Pathogen Fusarium Oxysporum Research Articles

Identification of antagonistic fungi and their antifungal activities against aconite root rot pathogens

ABSTRACT Root rot is one of the main diseases affecting Aconitum carmichaelii Debx. during cultivation, seriously limiting yields of this herb. Currently, there is no effective control measure for aconite root rot. The antifungal activities of antagonistic strains against aconite root rot pathogens (Fusarium proliferatum, Fusarium solani, and Fusarium oxysporum) were investigated in this study. Three antagonistic strains, JKT7, JKT28 and JKT39, were screened and identified as Trichoderma asperellum, Trichoderma hamatum and Trichoderma virens, respectively. Dual culture tests showed that the inhibition rates of the three Trichoderma strains on the pathogens were all approximately 70%. The volatile metabolites had inhibitory effects on the mycelial growth of pathogens, while the nonvolatile metabolites in the culture filtrates did not show significant inhibitory effects. The volatile components analyzed by GC‒MS were mainly ketones, esters, and alcohols. These results indicate that these strains of Trichoderma and their secondary metabolites have antimicrobial activities against the pathogens of aconite root rot. This study could provide a scientific basis for the biocontrol of aconite root rot.

Plant growth promotion and antifungal activities of the mango phyllosphere bacterial consortium for the management of Fusarium wilt disease in pea (Pisum sativum L.)

Root rot caused by the pathogen Fusarium oxysporum is the number one cause of pea plant (P. sativum L.) death. There are many potential advantages to using rhizobacteria, endophytic bacteria and phyllospheric bacteria for managing plant diseases and promoting plant growth. This study investigated the potentiality of consortium species of bacteria to suppress root rot disease and their ability to promote the growth of pea plants compared with their individual and control plants. A total of 55 phyllospheric bacteria were isolated from mango flower and Bacillus sp. LBF- 02, Bacillus sp. LBF- 03 and Bacillus sp. LBF- 05 showed the most potent antimicrobial activity against root rot pathogens in a dual culture assay. Identification of phyllobacterial strain LBF- 01, LBF- 03 and LBF-05 were done by 16S rDNA sequence analysis using 704f forward primer (50-AGATTTTCCGACGGCAGGTT-30) and 907r reverse primer (50-CCGTCAATTCMTTTRAGTTT-30) with the PCR conditions. Their ability to solubilize phosphate, produce ammonia, siderophore and indole acetic acid, as well as produce extracellular enzymes in vitro was excellent. The results of a greenhouse study found that pea seed treated with consortium isolate significantly increased high germination rates and vigour indexes, as well as shoot and root length, fresh and dry weights, as compared with seed treated with single isolate and control. The defense enzyme activities in consortium treated pots were higher than those in individual and control pots. The plants treated with consortium exhibited higher levels of chlorophyll and carotenoids content in their leaves compared to the untreated control and single treated plants. A significant variation in the chemical profile of pea plants was found (F7,16 ? 2.598; P ? 0.048) resulting from different treatments (T1-T8). After evaluating a variety of growth and microbiological parameters, it was concluded that inoculation with the microbial consortium contributed to raising healthy and vigorously growing pea seedlings in greenhouse conditions, which is applicable in the field in future for sustainable farming.

Induced Expression of CYP51a and HK1 Genes Associated with Penconazole and Fludioxonil Resistance in the Potato Pathogen Fusarium oxysporum.

Preventing antifungal resistance development and identifying pathogens with high, medium, and low risk of resistance development to a particular fungicide or fungicide class is crucial in the fight against phytopathogens. We characterized the sensitivity of potato wilt-associated Fusarium oxysporum isolates to fludioxonil and penconazole and assessed the effect of these fungicides on the expression of fungal sterol-14-α-demethylase (CYP51a) and histidine kinase (HK1) genes. Penconazole stunted the growth of F. oxysporum strains at all concentrations used. While all isolates were susceptible to this fungicide, concentrations of up to 1.0 μg/mL were insufficient to cause a 50% inhibition. At low concentrations (0.63 and 1.25 μg/mL), fludioxonil stimulated growth in F. oxysporum. With an increase in the concentration of fludioxonil, only one strain (F. oxysporum S95) exhibited moderate sensitivity to the fungicide. Interaction of F. oxysporum with penconazole and fludioxonil leads to respective elevated expressions of the CYP51a and HK1 genes, which upsurge with increasing concentration of the fungicides. The data obtained indicate that fludioxonil may no longer be suitable for potato protection and its continuous use could only lead to an increased resistance with time.

