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This study elucidates the causative agent of a leaf spot in Commelina benghalensis, grown nearby a tomato field, through a polyphasic approach. Pathogenicity of the causative agent to C. benghalensis and cross infectivity to tomato was performed. Morphological, cultural, and molecular characterization identified the fungal isolate as Corynespora cassiicola. C. cassiicola CB005 produced leaf spot symptoms to C. benghalensis and tomato in all three independent trials. The same fungus was reisolated from the inoculated leaves and thus, confirming Koch's postulate. Together, C. cassiicola was identified as the causative agent of a leaf spot in C. benghalensis, which is the first record from the Philippines, and was pathogenic to tomato. The fungus' survival in C. benghalensis, an invasive weed, poses a problem to nearby crops on the next cropping season. Hence, the removal of this weed is important in reducing the source of inoculum in the field. It would be worthwhile to further study other potential plant hosts of C. benghalensis in the Philippines and select for resistance to target leaf spot in tomato cultivars and breeding lines. [ABSTRACT FROM AUTHOR]

Simple Summary: The CsROP gene plays a critical role in the regulation of defense responses. We cloned the cucumber genes CsROP5 and CsROP10 and identified their structure domains containing two Rho-related guanosine triphosphatases. The CsROP5 and CsROP10 genes negatively contributed to defense resistance to Corynespora cassiicola by regulating the ROS signaling pathway, the ABA signaling pathway, and the PR gene. The cloning of resistance-related genes CsROP5/CsROP10 and the analysis of their mechanism of action provide a theoretical basis for the development of molecular breeding of disease-resistant cucumbers. The structure domains of two Rho-related guanosine triphosphatases from plant (ROP) genes were systematically analyzed using the bioinformatics method in cucumber plants, and the genes CsROP5 (Cucsa.322750) and CsROP10 (Cucsa.197080) were cloned. The functions of the two genes were analyzed using reverse-transcription quantitative PCR (RT-qPCR), virus-induced gene silencing (VIGS), transient overexpression, cucumber genetic transformation, and histochemical staining technology. The conserved elements of the CsROP5/CsROP10 proteins include five sequence motifs (G1-G5), a recognition site for serine/threonine kinases, and a hypervariable region (HVR). The knockdown of CsROP10 through VIGS affected the transcript levels of ABA-signaling-pathway-related genes (CsPYL, CsPP2Cs, CsSnRK2s, and CsABI5), ROS-signaling-pathway-related genes (CsRBOHD and CsRBOHF), and defense-related genes (CsPR2 and CsPR3), thereby improving cucumber resistance to Corynespora cassiicola. Meanwhile, inhibiting the expression of CsROP5 regulated the expression levels of ROS-signaling-pathway-related genes (CsRBOHD and CsRBOHF) and defense-related genes (CsPR2 and CsPR3), thereby enhancing the resistance of cucumber to C. cassiicola. Overall, CsROP5 and CsROP10 may participate in cucumber resistance to C. cassiicola through the ROS and ABA signaling pathways. [ABSTRACT FROM AUTHOR]

Corynespora leaf fall disease caused by the fungus Corynespora cassiicola is a major leaf disease of Hevea brasiliensis, the commercial source of natural rubber. Different clones of H. brasiliensis show varying levels of sensitivity towards different strains of C. cassiicola. The genetic mechanism behind the differential sensitivity of H. brasiliensis clones has to be identified in order to develop clones resistant to wider range of C. cassiicola strains. The available information on the sensitivity of H. brasiliensis clones is based on the observation of natural infection or infection of detached leaves. In the present study, the sensitivity of seven H. brasiliensis clones towards two strains of C. cassiicola belonging to two different races was determined using a more precise method by artificial infection of the plants under controlled conditions. Strain CLN 16 was found to be more virulent compared with CSB 16, as it induced more severe symptoms in a shorter period. Among the four different stages of leaves, Stage II leaves with copper brown to apple green colour showed higher sensitivity to both strains followed by Stage III leaves with apple green appearance. Among the clones, RRIM 600 had a higher susceptibility towards CSB 16; however, it was the most resistant clone towards CLN 16. Clone PB 350 showed the highest susceptibility towards CLN 16 whereas RRIM 928 showed the highest resistance towards CSB 16. The present study provides a platform for further studies leading to the development of H. brasiliensis clones with resistance towards wider range of C. cassiicola strains. [ABSTRACT FROM AUTHOR]

Plants respond to biotic and abiotic pressures by changing their biophysical and biochemical aspects, such as reducing their biomass and developing chlorosis, which can be readily identified using remote-sensing techniques applied to the VIS/NIR/SWIR spectrum range. In the current scenario of agriculture, production efficiency is fundamental for farmers, but diseases such as target spot continue to harm soybean yield. Remote sensing, especially hyperspectral sensing, can detect these diseases, but has disadvantages such as cost and complexity, thus favoring the use of UAVs in these activities, as they are more economical. The objectives of this study were: (i) to identify the most appropriate input variable (bands, vegetation indices and all reflectance ranges) for the metrics assessed in machine learning models; (ii) to verify whether there is a statistical difference in the response of NDVI (normalized difference vegetation index), grain weight and yield when subjected to different levels of severity; and (iii) to identify whether there is a relationship between the spectral bands and vegetation indices with the levels of target spot severity, grain weight and yield. The field experiment was carried out in the 2022/23 crop season and involved different fungicide treatments to obtain different levels of disease severity. A spectroradiometer and UAV (unmanned aerial vehicle) imagery were used to collect spectral data from the leaves. Data were subjected to machine learning analysis using different algorithms. LR (logistic regression) and SVM (support vector machine) algorithms performed better in classifying target spot severity levels when spectral data were used. Multivariate canonical analysis showed that healthy leaves stood out at specific wavelengths, while diseased leaves showed different spectral patterns. Disease detection using hyperspectral sensors enabled detailed information acquisition. Our findings reveal that remote sensing, especially using hyperspectral sensors and machine learning techniques, can be effective in the early detection and monitoring of target spot in the soybean crop, enabling fast decision-making for the control and prevention of yield losses. [ABSTRACT FROM AUTHOR]

Although rare, trans-kingdom infection features an interesting infection biology concept, in which highly versatile pathogenic attributes allow successful infections in evolutionarily highly divergent species. Corynespora cassiicola is a phytopathogenic fungus and occasionally causes human infections. Herein, we report a phaeohyphomycosis case caused by C. cassiicola. Given that sporadic reports may contribute to a lack of awareness of the transmission route, clinical manifestations, and diagnostic and clinical management, we systematically reviewed the cases reported thus far. Nine patients were identified and included in the pooled analysis, 88.9% (8/9) of whom were reported after 2010. All patients were from Asian, African, and Latin American countries, among whom 77.8% (7/9) were farmers or lived in areas with active agriculture. Exposed body parts were the major affected infection area, and clinical manifestations were mainly non-specific inflammatory reactions. Although biochemical and morphological examinations confirmed the presence of fungal infection, molecular analysis was used for the final diagnosis, with 77.8% (7/9) being identified by internal transcribed spacer sequencing. Whereas voriconazole, terbinafine, and AmB, either alone or in combination, resulted in successful infection resolution in most cases (5/9; 55.5%), those suffering from invasive facial infections and CARD9 deficiency showed poor outcomes. Our patient is the third case of invasive facial infection caused by C. cassiicola and was successfully treated with intravenous LAmB followed by oral voriconazole combined with topical antifungal irrigation. Molecular identification of fungus and prompt antifungal treatment is pivotal in the clinical success of patients suspected to have phaeohyphomycosis. Moreover, as evidenced by our data, itraconazole treatment is not recommended. [ABSTRACT FROM AUTHOR]

