Induction of Twisting Disease Resistance on Shallot (Allium cepa var. ascalonicum) Against Twisting Disease (Fusarium oxysporum f. sp. cepae) through Biopesticide Application

This study aimed to develop resistance in shallot (Allium cepa) against twisting disease caused by Fusarium oxysporum by applying microorganism-based biopesticides. By inducing resistance in shallots, the research sought to explore the pathogen-host interactions, understand infection mechanisms, and establish sustainable disease management strategies. Utilizing a biopesticide approach within an organic farming framework, this study aimed to assess the effectiveness of biopesticides in inducing plant defense mechanisms. The experimental design was non-factorial and followed a randomized block structure, consisting of four treatments with three replications each: (A) Chemical pesticide and fertilizer, (B) Biopesticide applied to seeds and plants, with chemical fertilizers on soil, (C) Soil sterilization with biopesticide and pesticide application on plants, and (D) Soil sterilization with biopesticide, with biopesticide applied to seeds and plants. Observations focused on disease intensity and salicylic and jasmonic acid levels in shallot bulbs. Results demonstrated that biopesticide application successfully reduced disease incidence and increased resistance, as shown by higher levels of salicylic and jasmonic acids in treated plants. The study concluded that biopesticides are promising for enhancing systemic resistance in shallots

In vitro evaluation of the effect of combined indigenous antagonistic bacteria against Fusarium oxysporum

This study aimed to evaluate the potential of combined indigenous antagonistic bacteria against Fusarium oxysporum f.sp. cepae by in vitro. These bacteria were originated from coffee plant litter in UB Forest and already known their ability as a single biocontrol against F. oxysporum. The research was conducted at the Plant Disease Laboratory, Department of Plant Pests and Diseases, Brawijaya University. The methods consisted of isolate preparation, pathogenicity test and in vitro antagonistic test using a modified multiple culture method. The study was conducted with eight treatments and four replications.  Based on this study, there were four best treatments in inhibiting the mycelia growth of F. oxysporum more than 50% compared to the control. The highest inhibitory was Bacillus mycoides and Alcaligenes faecalis which were able to inhibit F. oxysporum up to 67,46%. This study proves the potential of a new combination of indigenous antagonistic bacteria to inhibit fusarium wilt disease

Characterization of Fungal Communities Associated to Willow SRIC Plantations in the Canadian Prairies Ecozone Using PCR-Based Molecular Methods

Willow (Salix spp.), a major source of biomass and renewable fiber production, is one of the best choices for short-rotation intensive culture (SRIC) in Canada. Since fungal communities play important roles in the plant’s health status, it is vital to understand their interactions with willows and their roles in the sustainability of SRIC. In this study, fungal diversity of the above-ground organs (stem/leaf) of healthy and diseased willow plants in western Canadian Prairies were assessed using cultural and PCR-denaturing gradient gel electrophoresis (DGGE) techniques. Comparison of the mycoprofiles within established plantations vs. newly introduced cuttings revealed differences in the fungal communities. Ascomycota were mainly isolated, followed by Basidiomicota and Zygomycota. Willow genotypes seem have an influence on the abundance of fungal pathogens and disease severity; among them Charlie (Salix alba x gladfelteri) and SV1 (S. eriocephala) cultivars demonstrated superior performances. Photosynthesis measurements and biomass compositions confirmed these findings. Potentially pathogenic fungi (Dothioraceae, Diaporthaceae, Glomeraceae, and Pleosporaceae) dominated in diseased or symptomatic willows, whereas potentially beneficial fungi (Coniochaetaceae, Hypoceraceae, Nectriaceae, Trichocomaceae, and Agaricaceae) prevailed in healthy plants. In-vivo and greenhouse assays showed that inoculation with potentially pathogenic fungi induced leaf necrosis, anthracnose and open cankers. However, suppression of the latter was still possible using fungal antagonists. Hence, assessment of stem/bark and leaf fungal communities with respect to willow genotypes, cuttings origin, and SRIC location, is useful for the design of an effective management strategy to increase the productivity of the SRIC-biomass systems

Bio-effectors for improved growth, nutrient acquisition and disease resistance of crops

