Phyllosticta Capitalensis Research Articles

First Report of Phyllosticta capitalensis Causing Black Freckle Disease on Rubus chingii in China.

Rubus chingii is used as an important traditional Chinese medicine, and belongs to the family Rosaceae. The fruit has multiple pharmacological activities, including antioxidant, anti-inflammatory, and improving cognitive impairment (Na Han et al. 2012). In June 2019, a new fungal infection was observed on the leaves of R. chingii in Qiandongnan Miao and Dong Autonomous Prefecture, Guizhou Province, China, forming small lesions with reddish-brown edges along leaf veins. Over 500 plants were surveyed, and nearly 20% of the plants were symptomatic. The diseased plants grew poorly and appeared stunted, and severely affected plants died. Five symptomatic leaves were randomly collected from the field and washed with tap water and distilled water successively. The edges of infected leaf tissue were cut into small pieces (4 to 5 mm2), surface sterilized with 70% ethanol for 30 s and 0.1% HgCl2 for 1 minute, and then rinsed three times in sterile distilled water (Chen et al. 2016). The same fungus was isolated from 41 pieces. The hyphae of a representative isolate were gray, the colony surface was granular, the edges were uneven and white, and the culture turned black over time with black spherical conidia. Conidia were nearly elliptical, unicellular, and each with a hyaline, unstable apical appendage, 3 to 10 µm long. The size of conidia was 10 to 18 μm in length and 4 to 8 μm in width. These morphological characteristics are consistent with those described for the fungus Phyllosticta capitalensis. (Wikee et al. 2013). For an accurate identification, genomic DNA of a representative isolate of the pathogen was extracted to amplify the internal transcribed spacer (ITS) region, the transcription elongation factor (tefa-1), and actin (ACT) genes with the ITS1/ITS4, EF1-728F/EF1-986R, and ACT-512F/ACT-783R (Cheng, L. L. ,et al. 2019), respectively. The ITS, tefa-1 and actin gene sequences were deposited in GenBank and assigned accession numbers MW308365, MW714380 and MW714381, respectively. BLAST search analysis of GenBank (NCBI) showed that the sequences had 100% similarity with those of Phyllosticta capitalensis (GenBank accession no. ITS, MN548091; tefa-1, MN958711; and ACT, MN565575). The pathogenicity of Phyllosticta capitalensis was verified using six healthy detached leaves from healthy R. chingii plants around 40 cm tall. A total of nine plants were used, and three leaves from each plant were artificially inoculated. Each wound was inoculated with conidial suspension (106 mL-1), while the control leaves were coated by sterile water. All the treated plants were covered with plastic bags for 2 days, incubated at 28ºC and 85% relative humidity, with a 12-hour photoperiod. After 15 days following inoculation, the injured leaves showed similar symptoms to the above-mentioned lesions, while the control and uninjured leaves were still healthy. P. capitalensis were reisolated from inoculated leaves, fulfilling Koch's postulates. P. capitalensis is an endophyte, widely distributed in various host plants in China. (Lu, J. M, et al. 2016). To the best of our known, this is the first report of black freckle disease caused by P. capitalensis on Rubus chingii in China. P. capitalensis is a destructive plant pathogen with an unusually broad host range and our findings will be useful for its management and for further research. The author(s) declare no conflict of interest.

First report of secondary leaf fall in rubber trees caused by Phyllosticta capitalensis in the Eastern Plains of Colombia

