Endophytic fungi from Himalayan silver birch as potential source of plant growth enhancement and secondary metabolite production.

Mountain biodiversity is under unparalleled pressure due to climate change, necessitating in-depth research on high-altitude plant's microbial associations which are crucial for plant survival under stress conditions. Realizing that high-altitude tree line species of Himalaya are completely unexplored with respect to the microbial association, the present study aimed to elucidate plant growth promoting and secondary metabolite producing potential of culturable endophytic fungi of Himalayan silver birch (Betula utilis D. Don). ITS region sequencing revealed that the fungal isolates belong to Penicillium species, Pezicula radicicola, and Paraconiothyrium archidendri. These endophytes were psychrotolerant in nature with the potential to produce extracellular lytic activities. The endophytes showed plant growth promoting (PGP) traits like phosphorus solubilization and production of siderophore, indole acetic acid (IAA), and ACC deaminase. The fungal extracts also exhibited antagonistic potential against bacterial pathogens. Furthermore, the fungal extracts were found to be a potential source of bioactive compounds including the host-specific compound-betulin. Inoculation with fungal suspension improved seed germination and biomass of soybean and maize crops under net house conditions. In vitro PGP traits of the endophytes, supported by net house experiments, indicated that fungal association may support the growth and survival of the host in extreme cold conditions.

Different effects of selenium speciation on selenium absorption, selenium transformation and cadmium antagonism in garlic.

Currently, planting selenium-rich crops using inorganic selenium such as selenate and selenite is used to address human selenium deficiency problems. In this paper, besides the above two traditional inorganic selenium speciation, we chose a new organic selenium speciation of potassium selenocyanoacetate to investigate the different effects of selenium speciation on selenium absorption, selenium transformation and cadmium antagonism via foliar application. Plantingexperiments showed that the selenium content of garlic bulbs treated with organic selenium was 1.8-3.9 times higher than that of inorganic selenium. Additionally, the absorption and transformation efficiency of organic selenium in garlic was also the highest, reaching over 95 %. Importantly, it was noteworthy that the cadmium content in bulbs treated with organic selenium was significantly lower than the Chinese food safety standard (0.2 mg/kg). Hence, this study provides an efficient organic selenium speciation which is beneficial to meet human selenium requirements and ensure safe utilization of cadmium-contaminated soils.

Anaerobic co-fermentation of waste activated sludge with corn gluten meal enhanced phosphorus release and volatile fatty acids production: Critical role of corn gluten meal dosage on fermentation stages and microbial community traits.

The anaerobic co-fermentation of iron bound phosphorus (P) compounds (FePs)-bearing sludge with corn gluten meal (CGM) and the underlying mechanisms associated with P release and volatile fatty acids (VFAs) production were investigated. The optimal CGM dosage for P release was 0.6 g chemical oxygen demand (COD)/g total suspended solid (TSS), which resulted in an increase in efficiency from 7 % (control sample) to 39 %. However, the optimal CGM dosage for VFAs production was 0.4 g COD/g TSS, and the yield increased from 37.4 (control sample) to 331.7 mg COD/g volatile suspended solid. The addition of CGM enhanced hydrolysis and acidogenesis by supplying abundant organic substrates to promote the growth of hydrolytic and acidogenic bacteria. A higher VFAs/ammonium-nitrogen ratio resulted in a lower pH, which promoted greater FePs dissolution and P release from the sludge. This study provides novel insights into the effects of CGM on P release and VFAs production.

150 Years of Coevolution Research: Evolution and Ecology of Yucca Moths (Prodoxidae) and Their Hosts.

Yucca moths (Tegeticula and Parategeticula) are specialized pollinators of yucca plants, possessing unique, tentacle-like mouthparts used to actively collect pollen and deposit it onto the flowers of their hosts. The moths' larvae feed on the developing seeds and fruit tissue. First described in 1873, the yucca-yucca moth pollination system is now considered the archetypical example of a coevolved intimate mutualism. Research conducted over the past three decades has transformed our understanding of yucca moth diversity and host plant interactions. We summarize the current understanding of the diversity, ecology, and evolution of this group, review evidence for coevolution of the insects and their hosts, and describe how the nature of the interaction varies across evolutionary time and ecological contexts. Finally, we identify unresolved questions and areas for future research.

Magnesium and manganese induced changes on chemical, nutritional, antioxidant and antimicrobial properties of the pansy and Viola edible flowers.

