Control Of Fusarium Wilt Research Articles

Controlling Tobacco Diseases: An Overview of Black Shank and Fusarium Wilt

Black shank, caused by Phytophthora nicotianae, and Fusarium wilt, caused by the Fusarium oxysporium f. sp. nicotianae, are major diseases affecting tobacco crops globally. Phytophthora nicotianae is primarily found in tropical and subtropical regions and infects tobacco plants by producing zoospores that swim to root tissue and form cysts. Symptoms of black shank include root and crown rot, wilting, leaf chlorosis, stem lesions, and pith necrosis. Management strategies for black shank include cultural practices, chemical treatments, and host resistance. Chemical fungicides, such as metalaxyl or mefenoxam, oxathiapiprolin, and fluopicolide, can be used but there is a risk of fungicide resistance. Fusarium wilt is characterized by yellowing, drying, and death of leaves, leading to the death of the entire plant. Control measures for Fusarium wilt include plant resistance, cleanliness, crop rotation, nutrition, nematode management, and fumigation or biofumigation. The most successful control of Fusarium wilt has been through the use of resistant tobacco cultivars. The impact of rotation crops and resistant plants on the pathogen populations in the soil must be evaluated and soil pH and calcium levels may also impact the disease. The presence of the fungus in a field can last for several years without a vulnerable host. Int. J. Appl. Sci. Biotechnol. Vol 11(1): 1-7.

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.

Endophytic bacteria as biological agents to control fusarium wilt disease and promote tomato plant growth

Plant endophytic bacteria are symbiotic bacteria that live in plant tissues and may play a role in disease control and/or plant growth promotion. In this study, six plant endophytic bacterial isolates, Arthrobacter sp. AM08, Pseudomonas aeruginosa AJ14, P. mosselii AB06, Bacillus cereus AP12, B. thuringiensis AK08 and Serratia marcescens AS09, were tested for their ability to control Fusarium oxysporum f. sp. lycopersici (FOL) and to promote the growth of tomato plant. The isolates were evaluated for their ability to produce hydrolytic enzymes (cellulase, protease and chitinase), hydrogen cyanide (HCN), indole 3-acetic acid (IAA), 1-aminocyclopropane 1-carboxylic acid (ACC) deaminase, and siderophores. The activity of cellulase, protease and chitinase enzymes was detected in all the isolates studied, whereas the highest HCN activity was observed in P. aeruginosa. The activity of IAA, ACC deaminase, and siderophore was also observed in all isolates, with B. cereus, P. mosselii, and S. marcescens being the highest producers of IAA and B. thuringiensis being the highest producer of siderophores. All isolates produced ACC deaminase at almost the same level. Application of the isolates to tomato seeds prolonged FOL incubation time, reduced disease incidence, and shortened xylem discoloration length compared to the controls, confirming the ability of the isolates to control FOL. In addition, all tested isolated showed plant growth promoting activity, as indicated by increased plant height and root length. The study showed that the endophytic bacteria are capable of controlling FOL and promoting the growth of tomato plant, revealing their potential to be developed as biocontrol agents.

Rhizospheric-Derived Nocardiopsis alba BH35 as an Effective Biocontrol Agent Actinobacterium with Antifungal and Plant Growth-Promoting Effects: In Vitro Studies.

The biocontrol approach using beneficial microorganisms to control crop diseases is becoming an essential alternative to chemical fungicides. Therefore, new and efficient biocontrol agents (BCA) are needed. In this study, a rhizospheric actinomycete isolate showed unique and promising antagonistic activity against three of the most common phytopathogenic fungi, Fusarium oxysporum MH105, Rhizoctonia solani To18, and Alternaria brassicicola CBS107. Identification of the antagonistic strain, which was performed according to spore morphology and cell wall chemotype, suggested that it belongs to the Nocardiopsaceae. Furthermore, cultural, physiological, and biochemical characteristics, together with phylogenetic analysis of the 16S rRNA gene (OP869859.1), indicated the identity of this strain to Nocardiopsis alba. The cell-free filtrate (CFF) of the strain was evaluated for its antifungal potency, and the resultant inhibition zone diameters ranged from 17.0 ± 0.92 to 19.5 ± 0.28 mm for the tested fungal species. Additionally, the CFF was evaluated in vitro to control Fusarium wilt disease in Vicia faba using the spraying method under greenhouse conditions, and the results showed marked differences in virulence between the control and treatment plants, indicating the biocontrol efficacy of this actinomycete. A promising plant-growth promoting (PGP) ability in seed germination and seedling growth of V. faba was also recorded in vitro for the CFF, which displayed PGP traits of phosphate solubilization (48 mg/100 ml) as well as production of indole acetic acid (34 μg/ml) and ammonia (20 μg/ml). This study provided scientific validation that the new rhizobacterium Nocardiopsis alba strain BH35 could be further utilized in bioformulation and possesses biocontrol and plant growth-promoting capabilities.

