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With the development of industry and modern manufacturing, nondegradable low-density polyethylene (LDPE) has been widely used, posing a rising environmental hazard to natural ecosystems and public health. In this study, we isolated a series of LDPE-degrading fungi from landfill sites and carried out LDPE degradation experiments by combining highly efficient degrading fungi in pairs. The results showed that the mixed microorganisms composed of Alternaria sp. CPEF-1 and Trametes sp. PE2F-4 (H-3 group) had a greater degradation effect on heat-treated LDPE (T-LDPE). After 30 days of inoculation with combination strain H-3, the weight loss rate of the T-LDPE film was approximately 154% higher than that of the untreated LDPE (U-LDPE) film, and the weight loss rate reached 0.66 ± 0.06%. Environmental scanning electron microscopy (ESEM) and Fourier transform infrared spectroscopy (FTIR) were used to further investigate the biodegradation impacts of T-LDPE, including the changes on the surface and depolymerization of the LDPE films during the fungal degradation process. Our findings revealed that the combined fungal treatment is more effective at degrading T-LDPE than the single strain treatment, and it is expected that properly altering the composition of the microbial community can help lessen the detrimental impact of plastics on the environment.

BBX genes play an important role in plant growth, development, and stress response. However, systematic analysis of BBX gene family regarding resistance to fungal infections has not been previously conducted in Chrysanthemum. In this study, a systematic analysis of the BBX gene family was performed, and its function in defense of necrotrophic fungus Alternaria sp. has been probed into through publicly available genome and RNA-seq data of Chrysanthemum after Alternaria sp. infection. The systematic analyses included identifying the BBX gene family in Chrysanthemum, their evolutionary relationships, conserved domains, motifs, gene structure, cis -acting elements, and collinearity. Based on the RNA-seq data analyses and expressional pattern, CmBBX32 was selected as a candidate gene for further investigation because it responded continuously to the infection and up-regulated expression when Chrysanthemum was inoculated with Alternaria sp. Gene expression analysis showed the expression of CmBBX32 increased sharply during the infection process, and was highest in flowers. Besides, virus-induced gene silencing (VIGS) of CmBBX32 in Chrysanthemum reduced the resistance to Alternaria sp. infection, as evidenced by phenotypic analysis of infection symptoms, microscopic examination of spore germination and hyphal growth, as well as quantitative analysis of the marker gene associated with the SA and JA defense pathways. Overall, the data generated in this study should form the basis for future functional characterizations of BBX genes in Chrysanthemum, especially regarding the resistance to biological stress in Chrysanthemum.

Background Alternaria sp. MG1, an endophytic fungus isolated from grape, is a native producer of resveratrol, which has important application potential. However, the metabolic characteristics and physiological behavior of MG1 still remains mostly unraveled. In addition, the resveratrol production of the strain is low. Thus, the whole-genome sequencing is highly required for elucidating the resveratrol biosynthesis pathway. Furthermore, the metabolic network model of MG1 was constructed to provide a computational guided approach for improving the yield of resveratrol. Results Firstly, a draft genomic sequence of MG1 was generated with a size of 34.7 Mbp and a GC content of 50.96%. Genome annotation indicated that MG1 possessed complete biosynthesis pathways for stilbenoids, flavonoids, and lignins. Eight secondary metabolites involved in these pathways were detected by GC–MS analysis, confirming the metabolic diversity of MG1. Furthermore, the first genome-scale metabolic network of Alternaria sp. MG1 (named i YL1539) was reconstructed, accounting for 1539 genes, 2231 metabolites, and 2255 reactions. The model was validated qualitatively and quantitatively by comparing the in silico simulation with experimental data, and the results showed a high consistency. In i YL1539, 56 genes were identified as growth essential in rich medium. According to constraint-based analysis, the importance of cofactors for the resveratrol biosynthesis was successfully demonstrated. Ethanol addition was predicted in silico to be an effective method to improve resveratrol production by strengthening acetyl-CoA synthesis and pentose phosphate pathway, and was verified experimentally with a 26.31% increase of resveratrol. Finally, 6 genes were identified as potential targets for resveratrol over-production by the recently developed methodology. The target-genes were validated using salicylic acid as elicitor, leading to an increase of resveratrol yield by 33.32% and the expression of gene 4CL and CHS by 1.8- and 1.6-fold, respectively. Conclusions This study details the diverse capability and key genes of Alternaria sp. MG1 to produce multiple secondary metabolites. The first model of the species Alternaria was constructed, providing an overall understanding of the physiological behavior and metabolic characteristics of MG1. The model is a highly useful tool for enhancing productivity by rational design of the metabolic pathway for resveratrol and other secondary metabolites.

