Figs 3-10 - uploaded by Antonio Trapero-Casas
Content may be subject to copyright.
Pseudocercospora cladosporioides (epitype). Fig. 3. Fascicle of conidiophores on leaf surface. Fig. 4. Secondary mycelium with conidiophore and conidiogenous scars. Fig. 5-10. Medium brown, subcylindrical conidia in vivo. Bars=10 mm.
Source publication
Cercospora leaf spot of olives is a serious defoliating disease attributed to Pseudocercospora cladosporioides. Although the disease is well distributed throughout olive growing regions of the world, its epidemiology and population structure remains unknown. The aim of this study was to establish the genetic variability of Spanish isolates of P. cl...
Citations
... The causal agent of CLS is the fungus Pseudocercospora cladosporioides, which is characterized by slow growth in culture media and little or no production of conidia (Pappas, 1993;Ávila et al., 2004, 2005, 2020Nigro and Ferrara, 2011). Conidia of the fungus are produced in dark brown stromatic conidiomata, which arise in clusters through the host stomata or directly through the epidermis on the underside of infected leaves (Ávila et al., 2004). ...
Cercospora Leaf Spot (CLS) of olive is an important fungal disease in Uruguay, causing severe early defoliation. Fungal isolates were obtained from olive leaves with typical CLS symptoms from Uruguayan orchards. The isolates were identified based on phenotypic characteristics and DNA sequence analyses. Infection processes under field conditions were characterized. Phylogenetic analyses confirmed that Pseudocercospora cladosporioides is the causal agent of CLS in Uruguay. Three colony morphologies
were observed for isolates growing on potato dextrose agar. Mean conidium length ranged from 65.7 to 101.8 μm, and widths from 4.3 to 5.0 μm. Mean optimum growth temperature was 21.5°C (range 19.2 to 24.8°C). Under field conditions, initial CLS symptoms on leaves were observed 5 months after inoculation of cv. Arbequina plants, confirming the disease’s lengthy incubation period. This study shows that CLS as one of the most prevalent and destructive olive diseases in Uruguay, and emphasizes the importance of further research to develop efficient management of this disease.
... Cercosporoid fungi are dematiaceous hyphomycetes with conidiophores formed singly or in groups, arranged in sporodochia or in synnemata, with integrated, terminal or intercalary conidiogenous cells Ávila et al. 2005;Braun et al. 2013). Most of the cercosporoid species were previously assigned to a single genus, Cercospora, which was later split into several smaller genera mainly by Deighton (1967Deighton ( , 1973Deighton ( , 1974Deighton ( , 1976Deighton ( , 1979, Braun (1993) and Crous and Braun (2003). ...
Cercosporoid fungi (Mycosphaerellaceae, Mycosphaerellales, Ascomycota) are one of the largest and most diverse groups of hyphomycetes causing a wide range of diseases of economically important plants as well as of plants in the wild. Although more than 6000 species are known for this group, the documentation of this fungal group is far from complete. Especially in the tropics, the diversity of cercosporoid fungi is poorly known. The present study aims to identify and characterise cercosporoid fungi collected on host plants belonging to Fabaceae in Benin, West Africa. Information on their morphology, host species and DNA sequence data (18S rDNA, 28S rDNA, ITS and tef1 ) is provided. DNA sequence data were obtained by a simple and non-culture-based method for DNA isolation which has been applied for cercosporoid fungi for the first time in the context of the present study. Among the loci used for the phylogenetic analysis, tef1 provided the best resolution together with the multigene dataset. Species delimitation in many cases, however, was only possible by combining molecular sequence data with morphological characteristics. Based on forty specimens recently collected in Benin, 18 species are presented with morphological descriptions, illustrations and sequence data. Among these, six species in the genus Cercospora and two species in Pseudocercospora are proposed as species new to science. The newly described species are Cercospora (C.) beninensis on Crotalaria macrocalyx , C. parakouensis on Desmodium tortuosum , C. rhynchophora on Vigna unguiculata , C. vignae - subterraneae on Vigna subterranea , C. tentaculifera on Vigna unguiculata , C. zorniicola on Zornia glochidiata , Pseudocercospora sennicola on Senna occidentalis and Pseudocercospora tabei on Vigna unguiculata . Eight species of cercosporoid fungi are reported for Benin for the first time, three of them, namely C. cf. canscorina, C. cf. fagopyri and C. phaseoli-lunati are new for West Africa. The presence of two species of cercosporoid fungi on Fabaceae previously reported from Benin, namely Nothopassalora personata and Passalora arachidicola , is confirmed.
