Comprehensive Review of Fungi on Coffee

Polyherbal nanoformulation: a potent antifungal agent on fungal pathogens of Coffea arabica

Agriculture is the backbone of all countries which dictates the major economy of the country. The management of pathogens is critical in the field of agriculture. Many species of pathogenic fungi infect a broad range of hosts including cash crops and agricultural crops. Coffee is one of the most important commercial crop in the economy of many countries in the world. Coffea arabica is infected by several fungal species and results in decrease in the quality and quantity of coffee berries. Infection of fungi in plants not only kills the plants and fruit yield but also affect human being through toxin intoxication. Chemical fungicides are the primary choice for the control of plant pathogenic fungi. However, these chemicals pollute the environment, disturb the normal flora, fauna and aquatic environment. The intake of fungicides through inhalation or ingestion results in serious health consequences including immunological, endocrinal, neurological, gynaecological, and carcinogenic effects. Hence, it is a challenge to find a novel alternative green solution to control both pathogenic fungi and to detoxify the fungal toxins. Green nanotechnology can be adopted to develop eco-friendly nanoformulation to control fungal pathogens. In this study, fungal pathogens were isolated from infected coffee plants and identified through sequencing. The novelty of the study stands on uniqueness of Polyherbal nanoformulation which was synthesized by using Triphala. Antifungal studies were carried out by using a developed Polyherbal nanoformulation. From the results, fungal pathogens were identified as Cladorrhinum flexuosum, Rigidoporus vinctus, Mucor circinelloides, Mucor lusitanicus, and Nigrospora oryzae. On treating these fungal pathogens with PHNF, the radial growth of fungal strains was effectively controlled even at lower concentration of 3.125 µg/ml. The specific contribution of PHNF is 'synergism' which plays a significant role in controlling the growth of tested fungal pathogens. On further exploration of PHNF in field conditions will help to optimize the dosage for the commercial development of nano based fungicide for the benefit of farmers as well as a solution to global problem. In addition, these PHNF can be formulated to nanosprays and nanomaterials to control the fungal growth during post-harvest condition.

Unveiling fungal diversity associated with coffee trees in China using a polyphasic approach and a global review of coffee saprobic fungi

Arabica coffee (Coffeaarabica) is the most cultured and popular coffee bean in today's world. Yunnan Province is well known as China's largest arabica coffee cultivation region. Fungi represent an important group of microorganisms associated with coffee, profoundly influencing its yield and quality. In this study, twelve fungal collections growing on dead and decaying twigs of coffee were collected and isolated to systematically document microfungi associated with coffee plants in Yunnan Province. Ten novel species, each representing a unique family within Pleosporales, were identified and introduced, based on comprehensive morphological analyses and multigene phylogenetic studies. The ten new species belong to the families Bambusicolaceae, Didymellaceae, Didymosphaeriaceae, Longiostiolaceae, Lophiostomataceae, Massarinaceae, Neomassariaceae, Occultibambusaceae, Roussoellaceae and Thyridariaceae with each family containing one new species. Macro- and micro-characteristics, descriptions and phylogenetic trees indicating the placement of the new taxa are provided. In addition, pairwise homoplasy index (PHI) test results and morphological comparisons between the new species and closely-related taxa are given. This study also establishes a comprehensive global inventory of saprobic fungi associated with coffee, which is intended to help researchers and professionals worldwide with practical information. This research enhances the understanding of coffee-associated fungal diversity in China and underscores the importance of introducing new saprobic fungal taxa related to coffee.

Occurrence of ochratoxins in coffee and risk assessment of ochratoxin a in a Costa Rican urban population

