IBA and melatonin increase trigonelline and caffeine during the induction and initiation of adventitious roots in Coffea arabica L. cuttings.

Caffeine and trigonelline are found in Coffea arabica, and show antioxidant roles and growth and development functions. However, there are no reports on trigonelline and caffeine in relation to coffee rooting. The aim was to evaluate the impact of application of indole-3-butyric acid (IBA) and melatonin on caffeine and trigonelline at different stages of adventitious rooting in cuttings. In addition, to study the correlation between these metabolites and H2O2, phenols, and antioxidant enzymes. Four treatments (Control, melatonin 21 µM (M21), melatonin 43 µM (M43), and IBA 7380 µM (IBA)) were used, with four replications. The growth and biochemical parameters of the antioxidant system were performed in induction, initiation, and extension rooting stages. Higher concentrations of trigonelline and caffeine quantified in the induction and initiation stages were positively correlated with higher percentage of rooted cuttings. Trigonelline and caffeine were positively correlated with H2O2 in all stages of development of adventitious roots. The correlations of trigoneline and caffeine with phenols and antioxidant enzymes reveal different profiles, depending on the phases. The results indicate that IBA and melatonin increase trigonelline and caffeine during the induction and initiation of adventitious roots in Coffea arabica cuttings, which is correlated with a higher percentage of rooted cuttings.

Metabolic Pathway Reconstruction Indicates the Presence of Important Medicinal Compounds in Coffea Such as L-DOPA.

The use of transcriptomic data to make inferences about plant metabolomes is a useful tool to help the discovery of important compounds in the available biodiversity. To unveil previously undiscovered metabolites of Coffea, of phytotherapeutic and economic value, we employed 24 RNAseq libraries. These libraries were sequenced from leaves exposed to a diverse range of environmental conditions. Subsequently, the data were meticulously processed to create models of putative metabolic networks, which shed light on the production of potential natural compounds of significant interest. Then, we selected one of the predicted compounds, the L-3,4-dihydroxyphenylalanine (L-DOPA), to be analyzed by LC-MS/MS using three biological replicates of flowers, leaves, and fruits from Coffea arabica and Coffea canephora. We were able to identify metabolic pathways responsible for producing several compounds of economic importance. One of the identified pathways involved in isoquinoline alkaloid biosynthesis was found to be active and producing L-DOPA, which is a common product of POLYPHENOL OXIDASES (PPOs, EC 1.14.18.1 and EC 1.10.3.1). We show that coffee plants are a natural source of L-DOPA, a widely used medicine for treatment of the human neurodegenerative condition called Parkinson's disease. In addition, dozens of other compounds with medicinal significance were predicted as potential natural coffee products. By further refining analytical chemistry techniques, it will be possible to enhance the characterization of coffee metabolites, enabling a deeper understanding of their properties and potential applications in medicine.

Potassium Phosphite Activates Components Associated with Constitutive Defense Responses in Coffea arabica Cultivars.

Phosphites have been used as inducers of resistance, activating the defense of plants and increasing its ability to respond to the invasion of the pathogen. However, the mode of action of phosphites in defense responses has not yet been fully elucidated. The objective of this study was to evaluate the effect of potassium phosphite (KPhi) in coffee cultivars with different levels of resistance to rust to clarify the mechanism by which KPhi activates the constitutive defense of plants. To this end, we studied the expression of genes and the activity of enzymes involved in the defense pathway of salicylic acid (SA) and reactive oxygen species (ROS), in addition to the levels of total soluble phenolic compounds and soluble lignin. Treatment with KPhi induced constitutive defense responses in cultivars resistant and susceptible to rust. The results suggest that KPhi acts in two parallel defense pathways, SA and ROS, which are essential for the induction of systemic acquired resistance (SAR) when activated simultaneously. The activation of the mechanisms associated with defense routes demonstrates that KPhi is a potential inducer of resistance in coffee plants.

Potential of rust-resistant arabica coffee cultivars for specialty coffee production

Rust is the main disease affecting Coffea arabica, the most economically important coffee species. The objective of this study was to analyze C. arabicacultivars with different levels of rust resistance, including bean size, raw bean appearance, finalsensory scores (FSS), and aromaand taste nuances of the coffee cup. The experiment was designed in randomized blocks (RBD) with three replications and 20 treatments (cultivars), totaling 60 experimental plots. The rust-susceptible cultivars IPR 100, Rubi MG 1192, and Topázio MG 1190 were compared with 17 rust-resistant cultivars.Cultivars IPR 103, MGS Aranãs, and SaíraII presented the highest percentages of high sieves, highest scores of raw bean appearance, and low percentages of mocha-type beans. All cultivars had FSS above 82 and were classified as specialty coffees. The cultivars with the highest FSS (Arara and Catiguá MG2) showed a greater diversity of coffee cup aroma and flavor nuances. Rust-resistant Arabica coffee cultivars are promising for the physical quality of beans and have potential for the specialty coffee market.

