Phylogenetic diversity, trichothecene potential, and pathogenicity within Fusarium sambucinum species complex

The Fusarium sambucinum species complex (FSAMSC) is one of the most taxonomically challenging groups of fusaria, comprising prominent mycotoxigenic plant pathogens and other species with various lifestyles. Among toxins produced by members of the FSAMSC, trichothecenes pose the most significant threat to public health. Herein a global collection of 171 strains, originating from diverse hosts or substrates, were selected to represent FSAMSC diversity. This strain collection was used to assess their species diversity, evaluate their potential to produce trichothecenes, and cause disease on wheat. Maximum likelihood and Bayesian analyses of a combined 3-gene dataset used to infer evolutionary relationships revealed that the 171 strains originally received as 48 species represent 74 genealogically exclusive phylogenetically distinct species distributed among six strongly supported clades: Brachygibbosum, Graminearum, Longipes, Novel, Sambucinum, and Sporotrichioides. Most of the strains produced trichothecenes in vitro but varied in type, indicating that the six clades correspond to type A, type B, or both types of trichothecene-producing lineages. Furthermore, five strains representing two putative novel species within the Sambucinum Clade produced two newly discovered type A trichothecenes, 15-keto NX-2 and 15-keto NX-3. Strains of the two putatively novel species together with members of the Graminearum Clade were aggressive toward wheat when tested for pathogenicity on heads of the susceptible cultivar Apogee. In planta, the Graminearum Clade strains produced nivalenol or deoxynivalenol and the aggressive Sambucinum Clade strains synthesized NX-3 and 15-keto NX-3. Other strains within the Brachygibbosum, Longipes, Novel, Sambucinum, and Sporotrichioides Clades were nonpathogenic or could infect the inoculated floret without spreading within the head. Moreover, most of these strains did not produce any toxin in the inoculated spikelets. These data highlight aggressiveness toward wheat appears to be influenced by the type of toxin produced and that it is not limited to members of the Graminearum Clade.

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PHIALOMYCES MACROSPORUS REDUCES CERCOSPORA COFFEICOLA SURVIVAL ON SYMPTOMATIC COFFEE LEAVES

Coffee Science ◽

10.25186/cs.v14i1.1448 ◽

2019 ◽

Vol 14 (1) ◽

pp. 1

Author(s):

Marie Caroline Ferreira Laborde ◽

Deila Magna dos Santos Botelho ◽

Gabriel Alfonso Alvarez Rodriguez ◽

Mário Lúcio Vilela de Resende ◽

Marisa Vieira de Queiroz ◽

...

Keyword(s):

Plant Pathogens ◽

Disease Rate ◽

In Planta ◽

Necrotrophic Pathogen ◽

Initial Inoculum ◽

Saprobe Fungi ◽

Cercospora Coffeicola ◽

Brown Eye Spot

Saprobe fungi and necrotrophic pathogens share the same niche within crop stubble and the search for fungi non-pathogenic to plants that are able to displace the plant pathogens from its overwintering substrate contributes to the disease management. Brown eye spot (Cercospora coffeicola) is among the most important coffee diseases, it is caused by a necrotrophic pathogen that has decaying leaves as its major source of inoculum. We have screened saprobe fungi for the ability to reduce C. coffeicola sporulation and viability and determined the possible mechanisms involved in the observed biocontrol. A selected saprobe fungus, Phialomyces macrosporus, reduced the pathogen’s viability by 40% both in vitro and in vivo. The fungus acts through antibiosis and competition for nutrients. It produced both volatile and non-volatile compounds that inhibited C. coffeicola growth, sporulation, and viability. It also produced the tissue maceration enzyme (polygalacturonase), which reduces the pathogen both in detached leaves or in planta. The reduction in the fungal viability either by the saprobe fungus or its polygalacturonase-fraction supernatant resulted in the reduction of the disease rate. Therefore, P. macrosporus is a potential microbial agent that can be used in an integrated management of brown eye spot through the reduction of the initial inoculum of the pathogen that survives and builds up in infected leaves.

