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Fruit rot is one of the most important diseases affecting watermelon (Citrullus lanatus). This disease has been associated with substantial economic losses. In May 2022, fruit rot on watermelons was found during the post-harvest storage phase in local markets located in Chiang Mai Province, Thailand. The causal fungi were isolated from lesions and identified as Lasiodiplodia theobromae based on morphological characteristics and a phylogenetic analysis of combined sequences of the internal transcribed spacer (ITS) of ribosomal DNA, β-tubulin (tub), RNA polymerase II subunit (rpb2), and the translation elongation factor 1-alpha (tef1-α) genes. Subsequently, pathogenicity tests were conducted and the results showed that the isolated fungi caused symptoms of fruit rot in inoculated fruit specimens. This result was consistent with symptoms that were observed in local markets. This is the first report of post-harvest fruit rot on watermelons caused by L. theobromae in Thailand. [ABSTRACT FROM AUTHOR]

A new edible wild mushroom species, described herein as Panus sribuabanensis, was collected from local markets and natural forests located in northern Thailand. This species is characterized by its medium to large-sized basidiomata, broadly ellipsoid to ellipsoid-shaped basidiospores, dimitic hyphal system, and the absence of hyphal pegs. A molecular phylogenetic analysis of combined the internal transcribed spacer (ITS) and large subunit (nrLSU) of nuclear ribosomal DNA sequences supported the monophyly of P. sribuabanensis as a distinct lineage within the genus Panus. Full description, illustrations, color photographs, and a phylogenetic tree to show the placement of P. sribuabanensis are provided. The dried mushroom showed a nutritional composition within the range of 2.58%–2.67% for fat content, 27.10%–27.98% for protein, and 43.97%–44.10% for carbohydrates. The ethanolic extracts from this mushroom exhibited a total phenolic content ranging from 0.66 to 0.74 mg GAE/g dry weight (dw). Moreover, the antioxidant activities of ethanolic extracts evaluated by the 2,2-diphenyl-1-picrylhydrazyl (0.90–1.08 mg TE/g dw) and ferric reducing antioxidant power (0.93–1.08 mg TE/g dw) assays demonstrate higher activity compared to the 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) assay (0.44–0.51 mg TE/g dw). The outcomes of this study provide significant information on the nutritional value, phenolic content, and antioxidant activity potential of this new mushroom species discovered in northern Thailand. [ABSTRACT FROM AUTHOR]

Pluteus is a species-rich genus of saprotrophic agaric in the family Pluteaceae and is widely distributed in tropical, subtropical, and temperate areas throughout the world. Some species in this genus are threatened species according to the International Union for Conservation of Nature (IUCN) red list. During investigations of agarics in northern Thailand, four Pluteus taxa were collected. Morphological characteristics and phylogenic analyses were investigated. Two new species, namely P. chandrasikuliae and P. saisamorniae, were introduced. Pluteus chandrasikuliae is characterized by its relatively large basidiomata, an applanate, dark brown scaly pileus with a cutis pileipellis, two types of hymenial cystidia viz. irregular, as well as diverticulate cells and lageniform cells. In accordance with the phylogenetic results, this new species belongs to the Pluteus sect. Celluloderma. Moreover, P. saisamorniae is distinguished by a plano-convex with a broad umbo, dark brown minute squamules pileus, light brown lamellar edges, greyish orange stipe covered with brown granules, subglobose to broadly ellipsoid basidiospores, an abundance of thin- to thick-walled cheilocystidia and pleurocystidia, a trichohymeniderm pileipellis, and brown caulocystidia in clusters. Pluteus saisamorniae is a member of Pluteus sect. Hispidoderma. Additionally, P. losulus and P. septocystidiatus were discovered in Thailand for the first time and they belong to Pluteus sect. Pluteus. Comprehensive descriptions along with illustrations, photographs, phylogenetic trees showing their positions, and a comparison with phenetically similar taxa are provided. [ABSTRACT FROM AUTHOR]

A significant global problem affecting muskmelon ( Cucumis melo L.) is fruit rot caused by phytopathogenic fungi, which results in unsaleable products and substantial financial losses. In 2022 and 2023, fruit rot on muskmelon was found during the postharvest storage period in Phayao Province of northern Thailand. The aim of the current study was to isolate the species of fungi causing the fruit rot lesions. Out of the rot lesions on muskmelons, nine fungal isolates were received. All isolates of fungi were identified through a combination of morphological characteristics and molecular analyses. Based on their morphological traits, all isolated fungal isolate was assigned to the genus Fusarium . All the fungal isolates were determined to belong to the Fusarium incarnatum-equiseti species complex through multi-gene phylogenetic analysis employing the calmodulin ( cam ), RNA polymerase second largest subunit ( rpb2 ), and translation elongation factor 1-alpha ( tef1-α ) genes. These isolates were identified as F. compactum (SDBR-CMU483), F. jinanense (SDBR-CMU484, SDBR-CMU485, and SDBR-CMU486), F. mianyangense (SDBR-CMU487 and SDBR-CMU488), and F. sulawesiense (SDBR-CMU489, SDBR-CMU490, and SDBR-CMU491). Moreover, pathogenicity tests were subsequently carried out, and the results indicated that all fungal isolates caused symptoms of fruit rot on inoculated muskmelon fruits. Notably, this result was consistent with the symptoms observed throughout the postharvest storage period. In the fungicide screening test, all fungal isolates showed sensitivity to copper oxychloride. However, all isolates showed insensitivity to benalaxyl-M + mancozeb, carbendazim, mancozeb, and metalaxy. To the best of our knowledge, the present study is the first to identify F. compactum , F. jinanense , and F. mianyangense as new causative agents of muskmelon fruit rot in Thailand and other regions globally. This is also the first report of postharvest fruit rot on muskmelons caused by F. sulawesiense in Thailand. Furthermore, the fungicide screening results indicate that fungicide resistance can be beneficial in developing potential management strategies against postharvest fruit rot disease of muskmelon caused by these four pathogenic Fusarium species., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Suwannarach, Khuna, Thitla, Senwanna, Nuangmek, Kumla and Lumyong.)

