Genome size expansions are common among eukaryotic lineages. Enlarged genomes can be bioenergetically demanding, and active mobile elements can trigger chromosomal rearrangements and loss of gene function. What triggers genome size expansions remains largely unexplored in many biological clades, particularly within the fungal kingdom. Activation of large transposable elements (TEs), such as long-terminal repeats (LTRs), is a common contributor. Yet the mechanisms of LTR activation remain poorly understood. Here, we focus on the fungal genus Pseudocercospora and closely related species with known variation in genome size. In using an assembly-free approach, we found that TE content is highly variable among species, with species-specific retrotransposon families being the main drivers of independent genome expansions. We further focused on the two species with the most expanded genomes and reference-quality genomes, P. fijiensis and P. ulei. We found that the P. ulei genome is compartmentalized, with highly variable TE densities among chromosomal regions, and a striking reduction in pathogenicity-associated genes. Overall, our study indicates that species of Pseudocercospora originally had reduced genome sizes, and genome expansions are species-specific, driven by heterogeneous sets of TE families. We discuss what might have caused TE activation and subsequent proliferation in the genus, including stress conditions and host adaptation. Surveys of clades with highly dynamic genome sizes are crucial for the investigation of causal factors driving long-term TE dynamics.Supplementary InformationThe online version contains supplementary material available at 10.1186/s13100-026-00396-x.

Zelkova serrata is a widely planted tree species valued both as a source of lumber and as an important street tree in the urban ecosystems of East Asian countries, including South Korea. In 2023 and 2024, severely infected leaves showing leaf spot symptoms were frequently observed on 35 Z. serrata trees in Daejeon (36°22'09.2"N 127°21'05.1"E and 36°22'19.9"N 127°20'36.2"E), with around 80% of leaves affected within 0.14 and 1.25 ha areas, respectively. Initial symptoms included pale- to dark-brown orbicular or irregular spots, which developed into larger blotches, leading to bleaching and leaf loss (Fig. 1). Stromata were large (35–40 μm), globular, olivaceous brown, and partly superficial or immersed. Conidiophores appeared in dense fascicles, cylindrical, 18–35 × 3.5–4.3 μm, smooth, usually with one septum. Conidia were guttulate, cylindrical to narrowly obclavate, 17–39 × 2.8–4.3 μm, with one to three septa. Fungal isolations were directly made by transferring spores from leaf spots onto 2% malt extract agar (MEA), followed by incubation at 25 ℃. On MEA, colonies were circular, raised, corrugated with smooth, grey. Of those successfully isolated, two representative isolates, CDH063 and CDH064, were selected from each of the two areas and were subjected to the phylogenetic analysis based on a maximum-likelihood. This was achieved based on partial sequences of the internal transcribed spacer (ITS) (Gardes and Bruns 1993; White et al. 1990), actin (Carbone and Kohn 1999; Groenewald et al. 2013), translation elongation factor-1 alpha (TEF-1α) (Nakashima et al. 2016; Carbone and Kohn 1999), and the second largest subunit of RNA polymerase II (rpb2) (Nakashima et al. 2016). The sequence data produced in this study were deposited in GenBank: (ITS: PQ469938–939; actin: PQ496835–836; TEF-1α: PQ496831–832; 40 rpb2: PQ496833–834). The multi-locus phylogenetic analysis revealed that the fungus isolated in this study was positioned in a clearly distinct lineage, provisionally representing an undetermined species of Pseudocercospora, which is most closely related to P. zelkovae MUCC872 (ITS: GU269835, TEF-1α: GU384547, actin: GU320537, rpb2: KX462665) (Nakashima et al. 2016; Groenewald et al. 2024) (Fig. 2). Morphologically, the isolates obtained in this study differed from P. zelkovae in stromata size and conidial septation. In addition, sequence comparisons showed that this pathogen differed from P. zelkovae by 5 of 312 (~1.6%) in the TEF-1α, 1 of 187 (~1.0%) in the actin, and 29 to 671 (~4.3%) in the rpb2 sequences. These multi-locus differences, together with the morphological distinctions, suggest that the isolate represents a genetically distinct lineage. Pathogenicity tests were conducted twice, each using six seedlings of Z. serrata were used. For inoculation, the leaves of each seedling were sprayed with 10 ml of conidial suspension (1 × 106 conidia/ml of the isolate, CDH063), while three seedlings were treated with distilled water as controls. Leaf spot symptoms identical to those observed in the field developed on all inoculated seedlings one week after the inoculation, while no symptoms appeared on the controls. Re-isolations were successfully made from the treatments, thus fulfilling Koch’s postulates. In addition to P. zelkovae that was previously reported as a pathogen causing leaf spot disease on Z. serrata in South Korea (Farr et al. 2024), our work additionally discovered the tree pathogenic fungus on Z. serrata. Given the fact that Z. serrata is the most common street and protected tree in South Korea, providing important ecological and cultural functions in urban areas, the emergency of a new Pseudocercospora lineage causing leaf spot on this tree species is of particular concern to urban ecosystems in the country. Consequently, this indicates that further studies are required to gain a more detailed understanding of the distribution of the diseases and the intraspecies diversity of this species.