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Evaluation of in-vitro methods to select effective streptomycetes against toxigenic fusaria

PeerJ ◽

10.7717/peerj.6905 ◽

2019 ◽

Vol 7 ◽

pp. e6905 ◽

Cited By ~ 5

Author(s):

Elena Maria Colombo ◽

Cristina Pizzatti ◽

Andrea Kunova ◽

Claudio Gardana ◽

Marco Saracchi ◽

...

Keyword(s):

Plant Pathogens ◽

Culture Media ◽

Screening Methods ◽

Dual Culture ◽

In Planta ◽

In Vitro Method ◽

In Vitro Methods ◽

Strain Diversity ◽

Fungal Plant Pathogens

Biocontrol microorganisms are emerging as an effective alternative to pesticides. Ideally, biocontrol agents (BCAs) for the control of fungal plant pathogens should be selected by an in vitro method that is high-throughput and is predictive of in planta efficacy, possibly considering environmental factors, and the natural diversity of the pathogen. The purpose of our study was (1) to assess the effects ofFusariumstrain diversity (N= 5) and culture media (N= 6) on the identification of biological control activity ofStreptomycesstrains (N= 20) againstFusariumpathogens of wheat in vitro and (2) to verify the ability of our in vitro screening methods to simulate the activity in planta. Our results indicate that culture media,Fusariumstrain diversity, and their interactions affect the results of an in vitro selection by dual culture assay. The results obtained on the wheat-based culture media resulted in the highest correlation score (r= 0.5) with the in planta root rot (RR) inhibition, suggesting that this in vitro method was the best predictor of in planta performance of streptomycetes against Fusarium RR of wheat assessed as extension of the necrosis on the root. Contrarily, none of the in vitro plate assays using the media tested could appropriately predict the activity of the streptomycetes against Fusarium foot rot symptoms estimated as the necrosis at the crown level. Considering overall data of correlation, the activity in planta cannot be effectively predicted by dual culture plate studies, therefore improved in vitro methods are needed to better mimic the activity of biocontrol strains in natural conditions. This work contributes to setting up laboratory standards for preliminary screening assays ofStreptomycesBCAs against fungal pathogens.

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Phylogenetic Diversity and Mycotoxin Potential of Emergent Phytopathogens within the Fusarium tricinctum Species Complex

Phytopathology ◽

10.1094/phyto-09-21-0394-r ◽

2022 ◽

Author(s):

Imane Laraba ◽

Mark Busman ◽

David M. Geiser ◽

Kerry O'Donnell

Keyword(s):

Species Complex ◽

Phylogenetic Diversity ◽

Agricultural Research ◽

Distinct Species ◽

Culture Collections ◽

Strain Collection ◽

Food And Feed ◽

Feed Safety ◽

Large Survey ◽

Fusarium Tricinctum

Recent studies on multiple continents indicate members of the Fusarium tricinctum species complex (FTSC) are emerging as prevalent pathogens of small-grain cereals, pulses, and other economically important crops. These understudied fusaria produce structurally diverse mycotoxins, among which enniatins (ENNs) and moniliformin (MON) are the most frequent and of greatest concern to food and feed safety. Herein a large survey of fusaria in the Fusarium Research Center and Agricultural Research Service culture collections was undertaken to assess species diversity and mycotoxin potential within the FTSC. A 151-strain collection originating from diverse hosts and substrates from different agroclimatic regions throughout the world was selected from 460 FTSC strains to represent the breadth of FTSC phylogenetic diversity. Evolutionary relationships inferred from a 5-locus dataset, using maximum likelihood and parsimony, resolved the 151 strains as 24 phylogenetically distinct species, including nine that are new to science. Of the five genes analyzed, nearly full-length phosphate permease sequences contained the most phylogenetically informative characters, establishing its suitability for species-level phylogenetics within the FTSC. Fifteen of the species produced ENNs, MON, the sphingosine analog 2-amino-14,16- dimethyloctadecan-3-ol (AOD), and the toxic pigment aurofusarin (AUR) on a cracked corn kernel substrate. Interestingly, the five earliest diverging species in the FTSC phylogeny (i.e., F. iranicum, F. flocciferum, F. torulosum, Fusarium spp. FTSC 8 and 24) failed to produce AOD and MON, but synthesized ENNs and/or AUR. Moreover, our reassessment of nine published phylogenetic studies on the FTSC identified 11 additional novel taxa, suggesting this complex comprises at least 36 species.

