A new phenylspirodrimane derivative from the deep-sea-derived fungus Stachybotrys chartarum FS705.

A new phenylspirodrimane derivative named stachybotrysin A (1), together with four known analogues (2-5) were isolated and purified from the solid culture of the deep-sea-derived Stachybotrys chartarum FS705. Their structures were determined by comprehensive spectroscopic analysis and the absolute configuration was evaluated by theoretical ECD calculations. Compounds 1-5 were evaluated for their cytotoxic, antibacterial and α-glucosidase inhibitory activities. The results showed that compound 2 displayed mild cytotoxicity with IC50 values in the range of 8.88 ∼ 22.73 µM against four human tumour cell lines, SF-268, MCF-7, HepG-2, and A549. Compound 1 showed strong α-glucosidase inhibitory activity with an IC50 value of 20.68 µM. Compounds 4 and 5 exhibited weak antibacterial activity against Bacillus subtilis.

Cytotoxic pyrone derivatives from the deep-sea-derived fungus Cladosporium halotolerans FS702.

Two new compounds (R)-6-((8S)-hydroxypropyl)-2-methyl-5,6-dihydro-4H-pyran-4-one (1) and (R)-6-((8R)-hydroxypropyl)-2-methyl-5,6-dihydro-4H-pyran-4-one (2), together with four known compounds were isolated from the marine-derived fungus Cladosporium halotolerans FS702. The structures of these compounds were determined on the basis of extensive spectroscopic analysis including 1D/2D NMR, IR, UV, HRESIMS, ECD calculations as well as the modified Mosher's method. Cytotoxic assay results showed that compound 2 had significant cytotoxic activity against SF-268, MCF-7, HepG-2, and A549 cells lines with IC50 values of 0.16, 0.47, 0.33 and 0.23 µM, respectively.

3-Carboxy-indole derivatives from the deep-sea-derived fungus Phomopsis tersa FS441.

Three new compounds phomtersines A-C (1-3) together with nine known compounds were isolated from the marine-derived fungus Phomopsis tersa FS441. Their structures were sufficiently established by spectroscopic methods, including extensive 1D and 2D NMR techniques and modified Snatzke's method. Moreover, compounds 1-12 were evaluated for cytotoxic and anti-inflammatory activities. As a result, phomtersine B (2) and the known compound 10 showed moderate cytotoxic activity against the four tested cell lines with IC50 values ranging from 20.21 to 36.53 µM, and phomtersine A (1) exhibited moderate inhibitory activity against LPS-induced NO production.

Cytospotones A-D, four new polyketones from the endophytic fungus Cytospora sp. A879.

Three new α-pyrone derivatives cytospotones A-C (1-3) and a new cyclohexenone derivative cytospotone D (4) together with four known α-pyrones were isolated from the endophytic fungus Cytospora sp. A879 of Pogostemon cablin (Blanco) Benth. The structures of 1-4 were elucidated primarily by spectroscopic methods (1D, 2D NMR and HRESIMS), ECD spectra analyses, and ECD calculations. Furthermore, the four new compounds (1-4) were evaluated for their anti-inflammatory and α-glucosidase inhibitory activities. The results showed that compound 1 had moderate inhibitory effect on LPS-induced NO production in RAW 264.7 macrophages.

First Report of Postharvest Fruit Rot of Loquat (Rhaphiolepis loquata) Caused by Ceratobasidium sp. in China.