Genome-wide association study for resistance to Pseudomonas syringae pv. garcae in Coffea arabica.

Bacteria halo blight (BHB), a coffee plant disease caused by Pseudomonas syringae pv. garcae, has been gaining importance in producing mountain regions and mild temperatures areas as well as in coffee nurseries. Most Coffea arabica cultivars are susceptible to this disease. In contrast, a great source of genetic diversity and resistance to BHB are found in C. arabica Ethiopian accessions. Aiming to identify quantitative trait nucleotides (QTNs) associated with resistance to BHB and the influence of these genomic regions during the domestication of C. arabica, we conducted an analysis of population structure and a Genome-Wide Association Study (GWAS). For this, we used genotyping by sequencing (GBS) and phenotyping for resistance to BHB of a panel with 120 C. arabica Ethiopian accessions from a historical FAO collection, 11 C. arabica cultivars, and the BA-10 genotype. Population structure analysis based on single-nucleotide polymorphisms (SNPs) markers showed that the 132 accessions are divided into 3 clusters: most wild Ethiopian accessions, domesticated Ethiopian accessions, and cultivars. GWAS, using the single-locus model MLM and the multi-locus models mrMLM, FASTmrMLM, FASTmrEMMA, and ISIS EM-BLASSO, identified 11 QTNs associated with resistance to BHB. Among these QTNs, the four with the highest values of association for resistance to BHB are linked to g000 (Chr_0_434_435) and g010741 genes, which are predicted to encode a serine/threonine-kinase protein and a nucleotide binding site leucine-rich repeat (NBS-LRR), respectively. These genes displayed a similar transcriptional downregulation profile in a C. arabica susceptible cultivar and in a C. arabica cultivar with quantitative resistance, when infected with P. syringae pv. garcae. However, peaks of upregulation were observed in a C. arabica cultivar with qualitative resistance, for both genes. Our results provide SNPs that have potential for application in Marker Assisted Selection (MAS) and expand our understanding about the complex genetic control of the resistance to BHB in C. arabica. In addition, the findings contribute to increasing understanding of the C. arabica domestication history.

Genome-Wide Identification, Characterization, and Comparative Analysis of NLR Resistance Genes in Coffea spp.

The largest family of disease resistance genes in plants are nucleotide-binding site leucine-rich repeat genes (NLRs). The products of these genes are responsible for recognizing avirulence proteins (Avr) of phytopathogens and triggering specific defense responses. Identifying NLRs in plant genomes with standard gene annotation software is challenging due to their multidomain nature, sequence diversity, and clustered genomic distribution. We present the results of a genome-wide scan and comparative analysis of NLR loci in three coffee species (Coffea canephora, Coffea eugenioides and their interspecific hybrid Coffea arabica). A total of 1311 non-redundant NLR loci were identified in C. arabica, 927 in C. canephora, and 1079 in C. eugenioides, of which 809, 562, and 695 are complete loci, respectively. The NLR-Annotator tool used in this study showed extremely high sensitivities and specificities (over 99%) and increased the detection of putative NLRs in the reference coffee genomes. The NLRs loci in coffee are distributed among all chromosomes and are organized mostly in clusters. The C. arabica genome presented a smaller number of NLR loci when compared to the sum of the parental genomes (C. canephora, and C. eugenioides). There are orthologous NLRs (orthogroups) shared between coffee, tomato, potato, and reference NLRs and those that are shared only among coffee species, which provides clues about the functionality and evolutionary history of these orthogroups. Phylogenetic analysis demonstrated orthologous NLRs shared between C. arabica and the parental genomes and those that were possibly lost. The NLR family members in coffee are subdivided into two main groups: TIR-NLR (TNL) and non-TNL. The non-TNLs seem to represent a repertoire of resistance genes that are important in coffee. These results will support functional studies and contribute to a more precise use of these genes for breeding disease-resistant coffee cultivars.

LysM receptors in Coffea arabica: Identification, characterization, and gene expression in response to Hemileia vastatrix.

Pathogen-associated molecular patterns (PAMPs) are recognized by pattern recognition receptors (PRRs) localized on the host plasma membrane. These receptors activate a broad-spectrum and durable defense, which are desired characteristics for disease resistance in plant breeding programs. In this study, candidate sequences for PRRs with lysin motifs (LysM) were investigated in the Coffea arabica genome. For this, approaches based on the principle of sequence similarity, conservation of motifs and domains, phylogenetic analysis, and modulation of gene expression in response to Hemileia vastatrix were used. The candidate sequences for PRRs in C. arabica (Ca1-LYP, Ca2-LYP, Ca1-CERK1, Ca2-CERK1, Ca-LYK4, Ca1-LYK5 and Ca2-LYK5) showed high similarity with the reference PRRs used: Os-CEBiP, At-CERK1, At-LYK4 and At-LYK5. Moreover, the ectodomains of these sequences showed high identity or similarity with the reference sequences, indicating structural and functional conservation. The studied sequences are also phylogenetically related to the reference PRRs described in Arabidopsis, rice, and other plant species. All candidates for receptors had their expression induced after the inoculation with H. vastatrix, since the first time of sampling at 6 hours post-inoculation (hpi). At 24 hpi, there was a significant increase in expression, for most of the receptors evaluated, and at 48 hpi, a suppression. The results showed that the candidate sequences for PRRs in the C. arabica genome display high homology with fungal PRRs already described in the literature. Besides, they respond to pathogen inoculation and seem to be involved in the perception or signaling of fungal chitin, acting as receptors or co-receptors of this molecule. These findings represent an advance in the understanding of the basal immunity of this species.

