Part 1: Ecophysiology of Bromeliaceae
Ecophysiological strategies in Bromeliaceae: how distinct traits favored their irradiance in a wide range of environments
Ana Zangirolame Gonçalves1
1Universidade de São Paulo (USP). zangirolame@usp.br
Bromeliaceae is a monophyletic family that occupies many resource-poor environments; however, bromeliads possess traits that allow their efficient water and nutrient use and uptake, including the presence of foliar trichomes, phytotelmata (tanks with water), the diversification of the carbon metabolism and contrasting growth forms. Besides distinct subfamilies, bromeliads are divided into five ecophysiological types according to their sources of nutrients (soil, tank) and their way to access them (trichomes, roots). In this context, new researches are showing distinct physiological, anatomical and molecular traits among Bromeliaceae subfamilies and ecophysiological types. For example, bromeliads have a trade-off between the use of nitrogen for soluble protein production and immediate growth or to store it in amino acids for transamination reactions during nutritional stress.
In another example, Guzmania monostachia performed a weak CAM but kept the integrity of the PSII, suggesting a metabolic strategy to maintain plant fitness even in water deficit conditions.
Additionally, the expression of genes associated with the nitrogen metabolism and the resistance to oxidative stress appears to be different in bromeliad leaf portions, suggesting high foliar adaptation to nutritional and water variations. These results highlight the ecophysiological plasticity of bromeliads to deal with a wide range of environments.
Key words: ecophysiological types, foliar adaptation, nitrogen use efficiency, resource-poor environment, water use efficiency.
Funded by: FAPESP (Proc n° 2016/09699-5)
Effects of drought and water supply on the performance of tank bromeliads
Céline Leroy1, Eva Gril2, Sabrina Coste3, Bastien Gérard4, Pascale Maillard4, Helenice Mercier5, Lynda Si Ouali4 & Clément Stahl4
1Institut de Recherche pour le Développement; 2AgroParisTech; 3Université de Guyane; 4Institut National de la Recherche Agronomique; 5Universidade de Sao Paulo. celine.leroy@ird.fr
The epiphytic habit represents a stressful environment for bromeliads. Drought stress has been studied mainly on atmospheric-epiphytes because of their inability to trap external water in a tank.
However, future climate scenarios forecast up to 50% decline in rainfall, which could also impact epiphytes. The objectives were to evaluate water relations and water stress between two tank-epiphytic species from C3 and CAM metabolisms. Plant performance was compared, based on a drought gradient and water supply experiments, using a set of functional traits related to plant growth, resource capture and resource-use strategies. We demonstrated that the performance of both species declines with increasing drought stress but with some contrasting physiological responses between species at intermediary stress. Additionally, we showed that these two species had contrasting functioning in leaf vs. roots for water and nutrient uptake. While the roots of the C3
tank-epiphyte played only a marginal role in the uptake of water, in the CAM species the roots did contribute to plant water and nutrient balance. The occurrence of CAM and C3 metabolisms in tank-epiphytes do have implications in the response to drought gradient and for water and nutrient acquisition.
Key words: drought, functional traits, photosynthetic metabolism, tank-bromeliads, water and nutrient uptake.
Exploring the physiological and molecular aspects of some functional pathways along the leaves of Guzmania monostachia (Bromeliaceae)
Helenice Mercier1
1Department of Botany, University of São Paulo. hmercier@usp.br
Bromeliaceae includes species spanning a wide diversity of habitats throughout Neotropical ecosystems. Nearly half of all bromeliads are epiphytes, and their representatives often display highly specialized adaptations to survive in extreme environments. Many adaptations exist in epiphytic bromeliads and they represent key strategies to efficiently intercept, absorb, and store water and nutrients. Among them, one of the most studied i CAM photosynthesis. However, the molecular basis behind the morpho-functional biology of those important plants remains to be discovered. We have chosen the epiphytic-tank bromeliad Guzmania monostachia, the only well-recognized CAM facultative species amongst Bromeliaceae, to perform a deep sequencing, transcriptome assembly, followed by differential expression analysis across several tissues along the proximal-distal leaf axis (base, middle, apical leaf portions) in response to varied conditions of water and/or nutrient availability. The transcriptional profiles obtained in our RNA-seq analysis highlight the existence of a clear morpho-functional heterogeneity along leaf blades of epiphytic-tank bromeliads with a specialization gradient typically varying from the base to the leaf apex, chlorophyll-rich regions being more related to metabolic-assimilatory processes and the leaf bases to nutrient responses.
Key words: CAM photosynthesis, epiphyte, nutrient responses, RNA-seq, water availability.