Loquat, Rhaphiolepis loquata B.B.Liu & J.Wen (syn. Eriobotrya japonica) (Liu et al., 2020), is a subtropical evergreen fruit tree crop, for which China is the largest producer. Loquat fruit is favored by consumers for its attractive appearance, juicy taste, and rich nutrients (Tian et al., 2007). In May 2020, postharvest fruit rot was observed on loquat (about 10% of the fruits showed disease symptoms) in a local agricultural market (113°36'E, 23°11'N) of the Yuancun district in Guangzhou, China. The symptoms began with white mycelia above the epidermal surface of the fruits, then gradually developed into browning spots and soft lesions. To isolate and identify the pathogen, fruits (n=35) were surface disinfected by 1% NaOCl (1 min), 70% ethanol (30 s) and then washed twice with sterile distilled water and, thirty small pieces (3-5 mm2) were excised from the lesion margins. The excised tissue pieces were cultured on potato dextrose agar (PDA). After the colonies were established on PDA, the fungal strains were purified by the hyphal-tip method. Thirty-four fungal isolates were obtained from the infected isolation fruits (isolation frequency about 76%). Two morphologically similar isolates (PP-8 and PP-9) were used for further study. Fungal colonies were initially white, then turned brown with abundant aerial mycelia, and septate hyphae were 3.9 to 4.5 µm in diameter and branched at right angles with a constriction at the branch point. Binucleate cells were observed using safranin O-KOH solution stain and matched Ceratobasidium spp. (Binucleate Rhizoctonia spp.) morphological descriptions (Zhou et al. 2017). The molecular identity of the isolates was confirmed by sequencing the internal transcribed spacer (ITS) rDNA region and beta-tubulin (TUB) genes using the primer pairs ITS1/4 (White et al. 1990) and BT36F/BT12R, which were used for isolates belonging to the Rhizoctonia species complex (Thon and Royse 1999). BLASTN analysis of the two isolates sequences, which were deposited in GenBank (OP476745 and OP476746 for ITS; OR723969 and OR723968 for TUB), showed 95~97% identity with those of Ceratobasidium sp. (MT796446 and MF992150, DQ085499 and CP059650), respectively. The maximum-likelihood phylogenetic tree was analyzed based on the multiple-gene sequences of ITS and beta-tubulin sequences. The results showed that the isolates (PP-8 and PP-9) were confirmed as Ceratobasidium sp. Pathogenicity test was conducted on loquat. Six healthy fruits were inoculated with mycelial discs (5 mm in diameter) of the isolate after being wounded with a needle or unwounded. As negative control, six fruits were inoculated with PDA agar. All inoculated fruits were incubated in the dark at 26°C and 90% relative humidity for 7 days post inoculation. White mycelia were observed on the epidermal surface of both unwounded and wounded fruits, furthermore, the latter showed browning spots and rot lesions. Control fruits remained asymptomatic. Pathogenicity test was performed three times. The same fungal pathogen was re-isolated from inoculated fruits and identified by morphological observation and molecular analysis, thus confirming Koch's postulates. Ceratobasidium includes pathogens of members of the Annonaceae, Rosaceae, Rubiaceae, Rutaceae and Theaceae families, found in tropical agroecosystems in Africa, Asia and South America (Farr et al. 2022). To our knowledge, this is the first report of Ceratobasidium sp. causing postharvest fruit rot of loquat in China, further monitoring should be performed to quantify yield impacts and develop effective management strategies for this disease.

Anti-Inflammatory Phomalones from the Deep-Sea-Derived Fungus Trichobotrys effuse FS522.

Four new phomalones A-D (1-4), together with five known analogues (5-9) were isolated from the deep-sea-derived fungus Trichobotrys effuse FS522. Their structures of the new compounds established by analysis of their NMR and HR-ESI-MS spectroscopic data, and the absolute configurations of 2 was determined by electronic circular dichroism (ECD) calculations. compounds 4, 6 and 8 substantially inhibited the production of nitric oxide (NO) with IC50 values of 4.64, 13.90, and 34.07 µM.

Occurrence of Postharvest Fruit Rot of Mango Caused by Fusarium pernambucanum in China.