... Cercosporin (CP), one of naturally occurring perylenequinonoid pigments (PQPs) with a characterized 3,10-dihydroxy-4,9-perylenequinone chromophore core structure (Fig. 1a), was first isolated in the mycelium of Cercospora kikuchii in 1957 and then was widely found in many pathogenic fungus Cercospora [1][2][3], which is a causal agent of leaf spot diseases (LSD) in a wide range of crops [4], including soybean [5], maize [6], and olive [7]. ...
Background
Owing to the excellent properties of photosensitization, cercosporin, one of naturally occurring perylenequinonoid pigments, has been widely used in photodynamic therapy, or as an antimicrobial agent and an organophotocatalyst. However, because of low efficiency of total chemical synthesis and low yield of current microbial fermentation, the limited production restricts its broad applications. Thus, the strategies to improve the production of cercosporin were highly desired. Besides traditional optimization methods, here we screened leaf-spot-disease-related endophytic bacteria to co-culture with our previous identified Cercospora sp. JNU001 to increase cercosporin production.
Results
Bacillus velezensis B04 and Lysinibacillus sp. B15 isolated from leaves with leaf spot diseases were found to facilitate cercosporin secretion into the broth and then enhance the production of cercosporin. After 4 days of co-culture, Bacillus velezensis B04 allowed to increase the production of cercosporin from 128.2 mg/L to 984.4 mg/L, which was 7.68-fold of the previously reported one. Lysinibacillus sp. B15 could also enhance the production of cercosporin with a yield of 626.3 mg/L, which was 4.89-fold higher than the starting condition. More importantly, we found that bacteria B04 and B15 employed two different mechanisms to improve the production of cercosporin, in which B04 facilitated cercosporin secretion into the broth by loosening and damaging the hyphae surface of Cercospora sp. JNU001 while B15 could adsorb cercosporin to improve its secretion.
Conclusions
We here established a novel and effective co-culture method to improve the production of cercosporin by increasing its secretion ability from Cercospora sp. JNU001, allowing to develop more potential applications of cercosporin.
... These fungi are known from diverse habitats, and play a large variety of ecological roles. Some of these fungi are pathogens of important crop plants such as banana, citrus, and olive (Á vila et al. 2005;Chang et al. 2016;Aguilera-Cogley et al. 2017). Molecular methods have substantially advanced the problematic taxonomy of genera and species in the Mycosphaerellaceae Videira et al. 2017). ...
During studies to investigate the health of mangrove trees in South Africa, high numbers of Avicennia marina were found with leaf galls caused by unidentified adults and larvae of midges (Cecidomyiidae). Fungal fruiting structures were commonly observed on the abaxial areas of the galls. To determine the identity of the fungi associated with the gall midges, phylogenetic analyses using multigene sequence data were used. The nuclear large subunit (LSU), internal transcribed spacer (ITS), and a portion of the actin gene region (ACT), were amplified and analyzed. The results revealed that the fungal fruiting structures represent a new taxon in the Mycosphaerellaceae described here as Zasmidium mangrovei sp. nov. This is the first report of a species in the Mycosphaerellaceae associated with cecidomyiid leaf galls on A. marina.
... These fungi are known from diverse habitats, and play a large variety of ecological roles. Some of these fungi are pathogens of important crop plants such as banana, citrus, and olive (Á vila et al. 2005;Chang et al. 2016;Aguilera-Cogley et al. 2017). Molecular methods have substantially advanced the problematic taxonomy of genera and species in the Mycosphaerellaceae Videira et al. 2017). ...
During studies to investigate the health of mangrove trees in South Africa, high numbers of Avicennia marina were found with leaf galls caused by unidentified adults and larvae of midges (Cecidomyi-idae). Fungal fruiting structures were commonly observed on the abaxial areas of the galls. To determine the identity of the fungi associated with the gall midges, phylogenetic analyses using multi-gene sequence data were used. The nuclear large subunit (LSU), internal transcribed spacer (ITS), and a portion of the actin gene region (ACT), were amplified and analyzed. The results revealed that the fungal fruiting structures represent a new taxon in the Mycosphaerellaceae described here as Zasmidium mangrovei sp. nov. This is the first report of a species in the Mycosphaerellaceae associated with cecido-myiid leaf galls on A. marina.
... Cercosporin, one of naturally occurring perylenequinonoid pigments (PQPs) with a characterized 3,10dihydroxy-4,9-perylenequinone chromophore core structure (Fig. 1A), was rst isolated in the mycelium of Cercospora kikuchii in 1957 and then was widely found in many pathogenic fungus Cercospora [1-3], which is a causal agent of leaf spot diseases in a wide range of crops [4], including agriculturally important crops such as soybean [5], maize [6], and olive [7]. Owing to its excellent properties of photosensitization, it is widely investigated in the aspects of photophysics, photochemistry and photobiology [8][9][10][11][12][13], and has been used in photodynamic therapy and photophysical diagnosis, or as antimicrobial agents [14][15][16]. ...
