Selection of Endophytic Beauveria bassiana as a Dual Biocontrol Agent of Tomato Pathogens and Pests

Di Lelio I., Coppola M., Comite E., Molisso D., Lorito M., Woo S.L., Pennacchio F., Rao R., Digilio M.C.

Species of the ecological opportunistic, avirulent fungus, Trichoderma are widely used in agriculture for their ability to protect crops from the attack of pathogenic fungi and for plant growth promotion activity. Recently, it has been shown that they may also have complementary properties that enhance plant defense barriers against insects. However, the use of these fungi is somewhat undermined by their variable level of biocontrol activity, which is influenced by environmental conditions. Understanding the source of this variability is essential for its profitable and wide use in plant protection. Here, we focus on the impact of temperature on Trichoderma afroharzianum T22, Trichoderma atroviride P1, and the defense response induced in tomato by insects. The in vitro development of these two strains was differentially influenced by temperature, and the observed pattern was consistent with temperature-dependent levels of resistance induced by them in tomato plants against the aphid, Macrosiphum euphorbiae, and the noctuid moth, Spodoptera littoralis. Tomato plants treated with T. afroharzianum T22 exhibited enhanced resistance toward both insect pests at 25°C, while T. atroviride P1 proved to be more effective at 20°C. The comparison of plant transcriptomic profiles generated by the two Trichoderma species allowed the identification of specific defense genes involved in the observed response, and a selected group was used to assess, by real-time quantitative reverse transcription PCR (qRT-PCR), the differential gene expression in Trichoderma-treated tomato plants subjected to the two temperature regimens that significantly affected fungal biological performance. These results will help pave the way toward a rational selection of the most suitable Trichoderma isolates for field applications, in order to best face the challenges imposed by local environmental conditions and by extreme climatic shifts due to global warming.

Sinno M., Ranesi M., Gioia L., d’Errico G., Woo S.L.

Endophytic fungi (EF) are increasingly gaining attention due to the numerous benefits many species can offer to the plant host, while reducing the application of chemicals in agriculture, thus providing advantages to human health and the environment. The growing demand for safer agrifood products and the challenge of increasing food production with a lower use of pesticides and fertilizers stimulates investigations on the use and understanding of EF. Other than direct consequences on the plant damaging agents, these microorganisms can also deliver bioactive metabolites with antimicrobial, insecticidal, or plant biostimulant activities. In tomato, EF are artificially introduced as biological control agents or naturally acquired from the surrounding environment. To date, the applications of EF to tomato has been generally limited to a restricted group of beneficial fungi. In this work, considerations are made to the effects and methods of introduction and detection of EF on tomato plants, consolidating in a review the main findings that regard pest and pathogen control, and improvement of plant performance. Moreover, a survey was undertaken of the naturally occurring constitutive endophytes present in this horticultural crop, with the aim to evaluate the potential role in the selection of new beneficial EF useful for tomato crop improvement.

Fraser E.D.

The purpose of this paper is to provide a high-level overview of arguments related to “feeding the future.” Briefly, this paper opens by exploring the very serious challenge of feeding the world's global population in a way that is sustainable, equitable, nutritious and economically efficient. Part two of this paper presents some of the technological innovations that are proposed as partial solutions to the global food security challenge. The final part of this paper reflects on three specific sociopolitical considerations that must be considered in order to ensure that technological innovation addresses the global food security challenge.

Lombardi N., Salzano A.M., Troise A.D., Scaloni A., Vitaglione P., Vinale F., Marra R., Caira S., Lorito M., d’Errico G., Lanzuise S., Woo S.L.

Fungi of the genus Trichoderma produce secondary metabolites having several biological activities that affect plant metabolism. We examined the effect of three Trichoderma bioactive metabolites (BAMs), namely, 6-pentyl-α-pyrone (6PP), harzianic acid (HA), and hydrophobin 1 (HYTLO1), on yield, fruit quality, and protein representation of strawberry plants. In particular, 6PP and HA increased the plant yield and number of fruits, when compared to control, while HYTLO1 promoted the growth of the roots and increased the total soluble solids content up to 19% and the accumulation of ascorbic acid and cyanidin 3-O-glucoside in red ripened fruits. Proteomic analysis showed that BAMs influenced the representation of proteins associated with the protein metabolism, response to stress/external stimuli, vesicle trafficking, carbon/energy, and secondary metabolism. Results suggest that the application of Trichoderma BAMs affects strawberry plant productivity and fruit quality and integrate previous observations on deregulated molecular processes in roots and leaves of Trichoderma-treated plants with original data on fruits.