Cucumber leaf spot (CLS), caused by Corynespora cassiicola, is a serious disease of greenhouse cucumbers. With frequent use of existing fungicides, C. cassiicola has developed resistance to some of them, with serious implications for the control of CLS in the field. With a lack of new fungicides, it is necessary to use existing fungicides for effective control. Therefore, this study monitored the resistance of C. cassiicola to three commonly used and effective fungicides, boscalid, trifloxystrobin, and carbendazim, from 2017 to 2021. The frequency of resistance to boscalid showed an increasing trend, and the highest frequency was 85.85% in 2020. The frequency of resistance to trifloxystrobin was greater than 85%, and resistance to carbendazim was maintained at 100%. Among these fungicides, strains with multiple resistance to boscalid, trifloxystrobin, and carbendazim were found, accounting for 32.00, 25.25, 33.33, 43.06, and 37.24%, respectively. Of the strains that were resistant to boscalid, 87% had CcSdh mutations, including seven genotypes: B-H278L/Y, B-I280V, C-N75S, C-S73P, D-D95E, and D-G109V. Also, six mutation patterns of the Ccß-tubulin gene were detected: E198A, F167Y, E198A&M163I, E198A&F167Y, M163I&F167Y, and E198A&F200C. Detection of mutations of the CcCytb gene in resistant strains showed that 98.8% were found to have only the G143A mutation. A total of 27 mutation combinations were found and divided into 14 groups for analysis. The resistance levels differed according to genotype. The development of genotypes showed a complex trend, increasing from 4 in 2017 to 13 in 2021 and varying by region. Multiple fungicide resistance is gradually increasing. Therefore, it is necessary to understand the types of mutations and the trend of resistance to guide the use of fungicides to achieve disease control. [ABSTRACT FROM AUTHOR]

Background: Corynespora leaf spot is a common leaf disease occurring in sesame, and the disease causes leaf yellowing and even shedding, which affects the growth quality of sesame. At present, the mechanism of sesame resistance to this disease is still unclear. Understanding the resistance mechanism of sesame to Corynespora leaf spot is highly important for the control of infection. In this study, the leaves of the sesame resistant variety (R) and the sesame susceptible variety (S) were collected at 0–48 hpi for transcriptome sequencing, and used a combined third-generation long-read and next-generation short-read technology approach to identify some key genes and main pathways related to resistance. Results: The gene expression levels of the two sesame varieties were significantly different at 0, 6, 12, 24, 36 and 48 hpi, indicating that the up-regulation of differentially expressed genes in the R might enhanced the resistance. Moreover, combined with the phenotypic observations of sesame leaves inoculated at different time points, we found that 12 hpi was the key time point leading to the resistance difference between the two sesame varieties at the molecular level. The WGCNA identified two modules significantly associated with disease resistance, and screened out 10 key genes that were highly expressed in R but low expressed in S, which belonged to transcription factors (WRKY, AP2/ERF-ERF, and NAC types) and protein kinases (RLK-Pelle_DLSV, RLK-Pelle_SD-2b, and RLK-Pelle_WAK types). These genes could be the key response factors in the response of sesame to infection by Corynespora cassiicola. GO and KEGG enrichment analysis showed that specific modules could be enriched, which manifested as enrichment in biologically important pathways, such as plant signalling hormone transduction, plant-pathogen interaction, carbon metabolism, phenylpropanoid biosynthesis, glutathione metabolism, MAPK and other stress-related pathways. Conclusions: This study provides an important resource of genes contributing to disease resistance and will deepen our understanding of the regulation of disease resistance, paving the way for further molecular breeding of sesame. [ABSTRACT FROM AUTHOR]

Key message: CsCSE genes might be involved in the tolerance of cucumber to pathogens. Silencing of the CsCSE5 gene resulted in attenuated resistance of cucumber to Podosphaera xanthii and Corynespora cassiicola. Caffeoyl shikimate esterase (CSE), a key enzyme in the lignin biosynthetic pathway, has recently been characterized to play a key role in defense against pathogenic infection in plants. However, a systematic analysis of the CSE gene family in cucumber (Cucumis sativus) has not yet been conducted. Here, we identified eight CsCSE genes from the cucumber genome via bioinformatic analyses, and these genes were unevenly distributed on chromosomes 1, 3, 4, and 5. Results from multiple sequence alignment indicated that the CsCSE proteins had domains required for CSE activity. Phylogenetic analysis of gene structure and protein motifs revealed the conservation and diversity of the CsCSE gene family. Collinearity analysis showed that CsCSE genes had high homology with CSE genes in wax gourd (Benincasa hispida). Cis-acting element analysis of the promoters suggested that CsCSE genes might play important roles in growth, development, and stress tolerance. Expression pattern analysis indicated that CsCSE5 might be involved in regulating the resistance of cucumber to pathogens. Functional verification data confirmed that CsCSE5 positively regulates the resistance of cucumber to powdery mildew pathogen Podosphaera xanthii and target leaf spot pathogen Corynespora cassiicola. The results of our study provide information that will aid the genetic improvement of resistant cucumber varieties. [ABSTRACT FROM AUTHOR]

Quinone outside inhibitor fungicides (QoIs) are crucial fungicides for controlling plant diseases, but resistance, mainly caused by G143A, has been widely reported with the high and widespread use of QoIs. However, two phenotypes of Corynespora casiicola (RI and RII) with the same G143A showed significantly different resistance to QoIs in our previous study, which did not match the reported mechanisms. Therefore, transcriptome analysis of RI and RII strains after trifloxystrobin treatment was used to explore the new resistance mechanism in this study. The results show that 332 differentially expressed genes (DEGs) were significantly up-regulated and 448 DEGs were significantly down-regulated. The results of GO and KEGG enrichment showed that DEGs were most enriched in ribosomes, while also having enrichment in peroxide, endocytosis, the lysosome, autophagy, and mitophagy. In particular, mitophagy and peroxisome have been reported in medicine as the main mechanisms of reactive oxygen species (ROS) scavenging, while the lysosome and endocytosis are an important organelle and physiological process, respectively, that assist mitophagy. The oxidative stress experiments showed that the oxidative stress resistance of the RII strains was significantly higher than that of the RI strains: specifically, it was more than 1.8-fold higher at a concentration of 0.12% H 2 O 2 . This indicates that there is indeed a significant difference in the scavenging capacity of ROS between the two phenotypic strains. Therefore, we suggest that QoIs' action caused a high production of ROS, and that scavenging mechanisms such as mitophagy and peroxisomes functioned in RII strains to prevent oxidative stress, whereas RI strains were less capable of resisting oxidative stress, resulting in different resistance to QoIs. In this study, it was first revealed that mitophagy and peroxisome mechanisms available for ROS scavenging are involved in the resistance of pathogens to fungicides. [ABSTRACT FROM AUTHOR]

This study checked the severity and incubation period of isolates of Corynepora cassiicola (C.c) in soybean cultivars, as well verified whether the position of leaflets influences the susceptibility of the plant to target spot. The experiment was conducted in randomized block with 8 isolates of C.c and 8 soybean cultivars factorial scheme, with five repetitions each block. The plants were inoculated with suspension from 2x104 conidia mL-1. The number of lesions per leaf and the incubation period (IP) were evaluated. The ISO 4S isolate caused greater number of lesions in plants. BMX Potência RR, BMX Força RR, and NA 5909 RG had the lowest occurrence of lesions, while the cultivar BMX Elite IPRO showed the highest number of lesions. More lesions were detected in the lower leaf compared to the upper leaf of the plants. The longest IP was observed for ISO 4S in both leaflets, while the lowest IP for ISO 1A, 3A and 2A in the lower leaf, and for ISO 11S and 1S in the median leaf. For cultivars, significant difference in IP was observed only in the lower leaf, with the longest and shortest IP detected for BMX Elite IPRO and BRS 284, respectively. In general, the upper leaf of the plants presented the shortest IP while the lower leaf had the longest IP. [ABSTRACT FROM AUTHOR]

Corynespora cassiicola (Cc) is a genetically diverse ascomycete found worldwide in tropical and subtropical regions. Cc causes necrotrophic diseases in several plant species, including important crops such as rubber tree, tomato, cotton, and cucumber. Evidence suggests the involvement of one or more Cc host-specific toxins in disease progression. Management of Cc crop diseases is based mainly on pesticide sprays. However, the pathogen’s development of resistance to commonly used fungicides is documented. Resistance breeding is an attractive alternative or supplement to chemical control of Cc crop diseases, but research on this topic is very limited. This review describes the current plant resistance breeding efforts towards Cc resistance and discusses the potential influence of host-specific toxins (HSTs) on such efforts. Although some reports of host resistance exist in a few crops, resistant germplasm and knowledge about resistance mechanisms are limited. Some studies have suggested the involvement of HSTs in disease development, including the upregulation of resistance-related proteins in susceptible reactions and the recessive nature of resistance. In light of this, host resistance may not be achieved through commonly used dominant R-genes.