The North-Eastern region of Uttar Pradesh, India, boasts a diverse array of biological species, including micro- and macro-fungi. Pseudocercospora Speg. is a plant pathogenic fungus responsible for various diseases in different plants of economic importance. In the current study, while conducting a survey of villages, agricultural fields and woodlands of Gorakhpur district, two plant-pathogenic species of Pseudocercospora have been collected and documented, named - Pseudocercospora solanicola and Pseudocercospora withaniae, causing infection to two plants of medicinal importance of Family – Solanaceae - Solanum nigrum and Withania somnifera. Morpho-taxonomic descriptions of these two Pseudocercospora species have been done, including Camera Lucida drawings and photomicrography. Phyto-pathological studies have also been conducted, with reference to decrease in photosynthesizing regions of leaves. It is determined that these Pseudocercospora species influence the efficacy along with therapeutic qualities of these medicinally important plants.

Several Pseudocercospora species were recognized as leaf spot pathogens on various vitaceous plants worldwide. Of them, Pseudocercospora vitis on Vitis spp. and Ps. ampelopsidis on Ampelopsis glandulosa var. heterophylla were reported to occur in Korea to date. The species diversity of the genus Pseudocercospora associated with vitaceous plants in Korea was revised in the scope of multigene sequence analyses and detailed morphological examinations. This study includes the introduction of new host finding for Ps. vitis, Vitis labrusca × Vitis vinifera “Campbell Early” in Korea, and one new species, Ps. neovitis sp. nov. on Vitis flexuosa. Illustrations of diseased plants with micrographs of pathogens, generated phylogenetic trees, and a discussion, including comparisons with related Pseudocercospora species are presented here.

Pseudocercospora trifoliorum, a newly discovered foliicolous hyphomycetous fungus on Grona triflora (Fabaceae), is taxonomically described and illustrated. Its phylogeny was determined using LSU, RPB2, and ITS regions to analyze evolutionary relationships. The taxon is compared to closely related Pseudocercospora species through morphological traits and molecular analysis, improving insights into its classification and evolutionary relationships.

