Symptomatic plant viroid infections in phytopathogenic fungi: A request for a critical reassessment

Viroids are pathogenic agents that have a small, circular noncoding RNA genome. They have been found only in plant species; therefore, their infectivity and pathogenicity in other organisms remain largely unexplored. In this study, we investigate whether plant viroids can replicate and induce symptoms in filamentous fungi. Seven plant viroids representing viroid groups that replicate in either the nucleus or chloroplast of plant cells were inoculated to three plant pathogenic fungi,Cryphonectria parasitica,Valsa mali, andFusarium graminearum. By transfection of fungal spheroplasts with viroid RNA transcripts, each of the three, hop stunt viroid (HSVd), iresine 1 viroid, and avocado sunblotch viroid, can stably replicate in at least one of those fungi. The viroids are horizontally transmitted through hyphal anastomosis and vertically through conidia. HSVd infection severely debilitates the growth ofV. malibut not that of the other two fungi, while inF. graminearumandC. parasitica, with deletion of dicer-like genes, the primary components of the RNA-silencing pathway, HSVd accumulation increases. We further demonstrate that HSVd can be bidirectionally transferred betweenF. graminearumand plants during infection. The viroids also efficiently infect fungi and induce disease symptoms when the viroid RNAs are exogenously applied to the fungal mycelia. These findings enhance our understanding of viroid replication, host range, and pathogenicity, and of their potential spread to other organisms in nature.

Download Full-text

Preliminary Screening of Isolated Mycoherbicidal Fungi for the Management of Noxious Weed Xanthiumstrumarium

Journal of AgriSearch ◽

10.21921/jas.v6i02.15758 ◽

2019 ◽

Vol 6 (02) ◽

Author(s):

AJAY KUMAR SINGH ◽

AKHILESH KUMAR PANDEY

Keyword(s):

Culture Filtrate ◽

Photosynthetic Pigment ◽

Phytopathogenic Fungi ◽

Herbicidal Activity ◽

Preliminary Screening ◽

Detached Leaf ◽

Noxious Weed ◽

Complete Collapse

Natural phytotoxins of fungi are great source for the discovery of new herbicide and its offer a benign and eco-friendly alternative to manage weed. Thus, this study aimed to select potential fungi with potent herbicidal activity for control ofweeds. In the present study, various phytopathogenic fungi were isolated from infected tissues of various weeds and evaluated againstXanthium strumarium, a problematic monocotyledonous weed of open lands, agriculture, horticulture and forests. Herbicidal potential of Cell Free Culture Filtrate (CFCF) of strains ofPhoma herbarum (FGCCW#18, FGCCW#43) Fusariummonilifromecoded as FGCCW#35 and Fusarium roseum coded as FGCCW#55againstXanthium strumariumwere evaluated by seedling and shoot cut bioassays. Maximum mortalities of shoots, seedlings and phytotoxic damage were obtainedfrom28 day sold cell free culture filtrate (CFCF) of FGCCW#18 at 100% concentration. Significant reduction in biological contents i.e. photosynthetic pigment and protein was observed in the host weed on treatment with the CFCF as determined by detached leaf bioassay. Phytotoxic damage such as severe wilting, chlorosis, necrosis and complete collapse of the entire parts of the weed were also noticed due to CFCF application.

Download Full-text

Categorization of Orthologous Gene Clusters in 92 Ascomycota Genomes Reveals Functions Important for Phytopathogenicity

Journal of Fungi ◽

10.3390/jof7050337 ◽

2021 ◽

Vol 7 (5) ◽

pp. 337

Author(s):

Daniel Peterson ◽

Tang Li ◽

Ana M. Calvo ◽

Yanbin Yin

Keyword(s):

Comparative Genomics ◽

Orthologous Gene ◽

Gene Clusters ◽

Phytopathogenic Fungi ◽

Secreted Proteins ◽

Economic Losses ◽

Comparative Genomic ◽

Signal Peptides ◽

Comparative Genomics Analysis

Phytopathogenic Ascomycota are responsible for substantial economic losses each year, destroying valuable crops. The present study aims to provide new insights into phytopathogenicity in Ascomycota from a comparative genomic perspective. This has been achieved by categorizing orthologous gene groups (orthogroups) from 68 phytopathogenic and 24 non-phytopathogenic Ascomycota genomes into three classes: Core, (pathogen or non-pathogen) group-specific, and genome-specific accessory orthogroups. We found that (i) ~20% orthogroups are group-specific and accessory in the 92 Ascomycota genomes, (ii) phytopathogenicity is not phylogenetically determined, (iii) group-specific orthogroups have more enriched functional terms than accessory orthogroups and this trend is particularly evident in phytopathogenic fungi, (iv) secreted proteins with signal peptides and horizontal gene transfers (HGTs) are the two functional terms that show the highest occurrence and significance in group-specific orthogroups, (v) a number of other functional terms are also identified to have higher significance and occurrence in group-specific orthogroups. Overall, our comparative genomics analysis determined positive enrichment existing between orthogroup classes and revealed a prediction of what genomic characteristics make an Ascomycete phytopathogenic. We conclude that genes shared by multiple phytopathogenic genomes are more important for phytopathogenicity than those that are unique in each genome.