Mango (Mangifera indica L.) is one of the most important tropical fruits in the world, thanks to its pleasant taste, aroma and high nutritional value (Ibarra et al. 2015). In June 2021, Surveys were conducted in three agricultural markets (113°36'E, 23°11'N) of the Yuancun district in Guangzhou, China. Postharvest fruit rot was observed on mango (about 25% of the fruits showed disease symptoms). Black rot symptomatic lesions were observed on the fruit surface and eventually penetrated the mesocarp of mango fruits. To isolate and identify the pathogen, fruits (n=35) were surface disinfected with 1% NaOCl (1 min), 70% ethanol (30 s) and then washed twice with sterile distilled water. Thirty small pieces (3-5 mm2) were excised from the lesion margins. The excised tissue pieces were cultured on potato dextrose agar (PDA). Pure cultures were obtained by transferring hyphal tips onto fresh PDA. Fungal isolates XTM-5 and XTM-8 were isolated from diseased fruits. All isolates grown on PDA had abundant, fluffy, whitish to yellowish aerial mycelia, and the colony reverse was pale brown. Macroconidia were falcate, slightly curved with 5-7 septa, 29.5-42.2 × 4.3-6.2 µm. Spindle-shaped mesoconidia were abundantly produced, straight to slightly curved with 3-4 septa, 20.3-24.5 × 4.6-4.8 µm. Microconidia were pyriform to obovate with 0-2 septa, 7.3-11.7 × 2.4-3.2 µm. Chlamydospores were globose or irregular, in chains and, hyaline to light brown. Based on the morphological characteristics, the fungus was tentatively identified as Fusarium pernambucanum (Santos et al. 2019). The molecular identity of the isolates was confirmed by sequencing the internal transcribed spacer (ITS), translation elongation factor 1 alpha (TEF1) and RNA polymerase subunit II gene region (RPB2) genes (White et al. 1990; O'Donnell et al. 2022). Sequences of isolate XTM-8 were deposited in GenBank (ITS: ON413679.1, TEF1:ON420221.2, RPB2: ON420222.2). A maximum-likelihood phylogenetic tree based on the concatenated sequences confirmed the isolates as F. pernambucanum (Xia et al. 2019). A pathogenicity test was conducted on mango. Six healthy fruits were inoculated with F. pernambucanum mycelial discs (5 mm in diameter) after being wounded with a needle or unwounded, six control fruits were inoculated with PDA agar. All inoculated fruits were incubated in the dark at 26°C and 95% relative humidity for 7 days post inoculation. Control fruits remained asymptomatic, whereas inoculated fruit developed symptoms on the fruit surface at the point of inoculation. The pathogenicity test was performed three times. The original isolates were confirmed morphologically and molecularly after they were reisolated from the symptomatic fruit, thus confirming Koch's postulates. F. pernambucanum is a widespread pathogen that causes diseases across a wide range of plant hosts in China, such as muskmelon fruit rot (Zhang et al. 2022); mango leaf spots (Guo et al. 2021) and plum leaf blight (Lu et al. 2022). To our knowledge, this is the first report of F. pernambucanum causing fruit rot of mango in China. As mango contamination with Fusarium mycotoxins poses a health risk for consumers, the occurrence of this disease needs to be carefully monitored to ensure effective disease management strategies are implemented in mango production.

Enhancing gliotoxins production in deep-sea derived fungus Dichotomocyes cejpii by engineering the biosynthetic pathway.

Gliotoxin can be developed as potent biopesticide. In this study, the positive transcriptional factor gliZ, glutathione-S transferase encoding gene gliG and gliN were firstly deleted by CRISPR/Cas9 system, which abolished the production of gliotoxin-like compounds in Dichotomomyces cejpii. CRISPR/dCas9 system targeting promoter of gliG was used to activate the biosynthetic genes in gli cluster. The overexpression of gliZ, gliN and gliG can significantly improve the yield of gliotoxin-like compunds. The gliotoxin yields was improved by 16.38 ± 1.36 fold, 18.98 ± 1.28 fold through gliZ overexpression and gliM deletion in D. cejpii FS110. In addtion, gliN was heterologously expressed in E. coli, the purified GliN can catalyze gliotoxin into methyl-gliotoxin. Furthermore, the binding sequences of GliZ in the promoters of gliG was determined by Dnase footprinting. This study firstly illustrated the transcriptional regulatory mechanism of DcGliZ for the gliotoxin biosynthesis in D. cejpii, and improved the yields of gliotoxins significantly in D. cejpii via biosynthetic approaches.

