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1.
Proc Natl Acad Sci U S A ; 118(27)2021 07 06.
Artigo em Inglês | MEDLINE | ID: mdl-34183411

RESUMO

In this perspective, we draw on recent scientific research on the coffee leaf rust (CLR) epidemic that severely impacted several countries across Latin America and the Caribbean over the last decade, to explore how the socioeconomic impacts from COVID-19 could lead to the reemergence of another rust epidemic. We describe how past CLR outbreaks have been linked to reduced crop care and investment in coffee farms, as evidenced in the years following the 2008 global financial crisis. We discuss relationships between CLR incidence, farmer-scale agricultural practices, and economic signals transferred through global and local effects. We contextualize how current COVID-19 impacts on labor, unemployment, stay-at-home orders, and international border policies could affect farmer investments in coffee plants and in turn create conditions favorable for future shocks. We conclude by arguing that COVID-19's socioeconomic disruptions are likely to drive the coffee industry into another severe production crisis. While this argument illustrates the vulnerabilities that come from a globalized coffee system, it also highlights the necessity of ensuring the well-being of all. By increasing investments in coffee institutions and paying smallholders more, we can create a fairer and healthier system that is more resilient to future social-ecological shocks.


Assuntos
COVID-19/epidemiologia , Café , Epidemias , Basidiomycota/fisiologia , COVID-19/economia , Café/economia , Café/microbiologia , Meio Ambiente , Epidemias/economia , Fazendas/economia , Fazendas/tendências , Indústrias/economia , Indústrias/tendências , Doenças das Plantas/economia , Doenças das Plantas/microbiologia , SARS-CoV-2 , Fatores Socioeconômicos
2.
Molecules ; 29(4)2024 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-38398508

RESUMO

Tryptophan synthase (TRPS) is a complex enzyme responsible for tryptophan biosynthesis. It occurs in bacteria, plants, and fungi as an αßßα heterotetramer. Although encoded by independent genes in bacteria and plants, in fungi, TRPS is generated by a single gene that concurrently expresses the α and ß entities, which are linked by an elongated peculiar segment. We conducted 1 µs all-atom molecular dynamics simulations on Hemileia vastatrix TRPS to address two questions: (i) the role of the linker segment and (ii) the comparative mode of action. Since there is not an experimental structure, we started our simulations with homology modeling. Based on the results, it seems that TRPS makes use of an already-existing tunnel that can spontaneously move the indole moiety from the α catalytic pocket to the ß one. Such behavior was completely disrupted in the simulation without the linker. In light of these results and the αß dimer's low stability, the full-working TRPS single genes might be the result of a particular evolution. Considering the significant losses that Hemileia vastatrix causes to coffee plantations, our next course of action will be to use the TRPS to look for substances that can block tryptophan production and therefore control the disease.


Assuntos
Basidiomycota , Simulação de Dinâmica Molecular , Triptofano Sintase , Triptofano Sintase/química , Triptofano Sintase/genética , Triptofano Sintase/metabolismo , Triptofano , Fungos/metabolismo
3.
Plant Dis ; 107(2): 247-261, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-35698251

RESUMO

Although integrating trees into agricultural systems (i.e., agroforestry systems) provides many valuable ecosystem services, the trees can also interact with plant diseases. We demonstrate that a detailed understanding of how plant diseases interact with trees in agroforestry systems is necessary to identify key tree canopy characteristics, leaf traits, spatial arrangements, and management options that can help control plant diseases at different spatial scales. We focus our analysis on how trees affect coffee leaf rust, a major disease affecting one of the world's most significant crop commodities. We show that trees can both promote and discourage the development of coffee leaf rust at the plot scale via microclimate modifications in the understory. Based on our understanding of the role of tree characteristics in shaping the microclimate, we identify several canopy characteristics and leaf traits that can help manage coffee leaf rust at the plot scale: namely, thin canopies with high openness, short base height, horizontal branching, and small, dentate leaves. In contrast, at the edge of coffee farms, having large trees with high canopy volume and small, thick, waxy leaves is more useful to reduce throughflow wind speeds and intercept the airborne dispersal of urediniospores, an important consideration to control disease at the landscape scale. Seasonal pruning can help shape trees into the desired form, and trees can be spatially arranged to optimize desired effects. This case study demonstrates the added value of combining process-based epidemiology studies with functional trait ecology to improve disease management in agroforestry systems.


