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- Intrinsic non-stomatal resilience to drought of the photosynthetic apparatus in Coffea spp. is strengthened by elevated air [CO2]Publication . JN; Rodrigues, Ana P.; Lidon, Fernando C.; P. Pais, Isabel; Marques, Isabel; Gouveia, Duarte; ARMENGAUD, Jean; Silva, Maria J.; Martins, Sónia; Semedo, Magda C.; Dubberstein, Danielly; Partelli, Fábio Luiz; Reboredo, Fernando H.; Scotti-Campos, Paula; Ribeiro-Barros, Ana I; DaMatta, Fabio; Ramalho, José C.Growing water restrictions associated with climate changes constitute daunting challenges to crop performance. This study unveils the impacts of moderate (MWD) or severe (SWD) water deficit, and their interaction with air [CO2], on the photosynthetic apparatus of Coffea canephora Pierre ex A. Froehner cv. Conilon Clone 153 (CL153) and Coffea arabica L. cv. Icatu. Seven year-old potted plants grown under 380 (aCO(2)) or 700 mu l l (-1) (eCO(2)) [CO2] gradually reached predawn water potentials between -1.6 and -2.1 MPa (MWD), and below -3.5 MPa (SWD). Under drought, stomata closure was chiefly related to abscisic acid (ABA) rise. Increasing drought severity progressively affected gas exchange and fluorescence parameters in both genotypes, with non-stomatal limitations becoming gradually dominating, especially regarding the photochemical and biochemical components of CL153 SWD plants. In contrast, Icatu plants were highly tolerant to SWD, with minor, if any, negative impacts on the potential photosynthetic functioning and components (e.g., A(max), F-v/F-m, electron carriers, photosystems (PSs) and ribulose-1,5-bisphosphate carboxylase oxygenase (RuBisCO) activities). Besides, drought-stressed Icatu plants displayed increased abundance of a large set of proteins associated with the photosynthetic apparatus (PSs, light-harvesting complexes, cyclic electron flow, RuBisCO activase) regardless of [CO2]. Single eCO(2) did not promote stomatal and photosynthetic down-regulation in both genotypes. Instead, eCO(2) increased photosynthetic performance, moderately reinforced photochemical (PSs activity, electron carriers) and biochemical (RuBisCO, ribulose-5-phosphate kinase) components, whereas photoprotective mechanisms and protein abundance remained mostly unaffected. In both genotypes, under MWD, eCO(2) superimposition delayed stress severity and promoted photosynthetic functioning with lower energy dissipation and PSII impacts, whereas stomatal closure was decoupled from increases in ABA. In SWD plants, most impacts on the photosynthetic performance were reduced by eCO(2), especially in the moderately drought affected CL153 genotype, although maintaining RuBisCO as the most sensitive component, deserving special breeder's attention to improve coffee sustainability under future climate scenarios.
- Resilient and sensitive key points of the photosynthetic machinery of coffea spp. to the single and superimposed exposure to severe drought and heat stressesPublication . Dubberstein, Danielly; Lidon, Fernando C.; Rodrigues, Ana P.; Semedo, José N.; Marques, Isabel; Rodrigues, Weverton P.; Gouveia, Duarte; ARMENGAUD, Jean; Semedo, Magda C.; Martins, Sónia; Simoes-Costa, Maria C.; Moura, Isabel; Pais, Isabel P.; Scotti-Campos, Paula; Partelli, Fábio Luiz; E, Campostrini; Ribeiro-Barros, Ana I.; DaMatta, Fabio; Ramalho, José C.This study unveils the single and combined drought and heat impacts on the photosynthetic performance ofCoffea arabicacv. Icatu andC. canephoracv. Conilon Clone 153 (CL153). Well-watered (WW) potted plants were gradually submitted to severe water deficit (SWD) along 20 days under adequate temperature (25/20 degrees C, day/night), and thereafter exposed to a gradual temperature rise up to 42/30 degrees C, followed by a 14-day water and temperature recovery. Single drought affected all gas exchanges (includingA(max)) and most fluorescence parameters in both genotypes. However, Icatu maintainedF(v)/F(m)and RuBisCO activity, and reinforced electron transport rates, carrier contents, and proton gradient regulation (PGR5) and chloroplast NADH dehydrogenase-like (NDH) complex proteins abundance. This suggested negligible non-stomatal limitations of photosynthesis that were accompanied by a triggering of protective cyclic electron transport (CEF) involving both photosystems (PSs). These findings contrasted with declines in RuBisCO and PSs activities, and cytochromes (b(559),f,b(563)) contents in CL153. Remarkable heat tolerance in potential photosynthetic functioning was detected in WW plants of both genotypes (up to 37/28 degrees C or 39/30 degrees C), likely associated with CEF in Icatu. Yet, at 42/30 degrees C the tolerance limit was exceeded. ReducedA(max)and increasedC(i)values reflected non-stomatal limitations of photosynthesis, agreeing with impairments in energy capture (F(0)rise), PSII photochemical efficiency, and RuBisCO and Ru5PK activities. In contrast to PSs activities and electron carrier contents, enzyme activities were highly heat sensitive. Until 37/28 degrees C, stresses interaction was largely absent, and drought played the major role in constraining photosynthesis functioning. Harsher conditions (SWD, 42/30 degrees C) exacerbated impairments to PSs, enzymes, and electron carriers, but uncontrolled energy dissipation was mitigated by photoprotective mechanisms. Most parameters recovered fully between 4 and 14 days after stress relief in both genotypes, although some aftereffects persisted in SWD plants. Icatu was more drought tolerant, with WW and SWD plants usually showing a faster and/or greater recovery than CL153. Heat affected both genotypes mostly at 42/30 degrees C, especially in SWD and Icatu plants. Overall, photochemical components were highly tolerant to heat and to stress interaction in contrast to enzymes that deserve special attention by breeding programs to increase coffee sustainability in climate change scenarios.
- Next-generation proteomics reveals a greater antioxidative response to drought in Coffea arabica than in Coffea canephoraPublication . Marques, Isabel; Gouveia, Duarte; Gaillard, Jean-Charles; Martins, Sónia; Semedo, Magda C.; Lidon, Fernando C.; DaMatta, Fabio; Ribeiro, Ana; ARMENGAUD, Jean; Ramalho, José C.Drought is a major threat to coffee, compromising the quality and quantity of its production. We have analyzed the core proteome of 18 Coffea canephora cv. Conilon Clone 153 and C. arabica cv. Icatu plants and assessed their responses to moderate (MWD) and severe (SWD) water deficits. Label-free quantitative shotgun proteomics identified 3000 proteins in both genotypes, but less than 0.8% contributed to ca. 20% of proteome biomass. Proteomic changes were dependent on the severity of drought, being stronger under SWD and with an enrolment of different proteins, functions, and pathways than under MWD. The two genotypes displayed stress-responsive proteins under SWD, but only C. arabica showed a higher abundance of proteins involved in antioxidant detoxification activities. Overall, the impact of MWD was minor in the two genotypes, contrary to previous studies. In contrast, an extensive proteomic response was found under SWD, with C. arabica having a greater potential for acclimation/resilience than C. canephora. This is likely supported by a wider antioxidative response and an ability to repair photosynthetic structures, being crucial to develop new elite genotypes that assure coffee supply under water scarcity levels.