Isolation and screening of Pseudomonas fluorescens isolates against Fusarium oxysporum f. sp. radicis-lycopersici and their effects on seedling growth of Paraserianthes falcataria

Abstract. Yusran Y. 2023. Isolation and screening of Pseudomonas fluorescens isolates against Fusarium oxysporum f.sp. radicis-lycopersici and their effects on seedling growth of Paraserianthes falcataria. Biodiversitas 24: 2294-2301. Pseudomonas fluorescens plays a major role in biological control of pathogens and plant growth promotion as well with various mechanisms. The aim of the present study was to determine the biochemical characteristics of several Pseudomonas spp. isolates and to screen them against root pathogenic fungus Fusarium oxysporum f.sp radicis-lycopersici (FORL) and to evaluate their effect on the growth enhancement of Paraserianthes falcataria (L.) I.C. Nielsen seedlings. About 28 Pseudomonas fluorescens isolates were isolated from the rhizosphere of several plants and identified based on their physiological and morphological characters as well as their biochemical reactions. All isolates were tested for their ability to suppress FORL growth in vitro. All isolates inhibited FORL growth with varying inhibition zones. Six P. fluorescens isolates showed highest inhibition zones, namely TMTP4, TMTP5, TMTP6, SCPA1, SCPB3 and Proradix. The results showed that eight Pseudomonas isolates, namely TMTP4, TMTP5, TMTP6, SCPA1, SCPB3, SMPB3, TMTA2 and Proradix had a significantly different effect compared to the control treatment in increasing the growth of Paraserianthes seedlings. Based on our findings, it was confirmed that some P. fluorescens isolates could be used as potential bio-inoculants for controlling plant diseases caused by FORL and as a biological fertilizer to increase plant growth.

An LRR receptor kinase controls ABC transporter substrate preferences during plant growth-defense decisions

The exporter of the auxin precursor indole-3-butyric acid (IBA), ABCG36/PDR8/PEN3, from the model plant Arabidopsis has recently been proposed to also function in the transport of the phytoalexin camalexin. Based on these bonafide substrates, it has been suggested that ABCG36 functions at the interface between growth and defense. Here, we provide evidence that ABCG36 catalyzes the direct, ATP-dependent export of camalexin across the plasma membrane. We identify the leucine-rich repeat receptor kinase, QIAN SHOU KINASE1 (QSK1), as a functional kinase that physically interacts with and phosphorylates ABCG36. Phosphorylation of ABCG36 by QSK1 unilaterally represses IBA export, allowing camalexin export by ABCG36 conferring pathogen resistance. As a consequence, phospho-dead mutants of ABCG36, as well as qsk1 and abcg36 alleles, are hypersensitive to infection with the root pathogen Fusarium oxysporum, caused by elevated fungal progression. Our findings indicate a direct regulatory circuit between a receptor kinase and an ABC transporter that functions to control transporter substrate preference during plant growth and defense balance decisions.

Evaluation of liposomal hydrocolloidal NPs loaded by tea tree oil as antifungal agent in vitro and in vivo investigations: Preclinical studies

Fungi have a great ability and a wide variety of mechanisms to endure the toxicity of current antifungal agents. Researchers are working to find new therapeutic agents to combat the resistance ability of fungi. Almost all commercial antifungal agents have a wide variety of side effects on human health. This study aims to introduce tea tree oil nanoparticles as antifungal delivery termed TNSAD, which contains hybrid tea tree oil attached chitosan in a liposomal formulation, and assess its antifungal activity using in vitro and in vivo infection models. Tea tree oil was first coated by chitosan, then inserted inside liposomal bilayers, and finally functionalized by a layer of chitosan, forming the TNSAD. The antifungal activity was evaluated against four different invasive, opportunistic, and zoonotic fungal pathogens (Aspergillus flavus, Aspergillus fumigatus, Microsporum gypsum, and Fusarium oxysporum). The cytotoxicity of TNSAD was then tested against the HEp-2 cell line. Finally, the antifungal activity against Aspergillus fumigatus and Microsporum gypsum was assessed in vivo in a rat model. The in vitro results confirm the potency of TNSAD against fungi and its safety at a concentration of ≤ 5 mg/ml. In vivo results revealed that fungal cells were destroyed within the tissue when used systematically. we have described here a natural remarkable design that represents a potential antifungal agent and provided evidence for its efficiency and safety, which makes it a promising antifungal agent for the treatment of systemic and topical fungal infections.

