Primary metabolism components of seeds from Brazilian Amazon tree species

The contents of the main components of the primary metabolism (soluble sugars, starch, proteins, oils, fatty acids) and minerals (P, Ca, Mg, K, Fe, Zn, Mn, Cu) were characterized in seeds of five Brazilian Amazon tree species (Andira parviflora, Bertholletia excelsa, Helicostylis tomentosa, Hymenaea parviflora, and Parkia pendula). Soluble sugar contents were high in P. pendula seeds (14%), whereas starch predominated in A. parviflora seeds (58.7%). A. parviflora and H. parviflora seeds were rich in proteins (35.1% and 32.4%, respectively). The oil contents ranged from 1.4% in A. parviflora to 70.7% in B. excelsa. Only B. excelsa and P. pendula seeds may be considered oilseeds, with 70.7% and 28.4% oil, respectively. The fatty acid compositions showed high proportions of unsaturated fatty acids, mainly oleic and linoleic acids, regardless of the species. B. excelsa and P. pendula also showed high amounts of P, Mg, K and Zn

Seeds of Amazonian Fabaceae as a source of new lectins

Seeds from fifty native Amazonian Fabaceae species (representing subfamilies Caesalpinioideae, Mimosoideae and Faboideae) were screened for the presence of new lectins. Their crude protein extracts were assayed for hemagglutinating activity (HA). The protein fractions of Anadenanthera peregrina, Dimorphandra caudata, Ormosia lignivalvis and Swartzia laevicarpa exhibited HA, and this activity was inhibited by galactose or lactose but not by glucose or mannose. The crude extract of S. laevicarpa exhibited HA activity only after ion exchange chromatography, and its lectin was further purified by affinity chromatography on immobilized lactose. Despite the large number of lectins that have been reported in leguminous plants, this is the first description of lectins in the genera Anadenanthera, Dimorphandra and Ormosia. The study of lectins from these genera and from Swartzia will contribute to the understanding of the evolutionary relationships of legume lectins in terms of their protein processing properties and structures

Physiological and anatomical characteristics of leaves of two clones of guarana

The objective of this work was to analyze gas exchange, photosynthetic characteristics, photochemical efficiency of photosystem II and anatomical characteristics of young plant leaves of two guarana (Paullinia cupana) clones (BRS-CG372RC and BRS-CG611RL) growing under open field. The variables of gas exchange and fluorescence of chlorophyll a were evaluated in mature leaves. The values of photosynthesis and transpiration found for BRS-CG372RC were 27% greater and 80% lesser than values found for BRS-CG611RL, respectively. The values of stomatal conductance found for the clones BRS-CG372RC and BRS-CG611RL were in the order of 224 and 614 mmol mm-2 s-1, respectively. The values of photorespiration, rate of carboxylation and rate electron transport were greater in BRS-CG372RC. The clone BRS-CG372RC exhibited stomatal density 26% greater than BRS-CG611RL. However, the area of ostiolar opening was 42% greater in BRS-CG611RL. The values of the water use efficiency in BRS-CG372RC were 134% greater than in BRS-CG611RL. High stomatal density and low stomatal conductance can be important characteristics in the selection of the clones with a good ability to assimilate carbon and optimize the use of water

Lectin genes and their mature proteins: Still an exciting matter, as revealed by biochemistry and bioinformatics analyses of newly reported proteins

Two new lectins were purified through affinity chromatography after crude extract preparation under high ionic strength. The hemagglutinating activity of these lectins from the seeds of the legumes Dioclea bicolor (DBL) and Deguelia scandens (DSL) was inhibited by galactose and glucose, respectively, and the molecular masses were estimated at 24 and 22kDa (via SDS-PAGE), respectively. The alignment of internal peptides of DBL (MS/MS) with known protein sequences revealed similarity to other legume lectins. The N-terminal amino acid sequence of DSL also aligned with legume lectins. Cross-similarities among the two studied lectins were observed only after sequence permutation. More than a dozen lectins have been reported for the genus Dioclea but none that recognize galactose. DSL is the first lectin reported for the Deguelia genus in the tribe Millettieae. With the aid of bioinformatics tools and searches for genome/transcriptome information about closely related sequences, new lectin members of Millettieae were also identified. Electrophoresis profiling and amino acid sequence analysis suggested that DBL-Gal and DSL do not undergo post-transcriptional ConA-like circular permutation. Molecular modeling of the deduced amino acid sequences of the Millettieae lectins suggested that the overall folding of the monomeric structures of legume lectins is conserved. This and other recent studies highlight native plants of the Amazon as renewed sources of lectins. © 2015 Elsevier Ltd

Fungicidal properties and insights on the mechanisms of the action of volatile oils from Amazonian Aniba trees

