1
|
Khandekar SB, Fernandes RA. Asymmetric total syntheses of aspilactonol F and aspiketolactonol and synthetic studies toward diplofuranoxin. Org Biomol Chem 2024; 22:4508-4515. [PMID: 38747330 DOI: 10.1039/d4ob00549j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2024]
Abstract
The first asymmetric total synthesis of C9 polyketides, aspilactonol F and aspiketolactonol has been achieved. Ring-closing-metathesis has been employed as the key step in the synthesis. The total synthesis of aspilactonol F and aspiketolactonol was accomplished in 8 and 10 steps, in good overall yields of 28% and 24%, respectively, with only four column purifications for the former. A common strategy for the concise synthesis of the key intermediate of diplofuranoxin is also presented.
Collapse
Affiliation(s)
- Sagar B Khandekar
- Department of Chemistry, Indian Institute of Technology Bombay Powai, Mumbai 400076, Maharashtra, India.
| | - Rodney A Fernandes
- Department of Chemistry, Indian Institute of Technology Bombay Powai, Mumbai 400076, Maharashtra, India.
| |
Collapse
|
2
|
Phytophthora Species Involved in Alnus glutinosa Decline in Portugal. Pathogens 2023; 12:pathogens12020276. [PMID: 36839548 PMCID: PMC9966130 DOI: 10.3390/pathogens12020276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 02/02/2023] [Accepted: 02/06/2023] [Indexed: 02/10/2023] Open
Abstract
Recent field surveys conducted in five common alder ecosystems in Portugal have shown the occurrence of severe canopy dieback, bleeding canker and root rot symptoms indicative of Phytophthora infections. Isolations from symptomatic tissues, rhizosphere and water samples yielded a total of 13 Phytophthora species belonging to 6 phylogenetic clades, including P. lacustris (13 isolates), P. multivora (10), P. amnicola (9), P. chlamydospora (6), P. polonica (6), P. bilorbang (4), P. plurivora (4), P. cinnamomi (3), P. asparagi (2), P. cactorum (2), P. pseudocryptogea (2), P. gonapodyides (1) and P. rosacearum (1). Results of the pathogenicity test confirmed the complex aetiology of common alder decline and the additional risk posed by Phytophthora multivora to the riparian habitats in Portugal. At the same time, the diversity of Phytophthora assemblages detected among the investigated sites suggests that different species could contribute to causing the same symptoms on this host. Two species, P. amnicola and P. rosacearum, are reported here for the first time in natural ecosystems in Europe.
Collapse
|
3
|
Rathnayaka AR, Chethana KWT, Phillips AJL, Liu JK, Samarakoon MC, Jones EBG, Karunarathna SC, Zhao CL. Re-Evaluating Botryosphaeriales: Ancestral State Reconstructions of Selected Characters and Evolution of Nutritional Modes. J Fungi (Basel) 2023; 9:184. [PMID: 36836299 PMCID: PMC9961722 DOI: 10.3390/jof9020184] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 01/25/2023] [Accepted: 01/26/2023] [Indexed: 01/31/2023] Open
Abstract
Botryosphaeriales (Dothideomycetes, Ascomycota) occur in a wide range of habitats as endophytes, saprobes, and pathogens. The order Botryosphaeriales has not been subjected to evaluation since 2019 by Phillips and co-authors using phylogenetic and evolutionary analyses. Subsequently, many studies introduced novel taxa into the order and revised several families separately. In addition, no ancestral character studies have been conducted for this order. Therefore, in this study, we re-evaluated the character evolution and taxonomic placements of Botryosphaeriales species based on ancestral character evolution, divergence time estimation, and phylogenetic relationships, including all the novel taxa that have been introduced so far. Maximum likelihood, maximum parsimony, and Bayesian inference analyses were conducted on a combined LSU and ITS sequence alignment. Ancestral state reconstruction was carried out for conidial colour, septation, and nutritional mode. Divergence times estimates revealed that Botryosphaeriales originated around 109 Mya in the early epoch of the Cretaceous period. All six families in Botryosphaeriales evolved in the late epoch of the Cretaceous period (66-100 Mya), during which Angiosperms also appeared, rapidly diversified and became dominant on land. Families of Botryosphaeriales diversified during the Paleogene and Neogene periods in the Cenozoic era. The order comprises the families Aplosporellaceae, Botryosphaeriaceae, Melanopsaceae, Phyllostictaceae, Planistromellaceae and Saccharataceae. Furthermore, current study assessed two hypotheses; the first one being "All Botryosphaeriales species originated as endophytes and then switched into saprobes when their hosts died or into pathogens when their hosts were under stress"; the second hypothesis states that "There is a link between the conidial colour and nutritional mode in botryosphaerialean taxa". Ancestral state reconstruction and nutritional mode analyses revealed a pathogenic/saprobic nutritional mode as the ancestral character. However, we could not provide strong evidence for the first hypothesis mainly due to the significantly low number of studies reporting the endophytic botryosphaerialean taxa. Results also showed that hyaline and aseptate conidia were ancestral characters in Botryosphaeriales and supported the relationship between conidial pigmentation and the pathogenicity of Botryosphaeriales species.