Costa Rica is a coffee producer and consumer country, but this product is prone to ochratoxin contamination; therefore, this study aims evaluates the human health risk associated with ochratoxin exposure among coffee consumers in the Costa Rica. Ochratoxin A (OTA) is a nephrotoxic compound classified as a Group 2B carcinogen, produced by the fungi Aspergillus section Circumdati, Aspergillus section Nigri and Penicillium spp.  The presence of OTA and ochratoxin B (OTB) in Costa Rican coffee products (n = 175) was determined by HPLC with fluorescence detection. OTA was detected in 58.2% of the green coffee beans (1.01 ± 0.85 ng g -1), in 36.8% of the pure roasted coffee (2.59 ± 4.41 ng g -1), in 23.1% of the sugar-added roasted coffee (1.59 ± 0.33 ng g-1) and 75% of the instant coffee samples (0.69 ± 0.58 ng g-1). The contamination with OTB was 45.5% (1.28 ± 0.83 ng g -1), 31.6% (1.60 ± 2.04 ng g -1), 30.8% (1.42 ± 0.86 ng g -1), and 41.7% (2.64 ± 2.07 ng g -1), respectively. The dietary exposure to OTA of the Costa Rican population was assessed by a probabilistic approach. The mean estimated daily intake (EDI) of OTA from coffee was: 0.184 (90% IC: 0.179-0.189) ng kg-1 bw day-1 for the total population (0.189 [90% IC: 0.184-0.194] ng kg-1 bw day-1 for males and 0.181 [90% IC: 0.176-0.186] ng kg-1 bw day-1 for females).  The EDIs were lower than the tolerable human intake benchmarks for OTA set by international food safety authorities (even though more than 80% of OTA is extracted during coffee preparation). The results evidence a low risk (related to ochratoxin) for coffee consumers in Costa Rica.

Morphological and molecular identification of two new Marasmiellus species (Omphalotaceae, Agaricales) from Thailand

Marasmiellus (Omphalotaceae, Agaricales) specimens collected in Thailand were investigated based on morphological characteristics and molecular phylogenetic analyses. In the present study, two species are introduced as new to science, namely Marasmiellusthailandicus and M.minutisporus. Phylogenetic analyses were carried out based on the internal transcribed spacer (nrITS) and nuclear ribosomal RNA large subunit (nrLSU) regions, and the results revealed that the two new taxa are distinct species within Marasmiellus. Another specimen was identified as M.scandens and is reported for the first time with morphology and molecular data from Thailand. Descriptions, illustrations, and phylogenetic results are provided. In addition, M.diaphanus and M.colocasiae are proposed as new combinations of Collybiopsisdiaphana and Paramarasmiuscolocasiae, respectively, based on the phylogenetic evidence.

Survey of potential fungal antagonists of Coffee Leaf Rust (Hemileia vastatrix) on Coffea arabica in Hawai'i, USA

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'ū, Hāmākua, 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.

Thermal Contaminants in Coffee Induced by Roasting: A Review

Roasting is responsible for imparting the main characteristics to coffee, but the high temperatures used in the process can lead to the formation of several potentially toxic substances. Among them, polycyclic aromatic hydrocarbons, acrylamide, furan and its derivative compounds, α-dicarbonyls and advanced glycation end products, 4-methylimidazole, and chloropropanols stand out. The objective of this review is to present a current and comprehensive overview of the chemical contaminants formed during coffee roasting, including a discussion of mitigation strategies reported in the literature to decrease the concentration of these toxicants. Although the formation of the contaminants occurs during the roasting step, knowledge of the coffee production chain as a whole is important to understand the main variables that will impact their concentrations in the different coffee products. The precursors and routes of formation are generally different for each contaminant, and the formed concentrations can be quite high for some substances. In addition, the study highlights several mitigation strategies related to decreasing the concentration of precursors, modifying process conditions and eliminating/degrading the formed contaminant. Many of these strategies show promising results, but there are still challenges to be overcome, since little information is available about advantages and disadvantages in relation to aspects such as costs, potential for application on an industrial scale and impacts on sensory properties.

The natural occurrence, toxicity mechanisms and management strategies of Fumonisin B1：A review