Pansy and viola edible flowers were grown hydroponically with different levels of Mg and Mn. The nutritional composition was determined using standard methods. Free sugars, fatty acids, organic acids, tocopherols, and phenolic compounds were analyzed using various HPLC and GC devises. The extract's antimicrobial, antioxidant, cytotoxicity, and anti-inflammatory activity were assessed. The results indicated that Mg enrichment negatively affected plant growth and mineral accumulation but improved photosynthetic performance. The edible flowers contained significant amounts of protein, low levels of fat, and varying sugar contents, such as glucose and fructose. Various fatty acids and phenolic compounds were identified, with different concentrations depending on the treatment. The flowers exhibited antioxidant potential, antimicrobial activity, cytotoxic effects, and anti-inflammatory properties. The correlations between the investigated parameters not only expand knowledge on Mg and Mn interaction but also catalyze significant advancements in sustainable agriculture and food health, fostering a healthier and more conscious future.

The power of the QUENCHER method in measuring total antioxidant capacity of foods: Importance of interactions between different forms of antioxidants.

Antioxidants play a crucial role in maintaining human health by counteracting oxidative stress and regulating redox balance within the body. The mixture of various antioxidant compounds in different forms (i.e., free, bound, insoluble) in food creates a redox active environment both in the human body and in the food system. Acting as both electron donors and acceptors while interacting with each other can either result in antagonism through pro-oxidative effects, or synergism through regeneration of one antioxidant by another. During the antioxidant capacity measurement, besides the individual antioxidant effects of the antioxidant components, these effects that occur because of their interaction with each other should be also considered. Classical antioxidant capacity measurement methods mostly concentrate on the fractions of foods that can be extracted with either water, alcohol, lipid, or acid/alkaline solutions. Antioxidants that cannot be extracted with any solvent are mostly ignored in these methods. On the other hand, the QUENCHER method, which allows direct measurement of antioxidant capacity foods without extraction, offers a rational solution to the limitations of traditional extraction-based methods. This approach considers the antioxidant capacity and interactions of all antioxidant forms that can be found in a food matrix, at the same time. This review provides detailed insights into the advantages of QUENCHER as a holistic approach for the accurate measurement of the antioxidant capacity of foods.

Evolutions in Commercial Meat Poultry Breeding.

This paper provides a comprehensive overview of the history of commercial poultry breeding, from domestication to the development of science and commercial breeding structures. The development of breeding goals over time, from mainly focusing on production to broad goals, including bird welfare and health, robustness, environmental impact, biological efficiency and reproduction, is detailed. The paper outlines current breeding goals, including traits (e.g., on foot and leg health, contact dermatitis, gait, cardiovascular health, robustness and livability), recording techniques, their genetic basis and how trait these antagonisms, for example, between welfare and production, are managed. Novel areas like genomic selection and gut health research and their current and potential impact on breeding are highlighted. The environmental impact differences of various genotypes are explained. A future outlook shows that balanced, holistic breeding will continue to enable affordable lean animal protein to feed the world, with a focus on the welfare of the birds and a diversity of choice for the various preferences and cultures across the world.

Identifying synergistic combinations of Doxorubicin-Loaded polyquercetin nanoparticles and natural Products: Implications for breast cancer therapy.

Combining chemotherapeutic agents with bioactive natural products is an attractive cancer treatment modality to reduce the dose and side effects of chemotherapy. Combination treatments with drugs having different mechanisms of action can also be beneficial in combatting the development of drug resistance by cancer cells. Nanoparticle (NP)-mediated drug delivery can further improve the therapeutic index of cytotoxic agents by enabling passive and/or active targeting to tumor tissues in vivo. Using doxorubicin (DOX) as a model chemotherapeutic agent, we developed three NP formulations based on polyquercetin (pQCT), an emerging nanocarrier platform. The NPs were co-assembled with DOX, pQCT, and either Pluronic P123, methoxy poly(ethylene glycol)-amine, or D-α-tocopheryl poly(ethylene glycol) 1000 succinate (TPGS). Physicochemical characterization of the NPs revealed them to have a spherical morphology with high monodispersity, excellent drug loading capacity, and sustained drug release. Then, the NPs were evaluated in vitro to determine their potential synergism when combined with the bioactive natural products curcumin (CUR), tannic acid (TA), and thymoquinone (TQ) against breast cancer cells (MCF-7 and MDA-MB-231). Surprisingly, most of the combinations were found to be antagonistic. However, combinations containing CUR exhibited greater pro-apoptotic effects compared to the single agents, with polymer-modified pQCT NPs presenting as a promising nanoplatform for enhancing DOX's ability to promote cancer cell apoptosis. Our findings provide insights into the potential application of pQCT in nanomedicine, as well as the use of bioactive natural products in combination with DOX as a free agent and as an NP formulation in the treatment of breast cancer.