Rubber trees (Hevea brasiliensis) are planted on 65,545 hectares in Colombia (Minagricultura, 2021). Since September 2020, unusual leaf spots were observed on mature leaves of rubber trees (clones RRIM 600 and FX 3864), in three plantations in the Eastern Plains region. The regular spots (usually 1–3 per leaf) were up to 8 mm in diameter, with a clearly defined brownish to blackish margin and a necrotic centre (Figure 1). The disease led to secondary leaf fall, causing up to 30% defoliation. Diseased leaves were collected and transferred to the laboratory for diagnosis. After surface disinfection with ethanol (70%) and sodium hypochlorite (2%), 0.5 cm2 sections of diseased tissue were transferred to potato dextrose agar (PDA) medium and incubated at 28°C for two weeks. The developing colonies had irregular borders and gradually turned dark greyish-green in colour, then black (Figure 2a). Sporulation was induced on a parboiled rice medium (Figure 2b) under controlled conditions (12 hr photoperiod, relative humidity 50%, 26 ±2°C). Pycnidia with conidia were observed after 44 days. Conidia (Figure 3a) were small, single-celled, hyaline, ovoid to elongate, measuring 8–11×5-6 μm. Pycnidia were dark, ostiolate and lenticular to globose (Figure 3b). These morphological characters were consistent with the descriptions of Phyllosticta species (Wikee et al., 2013). Two isolates (14_SAT and 15_SAT) were deposited in the Agrosavia fungi collection and used for DNA-based identification. The ITS, TEF1 and ACT genes were amplified and sequenced using primers ITS5/ITS4 (White et al., 1990), EF1-728F/EF1-986R and ACT-512F/ACT-783R (Carbone & Kohn, 1999), respectively. BLASTn analysis showed that the ITS (GenBank Accession Nos. OL898551 and OL957043) had 100% identity with P. capitalensis strain CBS128856 (OL957169), ACT (OM782674 and OM782675) had 100% identity with P. capitalensis isolate CPC25327 (KY855640), and TEF1 (OM782672 and OM782673) had 100% identity with Guignardia mangiferae (syn. P. capitalensis) strain CBS 100175 (FJ538378). A multilocus phylogenetic analysis revealed isolates clustered together in a clade with reference strains of P. capitalensis (Figure 4). For inoculation studies, H. brasilisensis seedlings of variety RRIM 600 were transferred to a growth chamber (24 hr dark initially, thereafter 12 hr light/dark; 26°C; relative humidity >90%). The abaxial surface of three healthy stage B leaves were sprayed with a conidial suspension of isolate 14_SAT (1×106 spores ml 1), while three control leaves were sprayed with sterile water. The experiment was repeated after one month with the 15_SAT isolate. Chlorotic lesions were observed 48 hours after inoculation and necrotic spots appeared after five days. The pathogen was successfully re-isolated on PDA medium and morphologically confirmed as P. capitalensis. No symptoms were observed on the control leaves. Phyllosticta capitalensis has been identified previously as a rubber foliar pathogen in Sri Lanka (Herath et al., 2019). Narayanan & Reju (2020) isolated the fungus from rubber leaves in India showing the same symptoms as reported here. This is the first report of P. capitalensis causing secondary leaf fall in rubber plantations in Colombia. Further monitoring of this new disease is required to determine its impact. The authors thank Mavalle and Rubberland for allowing leaf sampling in their plantations. This work was carried out with financial support from Agrosavia (Project 1001205) and CIRAD.

First report of Phyllosticta capitalensis causing leaf spot of Japanese privet (Ligustrum japonicum) in Iran

First report of Phyllosticta capitalensis causing leaf spot of Japanese privet (Ligustrum japonicum) in Iran

Revealing the endophytic mycoflora in tea (Camellia sinensis) leaves in Sri Lanka: the first comprehensive study

Endophytic fungi are a diverse group of microorganisms that live asymptomatically in healthy tissues of host and they have been reported from all kinds of plant tissues such as leaves, stems, roots, flowers, and fruits. In this study, fungal endophytes associated with tea leaves (Camellia sinensis) were collected from Kandy, Kegalle, and Nuwara Eliya districts in Sri Lanka and were isolated, characterized, and identified. A total of twenty endophytic fungal isolates belonging to five genera were recovered and ITS-rDNA sequence data were used to identify them. All isolated endophytic fungal strains belong to the phylum Ascomycota and the majority of these isolates were identified as Colletotrichum species. Phyllosticta capitalensis was the most commonly found fungal endophyte in tea leaves and was recorded in all three districts where the samples were collected. This is the very first investigation on fungal endophytes associated with C. sinensis in Sri Lanka based on molecular sequence data. In addition, a comprehensive account of known endophytic fungi reported worldwide on Camellia sinensis is provided.

Neuroprotective Activities of Constituents from Phyllosticta capitalensis, an Endophyte Fungus of Loropetalum chinense var. rubrum.

