Draft Genome Sequence of a New Fusarium Isolate Belonging to Fusarium tricinctum Species Complex Collected From Hazelnut in Central Italy

In summer 2019, during a survey on the health status of a hazelnut orchard located in the Tuscia area (the province of Viterbo, Latium, Italy), nuts showing symptoms, such as brown-grayish spots at the bottom of the nuts progressing upward to the apex, and necrotic patches on the bracts and, sometimes, on the petioles, were found and collected for further studies. This syndrome is associated with the nut gray necrosis (NGN), whose main causal agent is Fusarium lateritium. Aiming to increase knowledge about this fungal pathogen, the whole-genome sequencing of a strain isolated from symptomatic hazelnut was performed using long Nanopore reads technology in combination with the higher precision of the Illumina reads, generating a high-quality genome assembly. The following phylogenetic and comparative genomics analysis suggested that this isolate is caused by the F. tricinctum species complex rather than F. lateritium one, as initially hypothesized. Thus, this study demonstrates that different Fusarium species can infect Corylus avellana producing the same symptomatology. In addition, it sheds light onto the genetic features of the pathogen in subject, clarifying facets about its biology, epidemiology, infection mechanisms, and host spectrum, with the future objective to develop specific and efficient control strategies.

Fungi Detected in the Previous Year’s Leaf Petioles of Fraxinus excelsior and Their Antagonistic Potential against Hymenoscyphus fraxineus

Studies on fungal communities in the previous year’s leaf petioles of Fraxinus excelsior found in litter in five ash stands in southern Poland were made in 2017. Fungi were identified on the basis of isolation from 300 surface sterilized leaf petioles and by in situ inventory of fruit bodies (on 600 petioles, in spring and autumn). Identification was based on morphology of colonies and fruit bodies, and sequencing of ITS region of the rRNA gene cluster. In total, 2832 isolates from 117 taxa (Ascomycota—100; Basidiomycota—15; Mucoromycota—2 taxa) were obtained with the isolation method. The most frequent taxa (with frequency >10%) were: Nemania serpens, Hymenoscyphus fraxineus, Alternaria sp. 1, Boeremia sp., Helotiales sp. 1, Epicoccum nigrum, Venturia fraxini, Fusarium sp., Fusarium lateritium, Nemania diffusa, Typhula sp. 2 (in descending order). In total, 45 taxa were detected with the in situ inventory method. Eleven taxa were classified as dominant: Hymenoscyphus fraxineus, Venturia fraxini, Leptosphaeria sp. 2, Cyathicula fraxinophila, Typhula sp. 2, Hypoderma rubi, Pyrenopeziza petiolaris, Cyathicula coronata, Hymenoscyphus scutula, Leptosphaeria sclerotioides and Hymenoscyphus caudatus. Among 202 leaf petioles colonized by H. fraxineus, 177 petioles also showed fructification of 26 other fungi. All the isolated saprotrophs were tested in dual-culture assay for antagonism to two strains of H. fraxineus. Three interaction types were observed: type A, mutual direct contact, when the two fungi meet along the contact line (occurred with 43.3% of test fungi); type B, with inhibition zone between colonies (with 46.9% of test fungi); type C, when the test fungus overgrows the colony of H. fraxineus (with 9.8% of test fungi). The possible contribution of the fungal saprotrophs in limiting of the expansion of H. fraxineus in ash leaf petioles, which may result in reduction in the inoculum of ash dieback causal agent, is discussed.

4,6′-Anhydrooxysporidinone from Fusarium lateritium SSF2 Induces Autophagic and Apoptosis Cell Death in MCF-7 Breast Cancer Cells

Previous studies have reported that 4,6′-Anhydrooxysporidinone (SSF2-2), isolated from Fusarium lateritium SSF2, has neuroprotective effects on the HT-22 hippocampal neuronal cell line. However, the anti-cancer effect of SSF2-2 remains unclear. Here, we examined the viability of MCF-7 human breast cancer cells treated with SSF2-2 or left untreated using a cell viability assay kit. The underlying molecular mechanism was further investigated by Western blotting and immunocytochemistry studies. The results demonstrated that SSF2-2 inhibited the viability of MCF-7 cells. Treatment with SSF2-2 increased the levels of cleaved caspase-9, cleaved caspase-7, poly (ADP-ribose) polymerase (PARP), and LC3B. Additionally, SSF2-2 significantly increased the conversion of LC3-I to LC3II and LC3-positive puncta in MCF-7 cells.

NGHIÊN CỨU KHẢ NĂNG ỨC CHẾ NẤM FUSARIUM DECEMCELLULARE VÀ FUSARIUM LATERITIUM GÂY BỆNH LOÉT THÂN, CÀNH SƯA CỦA VI KHUẨN NỘI SINH

