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Made available in DSpace on 2019-10-04T12:34:49Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-02-27 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Blossom end rot is one of the main physiological disorders of the tomato crop. Usually, the blossom end rot (BER) occurrence is associated with fruit calcium (Ca2+) deficiency; however, increasing evidence of Ca2+ disorders and hormonal regulation has emerged. Therefore, the present work was undertaken to investigate the role of gibberellin (GA) signaling on the control of tomato plant responses to Ca2+ deficiency. In this study, we used the tomato mutant procera (pro), which has a constitutive response to GA, and its isogenic line cv. Micro-Tom (MT) grown in a hydroponic system with or without Ca2+. Subsequently, the analysis of the growth of the shoot and the root system was performed, and the contents of photosynthetic pigments and oxidative stress were also analyzed. Furthermore, the fruit production, BER incidence, accumulation and metabolism of Ca2+ were also analyzed. The deficiency of Ca2+ reduced both shoot and root growth in both genotypes. Likewise, photosynthetic pigment degradation and oxidative stress were induced by Ca2+ deficiency. However, only pro plants exhibited the inhibition of fruit dry mass, as well as a higher incidence of BER, when exposed to Ca2+ deficiency compared to MT plants. In accordance with the greater pro susceptibility to Ca2+ deficiency, the efficiency of the transport, use and accumulation of Ca2+ in fruits was lower in pro when compared to the MT. Thus, we conclude that the higher sensitivity to GA in pro plants impairs Ca2+ metabolism and favors the occurrence of BER in tomato fruits, opening new approaches for the GA signaling on BER response. Sao Paulo State Univ, Dept Biol Appl Agr, Via Acesso Prof Paulo Donato Castellane S-N, BR-14884900 Jaboticabal, Brazil Sao Paulo State Univ, Dept Soil & Fertilizer, Via Acesso Prof Paulo Donato Castellane S-N, BR-14884900 Jaboticabal, Brazil Sao Paulo State Univ, Dept Biol Appl Agr, Via Acesso Prof Paulo Donato Castellane S-N, BR-14884900 Jaboticabal, Brazil Sao Paulo State Univ, Dept Soil & Fertilizer, Via Acesso Prof Paulo Donato Castellane S-N, BR-14884900 Jaboticabal, Brazil

[EN] Plants are sessile organisms that must perceive and respond to various environmental constraints throughout their life cycle. Among these constraints, drought stress has become the main limiting factor to crop production around the world. Water deprivation is perceived primarily by the roots, which efficiently signal the shoot to trigger drought responses in order to maximize a plant's ability to survive. In this study, the tomato (Solanum lycopersicum L.) mutant procera (pro), with a constitutive response to gibberellin (GA), and its near isogenic line cv. Micro-Tom (MT), were used in reciprocal grafting under well-watered and water stress conditions to evaluate the role of GA signaling in root-to-shoot communication during drought stress. Growth, oxidative stress, gene expression, water relations and hormonal content were measured in order to provide insights into GA-mediated adjustments to water stress. All graft combinations with pro (i.e. pro/pro, MT/pro and pro/MT) prevented the reduction of growth under stress conditions without a reduction in oxidative stress. The increase of oxidative stress was followed by upregulation of SlDREB2, a drought-tolerance related gene, in all drought-stressed plants. Scions harboring the pro mutation tended to increase the abscisic acid (ABA) content, independent of the rootstock. Moreover, the GA sensitivity of the rootstock modulated stomatal conductance and water use efficiency under drought stress, indicating GA and ABA crosstalk in the adjustment of growth and water economy., The Sao Paulo Research Foundation (FAPESP) for doctoral fellowship to the first author under grant 2014/19165-2.

Made available in DSpace on 2021-06-25T11:12:03Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-03-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) The participation of plant cryptochromes in water deficit response mechanisms has been highlighted in several reports. However, the role of tomato (Solanum lycopersicum L.) cryptochrome 1a (cry1a) in the blue light fluence-dependent modulation of the water deficit response remains largely elusive. The tomato cry1a mutant and its wild-type counterpart were grown in water (no stress) or PEG6000 (osmotic stress) treatments under white light (60 μmol m−2 s-1) or from low to high blue light fluence (1, 5, 10, 15 and 25 μmol m−2 s-1). We first demonstrate that under nonstress conditions cry1a regulates seedling growth by mechanisms that involve pigmentation, lipid peroxidation and osmoprotectant accumulation in a blue light-dependent manner. In addition, we further highlighted under osmotic stress conditions that cry1a increased tomato growth by reduced malondialdehyde (MDA) and proline accumulation. Although blue light is an environmental signal that influences osmotic stress responses mediated by tomato cry1a, specific blue light fluence rates are required during these responses. Here, we show that CRY1a manipulation may be a potential biotechnological target to develop a drought-tolerant tomato variety. Nevertheless, the complete understanding of this phenomenon requires further investigation. Department of Biology Applied to Agriculture São Paulo State University (UNESP) University of Marília (UNIMAR) Federal University of Mato Grosso do Sul (UFMS) Department of Biology Applied to Agriculture São Paulo State University (UNESP) FAPESP: 2017/26130-9