Wheat–faba bean intercropping can control Fusarium wilt in faba bean under F. commune and ferulic acid stress as revealed by histopathological analysis

Fusarium wilt, is an important soilborne disease restricting the cultivation of faba bean. Wheat–faba bean intercropping is one of the useful means to control Fusarium wilt in faba bean. In this study, we analyzed the histopathological effect of wheat–faba bean intercropping system on Fusarium wilt in faba bean under F. commune and ferulic acid stress. Faba bean was inoculated with F. commune. Various concentrations of ferulic acid were added to the inoculated plants to study the occurrence of Fusarium wilt, growth of faba bean seedlings, activity of cell-wall-degrading enzymes (CWDEs) produced by F. commune in stems, and structural changes in stem tissues under monocropping and intercropping systems. When ferulic acid was added to the faba bean plants inoculated with F. commune, wheat–faba bean intercropping significantly reduced the activity of CWDEs. Microstructure observation revealed that the xylem vessel was thickened, and xylem parenchymal tissue and vascular cambium produced gelatinous substance and tylose. Moreover, callose deposition was reduced in the sieve tube; death rate of vascular tissue, cortex tissue, and epidermis tissue was reduced, and faba bean biomass was observably increased. The combination of these factors reduced the occurrence of Fusarium wilt. Therefore, wheat–faba bean intercropping reduced the severity of Fusarium wilt in faba bean by decreasing the activities of CWDEs and increasing tissue structure integrity.

A Field Evaluation of Sodium Silicate and Bacillus subtilis on the Growth and Yield of Bananas following Fusarium Wilt Disease Infection

A field investigation was conducted in a Fusarium-infected area to evaluate the effectiveness of silicate compounds with antagonist bacteria on morpho-physiological growth performance in bananas. The roots of banana plants were treated by drenching the soil with four different treatments: control (without any treatment), CBZ (Carbendazim fungicide alone), SS + BS (integration sodium silicate with Bacillus subtilis), and CBZ + SS + BS (integration CBZ, SS, and BS). All treatments were arranged in a randomized complete block design with four replications. The results confirm that plant height, pseudo-stem diameter, and canopy diameter markedly increased from weeks 2 to 10 after transplantation. Amendment with these elements induced a higher total chlorophyll content, which contributed to the increased rate of leaf gas exchange and biochemical changes for controlling Fusarium wilt disease infection. From these findings, the CBZ + SS + BS application in the farm had significantly reduced disease incidence by 16.07% and disease severity by 14.28%. The same treatment achieved the greatest disease reduction by 63.05%. Therefore, the integration between CBZ + SS + BS had good significant effects in controlling Fusarium wilt disease and enhanced the morpho-physiological growth performance with an average yield production of about 24.72 kg per fruit bunch.

Karakter Morfologi Genotipe Jarak Kepyar (Ricinus communis L.) Tahan Penyakit Layu Fusarium