Jackfruit (Artocarpus heterophyllus Lam.) is commonly grown in Thailand. In June 2023, leaf anthracnose on this plant was observed at a field in Chai Prakan District (19°42'24"N, 99°01'59"E), Chiang Mai Province, Thailand, with ~25% disease incidence in a 1000-m2 plantation area. The initial symptom had brown spots with a yellow halo, enlarged, elongated, 0.2 to 2 cm in diameter, irregular, sunken, brown, with a dark brown halo, and leaves withered and dried. Pale yellow conidiomata developed on the lesions in high humidity. Ten symptomatic leaves were used to isolate the fungal causal agents through a single spore isolation method (Tovar-Pedraza et al. 2020). Four fungal isolates (SDBR-CMU492 to SDBR-CMU495) with similar morphology were obtained. Colonies on potato dextrose agar (PDA) were 70 to 85 mm in diameter, white to grayish white with cottony mycelia, the reverse pale yellow after incubation at 25°C for 1 week. All isolates produced asexual structures. Setae were brown with 1 to 3 septa, 40 to 100 × 2.2 to 4.0 µm, a cylindrical base, and acuminate tip. Conidiophores were hyaline to pale brown, septate, and branched. Conidiogenous cells were hyaline to pale brown, cylindrical to ampulliform, 7.4 to 27.2 × 2.0 to 4.5 µm. Conidia were one celled, hyaline, smooth walled, cylindrical, ends rounded, guttulate, 11.1 to 15.7 × 3.4 to 6.1 µm. Appressoria were dark brown to black, oval to irregular, 8.8 to 24.9 × 3.6 to 10 µm. Morphologically, all isolates resembled the Colletotrichum gloeosporioides species complex (Weir et al. 2012). The internal transcribed spacer (ITS) region, actin (act), β-tubulin (tub2), calmodulin (CAL), and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) genes were amplified using primer pairs ITS5/ITS4, ACT-512F/ACT-783R, T1/T22, CL1C/CL2C, and GDF1/GDR1, respectively (White et al. 1990; Weir et al. 2012). Sequences were deposited in GenBank (ITS: PP068858, PP068859, PP446789, PP446790; act: PP079636, PP079637, PP460760, PP460761; tub2: PP079638, PP079639, PP460762, PP460763; CAL: PP079634, PP079635, PP460758, PP460759; GAPDH: PP079632, PP079633, PP460756, PP460757). Maximum likelihood phylogenetic analyses of the concatenated five genes identified all isolates as C. siamense. To pathogenicity test, the mature leaves of a healthy plant were surface disinfested using 0.1% NaClO for 3 min, rinsed three times with sterile water, and wounded. Conidia suspensions (15 µl of 1 × 106 conidia/ml) of each isolate grown on PDA at 25°C for 2 weeks were used to inoculate wounded and unwounded samples by the attached method. Control leaves were mock inoculated with sterile distilled water. Ten replications were conducted for each treatment and repeated twice. Plants were placed in a greenhouse at 25 to 30°C and 80 to 90% relative humidity. After 7 days, all inoculated leaves displayed brown lesions, while control leaves had no symptoms. Colletotrichum siamense was reisolated from inoculated tissues on PDA to complete Koch's postulates. Prior to this study, C. fructicola and C. gloeosporioides caused leaf anthracnose on jackfruit worldwide (Sangchote et al. 2003; Chitambar 2016). Leaf anthracnose on jackfruit caused by C. siamense has been reported from Australia (James et al. 2014) and Bazil (Borges et al. 2023). In Thailand, Bhunjun et al. (2019) reported that C. artocarpicola causes leaf anthracnose in jackfruit. Therefore, this is first report of C. siamense causing leaf anthracnose on jackfruit in Thailand. The finding will inform epidemiological investigations and future approaches to managing this disease.

