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Soybean diseases induced by Cercospora spp. exhibit a global prevalence worldwide. Cercospora kikuchii causes both Cercospora leaf blight (CLB) and purple seed stain (PSS), whereas Cercospora sojina is a causal agent of frogeye leaf spot (FLS). Eighteen Cercospora isolates originating from soybean plants exhibiting CLB, PSS, and FLS symptoms were obtained from continental Russia, the Crimea Peninsula, and South America. The identification was based on the Consolidated Species Concept and involved multi-locus phylogenetic analysis, assessment of cercosporin production capacity, and pathogenicity testing. Ten isolates were identified as C. sojina; the eight remaining ones were categorized into seven distinct species. Two isolates of C. kikuchii were obtained from South America, along with a single isolate each of Cercospora cf. sigesbeckiae and Cercospora sp. Q from the Russian Far East and South America, respectively. Three isolates from the Russian Far East were identified as Cercospora cf. alchemillicola and Cercospora celosiae. A single isolate formed a distinct monophyletic clade that did not include ex-type or representative Cercospora strains and is, therefore, considered a candidate for a new Cercospora species. Cercosporin production in vitro is not a stable and reliable feature for species identification; it could vary and depends on factors such as the nutrient medium composition and the specific lighting conditions during the culturing process. In Russia, multiple Cercospora species are associated with PSS: at least C. cf. alchemillicola, C. cf. sigesbeckiae, and C. celosiae, which are new records for Russia. Cercospora kikuchii and Cercospora sp. Q emerge as causal agents of PSS in South America. PSS and CLB symptoms evident on soybeans are intricate features; thus, they can no longer be definitively regarded as unequivocal signs for the presence of C. kikuchii. [ABSTRACT FROM AUTHOR]

Cercospora leaf spot (CLS) disease and bruchids are the common disease and insect pest causing yield loss in mung bean (Vigna radiata (L.) R. Wilczek). ‘KUML4’ is an improved mung bean cultivar grown in Thailand having high yield, early and highly synchronous maturity, large seed size, but susceptible to CLS disease and bruchids. This study was conducted to improve ‘KUML4’ through introgression of VrTAF5 for CLS resistance and VrPGIP2 for bruchid (Callosobruchus maculatus) resistance from landrace mung bean accessions ‘V4718’ and ‘V2808’, respectively, by marker-assisted backcrossing (MABC). In the MABC, foreground selections were performed using VrTAF5- and VrPGIP2-specific markers. The BC3F3 pyramided lines with KUML4 background carrying both VrTAF5 and VrPGIP2 genes were developed and evaluated for agronomic and yield-related traits, CLS resistance, and bruchid resistance. Three BC3F3 lines, KUML4-2020-21, KUML4-2020-23, and KUML4-2020-60, exhibiting superior agronomic and yield-related traits, CLS resistance, and bruchid resistance than ‘KUML4’ were successfully obtained via MABC. Under the CLS outbreak, these lines showed 248.5%-331.7% higher seed yield than ‘KUML4’. The lines expressed nearly perfect resistance to bruchid (< 5% seeds damaged). These lines can be developed into new resistant mung bean cultivars in the future. [ABSTRACT FROM AUTHOR]

Cleistocalyx operculatus is ubiquitous and known by folk experiences for its antimicrobial properties, thus promising as a low-cost green pesticide. In this work, the plant ethanol extract was investigated against Cercospora nicotianae, a pathogenic fungus implicated in the leaf spot in Pennywort. Characterisation of the plant extract showed 21 identifiable constituents (1-21), with the major components: 4',5'-dimethoxy-2'-hydroxy-4-methylchalcone (21; 41.71 %), phytol (15; 8.46 %), and 5.7-dimethoxyflavanone (20; 5.20 %). The in vitro antifungal screening of the extract revealed potent inhibitory capacity up to 7 days after inoculation (concentration = 9.54 mg.mL-1). The inhibitory potential was predicted by docking simulation, i.e., 19-Q6DQW3 (DS -10.7 kcal.mol-1; DSmax -12.7 kcal.mol-1) > 21-Q6DQW3 (DS -10.3 kcal.mol-1; DSmax -11.9 kcal.mol-1) > 20-Q6DQW3 (DS -10.3 kcal.mol-1 ; DSmax -11.7 kcal.mol-1). The chemical potentiality was derived from quantum calculation, i.e., 22 (-1172.77 a.u.) > 21 ≈ 19 (approx. - 1000 a.u.) > 20 (-ca. -950 a.u.) for chemical stability, and 3 (3.40 Debye), 15 (2.47 Debye), and 5 (2.03 Debye) for physical compatibility. The suitability for biological and pesticidal applications was justified by physicochemical analyses. The results revealed a firm correlation between the extracted major constituents (20 and 21) and the total antifungal activity against C. nicotianae, thus encouraging its local usage. [ABSTRACT FROM AUTHOR]

To investigate the microbial diversity and the main pathogenic microorganisms of Fraxinus mandshurica leaves with different degrees of brown spot disease, and to analyze the control methods to maintain the ecological safety and enhance the economic benefits of Fraxinus mandshurica plantation forests, leaves infected with brown spot disease to varying degrees at Maoershan Experimental Forest Farm were collected,and the microbial community structure and species composition of Fraxinus mandshurica leaves were determined and analyzed using high-throughput sequencing technology. A total of 1 026 fungal operational taxonomic units (OUT) and 322 bacterial OUTs were obtained before and after the disease in the three groups of samples. Among the bacteria, the phyla Proteobacteria and Actinobacteriota were the dominant phyla; the genera Sphingomonas, Acidibacter and Bradyrhizobium were the main dominant genera. Among the fungi, the phyla Ascomycota and Basidiomycota were the dominant phyla; the genera Vishniacozyma, Septoria, and Hannaella were the dominant genera. There were no significant differences in bacterial diversity and community structure among the three groups of samples, and significant differences in fungal diversity and community structure. It was preliminarily speculated that the Cercospora was a pathogenic bacterium, but its pathogenicity needed further study. [ABSTRACT FROM AUTHOR]

