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Biosynthesis, transport and mechanism of action of nitric oxide durin crassulacean acid metabolism (CAM) induction in Guzmania monostachia

Grant number: 13/15108-1
Support Opportunities:Scholarships in Brazil - Doctorate
Effective date (Start): October 01, 2013
Effective date (End): July 31, 2016
Field of knowledge:Biological Sciences - Botany - Pant Physiology
Principal Investigator:Helenice Mercier
Grantee:Paulo Tamaso Mioto
Host Institution: Instituto de Biociências (IB). Universidade de São Paulo (USP). São Paulo , SP, Brazil
Associated research grant:11/50637-0 - Competence for Crassulacean Acid Metabolism (CAM) expression in epiphytic bromeliad: signaling, modulation of expression, transcriptional profile and interaction with the nitrogen metabolism, AP.TEM


Crassulacean Acid Metabolism (CAM) is an important adaptation to low-water environments. Some species are capable of altering their photosynthetic metabolism in response to abiotic stresses, such as drought. CAM up-regulation in tank bromeliads occurs differently along the leaf length, since the apical portion express CAM more strongly than the basal portion of the leaf. Recently, in our laboratory, it was found that nitric oxide (NO) appears to be involved in CAM signaling in Guzmania monostachia, a tank bromeliad. NO was already linked to several processes in plants, but there are wide gaps in the knowledge of how this molecule is synthesized and its mode of action. There are two relatively well established pathways of NO synthesis: the enzyme nitrate reductase (NR) and a pathway called NOS (nitric oxide synthase), in which no enzyme has been characterized. Once synthesized, NO may be transported through S-nitroso glutathione (GSNO) or interact locally with proteins through S-nytrosilation. The aim of this work is to evaluate the production, transport and mechanism of action of NO during CAM induction in G. monostachia a C3-CAM epiphytic tank bromeliad. Detached leaves will be kept in a 30% polyethylene glycol 6000 solution (PEG) in order to simulate drought. The control leaves will be kept in distilled water. CAM induction will be assessed through quantification of phosphoenol carboxylase (PEPC) activity and expression, and nocturnal accumulation of organic acids. During the eight days of experiment, NO emission will be measured and, later, the leaves will be subjected to scavengers or donors of this compound. This approaches will determine if NO levels in the plant change in response to water deficit and if NO is indispensable for CAM up-regulation. NR and NOS pathways will be suppressed separately to determine which one of them contributes more to NO production. GSNO will be quantified to investigate if there is transport of NO along the leaf. Finally, the proteins that are S-nitrosylated in response to water deficit will be characterized, and S-nyrtisylation inhibitors will be given to the plant in order to determine if this process is indispensable for CAM induction. All analyses will be performed in at least two portions of the leaf: basal and apical. The basal portion would be a control, since it does not up-regulate CAM in response to drought.

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Scientific publications
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
MIOTO, PAULO TAMASO; RODRIGUEZ-RUIZ, MARTA; MOT, AUGUSTIN CATALIN; ZUCCARELLI, RAFAEL; CORPAS, FRANCISCO J.; FRESCHI, LUCIANO; MERCIER, HELENICE. Alternative fluorimetric-based method to detect and compare total S-nitrosothiols in plants. NITRIC OXIDE-BIOLOGY AND CHEMISTRY, v. 68, p. 7-13, . (13/18056-2, 13/15108-1, 11/50637-0)
PIKART, FILIPE C.; MARABESI, MAURO A.; MIOTO, PAULO T.; GONCALVES, ANA Z.; MATIZ, ALEJANDRA; ALVES, FREDERICO R. R.; MERCIER, HELENICE; AIDAR, MARCOS P. M.. The contribution of weak CAM to the photosynthetic metabolic activities of a bromeliad species under water deficit. Plant Physiology and Biochemistry, v. 123, p. 297-303, . (11/50637-0, 16/04924-0, 16/09699-5, 13/15108-1)
RODRIGUES, MARIA AURINEIDE; HAMACHI, LEONARDO; MIOTO, PAULO TAMASO; PURGATTO, EDUARDO; MERCIER, HELENICE. Implications of leaf ontogeny on drought-induced gradients of CAM expression and ABA levels in rosettes of the epiphytic tank bromeliad Guzmania monostachia. Plant Physiology and Biochemistry, v. 108, p. 400-411, . (11/04963-2, 11/50637-0, 13/15108-1)
Academic Publications
(References retrieved automatically from State of São Paulo Research Institutions)
MIOTO, Paulo Tamaso. Crassulacean Acid Metabolism (CAM) regulation by nitric oxide in Guzmania monostachia. 2016. Doctoral Thesis - Universidade de São Paulo (USP). Instituto de Biociências (IBIOC/SB) São Paulo.

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