Cây Sưa (Dalbergia tonkinensis Prain) là loài cây gỗ quý, hiếm, có giá trị kinh tế cao ở Việt Nam. Hoạt động gây trồng Sưa trong những năm vừa qua khá sôi động nhưng chủ yếu là nguồn giống trôi nổi và chất lượng cây giống không cao. Những năm gần đây, rừng trồng Sưa tập trung và cây con thường bị nấm Fusarium decemcellulare và F. lateritium gây bệnh loét thân cành gây ảnh hưởng sinh trưởng và chất lượng của cây. Nhằm mục đích phát triển chế phẩm sinh học phòng trừ bệnh, nghiên cứu này đã phân lập, thuần khiết được 12 chủng vi khuẩn nội sinh từ các mẫu cành tươi của 15 cây Sưa khảo nghiệm tại Phú Thọ. Đánh giá hiệu lực ức chế nấm Fusarium decemcellulare và F. lateritium gây bệnh loét thân cành của các chủng vi khuẩn nội sinh đã xác định được 2 chủng vi khuẩn (KD6.3 và KD5.3) có khả năng ức chế mạnh đối với nấm F. decemcellulare và 2 chủng (KD6.3 và KD2.1) ức chế trung bình đối với nấm F. lateritium. Kết quả nghiên cứu này cho thấy có thể sử dụng 3 chủng vi khuẩn nội sinh (KD6.3, KD5.3 và KD2.1) để tiếp tục nghiên cứu tạo chế phẩm sinh học phòng trừ bệnh loét thân cành cho cây Sưa.

Neuroprotective Effect of Tricyclic Pyridine Alkaloids from Fusarium lateritium SSF2, against Glutamate-Induced Oxidative Stress and Apoptosis in the HT22 Hippocampal Neuronal Cell Line

Excessive glutamate damages neuronal cells via the accumulation of intracellular reactive oxygen species (ROS), calcium ion (Ca2+) influx, depolarization of mitochondrial membrane potential, and apoptosis, which may result in the development of chronic neurodegenerative diseases. In this study, we evaluated the effects of 4,6′-anhydrooxysporidinone isolated from endophytic fungus Fusarium lateritium SSF2 on glutamate-induced cytotoxicity, accumulation of intracellular ROS, increases in superoxide anion production, Ca2+, depolarization of mitochondrial membrane potential, and apoptotic cell death in hippocampal HT22 cells. 2′,7′-Dichlorofluorescin diacetate (H2DCFDA) staining was used to determine the intracellular reactive oxygen species concentration and dihydroethidine (DHE) staining was used to determine the superoxide radical. Expression of the nuclear factor-erythroid-2–related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) was analyzed by Western blot. Fluo-4 staining was used to determine the intracellular Ca2+ levels. In order to explore mitochondrial membrane potential, tetramethylrhodamine methyl ester (TMRM) staining was used. Apoptotic cell death was evaluated using Annexin-V/propidium iodide (PI) staining and TUNEL staining. Expression of the cytochrome c release and cleaved caspase-9, -3 was analyzed by Western blot. Here, we were able to isolate 4,6′-anhydrooxysporidinone from endophytic fungus, Fusarium lateritium SSF2, which was shown to protect HT22 cells from glutamate-induced cytotoxicity, accumulation of intracellular ROS, increases in superoxide anion production, Ca2+, and depolarization of mitochondrial membrane potential. In addition, 4,6′-anhydrooxysporidinone enhanced the expressions of Nrf2 and HO-1. It also inhibited the apoptotic cell death through the inhibition of cytochrome c release and cleaved caspase-9, -3 in glutamate-treated HT22 cells. Therefore, our results provide ample evidence of the neuroprotective properties of 4,6′-anhydrooxysporidinone.

Состав энтомопатогенных видов гифальных грибов с пораженных гусениц хлопковой совки

В статье обсуждаются вопрос поиска энтомопатогенных грибов, выявленных с пораженных гусениц хлопковой совки на посевах хлопчатника и овощных культур. В результате выделено 20 видов энтомопатогенных гифальных микромицетов из 12 родов, 3 семейств грибов. Была проверена вирулентность выявленной микобиоты. Из представленных данных следует, что процент поражения гусениц восковой моли в опыте при искусственном заражении колеблется в пределах от 2 до 25%. Отмечено, что гибель гусениц в течение 20 дней отмечалась лишь в случае со штаммами видов Aspergillus fumigates (4% гусениц погибли), Aspergillus flavus, Trichotecium roseum, Spicaria heliothis и Fusarium lateritium вызвали гибель 2% гусениц. На основании полученных данных был сделан вывод, что выявленные виды в той или иной степени обладают определенными энтомопатогенными свойствами, но данные штаммы ввиду слабой вирулентности для насекомых не могут быть примененными в практических целях.

Состав энтомопатогенных видов гифальных грибов с пораженных гусениц хлопковой совки

В статье обсуждаются вопрос поиска энтомопатогенных грибов, выявленных с пораженных гусениц хлопковой совки на посевах хлопчатника и овощных культур. В результате выделено 20 видов энтомопатогенных гифальных микромицетов из 12 родов, 3 семейств грибов. Была проверена вирулентность выявленной микобиоты. Из представленных данных следует, что процент поражения гусениц восковой моли в опыте при искусственном заражении колеблется в пределах от 2 до 25%. Отмечено, что гибель гусениц в течение 20 дней отмечалась лишь в случае со штаммами видов Aspergillus fumigates (4% гусениц погибли), Aspergillus flavus, Trichotecium roseum, Spicaria heliothis и Fusarium lateritium вызвали гибель 2% гусениц. На основании полученных данных был сделан вывод, что выявленные виды в той или иной степени обладают определенными энтомопатогенными свойствами, но данные штаммы ввиду слабой вирулентности для насекомых не могут быть примененными в практических целях.