Assuntos
Basidiomycota , Coffea , Árvores , Ecossistema , Agricultura
4.
Int J Mol Sci ; 24(22)2023 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-38003355

RESUMO

The coffee industry faces coffee leaf rust caused by Hemileia vastratix, which is considered the most devastating disease of the crop, as it reduces the photosynthetic rate and limits productivity. The use of plant resistance inducers, such as chitosan, is an alternative for the control of the disease by inducing the synthesis of phytoalexins, as well as the activation of resistance genes. Previously, the effect of chitosan from different sources and physicochemical properties was studied; however, its mechanisms of action have not been fully elucidated. In this work, the ability of food-grade high-density chitosan (0.01% and 0.05%) to control the infection caused by the pathogen was evaluated. Subsequently, the effect of high-density chitosan (0.05%) on the induction of pathogenesis-related gene expression (GLUC, POX, PAL, NPR1, and CAT), the enzymatic activity of pathogenesis-related proteins (GLUC, POX, SOD, PPO, and APX), and phytoalexin production were evaluated. The results showed that 0.05% chitosan increased the activity and gene expression of ß-1,3 glucanases and induced a differentiated response in enzymes related to the antioxidant system of plants. In addition, a correlation was observed between the activities of polyphenol oxidase and the production of phytoalexin, which allowed an effective defense response in coffee plants.


Assuntos
Basidiomycota , Quitosana , Coffea , Coffea/genética , Quitosana/farmacologia , Fitoalexinas , Basidiomycota/genética , Doenças das Plantas/genética
5.
J Sci Food Agric ; 101(7): 2836-2845, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33135174

RESUMO

BACKGROUND: The occurrence of diseases can alter coffee (Coffea arabica L.) metabolism, causing changes in the composition of coffee beans and beverage quality. However, little is known about which aspects of coffee quality are actually altered by rust (Hemileia vastatrix Berk et Br.) and by its main control methods. The effect of chemical and genetic methods for the control of coffee rust on the quality of coffee beans and beverage was investigated. RESULTS: Both genetic and chemical control reduce the damage caused by the disease in the composition of coffee beans. Genotypes with resistant ancestry, even with resistance breakdown, respond better to chemical control. The combination of genetic and chemical control favors an increase in the sugar content in the beans. CONCLUSIONS: Despite the fact that both genetic and chemical control are effective in reducing disease damage regarding the chemical composition of beans, the quality potential of Timor Hybrid genotypes associated with the cancellation of rust expression through the joint action of genetic and chemical control favors the composition of beans and, consequently, the quantitative assessment of sensory attributes, adding value to the final product. © 2020 Society of Chemical Industry.


Assuntos
Basidiomycota/fisiologia , Coffea/microbiologia , Doenças das Plantas/microbiologia , Sementes/química , Basidiomycota/genética , Coffea/química , Café/química , Genótipo , Humanos , Sementes/microbiologia , Paladar
6.
Phytopathology ; 110(2): 418-427, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31502519

RESUMO

Crop health management systems can be designed according to practices that help to reduce crop losses by restricting pathogen development and promoting host plant growth. A good understanding of pathogen and host dynamics, which are interdependent, is therefore needed. In this article, we used a holistic approach to explain the behavior of coffee leaf rust (CLR), a major coffee disease. We monitored coffee plant and CLR dynamics simultaneously in plots under different disease management and agroforestry systems. Diseased leaves were also collected to characterize inoculum stock and rust life stages (latent rust area, area with uredospores, necrosis due to rust) through picture analysis. We used structural equation modeling to obtain an overview of CLR pathosystem functioning on a plant scale. This overview integrates processes such as disease dilution by host leaf renewal, direct and indirect effects of fruit load on CLR development, antagonistic effects of shading depending on rust life stages, the tonic effect of copper-based fungicides on leaf retention, and effects on rust life stages depending on fungicide types. From our results, we also deduced that the inoculum stock could be calculated in unsprayed plots from the rust area with uredospores, with uredospores at 58 × 103 cm-2, on average.