Recent scientific approaches to sustain agricultural production in face of a growing world food demand, limited natural resources, and ecological concerns have been focusing on biological processes to support soil fertility and healthy plant growth. In this context, the use of bio-effectors, comprising living (micro-) organisms and active natural compounds, has been receiving increasing attention. In contrast to conventional fertilizers and pesticides, the effectiveness of bio-effectors is essentially not based on the substantial direct input of mineral plant nutrients, neither in inorganic nor organic forms, nor of a-priori toxic compounds. Their direct or indirect effects on plant performance are rather based on the functional implementation or activation of biological mechanisms, in particular those interfering with soil-plant-microbe interactions. The general objective of the present research work was to improve the empirical and conceptual understanding concerning the utilization of bio-effectors in agricultural practice, following the principles of plant growth stimulation, bio-fertilization and bio-control. One main aspect of investigation was the application of bio-effectors to improve the efficiency of phosphorus (P) acquisition by the plant. Promising bio-preparations based on microbial inoculants (e.g. Bacillus, Pseudomonas, Trichoderma species) as well as natural compounds (e.g. algae extracts, humic acids) were tested in screening assays, greenhouse, and field experiments to characterize their potential effectiveness under varying environmental conditions. The most significant effects on plants appeared under severely low phosphate availability, but even under controlled conditions, bio-effectors required a narrow range of conductive environmental settings to reveal their potential effectiveness. Another focus of research was the application of bio-effectors to control soil borne pathogens, which typically appear in unsound crop rotations. Emphasis was set on take-all disease in wheat induced by the fungus Gaeumannomyces graminis. While the effectiveness of oat precrops to control take-all in subsequent wheat has been attributed to microbial changes and enhanced manganese (Mn) availability in soils, the take-all fungus is known to decrease the availability of Mn by oxidation. Against this background, the effectiveness of oat precrops and alternative crop management strategies to improve the Mn status and suppress the severity of take-all in wheat was investigated under controlled and field conditions. In conclusion, none of the tested supplemental treatments, such the application of microbial bio-effectors, stabilized ammonium or manganese fertilizers, could fully substitute for the multiple effectiveness of oat precrops, which was further confirmed by the results of a field experiment. Finally, some general conclusions and perspectives are summarized. Selected bio-effectors showed a strong capacity to improve the nutrient acquisition and healthy growth of crop plants under controlled conditions, but not in field experiments. However, even under controlled conditions the strongest effects occurred when plants were exposed to abiotic or biotic stresses, such as severely limited P availability or pathogen infestation of the soil substrate, still restricting plant growth to unproductive levels. Facing this situation, there is no perspective to improve the field efficiency of promising bio-effectors applications as a stand-alone approach. The only chance to develop viable alternatives to the conventional use of fertilizers or pesticides, for an ecological intensification of agriculture that maintains high yield levels, seems to be a reasonable integration of bio-effectors into the whole crop management of sound agricultural practice.Angesichts eines weltweit wachsenden Bedarfs an Nahrungsmitteln, begrenzter natürlicher Ressourcen und ökologischer Probleme streben neuere wissenschaftliche Ansätze zur nachhaltigen Gestaltung der Landwirtschaft verstärkt die Nutzung biologischer Prozesse zur Föderung der Bodenfruchtbarkeit und eines gesunden Kulturpflanzenwachstums an. In diesem Zusammenhang hat der Einsatz von Bio-Effektoren, einschließlich lebender (Mikro-)Organismen und wirkaktiver Naturstoffe, wachsendes Interesse gefunden. Im Gegensatz zu konventionellen Düngemitteln und Pestiziden beruht die Wirksamkeit von Bio-Effektoren nicht auf dem substantiellen Direkteintrag von Pflanzennährstoffen, weder in anorganischer noch organischer Form, noch von a priori toxischen Stoffen. Die direkten oder indirekten Wirkungen von Bio-Effektoren auf die Pflanze basieren vielmehr auf der Implementierung oder Aktivierung von biologischen Wirkungsmechanismen, insbesondere solcher die mit den Interaktionen von Boden, Pflanze und Mikroorganismen interferieren. Ziel der vorliegenden Arbeit war es, das Verständnis zur Nutzung von Bio-Effektoren in der landwirtschaftlichen Praxis anhand der prinzipiellen Wirkungskategorien von direkter Stimulans des Pflanzenwachstums, biologischer Pflanzenernährung (bio-fertilization) und biologischem Pflanzenschutz (bio-control) zu erweitern. Ein Hauptaspekt galt der Anwendung von Bio-Effektoren um die Aneignungseffizienz von Phosphor (P) durch die Pflanze zu steigern. Aussichtsreiche Präparate, basierend auf mikrobiellen Inokula (z.B. Bacillus, Pseudomonas, Trichoderma Spezies) als auch Naturstoffen (z.B. Algenextrakte, Huminsäuren), wurden in Screeningassays, Gewächshaus- und Feldversuchen getestet um ihr Wirkungspotential unter variablen Umweltbedingungen zu charakterisieren. Die stärksten Effekte traten unter Bedingungen mit sehr geringer Phosphatverfügbarkeit auf, jedoch selbst unter kontrollierten Bedingungen war der Einfluss förderlicher und teilweise eng bestimmter Umweltfaktoren notwendig um die Wirksamkeit von Bio-Effektoren zu zeigen. Ein weiteres Thema war der Einsatz von Bio-Effektoren zur Bekämpfung bodenbürtiger Krankheitserreger, welche durch unausgewogene Fruchtfolgen gefördert werden. Die Untersuchungen befassten sich insbesondere mit der Schwarzbeinigkeit des Weizens, einer bedeutenden Wurzelkrankheit hervorgerufen durch den Pilz Gaeumannomyces graminis. Eine effektive Vorfrucht zur Bekämpfung der Schwarzbeinigkeit ist Hafer, was in Zusammenhang mit mikrobiellen Veränderungen im Boden und einer erhöhten Verfügbarkeit von Mangan (Mn) für die Folgefrucht Weizen gestellt wurde. Vor diesem Hintergrund wurde die Wirksamkeit von Hafer als Vorfrucht im Vergleich mit alternativen Maßnahmen des pflanzenbaulichen Managements zur Steigerung der Mn-Versorgung und Bekämpfung der Schwarzbeinigkeit in Weizen untersucht. Fazit war, daß keine der getesten Alternativmaßnahmen, wie die Anwendung mikrobieller Bio-Effektoren, stabilisierten Ammonium- oder Mangandüngers, die vielseitige Vorfruchtwirkung von Hafer vollständig substituieren konnte, was auch durch die Ergebnisse eines Feldversuches bestätigt wurde. Abschließend folgen generelle Schlussfolgerungen aus der vorliegenden Arbeit und sich daraus ergebende Perspektiven zur Nutzung von Bio-Effektoren. Ausgewählte Bio-Effektoren zeigten unter kontrollierten Bedingungen ein hohes Wirkungspotential zur Förderung der Nährstoffaneignung und des gesunden Wachstums von Kulturpflanzen, nicht jedoch in Feldversuchen. Zudem waren die stärksten Effekte dann zu beobachten, wenn die Pflanzen abiotischen oder biotischen Stresssituationen, wie stark limitierter P-Verfügbarkeit oder einem pathogenbelasteten Bodensubstrat, ausgesetzt waren, welche das Pflanzenwachstum auch weiterhin auf ein unproduktives Maß beschränkten. Diese Ergebnisse eröffnen keine Perspektive den praktischen Nutzen von Bio-Effektoren durch Einzelmaßnahmen zu steigern. Vielmehr schein der einzig erfolgversprechende Ansatz leistungsfähige Alternativen zum konventionellen Einsatz von Düngemitteln und Pestiziden für eine ökologische Intensivierung der Agrarproduktion auf hohem Ertragsniveau zu entwickeln, eine sinnvolle Integration von Bio-Effektoren in das gesamte pflanzenbauliche Management einer fachgerechten Landwirtschaft zu sein