Influence of Molybdenum and Organic Sources of Copper and Sulfur on the Performance, Carcass Traits, Blood Mineral Concentration, and Ceruloplasmin Activity in Lambs.

This study aimed to evaluate the effects of molybdenum (Mo) and organic and inorganic sources of copper (Cu) and sulfur (S) on the performance, carcass traits, and blood concentration of these minerals in lambs. Forty male non-castrated crossbred Dorper x Santa Inês lambs (20 ± 1.2 kg of body weight and 90 ± 2 d of age) were randomly allocated into one of the ten following treatments: (T0) control, basal diet; (T1) Mo; (T2) inorganic Cu and inorganic S; (T3) inorganic Cu and organic S; (T4) organic Cu and inorganic S; (T5) organic Cu and organic S; (T6) Mo plus inorganic Cu and inorganic S; (T7) Mo plus inorganic Cu and organic S; (T8) Mo plus organic Cu and inorganic S; and (T9) Mo plus organic Cu and organic S. Regardless of the source, Mo, Cu, and S were added at levels of 10 mg, 10 mg, and 2000mg/kg DM, respectively. The mineral supplements (Mo, Cu, and S) were added into the total mixed ration (TMR) by mixing them apart with the mineral and vitamin premix and then put into the TMR. The animals were kept in individual pens and received a total mixed ration for 84 days. Body weight and blood sampling was performed every 28 days. All animals were slaughtered after 84 days, and carcass traits were evaluated. Although organic sources of Cu and S added to Mo supplementation had increased the ADG throughout the study, this effect did not reflect in the heavier final BW outcomes for this treatment. In addition, no effect of these treatments was observed on the carcass traits. The serum Cu concentration was higher for the T0 group compared to the other groups; otherwise, Mo reduced the serum Cu concentration compared to the other groups. Considering the interaction among the minerals and their sources at 84 d of study, organic sources of Cu and S treatment and Mo associated with inorganic sources of Cu plus organic S treatment had an increased serum Cu concentration compared to other groups. Regardless of time, organic sources of Cu and S increased serum S concentration. At 84 days after enrollment, serum Mo concentration was lower for the control group compared to the other groups. Further, Mo supplementation increased its blood concentration compared to the control group throughout the study. The control group had the highest ceruloplasmin activity compared to the other groups; otherwise, at 84 d of the study, either Mo or inorganic S supplementation reduced ceruloplasmin activity. Serum ceruloplasmin activity was higher when Cu supplementation, regardless of source, was associated with organic S. However, at d 84 of the study, inorganic Cu associated to organic S supplements increased serum ceruloplasmin activity. In this current study, it was not possible to identify a pattern in the variables studied, however, further studies are needed to confirm that organic sources of Cu and S interacted alone without a defined pattern.

Shuttle between arginine and lysine: influence on cancer immunonutrition.

Amino acids which are essential nutrients for all cell types' survival are also recognised to serve as opportunistic/alternative fuels in cancers auxotrophic for specific amino acids. Accordingly, restriction of amino acids has been utilised as a therapeutic strategy in these cancers. Contrastingly, amino acid deficiencies in cancer are found to greatly impair immune functions, increasing mortality and morbidity rates. Dietary and supplemental amino acids in such conditions have revealed their importance as 'immunonutrients' by modulating cellular homeostasis processes and halting malignant progression. L-arginine specifically has attracted interest as an immunonutrient by acting as a nodal regulator of immune responses linked to carcinogenesis processes through its versatile signalling molecule, nitric oxide (NO). The quantum of NO generated directly influences the cytotoxic and cytostatic processes of cell cycle arrest, apoptosis, and senescence. However, L-lysine, a CAT transporter competitor for arginine effectively limits arginine input at high L-lysine concentrations by limiting arginine-mediated effects. The phenomenon of arginine-lysine antagonism can, therefore, be hypothesised to influence the immunonutritional effects exerted by arginine. The review highlights aspects of lysine's interference with arginine-mediated NO generation and its consequences on immunonutritional and anti-cancer effects, and discusses possible alternatives to manage the condition. However, further research that considers monitoring lysine levels in arginine immunonutritional therapy is essential to conclude the hypothesis.