Wei Q., Li Y., Xu C., Wu Y., Zhang Y., Liu H.

Beauveria bassiana, an entomopathogenic fungus, can exist asymptomatically as an endophyte in many plants. This study aimed to determine the efficiency of B. bassiana colonization of tomato plants using different inoculation methods, and how colonization of the host plant affects the key pest of tomato, the whitefly Bemisia tabaci. To confirm fungal colonization efficiency, nested PCR technique was used to detect B. bassiana sequences in Solanum lycopersicum. Distribution of the fungus within the plant parts was determined by selective medium. Tomato growth parameters were determined with plants that had been inoculated using direct spraying or irrigation of the rhizosphere. B. tabaci performance assays were carried out in a cage, and preference to treatments was determined using Y-tube olfactometer studies. Results show that B. bassiana can effectively colonize tomato, with colonization rate using leaf spraying reaching 100% within 14 days. Fungal presence was not uniformly distributed among plant parts, but was biased towards the inoculation sites. For inoculation, conidial suspension sprayed at 1 × 108 conidia/ml resulted in the highest number of isolated colonies in leaf tissue, 8.5 ± 2.02 colonies per 2 g of fresh tissue (F4,19 = 2.779, P = 0.045), and reached the lowest with root treatment. Although only small differences were observed among the growth indicators, leaf spray inoculation resulted in a significant positive influence on plant growth (PC1 55.7% contributions scores = 2.645) in further Principal component analysis. As for the feeding selectivity, B. tabaci preferred uninoculated plants. In Y-tube olfactometer assay, 80.5% of adults selected uninoculated plants. These findings add to the understanding of the interactions between B. bassiana and plants and indicate the potential of expanding the use of entomopathogenic fungi for crop protection.

Barra-Bucarei L., France Iglesias A., Gerding González M., Silva Aguayo G., Carrasco-Fernández J., Castro J.F., Ortiz Campos J.

Botrytis cinerea causes substantial losses in tomato and chili pepper crops worldwide. Endophytes have shown the potential for the biological control of diseases. The colonization ability of native endophyte strains of Beauveria bassiana and their antifungal effect against B. cinerea were evaluated in Solanaceae crops. Root drenching with B. bassiana was applied, and endophytic colonization capacity in roots, stems, and leaves was determined. The antagonistic activity was evaluated using in vitro dual culture and also plants by drenching the endophyte on the root and by pathogen inoculation in the leaves. Ten native strains were endophytes of tomato, and eight were endophytes of chili pepper. All strains showed significant in vitro antagonism against B. cinerea (30–36%). A high antifungal effect was observed, and strains RGM547 and RGM644 showed the lowest percentage of the surface affected by the pathogen. Native strains of B. bassiana colonized tomato and chili pepper tissues and provided important levels of antagonism against B. cinerea.

Rondot Y., Reineke A.

Mahmood Z., Steenberg T., Mahmood K., Labouriau R., Kristensen M.

• Endophytic establishment of Beauveria bassiana was 100% in maize plants. • The survival of Sitobion avenae on inoculated maize plants was reduced up to 49%. • There was no sign of mycosis in dead aphids. • The numbers of S. avenae nymphs were reduced on treated and untreated leaves of inoculated plants. • Negative effects on S. avenae appear to be systemic. The entomopathogenic fungus Beauveria bassiana is able to colonize and establish a symbiotic relationship with plants as an endophyte, naturally as well as through artificial inoculation. This study aims at implementing a reliable and efficient method to establish endophytic B. bassiana in maize plants. The level of the endophytic establishment was evaluated and the survival and fecundity of the English grain aphid ( Sitobion avenae ) was investigated. Eight-days-old maize plants were sprayed with a fungal spore suspension, while control plants were treated only with a Tween solution. Two weeks after inoculation, seven clip cages per plant, each containing an adult aphid, were attached to different leaves and left for seven days. All inoculated plants contained endophytic B. bassiana as confirmed by plating surface disinfected leaf pieces on selective plates. None of the control plants showed growth of B. bassiana . The highest colonization levels were 61% in older inoculated leaves and 19% in younger non-inoculated leaves. The survival of S. avenae on inoculated plants was reduced up to 49% as compared to control plants. Dead aphids did not show any signs of mycosis. The number of nymphs produced by a single aphid was reduced up to 70% and 74% on inoculated and non-inoculated leaves, respectively. Presence of endophytic B. bassiana in non-inoculated younger leaves implies the movement of the endophyte inside plants. The negative effect on aphid fecundity appears to be systemic as implied by the almost equal reduction of mean numbers of nymphs produced on older and younger leaves on the inoculated plants, irrespective of the level of colonization by endophytic B. bassiana .