Screening coffee genotypes for brown eye spot resistance in Brazil.

Several researchers have attempted to develop coffee plants that are resistant to brown eye spot (BES); however, no coffee cultivars are resistant to the disease. In the present study, a blend of strains from Cercospora coffeicola was inoculated into 19 Brazilian commercial cultivars and 41 accessions from the Germplasm Collection of Minas Gerais to evaluate the genetic resistance ability within the population and select superior genotypes for the breeding program. After predicting the genotypic values of the estudied material, the evaluations number necessary for selecting genotypes with accuracy and efficiency was determined based on the data of severity to BES. The action of defense mechanisms plant was also investigated by assessing the levels of total soluble phenolic compounds and soluble lignin in contrasting genotypes for disease susceptibility. Based on the results, the accession MG 1207 Sumatra, had an intrinsic genetic capacity to maintain low levels of severity to BES. The genotype MG 1207 Sumatra can substantially contribute to the development of new cultivars, which may lead to the reduced use of pesticides. According to the accuracy and efficiency results obtained, four evaluations BES severity are sufficient to achieve accuracy, providing expressive genetic gains. Finally, the levels of lignin and phenolic compounds were not found to be associated with the resistance of coffee genotypes to BES.

Production and characterization of a new distilled beverage from green coffee seed residue.

This study evaluated green coffee seed residue (GCSR) as an alternative substrate for producing distilled beverages. Two proportions of GCSR, 10% and 20% (w/v), were fermented and distilled in a copper alembic still. The spirits were characterized by GC-FID, HS-SPME GC-MS, and sensory analysis by trained panelists. Most of the 62 identified volatile compounds were affected by the GCSR concentration. Total terpenes, higher alcohols, and acetals showed the highest concentrations in the 10% GCSR spirit. Esters, acetates, and aldehydes were most abundant in the 20% GCSR. In the sensory analysis, the 10% GCSR spirit was characterized by floral, dairy, and almond aromas, while the 20% GCSR spirit was embodied coffee, vegetable, hazelnut, cooked cabbage, and nut descriptors. The results demonstrate the potential of GCSR as a substrate for producing coffee spirits with chemical and sensory qualities, with the 10% GCSR being the better option for fermentation.

Constitutive Defense Strategy of Coffee Under Field Conditions: A Comparative Assessment of Resistant and Susceptible Cultivars to Rust.

Coffea arabica is the most economically important coffee species worldwide. However, its production is severely limited by diseases such as rust. The mechanisms underlying constitutive defense responses in coffee are still poorly understood, compared with induced defense mechanisms. We aimed to characterize constitutive defense responses of thirteen cultivars of C. arabica. Cultivars were classified under field conditions according to the level of resistance to rust: resistant (R), moderately resistant (MR), and susceptible (S). Based on this classification, the stability of eight reference genes (RGs) was evaluated. The most stable RGs were EF1α, APT1, and 24S. We also evaluated the expression of CaWRKY1, CaPAL1, CaCAD1, and CaPOX1, and activities of PAL, CAD, and POX, which are involved in lignin biosynthesis, and leaf content of total phenolic compounds and lignin. Gene expression and enzymatic activity were not correlated with defense metabolites in the R cultivar group but showed a negative correlation with phenolic compounds in MR cultivars. Cultivar S showed positive correlations of gene expression and enzyme activity with phenolic compounds. These results may assist coffee breeding programs regarding selection of genotypes and in optimization of rust resistance.

Chemical Composition, Production of Secondary Metabolites and Antioxidant Activity in Coffee Cultivars Susceptible and Partially Resistant to Bacterial Halo Blight.

Coffee production is one of the main agricultural activities in Brazil, and several coffee cultivars with disease resistance have already been developed. The secondary metabolites produced by plants are closely associated with defense strategies, and the resistance of coffee cultivars to bacterial halo blight (BHB) can be related to these compounds. Therefore, this study aims to compare a partially resistant coffee cultivar (Iapar-59) and a susceptible cultivar (Mundo Novo 376/4) to BHB (Pseudomonas syringae pv. garcae) in relation to the chemical composition and antioxidant activity of the leaf extracts. In addition, this study determined the total phenolic and flavonoid contents and phenolic profiles of the Iapar-59 leaf extracts of plants inoculated with P. syringae pv. garcae. The Iapar-59 extract showed a higher content of phenolic compounds and flavonoids than the Mundo Novo 376/4 extract. Both cultivars contained gallic, chlorogenic and caffeic acids; however, the highest contents were quantified in the Iapar-59 cultivar. The leaf extracts from the Iapar-59 cultivar exhibited higher antioxidant activity. Higher concentrations of gallic, caffeic and chlorogenic acids and the presence of vanillin were detected in the extract of cultivar Iapar-59 inoculated with P. syringae pv. garcae.