The castor bean (Ricinus communis L.) is a plant with a lot of potential as a vegetable oil producer. Castor bean productivity in Indonesia was 1.36 thousand tons in 2013, but it fell to 1.30 thousand tons in 2014. Fusarium wilt is one of the challenges in increasing castor bean production. Resistant genotypes can be used to control Fusarium wilt in an environmentally friendly manner. The goal of this study was to determine the variability and superior performance of Fusarium wilt-resistant castor beans. The study took place at the Faculty of Agriculture's greenhouse Experimental farm, Universitas Brawijaya in Lowokwaru District, Malang, East Java, from January to July 2021. Twenty two genotypes resistant to Fusarium wilt, urea fertilizer, NPK, and pesticides were used. Augmented design was used as the experimental field design. Following Pearson correlation type and coefficient of variation, variability was investigated using principal component analysis (PCA). Based on PCA, the variability of morphological characters of 22 genotypes of castor bean is divided into first-nine principal components with a cumulative variability of 85.91 percent. The coefficient of variation for the main raceme weight character is 61.15 percent. The TBN 0816-36 genotype succeeds in vegetative characters, while the CT4-10-3-(C864-3)-68 genotype performs best in yield.

Faba bean–wheat intercropping and appropriate nitrogen supply control fusarium wilt in faba bean via altering specific amino acids in the root exudate of faba bean

With the increased continuous cropping of faba bean (Vicia faba L.), the incidence rate of Fusarium wilt in faba bean is increasing. The application of nitrogen fertilizer and intercropping of faba bean and wheat can affect the occurrence of the disease. In the field experiment, the effect of nitrogen fertilizer and faba bean - wheat intercropping on the occurrence of Fusarium wilt in faba bean was explored and the contents of 12 amino acids in the root exudate of faba bean were determined in a hydroponic experiment. Exudation amounts of seven amino acids were affected significantly. These were selected for an indoor culture experiment, and the effects of various concentrations of amino acids on the growth, reproduction, and pathogenicity of F. oxysporum f. sp. fabae (FOF) was studied. At 90 kg N ha−1, wheat-faba bean intercropping increased the content of in the root exudate of faba bean Ser, Glu, Tyr, and Lys which also inhibited the growth and reproduction of FOF while the content of Asp, Val, and Pro was reduced. The latter promoted the growth and reproduction of FOF. These results suggest, that changes in exudation patterns contribute to the observed reduction in the occurrence of Fusarium wilt in faba bean through intercropping and reduction of nitrogen input in the field. Optimum reduced N-applications combined with species mixtures should be identified and included in agricultural management.

Waktu Aplikasi Trichokompos dan Larutan Kelakai dalam Menentukan Kejadian Penyakit Layu Fusarium pada Tanaman Padi Beras Merah (Oryza nivara L.)

Brown rice (Oryza nivara L.) is increasingly being cultivated along with the increasing needs of the community, such as health therapy using natural ingredients. One of the main diseases that attack brown rice is Fusarium wilt. Biological agents are an alternative control that is environmentally friendly and safe. The use of Trichocompost and Kelakai solution is an alternative that has the potential to control Fusarium wilt in brown rice plants. The aim of this study was to find out how long it took for the disease to appear in the red rice seedbeds after trichocompost and a solution of LALAI were applied. Six treatments and four replications were used in this study using a completely randomized design. The findings in this study indicated that trichocompost and lacteal solution prevented the development of Fusarium wilt in brown rice, the application time which suppressed disease development was application one week before planting and during transplanting. The application of trichocompost treatment and Lakalai solution was also proven to be able to extend the incubation period of the pathogen by 16.20 DAI when compared to plants without treatment at 9.80 DAI

Integrated Application of Salicylic Acid and PGPRs to Control Fusarium Wilt of Chickpea

Fusarium wilt and Ascochyta blight are the most important diseases of chickpea. The current study was designed to investigate the individual and combined effect of salicylic acid (SA) with Pseudomonas stutzeri and Pseudomonas putida to suppress Fusarium wilt and promote growth of chickpea varieties: Thal-2006 and Punjab-2008. At the time of sowing, inoculum of Fusarium oxysporum was applied to the soil and the incidence of Fusarium wilt was recorded after 60 days. The seeds were inoculated with Pseudomonas stutzeri and Pseudomonas putida prior to sowing. Chickpea plants were treated with salicylic acid at seedling stage. The combination of P. stutzeri and SA significantly increased root length (166% and 145%), shoot height (50% and 47%) and shoot biomass (300% and 233%) in cv. Thal-2006 and cv. Punjab-2008, respectively, in infected plants. Similarly, the combined treatment of P. putida + SA, also enhanced the plant growth parameters of chickpea varieties. Maximum reduction in disease severity was observed in both P. stutzeri + SA (90% and 84%) and P. putida + SA (79% and 77%) treatments in cv. Thal-2006 and Punjab-2008, respectively. Both P. putida + SA and P. stutzeri + SA treatments resulted in increased leaf relative water and total protein content, peroxidase, superoxide dismutase, phenylalanine ammonia-lyase and polyphenol oxidase activities in both resistant (cv. Thal-2006) and susceptible (cv. Punjab-2008) cultivars. Both treatments also significantly reduced malondialdehyde (MDA) and proline content in cv. Thal-2006 and Punjab-2008. Cultivar Thal-2006 was more effective than cv. Punjab-2008. The results suggested that, in combination, salicylic acid and P. stutzeri may play an important role in controlling Fusarium wilt diseases by inducing systemic resistance in chickpea.