A serious factor hampering global maize production is gray leaf spot disease. Cercospora zeina is one of the causative pathogens, but population genomics analysis of C. zeina is lacking. We conducted whole-genome Illumina sequencing of a representative set of 30 C. zeina isolates from Kenya and Uganda (East Africa) and Zambia, Zimbabwe, and South Africa (Southern Africa). Selection of the diverse set was based on microsatellite data from a larger collection of the pathogen. Pangenome analysis of the C. zeina isolates was done by (1) de novo assembly of the reads with SPAdes, (2) annotation with BRAKER, and (3) protein clustering with OrthoFinder. A published long-read assembly of C. zeina (CMW25467) from Zambia was included and annotated using the same pipeline. This analysis revealed 790 non-shared accessory and 10,677 shared core orthogroups (genes) between the 31 isolates. Accessory gene content was largely shared between isolates from all countries, with a few genes unique to populations from Southern Africa (32) or East Africa (6). There was a significantly higher proportion of effector genes in the accessory secretome (44%) compared to the core secretome (24%). PCA, ADMIXTURE, and phylogenetic analysis using a neighbor-net network indicated a population structure with a geographical subdivision between the East African isolates and the Southern African isolates, although gene flow was also evident. The small pangenome and partial population differentiation indicated recent dispersal of C. zeina into Africa, possibly from 2 regional founder populations, followed by recurrent gene flow owing to widespread maize production across sub-Saharan Africa. [ABSTRACT FROM AUTHOR]

Copyright of Revista de Ciências Agrárias is the property of Sociedade de Ciencias Agrarias de Portugal and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Pulses are notably good nutritive complements of carbohydrate-rich staple diets, such as, wheat, maize, and rice. Mung bean is an essential pulse crop with different proteins and antioxidants proven beneficial for health. The yield of mung bean in Pakistan is comparable to the world average, but overall production is low because of several biotic and abiotic factors. Cercospora leaf spot (CLS) is one of mung bean's most damaging diseases, limiting its productivity, causing significant losses in yield and an overall gap in production. The presented investigation progressed to comprehending the genetics of resistance to CLS in mung bean. A minicore set of 293 mung bean genotypes developed and maintained by the World Vegetable Center, Taiwan, served as samples in the study. Observed CLS attacks occur during flowering and reduce the yield by decreasing the number of pods per plant. The genetics to resistance against CLS has a single recessive gene controlling it; hence, homozygous recessive plants will be CLS-resistant. Therefore, single gene transfer methods, such as, backcross breeding, are recommendable for incorporating CLS resistance in high-yielding mung bean genotypes. [ABSTRACT FROM AUTHOR]

Cercospora leaf spot disease is one of the most widespread diseases of spinach which is caused by Cercospora beticola Sacc and has posed a serious threat to the successful cultivation of this crop both abroad and in India. A roving survey of major growing areas of spinach was conducted in two Takulas of Bharuch district viz Bharuch and Ankleshwar during first fortnight of September-October (reproductive stage of the crop) in the year 2020-21. It was found that higher disease index of 41.84 per cent was observed in Ankleshwar Taluka as compared to 25.11 per cent in Bharuch Taluka of Bharuch district. [ABSTRACT FROM AUTHOR]

We developed a molecular marker for MAS of mungbean resistant varieties against CLS from the consensus sequence (MB-CLsRG) of identified RGAs (MB-ClsRCaG1 and MB-ClsRCaG2). The MB-CLsRG sequence-specific primer pair was used to screen Cercospora leaf spot (CLS) resistant varieties of mungbean in genomic analysis that showed congruency with phenotypic screening. Validation of molecular marker linkage with CLS resistance was performed using rtPCR in transcriptomic analysis. The sequenced PCR products showed 100% homology with MB-CLsRG sequence and putative disease resistance proteins that confirmed the linkage of molecular marker with CLS resistance in mungbean. The antifungal potential of MB-CLsRG gene encoding protein was assessed. The MB-CLsRG gene sequence was cloned in the E. coli expression vector for recombinant protein production. The recombinant protein was then investigated for its in vitro antifungal potential against Cercospora canescens. The in vitro investigation showed strong antifungal activity of recombinant protein as it restricted the growth of fungal mycelial mass. The results validated the linkage of developed marker with CLS-resistant mungbean varieties; therefore, it can be used to screen resistant varieties from a large population in MAS. Moreover, the recombinant protein of the MB-CLsRG gene sequence revealed antifungal potential, which proved the gene sequence could be suitable to use in transgenic plants technology to develop fungal-resistant transgenic crops. [ABSTRACT FROM AUTHOR]

In this study, the micromorphology and surface details of Pseudocercospora pseudostigmina‐platani conidia were investigated on American sycamore (Platanus occidentalis) leaves. Sooty films were collected from diseased leaves for fungal DNA extraction and observed using light and field‐emission scanning electron microscopy. Two types of conidia were present on the leaves: (i) hyaline and curved Cercostigmina‐like conidia and (ii) brown and straight Stigmina‐like conidia. The fungal pathogen was identified as P. pseudostigmina‐platani based on morphological characteristics and internal transcribed spacer region sequences. Some non‐glandular trichomes were found near the centre of the conidial masses on the abaxial surface of the naturally infected leaves. Leaf ultrasonication to dislodge conidia revealed sporodochia erupting through the stomata. Hyphae from sporodochia grew on the leaf surface and entered host tissues through the stomata. Conidiogenous cells had terminal rings and tapered towards the flat region where a conidium was attached. The conidia produced secondary conidia directly without hyphae. After dislodging the conidia by ultrasonication, scars were observed. These results indicate that the fungus has dimorphic conidia and microcycle conidiation for simple and rapid asexual reproduction. [ABSTRACT FROM AUTHOR]