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Inhibition of Phytophthora parasitica and P. capsici by Silver Nanoparticles Synthesized Using Aqueous Extract of Artemisia absinthium

Phytopathology ◽

10.1094/phyto-01-15-0006-r ◽

2015 ◽

Vol 105 (9) ◽

pp. 1183-1190 ◽

Cited By ~ 25

Author(s):

Mohammad Ali ◽

Bosung Kim ◽

Kevin D. Belfield ◽

David Norman ◽

Mary Brennan ◽

...

Keyword(s):

Silver Nanoparticles ◽

Aqueous Extract ◽

Dose Response ◽

Mycelial Growth ◽

Plant Pathogens ◽

Synthesis Methods ◽

In Planta ◽

Artemisia Absinthium ◽

Plant Disease Management

Application of nanoparticles for controlling plant pathogens is a rapidly emerging area in plant disease management, and nanoparticles synthesis methods that are economical and ecofriendly are extensively investigated. In this project, we investigated the potential of silver nanoparticles (AgNPs) synthesized with aqueous extract of Artemisia absinthium against several Phytophthora spp., which cause many economically important crop diseases. In in vitro dose-response tests conducted in microtiter plates, 10 µg ml−1 of AgNPs inhibited mycelial growth of P. parasitica, P. infestans, P. palmivora, P. cinnamomi, P. tropicalis, P. capsici, and P. katsurae. Detailed in vitro dose-response analyses conducted with P. parasitica and P. capsici revealed that AgNPs synthesized with A. absinthium extract were highly potent (IC50: 2.1 to 8.3 µg ml−1) and efficacious (100%) in inhibiting mycelial growth, zoospore germination, germ tube elongation, and zoospore production. Interestingly, AgNP treatment accelerated encystment of zoospores. Consistent with in vitro results, in planta experiments conducted in a greenhouse revealed that AgNP treatments prevented Phytophthora infection and improved plant survival. Moreover, AgNP in in planta experiments did not produce any adverse effects on plant growth. These investigations provide a simple and economical method for controlling Phytophthora with AgNP without affecting normal plant physiology.

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Optimization of laboratory conditions for biosynthesis of type A trichothecenes

Zbornik Matice srpske za prirodne nauke ◽

10.2298/zmspn0713035b ◽

2007 ◽

pp. 35-44 ◽

Cited By ~ 3

Author(s):

Aleksandra Bocarov-Stancic ◽

Vesna Jacevic ◽

Radmila Resanovic ◽

Milorad Bijelic

Keyword(s):

Type A ◽

Climatic Conditions ◽

Medium Composition ◽

Fusarium Sporotrichioides ◽

Metabolic Characteristics ◽

Laboratory Conditions ◽

Type A Trichothecenes ◽

C And N ◽

Definition Of

Type A trichothecenes, T-2 toxin and diacetoxyscirpenol - DAS, belong to one of the most toxic groups of fusariotoxins. Although larger quantities of them can be found more often in cooler parts of Europe, regarding their metabolic characteristics and the types of illnesses they provoke, it is obvious that even smaller quantities of these toxins can cause serious health disturbances of humans and animals in climatic conditions of Serbia. Having in mind the importance of these substances, the aim of this study was to carry out the optimization of laboratory conditions under which screening of Fusarium spp. isolates from Serbia, regarding T-2 toxin and DAS production, should be done. Four cultures of Fusarium sporotrichioides originating from different regions throughout the world, were under present investigation: ITM-391 (Italy), KF-38/1 (Poland), M-1-1 (Japan) and R-2301 (Germany). According to the previous literature data, all of these isolates were T-2 toxin producers, and some of them were also DAS producers. The influence of medium composition (different C and N atoms sources microelements etc), as well as aeration (in liquid media), on biosynthesis process of these mycotoxins, in vitro conditions was investigated. In the case of most Fusarium sporotrichioides isolates, highest yields of T-2 toxin and DAS were achieved under the conditions of more intense aeration, and with the use of glucose (5 or 20%) as a C atom source. Fermentation in semi-synthetic liquid medium, using a rotary shaker, was more suitable for screening the toxicity of the fungal isolates in pure culture because of shorter period of incubation, more simpler sample preparation, obtaining less interfering materials in crude toxin extracts, and possibility for more precise definition of factors influencing the yield of trichothecenes.

