| Full text | |
| Author(s): |
Goncalves, Ana Zangirolame
[1]
;
Rayner Oliveira, Paulo Marcelo
[1]
;
Coutinho Neto, Antonio Azeredo
[1]
;
Mercier, Helenice
[1]
Total Authors: 4
|
| Affiliation: | [1] Univ Sao Paulo, Inst Biociencias, Dept Bot, Rua Matao 277, BR-05508090 Sao Paulo - Brazil
Total Affiliations: 1
|
| Document type: | Journal article |
| Source: | ENVIRONMENTAL AND EXPERIMENTAL BOTANY; v. 178, OCT 2020. |
| Web of Science Citations: | 1 |
| Abstract | |
Epiphytic bromeliads are subjected to intermittent nutrient availability while at the same time having a small root system that absorb a small amount of nutrients. These bromeliads possess adaptations, such as a tank formation and a higher trichome density, that contribute to their acquisition of water and nutrients. However, little is known about the nitrogen metabolism in epiphytic tank bromeliads or how ammonium reaches the leaf apex before its assimilation, and nothing has been described about the functioning of the low- and high-affinity nitrogen transporters in epiphytic plants whose leaves play a key role in nutrient uptake. In this context, we conducted a controlled experiment with Guzmania monostachia to investigate its nutritional preference when nitrate, ammonium and urea are offered at the same time, its nitrogen assimilation along the leaf blade, and whether the high-affinity nitrogen transporters (NRT2.5, AMT(1.2), DUR3) present the highest gene expressions under low nitrogen availability. Our results revealed that the leaf base was responsible for nitrogen absorption and ammonium production through urease and NR activities and showed an upregulation of the high-affinity transporters of nitrate and ammonium NRT2.5, AMT(1.2)), together with the urea transporter genes (DUR3, aquaporin TIP2.1). On the other hand, the leaf apex presented remarkable characteristics relating to GS activity and showed the highest gene expression of low-affinity nitrate (NRT1.2) and ammonium (AMT(3.1), aquaporin PIP1.2) transporters. These results suggest that nitrogen absorption and assimilation occurred in a single leaf in G. monostachia as its leaves played the role of a whole plant regarding nitrogen metabolism. The leaf base was essential in nitrogen absorption, nitrate reduction, and urea hydrolysis. In this leaf portion, the upregulation of the high-affinity transporters could ensure efficient nitrogen uptake even in low concentrations. In an epiphytic environment, with extremely limited nutrient availability, the bromeliad leaves seem to be the main organ that guarantees plant survival. (AU) | |
| FAPESP's process: | 16/09699-5 - Nitrogen metabolism and its interaction with the Crassulacean acid metabolism (CAM) in Guzmania monostachia (Bromeliaceae): a physiological and molecular approach |
| Grantee: | Ana Zangirólame Gonçalves |
| Support Opportunities: | Scholarships in Brazil - Post-Doctoral |
| FAPESP's process: | 18/12667-3 - Exploring the physiological and molecular aspects of Guzmania monostachia (Bromeliaceae): studying the functional pathways of photosynthesis and nutrient responses. |
| Grantee: | Helenice Mercier |
| Support Opportunities: | Regular Research Grants |
| FAPESP's process: | 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 |
| Grantee: | Helenice Mercier |
| Support Opportunities: | Research Projects - Thematic Grants |