Potential Anti-Candida albicans Mechanism of Trichoderma Acid from Trichoderma spirale.

Candida albicans is the main causal pathogen of fungal infections in human beings. Although diverse anti-C. albicans drugs have been explored, the drug resistance and side effects of these drugs are intensifying. Thus, it is urgent to explore new anti-C. albicans compounds from natural products. In this study, we identified trichoderma acid (TA), a compound from Trichoderma spirale with a strong inhibitory effect on C. albicans. Transcriptomic and iTRAQ-based proteomic analyses of TA-treated C. albicans in combination with scanning electronic microscopy and reactive oxygen species (ROS) detection were performed to investigate the potential targets of TA. The most significant differentially expressed genes and proteins after TA treatment were verified through Western blot analysis. Our results revealed that mitochondrial membrane potential, endoplasmic reticulum, ribosomes in the mitochondria, and cell walls were disrupted in TA-treated C. albicans, leading to the accumulation of ROS. The impaired enzymatic activities of superoxide dismutase further contributed to the increase in ROS concentration. The high concentration of ROS led to DNA damage and cell skeleton destruction. The expression levels of Rho-related GTP-binding protein RhoE (RND3), asparagine synthetase (ASNS), glutathione S-transferase, and heat shock protein 70 were significantly up-regulated in response to apoptosis and toxin stimulation. These findings suggest that RND3, ASNS, and supereoxide dismutase 5 are the potential targets of TA, as further demonstrated through Western blot analysis. The combination of transcriptomic, proteomic, and cellular analyses would provide clues for the anti-C. albicans mechanism of TA and the defensive response mechanism of C. albicans. TA is thus recognized as a promising new anti-C. albicans leading compound that alleviates the hazard of C. albicans infection in human beings.

Secondary metabolites from a deep-sea derived fungal strain of Phomopsis lithocarpus FS508.

One new isoindolinone lactam lithocarlactam A (1) and one new triterpene lithocarin D (2), along with nine known natural products (3-11) were isolated from the broth extract of marine fungus Phomopsis lithocarpus FS508, which was isolated from a deep-sea sediment sample. Their structures were elucidated by interpretation of spectroscopic analysis and comparison with previously published literatures for the known compounds. Moreover, compounds 1 and 2 were evaluated for cytotoxic activity against SF-268, MCF-7, HepG-2, and A549 cell lines. However, both of them showed no activity against the tumor cell lines.

The Improvement of Epothilone D Yield by the Disruption of epoK Gene in Sorangium cellulosum Using TALEN System.

Epothilones are a kind of 16-member macrolides with strong anticancer activity, which was produced by Sorangium cellulosum. Epothlione D shows better drug resistance and safety than taxol in clinical trials. However, the low yield of epothilone D in Sorangium cellulosum and thereof toxicity limited the application of epothilone D. In this study, the epoK gene in gene cluster for epothilone was firstly inactivated by the employment of TALEN gene knockout system. The qRT-PCR analysis and sequencing were performed to confirm the gene deletion of epoK, resulting in the epothilone D yield improvement by 34.9±1.6% and the decrease of epothilone B yield by 34.2±2.5%, which was demonstrated by LC-MS analysis. This study would lay a foundation for the yield improvement of epothilones D, B and thereof derivatives in S. cellulosum by genetic engineering, thus promoting the applications of epothilones in the field of anticancer.

Post-harvest Anthracnose of Carambola (Averrhoa carambola) Caused by Colletotrichum fructicola in China.