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Control Of Plant Diseases By An Allium-based Antimicrobial Formulation

10.20944/preprints202201.0091.v1 ◽

2022 ◽

Author(s):

Oladejo Oluwashina ◽

Jafargholi Imani

Keyword(s):

Fungal Pathogens ◽

Plant Pathogens ◽

Fruits And Vegetables ◽

Antimicrobial Properties ◽

Field Application ◽

Plant Diseases ◽

In Planta ◽

Xanthomonas Fragariae ◽

Alternaria Dauci

The objective of this work was to determine the antimicrobial properties of an allium-based antimicrobial formulation named VEG’LYS (https://phytoauxilium.com/) on the growth of plant pathogenic microorganisms such as fungi, oomycetes, and bacteria. Two anthracnose-related species of the fungal genus Colletotrichum, C. gloeosporioides, and C. fragariae, the oomycete Phytophthora cactorum and the bacterium Xanthomonas fragariae associated with strawberry plants and two fungi Alternaria dauci and Botrytis cinerea, associated with carrot plants were tested in vitro. In in planta experiments, A. dauci and B. cinerea were used.. VEG’LYS inhibited the growth of all plant pathogens tested. We found that both curative and preventive in planta treatments with VEG’LYS inhibited the growth of A. dauci and B. cinerea in carrot. Furthermore, after spraying VEG’LYS on carrot plants the expression of the Pathogenesis-related (PR) 10 gene correlated with the magnitude of infection both in treated and untreated plants. Additionally, it has been shown, that the field application of VEG’LYS on strawberry plants results in a reduction of bacterial and fungal pathogens of strawberry fruits stored in refrigerator. In summary, VEG’LYS is a potential resistance inducer that seems to be suitable for use in both curative and preventive treatments to reduce the diseases and rotting of fruits and vegetables caused by different plant pathogens.

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Genomic differences between the new Fusarium oxysporum f. sp. apii (Foa) race 4 on celery, the less virulent Foa races 2 and 3, and the avirulent on celery f. sp. coriandrii

BMC Genomics ◽

10.1186/s12864-020-07141-5 ◽

2020 ◽

Vol 21 (1) ◽

Author(s):

Peter Henry ◽

Sukhwinder Kaur ◽

Quyen Anh Tran Pham ◽

Radwan Barakat ◽

Samuel Brinker ◽

...

Keyword(s):

Species Complex ◽

Pcr Primers ◽

Single Copy ◽

Preliminary Evidence ◽

In Planta ◽

Conserved Genes ◽

Compatibility Group ◽

Race 2 ◽

Race 4

Abstract Background Members of the F. oxysporium species complex (FOSC) in the f. sp. apii (Foa) are pathogenic on celery and those in f. sp. coriandrii (Foci) are pathogenic on coriander (=cilantro). Foci was first reported in California in 2005; a new and highly aggressive race 4 of Foa was observed in 2013 in California. Preliminary evidence indicated that Foa can also cause disease on coriander, albeit are less virulent than Foci. Comparative genomics was used to investigate the evolutionary relationships between Foa race 4, Foa race 3, and the Foci, which are all in FOSC Clade 2, and Foa race 2, which is in FOSC Clade 3. Results A phylogenetic analysis of 2718 single-copy conserved genes and mitochondrial DNA sequence indicated that Foa races 3 and 4 and the Foci are monophyletic within FOSC Clade 2; these strains also are in a single somatic compatibility group. However, in the accessory genomes, the Foci versus Foa races 3 and 4 differ in multiple contigs. Based on significantly increased expression of Foa race 4 genes in planta vs. in vitro, we identified 23 putative effectors and 13 possible pathogenicity factors. PCR primers for diagnosis of either Foa race 2 or 4 and the Foci were identified. Finally, mixtures of conidia that were pre-stained with different fluorochromes indicated that Foa race 4 formed conidial anastomosis tubes (CATs) with Foci. Foa race 4 and Foa race 2, which are in different somatic compatibility groups, did not form CATs with each other. Conclusions There was no evidence that Foa race 2 was involved in the recent evolution of Foa race 4; Foa race 2 and 4 are CAT-incompatible. Although Foa races 3 and 4 and the Foci are closely related, there is no evidence that either Foci contributed to the evolution of Foa race 4, or that Foa race 4 was the recent recipient of a multi-gene chromosomal segment from another strain. However, horizontal chromosome transfer could account for the major difference in the accessory genomes of Foa race 4 and the Foci and for their differences in host range.