Target spot caused by Corynespora cassiicola is a problematic disease in tropical and subtropical soybean (Glycine max) growing regions. Although resistant soybean genotypes have been identified, the genetic mechanisms underlying target spot resistance has not yet been studied. To address this knowledge gap, this is the first genome-wide association study (GWAS) conducted using the SoySNP50K array on a panel of 246 soybean accessions, aiming to unravel the genetic architecture of resistance. The results revealed significant associations of 14 and 33 loci with resistance to LIM01 and SSTA C. cassiicola isolates, respectively, with six loci demonstrating consistent associations across both isolates. To identify potential candidate genes within GWAS-identified loci, dynamic transcriptome profiling was conducted through RNA-Seq analysis. The analysis involved comparing gene expression patterns between resistant and susceptible genotypes, utilizing leaf tissue collected at different time points after inoculation. Integrating results of GWAS and RNA-Seq analyses identified 238 differentially expressed genes within a 200 kb region encompassing significant quantitative trait loci (QTLs) for disease severity ratings. These genes were involved in defense response to pathogen, innate immune response, chitinase activity, histone H3-K9 methylation, salicylic acid mediated signaling pathway, kinase activity, and biosynthesis of flavonoid, jasmonic acid, phenylpropanoid, and wax. In addition, when combining results from this study with previous GWAS research, 11 colocalized regions associated with disease resistance were identified for biotic and abiotic stress. This finding provides valuable insight into the genetic resources that can be harnessed for future breeding programs aiming to enhance soybean resistance against target spot and other diseases simultaneously. [ABSTRACT FROM AUTHOR]

Kiwifruit brown spot caused by Corynespora cassiicola is the most significant fungal disease in Sichuan, resulting in premature defoliation, which had a significant impact on yield and fruit quality. The objective of the study was to determine the occurrence regularity and suitability of kiwifruit brown spot in Sichuan. The occurrence of the disease in the main producing region was continuously monitored, the maximum entropy (MaxEnt) model was used to predict its potential distribution, and the key environmental variables were identified using the jackknife method. The results indicated that kiwifruit brown spot was widely distributed across the entire producing region in Sichuan, predominantly affecting the variety "Hongyang". The incidence (p < 0.01) and disease index (p < 0.05) showed a significant positive correlation with the cultivar, and decreased with the altitude increasing. The average area under the ROC curve (AUC) of 10 replicates was 0.933 ± 0.012, with an accuracy of 84.44% in a field test, confirming the reliability of the predicted results. The highly suitable distribution areas of kiwifruit brown spot were mainly located in the Chengdu and Ya'an regions. The entire Panzhihua region was an unsuitable distribution area, and the entire Pujiang County and Mingshan District were highly suitable distribution areas. The key environmental variables affecting the potential distribution of kiwifruit brown spot included isothermality (24.3–33.7%), minimum temperature in August (16.3–23.6 °C), maximum temperature in July (25.5–31.2 °C), minimum temperature in June (15.6–20.9 °C), precipitation in August (158–430 mm), and average temperature in October (15.6–18.8 °C). This study provides a theoretical basis for the reasonable layout of the cultivar and the precise prevention and control of the disease. [ABSTRACT FROM AUTHOR]

Brazilian soybean is mainly grown in the Cerrado, the South American Savannah. We report epidemiological studies of soybean target spot (STS), caused by Corynespora cassiicola in two Cerrado regions in the Federal District (DF) and the state of Bahia (BA), relating the environmental parameters with disease intensities. Here we: i) characterize the field response of soybean cultivars to STS and compute their respective latent periods; ii) relate STS severity to yield; and iii) verify the cross-reaction of C. cassiicola isolates of soybean and cotton to each of these hosts. Ten commercial soybean cultivars were cultivated in DF and BA fields. Additionally, the cv. reactions were studied in greenhouse assays in the spring/summer and autumn/winter seasons. Precipitation and relative humidity were higher in DF than in BA, whereas the temperature was cooler with fewer extremely hot days. Greater STS intensity was observed in DF, reaching 48% incidence and 19% severity. Fungicide applications reduced disease only in the DF trial. Cultivars were separated into four groups: highly susceptible, susceptible, moderately resistant, and resistant. Higher disease severities were recorded in the spring/summer than in the autumn/winter. Length of latent periods correlated with the cv. response to STS and climate conditions. Environmental differences were the probable causes for the lower disease levels recorded in the BA fields and in the autumn/winter trial. A negative relationship was established between severity and yield. In the cross-inoculation studies, isolates of soybean and cotton were able to infect both hosts, but aggressiveness correlated with the host of origin. [ABSTRACT FROM AUTHOR]

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Objective: The aim of this study is to identify the pathogen causing ocular infection in a Chinese patient and to describe its morphological characteristics. Methods: Samples from the patient’s intraoperative pus were collected for microscopic examination and culture. Morphology and drug sensitivities of the isolated fungus were analyzed. Ribosomal DNA (rDNA) sequencing was performed and blasted in GenBank. Results: A strain of fungi was repeatedly isolated from pus samples in different types of medium. No conidia were shown when the isolate cultured on normal PDA medium, whereas pseudoseptate thick-walled conidia were shown when cultured on medium containing leaf leachate. The results of BLAST and phylogenetic trees based on internal transcribed spacer, beta-tubulin, translation elongation factor 1-alpha, and RNA polymerase II gene demonstrated that the isolated fungus was Corynespora cassiicola. Minimum inhibitory concentration results of this organism were as follows: anidulafungin, 0.06 mg/ml; amphotericin B, 0.12 mg/ml; micafungin, 0.06 mg/ml; caspofungin, 0.5 mg/ml; 5-fluorocytosine, >64 mg/ml; posaconazole, 2 mg/ml; voriconazole, 0.25 mg/ml; itraconazole, 0.5 mg/ml; fluconazole, 64 mg/ml. Conclusion: The case was infected with Corynespora cassiicola and led to eye suppurative endophthalmitis and blindness. Combined applications of morphological and molecular biology techniques facilitate accurate diagnosis of fungal infections. [ABSTRACT FROM AUTHOR]

Target spot is caused by Corynespora cassiicola, which heavily affects soybean production areas that are hot and humid. Resistant soybean genotypes have been identified; however, the molecular mechanisms governing resistance to infection are unknown. Comparative transcriptomic profiling using two known resistant genotypes and two susceptible genotypes was performed under infected and control conditions to understand the regulatory network operating between soybean and C. cassiicola. RNA-Seq analysis identified a total of 2571 differentially expressed genes (DEGs) which were shared by all four genotypes. These DEGs are related to secondary metabolites, immune response, defense response, phenylpropanoid, and flavonoid/isoflavonoid pathways in all four genotypes after C. cassiicola infection. In the two resistant genotypes, additional upregulated DEGs were identified affiliated with the defense network: flavonoids, jasmonic acid, salicylic acid, and brassinosteroids. Further analysis led to the identification of differentially expressed transcription factors, immune receptors, and defense genes with a leucine-rich repeat domain, dirigent proteins, and cysteine (C)-rich receptor-like kinases. These results will provide insight into molecular mechanisms of soybean resistance to C. cassiicola infection and valuable resources to potentially pyramid quantitative resistance loci for improving soybean germplasm. [ABSTRACT FROM AUTHOR]