Species of Pseudocercospora are commonly associated with leaf and fruit spots on diverse plant hosts in sub-tropical and tropical regions. Pseudocercospora spp. have mycosphaerella-like sexual morphs, but represent a distinct genus in Mycosphaerellaceae (Mycosphaerellales, Dothideomycetes). The present study adds a further 29 novel species of Pseudocercospora from 413 host species representing 297 host genera occurring in 60 countries and designates four epitypes and one lectotype for established names. This study recognises 329 species names, with an additional 69 phylogenetic lineages remaining unnamed due to difficulty in being able to unambiguously apply existing names to those lineages. To help elucidate the taxonomy of these species, a phylogenetic tree was generated from multi-locus DNA sequence data of the internal transcribed spacers and intervening 5.8S nuclear nrRNA gene (ITS), partial actin (actA), and partial translation elongation factor 1-alpha (tef1), as well as the partial DNA-directed RNA polymerase II second largest subunit (rpb2) gene sequences. Novel species described in this study include those from various countries as follows: Australia, Ps. acaciicola from leaf spots on Acacia sp., Ps. anopter from leaf spots on Anopterus glandulosus, Ps. asplenii from leaf spots on Asplenium dimorphum, Ps. australiensis from leaf spots on Eucalyptus gunnii, Ps. badjensis from leaf spots on Eucalyptus badjensis, Ps. erythrophloeicola from leaf spots on Erythrophleum chlorostachys, Ps. grevilleae from leaf spots on Grevillea sp., Ps. lophostemonigena from leaf spots on Lophostemon confertus, Ps. lophostemonis from leaf spots on Lophostemon lactifluus, Ps. paramacadamiae from leaf spots on Macadamia integrifolia, Ps. persooniae from leaf spots on Persoonia sp., Ps. pultenaeae from leaf spots on Pultenaea daphnoides, Ps. tristaniopsidis from leaf spots on Tristaniopsis collina, Ps. victoriae from leaf spots on Eucalyptus globoidea. Brazil, Ps. musigena from leaf spots on Musa sp. China, Ps. lonicerae-japonicae from leaf spots on Lonicera japonica, Ps. rubigena leaf spots on Rubus sp. France (Réunion), Ps. wingfieldii from leaf spots on Acacia heterophylla. Malaysia, Ps. musarum from leaf spots on Musa sp. Netherlands, Ps. rhododendri from leaf spots on Rhododendron sp. South Africa, Ps. balanitis from leaf spots on Balanites sp., Ps. dovyalidicola from leaf spots on Dovyalis zeyheri, Ps. encephalarticola from leaf spots on Encephalartos sp. South Korea, Ps. grewiana from leaf spots on Grewia biloba, Ps. parakaki from leaf spots on Diospyros kaki, Ps. pseudocydoniae from leaf spots on Chaenomeles lagenaria, Ps. paracydoniae from leaf spots on Chaenomeles speciosa. Thailand, Ps. acerigena from leaf spots on Acer sp., Ps. tectonigena from leaf spots on Tectona grandis. Epitypes are designated for Cercospora bonjeaneae-rectae, Cercospora halleriae, Ps. eucleae, and an epitype as well as a lectotype for Ps. macadamiae. Results obtained in the present study contribute to a better understanding of the host specificity and distribution in Pseudocercospora spp., many of which represent important pathogens of food or fibre crops, or organisms of quarantine concern. Citation: Groenewald JZ, Chen YY, Zhang Y, Roux J, Shin H-D, Shivas RG, Summerell BA, Braun U, Alfenas AC, Ujat AH, Nakashima C, Crous PW (2024). Species diversity in Pseudocercospora. Fungal Systematics and Evolution 13: 29-89. doi: 10.3114/fuse.2024.13.03.

Cannabis sativa is gaining attention as an agronomically important crop in many countries around the world. The identification and control of leaf diseases in cannabis are very important for cannabis cultivators as leaves are the most economically important part of the cannabis plants. In 2022, several cannabis plants in cultivations showing olive leaf spot symptoms emerged from Chiang Rai province, Thailand. Preliminary studies indicated that the causal organism is Pseudocercospora sp. Species of Pseudocercospora are important plant pathogens that are now identified through morphological studies combined with DNA sequence data of Internal Transcribed Spacer (ITS), Actin (act), Translation Elongation Factor (tef), and RNA Polymerase II second largest subunit (rpb2) gene regions. We aimed to investigate and understand the emergence of olive leaf spot disease in cannabis plants in Chiang Rai province, Thailand, with a specific focus on the combined morpho-molecular identification of the pathogen. In our study, Pseudocercospora cannabina, the causal organism of olive leaf spot disease, was identified as the leaf spot-causing pathogen with both morphological and phylogenetic analyses. Our study is the first to provide molecular data for Ps. cannabina as the typenor Ps. cannabina isolates from previous studies have made molecular data available for this species. A pathogenicity test, re-isolation, and identification steps were performed to fulfill Koch’s postulates. This comprehensive approach enhances our understanding of the olive leaf spot disease and its causative agent in cannabis.

Accurate taxonomic classification of samples from infected host material is essential for disease diagnostics and genome analyses. Despite the importance, diagnosis of fungal pathogens causing banana leaf diseases remains challenging. Foliar diseases of bananas are mainly caused by 3 Pseudocercospora species, of which the most predominant causal agent is Pseudocercospora fijiensis. Here, we sequenced and assembled four fungal isolates obtained from necrotic banana leaves in Bohol (Philippines) and obtained a high-quality genome assembly for one of these isolates. The samples were initially identified as P. fijiensis using PCR diagnostics; however, the assembly size was consistently 30 Mb smaller than expected. Based on the internal transcribed spacer (ITS) sequences, we identified the samples as Zasmidium syzygii (98.7% identity). The high-quality Zasmidium syzygii assembly is 42.5 Mb in size, comprising 16 contigs, of which 11 are most likely complete chromosomes. The genome contains 98.6% of the expected single-copy BUSCO genes and contains 14,789 genes and 10.3% repeats. The 3 short-read assemblies are less continuous but have similar genome sizes (40.4-42.4 Mb) and contain between 96.5 and 98.4% BUSCO genes. All 4 isolates have identical ITS sequences and are distinct from Zasmidium isolates that were previously sampled from banana leaves. We thus report the first continuous genome assembly of a member of the Zasmidium genus, forming an essential resource for further analysis to enhance our understanding of the diversity of pathogenic fungal isolates as well as fungal diversity.