One new dioxolanone derivative, guignardianone G (1) and twelve known compounds (2-13) were isolated from the 95 % ethanol extract of the plant endophytic fungus Phyllosticta capitalensis cultured in rice medium. Among these known compounds, isoaltenuene (3), brassicasterol (7), 5,6-epoxyergosterol (8), citreoanthrasteroid A (9), demethylincisterol A (10), and chaxine C (11) were reported from Phyllosticta sp. for the first time. The structure of 1 was elucidated by 1D- and 2D-NMR experiments and HR-ESI-MS data analysis, and its absolute configuration was established through the comprehensive use of the methods of modified Mosher methods, calculations of ECD spectra and optical rotation values. The neuroprotective activity of compounds (1-9, 11-13) were evaluated on PC12 cells damage induced by glutamate, and compounds 9 and 12 showed potential neuroprotective activities with half effective concentration (EC50 ) of 24.2 and 33.9 μM, respectively.

Carbon utilization and growth-inhibition of citrus-colonizing Phyllosticta species

The genus Phyllosticta includes both endophytic and phytopathogenic species that occur on a broad range of plant hosts, including Citrus. Some pathogenic species cause severe disease, such as Phyllosticta citricarpa, the causal agent of Citrus Black Spot (CBS). In contrast, other species, such as Phyllosticta capitalensis, have an endophytic lifestyle in numerous plant hosts. Carbon utilization capabilities are hypothesized to influence both host range and lifestyle, and are in part determined by the set of Carbohydrate Active Enzyme (CAZyme) encoding genes of a species. In this study, carbon utilization capabilities of five Phyllosticta species were determined, as well as the CAZyme repertoire (CAZome) encoded in their genomes. Little variation was found among species in terms of carbon utilization capabilities and CAZome. However, one of the tested carbon sources, sugar beet pulp (SBP), inhibited growth of the plant pathogens, also when combined with another carbon source, while endophytic species remained unaffected.

Effects of Pesticides on the Diversity of Endophytic Fungi in Tea Plants.

We examined the effects of agrochemicals on the endophytic fungal community associated with tea plants. Endophytic fungi were isolated from four different tea plant tissues (bark, xylem, old leaves, new leaves) collected from pesticide-treated and untreated plots. In pesticide-treated plot, the acaricides, fungicides, and insecticides are typically applied 3 times each year. The infection rate was slightly lower in the pesticide-treated plot, but the difference between plots was not statistically significant. Colletotrichum camelliae, Phyllosticta capitalensis, and Pleosporales sp. were common endophytes in both plots. Among a total of 41 fungal species, only 21 were considered common endophytes. Colletotrichum pseudomajus was the predominant endophyte in the bark tissue in the untreated plot, whereas C. camelliae was predominant in the pesticide-treated plot. Paraphaeosphaeria neglecta and Phoma bellendis were predominant in the xylem tissues of samples from the untreated and treated plots, respectively. Colletotrichum camelliae was the most commonly found species in leaf tissues in both plots, but the colonization frequency was significantly lower in the pesticide-treated plot. Species richness was not affected by pesticide treatment. The community structure of endophytic fungi in stem tissues (bark and xylem) differed significantly between plots, but leaf tissue endophytic fungal community structure was not significantly influenced by pesticide treatment.

Bioactivity of Crude Extracts of Secondary Metabolites of the Endophytes Phyllosticta capitalensis (Tg06) and Curvularia sp. (G6-32) against Aedes aegypti Larvae (L.1762)

Bioactivity of Crude Extracts of Secondary Metabolites of the Endophytes Phyllosticta capitalensis (Tg06) and Curvularia sp. (G6-32) against Aedes aegypti Larvae (L.1762)

Diversity of Endophytic Fungi of Psidium guajava (Myrtaceae) and Their Antagonistic Activity against Two Banana Pathogens