Download Full-text

Pseudomonas eucalypticola sp. nov., a producer of antifungal agents isolated from Eucalyptus dunnii leaves

Scientific Reports ◽

10.1038/s41598-021-82682-7 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Yujing Liu ◽

Zhang Song ◽

Hualong Zeng ◽

Meng Lu ◽

Weiyao Zhu ◽

...

Keyword(s):

Dna Hybridization ◽

Antifungal Agents ◽

Novel Species ◽

Phytopathogenic Fungi ◽

Strictly Aerobic ◽

Rrna Sequence ◽

16S Rrna Sequence ◽

Eucalyptus Dunnii ◽

16S Rrna Sequence Analysis

AbstractPseudomonas are ubiquitously occurring microorganisms and are known for their ability to produce antimicrobials. An endophytic bacterial strain NP-1 T, isolated from Eucalyptus dunnii leaves, exhibits antifungal properties against five tested phytopathogenic fungi. The strain is a Gram-negative rod-shaped bacterium containing a single polar flagellum. It is strictly aerobic, grows at 4–37 °C, 2–5% NaCl, and pH 3–7. The 16S rRNA sequence analysis showed that NP-1 T belongs to the Pseudomonas genus. Phylogenetic analysis based on four concatenated partial genes (16S rDNA, gyrB, rpoB and rpoD) and the phylogenomic tree indicated that NP-1 T belongs to Pseudomonas fluorescens lineage but is distinct from any known Pseudomonas species. The G + C mol % of NP-1 T genome is 63.96, and the differences between NP-1 T and related species are larger than 1. The digital DNA-DNA hybridization and tetranucleotide signatures are 23.8 and 0.97, which clearly separates strain NP-1 T from its closest neighbours, Pseudomonas coleopterorum and Pseudomonas rhizosphaerae. Its phenotypic and chemotaxonomic features confirmed its differentiation from related taxa. The results from this polyphasic approach support the classification of NP-1 T as a novel species of Pseudomonas, and the name of Pseudomonas eucalypticola is thus proposed for this strain, whose type is NP-1 T (= CCTCC M2018494T = JCM 33572 T).

Download Full-text

Potential antifungal effects of silver nanoparticles (AgNPs) of different sizes against phytopathogenic Fusarium oxysporum f. sp. radicis-lycopersici (FORL) strains

SN Applied Sciences ◽

10.1007/s42452-021-04524-5 ◽

2021 ◽

Vol 3 (4) ◽

Author(s):

Ilgin Akpinar ◽

Muammer Unal ◽

Taner Sar

Keyword(s):

Silver Nanoparticles ◽

Fusarium Oxysporum ◽

Antifungal Agents ◽

New Technology ◽

Economic Loss ◽

Phytopathogenic Fungi ◽

Growth Media ◽

Mycelium Growth ◽

Antifungal Effects ◽

Critical Problems

AbstractFusarium species are the primary fungal pathogen affecting agricultural foodstuffs both in crop yield and economic loss. Due to these problems, control of phytopathogenic fungi has become one of the critical problems around the World. Nanotechnology is a new technology with potential in many fields, including agriculture. This study focused on determining potential effects of silver nanoparticles (AgNPs) with different nanosizes (3, 5, 8 and 10 nm) and at different concentrations (12.5–100 ppm) against phytopathogenic Fusarium oxysporum f. sp. radicis-lycopersici (FORL) strains. The maximum antifungal activity was achieved by decreasing nanosize and increasing concentration of AgNPs. Mycelium growth abilities were decreased about 50%, 75% and 90% by AgNPs treatment with 3 nm sizes at 25 ppm, 37.5 ppm and 50 ppm concentrations, respectively. The productivity of fungal biomass in the liquid growth media was found to be too limited at the 25–37.5 ppm of AgNPs concentrations with all sizes. In addition, both septation number and dimensions of micro- and macroconidia were found to be gradually decreased with the application of silver nanoparticles. This work showed that the low concentration of AgNPs could be used as potential antifungal agents and applied for control of phytopathogens.