Fungal diseases pose a major threat to ornamental plants, with an increasing percentage of pathogen-driven host losses. In ornamental plants, management of the majority of fungal diseases primarily depends upon chemical control methods that are often non-specific. Host basal resistance, which is deficient in many ornamental plants, plays a key role in combating diseases. Despite their economic importance, conventional and molecular breeding approaches in ornamental plants to facilitate disease resistance are lagging, and this is predominantly due to their complex genomes, limited availability of gene pools, and degree of heterozygosity. Although genetic engineering in ornamental plants offers feasible methods to overcome the intrinsic barriers of classical breeding, achievements have mainly been reported only in regard to the modification of floral attributes in ornamentals. The unavailability of transformation protocols and candidate gene resources for several ornamental crops presents an obstacle for tackling the functional studies on disease resistance. Recently, multiomics technologies, in combination with genome editing tools, have provided shortcuts to examine the molecular and genetic regulatory mechanisms underlying fungal disease resistance, ultimately leading to the subsequent advances in the development of novel cultivars with desired fungal disease-resistant traits, in ornamental crops. Although fungal diseases constitute the majority of ornamental plant diseases, a comprehensive overview of this highly important fungal disease resistance seems to be insufficient in the field of ornamental horticulture. Hence, in this review, we highlight the representative mechanisms of the fungal infection-related resistance to pathogens in plants, with a focus on ornamental crops. Recent progress in molecular breeding, genetic engineering strategies, and RNAi technologies, such as HIGS and SIGS for the enhancement of fungal disease resistance in various important ornamental crops, is also described.

Catharanthus roseus (Vinca) is a perennial herbaceous plant that is renowned for its abundance of vincristine (VCR) and vinblastine (VBL). These vinca alkaloids possess valuable anticancer properties and have been extensively used in chemotherapy treatment for various type of cancers. However, the current supply of these vinca alkaloids is reliant on plant material with low productivity and high costs. Endophytic fungi, a category of symbiotic mycota that are capable of synthesizing their host plant-specific bioactive compounds, have gained significant attention as a bioreactor for large-scale production of vinca alkaloids. In this study, a total of 34 endophytic fungal strains were isolated from stem and root tissues of C. roseus . The isolated endophytic fungi were taxonomically characterized as Alternaria sp., Talaromyces sp., and Cladosporium sp. by morphological observation and sequence analysis of the ITS region of rDNA. Three endophytic fungal strains were identified to be capable of synthesizing VCR and VBL by UPLC/MRM-MS analysis. The fungal strain Alternaria DC1 was determined to be the most prolific producer, producing VCR and VBL at concentrations of 177.6 and 114.8 µg/L, respectively. The Talaromyces DC2 strain followed with VCR and VBL yields of 44.0 and 111.6 µg/L, respectively. While the fungal strain Cladosporium DC3 was identified as a producer of VCR (36.9 µg/L) and VBL (99.6 µg/L) for the first time. These endophytic fungi exhibit the potential to serve as viable sources for the production of vinca alkaloids on a larger scale.

Two new compounds isobenzofuranone A (1) and indandione B (2), together with eleven known compounds (3–13) were isolated from liquid cultures of an endophytic fungus Alternaria sp., which was obtained from the medicinal plant Morinda officinalis. Among them, the indandione (2) showed a rarely occurring indanone skeleton in natural products. Their structures were elucidated mainly on the basis of extensive spectroscopic data analysis. All of the compounds were evaluated with cytotoxic and α-glucosidase inhibitory activity assays. Compounds 11 and 12 showed significant inhibitory activities against four tumor cell lines; MCF-7, HepG-2, NCI-H460 and SF-268, with IC50 values in the range of 1.91–9.67 μM, and compounds 4, 5, 9, 10, 12 and 13 showed excellent inhibitory activities against α-glucosidase with IC50 values in the range of 12.05–166.13 μM.