Aims: The present study was carried out to determine the diversity of endophytic fungi that colonize the leaves of Psidium guajava, and to evaluate their antagonistic activity against Fusarium oxysporum f.sp. cubense and Mycosphaerella fijiensis which are the two main phytopathogens of banana plants.
 Place and Duration of Study: The research was carried out at Microbiology Laboratory, Faculty of Sciences, University of Yaoundé I and Microbiology Laboratory, Faculty of Biotechnologies, University of Agronomic Sciences and Veterinary Medicine Bucharest, between April 2018 and February 2020.
 Methodology: Fragments of surface sterilized leaves of Psidium guajava were inoculated on Potato Dextrose Agar supplemented with chloramphenicol. The isolated and purified endophytic fungi were identified based on their macroscopic and microscopic characters using a mycological atlas as guide. The non-sporulating isolates were identified by comparing the ITS regions of their DNA to those of known fungi registered in the GenBank database. The antagonistic activity of the endophytic fungi isolated against Fusarium oxysporum and Mycosphaerella fijiensis was screened using dual culture method.
 Results: A total of 28 endophytic fungal were isolated from the leaves of Psidium guajava corresponding to a colonization frequency of 33.33%. These isolates were identified as: Aspergillus sp., Botryosphaeria sp., Fusarium sp., Neoscytalidium sp., Xylaria sp., Phyllosticta capitalensis, Cercospora apii, Xylaria longipes, Phomopsis sp., Phomopsis asparagi, Aspergillus versicolor, Pallidocercospora thailandica, and Xylaria grammica that belonged to the Deuteromycota and Ascomycota divisions. These endophytic fungi inhibited the growth of Fusarium oxysporum f.sp. cubense and Mycosphaerella fijiensis with the percentage inhibition varying respectively from 23.25% to 73.52% and from 21.36% to 100%. The species Botryosphaeria sp., Phomopsis sp., Phomopsis asparagi, and Xylaria longipes exhibited the greatest activity.
 Conclusion: The leaves of Psidium guajava have a fairly varied diversity of endophytic fungi. These endophytic fungi can serve as potential biological control agents against Panama and Sigatoka diseases of banana and also would produce secondary metabolites with antifungal properties.

Diversity of endophytic fungi from the leaves of Vaccinium dunalianum.

This study was focus on investigating the community composition of endophytic fungi in the leaves of Vaccinium dunalianum Wight. Based on a combination of morphological features and molecular evidence, 239 endophytic fungal isolates belonging to 33 genera including 62 species were obtained and identified. By comparing the relative abundance (RA) values, the most frequent species belonged to Phyllosticta and Guignardia with RA of 26·78 and 14·22% respectively. Of which, the strains P. capitalensis and G. mangiferae with potential antimicrobial activity were the dominant endophytes to the sampling of leaves. A high diversity of endophytic fungi from V. dunalianum leaves was observed with high species richness S (62), Margalef index D' (11·1386), Shannon-Wiener index H' (3·2588), Simpson's diversity index Ds (0·9179), probability of interspecific encounter index (0·9218), and evenness Pielou index J (0·7896) but a low dominant index λ (0·0821). SIGNIFICANCE AND IMPACT OF THE STUDY: The isolated 239 endophytic fungal strains belong to 33 genera, 62 species, in which a high diversity of endophytic fungi was observed in Vaccinium dunalianum leaves. In this study, two taxa Phyllosticta capitalensis and Guignardia mangiferae with potential antimicrobial activity were the dominant endophytes. This is a promising source of natural bioactive compounds for future agro-industry application.

First Report of Castor Dark Leaf Spot Caused by Phyllosticta capitalensis in Zhanjiang, China