Effectiveness of Endophytic Bacteria from Local Tomato Plants Against Wilt Disease Caused by Fusarium oxysporum

Fusarium wilt is a plant disease caused by Fusarium oxysporum that generates significant economic loss to crops. A method to sustainably control F. oxysporum is utilizing biological agents, such as endophytic bacteria. Therefore, this study aimed to isolate endophytic bacteria from tomato plant tissue, which could inhibit the pathogen of wilt disease (F. oxysporum). Endophytic bacteria were isolated from local tomato plants in Muna Regency, Indonesia. Morphological characteristics such as size, shape, color and height of bacterial colonies were then determined by Gram staining using potassium hydroxide (KOH). Endophytic bacterial isolates were evaluated for their ability to inhibit F. oxysporum through inhibition and hydrogen cyanide (HCN) production tests. Subsequently, analysis of variance was used to determine whether endophytic bacteria inhibited F. oxysporum growth, and if there was a significant effect, Duncan's test was conducted at 95% significance. HCN production was observed through qualitative methods. The results showed that four endophytic bacteria isolates, namely LBR I A03, SWR II B04, SDM II B05 and SWR I A02 inhibited the growth of F. oxysporum by more than 50%. It also revealed that four endophytic bacterial isolates were strong HCN producers and two were weak producers. Therefore, isolates showing antifungal activity in this study can be used as biopesticide agents to induce plant resistance to F. oxysporum

