphate; D042967:Electron Transport Complex I