Castor (Ricinus communis L.) is an important oil crop. Leaf spots on castor with disease incidence of about 22.5% have been observed on about 2,000 plants in a field located in Zhanjiang (21.17N, 110.18E), China, since 2016. Initial leaf symptoms were round spots with gray centers, surrounded by yellow halos. Ultimately, the spots then gradually spread and merged. Six samples of symptomatic leaves were collected from six diseased plants, and they were surface disinfested before isolation. Potato dextrose agar (PDA) was used to culture pathogens. Successively, pure cultures were obtained by transferring hyphal tips to new PDA plates. A total of 15 isolates were obtained from the affected leaves. Two single-spore isolates (RiL-1 and RiL-2) were obtained and confirmed to be identical based on morphological characteristics. Therefore, the representative isolate RiL-1 was selected for further study on the morphological and molecular characteristics. The colony of isolate RiL-1 was about 4 cm in diameter on a PDA plate in 5 days, dark green with a granular surface, and irregular white (later turning black) edge. Conidia were single-celled, oval, narrow at the end with a single apical appendage, and 8.9 to 12.6 × 4.0 to 7.5 µm (n = 40). Morphological characteristics of isolate RiL-1 were consistent with the description of Phyllosticta capitalensis (Wikee et al. 2013). The internal transcribed spacer (ITS) region, translation elongation factor 1-α (tef1-α), and actin (ACT) were amplified using primers ITS1/ITS4, EF1-728F/EF1-986R (Druzhinina et al. 2005), and ACT-512F/ACT-783R (Wikee et al. 2013), respectively. Sequences were deposited in GenBank with accession numbers MN548089 for ITS, MN565576 for tef1-α, and MN565573 for ACT. BLASTn analysis demonstrated that these sequences were 99 to 100% similar to the corresponding ITS (MF170677), tef1-α (KU716086), and ACT (KY855659) sequences of P. capitalensis. Also, by the neighbor-joining method, a phylogenetic tree showed that isolate RiL-1 (MN548089) clustered together with P. capitalensis (MF800912) from China. From the combination of the morphological and molecular characteristics, isolate RiL-1 was determined to be P. capitalensis. A pathogenicity test was performed in a greenhouse with 80% relative humidity at 25 to 30°C. Sterilized cotton balls were immersed in spore suspension (1 × 10⁶ spores/ml) or sterile water for 1 min. Sixteen healthy plants were divided into two groups (wounded group and unwounded group). Spore-containing cotton balls covered the inoculated sites on four plants in the wounded group and four in the unwounded group, with the same procedure for the water-only cotton balls, and kept for 48 h before removing the cotton. After 15 days, disease symptoms were observed on both wounded and unwounded leaves, whereas control plants (both wounded and unwounded) remained healthy. Morphological characteristics and the ITS sequences of the fungal isolates reisolated from the diseased leaves were identical to those of RiL-1. P. capitalensis has caused leaf spot on various host plants around the world (Wikee et al. 2013), including on tea plant in China (Cheng et al. 2019) and oil palm in Malaysia (Nasehi et al. 2020), but it has not been reported on castor. Thus, this is the first report of P. capitalensis causing leaf spot on castor. This study will provide an important reference for the control of the disease. The epidemiology of P. capitalensis on castor should be investigated in further research.

Genomic Sequencing of Phyllosticta citriasiana Provides Insight Into Its Conservation and Diversification With Two Closely Related Phyllosticta Species Associated With Citrus.

Phyllosticta capitalensis, Phyllosticta citricarpa, and Phyllosticta citriasiana are three very important Phyllosticta species associated with citrus. P. capitalensis is an endophyte fungus of citrus while P. citricarpa can cause black spot of citrus (e.g., oranges and mandarins). P. citriasiana was identified recently which is the causal agent of the pomelo tan spot. Here, we present the ∼34 Mb genome of P. citriasiana. The genome is organized in 92 contigs, encompassing 9202 predicted genes. Comparative genomic analyses with two other Phyllosticta species (P. citricarpa and P. capitalensis) associated with citrus was conducted to understand their evolutionary conservation and diversification. Pair-wise genome alignments revealed that these species are highly syntenic. All species encode similar numbers of CAZymes and secreted proteins. However, the molecular functions of the secretome showed that each species contains some enzymes with distinct activities. The three Phyllosticta species investigated shared a core set of 7261 protein families. P. capitalensis had the largest set of orphan genes (1991), in complete contrast to that of P. citriasiana (364) and P. citricarpa (262). Most of the orphan genes are functionally unknown, but they contain a certain number of species-specific secreted proteins. A total of 23 secondary metabolites biosynthesis clusters were identified in the three Phyllosticta species, 21 of them being highly conserved among these species while the remaining two showed whole cluster gain and loss polymorphisms or gene content polymorphisms. Taken together, our study reveals insights into the genetic mechanisms of host adaptation of three species of Phyllosticta associated with citrus and paves the way to identify effectors that function in infection of citrus plants.

First report of Phyllosticta capitalensis causing leaf spots on ornamental Magnolia grandiflora and Syringa reticulata in Iran

Magnolia grandiflora is a medicinal and horticultural plant species in the family Magnoliaceae which is native to North America (Li et al., 2013). Syringa reticulata is a tree in the family Oleaceae which is native to Japan (Green et…

Tibouchina granulosa (Vell.) Cogn (Melastomataceae) as source of endophytic fungi: isolation, identification, and antiprotozoal activity of metabolites from Phyllosticta capitalensis.