The SUMOylation Pathway Components Are Required for Vegetative Growth, Asexual Development, Cytotoxic Responses, and Programmed Cell Death Events in Fusarium oxysporum f. sp. niveum.

SUMOylation is an essential protein modification process that regulates numerous crucial cellular and biochemical processes in phytopathogenic fungi, and thus plays important roles in multiple biological functions. The present study characterizes the SUMOylation pathway components, including SMT3 (SUMO), AOS1 (an E1 enzyme), UBC9 (an E2 enzyme), and MMS21 (an E3 ligase), in Fusarium oxysporum f. sp. niveum (Fon), the causative agent of watermelon Fusarium wilt, in terms of the phylogenetic relationship, gene/protein structures, and basic biological functions. The SUMOylation components FonSMT3, FonAOS1, FonUBC9, and FonMMS21 are predominantly located in the nucleus. FonSMT3, FonAOS1, FonUBC9, and FonMMS21 are highly expressed in the germinating macroconidia, but their expression is downregulated gradually in infected watermelon roots with the disease progression. The disruption of FonUBA2 and FonSIZ1 seems to be lethal in Fon. The deletion mutant strains for FonSMT3, FonAOS1, FonUBC9, and FonMMS21 are viable, but exhibit significant defects in vegetative growth, asexual reproduction, conidial morphology, spore germination, responses to metal ions and DNA-damaging agents, and apoptosis. The disruption of FonSMT3, FonAOS1, FonUBC9, and FonMMS21 enhances sensitivity to cell wall-perturbing agents, but confers tolerance to digestion by cell wall-degrading enzymes. Furthermore, the disruption of FonSMT3, FonAOS1, and FonUBC9 negatively regulates autophagy in Fon. Overall, these results demonstrate that the SUMOylation pathway plays vital roles in regulating multiple basic biological processes in Fon, and, thus, can serve as a potential target for developing a disease management approach to control Fusarium wilt in watermelon.

Biochar combined with Bacillus subtilis SL-44 as an eco-friendly strategy to improve soil fertility, reduce Fusarium wilt, and promote radish growth

Bacillus subtilis as microbial fertilizers contribute to avoiding the harmful effects of traditional agricultural fertilizers and pesticides. However, there are many restrictions on the practical application of fertilizers. In this study, microbial biochar formulations (BCMs) were prepared by loading biochar with B. subtilis SL-44. Pot experiments were conducted to evaluate the effects of the BCMs on soil fertility, Fusarium wilt control, and radish plant growth. The application of BCMs dramatically improved soil properties and favored plant growth. Compared with SL-44 and biochar treatments, the BCMs treatments increased radish plant physical-chemical properties and activities of several enzymes in the soil. What’s more, Fusarium wilt incidence had decreased by 59.88%. In addition, the BCMs treatments exhibited a significant increase in the abundance of bacterial genera in the rhizosphere soil of radish. Therefore, this study demonstrated that BCMs may be an eco-friendly strategy for improving soil fertility, reducing Fusarium wilt, and promoting radish plant growth.

