Pseudoplagiostoma myracrodruonis (Pseudoplagiostomataceae, Diaporthales): a new endophytic species from Brazil

Molecular phylogenetic and estimation of evolutionary divergence and biogeography of the family Schizoparmaceae and allied families (Diaporthales, Ascomycota)

The Diaporthales includes 32 families, many of which are important plant pathogens, endophytes and saprobes, e.g., members of the families Pseudoplagiostomataceae, Pyrisporaceae and Schizoparmaceae. Nucleotide sequences derived from five genetic loci including: ITS, LSU, TEF1-α, TUB2 and RPB2 were used for Bayesian evolutionary analysis to determine divergence times and evolutionary relationships within the Schizoparmaceae. Molecular clock analyses revealed that the ancestor of Schizoparmaceae split during the Upper Cretaceous period approximately 75.7 Mya (95 % highest posterior density of 60.3-91.3 Mya). Reconstructing ancestral state in phylogenies (RASP) with using the Bayesian Binary Markov chain Monte Carlo (BBM) Method to reconstruct the historical biogeography for the family Schizoparmaceae indicated its most likely origin in Africa. Based on taxonomic and phylogenetic analyses, the Pseudoplagiostomataceae and Pyrisporaceae relationships were clarified and a total of four species described herein. For Pseudoplagiostomataceae, three new species and one known species that include, Pseudoplagiostoma fafuense sp. nov., Ps. ilicis sp. nov., Ps. sanmingense sp. nov. and Ps. bambusae are described and a key of Pseudoplagiostomataceae is provided. With respect to Pyrisporaceae, we considered Pseudoplagiostoma castaneae to be a synonym of Pyrispora castaneae. In addition, a new species of Schizoparmaceae, Coniella fujianensis sp. nov. is described and illustrated.

Pseudoplagiostoma humilis sp. nov., a New Fungal Species Causing Shoot Blight and Dieback in Anacardium humile in Brazil

The cajuzinho do cerrado (Anacardium humile-Anacardiaceae), a shrub species native to Brazil, is harvested for multiple uses in food and medicine. Members of a harvesting community, near the municipality of Bonito de Minas, Minas Gerais state, Brazil reported characteristic symptoms of shoot blight and dieback reducing pseudofruit and seed production by this plant. This study aimed to identify the etiological agent of this disease. Two fungal isolates were obtained from symptomatic leaf samples and morphologically and molecularly characterized. The fungus was identified, based on morphological analyses, as a probable new species of Pseudoplagiostoma. Phylogenetic analyses based on a combination of DNA sequence data (nuc rDNA ITS1-5.8S-ITS2 region, tef1-α and tub2), confirmed this hypothesis. The isolates obtained were allocated to a distinct, well-supported clade (IB = 0.99, ML = 100%), placed as a unique lineage here proposed as a new species named Pseudoplagiostoma humilis. The pathogenicity test confirmed that this new species was the causal agent of shoot blight and dieback on A. humile. This is the fourteenth Pseudoplagiostoma species reported in the world and the third in Brazil.

Appressoria-Producing Sordariomycetes Taxa Associated with Jasminum Species

Appressoria are specialized structures formed by certain phytopathogenic fungi during the early stages of the infection process. Over the years, significant advancements have been made in understanding the formation, types, and functions of appressoria. Besides being formed primarily by fungal pathogens, many studies have reported their occurrence in other life modes such as endophytes, epiphytes, and saprobes. In this study, we observed the formation of appressoria in fungal genera that have been found associated with leaf spots and, interestingly, by a saprobic species. We used morphological descriptions and illustrations, molecular phylogeny, coalescent-based Poisson tree processes (PTP) model, inter- and intra-species genetic distances based on their respective DNA markers, and Genealogical Concordance Phylogenetic Species Recognition Analysis (GCPSR) to establish a new species (Pseudoplagiostoma jasmini), a Ciliochorella sp., and a new host record (Coniella malaysiana). The Ciliochorella sp. is reported as a saprobe, while Pseudoplagiostoma jasmini and Coniella malaysiana were found to be associated with leaf spots of Jasminum species. All three taxa produce appressoria, and this is the first study that reports the formation of appressoria by a Ciliochorella sp. and a Pseudoplagiostoma sp.