Endophytes are microorganisms that form symbiotic relationships with their own host. Included in this group are the species Phyllosticta capitalensis, a group of fungi that include saprobes that produce bioactive metabolites. The present study aimed to identify the cultivable endophytic fungal microbiota present in healthy leaves of Tibouchina granulosa (Desr.) Cogn. (Melastomataceae) and investigate secondary metabolites produced by a strain of P. capitalensis and their effects against both Leishmania species and Trypanossoma cruzi. Identification of the strains was accomplished through multilocus sequencing analysis (MLSA), followed by phylogenetic analysis. The frequency of colonization was 73.66% and identified fungi belonged to the genus Diaporthe, Colletotrichum, Phyllosticta, Xylaria, Hypoxylon, Fusarium, Nigrospora, and Cercospora. A total of 18 compounds were identified by high-resolution mass spectrum analysis (UHPLC-HRMS), including fatty acids based on linoleic acid and derivatives, from P. capitalensis. Crude extracts had activity against Leishmania amazonensis, L. infantum, and Trypanosoma cruzi, with inhibitory concentration (IC50) values of 17.2μg/mL, 82.0μg/mL, and 50.13μg/mL, respectively. This is the first report of the production of these compounds by the endophytic P. capitalensis isolated from T. granulosa.

Phyllosticta capitalensis Causes Leaf Spot on Tea Plant (Camellia sinensis) in China

<i>Phyllosticta capitalensis</i> Causes Leaf Spot on Tea Plant (<i>Camellia sinensis</i>) in China

Phyllosticta citricarpa and sister species of global importance to Citrus.

SummarySeveral Phyllosticta species are known as pathogens of Citrus spp., and are responsible for various disease symptoms including leaf and fruit spots. One of the most important species is P. citricarpa, which causes a foliar and fruit disease called citrus black spot. The Phyllosticta species occurring on citrus can most effectively be distinguished from P. citricarpa by means of multilocus DNA sequence data. Recent studies also demonstrated P. citricarpa to be heterothallic, and reported successful mating in the laboratory. Since the domestication of citrus, different clones of P. citricarpa have escaped Asia to other continents via trade routes, with obvious disease management consequences. This pathogen profile represents a comprehensive literature review of this pathogen and allied taxa associated with citrus, focusing on identification, distribution, genomics, epidemiology and disease management. This review also considers the knowledge emerging from seven genomes of Phyllosticta spp., demonstrating unknown aspects of these species, including their mating behaviour.Taxonomy Phyllosticta citricarpa (McAlpine) Aa, 1973. Kingdom Fungi, Phylum Ascomycota, Class Dothideomycetes, Order Botryosphaeriales, Family Phyllostictaceae, Genus Phyllosticta, Species citricarpa.Host rangeConfirmed on more than 12 Citrus species, Phyllosticta citricarpa has only been found on plant species in the Rutaceae.Disease symptoms P. citricarpa causes diverse symptoms such as hard spot, virulent spot, false melanose and freckle spot on fruit, and necrotic lesions on leaves and twigs.Useful websitesDOE Joint Genome Institute MycoCosm portals for the Phyllosticta capitalensis (https://genome.jgi.doe.gov/Phycap1), P. citriasiana (https://genome.jgi.doe.gov/Phycit1), P. citribraziliensis (https://genome.jgi.doe.gov/Phcit1), P. citrichinaensis (https://genome.jgi.doe.gov/Phcitr1), P. citricarpa (https://genome.jgi.doe.gov/Phycitr1, https://genome.jgi.doe.gov/Phycpc1), P. paracitricarpa (https://genome.jgi.doe.gov/Phy27169) genomes.All available Phyllosticta genomes on MycoCosm can be viewed at https://genome.jgi.doe.gov/Phyllosticta.