Primary Metabolism Is Distinctly Modulated by Plant Resistance Inducers in Coffea arabica Leaves Infected by Hemileia vastatrix.

Epidemics of coffee leaf rust (CLR) leads to great yield losses and huge depreciation of coffee marketing values, if no control measures are applied. Societal expectations of a more sustainable coffee production are increasingly imposing the replacement of fungicide treatments by alternative solutions. A protection strategy is to take advantage of the plant immune system by eliciting constitutive defenses. Based on such concept, plant resistance inducers (PRIs) have been developed. The Greenforce CuCa formulation, similarly to acibenzolar-S-methyl (ASM), shows promising results in the control of CLR (Hemileia vastatrix) in Coffea arabica cv. Mundo Novo. The molecular mechanisms of PRIs action are poorly understood. In order to contribute to its elucidation a proteomic, physiological (leaf gas-exchange) and biochemical (enzymatic) analyses were performed. Coffee leaves treated with Greenforce CuCa and ASM and inoculation with H. vastatrix were considered. Proteomics revealed that both PRIs lead to metabolic adjustments but, inducing distinct proteins. These proteins were related with photosynthesis, protein metabolism and stress responses. Greenforce CuCa increased photosynthesis and stomatal conductance, while ASM caused a decrease in these parameters. It was further observed that Greenforce CuCa reinforces the redox homeostasis of the leaf, while ASM seems to affect preferentially the secondary metabolism and the stress-related proteins. So, the PRIs prepare the plant to resist CLR but, inducing different defense mechanisms upon pathogen infection. The existence of a link between the primary metabolism and defense responses was evidenced. The identification of components of the plant primary metabolism, essential for plant growth and development that, simultaneously, participate in the plant defense responses can open new perspectives for plant breeding programs.

Genome sequencing and transcript analysis of Hemileia vastatrix reveal expression dynamics of candidate effectors dependent on host compatibility.

Coffee leaf rust caused by the fungus Hemileia vastatrix is one of the most important leaf diseases of coffee plantations worldwide. Current knowledge of the H. vastatrix genome is limited and only a small fraction of the total fungal secretome has been identified. In order to obtain a more comprehensive understanding of its secretome, we aimed to sequence and assemble the entire H. vastatrix genome using two next-generation sequencing platforms and a hybrid assembly strategy. This resulted in a 547 Mb genome of H. vastatrix race XXXIII (Hv33), with 13,364 predicted genes that encode 13,034 putative proteins with transcriptomic support. Based on this proteome, 615 proteins contain putative secretion peptides, and lack transmembrane domains. From this putative secretome, 111 proteins were identified as candidate effectors (EHv33) unique to H. vastatrix, and a subset consisting of 17 EHv33 genes was selected for a temporal gene expression analysis during infection. Five genes were significantly induced early during an incompatible interaction, indicating their potential role as pre-haustorial effectors possibly recognized by the resistant coffee genotype. Another nine genes were significantly induced after haustorium formation in the compatible interaction. Overall, we suggest that this fungus is able to selectively mount its survival strategy with effectors that depend on the host genotype involved in the infection process.

Alterations in antioxidant metabolism in coffee leaves infected by Cercospora coffeicola / Alterações no metabolismo antioxidante de folhas de cafeeiro infectadas por Cercospora coffeicola

ABSTRACT: Brown eye spot (BE) caused by Cercospora coffeicola is the main disease of coffee crop. A variation in symptoms of BE has been reported in the field, raising suspicion of occurrence of new species. However, information about coffee- C. coffeicola interaction is still limited. This research aimed to determine the difference between antioxidant metabolism of coffee plants cultivar Mundo Novo inoculated with a strain isolated from a common BE lesion (CML 2984) and a strain isolated from a black BE lesion (CML 2985). The enzyme activity of peroxidase (POX), catalase (CAT), superoxide dismutase (SOD), ascorbate peroxidase (APX) and phenylalanine ammonia lyase (PAL) were determined. Activities of POX, APX, and PAL increased in plants inoculated with both strains compared to non-inoculated plants at 12 and 24 hours post inoculation (hpi). CAT activity increased in inoculated plants with black BE strain at 24 hpi and both strains at 48 hpi. The SOD activity only increased in inoculated plants with both strains at 48 hpi. These results show that an elevated antioxidant response was observed when the plants were challenged with both strains of C. coffeicola. Both strains produced lesions of the common type, suggesting that other factors lead to the development of black BE lesion type under field conditions and further investigation is needed.