Carambola (star fruit), a popular fruit of Averrhoa carambola in many parts of the world, is considered to have many beneficial nutritional and medicinal effects (Lakmal, K., et al,2021). In March 2020, anthracnose disease was observed on carambola (about 15% of the fruit showed similar symptoms) in multiple local agricultural markets (113°36'E, 23°11'N) of the Yuancun district in Guangzhou, China. Initial symptoms of infected fruit samples appeared as water-soaked, brown lesions. As the disease progressed, numerous acervuli appeared on fruit surfaces. Salmon-colored spore masses were observed on some fruit. To isolate and identify the pathogen, small pieces (3-5 mm2) were excised from the lesion margins of the fruit, which were surface disinfested by 1% NaOCl (60 s), 70% ethanol (30 s) and then washed twice with sterile distilled water. After surface disinfestation, the tissues were cultured on potato dextrose agar (PDA). Pure cultures were obtained by transferring hyphal tips onto fresh PDA. Fungal isolates (YT-5/6/9) were obtained and the strain YT-5 was selected for further study. The colony of strain YT-5 grown on PDA for 7 days appeared to be cottony, white to pale gray with the presence of multiple masses of conidia. Conidia 13.5-20 × 4.8-6.5 µm (n = 50), hyaline, aseptate, straight and cylindrical with rounded ends. Perithecia were thick-walled and globose with a prominent, narrow neck. Asci 37.1-60.2 × 7.1-11.3 µm (n = 25), 4-8 spored, clavate to cymbiform. Ascospores 7.1-17.2 × 4.5-6.5 µm (n = 35), hyaline, large guttulate at the center, slightly curved with rounded ends. Based on the morphological characteristics, the strain was identified as Colletotrichum fructicola (Prihastuti et al. 2009). The molecular identity of the isolates was confirmed by sequencing the internal transcribed spacer (ITS) rDNA region, chitin synthase (CHS-1), actin (ACT), glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and beta-tubulin (TUB2) genes (Prihastuti et al. 2009, Weir et al. 2012). BLASTN analysis of isolate YT-5 sequences, which were deposited in GenBank (ON428449, ON462353, ON886225, ON886224, ON462354) showed 100% identity with those of Colletotrichum fructicola (MW513778.1, MT918417.1, MW426526.1, MN525875.1, MT941526.1), respectively. A phylogenetic tree analysis based on the concatenated sequences confirmed the isolate YT-5 as C. fructicola. Pathogenicity tests were conducted on fresh fruit of carambola with the isolate YT-5. Healthy fruit was surface disinfested and inoculated with 5 mm mycelial discs of the strain YT-5 after being wounded with a needle or unwounded. Control fruit was inoculated with sterilized PDA plugs. All inoculated fruit was incubated at 26°C for 10 days post inoculation. Control fruit remained asymptomatic, whereas inoculated fruit developed symptomatic at the point of inoculation. The pathogenicity test was performed in duplicate. The pathogenic isolate of C. fructicola was successfully re-isolated on PDA from the symptomatic fruit, thus confirming Koch's postulates. C. fructicola has also been reported as a dominant and aggressive causal agent of anthracnose on sandy pear and avocado in China (Zhang et al. 2015; Li et al. 2022). To our knowledge, this is the first study to isolate and characterize C. fructicola causing carambola anthracnose and evaluate its pathogenicity in China, which will provide a better strategy for accurate diagnosis and effective management of anthracnose disease on carambola. References: Lakmal, K., et al. 2021. Food Sci Nutr 9.3. Prihastuti, H., et al. 2009. Fungal Divers. 39:89. Weir, B. S., et al. 2012. Stud Mycol. 73:115-180. Zhang P.F., et al. 2015. Eur J Plant Pathol.143:651-662. Li S.N., et al. 2022. Plant Dis. The authors declare no conflict of interest. Keywords: Anthracnose, Colletotrichum fructicola, carambola, China.

Neocucurbols A-H, Phomactin Diterpene Derivatives from the Marine-Derived Fungus Neocucurbitaria unguis-hominis FS685.