Segaran G., Sathiavelu M.

Endophytes protect the host plant for their entire life cycle and they have the ability to act as a biocontrol agent. Organisms protect the host plant through antibiosis, parasitism and competition mechanism in the biocontrol process. The improper and excessive use of agrochemicals makes the phytopathogens insensitive and leads to the development of resistant fungal pathogens. Chemical fungicides are expensive and have many negative impacts on the environment. The use of endophyte as the biocontrol agent is effective in controlling the plant disease and to achieve sustainable agriculture. Endophytes have antagonistic activity against disease-causing phytopathogens and also capable to produce antimicrobial, insecticidal, antioxidant, anti-tumor and anti-viral metabolites. Perfumoid, phomoenamide, joxysporidinone, alantrypinene, alantryleunone, (−)-4,6′-anhydrooxysporidinone and (−)-6-deoxyoxysporidinone are the few alkaloid compounds of endophytic fungi. Nidurufin, sterigmatocystin, averantin, 11a-methoxycurvularin 4, 11b-methoxycurvularin, tenellone H, phomopene and 1-chloro-2,4-dihydroxy-5-methoxy-7-methylanthraquinone are the endophytic fungal compounds reported with cytotoxic activity in the year between 2008-2019. The present review concentrates on the antagonistic activity of endophytes towards phytopathogens and their bioactive secondary metabolites with pharmacological properties.

Coppola M., Diretto G., Digilio M.C., Woo S.L., Giuliano G., Molisso D., Pennacchio F., Lorito M., Rao R.

Beneficial fungi in the genus Trichoderma are among the most widespread biocontrol agents of plant pathogens. Their role in triggering plant defences against pathogens has been intensely investigated, while, in contrast, very limited information is available on induced barriers active against insects. The growing experimental evidence on this latter topic looks promising, and paves the way towards the development of Trichoderma strains and/or consortia active against multiple targets. However, the predictability and reproducibility of the effects that these beneficial fungi is still somewhat limited by the lack of an in-depth understanding of the molecular mechanisms underlying the specificity of their interaction with different crop varieties, and on how the environmental factors modulate this interaction. To fill this research gap, here we studied the transcriptome changes in tomato plants (cultivar “Dwarf San Marzano”) induced by Trichoderma harzianum (strain T22) colonization and subsequent infestation by the aphid Macrosiphum euphorbiae. A wide transcriptome reprogramming, related to metabolic processes, regulation of gene expression and defence responses, was induced both by separate experimental treatments, which showed a synergistic interaction when concurrently applied. The most evident expression changes of defence genes were associated with the multitrophic interaction Trichoderma-tomato-aphid. Early and late genes involved in direct defence against insects were induced (i.e. peroxidase, GST, kinases and polyphenol oxidase, miraculin, chitinase), along with indirect defence genes, such as sesquiterpene synthase and geranylgeranyl phosphate synthase. Targeted and untargeted semi-polar metabolome analysis revealed a wide metabolome alteration showing an increased accumulation of isoprenoids in Trichoderma treated plants. These data nicely fit with the higher mortality of aphids when feeding on Trichoderma treated plants, herein reported, and with the previously observed attractiveness of these latter towards the aphid parasitoid Aphidius ervi. Moreover, Trichoderma treated plants showed the over-expression of transcripts coding for several families of defence-related transcription factors (bZIP, MYB, NAC, AP2-ERF, WRKY), suggesting that the fungus contributes to the priming of plant responses against pest insects. Collectively, our data indicate that Trichoderma treatment of tomato plants induces transcriptomic and metabolomic changes, which underpin both direct and indirect defence responses.

Mantzoukas S., Lagogiannis I.

