| Autor: |
Matiz A; Department of Botany, Institute of Biosciences, University of São Paulo, São Paulo, SP, CEP 05508-090, Brazil. alematiz@usp.br., Cambuí CA; Department of Botany, Institute of Biosciences, University of São Paulo, São Paulo, SP, CEP 05508-090, Brazil., Richet N; Louvain Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud 4-L7.07.14, 1348, Louvain-la-Neuve, Belgium., Mioto PT; Department of Botany, Biological Sciences Center, Federal University of Santa Catarina, Campus Reitor João David Ferreira Lima, s/n, Florianópolis, SC, CEP 88040-900, Brazil., Gomes F; Department of Genetics and Evolutionary Biology, Institute of Biosciences, University of São Paulo, São Paulo, SP, CEP 05508-090, Brazil., Pikart FC; Department of Botany, Institute of Biosciences, University of São Paulo, São Paulo, SP, CEP 05508-090, Brazil., Chaumont F; Louvain Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud 4-L7.07.14, 1348, Louvain-la-Neuve, Belgium., Gaspar M; Department of Plant Physiology and Biochemistry, Institute of Botany, São Paulo, SP, CEP 04301-912, Brazil., Mercier H; Department of Botany, Institute of Biosciences, University of São Paulo, São Paulo, SP, CEP 05508-090, Brazil. |
| Abstrakt: |
Main Conclusion: Depending on the N source and plant ontogenetic state, the epiphytic tank-forming bromeliad Vriesea gigantea can modulate aquaporin expression to maximize the absorption of the most available nitrogen source. Epiphytic bromeliads frequently present a structure formed by the overlapping of leaf bases where water and nutrients can be accumulated and absorbed, called tank. However, this structure is not present during the juvenile ontogenetic phase, leading to differences in nutrient acquisition strategies. Recent studies have shown a high capacity of the bromeliad Vriesea gigantea, an epiphytic tank-forming bromeliad, to absorb urea by their leaves. Since plant aquaporins can facilitate the diffusion of urea through the membranes, we cloned three foliar aquaporin genes, VgPIP1;1, VgPIP1;2 and VgTIP2;1 from V. gigantea plants. Through functional studies, we observed that besides water, VgTIP2;1 was capable of transporting urea while VgPIP1;2 may facilitate ammonium/ammonia diffusion. Moreover, aiming at identifying urea and ammonium-induced changes in aquaporin expression in leaves of juvenile and adult-tank plants, we showed that VgPIP1;1 and VgPIP1;2 transcripts were up-regulated in response to either urea or ammonium only in juvenile plants, while VgTIP2;1 was up-regulated in response to urea only in adult-tank plants. Thereby, an ontogenetic shift from juvenile to adult-tank-forming-plant appears to occur with metabolic changes regarding nitrogen metabolism regulation. Investigating urea metabolism in wild species that naturally cope with organic N sources, such as V. gigantea, may provide the knowledge to modify nitrogen use efficiency of crop plants. |
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