Neocucurbols A-D (1-4) are diterpene derivatives that possess a complex 6/6/5/5/6 polycyclic ring system with a characteristic tetrahedrofuran bridge ring skeleton. Neocucurbols E-H (5-8) are diterpenes that feature a 6/8/6 tricyclic ring system. Their structures were unambiguously determined by detailed spectroscopic analyses, X-ray diffractions studies, and ECD calculations. All compounds (1-8) were evaluated for in vitro antimicrobial and cytotoxic activities.

First Report of Postharvest Stem End Rot of mango Fruit (Mangifera indica) Caused by Diaporthe pseudomangiferae in China.

Mango (Mangifera indica L.) is considered one of the most important tropical or subtropical fruit crops (Nelson et al.2008). China is the second-largest producer of mango (Kuhn et al. 2017). In June 2021, postharvest stem-end rot disease was observed on Narcissus mango (about 20% of the fruits showed similar symptoms of infections) in local agricultural market of Guangzhou, China. Black rot symptomatic lesions were observed on the fruit surface, which initially started from the stem end and progresses into decay, turning brown. To isolate and identify the pathogen, small pieces (3-5 mm2) were excised from the lesion margins of the fruits (n=54), which were surface sterilized by 1% NaOCl (1 min), 70% ethanol (30 s) and then washed twice with sterile distilled water. After sterilization, the tissues were cultured on potato dextrose agar (PDA). Three morphologically similar isolates (SXM-1/2/3) were obtained and the representative isolate SXM-1 was analyzed. Colonies surface initially had white-gray moderate aerial mycelia, in reverse umber with patches of pale luteous to luteous. On malt extract agar (MEA) surface dirty white, reverse greyish sepia with patches of sienna. Conidiomata pycnidia, black, erumpent to superficial on PDA, globose with neck, ostiole exuding cream conidial droplets; Conidiophores hyaline, smooth, 1-3-septate, branched, densely aggregated, cylindrical, straight to sinuous, 22-42 × 2.8-3.7 µm. Alpha conidia (n = 50) aseptate, hyaline, smooth, fusiform to somewhat short cylindrical, 3.2-11 ×1.3-3.5 µm. Beta conidia (n = 30) hyaline, smooth, curved or hamate 14.8-33.6 × 1.1-2.6 µm. According to morphological characterization, the representative isolate SXM-1 was similar to Diaporthe pseudomangiferae CBS 101339 (Gomes et al. 2013). For molecular identification, the internal transcribed spacer (ITS) region, histone H3 (HIS) and ß-tubulin (TUB) genes (White et al. 1990; Carbone et al. 1999; Glass et al.1995) were amplified and sequenced, which were deposited in GenBank (ON243823, ON254656, ON254655). BLASTN analysis revealed that DNA sequences of the isolates (SXM-1/2/3) showed 99% identity with those of D. pseudomangiferae (MG576128.1, KC344149, MN329124.1), respectively. A phylogenetic tree analysis based on the concatenated sequences confirmed the isolates as D. pseudomangiferae. Pathogenicity tests were made with the representative isolate SXM-1. Healthy fruits were inoculated with 5 mm mycelial discs of the representative isolate SXM-1 after being wounded with a needle or non-wounded, control fruits were inoculated with sterilized PDA plugs. All inoculated and control fruits were incubated in the dark at 26°C for 7 days post-inoculation. Control fruits remained asymptomatic, whereas inoculated fruits were dark brown necrotic lesions with a roughly circular shape around the inoculation sites. Pathogenicity tests were performed in triplicate. The pathogenic isolates were successfully reisolated, thus confirming Koch's postulates. D. pseudomangiferae was associated with fruit peel of mango in Mexico and the Dominican Republic, and it has also been reported to cause inflorescence rot, rachis canker, and flower abortion in mango (Gomes et al. 2013; Serratodiaz et al. 2014). To our knowledge, this is the first report of D. pseudomangiferae causing postharvest stem-end rot of mango fruits in China. This finding suggests that D. pseudomangiferae is a potential problem for mango fruit production in China, and it is important to establish an adequate and effective control management of this disease. References: Nelson, S. C. 2008.Mango Anthracnose (Colletotrichum gloeosporiodes). Publication PD-48. Cooperative Extension Service, College of Tropical Agriculture and Human Resources, University of Hawai'i at Manoa, U.S.A. Kuhn, D. N., et al. 2017. Front. Plant Sci. 8:577. White, T. J., et al. 1990. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego. Carbone, I., et al. 1999. Mycologia. 91:553. Glass, N. L., et al. 1995. Appl. Environ. Gomes R. R., et al. 2013. Persoonia. 1:31. Serratodiaz, L. M., et al. 2014. Plant Dis. 98:1004. * These authors contributed equally to this work and should be considered co-first authors. The authors declare no conflict of interest. Keywords: Stem-end rot, Diaporthe pseudomangiferae, Mango, China.

