Search Results (16)

Given the challenges of climate change, effective adaptation strategies for crops like coffee are crucial. This study evaluated twelve 1-aminocyclopropane-1-carboxylate deaminase-producing bacterial strains selectively isolated from the rhizosphere of Coffea arabica L. cv. Costa Rica 95 in a plantation located in Veracruz, Mexico, focusing on their potential to enhance drought resistance. The strains, representing seven genera from the Gamma-proteobacteria and Bacteroidota groups, were characterized for growth-promoting traits, including ACC deaminase activity, indole-3-acetic acid (IAA) synthesis, phosphates solubilization, siderophore production, and nitrogen fixation. Strains of the genus Pantoea exhibited higher ACC deaminase activity, phosphate solubilization, and IAA synthesis, while others, such as Sphingobacterium and Chryseobacterium, showed limited plant growth-promoting traits. A pot experiment was conducted with coffee plants subjected to either full irrigation (soil with 85% volumetric water content) or drought (soil with 55% volumetric water content) conditions, along with inoculation with the isolated strains. Plants inoculated with Pantoea sp. RCa62 demonstrated improved growth metrics and physiological traits under drought, including higher leaf area, relative water content (RWC), biomass, and root development compared to uninoculated controls. Similar results were observed with Serratia sp. RCa28 and Pantoea sp. RCa31 under full irrigation conditions. Pantoea sp. RCa62 exhibited superior root development under stress, contributing to overall plant development. Proline accumulation was significantly higher in drought-stressed, non-inoculated plants compared to those inoculated with Pantoea sp. RCa62. This research highlights the potential of Pantoea sp. RCa62 to enhance coffee plant resilience to drought and underscores the need for field application and further validation of these bioinoculants in sustainable agricultural practices. Full article

Peru is one of the leading countries that produce and export specialty coffees, favorably positioned in the international markets for its physical and organoleptic cup qualities. In recent years, yellow coffee rust caused by the phytopathogenic fungus Hemileia vastatrix stands out as one of the main phytosanitary diseases that affect coffee culture yields. Many studies have demonstrated bacteria antagonistic activity against a number of phytopathogen fungi. In this context, the aim of this work was to select and characterize phyllospheric bacteria isolated from Coffea arabica with antagonistic features against coffee rust to obtain biocontrollers. For that purpose, a total of 82 phyllospheric bacteria were isolated from two coffee leaf rust-susceptible varieties, typica and caturra roja, and one tolerant variety, catimor. Of all the isolates, 15% were endophytic and 85% were epiphytes. Among all the isolates, 14 were capable of inhibiting the mycelial radial growth of Mycena citricolor, and Colletotrichum sp. 16S rRNA gene sequence-based analysis showed that 9 isolates were related to Achromobacter insuavis, 2 were related to Luteibacter anthropi and 1 was related to Rodococcus ceridiohylli, Achromobacter marplatensis and Pseudomonas parafulva. A total of 7 representative bacteria of each group were selected based on their antagonistic activity and tested in germination inhibition assays of coffee rust uredinospores. The CRRFLT7 and TRFLT8 isolates showed a high inhibition percentage of urediniospores germination (81% and 82%, respectively), similar to that obtained with the chemical control (91%). An experimental field assay showed a good performance of both strains against rust damage too, making them a promising alternative for coffee leaf rust biocontrol. Full article

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. Full article

The microbial composition and physical-chemical characteristics were studied during the coffee fermentation of three Coffea arabica L. varieties, Var. Tabi, Var. Castillo General^® and Var. Colombia. Mucilage and washed coffee seeds samples were collected at different stages of fermentation. Mucilage microbiology characterization and metataxonomic analysis were performed using 16S rDNA sequencing to determine bacterial diversity and ITS sequencing for fungal diversity. Additionally, the microorganisms were isolated into pure cultures. The molecular diversity analyses showed similarities in microorganisms present during the fermentation of Var. Castillo General and Var. Colombia, which are genetically closely related; mixed-acid bacteria (Enterobacteriaceae, Tatumella sp.) and lactic acid bacteria (Leuconostoc sp., Weissella sp. and Lactobacillaceae) were common and predominant, while in Var. Tabi, acetic acid bacteria (Gluconobacter sp. and Acetobacter sp.) and Leuconostoc sp. were predominant. At the end of the fermentation period, the fungi Saccharomycodaceae, Pichia and Wickerhamomyces were found in Var. Castillo General and Var. Colombia, while in Var. Tabi, Saccharomycodaceae, Pichia and Candida were recorded. Sensory analyses of the coffee beverages were carried out (SCA methodology) for all samples. Var. Tabi had the highest SCA score, between 82.7 and 83.2, while for Var. Colombia, the score ranged between 82.1 and 82.5. These three coffee varieties showed potential for the production of specialty coffees influenced by spontaneous fermentation processes that depend on microbial consortia rather than a single microorganism. Full article