Assuntos
Agricultura , Basidiomycota , Coffea , Modelos Biológicos , Doenças das Plantas , Basidiomycota/fisiologia , Coffea/microbiologia , Fungicidas Industriais , Doenças das Plantas/microbiologia , Folhas de Planta/microbiologia
7.
Plant Dis ; 104(4): 1013-1018, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32065564

RESUMO

The El Niño Southern Oscillation (ENSO) is an oceanic-atmospheric phenomenon influencing worldwide weather and climate. Its occurrence is determined by the sea surface temperature (SST) anomaly of the 3.4 Niño region in the Pacific Ocean (5°N-5°S, 120°-170°W). El Niño (EN), Neutral (NT), and La Niña (LN) are the three possible phases of ENSO, respectively, for warm, normal, and cold SST anomaly. As in other regions around the world, weather in Brazil is influenced by ENSO phases. The country is the major coffee producer in the world, and production is strongly influenced by weather conditions, which affect plant yield, harvest quality, and interactions with pests and diseases. Coffee leaf rust (CLR), caused by the fungus Hemileia vastatrix, is a major cause of coffee yield and quality losses in Brazil, and requires fungicide spray applications every season. Because CLR is highly influenced by weather conditions, it is possible to use weather variables to simulate its progress during the cropping cycle. Therefore, the aims of this study were to estimate CLR infection rate based on a validated empirical model, which has daily minimum air temperature and relative humidity as inputs, and to assess the extent of ENSO influence on the annual risk of this disease at 45 sites in Brazil. Cumulative infection rates (CIR) were estimated daily from October to June of each growing season and location, based on the prevailing ENSO phase. Differences between the extreme phases (EN-LN) were assessed by the Two-One-Sided-Tests (TOST) method. Analysis of data from eight sites, located mainly in Paraná State, provided evidence of CIR differences between EN and LN phases (G1). Evidence of no difference of CIR between EN and LN was found in 18 sites (G2), whereas 19 sites showed no evidence of differences (G3) due to relatively large variation of CIR within the same ENSO phase. The G1 sites are located mostly in Southern Brazil, where ENSO exerts a well-defined influence on rainfall regime. In contrast, the G2 sites are mainly in Minas Gerais State, which is characterized as a transition region for ENSO influence on rainfall. The G3 sites are located between the northern region of Minas Gerais State and southern region of Bahia State, which is characterized by a subhumid climate that is usually very dry during winter, and where rainfall can vary up to 300% from one year to another, influencing relative humidity and resulting in a high CIR variability. Therefore, ENSO had a well-defined influence on CIR only in Paraná State, a region with minor importance for coffee production in Brazil. No ENSO influence was found in more northerly zones where the majority of Brazilian coffee is produced. This is the first evidence of ENSO-linked regional impact on the risk of coffee rust.


Assuntos
Café , El Niño Oscilação Sul , Brasil , Estações do Ano , Tempo (Meteorologia)
8.
Int J Biometeorol ; 62(10): 1847-1860, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30051219

RESUMO

Brazil is the major coffee producer in the world, with 2 million hectares cropped, with 75% of this area with Coffea arabica and 25% with Coffea canephora. Coffee leaf rust (CLR) is one of the main diseases that cause yield losses by reducing healthy leaf area. As CLR is highly influenced by weather conditions, this study aimed to determine the best linearization model to estimate the CLR apparent infection rate, to correlate CLR infection rates with weather variables, and to develop and assess the performance of weather-based infection rate models to be used as a disease warning system. The CLR epidemic was analyzed for 88 site-seasons, while progress curves were assessed by linear, monomolecular, logistic, Gompertz, and exponential linearization models for apparent infection rate determination. Correlations between CLR infection rates and weather variables were conducted at different periods. From these correlations, multiple linear regressions were developed to estimate CLR infection rates, using the most weather-correlated variables. The Gompertz growth model had the best fit with CLR progress curves. Minimum temperature and relative humidity were the weather variables most correlated to infection rate and, therefore, chosen to compose a CLR forecast system. Among the models developed, the one for the condition of high coffee yield at a narrow row spacing was the best, with only 9.4% of false negative occurrences for all the months assessed.


