title: Sulla carnosa modulates root invertase activity in response to the inhibition of long-distance sucrose transport under magnesium deficiency.
abstract: Being the principal product of photosynthesis, sucrose is involved in many metabolic processes in plants. As magnesium (Mg) is phloem mobile, an inverse relationship between Mg shortage and sugar accumulation in leaves is often observed. Mg deficiency effects on carbohydrate contents and invertase activities were determined in Sulla carnosa Desf. Plants were grown hydroponically at different Mg concentrations (0.00, 0.01, 0.05 and 1.50 mM Mg) for one month. Mineral analysis showed that Mg contents were drastically diminished in shoots and roots mainly at 0.01 and 0.00 mM Mg. This decline was adversely associated with a significant increase of sucrose, fructose and mainly glucose in shoots of plants exposed to severe deficiency. By contrast, sugar contents were severely reduced in roots of these plants indicating an alteration of carbohydrate partitioning between shoots and roots of Mg-deficient plants. Cell wall invertase activity was highly enhanced in roots of Mg-deficient plants, while the vacuolar invertase activity was reduced at 0.00 mM Mg. This decrease of vacuolar invertase activity may indicate the sensibility of roots to Mg starvation resulting from sucrose transport inhibition.14CO2labeling experiments were in accordance with these findings showing an inhibition of sucrose transport from source leaves to sink tissues (roots) under Mg depletion. The obtained results confirm previous findings about Mg involvement in photosynthate loading into phloem and add new insights into mechanisms evolved by S. carnosa to cope with Mg shortage in particular the increase of the activity of cell wall invertase.
authors.affiliation: Laboratory of Extremophile Plants, Biotechnology Centre of Borj Cedria, Hammam-Lif, Tunisia. nejiafarhat@gmail.com.
authors.forename: N
authors.initials: N
authors.lastname: Farhat
authors.affiliation: Laboratory of Extremophile Plants, Biotechnology Centre of Borj Cedria, Hammam-Lif, Tunisia.
authors.forename: A
authors.initials: A
authors.lastname: Smaoui
authors.affiliation: UMR7267 - EBI - Equipe SEVE, CNRS/Université de Poitiers, Poitiers, France.
authors.forename: L
authors.initials: L
authors.lastname: Maurousset
authors.affiliation: UMR7267 - EBI - Equipe SEVE, CNRS/Université de Poitiers, Poitiers, France.
authors.forename: B
authors.initials: B
authors.lastname: Porcheron
authors.affiliation: UMR7267 - EBI - Equipe SEVE, CNRS/Université de Poitiers, Poitiers, France.
authors.forename: R
authors.initials: R
authors.lastname: Lemoine
authors.affiliation: Laboratory of Extremophile Plants, Biotechnology Centre of Borj Cedria, Hammam-Lif, Tunisia.
authors.forename: C
authors.initials: C
authors.lastname: Abdelly
authors.affiliation: Laboratory of Extremophile Plants, Biotechnology Centre of Borj Cedria, Hammam-Lif, Tunisia.|University of Hafr Al Batin, College of Science and Arts in Nairiyah, Nairiyah, Saudi Arabia.
authors.forename: M
authors.identifier: http://orcid.org/0000-0001-6817-585X
authors.initials: M
authors.lastname: Rabhi
mesh_terms: D001692:Biological Transport; D002473:Cell Wall / Q000201:enzymology; D007887:Fabaceae / Q000201:enzymology*; D008274:Magnesium / Q000378:metabolism*; D052585:Phloem / Q000201:enzymology; D018515:Plant Leaves / Q000201:enzymology; D010940:Plant Proteins / Q000378:metabolism; D018517:Plant Roots / Q000201:enzymology; D013395:Sucrose / Q000378:metabolism*; D043324:beta-Fructofuranosidase / Q000378:metabolism*
chemical_list: D010940:Plant Proteins; D013395:Sucrose; D043324:beta-Fructofuranosidase; D008274:Magnesium
keywords: Carbohydrate partitioning; cell wall invertase; magnesium depletion