Effect of antagonistic bacteria and its formulation to control fusarium wilt disease on shallot

Biocontrol of pathogenic fungi using antagonistic bacteria isolated from the soil (rhizosphere) is expected to suppress plant diseases to obtain good quality of yield, and thus support sustainable agriculture. The study aimed to formulate and scale up the production of rhizosphere-based bacterial biopesticides that effective in suppressing the onset of Fusarium wilt disease caused by Fusarium oxysporum f.sp. cepae on shallot. The experiment to evaluate the effectiveness of biocontrol agents against Fusarium wilt disease was carried out employing shallot cv. ‘bima curut’ in the field (Patrol-Indramayu,West Java), from May to August 2018 growing season. The experimental plot of 1.20 m x 18 m, was prepared using plant spacing of 15 × 10 cm. The solid formulation of kaolin-based bacteria (containing bacterial cells of 109 CFU/mL) was applied with variation of four concentrations range from 0.3125 to 2.5 mL/L. The experiment was arranged in randomized block design with four replications. Shallot beginning at 30 days old-plant was sprayed three times at one-week intervals. The results showed that the disease intensity was significantly lower than in control. Under natural infection, the spraying application of a bacterial isolate (DSB2) using kaolin formulation (107 CFU/mL) with a formula concentration of 1.25 mL/L could reduce the disease intensity. Tuber yield of formula treatments was significantly higher than that of control. Thus, the use of bacterial formula as environmental-friendly biocontrol agent in this study might be further recommended in controlling Fusarium wilt disease on shallots.

Revealing the Mechanisms for Linalool Antifungal Activity against Fusarium oxysporum and Its Efficient Control of Fusarium Wilt in Tomato Plants

Fusarium oxysporum f. sp. radicis-lycopersici (Forl) is a destructive soil-borne phytopathogenic fungus that causes Fusarium crown and root rot (FCRR) of tomato, leading to considerable field yield losses. In this study, we explored the antifungal capability of linalool, a natural plant volatile organic component, against Forl and its role in controlling FCRR symptoms in tomatoes. Our results showed that Forl mycelial growth was inhibited by the linalool treatment and that the linalool treatment damaged cell membrane integrity, enhanced reactive oxygen species levels, depleted glutathione, and reduced the activities of many antioxidant enzymes in Forl. Transcriptomic and proteomic analyses demonstrated that linalool also downregulated metabolic biosynthetic pathways at the transcript and protein levels, including redox, transporter activity, and carbohydrate metabolism in Forl. Moreover, linalool significantly decreased the expression of many Forl pathogenic genes, such as cell wall degrading enzymes (CWDEs) and G proteins, which is likely how a Forl infection was prevented. Importantly, exogenously applied linalool activated the salicylic acid (SA) and jasmonic acid (JA) defensive pathways to improve disease resistance and relieved the negative effects of Forl on plant growth. Taken together, we report that linalool is an effective fungicide against Forl and will be a promising green chemical agent for controlling FCRR.

Construction of a compound microbial agent for biocontrol against Fusarium wilt of banana.

Banana wilt caused by Fusarium oxysporum f. sp. cubense has devastated a large number of banana plantations worldwide. Biological control is a possible method to conquer this disease. However, the control effect was often low and unstable while a single biocontrol strain had been applied in the field. Therefore, this study aimed to construct an effective compound microbial agent to control Fusarium wilt of banana (FWB) in the field. In addition to it, the compounding strategy of combining single strains for improving the control effect was investigated. Based on the compatibility test, five representative biocontrol strains were selected for the combination of all possible permutations. The pot experiment indicated that every biocontrol strain and their 26 combinations could control FWB to varying degrees. The control effect of combinations on FWB was higher than that of a single strain. In terms of the number of combinatorial biocontrol strains, the control effect of the four-strain combinations was the highest. According to the taxonomic differences of the five biocontrol strains, 26 biocontrol strain combinations could be divided into four groups. Among the strains in the combination, the larger the taxonomic differences the more easily it was to obtain a higher control effect. To obtain stable and efficient combinations, eight combinations were selected out and evaluated for their effectiveness in controlling FWB in different type soil. Compared with the other seven combinations, the four-strain combination T28 (Pt05 + Bc11 + Ba62 + gz-2) got the highest and stablest control effect in the four types of soil in greenhouse. And then the control effect of combination T28 was evaluated in field conditions, compared with commercially agents Bacillus subtilis, Trichoderma harzianum, and carbendazim. After four consecutive applications in the field, the control effect of T28 against FWB was the highest, reaching 57.14%. The results showed that combination T28 had a good application prospect, and the finding provided a reference for the construction of compound microbial agents.