Assuntos
Café , Doenças das Plantas , Tempo (Meteorologia) , Basidiomycota , Brasil , Coffea
9.
New Phytol ; 213(3): 1315-1329, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27918080

RESUMO

A number of genes that confer resistance to coffee leaf rust (SH 1-SH 9) have been identified within the genus Coffea, but despite many years of research on this pathosystem, the complementary avirulence genes of Hemileia vastatrix have not been reported. After identification of H. vastatrix effector candidate genes (HvECs) expressed at different stages of its lifecycle, we established an assay to characterize HvEC proteins by delivering them into coffee cells via the type-three secretion system (T3SS) of Pseudomonas syringae pv. garcae (Psgc). Employing a calmodulin-dependent adenylate cyclase assay, we demonstrate that Psgc recognizes a heterologous P. syringae T3SS secretion signal which enables us to translocate HvECs into the cytoplasm of coffee cells. Using this Psgc-adapted effector detector vector (EDV) system, we found that HvEC-016 suppresses the growth of Psgc on coffee genotypes with the SH 1 resistance gene. Suppression of bacterial blight symptoms in SH 1 plants was associated with reduced bacterial multiplication. By contrast, HvEC-016 enhanced bacterial multiplication in SH 1-lacking plants. Our findings suggest that HvEC-016 may be recognized by the plant immune system in a SH 1-dependent manner. Thus, our experimental approach is an effective tool for the characterization of effector/avirulence proteins of this important pathogen.


Assuntos
Basidiomycota/fisiologia , Coffea/genética , Coffea/microbiologia , Resistência à Doença/genética , Proteínas Fúngicas/metabolismo , Genes de Plantas , Doenças das Plantas/microbiologia , Pseudomonas syringae/patogenicidade , Adenilil Ciclases/metabolismo , Sequência de Aminoácidos , Sistemas de Secreção Bacterianos , Basidiomycota/genética , Éxons/genética , Proteínas Fúngicas/química , Regulação da Expressão Gênica de Plantas , Genes Fúngicos , Genótipo , Íntrons/genética , Pseudomonas syringae/crescimento & desenvolvimento , Alinhamento de Sequência
10.
J Sci Food Agric ; 94(3): 529-36, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23801071

RESUMO

BACKGROUND: Plants have developed an efficient system of recognition that induces a complex network of signalling molecules such as salicylic acid (SA), jasmonic acid (JA) and abscisic acid (ABA) in case of a pathogenic infection. The use of specific and sensitive methods is mandatory for the analysis of compounds in these complex samples. RESULTS: In this study a liquid chromatography/electrospray ionisation tandem mass spectrometry method was developed and validated for the simultaneous quantification of SA, JA and ABA in Coffea arabica (L.) leaves in order to understand the role of these phytohormones in the signalling network involved in the coffee defence response against Hemileia vastatrix. The results showed that the method was specific, linear (r ≥ 0.99) in the range 0.125-1.00 µg mL⁻¹ for JA and ABA and 0.125-5.00 µg mL⁻¹ for SA, and precise (relative standard deviation ≤11%), and the limit of detection (0.010 µg g⁻¹ fresh weight) was adequate for quantifying these phytohormones in this type of matrix. CONCLUSION: In comparison with healthy leaves, those infected with H. vastatrix (resistance reaction) displayed an increase in SA level 24 h after inoculation, suggesting the involvement of an SA-dependent pathway in coffee resistance.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Coffea/química , Resistência à Doença , Doenças das Plantas/microbiologia , Reguladores de Crescimento de Plantas/análise , Folhas de Planta/química , Espectrometria de Massas por Ionização por Electrospray/métodos , Ácido Abscísico/análise , Coffea/microbiologia , Ciclopentanos/análise , Fungos , Oxilipinas/análise , Folhas de Planta/microbiologia , Reprodutibilidade dos Testes , Ácido Salicílico/análise , Transdução de Sinais , Espectrometria de Massas em Tandem/métodos
11.
Braz J Microbiol ; 55(3): 2839-2844, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38743246