Fumonisin B1 (FB1) contaminates various crops, causing huge losses to agriculture and livestock worldwide. This review summarizes the occurrence regularity, toxicity, toxic mechanisms and management strategies of FB1. Specifically, FB1 contamination is particularly serious in developing countries, humid and hot regions. FB1 exposure can produce different toxic effects on the nervous system, respiratory system, digestive system and reproductive system. Furthermore, FB1 can also cause systemic immunotoxicity. The mechanism of toxic effects of FB1 is to interfere with the normal pathway of sphingolipid de novo biosynthesis by acting as a competitive inhibitor of ceramide synthase. Meanwhile, the toxic products of sphingolipid metabolic disorders can cause oxidative stress and apoptosis. FB1 also often causes feed contamination by mixing with other mycotoxins, and then exerts combined toxicity. For detection, lateral flow dipstick technology and enzyme linked immunosorbent assay are widely used in the detection of FB1 in commercial feeds, while mainstream detection methods such as high performance liquid chromatography and liquid chromatography-mass spectrometry are widely used in the laboratory theoretical study of FB1. For purification means of FB1, some natural plant extracts (such as Zingiber officinale and Litsea Cubeba essential oil) and their active compounds have been proved to inhibit the toxic effects of FB1 and protect livestock due to their antifungal and antioxidant effects. Natural plant extract has the advantages of high efficiency, low cost and no contamination residue. This review can provide information for comprehensive understanding of FB1, and provide reference for formulating reasonable treatment and management strategies in livestock production.

Three new species of Nigrograna (Dothideomycetes, Pleosporales) associated with Arabica coffee from Yunnan Province, China

Coffee is one of the most important cash crops in Yunnan Province, China. Yunnan is ranked as the biggest producer of high-quality coffee in China. During surveys of microfungi from coffee plantations in Yunnan, six fungal strains that resemble Nigrogranaceae were collected. Multi-gene analyses of a combined SSU-LSU-ITS-rpb2-tef1-α sequence data matrix were used to infer the phylogenetic position of the new species in Nigrograna while morphological characteristics were used to deduce the taxonomic position of the new species. Six fungal strains isolated from decaying branches of Coffeaarabica represent three new saprobic species in Nigrograna. The three new species, N.asexualis, N.coffeae, and N.puerensis, are described with full (macro and micro characteristics) descriptions, illustrations, and a phylogenetic tree that shows the phylogenetic position of new taxa.

Description of Four Novel Species in Pleosporales Associated with Coffee in Yunnan, China

In Yunnan Province, the coffee-growing regions are mainly distributed in Pu’er and Xishuangbanna. During the surveys of microfungi associated with coffee in Yunnan Province, seven taxa were isolated from coffee samples. Based on molecular phylogenetic analyses of combined ITS, LSU, SSU, rpb2, and tef1-α sequence data and morphological characteristics, four new species viz. Deniquelata yunnanensis, Paraconiothyrium yunnanensis, Pseudocoleophoma puerensis, and Pse. yunnanensis, and three new records viz. Austropleospora keteleeriae, Montagnula thailandica, and Xenocamarosporium acaciae in Pleosporales are introduced. In addition, Paracamarosporium fungicola was transferred back to Paraconiothyrium based on taxonomy and DNA sequences. Full descriptions, illustrations, and phylogenetic trees to show the placement of new and known taxa are provided. In addition, the morphological comparisons of new taxa with closely related taxa are given.

Antifungal activity of poly(ε-caprolactone) nanoparticles incorporated with Eucalyptus essential oils against Hemileia vastatrix

Coffee (Coffea L.) is one of the main crops produced globally. Its contamination by the fungus Hemileia vastatrix Berkeley and Broome has been economically detrimental for producers. The objective of this work was to extract and characterize the essential oils from Eucalyptus citriodora Hook, Eucalyptus camaldulensis Dehn and Eucalyptus grandis Hill ex Maiden, produce and characterize nanoparticles containing these essential oils, and evaluate the in vivo and in vitro antifungal activity of free and nanoencapsulated essential oils. The principal constituents of the essential oil from E. citriodora was citronellal , that from E. grandis was α-pinene , and that from E. camaldulensis was 1,8-cineol. The in vitro antifungal activity against the fungus H. vastatrix was 100% at a concentration of 1000 μl l^-1 for all the oils and nanoparticles containing these natural products. The sizes of the nanoparticles produced with the essential oils from E. citriodora, E. camaldulensis and E. grandis were 402.13 nm, 275.33 nm and 328.5 nm, respectively, with surface charges of -11.8 mV, -9.24 mV and -6.76 mV, respectively. Fourier transform infrared analyses proved that the encapsulation of essential oils occurred in the polymeric matrix of poly(ε-caprolactone). The incorporation of essential oils into biodegradable poly(ε-caprolactone) nanoparticles increased their efficiency as biofungicides in the fight against coffee rust, decreasing the severity of the disease by up to 90.75% after treatment with the nanoparticles conaining the essential oil from E. grandis.