RESUMO: A cercosporiose, causada pelo fungo Cercospora coffeicola, é uma das principais doenças que afeta o cafeeiro. Uma variação nos sintomas de cercosporiose foi encontrada no campo, levantando suspeitas da ocorrência de uma nova espécie. Considerando que informações sobre a interação cafeeiro-C. coffeicola ainda são limitadas, objetivou-se, neste trabalho, determinar diferenças no metabolismo oxidativo de plantas de cafeeiro, cultivar 'Mundo Novo', inoculadas com isolado proveniente de lesões de cercosporiose do tipo olho pardo (CML 2984) e isolado proveniente de lesões de cercosporiose do tipo negra (CML 2985). Foram determinadas a atividade das enzimas peroxidase (POX), catalase (CAT), superóxido dismutase (SOD), ascorbato peroxidase (APX) e fenilalanina amônia liase (PAL). As atividades das enzimas POX, APX e PAL aumentaram nas plantas inoculadas com ambos os isolados, quando comparadas com as plantas não inoculadas às 12 e 24 horas após inoculação (hai). A atividade da CAT aumentou nas plantas inoculadas com o isolado que causa sintomas de cercosporiose do tipo negra às 24 hai e, para ambos os isolados, às 48 hai. Plantas inoculadas com ambos os isolados demonstraram aumento na atividade da SOD somente às 48 hai. Este estudo mostrou que uma resposta antioxidante elevada foi observada quando as plantas foram inoculadas com os dois isolados de C. coffeicola . Ambos os isolados produziram lesões de cercosporiose do tipo comum, sugerindo que outros fatores que causam lesões de cercosporiose do tipo negra ainda necessitam ser investigados.

Alterations in antioxidant metabolism in coffee leaves infected by Cercospora coffeicola / Alterações no metabolismo antioxidante de folhas de cafeeiro infectadas por Cercospora coffeicola

Brown eye spot (BE) caused by Cercospora coffeicola is the main disease of coffee crop. A variation in symptoms of BE has been reported in the field, raising suspicion of occurrence of new species. However, information about coffee- C. coffeicola interaction is still limited. This research aimed to determine the difference between antioxidant metabolism of coffee plants cultivar Mundo Novo inoculated with a strain isolated from a common BE lesion (CML 2984) and a strain isolated from a black BE lesion (CML 2985). The enzyme activity of peroxidase (POX), catalase (CAT), superoxide dismutase (SOD), ascorbate peroxidase (APX) and phenylalanine ammonia lyase (PAL) were determined. Activities of POX, APX, and PAL increased in plants inoculated with both strains compared to non-inoculated plants at 12 and 24 hours post inoculation (hpi). CAT activity increased in inoculated plants with black BE strain at 24 hpi and both strains at 48 hpi. The SOD activity only increased in inoculated plants with both strains at 48 hpi. These results show that an elevated antioxidant response was observed when the plants were challenged with both strains of C. coffeicola. Both strains produced lesions of the common type, suggesting that other factors lead to the development of black BE lesion type under field conditions and further investigation is needed.(AU)

A cercosporiose, causada pelo fungo Cercospora coffeicola, é uma das principais doenças que afeta o cafeeiro. Uma variação nos sintomas de cercosporiose foi encontrada no campo, levantando suspeitas da ocorrência de uma nova espécie. Considerando que informações sobre a interação cafeeiro-C. coffeicola ainda são limitadas, objetivou-se, neste trabalho, determinar diferenças no metabolismo oxidativo de plantas de cafeeiro, cultivar 'Mundo Novo', inoculadas com isolado proveniente de lesões de cercosporiose do tipo olho pardo (CML 2984) e isolado proveniente de lesões de cercosporiose do tipo negra (CML 2985). Foram determinadas a atividade das enzimas peroxidase (POX), catalase (CAT), superóxido dismutase (SOD), ascorbato peroxidase (APX) e fenilalanina amônia liase (PAL). As atividades das enzimas POX, APX e PAL aumentaram nas plantas inoculadas com ambos os isolados, quando comparadas com as plantas não inoculadas às 12 e 24 horas após inoculação (hai). A atividade da CAT aumentou nas plantas inoculadas com o isolado que causa sintomas de cercosporiose do tipo negra às 24 hai e, para ambos os isolados, às 48 hai. Plantas inoculadas com ambos os isolados demonstraram aumento na atividade da SOD somente às 48 hai. Este estudo mostrou que uma resposta antioxidante elevada foi observada quando as plantas foram inoculadas com os dois isolados de C. coffeicola . Ambos os isolados produziram lesões de cercosporiose do tipo comum, sugerindo que outros fatores que causam lesões de cercosporiose do tipo negra ainda necessitam ser investigados.(AU)

Aplicação exógena de quitosana no sistema antioxidante de jaborandi / Exogenous chitosan application on antioxidant systems of jaborandi