Maize yields worldwide are limited by foliar diseases that could be fungal, oomycete, bacterial, or viral in origin. Correct disease identification is critical for farmers to apply the correct control measures, such as fungicide sprays. Deep learning has the potential for automated disease classification from images of leaf symptoms. We aimed to develop a classifier to identify gray leaf spot (GLS) disease of maize in field images where mixed diseases were present (18,656 images after augmentation). In this study, we compare deep learning models trained on mixed disease field images with and without background subtraction. Performance was compared with models trained on PlantVillage images with single diseases and uniform backgrounds. First, we developed a modified VGG16 network referred to as "GLS_net" to perform binary classification of GLS, which achieved a 73.4% accuracy. Second, we used MaskRCNN to dynamically segment leaves from backgrounds in combination with GLS_net to identify GLS, resulting in a 72.6% accuracy. Models trained on PlantVillage images were 94.1% accurate at GLS classification with the PlantVillage testing set but performed poorly with the field image dataset (55.1% accuracy). In contrast, the GLS_net model was 78% accurate on the PlantVillage testing set. We conclude that deep learning models trained with realistic mixed disease field data obtain superior degrees of generalizability and external validity when compared to models trained using idealized datasets. [ABSTRACT FROM AUTHOR]

ABSTRACT Draft genomes of the fungal species Ambrosiella cleistominuta, Cercospora brassicicola, C. citrullina, Physcia stellaris, and Teratosphaeria pseudoeucalypti are presented. Physcia stellaris is an important lichen forming fungus and Ambrosiella cleistominuta is an ambrosia beetle symbiont. Cercospora brassicicola and C. citrullina are agriculturally relevant plant pathogens that cause leaf-spots in brassicaceous vegetables and cucurbits respectively. Teratosphaeria pseudoeucalypti causes severe leaf blight and defoliation of Eucalyptus trees. These genomes provide a valuable resource for understanding the molecular processes in these economically important fungi.

Cercospora citrullina, isolated from pumpkin plant (Cucurbita maxima), initially could not produce conidia when cultured on potato dextrose agar, but was able to produce conidia when cultured on oatmeal agar, oat grain agar, wheat grain agar and barley grain agar. C. citrullina also produced conidia when cultured in substrates such as oat grain, wheat grain, barley grain and Trichosanthes sp. dried leaves. Trichosanthes sp. dried leaves induced the highest conidia production (4.81 × 103 conidia / ml) while oatmeal agar and barley grain agar yielded the best result among the agar media by inducing 1.23 × 103 conidia / ml each. Overall, continuous darkness condition was better than other lighting conditions (12 h near UV black light plus 12 h darkness condition; and 12 h fluorescent white light plus 12 h darkness lighting condition). Lastly, inoculation of C. citrullina onto cucurbit plants was successfully conducted by sandwiching inoculum between leaves and plastic cards.

Cercospora leaf spot (CLS), caused by the hemibiotrophic fungus Cercospora beticola , is a destructive disease affecting table beet. Multiple applications of fungicides are needed to reduce epidemic progress to maintain foliar health and enable mechanized harvest. The sustainability of CLS control is threatened by the rapid development of fungicide resistance, the need to grow commercially acceptable yet CLS-susceptible cultivars, and the inability to manipulate agronomic conditions to mitigate disease risk. Nighttime applications of germicidal UV light (UV-C) have recently been used to suppress several plant diseases, notably those caused by ectoparasitic biotrophs such as powdery mildews. We evaluated the efficacy of nighttime applications of UV-C for suppression of CLS in table beet. In vitro lethality of UV-C to germinating conidia increased with increasing dose, with complete suppression at 1,000 J/m 2 . Greenhouse-grown table beet tolerated relatively high doses of UV-C without lethal effects despite some bronzing on the leaf blade. A UV-C dose >1,500 J/m 2 resulted in phytotoxicity severities greater than 50%. UV-C exposure to ≤750 J/m 2 resulted in negligible phytotoxicity. Older (6-week-old) greenhouse-grown plants were more susceptible to UV-C damage than younger (2- and 4-week-old) plants. Suppression of CLS by UV-C was greater when applied within 6 days of C. beticola inoculation than if delayed until 13 days after infection in greenhouse-grown plants. In field trials, there were significant linear relationships between UV-C dose and CLS control and phytotoxicity severity, and a significant negative linear relationship between phytotoxicity and CLS severity at the final assessment. Significant differences between UV-C doses on the severity of CLS and phytotoxicity indicated an efficacious dose near 800 J/m 2 . Collectively, these findings illustrate significant and substantial suppression by nighttime applications of UV-C for CLS control on table beet, with potential for incorporation in both conventional and organic table beet broadacre production systems., Competing Interests: The author(s) declare no conflict of interest.

Leaf spot (Cercospora moricola, Cooke) is a disease that negatively influences the yield of mulberry (Morus alba L.) plants. To determine the effect of nitrogen levels on the incidence and severity of leaf spot an experiment was carried out on mulberry plants. The nitrogen levels included 0, 100, 200 and 300 kg ha-1, which were applied in two splits coinciding with the two rainy seasons. The study design was randomized complete block design (RCBD) with three replications. Determination of disease intensity involved scoring for disease intensity on a 1-5 Manandhar scale and calculation of the disease incidence were performed by expressing the number of infected leaves as a percentage of the total number of leaves. The values were translated to area under disease progress stairs (AUDPS). The means for AUDPS were subjected to analysis of variance (ANOVA) using PRO GLM in SAS and Fisher's least significant difference (LSD) used to partition the means at p=0.05. The results showed that as the rate of nitrogen application was increased, there was a corresponding decrease in AUDPS for disease incidence and a decrease in AUDPS for disease severity. From the obtained results it can be concluded that nitrogen at an application rate of 200 kg ha-1 is an effective approach to suppress Cercospora leaf spot of mulberry and can be recommended to the farmers, where this disease is a problem for cultivation of mulberry. [ABSTRACT FROM AUTHOR]