Aphids are among the most harmful crop pests, damaging plants by sucking sap or by transmitting pathogenic viruses. Plant infestation by aphids depends on their population growth. Entomopathogenic fungi are essential participants of terrestrial and aquatic ecosystems, regulating arthropod communities. Many fungal species with a symbiotic–endophytic relation with plants are pathogenic, producing insecticides or insect repellents. The present study investigated the effects of the fungal entomopathogens Beauveria bassiana, Metarhizium anisopliae and Isaria fumosorosea, following their endophytic colonization of the sweet pepper Capsicum annum, on the development of the green peach aphid Myzus persicae. After 21 days, B. bassiana produced 100% aphid mortality, M. anisopliae 90% and I. fumosorosea 83.3%. There were also significant differences in terms of the effect on aphid population in planta and on the survival time of young adults in planta. External mycelium appeared within 96 h after placing aphid cadavers on damp filter paper. PCR confirmed that the mycelium was of B. bassiana, M. anisopliae and I. fumosorosea. DNA sequences collected from this work were matched with existing sequences data in GenBank, using the Basic Local Alignment Search Tool. Our results showed that none of the three fungal isolates had an effect in promoting or suppressing the growth of C. annum.

Afandhi A., Widjayanti T., Emi A.A., Tarno H., Afiyanti M., Handoko R.N.

Common bean (Phaseolus vulgaris L.) is a source of antioxidant-containing vegetable protein that is beneficial to human health. The intense cultivation of common bean may result in environmental degradation. Thus, environmentally friendly cultivation methods that use an endophyte to improve productivity are needed. An entomopathogenic fungus, Beauveria bassiana, can serve as an endophyte that stimulates the growth of Gossypium. Therefore, we isolated and identified B. bassiana and also examined its function as a beneficial endophyte that promotes the growth of common bean. An entomopathogenic fungus, B. bassiana, was collected and identified based on macroscopic and microscopic characteristics that were observed during morphological examination. B. bassiana was propagated and inoculated into common bean via seed soaking, soil wetting, and leaf spraying. The soil-wetting and leaf-spraying methods used to inoculate B. bassiana effectively enhanced the growth of common bean, which was observed at day 10 post-inoculation. However, no significant growth enhancement of common bean was observed when the seed-soaking inoculation method was used. These results suggest a positive correlation between the B. bassiana inoculation method and growth enhancement of common bean. This study showed the endophytic potency of the fungus that may be used in the development of environmentally friendly cultivation methods of common bean.

Marra R., Lombardi N., d’Errico G., Troisi J., Scala G., Vinale F., Woo S.L., Bonanomi G., Lorito M.

Trichoderma fungi are effectively marketed worldwide as biocontrol agents and plant biostimulants on numerous crops due to their demonstrated effects in direct antagonism against fungal pathogens and plant growth promotion. Here, we examined the effects of single and combined applications of Trichoderma strains and their bioactive metabolites (BAMs) harzianic acid (HA), 6-pentyl-α-pyrone (6PP), and hydrophobin1 (HYTLO1) on the growth, yield, and nutrient uptake of soybean plants. Significant promotion of plant growth (up to 39%), as well as an increase in mineral content, was achieved with BAMs, used alone or combined with T. harzianum. Interestingly, the treatments also increased the level of fatty acids (oleic, linolenic, 11-eicosenoic, and stearic). This work demonstrates the usefulness of natural compound and microbe combinations to enhance oilseed productivity, and reports for the first time the ability of Trichoderma and/or its BAMs to increase the lipid content in harvested seeds.

Morton G.D.

Can cash assistance have an influence on gender relations inside a household? What are the processes through which this influence occurs? The present article investigates the everyday uses of money that women receive from two gender-targeted social programs in rural Brazil. Bolsa Familia is a conditional cash transfer that disburses money to women every month. The Maternity Wage is a program that gives a sizeable lump sum to women when they become pregnant. Drawing from two years of ethnographic research in two villages in Northeastern Brazil, I show how these different payment schedules can lead to different patterns of investment in assets. I find that women typically spend monthly cash assistance on items, like clothing and furniture, that correspond to local stereotypes about feminine property. By contrast, lump sums are used by women to purchase income-generating assets, like cows and fields, that would normally be held by men. Monthly money reinforces gendered stereotypes about assets, while lump-sum money challenges those stereotypes. Lump sums thereby enable women to become the owners of wealth that generates a flow of income over time. I identify two key qualities that underlie this change: a payment’s large size and its unpredictability. These qualities affect the mental accounting that beneficiaries use to understand their money and the institutions through which they save it. By outlining such processes, the article brings the literature on conditional cash transfers into dialogue with studies on the gender asset gap. Lump sums can help to re-gender a household’s assets. This finding suggests that cash assistance policy, particularly in the case of conditional cash transfers, might be able to have an effect on gender equity by making use of targeted lump sums.

