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Accueil du site → Doctorat → Allemagne → 2013 → Altering ABA levels in leaf and seed tissue of barley to study the role of ABA on plant performance under post-anthesis drought stress using the transgenic approach

Martin-Luther-Universität Halle-Wittenberg (2013)

Altering ABA levels in leaf and seed tissue of barley to study the role of ABA on plant performance under post-anthesis drought stress using the transgenic approach

Harshavardhan, Vokkaliga T

Titre : Altering ABA levels in leaf and seed tissue of barley to study the role of ABA on plant performance under post-anthesis drought stress using the transgenic approach

Auteur : Harshavardhan, Vokkaliga T

Université de soutenance : Martin-Luther-Universität Halle-Wittenberg

Grade : Doctoral Thesis 2013

Résumé
Drought is one of the major abiotic stresses that largely impair plant growth and development. However, plants perceive and respond to abiotic stress with adaptive processes mainly controlled by sesquiterpene phytohormone abscisic acid (ABA). In current study, ABA levels in barley plants was altered, by transforming plants with AtNCED6 driven by a stress-inducible SalT promoter (SN) or seed specific 1AX1 promoter (XN), to study the role of ABA during post-anthesis drought. Physiological, biochemical and molecular analysis of untransformed and transgenic plants under control and post-anthesis drought revealed the probable mechanism by which ABA affects plant performance and yield under stress. WT, SN and XN plants differed in their ABA levels under control and stress condition. Early peaking of ABA (2 Days after stress ; DAS) in leaves of SN plants under stress probably helped in triggering genes that play a role in cellular protection. This was evident by the maintenance of high percent leaf RWC content by SN plants under stress (4 DAS) compared to WT plants that had high ABA level relatively late. This also helped SN plants to maintain higher photosynthetic rate than WT plants, under stress. In addition, under stress, ABA levels reached basal levels (8/10 Days after flowering ; DAF- 16/20 DAF) after an initial increase of ABA (6 DAF) in seeds of SN while in WT and XN seeds the ABA levels did not reach basal levels. The impact of this was seen in terms of low rate of starch accumulation in WT and XN under stress. It can be concluded that high levels of ABA during 8/10 DAF – 16/20 DAF, a phase most sensitive to alterations in basal ABA levels, affects thousand grain weights especially when grain filling period is limiting.

Mots Clés : Gerste ; Trockenheit ; transgen ; ABA ; Homöostase ; Barley ; drought ; transgenic ; ABA ; homeostasis

Présentation et version intégrale de la thèse

Page publiée le 14 janvier 2014, mise à jour le 19 novembre 2016