Fluorine-containing amphiphilic quaternary ammonium salts for the suppression of Banana fusarium wilt

As the pathogen of banana Fusarium wilt, Fusarium oxysporum f. sp. cubense race 4 (Foc4) has the strongest toxicity and pathogenicity due to its long-term viability in soil, but there is still no effective way to control it at present. Based on the activity parameters of polymeric quaternary ammonium salt in our previous work, this paper hopes to enhance the amphiphilicity of polymeric quaternary ammonium salt by introducing a fluoroalkyl group to improve the antifungal property of polymeric quaternary ammonium salt and achieve stable adsorption and long-term inhibition of saprophytic Foc4 conidia in soil. Here, we prepared a series of fluorine-containing ammonium salts with random and block structures by atom transfer radical polymerization (ATRP), and we systematically studied the effects of the introduction of fluoroalkyl groups, the proportion of hydrophobic segments and polymer structure on micelle properties, antifungal properties, adsorption, migration and long-term antifungal properties against Foc4 in soil. Finally, the preferred polymeric quaternary ammonium salts were selected for pot experiments in the prevention and control of banana Fusarium wilt caused by Foc4, and positive experimental results were achieved. In conclusion, we made an exploratory attempt at the practical application of polymeric amphiphilic quaternary ammonium salt in plant disease control.

Extraction and characterization of cyclic lipopeptides with antifungal and antioxidant activities from Bacillus amyloliquefaciens.

This study aimed to isolate active substances from metabolites of Bacillus amyloliquefaciens SJ100001 and examine their antifungal activity against Fusarium oxysporum (F. oxysporum) SJ300024 screened from the root-soil of cucumber wilt. An active substance, anti-SJ300024, was obtained from the fermentation broth of strain SJ100001 by reversed-phase silica gel and gel chromatography, and further got its chemical structure as cyclic lipopeptide Epichlicin through nuclear magnetic resonance (NMR) and mass spectrometry (MS). In vitro experiments showed that Epichlicin had a better inhibitory rate (67.46%) against the strain SJ300024 than the commercially available fungicide hymexazol (45.10%) at the same concentration. The MTT assays proved that Epichlicin was non-cytotoxic, besides it also had good free radical scavenging ability and total reducing ability. Epichlicin isolated from strain SJ100001 can effectively control F. oxysporum SJ300024 screened from the root-soil of cucumber wilt. Epichlicin may be used as an environmentally friendly and efficient biocontrol agent for controlling Fusarium wilt of cucumber and reducing crop losses. More importantly, the non-cytotoxicity of Epichlicin can avoid harm to consumers. Additionally, Epichlicin has broad application prospects in medicine due to its antioxidant properties.

Optimization of biosurfactant production by Pseudomonas aeruginosa using rice water and its competence in controlling Fusarium wilt of Abelmoschus esculentus