First Report of Leaf Spot on Oil Palm Caused by Phyllosticta capitalensis in Malaysia

HomePlant DiseaseVol. 104, No. 1First Report of Leaf Spot on Oil Palm Caused by Phyllosticta capitalensis in Malaysia PreviousNext DISEASE NOTES OPENOpen Access licenseFirst Report of Leaf Spot on Oil Palm Caused by Phyllosticta capitalensis in MalaysiaA. Nasehi, H. Sathyapriya, and M. Y. WongA. Nasehihttp://orcid.org/0000-0002-5926-0742Institute of Plantation Studies, Universiti Putra Malaysia, 43400 Serdang, Selangor, MalaysiaSearch for more papers by this author, H. SathyapriyaInstitute of Tropical Agriculture and Food Security, Universiti Putra Malaysia, 43400 Serdang, Selangor, MalaysiaSearch for more papers by this author, and M. Y. Wong†Corresponding author: M. Y. Wong; E-mail Address: muiyun@upm.edu.myhttp://orcid.org/0000-0002-6944-4860Institute of Plantation Studies, Universiti Putra Malaysia, 43400 Serdang, Selangor, MalaysiaDepartment of Plant Protection, Faculty of Agriculture, Universiti Putra Malaysia, 43400 Serdang, Selangor, MalaysiaSearch for more papers by this author AffiliationsAuthors and Affiliations A. Nasehi1 H. Sathyapriya2 M. Y. Wong1 3 † 1Institute of Plantation Studies, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia 2Institute of Tropical Agriculture and Food Security, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia 3Department of Plant Protection, Faculty of Agriculture, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia Published Online:6 Nov 2019https://doi.org/10.1094/PDIS-06-19-1232-PDNAboutSectionsSupplemental ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat Oil palm (Elaeis guineensis Jacq.) is the most economically important crop in Malaysia and the world’s highest yielding oil crop. In March 2018, irregular spots with gray centers, dark brown edges, and chlorotic halos were observed on the leaves of oil palm trees of Tenera genotype planted at Block A, University Agriculture Park, Universiti Putra Malaysia, Malaysia. The area of production is 8 ha of conventional farming with temperature and humidity ranging from 33 to 34°C and 30 to 70%, respectively. There were a total of 1,192 oil palm trees in the area analyzed, and the disease incidence was estimated to be approximately 20%. Twelve leaf sections (5 mm2) of four diseased leaves from four different symptomatic oil palm trees were surface sterilized in 1% sodium hypochlorite for 2 min, rinsed twice with distilled water, dried on sterilized tissue paper, plated on potato dextrose agar (PDA) plates, and incubated at 27 ± 1°C for 14 days in the dark. A total of 12 single-spore isolates were obtained from all sampled leaf tissues. The single colonies of all fungal isolates were olivaceous greenish to olivaceous black with an irregular light olive margin on PDA. Conidia were obpyriform or nearly elliptic, unicellular, with a hyaline, unstable apical appendage, 5 to 12 µm long. The size of conidia was 10 to 15 μm in length and 6 to 8 μm in width. These morphological characters were consistent with the original description of Phyllosticta capitalensis (Glienke et al. 2011; Hennings 1908). For fungal identification to species level, the internal transcribed spacer region (ITS) of the representative isolate UPM-Ph1 was amplified utilizing the universal primers ITS5/ITS4 (White et al. 1990) and then sequenced. The 620-bp ITS sequence was deposited in GenBank under accession number MH699964. The phylogenetic analysis confirmed that the isolate UPM-Ph1 belonged to P. capitalensis, and it shares 100% homology with the ITS sequence of the reference pathogenic P. capitalensis strain CPC18884 (GenBank JF261465), which was isolated from the host Stanhopea graveolens in Brazil, as reported by Glienke et al. (2011). Pathogenicity testing was conducted by artificial inoculation of healthy oil palm (Tenera GH 500 series) leaves with isolate UPM-Ph1 under the conditions of 9-h day/15-h night cycle and using LED white light. Four leaves were wound inoculated in three parts with a sterile scalpel and pipetting a 10-µl droplet of a conidial suspension (106 conidia/ml) on each wound. Another four leaves were wound inoculated with sterilized distilled water and served as a control. All inoculated leaves and control leaves were incubated in a chamber with 98% relative humidity at 27 ± 1°C. After 7 days, typical lesions identical to those observed in the field appeared on the inoculated leaves but not on control leaves. P. capitalensis was successfully reisolated only from the inoculated leaves and identified by morphological observations. The pathogenicity test was repeated, and the same typical lesions were observed. P. capitalensis has been reported as a weak plant pathogen that causes various diseases in plants (Wikee et al. 2013a, 2013b). Unsuccessful reisolation of the fungus from the control leaves confirmed that the control plants were not already latently infected with the pathogen. To our knowledge, this is the first report of P. capitalensis causing leaf spot disease of oil palm in Malaysia. This pathogen is capable of affecting the health and yield of oil palm trees in the plantations substantially if no control measure is in place. Therefore, further investigation is needed to determine the distribution of P. capitalensis in oil palm plantations in Malaysia.The author(s) declare no conflict of interest.