Fungi in Cercospora and Pseudocercospora are commonly known as cercosporoid fungi. In the current study, a cercosporoid fungus was isolated from Mangifera indica from Chiang Mai, Thailand. The isolate was identifi ed as Pseudocercospora mangiferae sp. nov. based on morphology and ITS, act, tef1-α and rpb2 multigene phylogeny. Further, this is the fi rst report of a Pseudocercospora species on M. indica in Thailand.

A new species of Pseudocercospora is discovered causing foliar disease on the medicinal plant Rauvolfia serpentina (Apocynaceae) from India. The new species is described and illustrated on the morphology of asexual-morphs, growth characters and multigene phylogeny. Morphologically, new species has similar characters with allied species in Pseudocercospora but differs in having catenate and branched conidia. Phylogenetic analysis using combined LSU, ITS, ACT and TEF1α data supports the isolate to be a new species of Pseudocercospora (Capnodiales, Mycosphaerellaceae).

A new species Pseudocercospora solanicola is discovered causing severe leaf spot disease on Solanum nigrum from Sonebhadra. Species is described and illustrated based on morphology, molecular sequence analysis and phylogeny of the large subunit (LSU) and internal transcribed spacer region of the nuclear ribosomal RNA (rRNA) gene. Morphologically, new species has similarity with allied species in Pseudocercospora but differs in having black circular, velvety leaf spot and size of stromata, conidia and conidiophores. A key to Pseudocercospora species on Solanum has been provided.

Pseudocercospora fijiensis is the causal agent of the highly destructive black Sigatoka disease of banana. Previous research has focused on polyketide synthase gene clusters in the fungus, given the importance of polyketide pathways in related plant pathogenic fungi. A time course study of expression of the previously identified PKS7-1, PKS8-2, and PKS10-2 gene clusters showed high expression of all three PKS genes and the associated clustered genes in infected banana plants from 2 weeks post-inoculation through 9 weeks. Engineered transformants silenced for PKS8-2 and PKS10-2 were developed and tested for pathogenicity. Inoculation of banana plants with silencing transformants for PKS10-2 showed significant reduction in disease symptoms and severity that correlated with the degree of silencing in the conidia used for inoculation, supporting a critical role for PKS10-2 in disease development. Unlike PKS10-2, a clear role for PKS8-2 could not be determined. Two of four PKS8-2 silencing transformants showed reduced disease development, but disease did not correlate with the degree of PKS8-2 silencing in the transformants. Overall, the degree of silencing obtained for the PKS8-2 transformants was less than that obtained for the PKS10-2 transformants, which may have limited the utility of the silencing strategy to identify a role for PKS8-2 in disease. Orthologous PKS10-2 clusters had previously been identified in the related banana pathogens Pseudocercospora musae and Pseudocercospora eumusae. Genome analysis identified orthologous gene clusters to that of PKS10-2 in the newly sequenced genomes of Pseudocercospora fuligena and Pseudocercospora cruenta, pathogens of tomato and cowpea, respectively. Our results support an important role for the PKS10-2 polyketide pathway in pathogenicity of Pseudocercospora fijiensis, and suggest a possible role for this pathway in disease development by other Pseudocercospora species.

Cryptic diversity, multilocus phylogeny, and pathogenicity of cercosporoid fungi associated with common bean and cowpea

Pseudocercospora haldinae, a new anamorphic foliicolous hyphomycetous fungus discovered on living leaves of Haldina cordifolia (Rubiaceae) is taxonomically described and illustrated. This species is compared with closely related species of Pseudocercospora and other dematiaceous cercosporoid forms reported on the same host genus. The phylogeny of this species has been inferred from partial nuclear ribosomal 28S large subunit (LSU) and complete internal transcribed spacer (ITS) rDNA sequence data. On the basis of LSU, P. haldinae represents characteristic features of Pseudocercospora s. str. and did not form red crystals when cultivated on agar media.