• Rice water was selected as the cheapest carbon source for formulating rice water medium in order to optimize biosurfactant synthesis by Pseudomonas aeruginosa . • The in vitro and in vivo antifungal efficacy and biocontrol strategy of the biosurfactant against Fusarium wilt of Abelmoschus esculentus were demonstrated. • The identification of the rhl gene, TLC, FT-IR, HPLC, and GC–MS analyses suggested the biosurfactant was rhamnolipid. • The biosurfactant that has been produced will aid in large-scale commercialization and will replace the usage of chemical surfactants in agricultural wastes. Biosurfactants, in comparison to chemical surfactants, have a greater impact on various applications due to their stability, degradability, and other physicochemical characteristics. Increasing yield and lowering production costs are critical to enhancing biosurfactant efficiency. Because biosurfactant production costs are determined by the least expensive substrate, agro-based industrial waste is one of the most promising economic strategies. Therefore, in this study we aimed to achieve the biosurfactant production in Pseudomonas aeruginosa by low cost rice medium using Response surface methodology (RSM) and assessed their competence in controlling the Fusarium wilt of Abelmoschus esculentus . Initially, the selected strain P. aeruginosa PBS29 was confirmed using 16S rRNA sequencing. Then, the 20% (v/v) of rice water was chosen as the cheapest carbon source for formulating rice water medium to optimize biosurfactant production using Central Composite Design. Enhanced biosurfactant yield of 9.35 g/l was attained through RSM by 0.59 fold higher than preliminary analysis. The model was significant with a regression coefficient of 0.98. The optimal condition was identified as 1.18% (w/v) nitrogen source [glutamic acid], pH 6.8, temperature at 37.4 °C, 2.5% (v/v) inoculum size, and 167.9 rpm agitation. In-vitro antifungal activity and biocontrol strategy of the biosurfactant demonstrated against Fusarium wilt of Abelmoschus esculentus at 100 μg/ml concentration by both soil drenching and foliar spray by pot trial. Furthermore, the detection of rhl gene, TLC, FT-IR, HPLC and GC–MS analyses suggested that the biosurfactant is rhamnolipid. Overall, in this study, the biosurfactant was synthesized using inexpensive rice water and substantiated its safe use as a biocontrol agent, which will help large-scale commercialization and interchange chemical surfactant used in agricultural wastes.

Dissection of leucine-rich repeat receptor-like protein kinases: insight into resistance to Fusarium wilt in tung tree.

The tung tree is a woody oil plant native to China and widely distributed in the subtropics. The three main species commonly known as Vernicia are V. fordii, V. montana, and V. cordata. The growth and development of V. fordii are affected by a large number of plant pathogens, such as Fusarium wilt caused by Fusarium sp. In contrast, V. montana shows significant resistance to Fusarium wilt. The leucine-rich repeat receptor-like protein kinase (LRR-RLK) is the largest class of receptor-like kinases associated with plant resistance to Fusarium wilt. Here, we identified 239 VmLRR-RLKs in V. montana, and found that there were characteristic domains of resistance to Fusarium wilt in them. Phylogenetic analysis suggested that the VmLRR-RLKs are divided into 14 subfamilies, indicating that homologous genes in the same group may have similar functions. Chromosomal localization analysis showed that VmLRR-RLKs were unevenly distributed on chromosomes, and segment duplications were the main reason for the expansion of VmLRR-RLK family members. The transcriptome data showed that six orthologous pairs were up-regulated in V. montana in response to Fusarium wilt, while the corresponding orthologous genes showed low or no expression in V. fordii in resistance Fusarium wilt, further indicating the important role of LRR-RLKs in V. montana's resistance to infection by Fusarium spp. Our study provides important reference genes for the future use of molecular breeding to improve oil yield and control of Fusarium wilt in tung tree.

Efficiency and mechanisms of action of pelletized compost loaded with Bacillus velezensis CE 100 for controlling tomato Fusarium wilt

The objective of this study was to determine the control efficacy of pelletized compost containing high number of the biocontrol agent, Bacillus velezensis CE 100, for tomato Fusarium wilt. Pelletizing had no serious effects on the cell numbers and quality of strain CE 100 in producing lytic enzymes although antifungal activities of reisolated strain CE 100 from pellet against Fusarium oxysporum f. sp. lycopersici was slightly reduced compared to the original strain. However, culture filtrates of two B. velezensis CE 100 strains not only induced abnormal mycelial development with pigment reduction but also caused hyphal deformations with swelling and bugling of the fungal pathogen. Moreover, cyclo(prolyl-valyl), an antifungal dipeptide, was isolated from B. velezensis CE 100 culture and identified by HR-ESI-MS and 1D- and 2D-NMR experiments. The dipeptide limited conidial germination of F. oxysporum f. sp. lycopersici in a concentration-dependent pattern. Long incubation period triggered irregular hyphal morphologies with swollen septa and disorganized cell contents in treatments with the dipeptide. Under in vivo conditions, supplementation of soil with strain CE 100-pelletized compost significantly controlled Fusarium wilt and resulted in the lowest disease incidence rate, consequently promoting tomato growth. The soil amendment with strain CE 100-pelletized compost could be used as a potential approach for a better fungal disease control, promoting sustainable agriculture.