Over the centuries, human society has evolved based on the ability to select and use more adapted species for food supply, which means making plant species tastier and more productive in particular environmental conditions. However, nowadays, this scenario is highly threatened by climate change, especially by the changes in temperature and greenhouse gasses that directly affect photosynthesis, which highlights the need for strategic studies aiming at crop breeding and guaranteeing food security. This is especially worrying for crops with complex phenology, genomes with low variability, and the ones that support a large production chain, such as Coffea sp. L. In this context, recent advances shed some light on the genome function and transcriptional control, revealing small RNAs (sRNAs) that are responsible for environmental cues and could provide variability through gene expression regulation. Basically, sRNAs are responsive to environmental changes and act on the transcriptional and post-transcriptional gene silencing pathways that regulate gene expression and, consequently, biological processes. Here, we first discuss the predicted impact of climate changes on coffee plants and coffee chain production and then the role of sRNAs in response to environmental changes, especially temperature, in different species, together with their potential as tools for genetic improvement. Very few studies in coffee explored the relationship between sRNAs and environmental cues; thus, this review contributes to understanding coffee development in the face of climate change and towards new strategies of crop breeding. Full article

The use of bacterial inoculants is an attractive alternative that could reduce the consumption of chemical fertilizers in crops. In the production system of quality coffee seedlings, it is essential to achieve an adequate balance of nutrients that allows for healthy plants that are resistant to subsequent handling. The objective of this work was to evaluate the effect of Rhizobium sp. inoculation on the growth, nutrition and quality of coffee seedlings cultivated with different doses of phosphoric fertilization. Inoculation tests were carried out under nursery conditions using Coffea arabica L. cv. “Isla 5–15” and Coffea canephora Pierre ex Froehner cv. “Robusta” seeds inoculated with the Rhizobium sp. Rpr2 strain. Sixty days after sowing, the hypocotyldonal graft was performed, and the resulting plants were also treated with the bacterial inoculant. Plants were then planted in substrate with different doses of phosphorus (P): 25, 50, 75 and 100%. At seven months of cultivation, variables of growth (plant height, stem diameter, number of leaf pairs, main root length, root volume, dry mass of the aerial part, root and total), phosphoric nutrition (leaf and root P contents) and posture quality index were evaluated. The inoculation stimulated the aerial part (37%), root growth (34%), the quality index of the grafted postures (30%), and phosphorus absorption (42%) and allowed a decrease from 25 to 75% of the mineral fertilizer. For the first time in Cuba, the benefits of rhizobial inoculation on the nutrition and quality of coffee seedlings were demonstrated. The inoculation of grafted coffee seedlings with Rhizobium sp. Rpr2 through the inoculation method proposed in this study can be recommended as a new easy, cost-effective and efficient inoculation approach to obtain additional benefits for coffee growth, improving the absorption of nutritive elements and the quality characteristics of the coffee seedlings. Full article

Several insect pests are related to the cultivation of conilon coffee, Coffea canephora (Rubiaceae), including (Hemiptera: Coccomorpha). Coccoids damage plants by sucking their sap, producing honeydew, and transmitting viruses. Parasitoids and predators are natural enemies that regulate the insect population and can be used in mealybug biological control. This study aimed to survey scale insects and natural enemies associated with C. canephora in the city of Jaboticabal, São Paulo State, Brazil. Two species of mealybugs from the family Coccidae and three from the family Pseudococcidae were collected in different plant structures. Natural enemies collected comprised hymenopteran parasitoids from the families Aphelinidae, Eulophidae, Encyrtidae, and Perilampidae; predator beetles of the family Coccinellidae; dipterans from the family Cecidomyiidae; and thrips of the family Aeolothripidae. This is the first report of the mealybug species Coccus brasiliensis, Pseudococcus longispinus, and Pseudococcus cryptus; of the parasitoids Coccophagus rusti, Aprostocetus sp., Aenasius advena, Aenasius fusciventris, Aenasius pseudococci, and Perilampus sp.; and of the predators Cycloneda conjugata, Pseudoazya nana, Diadiplosis coccidivora, Diadiplosis sp., and Franklinothrips vespiformis, associated with C. canephora. Knowledge of mealybug species and their respective natural enemies will contribute to biological control strategies in planning the integrated management of mealybugs associated with conilon coffee. Full article