Occurrence and Functions of Endophytic Fungi in Crop Species

In the past few decades, awareness of the basic role that endophytic fungi play in shaping the fitness of both wild and crop plants has increased significantly. The number of papers on the subject is so large that it is becoming difficult to have a complete overview of the state-of-the-art with reference to specific crops. In the absence of readily available documents providing circumstantial information on the endophytic assemblage of plants, the isolation of a certain fungal species may appear to be occasional or trivial; hence, many important findings are at risk of going unnoticed. This Special Issue aims to present a collection of papers dealing with the occurrence and functions of endophytic fungi in crop species. It may represent a useful tool for stakeholders in this particular research field, with a view to stimulating a more thorough consideration of the opportunities deriving from their discoveries

Application of Plant Growth Promoting Microorganism and Plant Growth Regulators in Agricultural Production and Research

Plant growth-promoting microorganisms (PGPM) are groups of rhizosphere microorganisms capable of colonizing the root environment. Some of the microbes that inhabit this zone are bacteria and fungi that are capable of efficiently colonizing roots and rhizosphere soil. These microorganisms can be used as biofertilizers for improving agricultural production even under stressful environmental conditions. In contrast to PGPM, plant growth regulators (PGR) are chemical compounds that significantly affect the growth and differentiation of plant cells and tissues. They function as chemical messengers for intercellular communication and play a vital role in plant signaling networks as they are involved in the plant developmental process and a wide range of biotic and abiotic stress responses. The application of PGPM and plant growth regulators/hormones or the synthesis of PGR and signal transduction, perception, and cross-talk creates a complex network that plays an essential role in the regulation of plant physiological processes. A better understanding of the mechanism of action of PGPM and PGR and their roles in plant growth and development, interaction and independence in their action, and hormonal crosstalk under stresses is essential for agricultural production and research. Therefore, this book has contributions in the form of research and review papers from eminent scientists worldwide and discusses the role of PGPM and PGR in agriculture production and research, their potentials as biocontrol agents, their effects on physicochemical properties of soil, innovation for sustainable agriculture, their role in seed transplanting, and their role in mitigating biotic and abiotic stresses

Characterisation of fusarium pathogens in the UK

The primary aim of this project was to identify and characterise Fusarium species associated with the basal rot of Allium species and internal fruit rot of sweet peppers in the UK. The secondary objective was to develop quick molecular markers to identify Fusarium oxysporum f. sp. cepae (FOC) causing onion basal rot. Isolates representing diverse Fusarium species taken from onions, garlic, shallot and leeks obtained from different production and processing sites in the UK were collected. F. proliferatum was found for the first time to be a causal agent of onion basal rot in the UK, but F. oxysporum was by far the most common species and F. oxysporum isolates belonged to at least two different genotypes based on a sequence comparison of several “housekeeping” genes, and overall, appeared to be polyphyletic. None of the housekeeping genes studied correlate with pathogenicity. Secreted in xylem (SIX) genes offer more promise for the specific identification of F. oxysporum formae speciales (Lievens et al., 2009a) and a homologue of the SIX7 gene was found only in a few FOC isolates suggesting that SIX7 is not absolutely necessary for pathogenicity. Whole genome sequencing of a FOC isolate was carried out in order to understand pathogenicity and identify novel effector genes. This work revealed the presence of further homologues of published SIX genes, namely SIX3, SIX5 and SIX9. The presence of SIX3 and SIX5 has only been reported from F. oxysporum f. sp. lycopersici previously. Additionally, screening of eleven new candidate effector genes suggested that FOC isolates have different gene sets which correspond to the continuous variation of aggressiveness found within the FOC population. Fusarium lactis, F. proliferatum and F. solani were identified in association with internal fruit rot of sweet pepper obtained from three different production sites in the UK