Cercospora brachiata is a phytopathogenic fungus. To know more about the metabolites produced by this fungus, the objective of this work was to identify, isolate and characterize sub- stances present in extracts of the growth broth and mycelium, using gas chromatography with mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR). It was also objective to evaluate the antibacterial activity of the extracts. Among the compounds identified, fatty acids, esters, and steroids can be highlighted. The main compounds identified are 9-hexadecenoic, hexadecenoic, oleic, octade- canoic, lauric, myristic, palmitic, doceno-13-enoic, stearic, linoleic, and nonadecanoic acids present in almost all extracts. For the antibacterial activity, the broth microdilution method was used. The ethyl acetate extract of the mycelium presented inhibitory concentrations (MICs) against the bacterium Actinomyces naeslundii (100 μg mL−1) and Streptococcus sanguinis (200 μg mL−1). Finally, two steroids were isolated and identified in the hexane extract of mycelium: ergosta-6,22-dien-3β,5α,8α-triol and brassicasterol. [ABSTRACT FROM AUTHOR]

Maize yields worldwide are limited by foliar diseases that could be fungal, oomycete, bacterial, or viral in origin. Correct disease identification is critical for farmers to apply the correct control measures, such as fungicide sprays. Deep learning has the potential for automated disease classification from images of leaf symptoms. We aimed to develop a classifier to identify gray leaf spot (GLS) disease of maize in field images where mixed diseases were present (18,656 images after augmentation). In this study, we compare deep learning models trained on mixed disease field images with and without background subtraction. Performance was compared with models trained on PlantVillage images with single diseases and uniform backgrounds. First, we developed a modified VGG16 network referred to as “GLS_net” to perform binary classification of GLS, which achieved a 73.4% accuracy. Second, we used MaskRCNN to dynamically segment leaves from backgrounds in combination with GLS_net to identify GLS, resulting in a 72.6% accuracy. Models trained on PlantVillage images were 94.1% accurate at GLS classification with the PlantVillage testing set but performed poorly with the field image dataset (55.1% accuracy). In contrast, the GLS_net model was 78% accurate on the PlantVillage testing set. We conclude that deep learning models trained with realistic mixed disease field data obtain superior degrees of generalizability and external validity when compared to models trained using idealized datasets.

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. [ABSTRACT FROM AUTHOR]

BACKGROUND: Metyltetraprole is a new quinone outside inhibitor (QoI) fungicide showing potent activity against QoI‐resistant fungi that possess the G143A cytochrome b mutation, which confers resistance to existing QoIs such as trifloxystrobin. For its sustainable use, monitoring of metyltetraprole sensitivity is necessary and the establishment of appropriate methodology is important in each pathogen species. RESULTS: In Cercospora beticola, the causal agent of sugar beet leaf spot, some isolates were less sensitive to metyltetraprole (EC50 > 1 mg L–1, higher than the saturated concentration) using the common agar plate method, even with 100 mg L−1 salicylhydroxamic acid, an alternative oxidase inhibitor. However, microtiter tests (EC50 < 0.01 mg L−1), conidial germination tests (EC50 < 0.01 mg L−1) and in planta tests (>80% control at 75 mg L−1 run‐off spraying) confirmed that all tested isolates were highly sensitive to metyltetraprole. For trifloxystrobin, G143A mutants were clearly resistant upon microtiter plate tests (median EC50 > 2 mg L−1) and distinct from wild‐type isolates (median EC50 < 0.01 mg L−1). Notably, mycelium fragments were usable for the microtiter plate tests and the test was applicable for isolates that do not form sufficient conidia. Our monitoring study by microtiter plate tests did not indicate the presence of metyltetraprole‐resistant C. beticola isolates in populations in Hokkaido, Japan. CONCLUSION: The microtiter tests were revealed to be useful for monitoring the sensitivity of C. beticola to metyltetraprole and trifloxystrobin. © 2020 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Gray leaf spot (GLS) disease in maize, caused by the fungus Cercospora zeina, is a threat to maize production globally. Understanding the molecular basis for quantitative resistance to GLS is therefore important for food security. We developed a de novo assembly pipeline to identify candidate maize resistance genes. Near-isogenic maize lines with and without a QTL for GLS resistance on chromosome 10 from inbred CML444 were produced in the inbred B73 background. The B73-QTL line showed a 20% reduction in GLS disease symptoms compared to B73 in the field (p = 0.01). B73-QTL leaf samples from this field experiment conducted under GLS disease pressure were RNA sequenced. The reads that did not map to the B73 or C. zeina genomes were expected to contain novel defense genes and were de novo assembled. A total of 141 protein-coding sequences with B73-like or plant annotations were identified from the B73-QTL plants exposed to C. zeina. To determine whether candidate gene expression was induced by C. zeina, the RNAseq reads from C. zeina-challenged and control leaves were mapped to a master assembly of all of the B73-QTL reads, and differential gene expression analysis was conducted. Combining results from both bioinformatics approaches led to the identification of a likely candidate gene, which was a novel allele of a lectin receptor-like kinase named L-RLK-CML that (i) was induced by C. zeina, (ii) was positioned in the QTL region, and (iii) had functional domains for pathogen perception and defense signal transduction. The 817AA L-RLK-CML protein had 53 amino acid differences from its 818AA counterpart in B73. A second “B73-like” allele of L-RLK was expressed at a low level in B73-QTL. Gene copy-specific RT-qPCR confirmed that the l-rlk-cml transcript was the major product induced four-fold by C. zeina. Several other expressed defense-related candidates were identified, including a wall-associated kinase, two glutathione s-transferases, a chitinase, a glucan beta-glucosidase, a plasmodesmata callose-binding protein, several other receptor-like kinases, and components of calcium signaling, vesicular trafficking, and ethylene biosynthesis. This work presents a bioinformatics protocol for gene discovery from de novo assembled transcriptomes and identifies candidate quantitative resistance genes.