Woo S.L., Pepe O.

Matanog A.K., Solpot T.C., Bretaña B.L., Tanabe M.E., Cabasan M.T.

Liu M., Xiang D., Hokkanen H.M., Niu T., Zhang J., Yang J., Wei Q., Chen H., Liu H., Li Y.

Pre-stimulation of plants can change their resistance mechanisms, thereby enhancing their defense responses. Beauveria bassiana, a broad-spectrum entomogenous fungi, can also induce plant defenses, but it received little attention. Here, we show that B. bassiana can act as a stimulus to prime tomato defense responses, improving resistance in the plant to herbivore stress. The results illustrated that four defense genes (PIN2, PR2, PAL, and MPK3) were upregulated in all B. bassiana treatments, especially the phenylalanine deaminase (PAL) gene, which was highly expressed in tomato plants after B. bassiana inoculation. Feeding through Bemisia tabaci resulted in a weak upregulation of defense genes. However, in combined fungal inoculation and B. tabaci feeding, a total of nine defense genes were upregulated, among which five genes—PAL, PPO, PIN2, PR2, and PR1—were closely related to the phenol synthesis. The results of tomato plant metabolism showed that B. bassiana mainly activates tomato phenylpropane metabolic pathways, with this modulation being influenced by jasmonate. Further explorations revealed a significant enhancement in the antioxidant capacity of the plants, as evidenced by the determination of their antioxidant compounds and the coloration of leaf phenolic substances. Thus, entomopathogenic fungi can act as an exogenous substance to activate the defense responses of tomatoes without damaging the plant, indicating a good potential for developing applications using B. bassiana to promote resistance in tomatoes for pest management.

Sui L., Lu Y., Cheng K., Tian Y., Liu Z., Xie Z., Zhang Z., Li Q.

Zhang H., Mao A., Liu Y., Fu Y., Cheng J., Jin D., Fan Y.

AbstractBACKGROUNDThe entomopathogenic fungus Beauveria bassiana has been widely used for pest biocontrol with conidia serving as the main active agents. Conidial yield and quality are two important characteristics in fungal conidia development, however, the regulatory mechanisms that orchestrate conidial formation and development are not well understood.RESULTSIn this study, we identified a Zn2Cys6 transcription factor BbCDR1 that inhibits conidial production while promoting conidial maturation. Compared with the wild type, the ΔBbCDR1 mutant exhibited a 1.88‐fold increase in conidial yield but a reduction in conidial quality, including decreased cell wall integrity and trehalose synthesis. The deletion of BbCDR1 also led to reduced conidial germination rates under oxidative, osmotic, conidial wall disruption and UV stresses. Interestingly, ΔBbCDR1 exhibited an increase of fungal virulence with a 12.5% decrease in LT50 compared to the wild type.CONCLUSIONSFurther analysis revealed that BbCDR1 represses the expression of BbbrlA and activates BbwetA, two components of the central developmental pathway (CDP) that regulate conidial initiation and maturation, respectively. These findings suggest that BbCDR1 plays a crucial role in conidial development and a new target gene for the genetic engineering of highly active fungal insecticides. © 2025 Society of Chemical Industry.

Kamal N., Saharan B.S.

The earth’s surface constitutes a layer of soil around it which is termed as pedosphere. Soil holds millions of microbes that are involved in improving soil fertility. The increasing use of chemical fertilizers has become a major factor which is deteriorating soil microflora. It has resulted in decreased soil fertility. Soil organisms are involved in a number of processes like cycling of soil nutrients and providing them to plants. They are also involved in volatilization that may lead to nutrient loss. Microorganisms have an important role in carbon, nitrogen, and sulfur transformations, as well as organic matter degradation. They have an impact on the global nutrient and carbon cycle. The soil microflora is also involved in modulating the various physico-chemical properties of soil like pH, moisture, temperature etc. Soil properties and soil microorganisms are highly correlated with each other. The huge diversity of microorganisms in soil also plays a central role in regulating and supporting various ecosystem services. This review highlights the crucial role of different microbes in various nutrient cycling which is one of the major concerns to address the decreasing status of soil nutrients. It also covers various physico-chemical properties which affects soil microbial community and various ecosystem services provided by microbial activity.

