A carregar...
Projeto de investigação
Sem título
Financiador
Autores
Publicações
Lipid profile adjustments may contribute to warming acclimation and to heat impact mitigation by elevated CO2 in Coffea spp
Publication . Scotti-Campos, Paula; Pais, Isabel B.; Ribeiro-Barros, Ana I.; Martins, Lima D.; Tomaz, Marcelo A.; Rodrigues, Weverton P.; Campostrini, Eliemar; Semedo, José N.; Fortunato, Ana S.; Martins, Madlles Q.; Partelli, Fábio; Lidon, Fernando C.; DaMatta, Fábio M.; Ramalho, José C.
An unexpected heat resilience, and the mitigation of heat impacts by elevated [CO2] were recently reported in Coffea
spp. Plants must maintain membrane fluidity and integrity to cope with temperature changes, which requires an
adequate lipid dynamics. This work provides the lipid profile (galactolipids, GL; phospholipids, PL; sulfolipids, SL) of
chloroplast membranes, and the expression of a set of genes related to lipid metabolism in Coffea arabica L. (cv. Icatu
and IPR108) and C. canephora cv. Conilon CL153, under elevated [CO2] (380 or 700 μL L−1), heat (25/20, 31/25,
37/30 and 42/34 °C, day/night) and their interaction. Major membrane lipids alterations, different among genotypes,
included: A) responsiveness of total fatty acids (TFAs) synthesis to [CO2] (except IPR108) and heat (except
CL153); stronger remodeling (unsaturation degree) in the 700-plants from 37/30 °C to 42/34 °C, coordinated at
transcriptional level with the down-regulation of fatty acid desaturase FAD3 gene (C. arabica) and up-regulation of
lipoxygenase genes LOX5A (CL153 and Icatu) and LOX5B (Icatu) at the highest temperature; B) quantitative and
qualitative modifications in GL (monogalactosyldiacylglycerol, MGDG; digalactosyldiacylglycerol, DGDG), PL
(phosphatidylcholine, PC; phosphatidylglycerol, PG), and SL (sulfoquinovosyldiacylglycerol, SQDG) classes,
prompted by heat, elevated [CO2], and, especially, the interaction, in CL153 and Icatu. Overall membrane enrichment
with MGDG and DGDG as a result of heat and [CO2] interaction in these genotypes, but at the highest temperature
only in Icatu the high [CO2] maintained greater contents and unsaturation values of these GLs than in the
380-plants. C) Among PL classes, PG seems to play an active role in heat acclimation of C. arabica genotypes,
increasing in 700-plants at 42/34 °C. Globally, Icatu often showed changes closer to those of heat tolerant cv. CL153
than to cv. IPR108. Overall, lipid profile adjustments in chloroplast membranes, from TFAs bulk until FA unsaturation
within each class, are expected to contribute to long-term acclimation to climate changes in coffee plant
Stress cross-response of the antioxidative system promoted by superimposed drought and cold conditions in Coffea spp.
Publication . Ramalho, José C.; Rodrigues, Ana P.; Lidon, Fernando C.; Marques, Luís M.C.; Leitão, A.Eduardo; Fortunato, Ana S.; Pais, Isabel P.; Silva, Maria J.; Scotti-Campos, Paula; Lopes, António; Reboredo, F.H.; Ribeiro-Barros, Ana I.
The understanding of acclimation strategies to low temperature and water availability is decisive to ensure coffee crop
sustainability, since these environmental conditions determine the suitability of cultivation areas. In this context, the impacts of
single and combined exposure to drought and cold were evaluated in three genotypes of the two major cropped species, Coffea
arabica cv. Icatu, Coffea canephora cv. Apoatã, and the hybrid Obatã. Crucial traits of plant resilience to environmental stresses
have been examined: photosynthesis, lipoperoxidation and the antioxidant response. Drought and/or cold promoted leaf
dehydration, which was accompanied by stomatal and mesophyll limitations that impaired leaf C-assimilation in all genotypes.
However, Icatu showed a lower impact upon stress exposure and a faster and complete photosynthetic recovery. Although
lipoperoxidation was increased by drought (Icatu) and cold (all genotypes), it was greatly reduced by stress interaction, especially in
Icatu. In fact, although the antioxidative system was reinforced under single drought and cold exposure (e.g., activity of enzymes as
Cu,Zn-superoxide dismutase, ascorbate peroxidase, APX, glutathione reductase and catalase, CAT), the stronger increases were
observed upon the simultaneous exposure to both stresses, which was accompanied with a transcriptional response of some
genes, namely related to APX. Complementary, non-enzyme antioxidant molecules were promoted mostly by cold and the stress
interaction, including α-tocopherol (in C. arabica plants), ascorbate (ASC), zeaxanthin, and phenolic compounds (all genotypes). In
general, drought promoted antioxidant enzymes activity, whereas cold enhanced the synthesis of both enzyme and non-enzyme
antioxidants, the latter likely related to a higher need of antioxidative capability when enzyme reactions were probably quite
repressed by low temperature. Icatu showed the wider antioxidative capability, with the triggering of all studied antioxidative
molecules by drought (except CAT), cold, and, particularly, stress interaction (except ASC), revealing a clear stress cross-tolerance.
This justified the lower impacts on membrane lipoperoxidation and photosynthetic capacity under stress interaction conditions,
related to a better ROS control. These findings are also relevant to coffee water management, showing that watering in the cold
season should be largely avoided
Unidades organizacionais
Descrição
Palavras-chave
Contribuidores
Financiadores
Entidade financiadora
Fundação para a Ciência e a Tecnologia
Programa de financiamento
5876
Número da atribuição
UID/GEO/04035/2013