Guava (Psidium guajava L.) is a popular fruit crop that is widely cultivated in Thailand. In November 2023, brown spot disease on guava was observed during postharvest storage at 22 to 31°C and 70 to 75% relative humidity over a period of 3 to 7 days in Fang District, Chiang Mai Province, Thailand. The disease incidence was ~20% of 100 fruits per pallet box. The disease severity on each fruit ranged from 40 to 70% of the surface area affected by lesions. The symptoms appeared as circular to irregular brown to dark brown spots, ranging from 5 to 30 mm in diameter. Fungi were isolated from lesions using a single conidial isolation method (Choi et al. 1999). Two fungal isolates (SDBR-CMU497 and SDBR-CMU498) with similar morphology were obtained. Colonies on potato dextrose agar (PDA) and malt extract agar (MEA) were 65 to 67 and 29 to 38 mm in diameter, respectively after incubation for 1 week at 25°C. Colonies on PDA and MEA were flat, slightly undulate, greenish gray in the center, greyish green at the margin; reverse black. Both isolates produced asexual structures. Pycnidia were black, granular, and grouped. Conidiogenous cells were hyaline, subcylindrical to cylindrical, 8.5 to 17.5 × 3 to 5.5 µm. Conidia were single-celled, hyaline, obovoid to ellipsoid, 5.2 to 9.4 × 3.6 to 7.5 µm (n = 50), smooth-walled, with a single apical appendage. Morphologically, both isolates resembled Phyllosticta capitalensis (Wikee et al. 2013). The internal transcribed spacer (ITS) region, large subunit (nrLSU), translation elongation factor 1-alpha (tef1-α), actin (act), and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) genes were amplified using primer pairs ITS5/ITS4, LROR/LRO5, EF1-728F/EF2, ACT-512F/ACT-783R, and GPD1-LM/GPD2-LM, respectively (White et al. 1990; Zhang et al. 2022). Sequences were deposited in GenBank (ITS: PP946770, PP946771; nrLSU: PP948677, PP948678; tef1-α: PP948012, PP948013; act: PP948014, PP948015; GAPDH: PP948016, PP948017). Maximum likelihood phylogenetic analyses of the concatenated five genes identified both isolates as P. capitalensis. Thus, both morphology and molecular data confirmed the fungus as P. capitalensis. To confirm pathogenicity, healthy commercial guava fruits cultivar Kim Ju were surface disinfected by 0.1% NaClO for 3 min, rinsed three times with sterile distilled water, and wounded (Cruz-Lagunas et al. 2023). Conidia were collected from 2-week-old cultures on PDA and suspended in sterile distilled water. Fifteen microliters of a 1 × 106 conidia/ml suspension were dropped onto the wounded fruits. Mock inoculations were used as a control with sterile distilled water. Ten replications were conducted for each treatment and repeated twice. The inoculated fruits were stored in individual sterile plastic boxes at 25°C with 80 to 90% relative humidity. After 7 days, all inoculated fruits exhibited brown to dark brown lesions, while control fruits were asymptomatic. Phyllosticta capitalensis was consistently reisolated from the inoculated tissues on PDA to complete Koch's postulates. Prior to this study, P. capitalensis was known to cause brown or black spot disease on guava fruits cultivated in fields in China (Liao et al. 2020), Egypt (Arafat 2018), and Mexico (Cruz-Lagunas et al. 2023). To our knowledge, this is the first report of P. capitalensis causing postharvest brown spot disease on guava fruit in Thailand. The results will inform epidemiological investigations and future approaches to managing this disease.

Most species of Dothiora are known from the dead parts of various host plants as saprobic fungi in terrestrial habitats occurring in tropical and temperate regions. In the present study, samples of Dothiora were collected from dead twigs and branches of Capparis spinosa , Rhaponticum repens , and an unknown angiosperm plant from the Tashkent and Jizzakh regions of Uzbekistan. Multi-gene phylogenetic analyses based on a combined ITS, LSU, SSU, TEF1 , and TUB2 sequence data revealed their taxonomic positions within the Dothideaceae. Three new species of Dothiora , namely, Dothiora capparis , Dothiora rhapontici , and Dothiora uzbekistanica were proposed by molecular and morphological data. Likewise, the phylogenetic relationship and morphology of Dothiora are discussed. In addition, we provide a list of accepted Dothiora species, including host information, distribution, morphology descriptions, and availability of sequence data, to enhance the current knowledge of the diversity within Dothiora ., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author SH declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2024 Senwanna, Hongsanan, Khuna, Kumla, Yarasheva, Gafforov, Abdurazakov and Suwannarach.)

A new species of soil fungi, described herein as Apophysomycesthailandensis , was isolated from soil in Chiang Mai Province, Thailand. Morphologically, this species was distinguished from previously described Apophysomyces species by its narrower trapezoidal sporangiospores. A physiological determination showed that A.thailandensis differs from other Apophysomyces species by its assimilation of D-turanose, D-tagatose, D-fucose, L-fucose, and nitrite. A phylogenetic analysis, performed using combined internal transcribed spacers (ITS), the large subunit (LSU) of ribosomal DNA (rDNA) regions, and a part of the histone 3 (H3) gene, lends support to our the finding that A.thailandensis is distinct from other Apophysomyces species. The genetic distance analysis of the ITS sequence supports A.thailandensis as a new fungal species. A full description, illustrations, phylogenetic tree, and taxonomic key to the new species are provided. Its metal minerals solubilization ability is reported.