Safavi S.A., Golzan S.R., Mesri-Ghahramanloo S., Michaud J.P.

Aouali S.

Since the discovery of Beauveria bassiana 200 years ago, the use of fungi to combat insect pests has been deeply explored. A few years ago, the endophytic life of some entomopathogenic fungi has been revealed, and since then, extensive research was launched to unveil more species, understand their ecology, diversity, and mechanisms of action, in order to produce efficient biopesticides and develop better control practices. Besides their use as mycopesticides, scientists also explore potential secondary metabolites that could be used in medical treatments, industry, and environmental depollution. Endophytic insect-pathogenic fungi, commonly called EIPF, are fungi establishing a mutualistic relationship with their host plants, and at the same time are capable of infecting and killing insects by antibiosis or feeding dissuasion. The ability of EIPF to live in plant tissues and to parasitize insects suggests the involvement of complex and intimate interactions that are still not fully dissected. These multikingdom encounters have coevolved millions of years ago and enabled the development of both generalist and highly specialized EIPF species, as a key strategy to colonize and establish in a variety of different environments. This chapter presents the multifaceted mechanisms involved in these intimate interactions for a successful colonization and establishment of EIPF, their potential applications in agricultural biological pest management, pharmacology, medicine, and industry, as well as the possible limitations that might arise in their use.

Vermelho A.B., Moreira J.V., Akamine I.T., Cardoso V.S., Mansoldo F.R.

Pesticide use in crops is a severe problem in some countries. Each country has its legislation for use, but they differ in the degree of tolerance for these broadly toxic products. Several synthetic pesticides can cause air, soil, and water pollution, contaminating the human food chain and other living beings. In addition, some of them can accumulate in the environment for an indeterminate amount of time. The agriculture sector must guarantee healthy food with sustainable production using environmentally friendly methods. In this context, biological biopesticides from microbes and plants are a growing green solution for this segment. Several pests attack crops worldwide, including weeds, insects, nematodes, and microorganisms such as fungi, bacteria, and viruses, causing diseases and economic losses. The use of bioproducts from microorganisms, such as microbial biopesticides (MBPs) or microorganisms alone, is a practice and is growing due to the intense research in the world. Mainly, bacteria, fungi, and baculoviruses have been used as sources of biomolecules and secondary metabolites for biopesticide use. Different methods, such as direct soil application, spraying techniques with microorganisms, endotherapy, and seed treatment, are used. Adjuvants like surfactants, protective agents, and carriers improve the system in different formulations. In addition, microorganisms are a tool for the bioremediation of pesticides in the environment. This review summarizes these topics, focusing on the biopesticides of microbial origin.

Sui L., Lu Y., Yang H., Liu Z., Wang L., Zou X., Li Q., Zhang Z.

Sunflower, a significant oleaginous crop with horticultural applications, faces challenges in yield and quality due to Sclerotinia sclerotiorum infection. As an endophyte, Beauveria bassiana demonstrated promise as a dual-purpose biocontrol agent, suppressing plant phytopathogens and inducing plant resistance against pests. While its role as an endophyte has been explored in leaf diseases, its efficacy against soil-borne diseases, especially sclerotinia disease, remains underexplored. In the present study, we evaluated the colonization ability of B. bassiana in sunflower plants through seed soaking and root irrigation methods. Additionally, we investigated its potential benefits in promoting plant growth and mitigating the negative effects of S. sclerotiorum infection. Our results showed that B. bassiana presented as an endophyte in sunflowers with both seed soaking and root irrigation treatments, leds to enhanced plant growth. Moreover, B. bassiana colonization significantly suppressed S. sclerotiorum infection in sunflower plants, even under conditions of artificial inoculation and infested soil. These findings indicate the promising ecological role of B. bassiana as a safe and effective strategy for biological control of sclerotinia disease in agroecosystems.

Adeniji A., Fadiji A.E., Li S., Guo R.