Background: Owing to the excellent properties of photosensitization, cercosporin, one of naturally occurring perylenequinonoid pigments, has been widely used in photodynamic therapy, or as an antimicrobial agent and an organophotocatalyst. However, because of low efficiency of total chemical synthesis and low yield of current microbial fermentation, the limited production restricts its broad applications. Thus, the strategies to improve the production of cercosporin were highly desired. Besides traditional optimization methods, here we screened leaf-spot-disease-related endophytic bacteria to co-culture with our previous identified Cercospora sp. JNU001 to increase cercosporin production.
Results: Bacillus velezensis B04 and Lysinibacillus sp. B15 isolated from leaves with leaf spot diseases were found to facilitate cercosporin secretion into the broth and then enhance the production of cercosporin. After 4 days of co-culture, Bacillus velezensis B04 allowed to increase the production of cercosporin from 128.2 mg/L to 984.4 mg/L, which was 7.68-fold of the previously reported one. Lysinibacillus sp. B15 could also enhance the production of cercosporin with a yield of 626.3 mg/L, which was 4.89-fold higher than the starting condition. More importantly, we found that bacteria B04 and B15 employed two different mechanisms to improve the production of cercosporin, in which B04 facilitated cercosporin secretion into the broth by loosening and damaging the hyphae surface of Cercospora sp. JNU001 while B15 could absorb cercosporin to improve its secretion.
Conclusions: We here established a novel and effective co-culture method to improve the production of cercosporin by increasing its secretion ability from Cercospora sp. JNU001, allowing to develop more potential applications of cercosporin.
... The merging of overlapping paired-end reads and further quality filtering was performed using Usearch version 8.0.1623 (Edgar, 2010). Filtering based on sequence size was then applied with fastq-mcf from ea-utils package (Aronesty, 2011). The micca version 1.7.0 software pipeline (Albanese et al., 2015) was performed i) to load the datasets into a single FASTQ file, ii) to discard sequences with an expected error rate greater than 1 %, iii) to assign similar sequences (threshold 97 %) to Operational Taxonomic Units (OTUs) and remove chimeric sequences, and iv) to assign taxonomy to each sequence with a reference database for fungi (UNITE database version 8.0, (Nilsson et al., 2018). ...
A wide array of fungal endophytes is known to inhabit plant tissues and were recently recognized as essential for plant health. A better description of the scarcely known endophyte microbiota in olive tree phyllosphere is the first step for elucidating the microbial interactions that lead to olive disease establishment. In this work, the fungal endophytic community of the phyllosphere of different olive tree cultivars (Cobrançosa, Galega vulgar, Madural, Picual, Verdeal Transmontana) is revealed by using a metabarcoding strategy targeting ITS1 barcode. A total of 460 OTUs were obtained, increasing the broad view of fungal endophytes inhabiting the olive tree phyllosphere, in particular yeast endophytes. New endophytes were persistently found in all cultivar tissues. Different olive tree cultivars depicted distinct endophyte communities. Olive cultivars exhibited dissimilar amounts of fungi with distinct ecological functions, which could explain at least in part their differential susceptibility/tolerance to olive diseases.
... Cercospora leaf spot of olive (CLSO) has been described as one of the most relevant diseases of this crop worldwide [1,[3][4][5] . Typical symptoms of CLSO are grey spots and early leaf fall, leading a less shoot growth, a poor fruit production, decreased flower bud formation in the following years, and a delay in fruit ripening [5][6][7][8]. ...
... Typical symptoms of CLSO are grey spots and early leaf fall, leading a less shoot growth, a poor fruit production, decreased flower bud formation in the following years, and a delay in fruit ripening [5][6][7][8]. Light-green to yellow spots, with may become necrotic, appear on the upper side surface of the leaf, while on the under-side surface, leaden-grey areas also occur with the presence of characteristic lead-black olivaceous asexual fruiting structures [1,[3][4][5]. CLSO symptoms on fruit vary depending on the fruit ripening stage, from brown, sunken, more or less ...
... 3 Risk categories to the infection of aerial olive diseases according to the climatic history of the location (AEMET, 2011) and the particular edaphic and climatic conditions of the experimental field (topography, orientation and presence of rivers and streams nearby). 4 Within these orchards, different experimental trials were selected depending on the cultivar (El Realengo) or the farming system (Cortijo de Guadiana). ...