In this study, twelve terrestrial hysteriaceous saprobic fungi growing on different pieces of dead wood were collected from Yunnan Province, China. All hysteriaceous strains isolated in this study tallied with the general characteristics associated with Rhytidhysteron. Detailed morphological characteristics and combined multigene phylogeny of LSU, ITS, SSU, and TEF showed that the twelve hysteriaceous fungi strains represent four distinct new species, and seven new host or geographical records of Rhytidhysteron. Based on morphological and phylogenetic evidence, the four new species (Rhytidhysteron bannaense sp. nov., R. coffeae sp. nov., R. mengziense sp. nov., and R. yunnanense sp. nov.) expand the number of species of Rhytidhysteron from thirty-three to thirty-seven, while seven new geographical records expand the records of Rhytidhysteron in China from six to thirteen. In addition, 10 new Rhytidhysteron host records are reported for the first time, thus expanding the known hosts for Rhytidhysteron from 52 to 62. Full descriptions, images of the morphology, and phylogenetic analyses to show the position of the Rhytidhysteron taxa are provided. In addition, the present study summarizes the main morphological characteristics, host associations, and locations of this genus. Full article

Roasted coffee silver skin is a coffee by-product, the uses of which are currently limited, e.g., as fertilizer, for energy production, or animal feed. Due to a low content of fat and carbohydrates combined with a high content of fiber, polyphenols and proteins, roasted silver skin is a valuable possible food ingredient. Potential applications include partial flour replacement in bakery products, as antioxidant and providing protein or fiber sources in sports or functional foods. As no relevant consumption of isolated silver skin occurred before 1997 in the European Union (EU), it was classified as a novel food in need of premarketing approval. Novel food applications must meet legal requirements for compositional and toxicological information. This review presents information on silver skin composition and toxicological studies. Several in vitro studies and subchronic in vivo studies are available with negative results, not suggesting a need for further studies on carcinogenic effects, reproduction, or chronic toxicity. All available studies so far concluded that no toxic effects of silver skin were found or are to be expected. For a novel food application in the EU, further in vitro studies on mutagenic potential may be needed to close a formal data gap. Full article

Species of Paramyrothecium that are reported as plant pathogens and cause leaf spot or leaf blight have been reported on many commercial crops worldwide. In 2019, during a survey of fungi causing leaf spots on plants in Chiang Mai and Mae Hong Son provinces, northern Thailand, 16 isolates from 14 host species across nine plant families were collected. A new species Paramyrothecium vignicola sp. nov. was identified based on morphology and concatenated (ITS, cmdA, rpb2, and tub2) phylogeny. Further, P. breviseta and P. foliicola represented novel geographic records to Thailand, while P. eichhorniae represented a novel host record (Psophocarpus sp., Centrosema sp., Aristolochia sp.). These species were confirmed to be the causal agents of the leaf spot disease through pathogenicity assay. Furthermore, cross pathogenicity tests on Coffea arabica L., Commelina benghalensis L., Glycine max (L.) Merr., and Dieffenbachia seguine (Jacq.) Schott revealed multiple host ranges for these pathogens. Further research is required into the host–pathogen relationship of Paramyrothecium species that cause leaf spot and their management. Biotic and abiotic stresses caused by climate change may affect plant health and disease susceptibility. Hence, proper identification and monitoring of fungal communities in the environment are important to understand emerging diseases and for implementation of disease management strategies. Full article

Coffee leaf rust is caused by Hemileia vastatrix Berk. and Broome and is the most important coffee disease in all regions where coffee is cultivated. Here, we sought to sequence the transcriptome of H. vastatrix race XXXIII to obtain a database for use as a reference in studies of the interaction between the fungus and coffee. In addition, we aimed to identify differentially expressed genes that have the potential to act as effector proteins during the interaction. Sequencing of cDNA libraries from uredospores and from compatible and incompatible interactions at different key time points generated about 162 million trimmed reads. We identified 3523 differentially expressed genes. The results suggested that the fungal transcriptome is dynamically altered over the course of infection and that the interaction with a susceptible plant upregulates a larger set of fungal genes than the interaction with a resistant plant. Co-expression network analysis allowed us to identify candidate genes with the same expression pattern as that of other effectors of H. vastatrix. Quantitative PCR analysis identified seven transcripts that may be effectors involved in the coffee–H. vastatrix interaction. This information provides a basis for obtaining new insights into the molecular mechanisms of infection in this pathosystem. Understanding gene expression during the infection process may contribute to elucidating the molecular mechanisms leading to the breakdown of resistance by new physiological races of the fungus. Full article