Response of abundance, diversity, and network of rhizosphere fungal community to monoculture of cut chrysanthemum.

The effects of different monoculture years on rhizosphere fungal communities (abundance, diversity, structure, and cooccurrence network) of cut chrysanthemum were determined. Three different monoculture years were (i) planting for only 1year (Y1), (ii) continuous monoculture for 6years (Y6), and (iii) continuous monoculture for 12years (Y12). Compared to the Y1 treatment, the Y12 treatment significantly decreased the rhizosphere fungal gene copy numbers but increased the potential pathogen Fusarium oxysporum (P < 0.05). Both the Y6 and Y12 treatments significantly increased fungal diversity (Shannon and Simpson indices), but Y6 had great potential to enhance fungal richness (Chao1 index) relative to the Y12 treatment. Monoculture treatments decreased the relative abundance of Ascomycota but increased that of Mortierellomycota. Four ecological clusters (Modules 0, 3, 4, and 9) were observed in the fungal cooccurrence network across the Y1, Y6, and Y12 treatments, and only Module 0 was significantly enriched in the Y12 treatment and associated with soil properties (P < 0.05). RDA (redundancy analysis) and Mantel analysis showed that soil pH and soil nutrients (organic carbon, total nitrogen, and available phosphorus) were the key factors affecting fungal communities during monoculture of cut chrysanthemum. Overall, the changes in soil properties were responsible for shaping rhizospheric soil fungal communities in long-term rather than short-term monoculture systems. KEY POINTS: • Both short- and long-term monocultures reshaped the soil fungal community structure. • Long-term monoculture enhanced the network complexity of the fungal community. • Soil pH, C and N levels mainly drove modularization in the fungal community network.

Levering proteomic analysis of Pseudomonas fluorescens mediated resistance responses in tomato during pathogenicity of Fusarium oxysporum f. sp. oxysporum

The tomato, one of the world’s most extensively cultivated and consumed vegetable crops is negatively impacted by various pathogens. This study aimed to observe the differentially expressed proteins in tomato samples in plant–pathogen-biocontrol interactions. The fungal pathogen associated with wilted plants were isolated and identified based on its morphological and molecular characteristics. Fourteen strains of Pseudomonas fluorescens from agricultural soils were identified and described using biochemical assays, molecular analyses, and screening for antagonistic ability against the Fusarium wilt pathogen. Results demonstrated that the potential of P. fluorescens (TPf12) positively influenced the expression of antagonism against tomato wilt disease. A total of 14 proteins expressed differently were revealed in the 2D-PAGE-MS investigation. Proteins such as nucleoside diphosphate kinase, phenylalanine ammonia-lyase, protein kinase family protein, Ser/Thr protein kinase-like are unchanged in FOL pathogen interaction, but up-regulated in FOL + TPf12 treated roots, and lipid transfer-like protein, and phenylalanine ammonia-lyase were down-regulated in FOL infested roots and upregulated in FOL + TPf12 treated tomato roots. Phenylalanine ammonia-lyase protein expression is commonly found in TPf12 bioenriched roots, and FOL + TPf12 treated roots, indicating its role in response to the application of TPf12 in tomato. A GC–MS analysis was performed to detect the bioactive metabolites synthesized by TPf12. Molecular docking investigations were conducted using the maestro’s GLIDE docking module of the Schrodinger Software program. Among the secondary metabolites, Cyclohexanepropanoic acid, 2-oxo-, methyl ester (CAS), and 3-o-(4-o-Beta-D-Galactopyranosyl-Beta-D-Galactopyraosyl)-2-Acetylamino-2-Deoxy-D-Galactose were shown to be top-ranked with a least docking score against each differently expressed proteins. The profiled molecules expressed differently due to plant-pathogen-biocontrol interactions may be directly or incidentally involved in the wilt disease resistance of tomato plants.

Metabolomic profiling and its association with the bio-efficacy of Aspergillus niger strain against Fusarium wilt of guava.