Funded by: FAPESP/CNPq
Part 2: Adaptations and conservation of Bromeliaceae in Brazilian hotspots
Evolution and conservation of bromeliads from hotspots: a case study from the cerrado-pantanal-chaco species
Gecele Matos Paggi1, Gislaine Moreira de Miranda2, Luciana Vicente da Silva3, Fernanda Maria de Russo Godoy4, Brenda Baía Brandão2 & Camila Martini Zanella5
1Universidade Federal de Mato Grosso do Sul, Ciências Biológicas, Campus do Pantanal, Corumbá, MS, Brazil; 2Universidade Federal de Mato Grosso do Sul, Programa de Pós-Graduação em
Biologia Vegetal, Instituto de Biociências, Campo Grande, MS, Brazil; 3Universidade Federal de Mato Grosso do Sul, Programa de Pós-Graduação em Ecologia e Conservação, Instituto de
Biociências, Campo Grande, MS, Brazil; 4Universidade Federal de Mato Grosso do Sul, Programa de Pós-Graduação em Biotecnologia e Biodiversidade, Faculdade de Ciências Farmacêuticas, Alimentos e Nutrição, Campo Grande, MS, Brazil; 5The John Bingham Laboratory, National Institute of Agricultural Botany, Cambridge, UK. gecele.paggi@ufms.br
Data generated by population genetics research can be used to define conservation units and priorities for the management of genetic resources, indicating populations of importance for the conservation of species. The present study described patterns of population structure, genetic diversity and gene flow of D. ferruginea, which occurs in Cerrado areas in Mato Grosso do Sul, Central Brazil. Six microsatellite markers were used for both nuclear (HO = 0.218 and HE = 0.787) and plastidial (HE = 0.917 to HE = 1.000 and 39 haplotypes) genomes. There were significant deviations from the Hardy-Weinberg Equilibrium, with an inbreeding coefficient of 0.760. A large genetic variation was observed within the populations for both nuclear (88.39%) and plastidial (91.87%) microsatellites, with moderate genetic structure (FST = 0.116). Moderate levels of genetic differentiation between populations were found considering FST comparisons. The number of migrants per generation ranged from 0.299 to 1.308, which maintains the cohesion of populations although with low gene flow. There is no record that D. ferruginea is included in Conservation Units or in any list of endangered species. Therefore, species conservation strategies are necessary to ensure that D. ferruginea will be protected as well as the Cerrado ecosystem.
Key words: conservation, gene flow, microsatellites, Pitcairnioideae, population genetics.
Funded by: CNPq, CAPES, FUNDECT
Drivers of bromeliad trait variation across a latitudinal gradient in the Brazilian Atlantic Forest hotspot
Beatriz Neves1, Camila Martini Zanella2, Igor Musauer Kessous3, Christine Dorothy Bacon4, Fabiano Salgueiro5, Fernanda Bered6, Alexandre Antonelli7 & Andrea Ferreira da Costa8
1Programa de Pós-Graduação em Ciências Biológicas (Botânica), Universidade Federal do Rio de Janeiro, Quinta da Boa Vista, São Cristóvão, CEP 20949-040, Rio de Janeiro, RJ, Brazil; 2National Institute of Agricultural Botany, Department of Genetics and Breeding, Huntingdon Road,
CB30LE, Cambridge, United Kingdom; 3Programa de Pós-Graduação em Ciências Biológicas (Botânica), Universidade Federal do Rio de Janeiro, Quinta da Boa Vista, São Cristóvão, CEP 20949-040, Rio de Janeiro, RJ, Brazil; 4University of Gothenburg, Department of Biological and Environmental Sciences, Carl Skottsbergs Gata 22B, SE 41319, Göteborg, Sweden; Gothenburg Global Biodiversity Centre, Carl Skottsbergs Gata 22B, SE 41319, Göteborg, Sweden;
5Universidade Federal do Estado do Rio de Janeiro, Departamento de Botânica, Av. Pasteur, 458, 22.290-240, Rio de Janeiro, RJ, Brazil;; 6Universidade Federal do Rio Grande do Sul,
Departamento de Genética, Rio Grande do Sul, Brazil; 7University of Gothenburg, Department of Biological and Environmental Sciences, Carl Skottsbergs Gata 22B, SE 41319, Göteborg, Sweden;
Gothenburg Global Biodiversity Centre, Carl Skottsbergs Gata 22B, SE 41319, Göteborg, Sweden;
Gothenburg Botanical Garden, Carl Skottsbergs Gata 22B, SE 41319, Göteborg, Sweden;
8Departamento de Botânica, Museu Nacional, Universidade Federal do Rio de Janeiro, Quinta da Boa Vista, São Cristóvão, 20949-040, Rio de Janeiro, Brazil. biazinhaa_neves@hotmail.com
The hyperdiverse Atlantic Forest stands out as a biodiversity hotspot in which bromeliads underwent a significant rapid diversification. We investigate size and shape variation of leaves and floral bracts of three closely related Vriesea taxa across a latitudinal gradient in the biome to test the contribution of genetics, climate, and topography as driving forces. Morphology was assessed using geometric morphometrics. Genetic structure was assessed using two cpDNA regions.
Environmental variables most important to explain variation were selected through PCA. We tested the influence of the predictors using linear mixed-effect models. We found that shifts in shape correlate with climate and chloroplast divergence, whereas size reflects local environment conditions. We also detected a phylogeographic break in species distribution between the northern and southern portions of the forest, from where species likely diverged around 4 Mya during Late Quaternary.
Key words: biogeography, climatic shifts, floral bract shape, geometric morphometrics, leaf shape.
Funded by: The study was supported by the Coordenação de Aperfeiçoamento Pessoal (Capes), the Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ) and the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) through fellowships and financial help for field and lab works.