Racemic new cyclohexenone and cyclopentenone derivatives, (±)-(4R*,5S*,6S*)-3-amino-4,5,6-trihydroxy-2-methoxy-5-methyl-2-cyclohexen-1-one (1) and (±)-(4S*,5S*)-2,4,5-trihydroxy-3-methoxy-4-methoxycarbonyl-5-methyl-2-cyclopenten-1-one (2), and two new xanthone derivatives 4-chloro-1,5-dihydroxy-3-hydroxymethyl-6-methoxycarbonyl-xanthen-9-one (3) and 2,8-dimethoxy-1,6-dimethoxycarbonyl-xanthen-9-one (4), along with one known compound, fischexanthone (5), were isolated from the culture of the mangrove endophytic fungus Alternaria sp. R6. The structures of these compounds were elucidated by analysis of their MS (Mass), one and two dimensional NMR (nuclear magnetic resonance) spectroscopic data. Compounds 1 and 2 exhibited potent ABTS [2,2′-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid)] scavenging activities with EC50 values of 8.19 ± 0.15 and 16.09 ± 0.01 μM, respectively. In comparison to Triadimefon, compounds 2 and 3 exhibited inhibitory activities against Fusarium graminearum with minimal inhibitory concentration (MIC) values of 215.52 and 107.14 μM, respectively, and compound 3 exhibited antifungal activity against Calletotrichum musae with MIC value of 214.29 μM.

Three new resveratrol derivatives, namely, resveratrodehydes A–C (1–3), were isolated from the mangrove endophytic fungus Alternaria sp. R6. The structures of these compounds were elucidated by analysis of their MS, 1D and 2D NMR spectroscopic data. All compounds showed broad-spectrum inhibitory activities against three human cancer cell lines including human breast MDA-MB-435, human liver HepG2, and human colon HCT-116 by MTT assay (IC50 < 50 μM). Among them, compounds 1 and 2 both exhibited marked cytotoxic activities against MDA-MB-435 and HCT-116 cell lines (IC50 < 10 μM). Additionally, compounds 1 and 3 showed moderate antioxidant activity by DPPH radical scavenging assay.

Common bean root microbiome was used to research for potential biocontrol agents of phytopathogenic fungi as Fusarium sp., Macrophomina sp., and Alternaria sp. causal agents of root rot disease on host plants. Therefore, a bacterial collection of 90 endophytic and rhizospheric isolates was established from field-grown common bean plants in Tunisia and screened for their antifungal activity against pathogenic fungal strains. Antifungal activity was checked at biochemical and genetic levels. Twelve bacterial strains exhibited up to 71% of inhibition of the three pathogenic strains of Fusarium sp., Macrophomina sp., and Alternaria sp. Biocontrol assays conducted under controlled conditions demonstrated that Bacillus amyloliquefaciens , Bacillus halotolerans , Bacillus velezensis , Agrobacterium fabrum , and Pseudomonas lini displayed the highest protective effect on common bean cv. Coco blanc. These bacterial strains were associated with significant plant growth promotion up to 217%, in comparison with control plants. Biochemical analysis of the antagonistic and plant growth promoting activity revealed the production of xylanases, chitinases, siderophore, hydrogen cyanide, phosphate-solubilizing activity, and the production of indole-3-acetic acid, particularly in Bacillus spp. strains. Polymerase chain reaction revealed the presence of lipopeptide biosynthetic genes encoding surfactin, iturin, bacillomycin, and fengycin. The study unveiled that common bean root microbiome contains potential bacterial strains that exhibit efficient biocontrol activity of Fusarium sp., Macrophomina sp., and Alternaria sp., and act as plant growth promoters. Considering various plant growth promoting and biocontrol traits, the study showed the superiority of the Bacillus spp. strains among different common bean root microbiomes.

We compared the performance of Brussels sprout ( Brassica oleracea var. gemmifera ) cultivars in New Hampshire and evaluated the effects of topping (apical meristem removal) on marketable yields. A total of 23 cultivars were evaluated in the study, with 8 to 16 cultivars evaluated in any given year. We identified several cultivars that produced moderate to high yields of well-spaced, uniform sprouts that had few Alternaria blight ( Alternaria sp.) symptoms, and identified many others, including all red cultivars evaluated, that produced very low yields consistently. In 2013, 2014, and 2015, we used a replicated split-plot experimental design with cultivar as the main plot and topping treatment as the subplot, to evaluate the effects of topping plants. Early and midseason cultivars showed increased yields in response to topping, unless topping was performed too early. Cultivars with sprouts that did not reach marketable size within our growing season generally produced low yields, and topping had no effect on yields. To explore the effects of topping at different dates, we evaluated three cultivars on seven different topping dates plus an untopped control in 2015 and 2017. In addition to reducing stalk height by limiting late-season growth, topping affected marketable yields by affecting the number of sprouts that were either undersized or oversized. The ideal topping date window for minimizing defects and maximizing yields varied slightly for each cultivar, ranging from early to late September.