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A collection of bacterial isolates from the pig intestine reveals functional and taxonomic diversity

Nature Communications ◽

10.1038/s41467-020-19929-w ◽

2020 ◽

Vol 11 (1) ◽

Author(s):

David Wylensek ◽

Thomas C. A. Hitch ◽

Thomas Riedel ◽

Afrizal Afrizal ◽

Neeraj Kumar ◽

...

Keyword(s):

Gut Microbiota ◽

Bile Acids ◽

Sequence Data ◽

Novel Species ◽

Meta Analysis ◽

Gene Clusters ◽

In Vitro Assays ◽

The Novel ◽

Strain Collection

AbstractOur knowledge about the gut microbiota of pigs is still scarce, despite the importance of these animals for biomedical research and agriculture. Here, we present a collection of cultured bacteria from the pig gut, including 110 species across 40 families and nine phyla. We provide taxonomic descriptions for 22 novel species and 16 genera. Meta-analysis of 16S rRNA amplicon sequence data and metagenome-assembled genomes reveal prevalent and pig-specific species within Lactobacillus, Streptococcus, Clostridium, Desulfovibrio, Enterococcus, Fusobacterium, and several new genera described in this study. Potentially interesting functions discovered in these organisms include a fucosyltransferase encoded in the genome of the novel species Clostridium porci, and prevalent gene clusters for biosynthesis of sactipeptide-like peptides. Many strains deconjugate primary bile acids in in vitro assays, and a Clostridium scindens strain produces secondary bile acids via dehydroxylation. In addition, cells of the novel species Bullifex porci are coccoidal or spherical under the culture conditions tested, in contrast with the usual helical shape of other members of the family Spirochaetaceae. The strain collection, called ‘Pig intestinal bacterial collection’ (PiBAC), is publicly available at www.dsmz.de/pibac and opens new avenues for functional studies of the pig gut microbiota.

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Inhibition of Fungal and Bacterial Plant Pathogens In Vitro and In Planta with Ultrashort Cationic Lipopeptides

Applied and Environmental Microbiology ◽

10.1128/aem.01334-07 ◽

2007 ◽

Vol 73 (20) ◽

pp. 6629-6636 ◽

Cited By ~ 68

Author(s):

Arik Makovitzki ◽

Ada Viterbo ◽

Yariv Brotman ◽

Ilan Chet ◽

Yechiel Shai

Keyword(s):

Pseudomonas Syringae ◽

Pathogenic Bacteria ◽

Plant Pathogens ◽

Antimicrobial Agents ◽

Plant Protection ◽

Microscopic Analysis ◽

Plant Diseases ◽

In Planta ◽

Global Food Security

ABSTRACT Plant diseases constitute an emerging threat to global food security. Many of the currently available antimicrobial agents for agriculture are highly toxic and nonbiodegradable and cause extended environmental pollution. Moreover, an increasing number of phytopathogens develop resistance to them. Recently, we have reported on a new family of ultrashort antimicrobial lipopeptides which are composed of only four amino acids linked to fatty acids (A. Makovitzki, D. Avrahami, and Y. Shai, Proc. Natl. Acad. Sci. USA 103:15997-16002, 2006). Here, we investigated the activities in vitro and in planta and the modes of action of these short lipopeptides against plant-pathogenic bacteria and fungi. They act rapidly, at low micromolar concentrations, on the membranes of the microorganisms via a lytic mechanism. In vitro microscopic analysis revealed wide-scale damage to the microorganism's membrane, in addition to inhibition of pathogen growth. In planta potent antifungal activity was demonstrated on cucumber fruits and leaves infected with the pathogen Botrytis cinerea as well as on corn leaves infected with Cochliobolus heterostrophus. Similarly, treatment with the lipopeptides of Arabidopsis leaves infected with the bacterial leaf pathogen Pseudomonas syringae efficiently and rapidly reduced the number of bacteria. Importantly, in contrast to what occurred with many native lipopeptides, no toxicity was observed on the plant tissues. These data suggest that the ultrashort lipopeptides could serve as native-like antimicrobial agents economically feasible for use in plant protection.