Coffea arabica is one of the most important crops worldwide. In vitro culture is an alternative for achieving Coffea regeneration, propagation, conservation, genetic improvement, and genome editing. The aim of this work was to identify proteins involved in auxin homeostasis by isobaric tandem mass tag (TMT) and the synchronous precursor selection (SPS)-based MS3 technology on the Orbitrap Fusion™ Tribrid mass spectrometer™ in three types of biological materials corresponding to C. arabica: plantlet leaves, calli, and suspension cultures. Proteins included in the β-oxidation of indole butyric acid and in the signaling, transport, and conjugation of indole-3-acetic acid were identified, such as the indole butyric response (IBR), the auxin binding protein (ABP), the ATP-binding cassette transporters (ABC), the Gretchen-Hagen 3 proteins (GH3), and the indole-3-acetic-leucine-resistant proteins (ILR). A more significant accumulation of proteins involved in auxin homeostasis was found in the suspension cultures vs. the plantlet, followed by callus vs. plantlet and suspension culture vs. callus, suggesting important roles of these proteins in the cell differentiation process. Full article

The study of microbes associated with the coffee tree has been gaining strength in recent years. In this work, we compared the leaf mycobiome of the traditional crop Coffea arabica with wild species Coffea racemosa and Coffea stenophylla using ITS sequencing for qualitative information and real-time PCR for quantitative information, seeking to relate the mycobiomes with the content of caffeine and chlorogenic acid in leaves. Dothideomycetes, Wallemiomycetes, and Tremellomycetes are the dominant classes of fungi. The core leaf mycobiome among the three Coffea species is formed by Hannaella, Cladosporium, Cryptococcus, Erythrobasidium, and Alternaria. A network analysis showed that Phoma, an important C. arabica pathogen, is negatively related to six fungal species present in C. racemosa and C. stenophylla and absent in C. arabica. Finally, C. arabica have more than 35 times the concentration of caffeine and 2.5 times the concentration of chlorogenic acid than C. stenophylla and C. racemosa. The relationship between caffeine/chlorogenic acid content, the leaf mycobiome, and genotype pathogen resistance is discussed. Full article

Coffee is a crop of great economic importance in many countries. The organic coffee crop stands out from other production systems by aiming to eliminate the use of synthetic fertilizers and pesticides. One of the most important limitations in the organic system is the management of diseases, especially coffee rust, which is considered the main disease of this crop. Coffee rust causes a production slump of up to 50%, significantly affecting the profitability of coffee growers. This work aims to review the integrated rust management in organic coffee crop in different producing countries. Regarding the disease management strategies, this review addresses the use of rust-resistant cultivars, cultural management, biological control, use of plant extracts, and chemical rust control by cupric fungicides. Considering the importance of the organic system, the increase in world coffee consumption, and the potential market for this kind of coffee, this review may help researchers and producers looking for alternative strategies to control rust in an organic coffee cultivation system. Full article

Despite the negative impacts of increased ultraviolet radiation intensity on plants, these organisms continue to grow and produce under the increased environmental UV levels. We hypothesized that ambient UV intensity can generate acclimations in plant growth, leaf morphology, and photochemical functioning in modern genotypes of Coffea arabica and C. canephora. Coffee plants were cultivated for ca. six months in a mini greenhouse under either near ambient (UVam) or reduced (UVre) ultraviolet regimes. At the plant scale, C. canephora was substantially more impacted by UVam when compared to C. arabica, investing more carbon in all juvenile plant components than under UVre. When subjected to UVam, both species showed anatomic adjustments at the leaf scale, such as increases in stomatal density in C. canephora, at the abaxial and adaxial cuticles in both species, and abaxial epidermal thickening in C. arabica, although without apparent impact on the thickness of palisade and spongy parenchyma. Surprisingly, C. arabica showed more efficient energy dissipation mechanism under UVam than C. canephora. UVam promoted elevated protective carotenoid content and a greater use of energy through photochemistry in both species, as reflected in the photochemical quenching increases. This was associated with an altered chlorophyll a/b ratio (significantly only in C. arabica) that likely promoted a greater capability to light energy capture. Therefore, UV levels promoted different modifications between the two Coffea sp. regarding plant biomass production and leaf morphology, including a few photochemical differences between species, suggesting that modifications at plant and leaf scale acted as an acclimation response to actual UV intensity. Full article