Bio-control agents are the best alternative to chemicals for the successful management of plant diseases. The fungus Aspergillus niger is known to produce diverse metabolites with antifungal activity, attracting researchers to exploit it as a bio-control agent for plant disease control. In the present study, 11 A. niger strains were isolated and screened for their antagonism against the guava wilt pathogen under in vitro and in planta conditions. Strains were identified morphologically and molecularly by sequencing the internal transcribed spacer (ITS), β-tubulin, and calmodulin genes. The strains were evaluated through dual culture, volatile, and non-volatile methods under an in vitro study. AN-11, AN-6, and AN-2 inhibited the test pathogen Fusarium oxysporum f. sp. psidii (FOP) at 67.16%, 64.01%, and 60.48%, respectively. An in planta study was conducted under greenhouse conditions with 6 months old air-layered guava plants (var. Allahabad Safeda) by pre- and post-inoculation of FOP. The AN-11 strain was found to be effective under both pre- and post-inoculation trials. Furthermore, gas chromatography-mass spectrometry (GC-MS) analysis was carried out to characterize the volatile compounds of the most potential strain, A. niger. The hexane soluble fraction showed the appearance of characteristic peaks of hexadecenoic acid methyl ester (4.41%), 10-octadecanoic acid methyl ester (3.79%), dodecane (3.21%), undecane (3.19%), gibepyrone A (0.15%), 3-methylundecane (0.36%), and citroflex A (0.38%). The ethyl acetate fraction of the bio-control fungi revealed the occurrence of major antifungal compounds, such as acetic acid ethyl ester (17.32%), benzopyron-4-ol (12.17%), 1,2,6-hexanetriol (7.16%), 2-propenoic acid ethanediyl ester (2.95%), 1-(3-ethyloxiranyl)-ethenone (0.98%), 6-acetyl-8-methoxy dimethyl chromene (0.96%), 4-hexyl-2,5-dihydro dioxo furan acetic acid (0.19%), and octadecanoic acid (1.11%). Furthermore, bio-control abilities could be due to hyper-parasitism, the production of secondary metabolites, and competition for sites and nutrients. Indeed, the results will enrich the existing knowledge of metabolomic information and support perspectives on the bio-control mechanism of A. niger.

FonTup1 functions in growth, conidiogenesis and pathogenicity of Fusarium oxysporum f. sp. niveum through modulating the expression of the tricarboxylic acid cycle genes

The Tup1-Cyc8 complex is a highly conserved transcriptional corepressor that regulates intricate genetic network associated with various biological processes in fungi. Here, we report the role and mechanism of FonTup1 in regulating physiological processes and pathogenicity in watermelon Fusarium wilt fungus, Fusarium oxysporum f. sp. niveum (Fon). FonTup1 deletion impairs mycelial growth, asexual reproduction, and macroconidia morphology, but not macroconidial germination in Fon. The ΔFontup1 mutant exhibits altered tolerance to cell wall perturbing agent (congo red) and osmotic stressors (sorbitol or NaCl), but unchanged sensitivity to paraquat. The deletion of FonTup1 significantly decreases the pathogenicity of Fon toward watermelon plants through attenuating the ability to colonize and grow within the host. Transcriptome analysis revealed that FonTup1 regulates primary metabolic pathways, including the tricarboxylic acid (TCA) cycle, via altering the expression of corresponding genes. Downregulation of three malate dehydrogenase genes, FonMDH1–3, occurs in ΔFontup1, and disruption of FonMDH2 causes significant abnormalities in mycelial growth, conidiation, and virulence of Fon. These findings demonstrate that FonTup1, as a global transcriptional corepressor, plays crucial roles in different biological processes and pathogenicity of Fon through regulating various primary metabolic processes, including the TCA cycle. This study highlights the importance and molecular mechanism of the Tup1-Cyc8 complex in multiple basic biological processes and pathogenicity of phytopathogenic fungi.

A Novel Effector, FSE1, Regulates the Pathogenicity of Fusarium oxysporum f. sp. cubense Tropical Race 4 to Banana by Targeting the MYB Transcription Factor MaEFM-Like.

