title: Is Change in Ovary Carbon Status a Cause or a Consequence of Maize Ovary Abortion in Water Deficit during Flowering?
abstract: Flower or grain abortion causes large yield losses under water deficit. In maize (Zea mays), it is often attributed to a carbon limitation via the disruption of sucrose cleavage by cell wall invertases in developing ovaries. We have tested this hypothesis versus another linked to the expansive growth of ovaries and silks. We have measured, in silks and ovaries of well-watered or moderately droughted plants, the transcript abundances of genes involved in either tissue expansion or sugar metabolism, together with the concentrations and amounts of sugars, and with the activities of major enzymes of carbon metabolism. Photosynthesis and indicators of sugar export, measured during water deprivation, suggested sugar export maintained by the leaf. The first molecular changes occurred in silks rather than in ovaries and involved genes affecting expansive growth rather than sugar metabolism. Changes in the concentrations and amounts of sugars and in the activities of enzymes of sugar metabolism occurred in apical ovaries that eventually aborted, but probably after the switch to abortion of these ovaries. Hence, we propose that, under moderate water deficits corresponding to most European drought scenarios, changes in carbon metabolism during flowering time are a consequence rather than a cause of the beginning of ovary abortion. A carbon-driven ovary abortion may occur later in the cycle in the case of carbon shortage or under very severe water deficits. These findings support the view that, until the end of silking, expansive growth of reproductive organs is the primary event leading to abortion, rather than a disruption of carbon metabolism.
authors.affiliation: INRA, UMR 759 LEPSE, 34060 Montpellier, France (V.O., C.F.C., F.T., O.T.);INRA, UMR Biologie du Fruit et Pathologie, 33883 Villenave d'Ornon, France (D.P., Y.G.);INRA, Plateforme Métabolome Bordeaux, 33883 Villenave d'Ornon, France (D.P.); andBiogemma, Centre de Rercherche de Chappes, 63720 Chappes, France (J.-P.P.).
authors.forename: Vincent
authors.identifier: 0000-0003-2994-0111
authors.initials: V
authors.lastname: Oury
authors.affiliation: INRA, UMR 759 LEPSE, 34060 Montpellier, France (V.O., C.F.C., F.T., O.T.);INRA, UMR Biologie du Fruit et Pathologie, 33883 Villenave d'Ornon, France (D.P., Y.G.);INRA, Plateforme Métabolome Bordeaux, 33883 Villenave d'Ornon, France (D.P.); andBiogemma, Centre de Rercherche de Chappes, 63720 Chappes, France (J.-P.P.).
authors.forename: Cecilio F
authors.identifier: 0000-0003-4762-3515
authors.initials: CF
authors.lastname: Caldeira
authors.affiliation: INRA, UMR 759 LEPSE, 34060 Montpellier, France (V.O., C.F.C., F.T., O.T.);INRA, UMR Biologie du Fruit et Pathologie, 33883 Villenave d'Ornon, France (D.P., Y.G.);INRA, Plateforme Métabolome Bordeaux, 33883 Villenave d'Ornon, France (D.P.); andBiogemma, Centre de Rercherche de Chappes, 63720 Chappes, France (J.-P.P.).
authors.forename: Duyên
authors.initials: D
authors.lastname: Prodhomme
authors.affiliation: INRA, UMR 759 LEPSE, 34060 Montpellier, France (V.O., C.F.C., F.T., O.T.);INRA, UMR Biologie du Fruit et Pathologie, 33883 Villenave d'Ornon, France (D.P., Y.G.);INRA, Plateforme Métabolome Bordeaux, 33883 Villenave d'Ornon, France (D.P.); andBiogemma, Centre de Rercherche de Chappes, 63720 Chappes, France (J.-P.P.).
authors.forename: Jean-Philippe
authors.identifier: 0000-0002-4220-1404
authors.initials: JP
authors.lastname: Pichon
authors.affiliation: INRA, UMR 759 LEPSE, 34060 Montpellier, France (V.O., C.F.C., F.T., O.T.);INRA, UMR Biologie du Fruit et Pathologie, 33883 Villenave d'Ornon, France (D.P., Y.G.);INRA, Plateforme Métabolome Bordeaux, 33883 Villenave d'Ornon, France (D.P.); andBiogemma, Centre de Rercherche de Chappes, 63720 Chappes, France (J.-P.P.).
authors.forename: Yves
authors.initials: Y
authors.lastname: Gibon
authors.affiliation: INRA, UMR 759 LEPSE, 34060 Montpellier, France (V.O., C.F.C., F.T., O.T.);INRA, UMR Biologie du Fruit et Pathologie, 33883 Villenave d'Ornon, France (D.P., Y.G.);INRA, Plateforme Métabolome Bordeaux, 33883 Villenave d'Ornon, France (D.P.); andBiogemma, Centre de Rercherche de Chappes, 63720 Chappes, France (J.-P.P.).
authors.forename: François
authors.initials: F
authors.lastname: Tardieu
authors.affiliation: INRA, UMR 759 LEPSE, 34060 Montpellier, France (V.O., C.F.C., F.T., O.T.);INRA, UMR Biologie du Fruit et Pathologie, 33883 Villenave d'Ornon, France (D.P., Y.G.);INRA, Plateforme Métabolome Bordeaux, 33883 Villenave d'Ornon, France (D.P.); andBiogemma, Centre de Rercherche de Chappes, 63720 Chappes, France (J.-P.P.) olivier.turc@supagro.inra.fr.
authors.forename: Olivier
authors.identifier: 0000-0003-0659-1406
authors.initials: O
authors.lastname: Turc
mesh_terms: D050260:Carbohydrate Metabolism; D002244:Carbon / Q000378:metabolism*; D055864:Droughts; D035264:Flowers / Q000235:genetics / Q000502:physiology; D018515:Plant Leaves / Q000235:genetics / Q000502:physiology; D014867:Water / Q000502:physiology*; D003313:Zea mays / Q000235:genetics / Q000502:physiology*
chemical_list: D014867:Water; D002244:Carbon