Download Full-text

Antagonistic Activity of Lactic Acid Bacteria Against Phytopathogenic Fungi Isolated from Cherry Tomato (Solanum lycopersicum var. cerasiforme)

Current Microbiology ◽

10.1007/s00284-021-02416-w ◽

2021 ◽

Author(s):

Juan J. Manjarres Melo ◽

Alejandro Álvarez ◽

Cristina Ramirez ◽

German Bolivar

Keyword(s):

Lactic Acid ◽

Lactic Acid Bacteria ◽

Solanum Lycopersicum ◽

Phytopathogenic Fungi ◽

Antagonistic Activity ◽

Cherry Tomato

Download Full-text

Botanical Control of Citrus Green Mold and Peach Brown Rot on Fruits Assays Using a Persicaria acuminata Phytochemically Characterized Extract

Plants ◽

10.3390/plants10030425 ◽

2021 ◽

Vol 10 (3) ◽

pp. 425

Author(s):

Melina G. Di Liberto ◽

Gisela M. Seimandi ◽

Laura N. Fernández ◽

Verónica E. Ruiz ◽

Laura A. Svetaz ◽

...

Keyword(s):

Ecological Model ◽

Fungal Infections ◽

Ex Vivo ◽

Central Area ◽

Brown Rot ◽

Phytopathogenic Fungi ◽

Perennial Herb ◽

Huh7 Cells ◽

Gas Chromatography Mass Spectroscopy

Persicaria acuminata (Polygonaceae) is a perennial herb that grows in the central area of Argentina and it is commonly used by native populations to heal infected wounds and other conditions related to fungal infections. In this article, we explored the in vitro antifungal activity of its ethyl acetate extract against a panel of three fruit phytopathogenic fungi including: Penicillium digitatum, P. italicum, and Monilinia fructicola. The sesquiterpenes isolated from the extract were also evaluated against these strains, demonstrating that the dialdehyde polygodial was the responsible for this activity. In order to encourage the use of the extract rather than the pure compound, we displayed ex vivo assays using fresh oranges and peaches inoculated with P. digitatum and M. fructicola, respectively, and subsequently treated by immersion with an extract solution of 250 and 62.5 µg/mL, respectively. There were no statistically significant differences between the treatments with commercial fungicides and the extract over the control of both fruit rots. The concentration of the active compound present in the extract used on fruit experiments was determined by Gas Chromatography-Mass Spectroscopy. Finally, cytotoxicity evaluation against Huh7 cells showed that P. acuminata extract was less cytotoxic than the commercial fungicides at the assayed concentrations. After these findings we could conclude that a chemically characterized extract of P. acuminata should be further developed to treat fungal diseases in fruits from an agro-ecological model.

Download Full-text

Minerals, Essential Oils, and Biological Properties of Melissa officinalis L.

Plants ◽

10.3390/plants10061066 ◽

2021 ◽

Vol 10 (6) ◽

pp. 1066

Author(s):

Fahima Abdellatif ◽

Muhammad Akram ◽

Samir Begaa ◽

Mohammed Messaoudi ◽

Adel Benarfa ◽

...

Keyword(s):

Gas Chromatography ◽

Essential Oil ◽

Pathogenic Bacteria ◽

Antimicrobial Activities ◽

Biological Properties ◽

Phytopathogenic Fungi ◽

Melissa Officinalis ◽

Flame Ionization ◽

Analysis Technique ◽

Total Oil

This study describes the minerals elements, chemical composition, antioxidant and antimicrobial activities of Algerian Melissa officinalis plant. The essential oil (EO) was extracted by hydrodistillation (HD) using a Clevenger-type apparatus of dry leaves of M. officinalis and was analyzed by two techniques, gas chromatography coupled with flame ionization (GC-FID) and gas chromatography coupled with mass spectrometry (GC-MS). Eighteen minerals comprising both macro- and microelements (As, Br, K, La, Na, Sb, Sm, Ba, Ca, Ce, Co, Cr, Cs, Fe, Rb, Sc, Th, and Zn) were determined using neutron activation analysis technique for the first time from Algerian Melissa officinalis plant. Seventy-eight compounds were identified in the essential oil, representing 94.090% of the total oil and the yields were 0.470%. The major component was geranial (45.060%). Other predominant components were neral (31.720%) and citronellal (6.420%). The essential oil presented high antimicrobial activity against microorganisms, mainly five human pathogenic bacteria, one yeast, Candida albicans, and two phytopathogenic fungi. The results can be used as a source of information for the pharmaceutical industry and medical research.

Download Full-text