Collapse
Affiliation(s)
- Achala R. Rathnayaka
- School of Science, Mae Fah Luang University, Chiang Rai 57100, Thailand
- Center of Excellence in Fungal Research, Mae Fah Luang University, Chiang Rai 57100, Thailand
- Department of Plant Medicine, National Chiayi University, 300 Syuefu Road, Chiayi City 60004, Taiwan
| | - K. W. Thilini Chethana
- School of Science, Mae Fah Luang University, Chiang Rai 57100, Thailand
- Center of Excellence in Fungal Research, Mae Fah Luang University, Chiang Rai 57100, Thailand
| | - Alan J. L. Phillips
- Faculdade de Ciências, Biosystems and Integrative Sciences Institute (BioISI), Universidade de Lisboa, Campo Grande, 1749-016 Lisbon, Portugal
| | - Jian-Kui Liu
- School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 610054, China
| | - Milan C. Samarakoon
- Department of Entomology and Plant Pathology, Faculty of Agriculture, Chiang Mai University, Chiang Mai 50200, Thailand
| | - E. B. Gareth Jones
- Department of Botany and Microbiology, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
| | - Samantha C. Karunarathna
- Center for Yunnan Plateau Biological Resources Protection and Utilization, College of Biological Resource and Food Engineering, Qujing Normal University, Qujing 655011, China
| | - Chang-Lin Zhao
- Key Laboratory for Forest Resources Conservation and Utilization in the Southwest Mountains of China, Ministry of Education, Southwest Forestry University, Kunming 650224, China
| |
Collapse
|
4
|
Masi M, Di Lecce R, Calice U, Linaldeddu BT, Maddau L, Superchi S, Evidente A. Diplofuranoxin, a disubstituted dihydrofuranone, was produced together with sphaeropsidin A and epi-sphaeropsidone by Diplodia subglobosa, an emerging ash (Fraxinus excelsior L.) pathogen in Europe. PHYTOCHEMISTRY 2022; 202:113302. [PMID: 35810877 DOI: 10.1016/j.phytochem.2022.113302] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 06/21/2022] [Accepted: 06/27/2022] [Indexed: 06/15/2023]
Abstract
An undescribed disubstituted dihydrofuranone, named diplofuranoxin, was isolated, together with the six well known metabolites sphaeropsidins A and C, epi-sphaeropsidone, mellein and cis- and trans-4-hydroxymelleins, from the fungal species Diplodia subglobosa, an emerging pathogen involved in the ash dieback aetiology in Europe. Currently, the disease represents the main threat to European ash heritage and the wood associated industry. Diplofuranoxin, was characterized essentially by NMR and HRESIMS spectra as (3Z)-3-(2,3-dihydroxybutylidene)-5-methyldihydrofuran-2(3H)-one. Its relative and absolute configuration was determined by joining NOESY NMR experiments and computational analysis of electronic circular dichroism spectrum. All the metabolites were screened for phytotoxic, antioomycetes and zootoxic activities and only sphaeropsidin A and epi-sphaeropsidone were active in two out of three bioassays performed. In addition, sphaeropsidin A completely inhibited mycelium growth of Phytophthora cambivora, whereas the inhibition rate of epi-sphaeropsidone was less than 50% at the higher concentration used. Both metabolites were inactive in the Artemia salina assay. Results obtained in this study have allowed to characterize for the first time the main metabolites produced in vitro by D. subglobosa and to increase the knowledge on the metabolic profile of Botryosphaeriaceae for a correct taxonomic classification of the strains belonging to this family.