A new species of Pseudocercospora is described causing leaf spot disease on Crotalaria assamica from India. The identity of isolate was based on asexual morphs, cultural characteristics and phylogenetic analyses of partial nuclear ribosomal 28S large subunit and complete internal transcribed spacer rDNA sequence data with high statistical support value. Morphologically this species has characters similar to allied species in genus Pseudocercospora but differs in having catenate and branched conidia. Phylogenetic analysis using LSU and ITS reveals it a new species of >i>Pseudocercospora (Capnodiales, Mycosphaerellaceae).

A cercosporoid fungus associated with leaf lesions of Dypsis lutenscens (Arecaceae) was observed in Chiang Rai, Thailand. This study describes the new species Pseudocercospora dypsidis based on morphological characteristics and phylogenetic analyses from three gene regions, ITS, TEF-1α, and ACT. Single gene analyses are generally insufficient for identification of Pseudocercospora species, or for segregation of other genera in the Pseudocercospora complex. A list is provided of all Pseudocercospora species known from Thailand and the need to confirm their identifications by a polyphasic approach is stressed.

Pseudocercospora hamiltoniani, a new asexual foliicolous hyphomycetous fungus was discovered on living leaves of Euonymus hamiltonianus (Celastraceae) is described and illustrated. This species is compared with closely related species of Pseudocercospora and other cercosporoid forms reported on the same host genus. The phylogeny of this species has been inferred from internal transcribed spacer (ITS). Phylogenetically, Ps. hamiltoniani differ from closely related Ps. ranjita in having smooth to verruculose mycelium; mostly solitary, highly septate, smooth to verruculose, longer and thicker conidiophores and highly septate with oblique septation, presence of rounded cells, smooth to verruculose, longer and thicker conidia.

Chinese mesona (Platostoma palustre) plays an important role as special crop in Southeast Asia and Taiwan for the production of herbal tea, grass jelly, and further processed food. In order to assess the potential threat of fungi to Chinese mesona, we surveyed isolates from symptomless plants in the area of mesona production, as well as from leaf spots of potted plants in a garden shop and a plantation in a botanical garden in Taiwan. From leaves, stems, and roots of 15 symptomless plants sampled at five collection events over two years, 154 isolates from 810 surface-sterilized plant fragments were obtained and identified based on DNA sequence data of the internal transcribed spacer region, and partially of the β-tubulin and histone H3 genes. The most common species belonged to the genera Cercospora, Colletotrichum, and Fusarium and were considered to be potential plant pathogens. Latent pathogenicity was confirmed by an infection experiment with an endophytic strain of Corynespora cassiicola. Observation of leaf spot disease associated with Cercospora kikuchii suggested pathogenicity of this fungus, which was also isolated as an endophyte from symptomless leaves. We hypothesize that the most common endophytic fungi are latent pathogens in the host and may cause plant disease when the host becomes weakened by senescence or changed cultivation condition. Leaf spots of plants in the botanical garden were associated with a species of Pseudocercospora, which was not found among the endophytic isolates and is newly described based on morphology and analysis of translation elongation factor 1 alpha gene sequences.