The early and late blight are important diseases of peanut. The reactions of eleven peanut genotypes Arachis hypogea L. and one local cultivar (cv. Goli) to Cercospora leaf spot (CLS) diseases were evaluated under CLS high incidence field conditions during 2016. The field experiment was conducted in Lasht-e Nesha Agricultural Research Station (north-east of Rasht) in 2016 using randomized complete block design with four replications. The results indicated a possible differential reaction to infection by the fungi Passalora arachidicola and P. personata among genotypes of peanut. There was a significant variability among peanut genotypes to CLS diseases (P ≤ 0.01). The differences between susceptible and resistant genotypes were identified by the number and size of spots produced per leaf (leaflets), leaf defoliation, and leaf spot severity percentage. Mean comparisons revealed that Cercospora leaf spot incidence in terms of the number of spots per leaf were greater in the Pn202 (85.1) and Pn220 (75.8) by a factor of about 5- to 8-fold relative to the Pn213 (9.2), Pn170 (10.9), Pn140 (11.6), and Pn204 (15.2) genotypes. When the severity of Cercospora leaf spot disease was considered, this difference was 3-5-fold. The defoliation and severity of CLS percentage on genotypes of peanut were ranged 4.7-60.9% and 11.3-52.5%, respectively. Accordingly, the defoliation and severity of CLS were observed as high as 60.88% and 52.49% on Pn202 peanut genotype, respectively. Our results revealed that with increasing CLS severity from 11.3 to 52.5% (41.2%), defoliation increased from 4.7 to 60.9% (56.2%) while the pod yield decreased from 3809.4 to 1217.6 kg/h (2591.8 kg/h). In total, three genotypes (Pn170, Pn140, and Pn213) were moderately resistant, while genotypes Pn220 and Pn202 were susceptible to CLS diseases. The resistant genotypes indicated favorable agronomic characteristics and had a potential to be released as commercial cultivars or to be used as parents in peanut breeding programs.

The aim of this work was to study the fungal diversity in Paspalum notatum, in order to determine the potential biological control of disease-causing pathogens and their effects on growth promotion. Two isolates of Cercospora dianellicola were identified from asymptomatic P. notatum leaves, as an endophytic species. The possible benefits for the host plant remain to be analyzed. [ABSTRACT FROM AUTHOR]

We developed models for simulating trends over time as functions of the thermal index and models for estimating the levels of infestation of the coffee leaf miner and coffee berry borer and the severity of disease for coffee leaf rust and cercospora, the main phytosanitary problems in coffee crops around the world. We used historical series of climatic data and levels of pest infestation and disease severity in Coffea arabica for high and low yields for seven locations in the two main coffee-producing regions in the state of Minas Gerais in Brazil, Sul de Minas Gerais and Cerrado Mineiro. We conducted two analyses: (a) we simulated the trends of the progress of diseases and pests over time using non-linear models. We only used the thermal index because air temperature is commonly measured by farmers in the regions. (b) We estimated the levels of pest infestation and disease severity using multiple linear regression, with the levels of diseases and pests as dependent variables and accumulated degree days (DD), coffee foliage (LF) estimated by DD and the number of nodes (NN) estimated by DD as independent variables. We used DD and LF = f (DD) and NN = f (DD) to predict diseases and pests with accuracy. MAPEs were 19.6, 5.7, 9.5, and 15.8% for rust, cercospora, leaf miner, and berry borer, respectively, for Sul de Minas Gerais. Establishing phytosanitary alerts using only air temperature was possible with these models. [ABSTRACT FROM AUTHOR]

Gray leaf spot (GLS) disease in maize, caused by the fungus Cercospora zeina , is a threat to maize production globally. Understanding the molecular basis for quantitative resistance to GLS is therefore important for food security. We developed a de novo assembly pipeline to identify candidate maize resistance genes. Near-isogenic maize lines with and without a QTL for GLS resistance on chromosome 10 from inbred CML444 were produced in the inbred B73 background. The B73-QTL line showed a 20% reduction in GLS disease symptoms compared to B73 in the field (p = 0.01). B73-QTL leaf samples from this field experiment conducted under GLS disease pressure were RNA sequenced. The reads that did not map to the B73 or C. zeina genomes were expected to contain novel defense genes and were de novo assembled. A total of 141 protein-coding sequences with B73-like or plant annotations were identified from the B73-QTL plants exposed to C. zeina. To determine whether candidate gene expression was induced by C. zeina , the RNAseq reads from C. zeina -challenged and control leaves were mapped to a master assembly of all of the B73-QTL reads, and differential gene expression analysis was conducted. Combining results from both bioinformatics approaches led to the identification of a likely candidate gene, which was a novel allele of a lectin receptor-like kinase named L-RLK-CML that (i) was induced by C. zeina , (ii) was positioned in the QTL region, and (iii) had functional domains for pathogen perception and defense signal transduction. The 817AA L-RLK-CML protein had 53 amino acid differences from its 818AA counterpart in B73. A second "B73-like" allele of L-RLK was expressed at a low level in B73-QTL. Gene copy-specific RT-qPCR confirmed that the l-rlk-cml transcript was the major product induced four-fold by C. zeina. Several other expressed defense-related candidates were identified, including a wall-associated kinase, two glutathione s-transferases, a chitinase, a glucan beta-glucosidase, a plasmodesmata callose-binding protein, several other receptor-like kinases, and components of calcium signaling, vesicular trafficking, and ethylene biosynthesis. This work presents a bioinformatics protocol for gene discovery from de novo assembled transcriptomes and identifies candidate quantitative resistance genes. [ABSTRACT FROM AUTHOR]