Barbados cherry is cultivated in all Brazilian states. The expansion of barbados cherry requires new techniques and management, especialy technologies that involve cultural treatments. Besides of losses of fruits in harvest, because of plant architecture, the target spot (Corynespora cassiicola), main leaf disease occurred in barbados cherry in the region of Junqueirópolis, SP, causing severe defoliates of plants, damaging of photoassimilates accumulation. Therefore, pruning is an interesting option in culture, because reduce the size of plant, as well as allow light entrance, facilitating the harvest and the control of diseases and/or pest. The present work aimed to evaluate the effect of prunig in the control of target spot and production of barbados cherry. Evaluated four pruning systems in barbados cherry cv. Olivier, with three years of age, cultivated without irrigation, in Junqueirópolis, SP. The pruning increased the amount of flowers, especially in horizontal branches, and reduced canopy volume was verified. The incidence of target spot was higher under conditions of high temperature and humidity. Conditions of low temperature and humidity favored the intensity of defoliation. [ABSTRACT FROM AUTHOR]

Ligustrum quihoui is a perennial shrub that has been cultivated in China as a landscape plant. In November 2020, leaf spots on L. quihoui were observed in several residential areas in the east of Anqing city. Symptoms first appeared as small dark brown dots on the leaf surface which then became larger, forming necrotic lesions and resulting in intense defoliation. To identify the pathogen, infected leaves were collected and cultured on potato dextrose agar (PDA). Three cultures were isolated from the diseased leaves, which grew to form olive green colonies after 5 days of incubation on PDA. Based on colony characteristics, morphology phylogenetic analysis of ribosome transcriptional spacers (rDNA-ITS), and pathogenicity tests, the causal agent of leaf spot on L. quihoui was identified as Corynespora cassiicola. This is the first report to show that C. cassiicola can cause leaf spot on L. quihoui. [ABSTRACT FROM AUTHOR]

In order to effectively control the tobacco Corynespora leaf spot, the biocontrol strain YC2140 screened in the previous work of our laboratory was identified by Biolog automatic microbialidentification systemlog automatic microbial identification system 16S rRNA and gyrB sequence molecular identification. Five fungicides commonly used in production and YC2140 were selected for pot and field control experiments. Results showed that the YC2140 strain was identified as Pseudomonas fluorescens by molecular method and Biolog identification system. The pot experiment results showed that under the recommended dosage (449.78 mL/hm² or 449.78 g/hm2 ), the control efficacy on Corynespora leaf spot from high to low was fluazinam 500 g/L SC (the control efficacy was 78.77%), prochloraz 450 g/L EW (77.85%), tebuconazole 430 g/L SC (67.12%), 1 × 108 cfu/mL YC2140 fermentation broth (61.64%) and boscalid 50% WG (46.12%). The field trial results under the same dosage showed that the control efficacy from high to low was prochloraz 450 g/L EW (43.33%), fluazinam 500 g/L SC (40.97%), tebuconazole 430 g/L SC (27.94%), 1 × 108 cfu/mL YC2140 fermentation broth (26.15%), 70% mancozeb WP (dosage 2998.50 g/hm², control efficacy 21.99%). The results of this study can provide reference for the screening of fungicides for the control of tobacco Corynespora leaf spot disease. [ABSTRACT FROM AUTHOR]

Target spot is an important disease in cucumber culture. Due to differences in the susceptibility of cucumber cultivars to the disease, the objective was to evaluate the behavior of three cvs. in terms of leaf trichome density and biochemical variables in the interaction with the pathogen Corynespora cassiicola. The density of trichomes was evaluated on both sides of the leaves. The activity of peroxidase and polyphenol oxidase enzymes and the levels of free and bound phenolic compounds were evaluated one, three and five days after inoculation or not with the pathogen. Disease severities in Safira, Taiko and Soldier cucumber cvs. reached 0.9%, 2.1% and 4.7%, respectively. Higher density of trichomes was found in the Safira cv., with no differences between Soldier and Taiko cvs. The adaxial side of the leaves had a greater number of trichomes than the abaxial side. The enzymatic activity was higher in the Safira cv., less susceptible to the disease, in relation to the Taiko and Soldier cvs. Inoculated plants showed higher peroxidase activity, demonstrating that the response to infection was accompanied by the synthesis of this enzyme, and it increased with the days after inoculation. The levels of phenolic compounds varied according to the cvs. and as a function of time, with the highest levels in the Safira and Soldier cvs. No direct relationships were observed between biochemical and trichome variables and disease severity in cucumber cvs., since the Soldier cv., the most susceptible to the disease, did not differ in relation to 'Taiko' in enzymatic activities, free phenolic compounds and number of trichomes, including higher levels of bound phenolic compounds. [ABSTRACT FROM AUTHOR]

Plant debris are habitats favoring survival and multiplication of various microbial species. During continuing mycological surveys of saprobic microfungi from plant debris in Yunnan Province, China, several Corynespora-like and Dendryphiopsis-like isolates were collected from dead branches of unidentified perennial dicotyledonous plants. Four barcodes, i.e., ITS, LSU, SSU and tef1-α, were amplified and sequenced. Morphological studies and multigene phylogenetic analyses by maximum likelihood and Bayesian inference revealed three new Corynespora species (C. mengsongensis sp. nov., C. nabanheensis sp. nov. and C. yunnanensis sp. nov.) and a new Kirschsteiniothelia species (K. nabanheensis sp. nov.) within Dothideomycetes, Ascomycota. A list of identified and accepted species of Corynespora with major morphological features, host information and locality was compiled. This work improves the knowledge of species diversity of Corynespora and Kirschsteiniothelia in Yunnan Province, China. [ABSTRACT FROM AUTHOR]

Corynespora cassiicola is a pathogen that causes lesions in different organs of tomato crops. For its control, synthetic fungicides are used that require more than one application. Trichoderma spp. is a highly interactive saprophytic fungus in the rhizosphere known as a biological control agent against plant diseases and promoter of plant growth due to its different modes of action. The effect on physiological and growth variables in Solanum lycopersicum plants inoculated with spore concentrations 1x100, 1x105, 1x106, 1x107 and 1x108 of Trichoderma asperellum Ta-13-17 and Fithan®, (as a commercial control) was evaluated. As a biocontrol agent for C. cassiicola under protected conditions. The 1x106, 1x108 and Fithan® treatments obtained the highest photosynthetic rates with 20.7, 20.6 and 19.6 µmol m-2 s-1 respectively. The 1x108 conidia mL-1 treatment obtained the highest means in the photosynthesis variables 20.6 µmol m-2 s-1, yield 1347.02 g per plant and presented a lower percentage of final severity, lower speed in the distribution of the disease and lower accumulation of area under the disease progress curve. [ABSTRACT FROM AUTHOR]

Grain legume production is of great importance in the world economy, with soybeans being a major agricultural product. Among the main causes of crop losses are diseases caused by pathogens that infect seeds, such as Colletotrichum truncatum, Corynespora cassiicola, Sclerotinia sclerotiorum and Rhizoctonia solani. The fungicides used are not fully effective in controlling these diseases, and new control options are necessary. Photodynamic inactivation (PDI) may be an alternative. PDI consists of the association of a photosensitizer (PS), light and molecular oxygen aimed at the destruction of microbial cells. Porphyrins and their derivatives are aromatic tetrapyrrolic macrocyclic compounds with photosensitizing capacity. The aim of the present study was to evaluate the efficiency of PDI in the photoinactivation of C. truncatum, C. cassiicola, S. sclerotiorum and R. solani, using a mixture of cationic meso‐tetra‐aryl porphyrins as PS, being the first study to consider this formulation as PS in the photoinactivation of these pathogens. Assays were carried out with soybean seeds artificially inoculated with the different fungi, treated with the PS at 10, 50, 100 and 200 μg/ml and submitted to light under an irradiance of 50 mW/cm2. The assays were set up following the blotter test methodology. The evaluations showed significant reductions in the infection rates of the seeds in relation to the controls. The greatest reductions were 46% for C. truncatum, 95.5% for S. sclerotiorum, 87% for C. cassiicola and 92% for R. solani. The results suggest that PDI can be an important alternative to current control methods against these pathogens. [ABSTRACT FROM AUTHOR]