A review of biocontrol agents in controlling late blight of potatoes and tomatoes caused by Phytophthora infestans and the underlying mechanisms.

Phytophthora infestans causes late blight on potatoes and tomatoes, which has a significant economic impact on agriculture. The management of late blight has been largely dependent on the application of synthetic fungicides, which is not an ultimate solution for sustainable agriculture and environmental safety. Biocontrol strategies are expected to be alternative methods to the conventional chemicals in controlling plant diseases in the integrated pest management (IPM) programs. Well-studied biocontrol agents against Phytophthora infestans include fungi, oomycetes, bacteria, and compounds produced by these antagonists, in addition to certain bioactive metabolites produced by plants. Laboratory and glasshouse experiments suggest a potential for using biocontrol in practical late blight disease management. However, the transition of biocontrol to field applications is problematic for the moment, due to low and variable efficacies. In this review, we provide a comprehensive summary on these biocontrol strategies and the underlying corresponding mechanisms. To give a more intuitive understanding of the promising biocontrol agents against Phytophthora infestans in agricultural systems, we discuss the utilizations, modes of action and future potentials of these antagonists based on their taxonomic classifications. To achieve a goal of best possible results produced by biocontrol agents, it is suggested to work on field trials, strain modifications, formulations, regulations, and optimizations of application. Combined biocontrol agents having different modes of action or biological adaptation traits may be used to strengthen the biocontrol efficacy. More importantly, biological control agents should be applied in the coordination of other existing and forthcoming methods in the IPM programs. © 2023 Society of Chemical Industry.

Anticariogenic Activity of Celastrol and Its Enhancement of Streptococcal Antagonism in Multispecies Biofilm.

Dental caries is a chronic disease resulting from dysbiosis in the oral microbiome. Antagonism of commensal Streptococcus sanguinis and Streptococcus gordonii against cariogenic Streptococcus mutans is pivotal to keep the microecological balance. However, concerns are growing on antimicrobial agents in anticaries therapy, for broad spectrum antimicrobials may have a profound impact on the oral microbial community, especially on commensals. Here, we report celastrol, extracted from Traditional Chinese Medicine's Tripterygium wilfordii (TW) plant, as a promising anticaries candidate. Our results revealed that celastrol showed antibacterial and antibiofilm activity against cariogenic bacteria S. mutans while exhibiting low cytotoxicity. By using a multispecies biofilm formed by S. mutans UA159, S. sanguinis SK36, and S. gordonii DL1, we observed that even at relatively low concentrations, celastrol reduced S. mutans proportion and thereby inhibited lactic acid production as well as water-insoluble glucan formation. We found that celastrol thwarted S. mutans outgrowth through the activation of pyruvate oxidase (SpxB) and H2O2-dependent antagonism between commensal oral streptococci and S. mutans. Our data reveal new anticaries properties of celastrol that enhance oral streptococcal antagonism, which thwarts S. mutans outgrowth, indicating its potential to maintain oral microbial balance for prospective anticaries therapy.

Combinational Effect of Selected Medicinal Plants and Antibiotics Against Pathogenic Bacteria.

<b>Background and Objective:</b> The emergence of antibiotic resistance is a primary global health concern. As a result, there is an urgent need for new strategies to combat antibiotic-resistant bacteria. One of these essential strategies is the combination of medicinal plants and antibiotics as an alternative to using antibiotics alone which was the objective of this article. <b>Materials and Methods:</b> Nine plant materials were collected from different Egypt localities and then extracted by water. Water extracts were filtered and added with Mueller-Hinton agar during preparation. Nine test bacteria and 13 standard antibiotics were used in the disc diffusion sensitivity method. <b>Results:</b> The activity of Amikacin was increased when combined with most different plant extracts against <i>Escherichia coli</i> while antagonistic against <i>Pseudomonas aeruginosa</i>. Aztreonam, Ceftriaxone, Gentamicin and Nalidixic acid antibiotics showed antagonistic or indifferent effects when combined with most different plant extracts against <i>E. coli</i>, <i>Klebsiella pneumonia</i> and <i>P. aeruginosa</i>. The synergistic effect was achieved in Aztreonam when combined with all plant extracts, while Nalidixic acid showed antagonistic when combined with most plant extracts against <i>Proteus mirabilis</i>. The antagonistic effect was achieved in Aztreonam, Ceftriaxone and Nalidixic acid when combined with <i>Achillea fragrantissima</i>, <i>Artemisia monosperma</i> and <i>Leptadenia pyrotechnica</i>, also Aztreonam with <i>Lycium shawii</i> extract against <i>Salmonella typhimurium</i>. The <i>A. fragrantissima</i> and <i>A. monosperma</i> increase the activity of Novobiocin and Vancomycin against <i>Bacillus cereus</i> and Ampicillin and Cefazolin against <i>Staphylococcus aureus</i> but Novobiocin activity increased with most plant extracts against <i>S. aureus</i>. <b>Conclusion:</b> The combinations of antibiotics with the extracts of medicinal plants displayed varying degrees of effects, synergistic, antagonistic and indifferent according to antibiotic type, plant extract and test organism.