Phytopathogenic fungi secretes a range of effectors to manipulate plant defenses. Fusarium oxysporum f. sp. cubense tropical race 4 (Foc TR4) is a soil-borne pathogen that causes destructive banana wilt disease. Understanding the molecular mechanisms behind Foc TR4 effectors and their regulation of pathogenicity is helpful for developing disease control strategies. In the present study, we identified a novel effector, Fusarium special effector 1 (FSE1), in Foc TR4. We constructed FSE1 knock-out and overexpression mutants and investigated the functions of this effector. In vitro assays revealed that FSE1 was not required for vegetative growth and conidiation of Foc TR4. However, inoculation analysis of banana plantlets demonstrated that knock-out of FSE1 increased the disease index, while overexpression of FSE1 decreased it. Microscope analysis suggested that FSE1 was distributed in the cytoplasm and nuclei of plant cells. Furthermore, we identified an MYB transcription factor, MaEFM-like, as the target of FSE1, and the two proteins physically interacted in the nuclei of plant cells. In addition, Transient expression of MaEFM-like induced cell death in tobacco leaves. Our findings suggest that FSE1 is involved in the pathogenicity of Foc TR4 by targeting MaEFM-like.

Selection of rhizosphere communities of diverse rotation crops reveals unique core microbiome associated with reduced banana Fusarium wilt disease.

Crop rotation can assemble distinct core microbiota as functionally specific barriers against the invasion of banana Fusarium oxysporum pathogens. However, the taxonomic identity of rotation-unique core taxa and their legacy effects are poorly understood under field conditions. Pepper and eggplant rotations were employed to reveal rotation crop- and banana-unique antagonistic core taxa by insitu tracking of the soil microbiome assembly patterns for 2 yr. The rotation crop-unique antagonistic taxa were isolated and functionally verified by culture-dependent techniques, high-throughput sequencing, and pot experiments. Pepper and eggplant rotations resulted in eight and one rotation-unique antagonistic core taxa out of 12 507 microbial taxa, respectively. These nine antagonistic taxa were retained the following year and significantly decreased banana wilt disease incidence via legacy effects, although the cultivated strains were exclusively of the genera Bacillus and Pseudomonas. The fermentation broth and volatiles of these two taxa showed strong antagonistic activity, and pot experiments demonstrated high suppression of wilt disease and significant promotion of banana growth. Our study provides a mechanistic understanding of the identification of rotation crop-unique antagonistic taxa and highlights the importance of targeted cultivation of beneficial microorganisms for optimizing crop rotation-based scenarios in support of banana agriculture sustainability.

Isolation, Identification and Cultivation of Ganoderma spp. and Evaluation of Their Efficiency in Inhibiting Plant Pathogenic Fungi Fusarium oxysporum and Alternaria tenuissima

Fruit bodies of three Ganoderma isolates coded by Has.AA-6, Has.AA-7 and Has.AA-8 were collected from the trunks of Poplar, Sidr and Apricot trees, respectively, from some districts in Salah al-Din Governorate. It was phenotypically diagnosed to the genus level depending on the shapes, colors and sizes of the fruit bodies as well as the internal tissues and basidiospores. Molecular diagnoses to the species level was carried out depending on the percentage of identical 5.8S rRNA gene sequences with strains of fungi in the World Genetic Bank at the NCBI. Ganoderma isolates identified as G. applanatum Has.AA-6, G. lucidum Has.AA-7 and G. resinaceum Has.AA-8, and recorded in the World Genetic Bank at the NCBI under the accession number ON834523.1, ON834541.1 and ON834527.1, respectively. The results of cultivation of Ganoderma spp. showed a superiority of the biological efficiency of the corn cobs supplemented with wheat bran, which were 27.73, 31.27, 31.64 and 32.07%, compared to unsupplemented this medium, as the biological efficiency reached 26.18, 26.67, 27.21, 27.22, and 27.22% for G. lucidum, G. applanatum, G. resinaceum and G. resinaceum 1049 respectively. The role of the filtrate, mycelium biomass and fruit bodies of Ganoderma spp. against the pathogenic fungi F. oxysporum and A. tenuissima was studied, the results showed that the extracts of all Ganoderma spp. have a significant superiority in inhibiting the growth of both pathogenic fungi compared to the control treatment, the alcoholic extract of G. resinaceum fruit bodies recorded the highest inhibition of the F. oxysporum and A. tenuissima in which the colonies diameters reached 3.21 and 2.4cm, respectively, while G. lucidum gave the lowest colony diameter of F. oxysporum and A. tenuissima, which reached 2.61 and 2.25 cm, respectively, compared to with a diameter of 8.5 cm for colonies of both pathogenic fungi in the control.