Chemical Investigation Of Secondary Metabolites Produced By Mangrove Endophytic Fungus Phyllosticta Capitalensis

Chemical investigation of endophytic fungus Phyllosticta capitalensis, isolated from the hypocotyls of the Chinese mangrove Bruguiera sexangula led to the isolation of eight known secondary metabolites, including four meroterpenes guignardone A (1), 12-hydroxylated guignardone A (2), guignardone J (3), guignardone M (4), and four polyketides xenofuranone B (5), 6,8-dihydroxy-5-methoxy-3-methyl-1H-isochromen-1-one (6), regiolone (7), 3,4-dihydroxybenzoic acid (8). Their structures were elucidated unambiguously based on the comprehensive spectroscopic analysis and comparison with literature data. This is the first report of these compounds being isolated from this fungal species. All compounds isolated were subjected to antimicrobial and cytotoxic activities evaluation.

Meroterpenoids with diverse ring systems and dioxolanone-type secondary metabolites from Phyllosticta capitalensis and their phytotoxic activity

Twenty meroterpenoids with diverse ring systems including five new ones (1, 2, 5, 6, and 15), together with two new (23 and 24) and two known dioxolanone-type secondary metabolites were isolated from Phyllosticta capitalensis, an endophytic fungus from Cephalotaxus fortunei Hook. Compound 1 was the first example with a 9,14-seco ring A and a five-membered ring B in guignardone derivatives. Compound 2 represented a novel guignardone derivative possessing a 5/7/6/5 ring system with CH2-7 attached to C-4 rather than C-6 in ring D. The structures of all new compounds were elucidated using spectroscopic data analyses and electronic circular dichroism comparison. The phytotoxic effects of compounds 1–24 on Lactuca sativa and Lolium perenne were evaluated. Compound 22 showed inhibition activity on the shoots growth of L. sativa and L. perenne, as well as the roots growth of L. perenne.

Comparative genome analysis of Phyllosticta citricarpa and Phyllosticta capitalensis, two fungi species that share the same host

BackgroundCitrus are among the most important crops in the world. However, there are many diseases that affect Citrus caused by different pathogens. Citrus also hosts many symbiotic microorganisms in a relationship that may be advantageous for both organisms. The fungi Phyllosticta citricarpa, responsible for citrus black spot, and Phyllosticta capitalensis, an endophytic species, are examples of closely related species with different behavior in citrus. Both species are always biologically associated and are morphologically very similar, and comparing their genomes could help understanding the different lifestyles. In this study, a comparison was carried to identify genetic differences that could help us to understand the biology of P. citricarpa and P. capitalensis.ResultsDrafts genomes were assembled with sizes close to 33 Mb for both fungi, carrying 15,206 and 14,797 coding sequences for P. citricarpa and P. capitalensis, respectively. Even though the functional categories of these coding sequences is similar, enrichment analysis showed that the pathogenic species presents growth and development genes that may be necessary for the pathogenicity of P. citricarpa. On the other hand, family expansion analyses showed the plasticity of the genome of these species. Particular families are expanded in the genome of an ancestor of P. capitalensis and a recent expansion can also be detected among this species. Additionally, evolution could be driven by environmental cues in P. citricarpa.ConclusionsThis work demonstrated genomic differences between P. citricarpa and P. capitalensis. Although the idea that these differences could explain the different lifestyles of these fungi, we were not able to confirm this hypothesis. Genome evolution seems to be of real importance among the Phyllosticta isolates and it is leading to different biological characteristics of these species.