Neocucurbins A-G, novel macrocyclic diterpenes and their derivatives from Neocucurbitaria unguis-hominis FS685.

Three novel phomactin diterpenes neocucurbins A-C (1-3) and their derivatives, neocucurbins D-G (4-7), were isolated from the marine-derived fungus Neocucurbitaria unguis-hominis FS685. Among them, neocucurbins A-C represent the first examples of the phomactin family with an unprecedented skeleton sharing a novel polyoxygen-hetero 5/6/12 or 5/6/13 fused tricyclic ring system; whereas neocucurbins D-G feature a 5/6 fused bicyclic ring system with the opening of the macrocyclic ring, which was found in the phomactin family for the first time. Moreover, spectroscopic data analyses, single-crystal X-ray diffraction experiments, and ECD calculations were conducted to illustrate the absolute configurations of their structures. Furthermore, all seven compounds (1-7) were evaluated for their cytotoxic and antimicrobial activities.

First Report of Anthracnose Disease on avocado (Persea americana) caused by Colletotrichum fructicola in China.

In September 2019, anthracnose-like symptoms were observed on fresh avocado fruits cv. "Hass", which were imported from Peru (Mission Produce, Inc.) and purchased at Ganfuyuan store, Guangzhou, China. After being stored for 5 days at room temperature, initial black specks developed into larger brown or black lesions on fruits, and salmon-colored conidial mass in the lesions were observed. To isolate and identify the pathogen, small pieces (5 mm × 5 mm) were excised from the lesion margins of the fruits, which were surface sterilized by 1% NaOCl (1 min), 70% ethanol (30 s) and then washed twice with sterile distilled water (SDW). After sterilization, the tissues were cultured on Potato Dextrose Agar (PDA) to obtain the pure strain NYG. The colonies grown on PDA for 7 days appeared to be cottony, white to pale gray with the presence of a conidial mass. Conidia 11.7-19 × 3.6-6.4 µm (n = 50), hyaline, aseptate, straight and cylindrical with rounded ends, Appressoria 6.2-11.9 × 4.5 × 7.4 µm (n = 50), brown to dark brown in different shapes. Perithecia were thick-walled and globose with a prominent, narrow neck. Asci 31.5-55 × 6-12.5 µm (n = 15), 6-8 spored, clavate to cymbiform. Ascospores 5-18 × 4.5-6 µm (n = 25), hyaline, large guttulate at the centre, slightly curved, rounded ends. Based on the morphological characteristics, the strain NYG was identified as Colletotrichum fructicola (Prihastuti et al. 2009). The identity of the strain was confirmed by means of multi-locus gene sequencing. The genomic DNA was extracted using Ezup Column Fungi Genomic DNA Purification Kit (Sangon Biotech Co., Ltd., China). The internal transcribed spacer (ITS) rDNA region, actin (ACT), chitin synthase (CHS-1), calmodulin (CAL), glyceraldehyde-3-phosphate dehydrogenase (GAPDH) partial genes (Templeton et al. 1999, Carbone et al. 1999) were amplified and sequenced, which were deposited in GenBank (OL413493, OL517766, OL517768, OM141126, OL517767). BLASTN analysis revealed that DNA sequences of the isolate showed 100% identity with those of C. fructicola (MT476840.1, MK208862.1, MZ965245.1, JX009665.1, MN982434.1), respectively. A phylogenetic tree analysis based on the concatenated sequences confirmed the isolate as C. fructicola. Pathogenicity was tested by infecting the fresh healthy avocado fruits with the isolated strain NYG. The fruits were surface sterilized, three unwounded and wounded avocados fruits were respectively inoculated with 10 l of conidial suspension (1×106 conidia/ml) by the drop inoculation method. Control fruits were inoculated with SDW containing Tween 20 (1 µl/ml H2O), respectively. All inoculated fruits were incubated at 25°C in the dark. Anthracnose symptoms were observed on the wounded and unwounded fruits after 3 to 5 days post inoculation, respectively. No symptoms were observed in the control on both the wounded and unwounded fruits. The pathogenicity test was performed in duplicate. The inoculated fungus was reisolated from the infected fruits and confirmed as C. fructicola, thus confirming Koch's postulates. C. fructicola represents an important fungal pathogen in several plantations worldwide (Farr et al. 2020), for example, the avocado fruits in Mexico (Dionicio, et al. 2018) and New Zealand (Hofer et al. 2021). This is the first report of anthracnose caused by C. fructicola on imported avocado fruits in China. The results of this study can not only help establish effective quarantine measures against anthracnose disease for imported avocado fruits in China, but also provide important reference to prevent the spread of this disease on China's domestic avocados.