Microbial inoculants are critical tools for improving soil health and crop growth within sustainable agriculture frameworks. Despite numerous microorganisms being identified as potential candidates, their transition from laboratory efficacy to field application remains constrained by the complex and variable conditions of field environments. This review critically examines the current state of microbial inoculant research, pinpointing key challenges such as the lack of diversity in test environments and the insufficient integration of agronomic practices crucial for practical adoption. We propose the Farmer Participatory Research (FPR) model as a robust methodology to address these challenges, emphasizing the co-creation of knowledge between researchers and farmers. This approach uses the practical insights of farmers and integrates multidisciplinary scientific advances to ensure that the development of microbial inoculants is scientifically sound and practically viable in diverse agricultural settings. By adopting FPR principles, this review offers a detailed roadmap for future research, emphasizing the importance of farmer-centric approach in integrating advanced technologies like amplicon sequencing, machine learning, synthetic biology, and systems carriers in optimizing microbial inoculant performance. This paradigm shift towards a collaborative, multidisciplinary approach is poised to significantly improve field trials and establish robust agronomic management strategies for microbial inoculants, ultimately advancing microbial inoculant research.

Ranesi M., Vitale S., Staropoli A., Di Lelio I., Izzo L.G., De Luca M.G., Becchimanzi A., Pennacchio F., Lorito M., Woo S.L., Vinale F., Turrà D.

Beauveria bassiana (Bb) is a widespread entomopathogenic fungus widely used in agriculture for crop protection. Other than pest control, fungi belonging to the B. bassiana complex represent an important microbial resource in agroecosystems, considering their multiple interactions with other microorganisms as antagonists of phytopathogens, or with plants as endophytic colonizers and growth promoters. Here, we characterised field collected or commercial isolates of B. bassiana relative to the environmental factors that affect their growth. We further compared the metabolome, the entomopathogenic potential and biocontrol activity of the tested isolates respectively on the insect pest Spodoptera littoralis or against the fungal plant pathogen Fusarium oxysporum. Our analysis revealed that the B. bassiana complex is characterised by a high level of inter-isolate heterogeneity in terms of nutritional requirements, establishment of intra- or inter-kingdom interactions, and the nature of metabolites produced. Interestingly, certain B. bassiana isolates demonstrated a preference for low nutrient plant-derived media, which hints at their adaptation towards an endophytic lifestyle over a saprophytic one. In addition, there was a noticeable variation among different B. bassiana isolates in their capacity to kill S. littoralis larvae in a contact infection test, but not in an intrahaemocoelic injection experiment, suggesting a unique level of adaptability specific to the host. On the other hand, most B. bassiana isolates exhibited similar biocontrol efficacy against the soil-dwelling ascomycete F. oxysporum f. sp. lycopersici, a pathogen responsible for vascular wilt disease in tomato plants, effectively averting wilting. Overall, we show that the effectiveness of B. bassiana isolates can greatly vary, emphasising the importance of isolate selection and nutritional adaptability consideration for their use in sustainable agriculture.

Vindas-Reyes E., Chacón-Cerdas R., Rivera-Méndez W.

Trichoderma is one of the most widely used microorganisms in the biological control of plant pathogens. The techniques for its formulation are well known and are commercially distributed in both solid and liquid presentations based on formulations of its reproductive structures. Currently, agricultural systems integrate this type of fungus as an alternative for sustainable production, and even though its traditional formulation still has important limitations, it has a high potential to be combined with new technologies for the development and innovation of products that improve their effectiveness. In response to this, micro- and nanotechnology are presented as alternatives to technify bioagents, promoting greater resistance, viability, and dissemination for both biomass and metabolites through encapsulation and smart delivery techniques. Some works have been developed to achieve this, especially using ionic gelation, with good results for agriculture. In this work, some generalities of the organism are mentioned, including its most common formulations for agricultural applications, information related to encapsulation systems, and the potential for improvement of biologics represented by biomass microencapsulation.

Geremew D., Shiberu T., Leta A.