RESUMO

Hemileia vastatrix, causal agent of coffee leaf rust (CLR), is an aggressive pathogen of coffee plants worldwide. Conventional fungicides play a major role in the suppression of this disease, but a recent shift toward eco-friendly farming practices has occurred and additional novel, effective, and sustainable strategies for CLR control are needed. Naturally occurring fungal antagonists could be well-positioned to meet this demand, but these fungi need to be isolated and tested for efficacy to identify organisms with potential. In this study, a survey of fungi associated with CLR lesions in four districts of Hawai'i Island, HI, USA (Kona, Ka'u, Hamakua, and Hilo) was conducted. Coffee leaves infected with CLR were collected from 22 locations and over 600 lesions were plated on ½ APDA and CTC 4T media. DNA was extracted from purified isolates and the internal transcribed spacer region (ITS) was sequenced and analyzed by BLASTn. In total, 194 isolates comprising 50 taxa were recovered. Several of the genera are known antagonists of CLR or other plant pathogens, including Simplicillium, Akanthomyces, Cladosporium, Fusarium, and Clonostachys. The wide diversity of fungi associated with CLR lesions provide a wealth of possibilities for identifying potential CLR antagonists that could serve as a valuable tool for coffee farmers as part of an integrated pest management plan.


Assuntos
Coffea , Doenças das Plantas , Folhas de Planta , Coffea/microbiologia , Havaí , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle , Folhas de Planta/microbiologia , Fungos/classificação , Fungos/isolamento & purificação , Fungos/genética , Fungos/efeitos dos fármacos , Basidiomycota/isolamento & purificação , Basidiomycota/genética , Basidiomycota/classificação , Antibiose
12.
Plants (Basel) ; 13(6)2024 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-38592839

RESUMO

Coffee has immense value as a worldwide-appreciated commodity. However, its production faces the effects of climate change and the spread of severe diseases such as coffee leaf rust (CLR). The exploration of fungal endophytes associated with Coffea sp. has already found the existence of nearly 600 fungal species, but their role in the plants remains practically unknown. We have researched the diversity of leaf fungal endophytes in two Coffea arabica varieties: one susceptible and one resistant to CLR. Then, we conducted cross-infection essays with four common endophyte species (three Colletotrichum sp. and Xylaria sp. 1) and Hemileia vastatrix (CLR) in leaf discs, to investigate the interaction of the endophytes on CLR colonisation success and severity of infection. Two Colletotrichum sp., when inoculated 72 h before H. vastatrix, prevented the colonisation of the leaf disc by the latter. Moreover, the presence of endophytes prior to the arrival of H. vastatrix ameliorated the severity of CLR. Our work highlights both the importance of characterising the hidden biodiversity of endophytes and investigating their potential roles in the plant-endophyte interaction.

13.
Plants (Basel) ; 12(20)2023 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-37895983

RESUMO

Coffee leaf rust (CLR) is caused by the biotrophic fungus Hemileia vastatrix Berk. & Br., a disease of economic importance, reducing coffee yield up to 60%. Currently, CLR epidemics have negatively impacted food security. Therefore, the objective of the present research study is to show a current framework of this disease and its effects on diverse areas, as well as the biological systems used for its control, mode of action, and effectiveness. The use of essential plant oils and antagonistic microorganisms to H. vastatrix are highlighted. Terpenes, terpenoids, and aromatic compounds are the main constituents of these oils, which alter the cell wall and membrane composition and modify the basic cell functions. Beneficial microorganisms inhibit urediniospore germination and reduce disease incidence and severity. The antagonistic microorganisms and essential oils of some aromatic plants have great potential in agriculture. These biological systems may have more than one mechanism of action, which reduces the possibility of the emergence of resistant strains of H. vastatrix.

14.
Microbiol Resour Announc ; 12(11): e0044423, 2023 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-37791781

RESUMO

Coffee leaf rust, caused by the fungus Hemileia vastatrix (Basidiomycota; Pucciniomycota), is a devastating disease spread worldwide. To improve the available genomes, we use PacBio HiFi sequencing enhanced by Dovetail Omni-C chromatin conformation capture to assemble a highly contiguous 747.98 Mb genome of an isolate collected from Coffea arabica.

