Alternaria alternata as endophyte and pathogen

DeMers, Mara

doi:10.1099/mic.0.001153

Cited by 58 publications

(38 citation statements)

References 159 publications

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“…Likewise, fungal communities were more sensitive and highly affected by the plant host, compartments, and fertilizer treatments. The majority of Fusarium and Alternaria species in the Ascomycota division are the most significant plant pathogens, these endophytes are capable of producing mycotoxins in cereal crops like rice and potentially affecting human health through the food chain (Fones et al, 2020;Demers, 2022). Interestingly, we found that the application of silicate and biofertilizer suppresses the relative abundance of such pathogens, Alternaria and Fusarium.…”

Section: Discussionmentioning

confidence: 77%

Divergent taxonomic responses of below-ground microbial communities to silicate fertilizer and biofertilizer amendments in two rice ecotypes

Mallano

Xi-nan²,

Wang³

et al. 2022

Front. Agron.

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Using silicate fertilizer and bacterial inoculum as biofertilizer is significant for increasing soil silicon (Si) availability and rice agronomic performance. To use microbial technology for sustainable agriculture, it is crucial to have a deeper knowledge of how microbial populations shift among the plant hosts and related compartments, as well as how they respond to various fertilization models. In this study, the effects of silicate fertilizer, a single bacterial strain Bacillus mucilagniosis as biofertilizer, and their integrated application on soil physiochemical properties and soil microbiota structure, composition, and diversity in two eco-geographically diverse races (Indica and Japonica rice) were evaluated. Plant compartment, cultivar type, and fertilizer treatments contributed to microbiome variation. Indica and Japonica harbor different root microbiota; notably, taxa enriched in the rhizosphere soil were more diverse than in the root. Bacterial genera Leptonema, Azospira, Aquabacterium, Fluviicola, Aquabacterium, Leptonema, and fungal genera Metarhizium, Malassezia, and Cladosporium all were found in the rice core microbiome. Both silicate and biofertilizer applications increase the relative abundance of Betaproteobacteria, Deltaproteobacteria, and Actinobacteria, while suppressing fungal pathogens Alternaria and Fusarium. Silicate and bacterial inoculum applications increased the soil pH, available silicon content (ASi), available phosphorous (AP), available potassium (AK), and organic carbon (OC), while reduced the total nitrogen (N). These changes were also associated with major bacterial phyla Spirochaetes, Bacteroidetes, Actinobacteria, and Proteobacteria, except for Acidobacteria, and fungal phyla Ascomycota, Mortierellomycota and unassigned fungi. Several treatment-specific biomarkers were revealed through Linear discriminant analysis effect size (LEfSe) analysis. In conclusion, the change in the structure of root-associated communities driven by plant compartment and genetics suggests dynamic interactions in the host plant microbiome. Short-term silicate and biofertilizer amendments improved soil physiochemical status and altered bacterial and saprotrophic fungal communities, which have important implications for sustainable rice production.

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Section: Discussionmentioning

confidence: 77%

Divergent taxonomic responses of below-ground microbial communities to silicate fertilizer and biofertilizer amendments in two rice ecotypes

Mallano

Xi-nan²,

Wang³

et al. 2022

Front. Agron.

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“…The species of Lecanicillium are known to be entomopathogens, mycoparasites, or endophytes [ 78 , 79 ]. Alternaria species are ubiquitous in the environment, with a number of species being major plant pathogens, saprophytes, endophytes, and opportunistic pathogens or allergens of humans [ 80 , 81 , 82 ]. As the leaf samples used in this study did not show any discernable symptoms of fungal disease, it is likely that the fungal strains isolated in this study are plant endophytic fungi.…”