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Fungal diseases cause a lot of economic damage in castor and in some instances; it is a limiting factor to commercial cultivation of the crop. In the present study, survey on castor germplasm for sources of resistant genes to Cercospora leaf spot was carried out at National Cereals Research Institute Badeggi, Nigeria. The genotypes were grown in a resolvable incomplete block design with three replications. The results obtained revealed high variability of host resistance among the genotypes. Percentage disease incidence ranged between 16.67% and 100%. A range between 1.43 score and 4.17 scores with average score of 2.89 were recorded for disease severity among the genotypes. Highest (95.92%) and lowest (13.03%) damage index were observed in the genotypes Acc. 059 and Acc. 022 respectively. The Principal component (PC) 1 to 4 explained 100% of the variability in the germplasm. PC1 explained 69.72% of the variability with the major contributory parameters being the disease incidence, severity and damage index. Significant negative correlations were recorded between the seed yield and all the three disease indices. The result of cluster analysis revealed six cluster groups among the germplasm with cluster membership ranging between 4 and 40 members. The cluster I contained members (Acc. 002, Acc. 017, Acc. 022, Acc. 026, Acc. 027, Acc. 048 and Acc. 061) with low average disease incidence, severity and damage index. The results reported here could serve as a basis for further screening of the potential resistant genotypes under controlled condition to develop resistant lines.

Cercospora leaf blight (CLB) of soybean, caused by Cercospora cf. flagellaris , C. kikuchii , and C. cf. sigesbeckiae , is an economically important disease in the southern United States. Cultivar resistance to CLB is inconsistent; therefore, fungicides in the quinone outside inhibitor (QoI) class have been relied on to manage the disease. Approximately 620 isolates from plants exhibiting CLB were collected between 2018 and 2021 from 19 locations in eight southern states. A novel polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay based on two genes, calmodulin and histone h3 , was developed to differentiate between the dominant species of Cercospora , C. cf. flagellaris , and C. cf. sigesbeckiae . A multilocus phylogenetic analysis of actin, calmodulin, histone h3, ITS rDNA, and transcription elongation factor 1-α was used to confirm PCR-RFLP results and identify remaining isolates. Approximately 80% of the isolates collected were identified as C. cf. flagellaris , while 15% classified as C. cf. sigesbeckiae , 2% as C. kikuchii , and 3% as previously unreported Cercospora species associated with CLB in the United States. PCR-RFLP of cytochrome b ( cytb ) identified QoI-resistance conferred by the G143A substitution. Approximately 64 to 83% of isolates were determined to be QoI-resistant, and all contained the G143A substitution. Results of discriminatory dose assays using azoxystrobin (1 ppm) were 100% consistent with PCR-RFLP results. To our knowledge, this constitutes the first report of QoI resistance in CLB pathogen populations from Alabama, Arkansas, Kentucky, Mississippi, Missouri, Tennessee, and Texas. In areas where high frequencies of resistance have been identified, QoI fungicides should be avoided, and fungicide products with alternative modes-of-action should be utilized in the absence of CLB-resistant soybean cultivars., Competing Interests: The author(s) declare no conflict of interest.

We propose a new mathematical model based on differential equations to investigate the transmission and spread of frogeye leaf spot, a major soybean disease caused by the fungus Cercospora sojina. The model incorporates the primary and secondary transmission routes of the disease as well as the intrinsic dynamics of the pathogen in the contaminated soil. We conduct detailed equilibrium and stability analyses for this model using theories of dynamical systems. We additionally conduct numerical simulations to verify the analytical predictions and to implement the model for a practical application.

An extensive and intensive survey was conducted in the forests, fields, plantations and nurseries of Jalgaon district in order to collect micro fungi and follicolous fungi. About eighty disease were found in the different plant trees of the district. These genera were Astromella - Pseudocercospora, Mycocentrospora, Cercospora, Phoma, Ravanelia Stigmina, Scolecostigmina, Mycovellosiella., Passalora, and Pestalotiopsis, Rhytisma, Sirosporium etc. They caused different type of pathological symptoms like necrosis, brown spots, black spots and shot hole formation. Most of the disease symptoms starts during the rainy season and continue upto February-March. Some of the disease prolong December-January. They cause serious disease and responsible for pre-mature defoliation. [ABSTRACT FROM AUTHOR]

Niger (Guizotia abyssinica Cass.) is an important minor oil seed crop grown in dry areas grown mostly by tribal and interior places as life line of tribal segment. Tribal people mainly use its oil for cooking purpose, above than that there were also other uses. Hence, the niger crop should be protected from the infection. The crop is affected by number of fungal diseases. Therefore, a field experiment was formulated for three years with the four replications at the Niger Research Station (NRS) at Navsari Agricultural University (NAU), Vanarasi, Navsari (Gujarat) on the foliar diseases of GN-1 variety of niger crop. In this experiment, six different fungicides along with one control have been evaluated to control the Alternaria and Cercospora leaf spot diseases, out of which all the fungicidal treatments were significantly superior over the control. Here, foliar spray on the incidence of diseases was compared with the control (without any treatment). All the fungicidal treatments were significantly superior over the control to reduce Alternaria and Cercospora leaf spot diseases of Niger crop. Treatment of Carbendazim + Mancozeb (0.2 %) with two sprays first from the initiation of the disease and second after the interval of 15 days recorded the lowest incidence of Alternaria (14.56) and Cercospora (14.94) leaf spot diseases of niger and recorded the highest seed yield 337 seed yield kg/ha along with the net return with cost benefit ratio graph. [ABSTRACT FROM AUTHOR]