15.
Data Brief ; 43: 108433, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35859787

RESUMO

Here we describe the proteome of the fungus Hemileia vastatrix by label free mass spectrometry (LC-MS/MS). H. vastatrix is the causal agent of coffee rust disease, causing great economic losses in this crop. The objective of our work was to identify H. vastatrix proteins potentially involved in host colonization and infection, by exploring the shotgun proteomics approach. A total of 742 proteins were identified and are associated with several crucial molecular functions, biological processes, and cellular components. The proteins identified contribute to a better understanding of the metabolism of the fungus and may help identify target proteins for the development of specific drugs in order to control coffee rust disease. All data can be accessed at the Centre for Computational Mass Spectrometry - MassIVE MSV000087665 -https://massive.ucsd.edu/ProteoSAFe/dataset.jsp?task=cc71ad75f767451abe72dd1ce0019387.

16.
Mol Biotechnol ; 64(3): 263-277, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34595725

RESUMO

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.


Assuntos
Café/crescimento & desenvolvimento , Resistência à Doença , Proteínas de Plantas/genética , Café/classificação , Café/genética , Café/microbiologia , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Lignina/biossíntese , Fenóis/metabolismo , Folhas de Planta/classificação , Folhas de Planta/genética , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/microbiologia
17.
Front Plant Sci ; 13: 872877, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35449887

RESUMO

This research focused on the incidence and population genetics of coffee leaf rust (CLR) fungus, Hemileia vastatrix, to estimate the possible original source(s) and subsequent migration pathways of wind-borne and human-aided spores in three main coffee production regions (Northwest, Central Highlands, and Southeast) in Vietnam. In southern Vietnam (Central Highlands and Southeast), Coffea canephora covers the majority area, while Catimor lines of C. arabica accounts for 95% of the coffee plantations in northwestern Vietnam. Field surveys conducted at eighty-five plantations, show coffee leaf samples infected by the rust fungus across forty-one plantations. Catimor varieties exhibited high levels of susceptibility with severe rust symptoms, while robusta varieties had varying degrees of susceptibility. We analyzed 863-869 base pairs of internal transcribed spacer (ITS) region from 83 samples (41 sequences from Vietnam, 2 from Thailand, and the remaining 40 from American countries); and fifty-two haplotypes consisting of 123 polymorphic sites were detected. Although the analysis of molecular variance (AMOVA) indicates significant genetic differentiation in the H. vastatrix populations in Vietnam, there was no clear genetic structure with respect to the three geographic areas surveyed. Based on the haplotype network, NeighborNet analysis, and geographical distribution patterns of the haplotypes, five haplotypes were identified as early established, from which most other haplotypes in Vietnam were derived. The early established haplotypes were found in the highest frequency in Northwest Vietnam. This finding corresponds to the earliest record of CLR in Vietnam. The phylogenetic network analysis also illustrated that H. vastatrix had expanded from the northwest to southern Vietnam. Pairwise genetic distance analysis and the geophylogenetic tree also suggests that CLR was first established in the Northwest. In addition, some scattered individuals on the principal coordinate analysis (PCoA) diagram and several separated haplotypes in the phylogenetic networks indicated that other branches of CLR in Vietnam were initiated in the Central Highlands. Hemileia vastatrix from these branches have been spreading in southern Vietnam.