Dynamic Modelling to Describe the Effect of Plant Extracts and Customised Starter Culture on Staphylococcus aureus Survival in Goat's Raw Milk Soft Cheese.

This study characterises the effect of a customised starter culture (CSC) and plant extracts (lemon balm, sage, and spearmint) on Staphylococcus aureus (SA) and lactic acid bacteria (LAB) kinetics in goat's raw milk soft cheeses. Raw milk cheeses were produced with and without the CSC and plant extracts, and analysed for pH, SA, and LAB counts throughout ripening. The pH change over maturation was described by an empirical decay function. To assess the effect of each bio-preservative on SA, dynamic Bigelow-type models were adjusted, while their effect on LAB was evaluated by classical Huang models and dynamic Huang-Cardinal models. The models showed that the bio-preservatives decreased the time necessary for a one-log reduction but generally affected the cheese pH drop and SA decay rates (logDref = 0.621-1.190 days; controls: 0.796-0.996 days). Spearmint and sage extracts affected the LAB specific growth rate (0.503 and 1.749 ln CFU/g day-1; corresponding controls: 1.421 and 0.806 ln CFU/g day-1), while lemon balm showed no impact (p > 0.05). The Huang-Cardinal models uncovered different optimum specific growth rates of indigenous LAB (1.560-1.705 ln CFU/g day-1) and LAB of cheeses with CSC (0.979-1.198 ln CFU/g day-1). The models produced validate the potential of the tested bio-preservatives to reduce SA, while identifying the impact of such strategies on the fermentation process.

Selenium in the liver facilitates the biodilution of mercury in the muscle of Planiliza haematocheilus in the Jiaozhou Bay, China.

There are increasing evidences that the biodilution effect can significantly reduce the biomagnification of mercury (Hg) in fish. The significant antagonism of selenium (Se) -Hg may have a potential diluting effect on Hg in fish; however, there is still lack of knowledge on such effect. To reveal the Se-Hg interaction and its role in controlling the biodilution effect of Hg, we investigated levels of Hg and Se in the muscle and liver of redlip mullet from Jiaozhou Bay, China, an urbanized semi-enclosed bay highly impacted by human activities. In general, Hg levels in fish muscle were significantly negatively correlated to the levels of Se in the liver and fish size for fish with a size of < 200 mm, indicating that the antagonistic effect of Se on Hg increased with fish growth. This relationship was not significant for fish with a size of > 200 mm, possibly because the normal metabolism of Hg in muscle was hindered by homeostatic regulation or physiological activities such as gonadal development in vivo. Furthermore, the molar ratio of Se in the liver/Hg in the muscle was significantly increasing with Se/Hg in the liver, suggesting that the liver may be the key organ involved in Se-Hg antagonism. Moreover, both ratios continued to decrease with increasing fish size, implying that the antagonistic effect weakens with fish growth. These results indicate that Hg sequestration by liver may be a key mechanism of Se-Hg antagonism in fish and function as a driver for the biodilution effect of Hg, especially at a size of < 200 mm. These findings are further supported by the established linear model of Se-Hg antagonism at different developmental stages.

Roles of glutathione peroxidase 4 on the mercury-triggered ferroptosis in renal cells: implications for the antagonism between selenium and mercury.