First Report of Fusarium oxysporum f. sp. vasinfectum causing Fusarium Wilt of Cotton in Kansas, U.S.A.

Fusarium wilt is one of the most devastating diseases of cotton (Gossypium spp.). It is caused by the soil-borne pathogen Fusarium oxysporum Schlechtend. f. sp. vasinfectum (Atk.) Snyd. & Hans (Atkinson, 1892). To date, eight races of F. oxysporum f. sp. vasinfectum have been reported worldwide based on their diverse genetics and reactions to the host (Cianchetta, et al. 2015). Fusarium wilt symptoms appear at all developing stages. The fungus enters through the roots and colonizes the vascular system, leading to discoloration and wilting (Davis et al. 2006). During a survey in the July 2021 growing season, cotton plants showing typical wilting symptoms, stem discoloration, and root rot (Fig. 1A and B) were observed in two cotton fields in Sumner County, Kansas. In order to confirm the causal agent, root tissues and lower parts of the stems were collected from 25 diseased cotton plants and cleaned as previously described by Larren et al, (2001). Small segments (1-2 cm) of roots and stems were incubated on potato dextrose agar (PDA) at room temperature. The isolates were purified with the single spore method and 23 of 25 isolates (92%) showed typical morphology of F. oxysporum, with a white-peach pigmentation as reported previously (Leslie and Summerell 2008). Two isolates, CK13B and CK18A, one from each of the two fields were selected, and genomic DNA was extracted with E.Z.N.A Fungal DNA Mini kit (Omega Bio-tek, Norcross, GA). Polymerase chain reaction (PCR) assays were performed as reported previously (Ortiz, et al. 2017) to amplify and sequence a portion of three nuclear genes: translation elongation factor (EF-1α), phosphate: H* symporter (PHO), and β-tubulin (BT). BLASTn analysis of CK13B sequences showed 93-98% identity with F. oxysporum f. sp. vasinfectum isolates originating from Australia, with 93.43% (1706/1826 pb) identity of EF-1α to isolate AuSeed14 (KT323873), 95.11% (1849/1944 bp) of PHO to isolate AuK24232 (KT323909), and 97.56% (1840/1886 bp) identity of BT to isolate AusSeed14 (KT323833). Sequences of CK13B for EF1-α, PHO, and BT genes were submitted to GenBank, accession no. of ON754247, ON754248, and ON754249, respectively. The CK18A isolate showed high identity with F. oxysporum f. sp. vasinfectum races 1, 2, and 6 lineage isolates (Ortiz et al., 2017), with 99.89% (1822/1824 bp) identity of the EF1-α gene to isolate CDR238 (KT323838) from Arkansas, 98.36% (1916/1948 bp) identity of the PHO gene to isolate CDR1131 (KT323887) from Louisiana and 98.78% (1864/1887 bp) identity of the BT gene to isolate ATCC36198 (KT323799) from Brazil. Sequences of the CK18A isolate were submitted to GenBank, accession no. ON651444, ON725043, and ON725044, respectively. Pathogenicity of both isolates was tested on G. hirsutum as previously described (Kim et al. 2005) with three replicates per isolate and a control treatment in a growth chamber. Briefly, cotton seedlings were maintained with 12 h light/dark cycle at 25-20 °C. At the first true leaf stage seedlings were uprooted, roots were cleaned by rinsing with sterile water then placed in a conidial suspension (1×106 conidia/ml) for 2 h while the healthy control seedlings were dipped in water only. Plants were put into sterile soil, and the results were observed and recorded every seven days for a period of 30 days. The inoculated plants showed the same symptoms as those observed in the fields, wilting, leaf chlorosis, and necrosis. Both isolates were re-isolated from the roots of the inoculated plants. DNA was extracted and used for PCR with the specific gene primers as listed above. The sequences matched those of the original isolates, completing the Koch's pustulates. To our knowledge, this is the first report of F. oxysporum f. sp. vasinfectum causing Fusarium wilt disease of cotton in Kansas. These results will help growers select cultivars and design disease control strategies accordingly (Davis, et al., 2006). Further work is needed to determine the specific races in the area.