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The impact of type VI secretion system, bacteriocins and antibiotics on competition amongst Soft-RotEnterobacteriaceae: Regulation of carbapenem biosynthesis by iron and the transcriptional regulator Fur

10.1101/497016 ◽

2018 ◽

Cited By ~ 2

Author(s):

Divine Yutefar Shyntum ◽

Ntombikayise Nkomo ◽

Alessandro Rino Gricia ◽

Ntwanano Luann Shigange ◽

Daniel Bellieny-Rabelo ◽

...

Keyword(s):

Growth Inhibition ◽

Plant Pathogens ◽

Soft Rot ◽

Secretion System ◽

Economic Losses ◽

Computational Techniques ◽

In Planta ◽

Type Vi Secretion System ◽

Type Vi Secretion

AbstractPlant microbial communities’ complexity provide a rich model for investigation on biochemical and regulatory strategies involved in interbacterial competition. Within these niches, the soft rotEnterobacteriaceae(SRE) comprise an emerging group of plant-pathogens inflicting soft rot/black-leg diseases and causing economic losses worldwide in a variety of crops. In this report, a range of molecular and computational techniques are utilized to survey the contribution of antimicrobial factors such as bacteriocins, carbapenem antibiotic and type VI secretion system (T6SS) in interbacterial competition among plant-pathogens/endophytes using an aggressive SRE as a case study (Pectobacterium carotovorumsubsp.brasiliensestrain PBR1692 –Pcb1692). A preliminary screening using next-generation sequencing of 16S rRNA comparatively analysing healthy and diseased potato tubers, followed byin vitrocompetition assays, corroborated the aggressiveness ofPcb1692 against several relevant taxa sharing this niche ranging from Proteobacteria toFirmicutes. The results showed growth inhibition of several Proteobacteria by Pcb1692 depends either on carbapenem or pyocin production. Whereas for targetedFirmicutes, only pyocin seems to play a role in growth inhibition byPcb1692. Further analyses elucidated that although T6SS confers no relevant advantage duringin vitrocompetition, a significant attenuation in competition by the mutant strain lacking a functional T6SS was observedin planta. Furthermore, production of carbapenem byPcb1692 was observably dependent on the presence of environmental iron and oxygen. Additionally, upon deletion offur, slyA andexpI regulators, carbapenem production ceased, implying a complex regulatory mechanism involving these three genes. Potential Fur binding sites found upstream ofslyA,carR andexpR inPectobacteriumgenomes harboring carbapenem-associated genes further suggests a conserved regulatory pattern in the genus, in which carbapenem might be modulated in response to iron through the control exerted by Fur over secondary regulators. Furthermore, we unveiled the striking role played by S-pyocin in growth inhibition within the SRE group.Authors SummaryFor many phytopathogenic bacteria, more is known about interactions within the host and virulence factors used for host colonisation while relatively less is known about microbe-microbe interactions and factors that shape niche colonisation. The soft rotEnterobacteriaceae(SRE) comprise an emerging group of phytopathogens causing soft rot/black-leg diseases in a variety of crops leading to huge economic losses worldwide. In this report, a range of molecular and computational techniques are utilized to survey the contribution of antimicrobial factors such as bacteriocins, carbapenem antibiotic and type VI secretion system (T6SS) in interbacterial competition among plant-pathogens/endophytes using an aggressive SRE as a case study (Pcb1692). Our results show thatPcb1692 inhibits growth of other SRE and several potato endophytes using either the type VI secretion, carbapenem or bacteriocins. Carbapenem plays a role in both inter and intrabacterial competitionin vitro, while thePcb1692T6SS plays a role in interbacterial competitionin planta(in potato tubers). We also demonstrate that carbapenem regulation requires the presence of environmental iron and oxygen in a complex network consisting ofPcb1692 Fur, SlyA, and ExpI. The presence of these gene homologs in several SREs suggests that they too can deploy similar antimicrobials to target other bacteria.

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