Indole diketopiperazine alkaloids from the deep-sea-derived fungus Aspergillus sp. FS445.

Twelve indole diketopiperazine alkaloids (1‒12) including four new ones aspechinulins A‒D (1, 3, 5 and 12) were isolated from the deep-sea-derived fungus Aspergillus sp. FS445. Their structures were elucidated through spectroscopic analysis and the absolute configurations were determined by analyzing the experimental ECD data as well as the quantum chemical calculations. Compounds 1, 3 and 5 represented the first examples of indole diketopiperazine derivatives constructing a C5 unit at 11-NH through an imide linkage. The NO production inhibitory activity of the isolated compounds was evaluated and compounds 2‒5, 7 and 9 exhibited potential inhibitory activities against NO production with the IC50 values in the range of 20 ∼ 90 µM.[Formula: see text].

Cytotoxic polyketides from the deep-sea-derived fungus Aspergillus fischeri FS452.

Six globoscin derivatives (1‒6) including two new ones fischerins A (1) and B (2) were isolated from the deep-sea-derived fungus Aspergillus fischeri FS452. Their structures were elucidated by comprehensive spectroscopic analysis and the absolute configurations were determined by the quantum chemical ECD calculations. The in vitro cytotoxicity assays indicated that fischerin B (2) exhibited potential activities against the four tested human cancer cell lines (SF-268, MCF-7, HepG-2 and A549) with the IC50 values in the range of 7-10 µM.

Bioactive polyketide derivatives from the endophytic fungus Phaeosphaeriopsis musa.

Two undescribed phenolic derivatives musaones A and B, six undescribed γ-butyrolactone musaolides A-F, together with two undescribed cyclopentanone musaolides G and H were isolated from the solid culture of an endophytic strain Phaeosphaeriopsis musae M. Arzanlou & Crous (Phaeosphaeriaceae). Their structures were unambiguously elucidated by extensive spectral analyses. The absolute configurations of two diastereomers musaolides G and H were assigned by comparing their experimental and calculated ECD data. Moreover, the in vitro α-glucosidase inhibition and cytotoxic activities of isolated compounds (except musaolide D) were evaluated to understand their biological effects, wherein musaone B and musaolide F displayed promising α-glucosidase inhibition with IC50 values of 37.3 ± 0.59 µM and 105.18 ± 2.76 µM respectively, compared to the positive control acarbose (24.99 ± 1.28 µM).