Emerging fungal pathogens could bring irreversible damage to economically important plant species resulting in yield losses. One method of control of plant diseases is crop rotation, whereby the main cultivated crop is rotated with other crops. However, for crop rotation to be successful, the alternative crop must be a non‐susceptible or non‐host plant of the pathogen. In January 2021, for the first time, Corynespora cassiicola was reported to cause leaf spots and fruit rot in eggplant (Solanum melongena) in the Philippines. This study investigated the potential host range of newly reported C. cassiicola in controlled, repeated pathogenicity assays. Of the 36 plant species (19 plant families) assayed for leaf infection, 26 and 23 plant species were pathogenic to C. cassiicola in wounded and unwounded conditions, respectively. Of the 27 plant species (13 plant families) assayed for fruit/head/bulb/tuber infection, 16 and 6 were susceptible to C. cassiicola in wounded and unwounded conditions, respectively. Among all plant species assayed, mango, tomato, and beans were considered very susceptible as infection occurred in both leaves and fruits and wounded and unwounded treatments. The related species, tomato and pepper, were also susceptible to diseases caused by C. cassiicola. This is the first report of the pathogenicity of the C. cassiicola Philippine strain to various plant species assessed in controlled conditions. [ABSTRACT FROM AUTHOR]

Effectors are secreted by plant-associated microorganisms to modify the host cell physiology. As effectors, the Necrosis- and Ethylene-inducing peptide 1-like proteins (NLPs) are involded in the early phases of plant infection and may trigger host immune responses. Corynespora cassiicola is a polyphagous plant pathogen that causes target spot on many agriculturally important crops. Using genome assembly, gene prediction, and proteome annotation tools, we retrieved 135 NLP-encoding genes from proteomes of 44 isolates. We explored the evolutionary history of NLPs using Bayesian phylogeny, gene genealogies, and selection analyses. We accessed the expression profiles of the NLP genes during the early phase of C. cassiicola–soybean interaction. Three NLP putative-effector genes (Cc_NLP1.1, Cc_NLP1.2A, and Cc_NLP1.2B) were maintained in the genomes of all isolates tested. An NLP putative-non-effector gene (Cc_NLP1.3) was found in three isolates that had been originally obtained from soybean. Putative-effector NLPs were under different selective constraints: Cc_NLP1.1 was under stronger selective pressure, while Cc_NLP1.2A was under a more relaxed constraint. Meanwhile, Cc_NLP1.2B likely evolved under either positive or balancing selection. Despite highly divergent, the putative-effector NLPs maintain conserved the residues necessary to trigger plant immune responses, suggesting they are potentially functional. Only the Cc_NLP1.1 putative-effector gene was significantly expressed at the early hours of soybean colonization, while Cc_NLP1.2A and Cc_NLP1.2B showed much lower levels of gene expression. [ABSTRACT FROM AUTHOR]

The secondary metabolites of the phytopathogenic fungus Corynespora cassiicola CC01 from Hevea brasiliensis were investigated. As a result, two new compounds, 5-acetyl-7-hydroxy-6- methoxybenzofuran-2(3H)-one (1) and (S)-2-(2,3-dihydrofuro [3,2-c]pyridin-2-yl)propan-2-ol (2), together with seven known compounds, 4,6,8-trihydroxy-3,4-dihydronaphthalen-1(2H)-one (3), 3,6,8-trihydroxy-3,4-dihydronaphthalen-1(2H)-one (4), curvulin acid (5), 2-methyl-5-carboxymethyl- 7-hydroxychromone (6), tyrosol (7), p-hydroxybenzoic acid (8) and cerevisterol (9), were isolated from the fermentation extract by comprehensive silica gel, reverse phase silica gel, Sephadex-LH20 column chromatography and high-performance liquid chromatography (HPLC). The structures of these compounds were identified by using high-resolution electrospray mass spectrometry (HRESIMS), nuclear magnetic resonance spectroscopy (NMR), optical rotation, ultraviolet and infrared spectroscopy techniques and a comparison of NMR data with those reported in the literature. Compounds 1 and 2 were new compounds, and compounds 3–9 were discovered from this phytopathogenic fungus for the first time. Compounds 1–9 were tested for phytotoxicity against the fresh tender leaf of Hevea brasiliensis, and the results show that none of them were phytotoxic. Additionally, these compounds were subjected to an antimicrobial assay against three bacteria (E. coli, methicillin-resistant Staphylococcus aureus and Micrococcus luteus), but they showed no activity. [ABSTRACT FROM AUTHOR]

Corynespora cassiicola is an anamorphic pathogenic fungus belonging to the phylum Ascomycota with a broad host range. It causes the Corynespora leaf fall (CLF) disease, in rubber trees for which it badly affects natural rubber production. A small phytotoxic protein named cassiicolin derived from the cassiicolin gene (Cas gene) of the fungus was thought to be inducing the pathogenicity in rubber tree; however, some of the isolates that do not possess cassiicolin gene shows aggressiveness on the host. The present study intends to identify the effect of cassiicolin and other putative effectors involved in CLF disease. Comparative screening of the crude toxin extracted from 30 isolates was carried out for cassiicolin activity and the Cas isoform was determined. The isolate named HV showed maximum aggressiveness and the presence of a Cas gene isoform (Cas2). It was sequenced, assembled, and confirmed for the presence of Cas2 isoform of the Cassiicolin gene. This is the first report of an Indian isolate having a Cas-2 isoform from Hevea brasiliensis. The phylogenetic analysis reveals the similarity of Cas gene from HV to Cas2 gene of CC004 strain of China. The effector proteins present in the isolate (HV) were identified. A total of 1035 effector proteins were predicted, among them 1026 were matched with the DFVF database, and in which 229 are classified as leaf spot-associated virulence factors. The predicted gene and proteins were mostly associated with carbohydrate and amino acid metabolism. Identification of specific effectors involved in the pathogenicity helps to step towards the understanding of C. cassiicola virulence and host–pathogen interaction. The data of this work and its future aspects will furnish the facts behind the interaction between the Hevea and Corynespora. [ABSTRACT FROM AUTHOR]

Plant extracts are a valuable alternative to control pathogens of horticultural crops. In the present study, four species of pathogenic fungi were isolated from leaf spots on Solanum lycopersicum and identified by traditional and molecular techniques as Alternaria alternata ITC24, Corynespora cassiicola ITC23, Curvularia lunata ITC22, and Fusarium equiseti ITC32. When 11 aqueous extracts from eight native plants of the Yucatan Peninsula were tested against the four fungi in vitro, the extract from Croton chichenensis roots was most active, inhibiting mycelial growth (79–100%), sporulation (100%), and conidial germination (71–100%) at 3% (w/v). A logarithmic–diagrammatic scale of the pathosystem C. cassiicola–S. lycopersicum was established and used to assess disease severity on inoculated tomato plants in a greenhouse after treatment with the aqueous extract from C. chichenensis roots at 12% (w/v). After 21 days, the disease severity was 57% lower than on the control without extract applied. This dose of the extract was not phytotoxic to tomato leaves and was compatible with the beneficial organisms Bacillus subtilis CBCK47 and Trichodema asperellum Ta13-17. The antifungal efficacy of C. chichenensis is highly promising for incorporation into integrated disease management of tomato crops. [ABSTRACT FROM AUTHOR]