Productivity and mortality, of Fusarium oxysporum f. sp. passiflorae in passionfruit vines brs rubi do cerrado, grafted onto different rootstocks

The use of scions grafted onto passionfruit vines has become an alternative to their cultivation in areas with a history of fusariosis. However, the combinations between the graft and rootstock can influence on the productivity and longevity of the passionfruit farm. The objective was to evaluate the productivity and mortality of the passionfruit cv BRS Rubi do Cerrado grafted onto three species of rootstock in Terra Nova do Norte-MT. The design was a randomized block with 4 treatments BRS Rubi do Cerrado (BRS-RC) seedling plant along with those grafted onto three species of rootstock: Passiflora gibertii, Passiflora alata; Passiflora nitida. The scions were grafted through a cleft graft and the planting performed after 70 days. The evaluation was made of the total number and weight of the fruits, along with productivity and mortality of plants. Results showed that the BRS-RC, grafted onto P. gibertii and P. nitida, presented the best performance for weight of fruits, number of fruits and productivity. The cultivar that was grafted onto different rootstocks presented higher productivity in regards to the seedling plant. The BRS-RC, grafted onto P. nitida, presented a zero-mortality rate over the 16.5 months of cultivation. The rootstocks P. nitida and P. gibertii were superior to those of P. alata in reducing mortality in the passionfruit vine by Fusarium oxysporum f. sp. passiflorae. The confirmation was made of the pathogen Fusarium oxysporum f. passiflorae isolated in the experimental area in scions of the BRS-RC inoculated at 70 days of age.

Response of Microorganism Suspension and Various Kinds of Organic Fertilizers to the Development of Pathogen Fusarium sp. on Shallots

Shallot (Allium ascalonicum L) is one of the horticultural plants that acts as a natural antioxidant. Shallot's productivity in Indonesia is relatively low. It is influenced by various factors, one of which is due to the attack of a soil-borne pathogen, namely Fusarium oxysporum. Symptoms of Fusarium oxysporum pathogen attack are yellow or pale green leaves and more elongated growth. Severe attack leads plant to death. Balanced fertilization and biopesticides application can prevent Fusarium wilt. This study aims to reduce and control Fusarium wilt disease. The research method used was the Split Plot Design method which consisted of two factors with the main plot, namely the application of suspension of microorganisms (S) which consists of two levels, namely fungicide application (S0) and Fobio application and the sub-plot, namely the application of various organic fertilizers (M) which consists of three levels, namely control (chemical fertilizer) (M0), chicken manure (M1), and Piensbio organic fertilizer (M2). Observation data for each treatment will be analyzed using analysis of variance (ANOVA) followed by the Duncan test (alpha 5%) if there were differences in each treatment. The results of this study, the main plot treatment, fungicide application (S0), showed an incubation period of 29 days and an average intensity of disease attacks of 4.2%. The treatment of subplots, a type of organic fertilizer (M), is unable to suppress the intensity of the attack and slow down the incubation period of the Fusarium sp on shallot crops. There was no interaction between the treatment of the main plots and the subplots on all the observation parameters.

α-Tomatine degradation to tomatidine by food-related Aspergillus species belonging to the section Nigri.

α-Tomatine is a steroidal glycoalkaloid in tomato plants and degrades with ripening. The aglycone form, tomatidine, is reported to have beneficial effects. In this study, the ability of food-related microorganisms to produce tomatidine from α-tomatine was evaluated. Eleven strains of Aspergillus species belonging to the section Nigri exhibited tomatinase activity, and Aspergillus luchuensis JCM 22302 was selected for optimization due to its high activity in its mycelia, conidia, and non-mycotoxin-producing property. Next, using A. luchuensis JCM22302 conidia, the highest yield was obtained in a 24-h reaction with 50mM of acetic acid-sodium acetate buffer (pH 5.5) at 37 °C. Similar to the tomato pathogen Fusarium oxysporum f. lyceopersici, the time course analysis suggested that A. luchuensis JCM 22302 removed the entire sugar moiety in a single step. Future research will focus on utilizing conidia for large-scale tomatidine production because of their high tolerance and manageability.

