Search Results (4)

In the submerged fermentation process, the introduction of novel nutrient media as sources of carbon and nitrogen can enhance antifungal activity. In this study, we used a submerged fermentation process to find the optimal media for the Bacillus velezensis BP-1 strain to grow in, and that would boost its antifungal activity against Peyronellaea arachidicola. By using a single-factor test and central composite design (CCD) in the response surface methodology, the optimal fermentation medium for the B. velezensis BP-1 strain was identified. The antagonistic potential of B. velezensis BP-1 was assayed against the P. arachidicola fungus to manage web blotch disease in peanut plant leaves. The LB medium was screened as the best medium, with a maximum antifungal activity of 90% in comparison to the other mediums. Semolina flour as the carbon source, peanut root extract as the nitrogen source, and magnesium sulfate as the inorganic salt were selected as the best nutrient components in comparison to the others. The response surface methodology was optimized by using 15 g/L of semolina flour as the carbon source, 13.68 g/L of peanut root extract as the nitrogen source, and 0.50 g/L of magnesium sulfate as the inorganic salt, achieving 90% inhibition of P. arachidicola. The in vitro bioassays showed that the optimized fermentation broth of B. velezensis BP-1 had significant antifungal activity, with an inhibition rate of 88.34% against P. arachidicola. In the pot experiments on disease control, the management effects revealed that the pre-inoculation spray of the B. velezensis BP-1 broth had significant efficiency (96%) when compared to the post-inoculation spray of the B. velezensis BP-1 broth. These findings suggest that the optimized fermentation broth of the B. velezensis BP-1 strain had strong antifungal activity. This could be a potent biocontrol tool for aiding in the early disease management of web blotch in peanut plants. Full article

Ascochyta Blight (AB) is a major disease of many cool-season legumes globally. In field pea, three fungal pathogens have been identified to be responsible for this disease in Australia, namely Peyronellaea pinodes, Peyronellaea pinodella and Phoma koolunga. Limited genomic resources for these pathogens have been generated, which has hampered the implementation of effective management strategies and breeding for resistant cultivars. Using Oxford Nanopore long-read sequencing, we report the first high-quality, fully annotated, near-chromosome-level nuclear and mitochondrial genome assemblies for 18 isolates from the Australian AB complex. Comparative genome analysis was performed to elucidate the differences and similarities between species and isolates using phylogenetic relationships and functional diversity. Our data indicated that P. pinodella and P. koolunga are heterothallic, while P. pinodes is homothallic. More homology and orthologous gene clusters are shared between P. pinodes and P. pinodella compared to P. koolunga. The analysis of the repetitive DNA content showed differences in the transposable repeat composition in the genomes and their expression in the transcriptomes. Significant repeat expansion in P. koolunga’s genome was seen, with strong repeat-induced point mutation (RIP) activity being evident. Phylogenetic analysis revealed that genetic diversity can be exploited for species marker development. This study provided the much-needed genetic resources and characterization of the AB species to further drive research in key areas such as disease epidemiology and host–pathogen interactions. Full article

Citrus trees with cankers and dieback symptoms were observed in Bushehr (Bushehr province, Iran). Isolations were made from diseased cankers and branches. Recovered fungal isolates were identified using cultural and morphological characteristics, as well as comparisons of DNA sequence data of the nuclear ribosomal DNA-internal transcribed spacer region, translation elongation factor 1α, β-tubulin, and actin gene regions. Dothiorella viticola, Lasiodiplodia theobromae, Neoscytalidium hyalinum, Phaeoacremonium (P.) parasiticum, P. italicum, P. iranianum, P. rubrigenum, P. minimum, P. croatiense, P. fraxinopensylvanicum, Phaeoacremonium sp., Cadophora luteo-olivacea, Biscogniauxia (B.) mediterranea, Colletotrichum gloeosporioides, C. boninense, Peyronellaea (Pa.) pinodella, Stilbocrea (S.) walteri, and several isolates of Phoma, Pestalotiopsis, and Fusarium species were obtained from diseased trees. The pathogenicity tests were conducted by artificial inoculation of excised shoots of healthy acid lime trees (Citrus aurantifolia) under controlled conditions. Lasiodiplodia theobromae was the most virulent and caused the longest lesions within 40 days of inoculation. According to literature reviews, this is the first report of L. theobromae and N. hyalinum on citrus in Iran. Additionally, we report several Phaeoacremonium species, S. walteri, Pa. pinodella and C. luteo-olivacea on citrus trees for the first time in the world. Full article

A new polyketide containing the benzoisoquinoline-9-one moiety, peyronetide A (1), and three other new derivatives peyronetides B–D (2–4), as well as one known compound (5) were purified from the cultured broth of the endophytic fungus Peyronellaea sp. FT431, which was isolated from the Hawaiian indigenous plant, Verbena sp. The structures of the new compounds were determined through the analysis of HRMS and NMR spectroscopic data. Compounds 1, 2, and 5 showed cytotoxic activities against TK-10 (human kidney adenocarcinoma cells), cisplatin sensitive A2780S (human ovarian carcinoma cells), and cisplatin resistant A2780CisR cell lines, with IC₅₀ values between 6.7 to 29.2 μM. Full article