Typical necrotic spots with characteristic target spot symptoms appeared in leaves and stems three days after inoculation and plants collapsed within two-three days after symptom development, but no such symptoms developed in non-inoculated plants during the 14 days the plants were monitored post-inoculation (Figure 3). Keywords: Emerging disease; Nepal; Vegetable disease EN Emerging disease Nepal Vegetable disease 1 3 3 09/28/23 20230701 NES 230701 Tomato ( I Solanum lycopersicum i ) is one of the most important vegetable crops in Nepal and is grown in high tunnels and open fields (Rawal et al., [4]). [Extracted from the article]

The tomato target spot caused by Corynespora cassiicola may have an important economic impact on tomato production in tropical regions. The objective of this work was to study the effect of different colored plastic films on tomato target spot severity, gas-exchange, and fruit yield. Disease severity, photosynthetic rate, stomatal conductance, transpiration rate, relative chlorophyll content and fruit yield were evaluated in tomato, grown in individual minigreenhouses covered with transparent plastic films of different colors (clear, red, blue, green, and yellow). At the beginning of the target spot epidemic, the plants under red and blue covers had lower leaf disease infection than those under other colored films (p = 0.013). However, as the disease progressed over time, the effect of the colored films on disease severity become non-significant (p = 0.82), and at the end of the experimental period, the target spot infection was about 70% in all treatments. Photosynthetic rates, stomatal conductance, and transpiration rate were not affected by the plastic film covers; neither the fruit number or fruit production. This study showed that colored films may reduce the infection by target spot, but only in the early stages of disease development (up to -2% severity). [ABSTRACT FROM AUTHOR]

Corynespora leaf spot caused by Con'nespora cassiicola is an important foliar disease in cucumber. Succinate dehydrogenase inhibitors are the main fungicides used to control this disease. With the application of succinate dehydrogenase inhibitors (SDHIs) in the field. boscalid-resistant isolates have been continuously detected in the field. Resistance monitoring programs were performed to investigate the frequency ancl genotypes of resisbenzimidtant isolates. In our resistance monitoring. the frequency of resistant isolates accountrapidly increased from 9,68 to 85.88% in 2005 to 2020, Nine genotypes conferring SDHI resistance were found in resistant isolates, with different levels of iesistance to SDHIs: B-H278R, B-H278L, B-H278Y. B-I28OV. C-N75S, C-S73P. D-D95E. D-H 105R, and D-0109V. The first .sdh mutation was detected in Hebei Province in China, conferring an amino acid substitution at codon 278 in the sdhB subunit froin histidine to tyrosine (B-H278Y). and it was the dominant resistance genotype in 2014 to 2015. Subsequently, other genotypes were gradually detected iii the field. and the dommant mutations varied across years and across regions. The newest genotype (B-H278L) confening SDHI resistance was found in 2020. To the best of our knowledge. this is the first report of C. cassilcola in cucumber. To date, multiple resistance to SDHIs. quinone outside inhibitors. benzimidtant azole ftingicides, and dicarboximide fungickles have been detected. accountrapidly ing for 75.64% of SDHI-resistant isolates. Therefore, the above four jungicides must be strictly restricted, and further monitoring work in other provinces with mot·e iAolates should be performed in the future. [ABSTRACT FROM AUTHOR]

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Diseases are important limiting factors in profitable eggplant production. Identifying correctly the causative agent of disease and reporting new emerging pathogens are critical steps in a successful disease management program. The study was conducted to identify the causative agents of a leaf spot and fruit rot in eggplant using combined morphological, cultural, pathogenicity and molecular approaches. Three fungal isolates were obtained from diseased leaf and fruit samples. All three isolates were pathogenic to detached fruits and leaves and on leaves of potted plants at seven days post-inoculation. The same fungi were re-isolated from the inoculated leaves and fruits and thus, establishing Koch's postulates. The DNA sequence of the partial sequence of the internal transcribed spacer regions of the three isolates showed 100% similarity to Corynespora cassiicola. This is the first record of C. cassiicola as an eggplant leafspot pathogen in the Philippines and a new record for the fungus as a fruit rot pathogen. With limited knowledge available, fruit rot caused by C. cassiicola may negatively affect potential fruit yield in the field and the quality of marketable fruits. Screening for disease resistance would be worthwhile. [ABSTRACT FROM AUTHOR]

[ Objective] The present paper aimed to identify the causal agents of Camptotheca acuminata leaf spot, and to test the inhibitory activity of different fungicides against the pathogen, so as to provide scientific evidence for the prevention and treatment of the leaf spot disease of C. acuminata. [ Method] The pathogen of the C. acuminata leaf spot was isolated by conventional tissue isolation method and subjected to pathogenicity test. Combining the morphology observation and rDNA-ITS sequence analysis, the pathogen was identified and the toxicity of 12 fungicides to the pathogen was determined by mycelial growth rate method.[ Result] A fungus was isolated from C. acuminata leaf spot in the Chinese Herb Garden of Guangxi Agricultural Vocational University, and the strain was named as XS-1. After pathogenicity test, morphological observation and molecular identification, it was confirmed that Corynespora cassiicola was the causal agent of the C. acuminate leaf spot, which is reported for the first time in China, and the disease was named as Corynespora leaf spot disease. The results of the inhibitory activity test showed that the selected 12 fungicides had a certain inhibitory effect on the growth of strain XS-1 mycelium. Among them, 20% difenoconazole and prochloraz ME had the strongest inhibitory effect with EC50 of 0.098 mg/L, followed by 20% penconazole EW, 50% carbendazim WP, 20% imazalil EW, 250 g/L propiconazole EC, 10% difenoconazole WG with EC50 of 0.3737, 0.4557, 0.4878, 0.5746 and 0.5956 mg/L, respectively.[ Conclusion] Based on pathogenicity test, morphology observation and rDNA-ITS sequence analysis, the pathogen causing C. acuminata leaf spot is identified as C. cassiicola. 20% difenoconazole and prochloraz ME, 20% penconazole EW, 50% carbendazim WP, 20% imazalil EW, 250 g/L propiconazole EC and 10% difenoconazole WG have strong inhibitory effect on the growth of strain XS-1 mycelium, and can be used as an important reference for the control of Corynespora leaf spot on C. acuminata in the field. [ABSTRACT FROM AUTHOR]

Corynespora cassiicola is an important phytopathogenic fungus that severely impairs crop production. Here, we report the molecular characterization of a novel positive-sense single-stranded RNA (+ssRNA) mycovirus, Corynespora cassiicola fusarivirus 1 (CcFV1), isolated from C. cassiicola strain 20200826-3-1. Excluding the poly(A) tail, the genome of the virus is 6491 nt in length and contains three putative open reading frames (ORFs). The large ORF1 encodes a polypeptide of 1524 aa with a conserved RNA-dependent RNA polymerase (RdRp) domain and a helicase (Hel) domain. BLASTp analysis showed that CcFV1 ORF1 has the highest similarity to Setosphaeria turcica fusarivirus 1 (StFV1, 50.45% identity, E-value 0.0). ORF2 encodes a polypeptide with a conserved chromosome segregation ATPase (Smc) domain. The smaller ORF3 encodes a polypeptide with an unknown function. Phylogenetic analysis based on the ORF1- encoded polypeptide showed that CcFV1 is phylogenetically related to members of the newly proposed family "Fusariviridae". Thus, we suggest that CcFV1 might be a novel member of the family "Fusariviridae", and is the first to be discovered in C. cassiicola. [ABSTRACT FROM AUTHOR]