The South American vine Araujia hortorum (Apocynaceae) is now considered an invasive species in many countries. In New Zealand it has been targeted for biological control. In its native range in Argentina it is frequently affected by cercosporoid fungi but little is known about the diseases they cause. These pathogens produce no, or scarce, conidia on common artificial media thus hindering certain experimental studies such as pathogenicity and host range tests. We developed a technique to obtain abundant sporulation of two cercosporoid species isolated from diseased leaves of this host. Sporulation was studied and compared on several artificial culture media after different incubation periods. The best results were obtained on a medium prepared with a decoction of the leaves of the host and the addition of CaCO3, after an incubation period of eight days at 25°C for Cercospora sp. and after five days at 20°C for Pseudocercospora fumosa. It is expected the new medium may prove useful for other cercosporoid pathogens as well, at least for those affecting related hosts in the Apocynaceae. [ABSTRACT FROM AUTHOR]

• Cercospora sp. was identified as a source of proteasome activators. • Three Polyketides were isolated, identified and tested in vitro for their effect on proteasome. • Fulvic acid showed an activation effect on 26S proteasome. • Production of fulvic acid in submerged bioreactor was optimized at 162.3 mg of fulvic acid/L. From a large screening of microbial extracts for the discovery of proteasome modulating natural products, the fungal strain Cercospora sp. (CF-223709) was selected as the most promising for further investigation. Different liquid cultures of the strain were initially screened for their anti-oxidant activity (DPPH, ABTS) and for their cytotoxicity against the A2058, HepG2 and CCD25sk cell lines. A detailed chemical analysis and evaluation of the capacity to activate 26S-proteasome was followed for the most active extract. Three main polyketides were isolated and characterized by extensive analysis of NMR and HRMS spectra data as penialidine F (1), fulvic acid (2), and SB238569 (3). Fulvic acid showed the most significant anti-oxidant activity. Its IC 50 value (8.16 μM) against the ABTS radical resulted 3 -fold lower than the standard trolox. Fulvic acid also demonstrated a significant effect on proteasome by enhancing the chymotrypsin- and caspase-like activities of the 26S proteasome of human fibroblasts by 71.43% and 37.5% at 1 μM, respectively. Furthermore by scaling up the culture in a 30 L submerged bioreactor, Cercospora sp. produced up to 162.6 ± 1.3 mg of fulvic acid/L. Our findings suggest that CF-223709 can be a promising source of proteasome activating natural compounds. [ABSTRACT FROM AUTHOR]

An automatic coffee plant disease recognition system is required since coffee is an important commodity in the world economy and its productivity and quality are affected by diseases such as Cercospora and Rust. This research aims to apply computational methods to recognize main diseases in coffee leaves, with the purpose to implement an expert system to assist coffee producers in disease diagnosis during its initial stages. Since these two diseases are shapeless, it inspires a texture attribute extraction approach for pattern recognition. Two texture attributes were considered in this work: statistical attributes and local binary patterns. The texture attribute vector were computed for a collection of images of coffee leaves and used as input to a feedforward neural network. The results were compared with the recognition rate of a convolutional neural network with deep learning applied directly to the same collection of images, without extraction of texture attributes. Surprisingly, this second approach showed better results than the texture extraction method. It could be explained by the small number of diseases we aimed to recognize and a sufficient number of training samples used during the deep learning process. The best Kappa coefficient obtained was 0.970, and sensitivity was 0.980. [ABSTRACT FROM AUTHOR]

Fungal diseases cause a lot of economic damage in castor and in some instances; it is a limiting factor to commercial cultivation of the crop. In the present study, survey on castor germplasm for sources of resistant genes to Cercospora leaf spot was carried out at National Cereals Research Institute Badeggi, Nigeria. The genotypes were grown in a resolvable incomplete block design with three replications. The results obtained revealed high variability of host resistance among the genotypes. Percentage disease incidence ranged between 16.67% and 100%. A range between 1.43 score and 4.17 scores with average score of 2.89 were recorded for disease severity among the genotypes. Highest (95.92%) and lowest (13.03%) damage index were observed in the genotypes Acc. 059 and Acc. 022 respectively. The Principal component (PC) 1 to 4 explained 100% of the variability in the germplasm. PC1 explained 69.72% of the variability with the major contributory parameters being the disease incidence, severity and damage index. Significant negative correlations were recorded between the seed yield and all the three disease indices. The result of cluster analysis revealed six cluster groups among the germplasm with cluster membership ranging between 4 and 40 members. The cluster I contained members (Acc. 002, Acc. 017, Acc. 022, Acc. 026, Acc. 027, Acc. 048 and Acc. 061) with low average disease incidence, severity and damage index. The results reported here could serve as a basis for further screening of the potential resistant genotypes under controlled condition to develop resistant lines. [ABSTRACT FROM AUTHOR]

The study aimed to identify novel antagonistic microorganisms suitable for biological control of diseases in vegetables grown under tropical conditions. Forty seven Bacillus strains were isolated from rhizosphere soils of Trinidad and they were identified as B. amyloliquefaciens, B. subtilis, B. pumilus, B. cereus, B. megaterium, B. mycoides, B. aryabhattai based on 16S rRNA gene analysis. All Bacillus strains were screened for antibiotic lipopeptide genes viz., Iturin A synthetase C (ituC), Iturin A synthetase D (ituD), Bacillomycin D synthetase (BmyB), Bacilysin synthetase A (bacA), Fengycin synthetase (fenD), Surfactin (SrfC) and Zwittermycin A (ZmA). The study revealed the presence of iturin, bacillomycin, bacilysin, fengycin, surfactin and zwittermycin synthesizing genes in B. amyloliquefaciens, B. cereus, B. megaterium and B. pumilus strains. Testing of different Bacillus species against vegetable pathogens revealed greater antagonistic activity of lipopeptide producing B. amyloliquefaciens strains as compared with non-producers. Phylogenetic analysis of Bacillus species based on 16S rRNA gene clearly distinguished the lipopeptide producers from non-lipopeptide producers. The lipopeptide activity and biocontrol potential of B. amyloliquefaciens strains were further demonstrated in lettuce plants against Cercospora leaf spot under a protected cultivation system as a model. The study provided evidence for the biocontrol potential of lipopeptide producing B. amyloliqufaciens strains in the control of disease causing agents in vegetables. These results are promising for the development of bioagents suitable for disease management in tropical conditions. [ABSTRACT FROM AUTHOR]