Taxonomy, Phylogeny, Divergence Time Estimation, and Biogeography of the Family Pseudoplagiostomataceae (Ascomycota, Diaporthales)

Species of Pseudoplagiostomataceae were mainly introduced as endophytes, plant pathogens, or saprobes from various hosts. Based on multi-locus phylogenies from the internal transcribed spacers (ITS), the large subunit of nuclear ribosomal RNA gene (LSU), partial DNA-directed RNA polymerase II subunit two gene (rpb2), the partial translation elongation factor 1-alpha gene (tef1α), and the partial beta-tubulin gene (tub2), in conjunction with morphological characteristics, we describe three new species, viz. Pseudoplagiostoma alsophilae sp. nov., P. bambusae sp. nov., and P. machili sp. nov. Molecular clock analyses on the divergence times of Pseudoplagiostomataceae indicated that the conjoint ancestor of Pseudoplagiostomataceae and Apoharknessiaceae occurred in the Cretaceous period. and had a mean stem age of 104.1 Mya (95% HPD of 86.0-129.0 Mya, 1.0 PP), and most species emerged in the Paleogene and Neogene period. Historical biogeography was reconstructed for Pseudoplagiostomataceae by the RASP software with a S-DEC model, and suggested that Asia, specifically Southeast Asia, was probably the ancestral area.

First Report of Mango Leaf Blotch Caused by Pseudoplagiostoma mangiferae in Taiwan

Mango (Mangifera indica L.) is an economically important tropical fruit in southern Taiwan. In February 2019, new leaf blotches distinct from anthracnose lesions were noticed on mango leaves in Meinong, Kaohsiung (N22°54'43.7" E120°32'59.3"). Symptoms were circular to irregular lesions with easily torn centers and were cream to light brown with dark brown margin on both leaf surfaces. Similar symptoms were observed on mango leaves in Yujing, Tainan (N23°07'31.3" E120°27'18.2") in July of the same year. We surveyed the disease incidence on 60 mango trees consisting of three cultivars, 'Irwin', 'Yu-win No.6' and a native cultivar in a commercial farm by randomly examining five shoots of each tree. The disease incidences of 'Irwin', the native cultivar and 'Yu-win No.6' were 25%, 37% and 73%, respectively. Diseased tissues from the two locations were surface sterilized and incubated on potato dextrose agar (PDA) for pathogen isolation. Seven isolates (Mgk3, TMg2-2.2, TMg3-1.2, TMg3-2.1, TMg4-1, TMg6-3, and TMg8-1.1) from different locations and cultivars were selected for further study. Pycnidia were produced on 7-day-old PDA cultures. Conidiogenous cells were hyaline and short cylindrical phialides. Conidia were hyaline, aseptate, thick-walled, 20-24 × 11-16 μm, and subcircular to ellipsoid with 1-2 large oil droplets and a markedly flat protruding hilum at the base. These morphological features presenting in the seven isolates were identified as a member of Pseudoplagiostoma (Cheewangkoon et al. 2010). Pathogenicity assays were conducted by the point inoculation method on 10 intact young leaves growing on 'Irwin' mango plants in a greenhouse at 20-25℃. Each leaf was inoculated at six points on the abaxial surface with point inoculation. Each point was inoculated with a 10 μl conidial suspension (106 conidia/ml) of isolate TMg 8-1.1. Sterilized water was used as control. Shoots with inoculated leaves were covered with translucent plastic bags for 2 days. At 7 days post-inoculation (dpi), 70% of conidia inoculated points (n = 60) displayed symptoms resembling the field symptoms, but sterilized water inoculated points (n = 60) did not. The six other isolates were inoculated on detached leaves by the point inoculation method. All inoculated leaves were maintained in humid containers at 25℃ with 12 h light/dark regime, and displayed similar lesions at 7 dpi. Fungi re-isolated from the symptomatic leaves showed the same morphological characteristics observed in the Pseudoplagiostoma originally isolated from diseased tissues. Internal transcribed spacer (ITS), TUB2 and LSU gene sequences of the seven isolates (ITS accession nos.: MN818659 to MN818665; TUB2 accession nos.: MW415921 to MW415927; LSU accession nos.: MN876849 to MN876855) were amplified with primer sets ITS4/V9G, T1/Bt-2b and LSU1Fd/LR5, respectively, and used for molecular identification (Cheewangkoon et al. 2010). The seven isolate were 95.8%, 99-100% and 99.8% identical to Pseudoplagiostoma mangiferae Dayarathne, Phookamsak & K. D. Hyde KUMCC 18-0179 (the ex-type strain) for the ITS gene (MK084824), TUB2 gene (MK084823) and LSU gene (MK084825), respectively. Phylogenetic analysis based on concatenated sequences of ITS and LSU genes was performed by the Maximum Likelihood method. All seven isolates were clustered in a well-supported clade with P. mangiferae KUMCC 18-0179 with 100% bootstrap value. Based on the pathogenicity and morphological characteristics, the pathogen was identified as P. mangiferae which was reported as a new species associated with mango leaf blight in Yunnan, China (Bezerra et al. 2019; Cheewangkoon et al. 2010; Crous et al. 2012; Crous et al. 2018; Phookamsak et al. 2019; Suwannarach et al. 2016). The newly emerging leaf blotch may become a prevalent disease of mango in future.