A novel victorivirus was detected in an isolate of Corynespora cassiicola strain 20180909-03 and was named "Corynespora cassiicola victorivirus 1" (CcVV1). The complete genome sequence of this virus is 5140 bp in length and contains 57% GC with two large open reading frames (ORFs) overlapping at the tetranucleotide AUGA. The ORFs were predicted to encode a coat protein (CP) and an RNA-dependent RNA polymerase (RdRp), respectively, which are conserved in dsRNA fungal viruses of the family Totiviridae. Comparison and phylogenetic analysis of the deduced amino acid sequences of RdRp and CP showed that CcVV1 is a new member of the genus Victorivirus. This is the first report of a genomic sequence of a victorivirus infecting Corynespora cassiicola. [ABSTRACT FROM AUTHOR]

Soybean target spot, caused by the fungus Corynespora cassiicola, is an important disease in northwestern Argentina (NWA). A cultural, morphological, and virulence characterization of 24 C. cassiicola isolates from different geographic localities in NWA was performed. The isolates were classified into five different cultural phenotypes, one of which has not been previously described. The ribosomal DNA internal transcribed spacer region sequence from five representative isolates (587 bp) exhibited 100% identity with C. cassiicola. A high variability of conidial morphology was observed among isolates, but no correlation with cultural phenotype was observed. When the soybean cultivar A 8000 RG was challenged with the 24 isolates, different degrees of virulence were observed, ranging from highly virulent to nonvirulent. No association of virulence with cultural or morphological characters was observed, but a relationship with geographical origin was demonstrated. Histopathological studies were performed on a nonvirulent and a highly virulent isolate. Microscopic observations of infected tissues of the former showed low mycelium development restricted to the upper epidermis, a thickening of the cuticle and primary wall of subepidermal cells, and accumulation of callose in phloematic vessels. In tissue infected with the latter, there was abundant mycelium development accompanied by cellular disorganization in mesophyll cells. Pathological challenges of isolates on nine different cultivars indicated that the degree of virulence of isolates depends on the plant genotype, demonstrating that the C. cassiicola–soybean interaction is highly specific. Understanding the genetic basis of this interaction will provide new information for better disease management and breeding strategies. [ABSTRACT FROM AUTHOR]

Babchi (Psoralea corylifolia) is an anciently known medicinal plant commonly found in sub-tropical and temperate parts of India and China. In January 2023, typical target spot symptoms were observed on the leaves of babchi plants in ornamental gardens at GKVK, Bangalore, India. The distinctive spots were extensively present on the foliage viz., leaves, petiole and stem but prominently in older leaves. Pathogenic isolation, purification and morphological characterisation revealed the associated pathogen belongs to the genus Corynespora. Multilocus sequencing and phylogenetic analysis of internal transcribed spacer (ITS) region, actin (ACT) and calmodulin (Cal) regions confirmed Corynespora cassiicola as the causal organism responsible for target leafspot in babchi. Further, pathogenicity was established by proving Koch's postulates. To the best of our knowledge, this is the first report of C. cassiicola causing target leaf spot on babchi plant in India. • Corynespora cassiicola , an emerging pathogen was identified on leaves of babchi (Psoralea corylifolia) causing target leafspot at medicinal gardens, Bangalore, India. • Preliminary microscopic examination followed by isolation and purification accompanied with morphological characterisation revealed that the associated pathogen belongs to the genus Corynespora. • Concatenated multi-gene (ITS, Actin and calmodulin genes) evolutionary analysis confirmed the causal organism as Corynespora cassiicola. • This study signifies the first documentation of C. cassiicola associated with target leafspot of babchi under Indian conditions. [ABSTRACT FROM AUTHOR]

In the tobacco phyllosphere, some of the microbes may have detrimental effects on plant health, while many may be neutral or even beneficial. Some cannot be cultivated, so culture-independent methods are needed to explore microbial diversity. In this study, both metagenetic analysis and traditional culture-dependent methods were used on asymptomatic healthy leaves and symptomatic diseased leaves of tobacco plants. In the culture-independent analysis, asymptomatic leaves had higher microbial diversity and richness than symptomatic leaves. Both asymptomatic and symptomatic leaves contained several potentially pathogenic bacterial and fungal genera. The putative bacterial pathogens, such as species of Pseudomonas , Pantoea , or Ralstonia , and putative fungal pathogens, such as species of Phoma , Cladosporium , Alternaria , Fusarium , Corynespora , and Epicoccum , had a higher relative abundance in symptomatic leaves than asymptomatic leaves. FUNGuild analysis indicated that the foliar fungal community also included endophytes, saprotrophs, epiphytes, parasites, and endosymbionts. PICRUSt analysis showed that the dominant functions of the bacterial community in a symptomatic leaf were cellular processes and environmental information processing. In the other five foliar samples, the dominant functions of the bacterial community were genetic information processing, metabolism, and organismal systems. In the traditional culture-dependent method, 47 fungal strains were isolated from 60 symptomatic tobacco leaf fragments bearing leaf spots. Among them, 21 strains of Colletotrichum (29%), Xylariaceae (14%), Corynespora (14%), Pestalotiopsis (10%), Alternaria (10%), Epicoccum (10%), Byssosphaeria (5%), Phoma (5%), and Diaporthe (5%) all fulfilled Koch's postulates and were found to cause disease on detached tobacco leaves in artificial inoculation tests. Symptoms on detached leaves caused by three strains of Corynespora cassiicola in artificial inoculation tests were similar to the original disease symptoms in the tobacco field. This study showed that the combined application of culture-dependent and independent methods could give comprehensive insights into microbial composition that each method alone did not reveal. [ABSTRACT FROM AUTHOR]

To minimize losses likely to occur due to Corynespora leaf spot, systemic and contact fungicides and formulation of bacterial antagonists like Bacillus subtilis DTBS-5, B. amyloliquefaciens DSBA-11, and Pseudomonas fluorescens DTPF-3 talc-based formulations were evaluated to manage the disease. Though mancozeb has the lowest EC50 value of 1250.54 ppm it was not efficient in the field experiment. In addition, dual culture assay to determine the efficacy of bacterial antagonists against C. cassiicola, B. amyloliquefaciens DSBA-11 effectiovely reduced growth of C. cassiicola. In the field experiments conducted during Kharif 2019 and 2020, two sprays with Azoxystrobin 23 SC@ 0.5 ml lit−1 were found most effective in reducing disease severity by 57.7% and 67.7% respectively during Kharif 2019 and 2020. Azoxystrobin 23 SC treatment resulted in a maximum increase of 281.5 kg in grain yield followed by Pseudomonas fluorescens DTPF-3 264.7 kg and Bacillus subtilis DTBS-5 248.9 kg yield. [ABSTRACT FROM AUTHOR]

Fungicide sprays on soybean in Brazil have contributed to the selection of less sensitive isolates of Corynespora cassiicola. We collected 59 isolates of C. cassiicola from three Brazilian states and two isolates from Paraguay. We investigated their EC50 to quinone outside inhibitors (QoI) and methyl benzimidazole carbamate (MBC), any cross‐resistance to compounds within QoI and MBC groups, and characterized the polymorphisms in their cytb and β‐tubulin genes. Local associations of polymorphisms identified in each gene were statistically correlated with assays results. In total, 79% and 74% of the isolates were classified as resistant to QoI and MBC fungicides, respectively. There was positive cross‐resistance to active ingredients within QoI and MBC groups. For QoI, all isolates presented heteroplasmy in G143A of cytb gene; the mutations F129L and G137R were not found. For MBC, 63% of isolates possessed E198A and 21% possessed F200Y mutations, associated with reduced control by MBC fungicides. Heteroplasmy was identified in two and one isolates from Brazil with E198A and F200Y mutations, respectively. The resistance factor for isolates with E198A (10.9) was statistically similar to the isolate with F200Y (8.8) mutation. Genic association analysis of the in vitro assays using discriminatory doses proved them to be accurate. Reduced sensitivity of C. cassiicola to QoI and MBC was also identified in isolates from Paraguay and resistance to QoI and MBC was widely present in C. cassiicola isolates from the main soybean‐producing states in Brazil. Thus, integrated management measures should be adopted to manage soybean target spot in these countries. [ABSTRACT FROM AUTHOR]