HomePlant DiseaseVol. 104, No. 12First Report of Leaf Spot Caused by a Provisionally Novel Species of Pseudocercospora on Ligustrum japonicum in South Korea PreviousNext DISEASE NOTES OPENOpen Access licenseFirst Report of Leaf Spot Caused by a Provisionally Novel Species of Pseudocercospora on Ligustrum japonicum in South KoreaDong-Hyeon Lee, Ji Yeon Oh, Byeongkwan Kim, and Sang-Hyun LeeDong-Hyeon Lee†Corresponding author: D.-H. Lee; E-mail Address: Leedh2009@gmail.comhttp://orcid.org/0000-0002-6400-6132Division of Forest Insect Pests and Diseases, National Institute of Forest Science, Seoul, 02455, South Korea, Ji Yeon OhDivision of Forest Insect Pests and Diseases, National Institute of Forest Science, Seoul, 02455, South Korea, Byeongkwan KimDepartment of Plant Medicine, Chungbuk National University, Cheongju 28644, South Korea, and Sang-Hyun LeeDivision of Forest Insect Pests and Diseases, National Institute of Forest Science, Seoul, 02455, South Korea AffiliationsAuthors and Affiliations Dong-Hyeon Lee1 † Ji Yeon Oh1 Byeongkwan Kim2 Sang-Hyun Lee1 1Division of Forest Insect Pests and Diseases, National Institute of Forest Science, Seoul, 02455, South Korea 2Department of Plant Medicine, Chungbuk National University, Cheongju 28644, South Korea Published Online:8 Oct 2020https://doi.org/10.1094/PDIS-05-20-1151-PDNAboutSectionsView articlePDFPDF PlusSupplemental ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat View articleLigustrum japonicum Thunb. (Oleaceae) is a hedge plant along streets in South Korea. In August 2019, leaf spots on trees were observed in Naju in Jeonnam Province (35°00′32.4″N, 126°49′17.6″E). Diseased leaves on each affected tree within a 0.3-ha area were ∼70%. The initial symptoms were orbicular or irregular, pale-brown to dark-brown spots on leaves that were typically 0.5 to 1.3 cm in diameter. When leaves were severely affected, larger blotches were formed, leading to bleaching symptoms and eventually defoliation. Thin narrow or bunched hyphae emerged through the stomata, which were smooth, septate, branched, hyaline or pale brown, and 2 to 3 μm in diameter. The stromata emerging through the cuticle were large, well-developed, globular, olivaceous brown, 35 to 55 µm diameter, and partly superficial or immersed. The conidiophores were aggregated in dense fascicles emerging through stomatal openings and were cylindrical, straight to slightly geniculate, 17 to 53 × 5.5 to 7.5 μm in diameter, and smooth with usually a single septum. Conidia were guttulate cylindrical to narrowly obclavate, straight to mildly curved, obtuse to rounded at the apex, truncate at the base, variable in length, and 17 to 57 × 3 to 4.5 μm in diameter, with one to three septa. Diseased leaves obtained from 15 locations in the area were randomly selected, and fungal isolations were performed by transferring spores from leaf spots on MEA. Among 15 cultures, 10 isolates were retained based on culture characteristics, and two randomly selected monoconidial cultures were deposited in the culture collection (CDH) of the National Institute of Forest Science, Korea (CDH2019-4 and 5). To confirm the identity of the fungus isolated in this study, two isolates, CDH2019-4 and 5, were selected for molecular study, and multiple sequence comparisons were performed based on partial sequences of the ITS, translation elongation factor-1 alpha (TEF-1α), actin, and the second largest subunit of RNA polymerase II (rpb2) using the respective primer pairs ITS1/ITS4, EF1-728F/EF1-986R, ACT-512F/ACT-783R, and RPB2-5f2/fRPB2-7cR (Nakashima et al. 2016). The sequence data were deposited in GenBank: MN453602 and MT484236 (ITS), MN497240 and MT491200 (TEF-1α), MN497241 and MT491201 (actin), and MN497242 and MT491202 (rpb2). The resulting sequences were concatenated as a single dataset and subjected to phylogenetic analysis with the maximum likelihood method. The results showed that the isolated cercosporoid fungus formed a clearly distinct lineage that provisionally represents an undetermined species of Pseudocercospora, which is most closely related to P. cornicola (Tracy & Earle) Y.L. Guo & X.J. Liu, MUCC 909 (GU269283, ITS; GU384400, TEF-1α; GU320389, actin; MG594035, rpb2) (Crous et al. 2013). Sequence comparisons revealed that the sequences of this Korean cercosporoid fungus differed from P. cornicola at 10 of 499 characters (∼2.0%) for ITS, four of 300 (∼1.3%) for TEF-1α, and 42 of 741 (∼5.7%) for rpb2 but were identical for actin. This isolate is morphologically distinct from P. cornicola because it has longer conidiophores and smaller conidia. Pathogenicity was confirmed by performing inoculation trials on five seedlings of L. japonicum. Leaves of each plant were sprayed with 5 ml of conidial suspension (105 conidia/ml, CDH2019-5). Three control plants were sprayed with sterile water. After 3 weeks in the greenhouse at 25°C and in 80% RH, leaf spots appeared, identical to those observed in the field. No symptoms were observed on control plants. Pseudocercospora sp. was reisolated from 90% of lesions, fulfilling Koch's postulates. Leaf spots associated with a Pseudocercospora sp. on L. japonicum have not been recorded elsewhere (Farr and Rossman 2020). This disease poses a serious threat by reducing plant vigor and quality. To control the disease, more attention should be paid on the host range of the pathogen and other regions where the disease caused by the pathogen might occur.The author(s) declare no conflict of interest.

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.