: Cercospora leaf spot of olive (CLSO), caused by Pseudocercospora cladosporioides, is one of the most important foliar diseases of olives worldwide. This study aimed to evaluate the effect of a wide range of fungicides on mycelial growth and conidial germination of P. cladosporioides in vitro, and to evaluate the effect of several fungicides, application timings and management strategies (conservative and risky) to control CLSO under field conditions. Of the studied fungicides, strobilurin compounds and benomyl were the most effective active ingredients, followed by folpet, captan and maneb, in inhibiting mycelial growth and conidial germination. The pyraclostrobin + boscalid treatment was effective under field conditions, even without the application of supplementary copper. Treatments conducted in October or March were more effective than those conducted in May. Management strategies based on the author’s experience reduced copper applications up to 32.0% and 50.0% (conservative and risky strategy, respectively) in comparison to the reduction with the traditional strategy, without increasing CLSO incidence. This work provides useful information about effective formulations against CLSO and a reduction in unnecessary fungicide applications in an effort to implement IPM in olive orchards under Mediterranean conditions.
... Além disso, condições de alta umidade (< 70%), com a presença de água livre e temperaturas entre 17 e 25C, como ocorreu na região, são fatores que contribuem para o aparecimento de doenças fúngicas, entre elas a antracnose causada por Colletotrichum spp, que interfere diretamente na qualidade do azeite (MORAL et al., 2012), o olho de pavão causado por Fusicladium oleagineum (synonym: Spilocaea oleaginea ) (ROUBAL, et al. 2013) e o emplumado, causado pelo fungo Pseudocercospora cladosporioides (DOMINGUES et al., 2016). As doenças olho de pavão e emplumado, muitas vezes ocorrem de forma associada e ambas provocam queda acentuada das folhas, afetam os frutos e assim como a antracnose, interferem na produtividade (ÁVILA et al., 2005). Contudo, a predominância do tempo seco até a fase de colheita dessa cultura, amenizou a intensidade e a severidade dessas doenças. ...
A safra de primavera-verão 2019/2020 foi
caracterizada pela ocorrência de estiagem em todo Estado do
Rio Grande do Sul, com impactos negativos na agropecuária.
11
Sendo assim, os objetivos desse trabalho foram (1) analisar
as condições meteorológicas do período novembro de 2019 a
março de 2020, com ênfase na precipitação pluvial e
temperatura do ar, (2) relacionando-as ao rendimento e
fitossanidade das principais culturas produtoras de grãos
(milho e soja), bem como ao crescimento das pastagens e ao
desempenho animal (bovinocultura de corte e leite) observado
no período de primavera-verão e (3) promover uma análise
comparativa das safras 2004/2005, 2011/2012 e 2019/2020,
caracterizadas como de ocorrência de estiagens no Estado do
Rio Grande do Sul.
... Two of the most important and widespread fungal pathogens attacking the olive canopy are Venturia oleaginea and Pseudocercospora cladosporioides, responsible for peacock spot and cercosporiosis, respectively [5,6]. Both pathogens cause olive leaf spots, which are frequently difficult to distinguish [7]. Symptoms caused by V. oleaginea mainly start as sooty blotches on the upper surface of leaves that develop into dark green to black circular spots 0.2 to 1 cm in diameter, often surrounded by a yellowish halo around the spot [8][9][10]. ...
... These fungi survive in leaf lesions and spread through conidia, by rain, wind, or insects, which is the main source of inoculum for primary infection in spring [19,20]. Both infections are associated with high humidity and low temperatures [7,19,[21][22][23]. The establishment of several new super intensive olive orchards originates in a greater shading of the trees and favors the conditions for the development of these diseases. ...
Venturia oleaginea and Pseudocercospora cladosporioides are two of the most important olive fungal pathogens causing leaf spots: peacock spot, and cercosporiosis, respectively. In the present study, fungal communities associated with the presence of these pathogens were investigated. Overall, 300 symptomatic and asymptomatic trees from different cultivars were sampled from Alentejo, Portugal. A total of 788 fungal isolates were obtained and classified into 21 OTUs; Ascomycota was clearly the predominant phylum (96.6%). Trees from cultivar ‘Galega vulgar’ showed a significant higher fungal richness when compared to ‘Cobrançosa’, which in turn showed significant higher values than ‘Picual’. Concerning plant health status, symptomatic plants showed significant higher fungal richness, mainly due to the high number of isolates of the pathogens V. oleaginea and P. cladosporioides. In terms of fungal diversity, there were two major groups: ca. 90% of the isolates found in symptomatic plants belonged to V. oleaginea, P. cladosporioides, Chalara sp., and Foliophoma sp. while ca. 90% of the isolates found in asymptomatic plants, belonged to Alternaria sp. and Epicoccum sp. This study highlights the existence of different fungal communities in olive trees, including potential antagonistic organisms that can have a significant impact on diseases and consequently on olive production.