A aplicação de eliciadores em plantas é utilizada em estudos de fisiologia para compreensão dos mecanismos de defesa ao ataque de herbívoros ou infecção por patógenos. Em virtude disso, foi avaliado o efeito do eliciador exógeno quitosana no sistema antioxidante enzimático de jaborandi (Piper mollicomum Kunth). Foram avaliadas as atividades das enzimas ascorbato peroxidase (APX), catalase (CAT) e superóxido dismutase (SOD) e as concentrações de peróxido de hidrogênio (H2O2) e malonaldeído (MDA), ambas análises para verificar a peroxidação lipídica. O delineamento experimental utilizado foi o de blocos casualizados (DBC), constituído de um fatorial (5x2) composto pelos controles sem quitosana (plantas sem pulverização e plantas pulverizadas apenas com o solvente de diluição da quitosana) e concentrações de quitosana (2,5; 5,0 e 10,0 g L-1) em dois estádios de desenvolvimento foliar (em desenvolvimento e completamente expandida). Nas folhas completamente expandidas, o sistema antioxidante foi mais ativo. A CAT teve maior participação no sequestro de radicais livres, induzido pela aplicação da quitosana em ambos os estádios de desenvolvimento foliar. A APX foi induzida somente nas folhas completamente expandidas e na maior concentração de quitosana. O método do MDA foi melhor para evidenciar a diferença nos teores de peróxido de hidrogênio, em função do estresse induzido pela quitosana. De acordo com os resultados obtidos neste ensaio, pode-se sugerir que, nas plantas de jaborandi, as enzimas antioxidativas são requisitadas em resposta ao eliciador em questão, a quitosana, compondo, assim, o mecanismo de defesa dessas plantas.

Elicitors are used in plant physiology studies for comprehension of defense mechanisms against herbivore attach and pathogen infections. For this reason, the exogenous chitosan effect was tested as an elicitor on Jaborandi (Piper mollicomum Kunth). Thus, it was evaluated the elicitor effect in the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) ,ascorbate peroxidase (APX),hydrogen peroxide (H2O2) and malonaldehyde (MDA) concentrations to estimate the lipid peroxidation. The experimental design was in randomized blocks in a factorial 5x2, being 2 controls (plants without pulverization and plants sprayed only with a diluting solvent chitosan) and 3 chitosan concentrations (2.5; 5.0 and 10.0 g L-1) in 2 leaf development stage (in development and fully expanded). At the fully expanded leaves, the antioxidant system presented higher active. The CAT had greater involvement in the kidnapping of free radicals induced by the application of chitosan in both leaf stages of development. The APX was induced only in fully expanded leaves and the highest concentration of chitosan. The MDA method was better to highlight the difference in hydrogen peroxide content as a function of stress induced by chitosan. According to the results of this test, it can be suggested that the plants Jaborandi antioxidant enzymes are required in response to the elicitor in question, chitosan, thus composing the defense mechanism of these plants.

Aplicação exógena de quitosana no sistema antioxidante de jaborandi

Elicitors are used in plant physiology studies for comprehension of defense mechanisms against herbivore attach and pathogen infections. For this reason, the exogenous chitosan effect was tested as an elicitor on Jaborandi (Piper mollicomum Kunth). Thus, it was evaluated the elicitor effect in the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) ,ascorbate peroxidase (APX),hydrogen peroxide (H2O2) and malonaldehyde (MDA) concentrations to estimate the lipid peroxidation. The experimental design was in randomized blocks in a factorial 5x2, being 2 controls (plants without pulverization and plants sprayed only with a diluting solvent chitosan) and 3 chitosan concentrations (2.5; 5.0 and 10.0 g L-1) in 2 leaf development stage (in development and fully expanded). At the fully expanded leaves, the antioxidant system presented higher active. The CAT had greater involvement in the kidnapping of free radicals induced by the application of chitosan in both leaf stages of development. The APX was induced only in fully expanded leaves and the highest concentration of chitosan. The MDA method was better to highlight the difference in hydrogen peroxide content as a function of stress induced by chitosan. According to the results of this test, it can be suggested that the plants Jaborandi antioxidant enzymes are required in response to the elicitor in question, chitosan, thus composing the defense mechanism of these plants.