The Amazonian Aniba species are world-renowned for their essential oils (EOs). The molecules derived from EOs have been intensively investigated in regards to their potential for disease control in plants. The aim of this study was to investigate the antifungal properties of Aniba canelilla EO (ACEO) and Aniba parviflora EO (APEO) when used against eight phytopathogenic fungi. Gas chromatography-mass spectrometry (GC–MS) analysis of oils showed that 1-nitro-2-phenylethane (∼80%) and linalool (∼40%) are the major compounds in ACEO and APEO, respectively. The ACEO and APEO treatments displayed remarkable antifungal effects against Aspergillus flavus, Aspergillus niger, Fusarium oxysporum, Fusarium solani, Alternaria alternata, Colletotrichum gloeosporioides, Colletotrichum musae and Colletotrichum guaranicola, for which the IC50 values ranged from 0.05 to 0.28 μL mL−1 and 0.17 to 0.63 μL mL−1, respectively. Furthermore, the oil caused the inhibition of conidial germination by at least 83% for ACEO and 78% for APEO. The ACEO and APEO at 5 μL mL−1 induced leakage of nucleic acids and protein, suggesting that inhibition could be linked to the breakdown of membrane integrity of the conidia. In addition, the detection of fluorescent dye propidium iodide (PI) on F. solani conidia treated with ACEO and APEO indicates damage on the conidia cytoplasmic membrane. The findings of this study may be of biotechnological interest for the development of new plant protection products, with the advantage of being less harmful than the agrochemicals currently available. © 2019 Elsevier B.V

Leaf water potential, gas exchange and chlorophyll a fluorescence in acariquara seedlings (Minquartia guianensis Aubl.) under water stress and recovery

The physiological performance of acariquara (Minquartia guianensis) seedlings submitted to water deficit and the recovery of physiological parameters during rehydration were investigated in a greenhouse experiment. The analyzed parameters were: leaf water potential, gas exchange and chlorophyll a fluorescence. After thirty-five days, non-irrigated plants exhibited a leaf water potential 70 % lower compared to control plants (irrigated daily) and the stomatal conductance reached values close to zero, inducing a severe decrease in gas exchange (photosynthesis and transpiration). Six days after the beginning of the rehydration of drought-stressed plants, the results demonstrated that water stress did not irreversibly affect gas exchange and quantum efficiency of photosystem II (PSII) in M. guianensis seedlings, since four to six days after rehydration the plants exhibited total recovery of the photosynthetic apparatus. We conclude that M. guianensis presented good tolerance to water stress and good capacity to recover the physiological performance related to leaf water status, photosynthesis and photochemical efficiency of PS II under hydric stress, suggesting substantial physiological plasticity during the juvenile phase for this tree species

Variability and antifungal activity of volatile compounds from Aniba rosaeodora Ducke, harvested from Central Amazonia in two different seasons

Finding new applications for the essential oils (EOs) of the branches and leaves of Aniba species represents a valuable strategy for the adoption of correct management of the crown and to help make Aniba plantations economically valuable. We report here the antifungal activity of the EO from Aniba rosaeodora Ducke against plant pathogenic fungi. The present study investigated the chemical variability and antifungal effect of EO from A. rosaeodora harvested during the wet and dry seasons in the Amazon region. The volatile content obtained from the aerial parts by hydro-distillation was analyzed for its chemical composition by gas chromatography–mass spectrometry (GC–MS). Furthermore, a broth and agar dilution method was used to determine the antifungal activity against phytopathogens. Quantitative and qualitative variations in composition among the EOs were detected. Linalool was a major component in the oil of leaves and branches from both periods. Quantification using an external standard showed a higher concentration of linalool in the wet season (74.4 ± 3.9% in leaves and 81.8 ± 5.7% in branches) than in the dry season (47.5 ± 2.2 in leaves and 49.2 ± 1.6% in branches). The EOs were toxic to all phytopathogens analyzed, displaying superior inhibitory activity toward Colletotrichum guaranicola, with inhibition zone diameters ranging from 15.2 ± 1.2 to 21.3 ± 1.7 mm and IC50 values of 0.578 to 2.094 μL mL−1. Interestingly, the EOs collected during the wet season were effective in reducing the vegetative growth of phytopathogens, providing evidence for the involvement of linalool in the inhibitory effect. © 2018 Elsevier B.V

Growth, photosynthesis and stress indicators in young rosewood plants (Aniba rosaeodora Ducke) under different light intensities

Aniba rosaeodora is an Amazonian tree species that belongs to the family Lauraceae. Due to intense exploitation for extraction of essential oils (mainly linalol), A. rosaeodora is now considered an endangered species. On the other hand, there is little information about its ecophysiology which would be useful to support future forest planting programs. Hence, the effect of different light intensities on the growth and photosynthetic characteristics of young plants of A. rosaeodora was studied. Nine-month-old plants were subjected to four light treatments (T1=10 a 250 μmol.m-2.s-1 / control; T2=500 to 800, T3=700 to 1000 and T 4=1300 to 1800 μmol.m-2.s-1 / full sunlight). Allometric variables, gas exchange, contents of pigments and chlorophyll a fluorescence were analysed. As to the relative growth rates, it was found that plants of A. rosaeodora showed higher biomass accumulation when grown under intermediary irradiance conditions (T2). The best photosynthetic performance was achieved under conditions of T3. When growth was correlated with photosynthesis, it was found that plants under treatments T2 and T3 presented better responses in comparison with the lowest (T1) and highest (T4) light extremes. The highest pigment contents were obtained for plants in the shade (T1) and the lowest for those exposed to full sunlight (T 4). The photochemical efficiency of photosystem II (F v/Fm) was found that only plants in the shade treatment (T1) presented no stress from high irradiance. These findings suggest that both treatments (T1 and T4) altered the function of the A. rosaeodora plants, inhibiting photosynthesis and growth. Plants of A. rosaeodora developed photo-protection mechanisms under full sunlight. However, the species presented better photosynthetic response and biomass gain under intermediary irradiance conditions, displaying relative physiological plasticity, during the seedling phase