Highlights • Farming systems influence population genetics of C. zeina. • High microsatellite allele diversity in Cercospora zeina ; gray leaf spot pathogen of maize. • Higher genetic diversity of C. zeina in smallholder compared to commercial maize farms. • Partial population differentiation between smallholder and commercial farms. • Greater clonality and linkage disequilibrium, biased mating type ratios in commercial farms. Abstract Gray leaf spot (GLS) is an important foliar disease of maize. This disease, caused by Cercospora zeina, is prevalent in both smallholder and commercial maize farms in South Africa. Notably, smallholder practices are geared towards conservation agriculture, planting diverse maize genotypes within a field and avoiding chemical control. This study examined the population genetic structure of 129 C. zeina isolates from three smallholder farm sites in KwaZulu-Natal in South Africa using 13 microsatellite markers. These were analysed, together with 239 isolates previously analysed from four commercial farms in the same province, to determine whether farming systems influence the genetic diversity of C. zeina. In addition, we wanted to determine whether the smallholder farming system harboured a greater diversity of C. zeina haplotypes due to lack of chemical spraying of these crops. Overall, farming systems exhibited partial, but significant, population differentiation, contributing 10% of the genetic variation observed. A 16% genetic variation conferred between KwaNxamalala (smallholder) and Cedara (commercial) areas that are in close proximity, confirmed this. Private alleles accounted for 29% of the 52 alleles observed in smallholder farms. Smallholder farms harboured a higher gene and genotypic diversity, with a clonal fraction of only 13% compared to 32% in commercial farms. Mating type ratios indicative of sexual recombination and lower linkage disequilibrium in most smallholder populations were consistent with higher levels of diversity. This study suggests that commercial farming practices, such as fungicides and monoculture crop planting, may result in a narrower genetic diversity of the pathogen that is then propagated by asexual reproduction. In contrast, management of GLS disease in smallholder farms should consider the greater diversity of pathogen genotypes, especially if future research shows that this equates to a greater diversity of pathogenicity alleles. [ABSTRACT FROM AUTHOR]

Pseudocercospora fijiensis, causal agent of black Sigatoka of banana, produces polyketide synthase (PKS) pathways shown to be important in disease development by related Dothideomycete fungi. Genome analysis of the P. fijiensis PKS8-1 gene identified it as part of a gene cluster including genes encoding two transcription factors, a regulatory protein, a glyoxylase/beta-lactamase-like protein, an MFS transporter, a cytochrome P450, two aldo/keto reductases, a dehydrogenase, and a decarboxylase. Genome analysis of the related pathogens Pseudocercospora musae, Pseudocercospora eumusae, and Pseudocercospora pini-densiflorae, identified orthologous clusters containing a nearly identical combination of genes. Phylogenetic analysis of PKS8-1 identified homology to PKS proteins in the monodictyphenone and cladofulvin pathways in Aspergillus nidulans and Cladosporium fulvum, respectively. Analysis of clustered genes showed that the PKS8-1 cluster shares genes for enzymes involved in the production of the emodin intermediate in the monodictyphenone and cladofulvin pathways, but differs in many genes, suggesting production of a different metabolic product. Time course analysis of gene expression in infected banana showed up-regulation of PKS8-1 and four of eight clustered genes as early as 2 weeks post-inoculation and remaining high through 9 weeks. Overexpression of the pathway through constitutive expression of an aflR-like transcription factor gene in the cluster resulted in increased expression in culture of PKS8-1 as well as the four clustered genes that are up-regulated in infected plants. No differences were seen in timing or severity of disease symptoms with the overexpression strains relative to controls, however gene expression analysis showed no difference in expression in planta by an overexpression strain relative to controls. Thus constitutive expression of the aflR-like gene is not sufficient to upregulate the pathway above normal expression in planta. Pathway expression during all phases of disease development and conservation of the pathway in related Pseudocercospora species support a role for this pathway in disease. [ABSTRACT FROM AUTHOR]

Cercospora leaf spot (CLS), caused by Cercospora beticola, is the most detrimental disease of sugar beet in temperate climates. In the Great Lakes region, CLS was well managed by pyraclostrobin-based programmes using the decision support tool BEETcast™. Due to C. beticola resistance to pyraclostrobin in the region, other groups of fungicides were evaluated. Field experiments were conducted at six sites from 2013 to 2015 in Pain Court (PC) and Ridgetown (RT), Ontario. BEETcast™ application schedules for prothioconazole and mancozeb as well as carrier volume (115 and 235 L ha−1) were compared with label-based (calendar) applications. When disease intensity was high, the conservative calendar application schedule reduced the standardized area under the disease progress curve (sAUDPC) by an average of 84% compared with all BEETcast™ schedules, and the BEETcast™ 50/35 schedule (235 L ha−1) reduced sAUDPC by 48% compared with the 55/50 schedules. However, there were fewer differences among application schedules at sites with low or moderate disease intensity. BEETcast™ application schedules reduced the number of fungicide applications by 34-55%. All application schedules increased sucrose (%) and recoverable white sugar (RWS) to an equivalent level, but none of the schedules increased profit margin compared with the non-treated control. Using a carrier volume of 235 L ha−1 reduced sAUDPC by 28% compared with 115 L ha−1 at one site when disease severity exceeded 95% in non-treated control plots. Thus, management recommendations should consider that CLS severity is reduced by application schedules using a shortened interval and appropriate carrier volume, but this does not necessarily result in higher beet or sucrose yield or increases in profit margin. [ABSTRACT FROM AUTHOR]