Collapse
Affiliation(s)
- Marco Masi
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario Monte Sant'Angelo, Via Cintia 4, 80126, Napoli, Italy
| | - Roberta Di Lecce
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario Monte Sant'Angelo, Via Cintia 4, 80126, Napoli, Italy
| | - Umberto Calice
- Dipartimento di Scienze, Università della Basilicata, Viale dell'Ateneo Lucano 10, 85100, Potenza, Italy
| | - Benedetto Teodoro Linaldeddu
- Dipartimento Territorio e Sistemi Agro-Forestali, Università degli Studi di Padova, Viale dell'Università 16, Legnaro, 35020, Italy
| | - Lucia Maddau
- Dipartimento di Agraria, Sezione di Patologia Vegetale ed Entomologia, Università degli Studi di Sassari, Viale Italia 39, 07100, Sassari, Italy
| | - Stefano Superchi
- Dipartimento di Scienze, Università della Basilicata, Viale dell'Ateneo Lucano 10, 85100, Potenza, Italy
| | - Antonio Evidente
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario Monte Sant'Angelo, Via Cintia 4, 80126, Napoli, Italy.
| |
Collapse
|
5
|
Linaldeddu BT, Bregant C, Montecchio L, Brglez A, Piškur B, Ogris N. First Report of Diplodia fraxini and Diplodia subglobosa Causing Canker and Dieback of Fraxinus excelsior in Slovenia. PLANT DISEASE 2022; 106:26-29. [PMID: 34515500 DOI: 10.1094/pdis-06-21-1204-sc] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
In recent decades the vitality and productivity of European ash trees in Slovenia have been reduced by the onset of canker and dieback disease symptoms on young and old trees, identified primarily as ash dieback caused by Hymenoscyphus fraxineus. Given the limited information available about the etiology of this emerging disease, a study was carried out to isolate, identify, and characterize the fungal species involved in the observed ash symptoms. Field surveys were conducted in five forest sites where 50 symptomatic branch samples were collected. All samples were inspected and used for fungal isolation. Based on morphology, colony appearance, and DNA sequence data of the internal transcribed spacer region, 125 fungal colonies belonging to five species were isolated and identified. Only a few symptomatic ash samples yielded colonies of H. fraxineus, whereas Botryosphaeriaceae species were isolated with a high frequency, with Diplodia fraxini as the dominant species. A pathogenicity test proved that all isolated species were pathogenic on European ash, causing bark lesions and wood discoloration. All Botryosphaeriaceae species isolated in this study are reported for the first time on European ash in Slovenia.
Collapse
Affiliation(s)
- Benedetto T Linaldeddu
- Dipartimento Territorio e Sistemi Agro-Forestali, Università di Padova, 35020 Legnaro (PD), Italy
| | - Carlo Bregant
- Dipartimento Territorio e Sistemi Agro-Forestali, Università di Padova, 35020 Legnaro (PD), Italy
| | - Lucio Montecchio
- Dipartimento Territorio e Sistemi Agro-Forestali, Università di Padova, 35020 Legnaro (PD), Italy
| | - Ana Brglez
- Department of Forest Protection, Slovenian Forestry Institute, 1000 Ljubljana, Slovenia
| | - Barbara Piškur
- Department of Forest Protection, Slovenian Forestry Institute, 1000 Ljubljana, Slovenia
| | - Nikica Ogris
- Department of Forest Protection, Slovenian Forestry Institute, 1000 Ljubljana, Slovenia
| |
Collapse
|
6
|
Identification and Characterization of Nectria pseudotrichia Associated with Camellia Canker Disease in China. FORESTS 2021. [DOI: 10.3390/f13010029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Camellia japonica is a native tree species with high economic value that is widely cultivated in southern China. In recent years, canker disease has been observed in camellia plantations in Zhejiang Province, China, with the disease incidence rate in some plantations exceeding 20%. Canker disease severely affects the trunks and branches of C. japonica in China, but the causal agent has not yet been identified. In this study, the pathogen was isolated from infected C. japonica tissues through a conventional tissue isolation approach. Species identification was conducted using morphological methods combined with multilocus phylogenetic analysis. Pathogenicity was tested based on Koch’s postulates. The results showed that the pathogen could be isolated from the diseased bark of C. japonica ‘Hongluzhen’. The pathogen was identified as Nectria pseudotrichia based on morphological, cultural, and molecular traits. The inoculation of the pathogen into C. japonica ‘Hongluzhen’ caused necrotic lesions on healthy seedlings, and the fungus N. pseudotrichia could be re-isolated from such lesions. Therefore, N. pseudotrichia is the causal agent of canker disease affecting C. japonica in China.
Collapse
|
7
|
Fungi Detected in the Previous Year’s Leaf Petioles of Fraxinus excelsior and Their Antagonistic Potential against Hymenoscyphus fraxineus. FORESTS 2021. [DOI: 10.3390/f12101412] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
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.
Collapse
|
8
|
|