Background The tomato, Solanum lycopersicum L., is one of the most important horticultural crops that can be consumed fresh or after being processed worldwide. The tomato leaf miner (Tuta absoluta) is one of the most devastating pest to tomato plants due to its mine-feeding nature in the mesophyll tissue of the plant. Fungal entomopathogens can exist naturally in plants as an asymptote. This study aimed to detect the endophytic colonization of Beauveria bassiana and Metarhizium robertsii within tomato plants via artificial inoculation and their virulence effects on Tuta absoluta. Methods Isolates with the highest percent germination and virulence against T. absoluta were selected for endophytic evaluation within tomato plants by different artificial inoculation techniques. Results This study revealed that, isolates with the highest percent germination and virulent to Tuta absoluta had the potential to colonize tomato plants. The result showed that, the maximum mortality rate (97.5%) of Tuta absoluta larvae was achieved by Metarhizium robertsii isolate K-61 at a concentration of 1x108conidial/ml at 7 days post inoculated. However, the highest cumulative mortality (100%) was recorded by Beauveria bassiana isolate APPRC-27 at 10 days post inoculated through the direct contact method. The highest endophytic colonization was registered by isolate APPRC-27 (76.67%) at 7 days post-inoculated using the leaf spray technique, but it declined to 11.67% after 28 days of inoculated. In the case of the seedling inoculation technique, the highest endophytic colonization was obtained in the root tissues of tomatoes at 28 days of inoculated by isolate K-61. Conclusions This study revealed that the leaf spray inoculation technique was the most effective method, followed by seedling inoculation, for the deployment of Beauveria bassiana and Metarhizium robertsii endophytes in tomato plant tissues. Therefore, virulent Beauveria bassiana and Metarhizium robertsii, are promising bioagents for the control of Tuta absoluta if deployed as endophytes.

Muhorakeye M.C., Namikoye E.S., Khamis F.M., Wanjohi W., Akutse K.S.

AbstractEndophytic fungal-based biopesticides are sustainable and ecologically-friendly biocontrol agents of several pests and diseases. However, their potential in managing tomato fusarium wilt disease (FWD) remains unexploited. This study therefore evaluated effectiveness of nine fungal isolates against tomato fusarium wilt pathogen, Fusarium oxysporum f. sp. lycopersici (FOL) in vitro using dual culture and co-culture assays. The efficacy of three potent endophytes that inhibited the pathogen in vitro was assessed against FWD incidence, severity, and ability to enhance growth and yield of tomatoes in planta. The ability of endophytically-colonized tomato (Solanum lycopersicum L.) plants to systemically defend themselves upon exposure to FOL were also assessed through defence genes expression using qPCR. In vitro assays showed that endophytes inhibited and suppressed FOL mycelial growth better than entomopathogenic fungi (EPF). Endophytes Trichoderma asperellum M2RT4, Hypocrea lixii F3ST1, Trichoderma harzianum KF2R41, and Trichoderma atroviride ICIPE 710 had the highest (68.84–99.61%) suppression and FOL radial growth inhibition rates compared to EPF which exhibited lowest (27.05–40.63%) inhibition rates. Endophytes T. asperellum M2RT4, H. lixii F3ST1 and T. harzianum KF2R41 colonized all tomato plant parts. During the in planta experiment, endophytically-colonized and FOL-infected tomato plants showed significant reduction of FWD incidence and severity compared to non-inoculated plants. In addition, these endophytes contributed to improved growth promotion parameters and yield. Moreover, there was significantly higher expression of tomato defence genes in T. asperellum M2RT4 colonized than in un-inoculated tomato plants. These findings demonstrated that H. lixii F3ST1 and T. asperellum M2RT4 are effective biocontrol agents against FWD and could sustainably mitigate tomato yield losses associated with fusarium wilt.

Papantzikos V., Mantzoukas S., Eliopoulos P.A., Servis D., Bitivanos S., Patakioutas G.

In this study, the bioinsecticidal action of a commercial formulation with Beauveria bassiana was evaluated on the new sucking pest in Greece: Halyomorpha halys, of the kiwifruit. Additionally, the biostimulant potential of the same formulation was studied on kiwi growth. The application was performed in three different ways in a commercial field of kiwi crop A. deliciosa “Hayward” field in Arta, Greece: (i) trunk spray, (ii) root injection, and (iii) trunk inoculation. During the 2 years seasons of the experiment, weekly measurements of the H. halys population were determined. The insect is sucking plants nutrients; therefore, the total chlorophyll content in the leaves of the treatments was recorded weekly. In addition, the percentage of infested kiwifruits was estimated at the end of the experiment. Moreover, to study the biostimulant potential of the formulation, growth measurements on stems and leaves were performed during the experiment. Finally, at the kiwi harvest point, the fruit biomass, dimensions, and weight were obtained, and the leaves’ proline content was evaluated. The results encourage us to further study this EPF formulation as the bioinsecticidal effect was noted by the reduction in H. halys population, and biostimulant action was perceived by the higher plant biomass.