Cecilia Brunetti1, Antonella Gori2, Giovanni Marino1, Paolo Latini3, Anatoly P Sobolev4, Andrea Nardini5, Matthew Haworth1, Alessio Giovannelli1, Donatella Capitani4, Francesco Loreto6, Gail Taylor7,8, Giuseppe Scarascia Mugnozza3, Antoine Harfouche3, Mauro Centritto1. 1. Trees and Timber Institute, National Research Council of Italy, Sesto Fiorentino (FI), Italy. 2. University of Florence, Department of Agri-Food Production and Environmental Sciences, Florence, Italy. 3. Dipartimento per la Innovazione nei sistemi Biologici, Agroalimentari e Forestali (DIBAF), Università degli Studi della Tuscia, Viterbo, Italy. 4. Istituto di Metodologie Chimiche, Consiglio Nazionale delle Ricerche, Monterotondo (Roma), Italy. 5. Dipartimento di Scienze della Vita, Università di Trieste, Trieste, Italy. 6. Dipartimento di Scienze Bio-Agroalimentari, Consiglio Nazionale delle Ricerche, Roma, Italy. 7. Centre for Biological Sciences, Faculty of Natural and Environmental Sciences, University of Southampton, Highfield Campus, Southampton, UK. 8. Department of Plant Sciences, University of California-Davis, CA, USA.
Abstract
BACKGROUND AND AIMS: Hydraulic and chemical signals operate in tandem to regulate systemic plant responses to drought. Transport of abscisic acid (ABA) through the xylem and phloem from the root to shoot has been suggested to serve as the main signal of water deficit. There is evidence that ABA and its ABA-glycosyl-ester (ABA-GE) are also formed in leaves and stems through the chloroplastic 2-C-methylerythritol-5-phosphate (MEP) pathway. This study aimed to evaluate how hormonal and hydraulic signals contribute to optimize stomatal (gs), mesophyll (gm) and leaf hydraulic (Kleaf) conductance under well-watered and water-stressed conditions in Populus nigra (black poplar) plants. In addition, we assessed possible relationships between ABA and soluble carbohydrates within the leaf and stem. METHODS: Plants were subjected to three water treatments: well-watered (WW), moderate stress (WS1) and severe stress (WS2). This experimental set-up enabled a time-course analysis of the response to water deficit at the physiological [leaf gas exchange, plant water relations, (Kleaf)], biochemical (ABA and its metabolite/catabolite quantification in xylem sap, leaves, wood, bark and roots) and molecular (gene expression of ABA biosynthesis) levels. KEY RESULTS: Our results showed strong coordination between gs, gm and Kleaf under water stress, which reduced transpiration and increased intrinsic water use efficiency (WUEint). Analysis of gene expression of 9-cis-epoxycarotenoid dioxygenase (NCED) and ABA content in different tissues showed a general up-regulation of the biosynthesis of this hormone and its finely-tuned catabolism in response to water stress. Significant linear relationships were found between soluble carbohydrates and ABA contents in both leaves and stems, suggesting a putative function for this hormone in carbohydrate mobilization under severe water stress. CONCLUSIONS: This study demonstrates the tight regulation of the photosynthetic machinery by levels of ABA in different plants organs on a daily basis in both well-watered and water stress conditions to optimize WUEint and coordinate whole plant acclimation responses to drought.
BACKGROUND AND AIMS: Hydraulic and chemical signals operate in tandem to regulate systemic plant responses to drought. Transport of abscisic acid (ABA) through the xylem and phloem from the root to shoot has been suggested to serve as the main signal of water deficit. There is evidence that ABA and its ABA-glycosyl-ester (ABA-GE) are also formed in leaves and stems through the chloroplastic 2-C-methylerythritol-5-phosphate (MEP) pathway. This study aimed to evaluate how hormonal and hydraulic signals contribute to optimize stomatal (gs), mesophyll (gm) and leaf hydraulic (Kleaf) conductance under well-watered and water-stressed conditions in Populus nigra (black poplar) plants. In addition, we assessed possible relationships between ABA and soluble carbohydrates within the leaf and stem. METHODS: Plants were subjected to three water treatments: well-watered (WW), moderate stress (WS1) and severe stress (WS2). This experimental set-up enabled a time-course analysis of the response to water deficit at the physiological [leaf gas exchange, plant water relations, (Kleaf)], biochemical (ABA and its metabolite/catabolite quantification in xylem sap, leaves, wood, bark and roots) and molecular (gene expression of ABA biosynthesis) levels. KEY RESULTS: Our results showed strong coordination between gs, gm and Kleaf under water stress, which reduced transpiration and increased intrinsic water use efficiency (WUEint). Analysis of gene expression of 9-cis-epoxycarotenoid dioxygenase (NCED) and ABA content in different tissues showed a general up-regulation of the biosynthesis of this hormone and its finely-tuned catabolism in response to water stress. Significant linear relationships were found between soluble carbohydrates and ABA contents in both leaves and stems, suggesting a putative function for this hormone in carbohydrate mobilization under severe water stress. CONCLUSIONS: This study demonstrates the tight regulation of the photosynthetic machinery by levels of ABA in different plants organs on a daily basis in both well-watered and water stress conditions to optimize WUEint and coordinate whole plant acclimation responses to drought.
Authors: Xiaodong Xie; Yibing Wang; Lisa Williamson; Geoff H Holroyd; Cecilia Tagliavia; Erik Murchie; Julian Theobald; Marc R Knight; William J Davies; H M Ottoline Leyser; Alistair M Hetherington Journal: Curr Biol Date: 2006-05-09 Impact factor: 10.834
Authors: Georg Zeller; Stefan R Henz; Christian K Widmer; Timo Sachsenberg; Gunnar Rätsch; Detlef Weigel; Sascha Laubinger Journal: Plant J Date: 2009-02-13 Impact factor: 6.417
Authors: Giuseppe Sorrentino; Matthew Haworth; Said Wahbi; Tariq Mahmood; Shi Zuomin; Mauro Centritto Journal: PLoS One Date: 2016-02-10 Impact factor: 3.240
Authors: G Taylor; I S Donnison; D Murphy-Bokern; M Morgante; M-B Bogeat-Triboulot; R Bhalerao; M Hertzberg; A Polle; A Harfouche; F Alasia; V Petoussi; D Trebbi; K Schwarz; J J B Keurentjes; M Centritto; B Genty; J Flexas; E Grill; S Salvi; W J Davies Journal: Ann Bot Date: 2019-10-29 Impact factor: 4.357