BACKGROUND: Sweet potato whitefly (Bemisia tabaci) is one of the most destructive pests to an extensive range of crops and vegetables. Pesticide‐dependent management programs have led to severe health problems, including pesticide poisoning and cancer in human beings, as well as pesticide resistance in insect pests. Entomopathogenic fungi (EPF) are considered safe and highly effective against many pests. Therefore, identifying the pathogenicity and virulence of EPFs against Bemisia tabaci is a valuable addition to the management of their infestations. In this study, we investigated the efficacy of conidia suspensions of Aschersonia aleyrodis, Isaria fumosorosea, Beauveria bassiana, and Akanthomyces muscarius (= Lecanicillium muscarium) against nymphal stages of Bemisia tabaci in cucumber seedlings under both optimal and suboptimal conditions.RESULTS: All of the EPFs demonstrated significant ovicidal effects, with the highest cumulative mortalities observed in Aschersonia aleyrodis (96.46%) and I. fumosorosea‐treated (94.60%) seedlings against host eggs and crawlers. Similarly, in the L4‐instars experiment, Aschersonia aleyrodis and I. fumosorosea were the most efficient, resulting in cumulative mortalities of 94.82% and 94.75%, respectively. However, Bemisia tabaci cumulative mortalities on seedlings treated with Akanthomyces muscarius (78.36%) and Beauveria bassiana (85.90%) were also significantly different from untreated seedlings (7.10%). Under suboptimal relative humidity (RH) conditions (≤ 45% RH), Aschersonia aleyrodis exhibited greater tolerance to harsh conditions, causing a significantly higher infection rate in L1–L2 nymphs (~92%) compared to the approximately 32% infected young nymphs observed in I. fumosorosea‐treated seedlings.CONCLUSION: All the selected EPF were more effective against the young nymphal instars. Our results also highlight the efficacy of Aschersonia aleyrodis under suboptimal conditions. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Daunorubicin (DNR) is an anthracycline antibiotic originating from soil-dwelling actinobacteria extensively used to treat malignant tumors. Over the decades, extensive attempts were made to enhance the production of anthracyclines by introducing genetic modifications and mutations in combination with media optimization, but the target production levels remain comparatively low. Developing an appropriate culture medium to maximize the yield of DNR and preventing autotoxicity for the producing organism remains a challenge. Our prospective review sheds light on a method involving perturbation that enhances the precursors to regulate the type II PKS pathway, enhancing cells’ capacity to increase secondary metabolite production. The suggested method also entails the preparation of culture media for the cultivation of Streptomyces sp. and enhanced yield of DNR, as well as making it inactive with iron or its reduced forms following efflux from the producer. The iron or iron–DNR complex is encapsulated by oleic acid or lipid micelle layers in the culture media, finally resulting in the generated inactive DNR and the DNR–iron–oil complex. This idea has the potential to protect the producer organism from autotoxicity and prevent the inhibition of metabolite production. The approach of substituting sugar with oil in culture media has a dual role wherein it promotes Streptomyces growth by utilizing lipids as an energy source and encapsulating the generated DNR–iron complex in the medium. In this review, we discussed aspects like anthracycline producers, biosynthesis pathways, and gene regulation; side effects of DNR; mechanisms for autotoxicity evasion; and culture media components for the enhancement of DNR production in Streptomyces sp. We anticipate that our work will help researchers working with secondary metabolites production and decipher a methodology that would enhance DNR yield and facilitate the extraction of the resulting DNR by lowering costs in large-scale fermentation.

Daunomycin is a chemotherapeutic agent widely used for the treatment of leukemia, but its toxicity toward healthy dividing cells limits its clinical use and its production by fermentation. Herein, we describe the development of a specialized cultivation medium for daunomycin production, including a shift to oil rather than sugar as the primary carbon source. This achieved an almost threefold increase in daunomycin yields, reaching 5.5–6.0 g/L. Daunomycin produced in the oil-based medium was predominantly found in the solid sediment, whereas that produced in the sugar-based medium was mostly soluble. The oil-based medium thus induces an autonomous daunomycin-resistance mechanism involving biogenic nanoparticle formation. The characterization of the nanoparticles confirmed the incorporation of iron and daunomycin, indicating that this approach has the potential to mitigate cytotoxicity while improving yields. The presence of proteins associated with iron homeostasis and oxidative stress responses revealed the ability of the production strain to adapt to high iron concentrations. Our findings provide insight into the mechanisms of biogenic nanoparticle formation and the optimization of cultivation processes. Further investigation will help to refine microbial production systems for daunomycin and also broaden the application of similar strategies for the synthesis of other therapeutically important compounds.

Legumes are indispensable crops in sustainable agricultural systems because of their capability for biological nitrogen fixation owing to symbiosis with rhizobia and soil fertility restoration. Fungal pathogens from the genera Fusarium cause rotting and wilting and produce mycotoxins in plant tissues. The use of fungicides in sustainable agricultural systems is limited; therefore, the application of biological agents with antifungal activity against Fusarium spp. is desirable. Lactic acid bacteria (LAB) are promising control agents that produce a wide spectrum of functional metabolites. Lactiplantibacillus plantarum and other lactobacilli are the most intensively studied genera of LAB in relation to antifungal activity against Fusarium spp. However, LAB strains belonging to the lactobacilli and lactococci genera have not yet been isolated and characterised from legumes. Therefore, we aimed to obtain wild strains of LAB from legumes, screen them for functional characteristics with respect to their antifungal activity, and compare their antifungal activity against isolates of Fusarium spp. from legumes. Consequently, 31 LAB isolates belonging to 10 species were obtained and identified from legumes. Their functional properties, including genetics and proteomics, short-chain organic acid production, and antifungal activity against five Fusarium spp., of Lactiplantibacillus plantarum, Lacticaseibacillus paracasei, and Lactiplantibacillus pentosus isolates, were studied. Cell-free supernatants of L. plantarum and L. pentosus showed significant suppression of mycelial growth and conidial germination.

The adoption of biological control strategies plays a crucial role in ensuring the sustainability of organic agricultural practices. A field experiment was conducted in 2023 and 2024 to evaluate the impact of biological treatments using lactic acid bacteria (LAB) Lactiplantibacillus plantarum and mycoparasitic fungus (MPF) Trichoderma virens applied through seed treatment and foliar application separately and in combination on agronomic characteristics and pea yield in organic cultivation. Seed treatment with LAB and MPF resulted in a notable improvement in shoot length and root dry weight, while an increase in root nodule number was observed exclusively with LAB. The combined application of MPF as a seed treatment and LAB as a foliar application at the flowering stage significantly enhanced pod weight per plant, seed number per pod and per plant, and seed weight compared to treatments with LAB applied as either a foliar or seed treatment separately, as well as the untreated control. However, the yield responses to individual and combined treatments under field conditions demonstrated variability and inconsistency. Protein content ranged from 21.24% to 21.61%, and no significant differences observed between treatments. This is the first field report directly comparing the effectiveness of treatments on organic pea production. The findings offer promising avenues for assessing the long-term impacts of these treatments on the sustainable intensification of pea cultivation.