Section: Discussionmentioning

confidence: 99%

Common but Nonpersistent Acquisitions of Plant Viruses by Plant-Associated Fungi

Cao

Liu

Pang

et al. 2022

Viruses

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Investigating a virus’s host range and cross-infection is important for better understanding the epidemiology and emergence of viruses. Previously, our research group discovered a natural infection of a plant RNA virus, cumber mosaic virus (genus Cucumovirus, family Bromoviridae), in a plant pathogenic basidiomycetous fungus, Rhizoctonia solani, isolated from a potato plant grown in the field. Here, we further extended the study to investigate whether similar cross-infection of plant viruses occurs widely in plant-associated fungi in natural conditions. Various vegetable plants such as spinach, leaf mustard, radish, celery, and other vegetables that showed typical virus-like diseases were collected from the fields in Shandong Province, China. High-throughput sequencing revealed that at least 11 known RNA viruses belonging to different genera, including Potyvirus, Fabavirus, Polerovirus, Waikavirus, and Cucumovirus, along with novel virus candidates belonging to other virus genera, infected or associated with the collected vegetable plants, and most of the leaf samples contained multiple plant viruses. A large number of filamentous fungal strains were isolated from the vegetable leaf samples and subjected to screening for the presence of plant viruses. RT-PCR and Sanger sequencing of the PCR products revealed that among the 169 fungal strains tested, around 50% were carrying plant viruses, and many of the strains harbored multiple plant viruses. The plant viruses detected in the fungal isolates were diverse (10 virus species) and not limited to particular virus genera. However, after prolonged maintenance of the fungal culture in the laboratory, many of the fungal strains have lost the virus. Sequencing of the fungal DNA indicated that most of the fungal strains harboring plant viruses were related to plant pathogenic and/or endophytic fungi belonging to the genera Alternaria, Lecanicillium, and Sarocladium. These observations suggest that the nonpersistent acquisition of plant viruses by fungi may commonly occur in nature. Our findings highlight a possible role for fungi in the life cycle, spread, and evolution of plant viruses.

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“…The ITS region is widely accepted in the mycology community as the DNA barcoding marker with the highest probability for the precise identification of a broad range of fungal species ( Schoch et al, 2012 ; Raja et al, 2017 ). A. alternata species are commonly isolated in plants existing as endophytes or pathogens and they display varied symbiotic lifestyles and wide host ranges ( Lou et al, 2013 ; De Mers, 2022 ). Fungal species such as A. alternata which are broadly delineated due to their unstable taxonomy and limited morphological characteristics for species delimination, are often further delineated using phylogenetic analysis.…”

Section: Discussionmentioning

confidence: 99%

“…In our phylogenetic analysis of the three fungal isolates it was revealed that these isolates closely cluster with Alternaria species. However, for A. alternata there are few clades, thus limiting the power of further species delineation using evolutionary relationship ( De Mers, 2022 ). Endophytic isolates of A. alternata have been shown to exist as asymptomatic symbionts with no apparent ability to cause plant disease ( Spurr and Welty, 1975 ).…”

Section: Discussionmentioning

confidence: 99%

Secondary metabolites produced by endophytic fungi, Alternaria alternata, as potential inhibitors of the human immunodeficiency virus

et al. 2022

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Antiretroviral treatment has significantly reduced human immunodeficiency virus infection and mortality. However, the current treatment regimen is limited by adverse side effects, the emergence of drug resistance, and the inability to eliminate viral reservoirs. Here, fifteen endophytic fungi were isolated from Sclerocarya birrea and Hypoxis plants. Crude extracts of Alternaria alternata (strain ID PO4PR1, PO4PR2, and PO2PL1) of the fifteen isolate’s crude extracts showed anti-HIV-1 activity in TZM-bl cell line at inhibitory concentration (IC50) values ranging from 0.017 to 1.170 μg/ml. The three crude extracts also maintained the virus replication inhibition profile on PBMCs and CD4+ T cells at concentrations ranging from 0.3 to 50.2 ng/ml. Partial purification using the solid phase extraction and analysis with Gas Chromatography-Mass spectrophotometry showed a diverse profile. The bioactive compounds were identified based on peak area, retention time, similarity index. The major compounds from GC-MS analysis of A. Alternata revealed the existence of cyclotrisiloxane octamethyl (22.92%); Propaninitrile (16,67%); Pyrrolol[1,2-a]pyrazine-1,4-dione, hexahydro-3-(2-methyl propyl) (10.42%); Silane, diethylethoxy(2-ethoxyethyloxy) (4.17%); Coumarin, 3,4-dihydro-4,5,7-trimethyl- 4,5,7-Trimethyl-2-chromanone (13.7%) and 1,2-Cyclobutanedicarbonitrile (2.08%) with previously reported biological activities such as antimicrobial, anti-inflammatory and antioxidant properties. Therefore, these bioactive compounds from A. alternata fungal endophytes could be repurposed as potential anti-HIV agents. This study showed the potential of endophytic fungi, Alternaria alternata from S. birrea, and Hypoxis species as producers of anti-HIV compounds.

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Alternaria alternata as endophyte and pathogen

Cited by 58 publications

References 159 publications

Divergent taxonomic responses of below-ground microbial communities to silicate fertilizer and biofertilizer amendments in two rice ecotypes

Divergent taxonomic responses of below-ground microbial communities to silicate fertilizer and biofertilizer amendments in two rice ecotypes

Common but Nonpersistent Acquisitions of Plant Viruses by Plant-Associated Fungi

Secondary metabolites produced by endophytic fungi, Alternaria alternata, as potential inhibitors of the human immunodeficiency virus

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