A aplicação de eliciadores em plantas é utilizada em estudos de fisiologia para compreensão dos mecanismos de defesa ao ataque de herbívoros ou infecção por patógenos. Em virtude disso, foi avaliado o efeito do eliciador exógeno quitosana no sistema antioxidante enzimático de jaborandi (Piper mollicomum Kunth). Foram avaliadas as atividades das enzimas ascorbato peroxidase (APX), catalase (CAT) e superóxido dismutase (SOD) e as concentrações de peróxido de hidrogênio (H2O2) e malonaldeído (MDA), ambas análises para verificar a peroxidação lipídica. O delineamento experimental utilizado foi o de blocos casualizados (DBC), constituído de um fatorial (5x2) composto pelos controles sem quitosana (plantas sem pulverização e plantas pulverizadas apenas com o solvente de diluição da quitosana) e concentrações de quitosana (2,5; 5,0 e 10,0 g L-1) em dois estádios de desenvolvimento foliar (em desenvolvimento e completamente expandida). Nas folhas completamente expandidas, o sistema antioxidante foi mais ativo. A CAT teve maior participação no sequestro de radicais livres, induzido pela aplicação da quitosana em ambos os estádios de desenvolvimento foliar. A APX foi induzida somente nas folhas completamente expandidas e na maior concentração de quitosana. O método do MDA foi melhor para evidenciar a diferença nos teores de peróxido de hidrogênio, em função do estresse induzido pela quitosana. De acordo com os resultados obtidos neste ensaio, pode-se sugerir que, nas plantas de jaborandi, as enzimas antioxidativas são requisitadas em resposta ao eliciador em questão, a quitosana, compondo, assim, o mecanismo de defesa dessas plantas.

Aplicação exógena de quitosana no sistema antioxidante de jaborandi

Elicitors are used in plant physiology studies for comprehension of defense mechanisms against herbivore attach and pathogen infections. For this reason, the exogenous chitosan effect was tested as an elicitor on Jaborandi (Piper mollicomum Kunth). Thus, it was evaluated the elicitor effect in the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) ,ascorbate peroxidase (APX),hydrogen peroxide (H2O2) and malonaldehyde (MDA) concentrations to estimate the lipid peroxidation. The experimental design was in randomized blocks in a factorial 5x2, being 2 controls (plants without pulverization and plants sprayed only with a diluting solvent chitosan) and 3 chitosan concentrations (2.5; 5.0 and 10.0 g L-1) in 2 leaf development stage (in development and fully expanded). At the fully expanded leaves, the antioxidant system presented higher active. The CAT had greater involvement in the kidnapping of free radicals induced by the application of chitosan in both leaf stages of development. The APX was induced only in fully expanded leaves and the highest concentration of chitosan. The MDA method was better to highlight the difference in hydrogen peroxide content as a function of stress induced by chitosan. According to the results of this test, it can be suggested that the plants Jaborandi antioxidant enzymes are required in response to the elicitor in question, chitosan, thus composing the defense mechanism of these plants.

A aplicação de eliciadores em plantas é utilizada em estudos de fisiologia para compreensão dos mecanismos de defesa ao ataque de herbívoros ou infecção por patógenos. Em virtude disso, foi avaliado o efeito do eliciador exógeno quitosana no sistema antioxidante enzimático de jaborandi (Piper mollicomum Kunth). Foram avaliadas as atividades das enzimas ascorbato peroxidase (APX), catalase (CAT) e superóxido dismutase (SOD) e as concentrações de peróxido de hidrogênio (H2O2) e malonaldeído (MDA), ambas análises para verificar a peroxidação lipídica. O delineamento experimental utilizado foi o de blocos casualizados (DBC), constituído de um fatorial (5x2) composto pelos controles sem quitosana (plantas sem pulverização e plantas pulverizadas apenas com o solvente de diluição da quitosana) e concentrações de quitosana (2,5; 5,0 e 10,0 g L-1) em dois estádios de desenvolvimento foliar (em desenvolvimento e completamente expandida). Nas folhas completamente expandidas, o sistema antioxidante foi mais ativo. A CAT teve maior participação no sequestro de radicais livres, induzido pela aplicação da quitosana em ambos os estádios de desenvolvimento foliar. A APX foi induzida somente nas folhas completamente expandidas e na maior concentração de quitosana. O método do MDA foi melhor para evidenciar a diferença nos teores de peróxido de hidrogênio, em função do estresse induzido pela quitosana. De acordo com os resultados obtidos neste ensaio, pode-se sugerir que, nas plantas de jaborandi, as enzimas antioxidativas são requisitadas em resposta ao eliciador em questão, a quitosana, compondo, assim, o mecanismo de defesa dessas plantas.

Exogenous chitosan application on antioxidant systems of jaborandi / Aplicação exógena de quitosana no sistema antioxidante de jaborandi

Elicitors are used in plant physiology studies for comprehension of defense mechanisms against herbivore attach and pathogen infections. For this reason, the exogenous chitosan effect was tested as an elicitor on Jaborandi (Piper mollicomum Kunth). Thus, it was evaluated the elicitor effect in the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) ,ascorbate peroxidase (APX),hydrogen peroxide (H2O2) and malonaldehyde (MDA) concentrations to estimate the lipid peroxidation. The experimental design was in randomized blocks in a factorial 5x2, being 2 controls (plants without pulverization and plants sprayed only with a diluting solvent chitosan) and 3 chitosan concentrations (2.5; 5.0 and 10.0 g L-1) in 2 leaf development stage (in development and fully expanded). At the fully expanded leaves, the antioxidant system presented higher active. The CAT had greater involvement in the kidnapping of free radicals induced by the application of chitosan in both leaf stages of development. The APX was induced only in fully expanded leaves and the highest concentration of chitosan. The MDA method was better to highlight the difference in hydrogen peroxide content as a function of stress induced by chitosan. According to the results of this test, it can be suggested that the plants Jaborandi antioxidant enzymes are required in response to the elicitor in question, chitosan, thus composing the defense mechanism of these plants.(AU)