18.
Heliyon ; 8(12): e11892, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36506396

RESUMO

Ethiopian Arabica coffee is produced in different agroforestry systems which differ in forest management intensity. In forest coffee systems (FC), coffee shrubs grow naturally in the understory of Afromontane forests with little human intervention, whereas in semi-forest coffee systems (SFC) thinning of the canopy and removal of the understory is applied. Coffee leaf rust (CLR) disease is a growing concern for coffee agroforestry, but to what extent infection pressure is affected by management intensity is poorly known. Here we assessed CLR infection through time across FC and SFC systems in SW-Ethiopia. CLR infection was significantly higher for SFC, with a gradual reduction of this difference during the beginning of dry season (November) through main rainy season of (July). Our findings also demonstrated that CLR infections were significantly lower in the FC system as compared to SFC system in both years 2015/16 and 2020/21. The higher CLR infection was partly explained by lower crown cover and higher human impact. We expect that reduced wind speed and droplet penetration under closed canopies and reduced human-facilitated spore dispersal are the dominating mechanisms behind lower CLR infection in FC systems, yet lower coffee density in FC may also play a role. Overall, our results indicate that although higher management intensity still generally results in higher total yields per hectare, proportionally larger losses due to CLR infection can be expected. Therefore, introducing more coffee genetic diversity, screening resistant coffee varieties and increasing canopy cover in the SFC will mitigate the CLR disease pressure and guarantee the sustainability of higher yields of the system in the future. Also, lower yields in the FC will be rewarded through providing price premiums so that farmers instantly get a higher price for their lower yield, guaranteeing livelihoods.

19.
Plants (Basel) ; 11(20)2022 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-36297767

RESUMO

Hemileia vastatrix (HV) is the pathogen responsible for the coffee leaf rust (CLR) disease that has spread globally. CLR causes losses of up to a billion dollars annually and affects all types of crops regardless of their production regime (organic or inorganic). Additionally, smallholders produce approximately 80% of coffee in developing countries. The condition causes losses of up to a billion dollars annually. It affects all types of crops regardless of their production regime (organic or inorganic). Approximately 80% of coffee is produced by smallholders in developing countries. Until the 90s, shaded-production systems and native varieties were encouraged; however, the rapid spread of CLR has forced farmers to migrate towards inorganic schemes, mainly due to a lack of knowledge about natural alternatives to pesticides that can be implemented to control HV. Therefore, the purpose of this article is to compile the currently existing options, emphasizing two key factors that guarantee efficient rust control: selective fungicidal activity against HV and the nutrition of coffee crops. Thus, by comprehending how these natural compounds (such as plant, bacteria, fungi, animals, or algae metabolites) impact coffee rust proliferation. Furthermore, since a various range of biochar effects contributes to the control of foliar fungal pathogens through modification of root exudates, soil properties, and nutrient availability, which influence the growth of antagonist microorganisms, we present a review of the pathogen-suppressive effects of biochar, and new control strategies suitable for organic schemes can be developed.

20.
Pak J Biol Sci ; 24(5): 588-598, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34486334

RESUMO

<b>Background and Objective:</b> Coffee leaf rust disease caused by <i>Hemileia vastatrix</i> resulted in high yield loss and difficult to control. Several chemical fungicides have been used to control this disease. However, the effectiveness of chemical control is low, so it is necessary to find other methods such as biological control. <i>Lecanicillium</i> spp. is well-known as mycoparasite on <i>H. vastatrix</i> uredospores but the study in Indonesia is still limited. This study aimed to collect and investigated the genetic variability of <i>Lecanicillium</i> spp. at various coffee plantations in Indonesia. <b>Materials and Methods:</b> Samples of <i>Lecanicillium </i>spp. were collected from 20 districts in 7 provinces throughout Indonesia. Morphology of colony and conidia were identified by visual examination and by viewed under the light microscope. Genetic variability was conducted using Rep-PCR and clustered with UPGMA. <b>Results:</b> Morphological observation in this study revealed all isolates collected from uredospores of <i>H. vastatrix</i> were similar with <i>Lecanicillium </i>spp. Genetic variability analysis clustered the 80 isolates into eight clusters with their specific characters. <b>Conclusion:</b> Morphological identification in this study showed that 80 isolates of mycoparasite on <i>H. vastatrix</i> belong to <i>Lecanicillium</i> spp. Further study using the molecular technique is needed to identity the species of <i>Lecanicillium</i>.


Assuntos
Basidiomycota/patogenicidade , Café/efeitos dos fármacos , Hypocreales/isolamento & purificação , Extratos Vegetais/farmacologia , Basidiomycota/metabolismo , Hypocreales/metabolismo , Indonésia , Extratos Vegetais/uso terapêutico
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