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Gama F, Saavedra T, Dandlen S, de Varennes A, Correia PJ, Pestana M, Nolasco G. Silencing of the FRO1 gene and its effects on iron partition in Nicotiana benthamiana. Plant Physiol Biochem 2017; 114:111-118. [PMID: 28285085 DOI: 10.1016/j.plaphy.2017.03.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 03/02/2017] [Accepted: 03/03/2017] [Indexed: 05/01/2023]
Abstract
To evaluate the dynamic role of the ferric-chelate reductase enzyme (FCR) and to identify possible pathways of regulation of its activity in different plant organs an investigation was conducted by virus-induced gene silencing (VIGS) using tobacco rattle virus (TRV) to silence the ferric reductase oxidase gene (FRO1) that encodes the FCR enzyme. Half of Nicotiana benthamiana plants received the VIGS vector and the rest remained as control. Four treatments were imposed: two levels of Fe in the nutrient solution (0 or 2.5 μM of Fe), each one with silenced or non-silenced (VIGS-0; VIGS-2.5) plants. Plants grown without iron (0; VIGS-0) developed typical symptoms of iron deficiency in the youngest leaves. To prove that FRO1 silencing had occurred, resupply of Fe (R) was done by adding 2.5 μM of Fe to the nutrient solution in a subset of chlorotic plants (0-R; VIGS-R). Twelve days after resupply, 0-R plants had recovered from Fe deficiency while plants containing the VIGS vector (VIGS-R) remained chlorotic and both FRO1 gene expression and FCR activity were considerably reduced, consequently preventing Fe uptake. With the VIGS technique we were able to silence the FRO1 gene in N. benthamiana and point out its importance in chlorophyll synthesis and Fe partition.
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Affiliation(s)
- Florinda Gama
- MeditBio - Center for Mediterranean Bioresources and Food, University of Algarve, FCT, Ed8, Campus of Gambelas, 8005-139 Faro, Portugal.
| | - Teresa Saavedra
- MeditBio - Center for Mediterranean Bioresources and Food, University of Algarve, FCT, Ed8, Campus of Gambelas, 8005-139 Faro, Portugal
| | - Susana Dandlen
- MeditBio - Center for Mediterranean Bioresources and Food, University of Algarve, FCT, Ed8, Campus of Gambelas, 8005-139 Faro, Portugal
| | - Amarilis de Varennes
- LEAF - Linking Landscape, Environment, Agriculture and Food, Instituto Superior de Agronomia, University of Lisbon, Tapada da Ajuda, 1349-017 Lisbon, Portugal
| | - Pedro J Correia
- MeditBio - Center for Mediterranean Bioresources and Food, University of Algarve, FCT, Ed8, Campus of Gambelas, 8005-139 Faro, Portugal
| | - Maribela Pestana
- MeditBio - Center for Mediterranean Bioresources and Food, University of Algarve, FCT, Ed8, Campus of Gambelas, 8005-139 Faro, Portugal
| | - Gustavo Nolasco
- MeditBio - Center for Mediterranean Bioresources and Food, University of Algarve, FCT, Ed8, Campus of Gambelas, 8005-139 Faro, Portugal
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Correia PJ, Martins-Loução MA. Leaf nutrient variation in mature carob (Ceratonia siliqua) trees in response to irrigation and fertilization. Tree Physiol 1997; 17:813-819. [PMID: 14759891 DOI: 10.1093/treephys/17.12.813] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Seasonal variations in leaf nitrogen, phosphorus and potassium concentrations were studied in a mature carob (Ceratonia siliqua L. cv "Mulata") orchard subjected to a 4-year irrigation and fertilization experiment. Three irrigation regimes (0, 50 and 100%), based on the evaporation values obtained from a class A pan, were tested in combination with two nitrogen (N) supply regimes in which 21 kg ha(-1) year(-1) (low-N) and 63 kg ha(-1) year(-1) (high-N) were supplied as ammonium nitrate. Leaf nitrogen concentration increased throughout the experiment, independently of treatments. There were no significant differences in leaf N concentration between trees in the high-N and low-N treatments. Irrigation regimes had no effect on leaf mineral concentration but influenced the amount of leaves shed and slightly modified the pattern of leaf shedding that occurred during the summer drought period. Nutritional balances between N and P and N and K were both closely and significantly correlated. Potassium was translocated from leaves to fruits during spring, independently of treatments. Severe water stress periods occurring during spring or autumn induced shedding of leaves leading to nutrient mobilization. Nutrient retranslocation during these drought periods may represent an adaptive mechanism. Nitrogen retranslocation was higher for trees in the high-N treatments than for trees in the low-N treatments, whereas phosphorus retranslocation was independent of the irrigation and fertilization treatments.
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