A aplicação de eliciadores em plantas é utilizada em estudos de fisiologia para compreensão dos mecanismos de defesa ao ataque de herbívoros ou infecção por patógenos. Em virtude disso, foi avaliado o efeito do eliciador exógeno quitosana no sistema antioxidante enzimático de jaborandi (Piper mollicomum Kunth). Foram avaliadas as atividades das enzimas ascorbato peroxidase (APX), catalase (CAT) e superóxido dismutase (SOD) e as concentrações de peróxido de hidrogênio (H2O2) e malonaldeído (MDA), ambas análises para verificar a peroxidação lipídica. O delineamento experimental utilizado foi o de blocos casualizados (DBC), constituído de um fatorial (5x2) composto pelos controles sem quitosana (plantas sem pulverização e plantas pulverizadas apenas com o solvente de diluição da quitosana) e concentrações de quitosana (2,5; 5,0 e 10,0 g L-1) em dois estádios de desenvolvimento foliar (em desenvolvimento e completamente expandida). Nas folhas completamente expandidas, o sistema antioxidante foi mais ativo. A CAT teve maior participação no sequestro de radicais livres, induzido pela aplicação da quitosana em ambos os estádios de desenvolvimento foliar. A APX foi induzida somente nas folhas completamente expandidas e na maior concentração de quitosana. O método do MDA foi melhor para evidenciar a diferença nos teores de peróxido de hidrogênio, em função do estresse induzido pela quitosana. De acordo com os resultados obtidos neste ensaio, pode-se sugerir que, nas plantas de jaborandi, as enzimas antioxidativas são requisitadas em resposta ao eliciador em questão, a quitosana, compondo, assim, o mecanismo de defesa dessas plantas.(AU)

Viability and susceptibility of propagation material from coffee plants to Colletotrichum sp / Viabilidade e suscetibilidade de material propagativo de cafeeiro a Colletotrichum sp

This study aimed to verify the viability of propagation material from coffee plants descended from germplasm susceptible to blister spot disease as well as its susceptibility to Colletotrichum sp. relative to commercial coffee cultivars. In the first experiment, fruits were harvested from plants with and without symptoms of blister spot and sowed in trays containing a commercial sterilized substrate. The percentages of germinated seeds, viable plantlets and seedlings were evaluated. In diseased tissues, pathogens were isolated and identified though a pathogenicity test. In the second experiment, ten commercial cultivars and one cultivar originating from plants with blister spot were inoculated with the pathogens to assess the severity of anthracnose. Significant differences were not observed with respect to seed germination. However, the viability of plantlets and seedlings was reduced in the cultivar originating from plants with blister spot (Genotype Originated from Diseased Plants-GODP). These plants showed characteristic symptoms of blister spot, including necrosis in the leaves and hypocotyls, wilting and death. In the necrotic lesions, we observed characteristic sporulation of Colletotrichum sp. The cultivar most susceptible to anthracnose in cotyledonary leaves was Catuaí Vermelho (GODP), which presented the highest area under the disease progress curve (AUDPC)...(AU)

Objetivou-se neste trabalho verificar a viabilidade de material propagativo de cafeeiro proveniente de germoplasma susceptível a Mancha manteigosa, assim como a sua susceptibilidade a Colletotrichum sp. em comparação a cultivares comerciais de cafeeiro. No primeiro experimento, frutos foram colhidos de plantas com e sem sintomas da mancha manteigosa e a semeadura realizada em bandejas contendo substrato esterilizado. Avaliou-se a porcentagem de sementes germinadas e de plântulas e mudas viáveis. Realizou-se o isolamento, a identificação do patógeno dos tecidos doentes e o teste de patogenicidade. No segundo experimento, inoculou-se o patógeno em dez cultivares de cafeeiro e em uma cultivar originada de plantas com Mancha manteigosa (GOPD) para a avaliação da severidade da antracnose. Não houve diferença quanto à germinação das sementes. Porém, a viabilidade das plântulas e das mudas, foi reduzida nos GOPDs. Estes apresentaram sintomas da mancha manteigosa, necrose nas folhas e nos hipocótilos, murcha e morte. Nas lesões necrosadas observou-se esporulação característica de Colletotrichum spp. A cultivar Catuaí Vermelho (GOPD) foi altamente suscetível à antracnose nas folhas cotiledonares apresentando a maior AACPD em relação aos outros genótipos testados. Conclui-se que a viabilidade de material propagativo de cafeeiro proveniente de sementes de plantas com Mancha manteigosa...(AU)