Whole-genome sequencing reveals putative underlying mechanisms of biocontrol capability of IBFCBF-5

As the world’s food safety and environmental safety problems become increasingly severe, the agricultural sectors of various countries are also paying closer attention to the use of biofertilizers and biocontrol agents. Rhizosphere bacteria are a significant source of commonly used biofertilizers and biocontrol agents. This study aims to describe the genome and genomic traits of a biocontrol agent in the genus Bacillus. In this paper, a strain of Bacillus amyloliquefaciens IBFCBF-5 was isolated and identified to have an inhibitory effect on several common oomycete and fungal pathogens Phytophthora capsica, Sclerotinia sclerotiorum, Colletotrichum gloeosporioides, and Fusarium oxysporum f.sp. cucumerinum. The genome of strain IBFCB-5 was sequenced, and the assembled genome was 4,338,658 bp, with a G + C content of 46.05%. The IBFCBF-5 genome contains abundant GH, GT, CE, PL, AA, and CBM gene families, potentially degrading cellulose and hemicellulose, chitin, starch, xylan, peptidoglycan, etc. In addition, 14 lipopeptide and polypeptide antibiotic gene clusters were found in IBFCBF-5, including those coding for the synthesis of several known antifungal and antibacterial compounds Fengycin, Bacilysin, Bacillibactin, and Plantazolicin. Our results show that Bacillus amyloliquefaciens IBFCBF-5 has a broad-spectrum antifungal ability and that its genome contains many genes coding for enzymes involved in the synthesis of antimicrobial metabolites.

Pathogenic fungi neutralize plant‐derived ROS via Srpk1 deacetylation

In response to infection, plants can induce the production of reactive oxygen species (ROS) to restrict pathogen invasion. In turn, adapted pathogens have evolved a counteracting mechanism of enzymatic ROS detoxification, but how it is activated remains elusive. Here, we show that in the tomato vascular wilt pathogen Fusarium oxysporum f. sp. lycopersici (Fol) this process is initiated by deacetylation of the FolSrpk1 kinase. Upon ROS exposure, Fol decreases FolSrpk1 acetylation on the K304 residue by altering the expression of the acetylation‐controlling enzymes. Deacetylated FolSrpk1 disassociates from the cytoplasmic FolAha1 protein, thus enabling its nuclear translocation. Increased accumulation of FolSrpk1 in the nucleus allows for hyperphosphorylation of its phosphorylation target FolSr1 that subsequently enhances transcription of different types of antioxidant enzymes. Secretion of these enzymes removes plant‐produced H2O2, and enables successful Fol invasion. Deacetylation of FolSrpk1 homologs has a similar function in Botrytis cinerea and likely other fungal pathogens. These findings reveal a conserved mechanism for initiation of ROS detoxification upon plant fungal infection.

Nanomaterial Size and Surface Modification Mediate Disease Resistance Activation in Cucumber (Cucumis sativus).

Crop disease represents a serious and increasing threat to global food security. Lanthanum oxide nanomaterials (La2O3 NMs) with different sizes (10 and 20 nm) and surface modifications (citrate, polyvinylpyrrolidone [PVP], and poly(ethylene glycol)) were investigated for their control of the fungal pathogen Fusarium oxysporum (Schl.) f. sp cucumerinum Owen on six-week-old cucumber (Cucumis sativus) in soil. Seed treatment and foliar application of the La2O3 NMs at 20-200 mg/kg (mg/L) significantly suppressed cucumber wilt (decreased by 12.50-52.11%), although the disease control efficacy was concentration-, size-, and surface modification-dependent. The best pathogen control was achieved by foliar application of 200 mg/L PVP-coated La2O3 NMs (10 nm); disease severity was decreased by 67.6%, and fresh shoot biomass was increased by 49.9% as compared with pathogen-infected control. Importantly, disease control efficacy was 1.97- and 3.61-fold greater than that of La2O3 bulk particles and a commercial fungicide (Hymexazol), respectively. Additionally, La2O3 NMs application enhanced cucumber yield by 350-461%, increased fruit total amino acids by 295-344%, and improved fruit vitamin content by 65-169% as compared with infected controls. Transcriptomic and metabolomic analyses revealed that La2O3 NMs: (1) interacted with calmodulin, subsequently activating salicylic acid-dependent systemic acquired resistance; (2) increased the activity and expression of antioxidant and related genes, thereby alleviating pathogen-induced oxidative stress; and (3) directly inhibited in vivo pathogen growth. The findings highlight the significant potential of La2O3 NMs for suppressing plant disease in sustainable agriculture.