Summary: Information on the occurrence and pathogenicity of the fungal mycoflora on Jatropha curcas in Nigeria is scarce, and the present study focused on this issue in Southwestern Nigeria. A survey and randomized fungal sample collection were conducted in six Southwestern states (Ekiti, Lagos, Ogun, Ondo, Osun and Oyo) of Nigeria within different Jatropha curcas fields. Observed disease symptoms were recorded and diseased samples were collected for fungal isolation and identification. Pathogenicity tests of the isolated organisms were carried out on 4-week-old J. curcas seedlings using a foliar spray inoculation technique. Data on percentage occurrence of fungal isolates per state were collected and analysed using analysis of variance and mean separation techniques in SAS. Eleven fungal genera were observed to be associated with Jatropha curcas in Southwestern Nigeria. The occurrence of these organisms differed significantly (p ≤ 0.05) per state. Five genera (Curvularia, Colletotrichum, Fusarium, Lasiodiplodia, and Oidium) were confirmed as pathogenic on J. curcas. There were significant differences in fungal occurrence across the states for all the fungal genera except for Colletotrichum spp. It was evident that among the six states, Ekiti, Ondo and Oyo had the highest recorded occurrences of all the fungi isolated from J. curcas with the exception of Corynespora, suggesting that the crop is more susceptible to fungal infections in those three states. [ABSTRACT FROM AUTHOR]

The objective was to carry out a survey of the occurrence of the target spot (Corynespora cassiicola) in cucumber crops in São Paulo State; to evaluate culture media for sporulation of the pathogen and the aggressiveness of isolates of the pathogen in cucumber plants. The target spot was found in nine municipalities, being the main disease in six of the ten municipalities sampled, with leaf incidence above 50%, showing that the target spot of cucumber is widely distributed in São Paulo State. Other diseases found in lower incidences were scab (Cladosporium cucumerinum), alternaria spot (Alternaria cucumerina), cercospora spot (Cercospora citrullina) and downy mildew (Pseudoperonospora cubensis), but also present in most sampled municipalities. The zoned spot (Leandria momordicae) was found in samples from three municipalities and with an incidence lower than 20%. Greater sporulation of the pathogen occurred in tomato juice and oat flour media, without scraping the surface of the colony maintained for 16 days at 25°C, under continuous fluorescent light. The germination of C. cassiicola isolates used in the aggressiveness test was between 82.8 and 95.5%, with the 50 isolates separated into two groups. The isolates were separated into four groups within the range of 3.1 to 22.3% in disease severity, after ten days of inoculation of the pathogen, showing the genetic variability within the species, which should be considered in management studies, such as genetic improvement. [ABSTRACT FROM AUTHOR]

Rubber plantations are known to udergo various biotic and abiotic stresses. However, the symbiotic bacterial endophytes that inhabit them provide protection. Here, we isolated bacterial endophytes from the rubber tree, Hevea brasiliensis (Willd. ex A.Juss.) Müll.Arg. and studied their antagonistic activity against major pathogens such as Phytophthora meadii, Corynespora cassiicola and Corticium salmonicolar. The antifungal metabolites such as HCN, siderophores and salicylic acid were produced by the antagonistic endophytes under in vitro conditions. Bioassay showed the growth promotion by a consortium of selected antagonistic endophytes in H. brasiliensis seedlings. The photosynthetic efficiency of seedlings increased after endophyte inoculation. Endophyte-treated plants showed accumulation of starch granules in root tissues. The selected antagonistic isolates belong to Bacillus sp. and Pseudomonas sp. The study revealed the biocontrol and growth promoting potential of bacterial endophytes from H. brasiliensis. [ABSTRACT FROM AUTHOR]

Summary: Carboxamide fungicides target succinate dehydrogenase (SDH). Recently published monitoring studies have shown that Corynespora cassiicola isolates are resistant to one or several SDH inhibitors (SDHIs) with amino acid substitutions in the SDH B and D subunits. We confirmed, by site‐directed mutagenesis of the sdhB and sdhD genes, that each of the mutations identified in the field strains of C. cassiicola conferred resistance to boscalid and, in some cases, cross‐resistance to other SDHIs (fluopyram, carboxin and penthiopyrad). Analyses of the enzyme activity and sdhB and sdhD gene expression show that modifications (SdhB_H278Y and SdhD_H105R) that result in a decline in SDH enzyme activity may be complemented by gene overexpression. The SdhB_H278Y, SdhB_I280V and SdhD_H105R mutants suffered large fitness penalties based on their biological properties, including conidia production and germination, mycelial growth, pathogenicity or survival abilities under environment stress. However, fitness cost was not found in the SdhB_H278R, SdhD_D95E and SdhD_G109V mutants. In the evaluation of resistance to boscalid in 2018 and 2019, the frequency of the SdhD_D95E and SdhD_G109V genotypes in the Liaoning and Shandong provinces changed dramatically compared with 2005–2017, from low resistance frequency (0.53% for D95E and 2.53% for G109V) to dominant resistance frequency (17.28% for D95E and 15.38% for G109V). Considering both the fitness and increased frequency of these genotypes, we may infer that the SdhD_D95E and SdhD_G109V mutants will be the dominant resistance mutants in field. [ABSTRACT FROM AUTHOR]

The placement of Corynespora olivacea within the large genus Corynespora (Pleosporales) is controversial, because the species is distantly related to other congeners, including the type species C. cassiicola. Corynespora cassiicola is a polyphagous, cosmopolitan plant pathogen. Successful colonization of plant tissues requires the pathogen's effector repertoire to modulate host cell physiology and facilitate the infection process. We sequenced and performed functional annotations on the genomes of C. cassiicola CC_29 (genome size about 44.8 Mb; isolated from soybean leaves) and C. olivacea CBS 114450 (32.3 Mb). Our phylogenomic approach showed that C. cassiicola is distantly related to C. olivacea, which clustered among the Massarinaceae family members, supporting a hypothesis that C. olivacea was originally misclassified. The predicted sizes for the proteome and secretome of C. cassiicola (18,487 and 1327, respectively) were larger than those of C. olivacea (13,501 and 920; respectively). Corynespora cassiicola had a richer repertoire of effector proteins (CAZymes, proteases, lipases, and effectors) and genes associated with secondary metabolism than did C. olivacea. [ABSTRACT FROM AUTHOR]

Target leaf spot (TLS), caused by Corynespora cassiicola , is an emerging and high-incidence disease that has spread rapidly on the global scale. Aerospores released by infected plants play a significant role in the epidemiology of cucumber TLS disease; however, no data exist concerning the infectiousness and particle size of C. cassiicola aerospores, and the experimental evidence for the aerospores transmission was lacking. In the present study, highly effective approaches to collect and quantify aerospores were developed for exposure chamber and greenhouse studies. Quantifiable levels of C. cassiicola aerospores were detected in 27 air samples from nine naturally infested greenhouses, ranging from 198 to 5,969 spores/m3. The C. cassiicola strains isolated from air samples were infective to healthy cucumber plants. Exposure chambers were constructed to study the characteristics of C. cassiicola aerospores released by artificially infested cucumber plants. The particle size of C. cassiicola ranged predominately from 2.1 to 4.7 μm, accounting for 71.97% of the total amount. In addition, the transmission dynamics of C. cassiicola aerospores from donor cucumber plants to recipient cucumber plants were confirmed in exposure chambers and greenhouses. The concentration of C. cassiicola aerospores was positively associated with cucumber TLS disease severity. This study suggested that aerospore dispersal is an important route for the epidemiology of plant fungal disease, and these data will contribute to the development of new strategies for the effective alleviation and control of plant diseases. [ABSTRACT FROM AUTHOR]