Understanding of how mercury species cause cellular impairments at the molecular level is critical for explaining the detrimental effects of mercury exposure on the human body. Previous studies have reported that inorganic and organic mercury compounds can induce apoptosis and necrosis in a variety of cell types, but more recent advances reveal that mercuric mercury (Hg2+) and methylmercury (CH3Hg+) may result in ferroptosis, a distinct form of programmed cell death. However, it is still unclear which protein targets are responsible for ferroptosis induced by Hg2+ and CH3Hg+. In this study, human embryonic kidney 293T cells were used to investigate how Hg2+ and CH3Hg+ trigger ferroptosis, given their nephrotoxicity. Our results demonstrate that glutathione peroxidase 4 (GPx4) plays a key role in lipid peroxidation and ferroptosis in renal cells induced by Hg2+ and CH3Hg+. The expression of GPx4, the only lipid repair enzyme in mammal cells, was downregulated in response to Hg2+ and CH3Hg+ stress. More importantly, the activity of GPx4 could be markedly inhibited by CH3Hg+, owing to the direct binding of the selenol group (-SeH) in GPx4 to CH3Hg+. Selenite supplementation was demonstrated to enhance the expression and activity of GPx4 in renal cells, and consequently relieve the cytotoxicity of CH3Hg+, suggesting that GPx4 is a crucial modulator implicated in the Hg-Se antagonism. These findings highlight the importance of GPx4 in mercury-induced ferroptosis, and provide an alternative explanation for how Hg2+ and CH3Hg+ induce cell death.

The pollen virome: A review of pollen-associated viruses and consequences for plants and their interactions with pollinators.

The movement of pollen grains from anthers to stigmas, often by insect pollinator vectors, is essential for plant reproduction. However, pollen is also a unique vehicle for viral spread. Pollen-associated plant viruses reside on the outside or inside of pollen grains, infect susceptible individuals through vertical or horizontal infection pathways, and can decrease plant fitness. These viruses are transferred with pollen between plants by pollinator vectors as they forage for floral resources; thus, pollen-associated viral spread is mediated by floral and pollen grain phenotypes and pollinator traits, much like pollination. Most of what is currently known about pollen-associated viruses was discovered through infection and transmission experiments in controlled settings, usually involving one virus and one plant species of agricultural or horticultural interest. In this review, we first provide an updated, comprehensive list of the recognized pollen-associated viruses. Then, we summarize virus, plant, pollinator vector, and landscape traits that can affect pollen-associated virus transmission, infection, and distribution. Next, we highlight the consequences of plant-pollinator-virus interactions that emerge in complex communities of co-flowering plants and pollinator vectors, such as pollen-associated virus spread between plant species and viral jumps from plant to pollinator hosts. We conclude by emphasizing the need for collaborative research that bridges pollen biology, virology, and pollination biology.

Exploration of non-phytopathogenic Aspergillus spp. isolates recovered from soil and compost as potential source of bioactive metabolites for potato Fusarium dry rot control.

During storage, infected potato tubers by Fusarium species leads to significant losses. Searching natural-based alternatives to chemical fungicides for the control of tuber dry rot pathogens is becoming essential. Nine Aspergillus spp. (A. niger, A. terreus, A. flavus, and Aspergillus sp.) isolates, recovered from soil and compost samples, were explored and evaluated for their ability to suppress Fusarium sambucinum the main causal agent of potato tuber dry rot disease in Tunisia. All conidial suspensions of Aspergillus spp. tested and their cell-free culture filtrates had significantly inhibited the in vitro pathogen growth by 18.5 to 35.9% and by 9 to 69% compared to control, respectively. A. niger CH12 cell-free filtrate was the most active against F. sambucinum at the three concentration tested (10, 15, and 20% v v-1). Chloroform and ethyl acetate extracts from four Aspergillus spp., tested at 5% v v-1, had limited F. sambucinum mycelial growth by 34-60% and 38-66%, respectively, compared to control, with A. niger CH12 ethyl extract being the most active. Tested on potato tubers inoculated with F. sambucinum, all tested Aspergillus spp. isolates, their cell-free filtrates and organic extracts had significantly decreased the external diameter of dry rot lesion compared to pathogen-inoculated and untreated control tubers. For the rot penetration, all Aspergillus spp. isolates, their organic extracts and only filtrates from A. niger CH12 and MC2 isolates had significantly limited dry rot severity compared to pathogen-inoculated and untreated control. The highest reductions in the external diameter of dry rot lesion (76.6 and 64.1%) and the average rot penetration (77.1 and 65.1%) were achieved using chloroform and ethyl acetate extracts from A. niger CH12, respectively. These results clearly demonstrated the presence of bioactive compounds in Aspergillus spp. that can be extracted and explored as an eco-friendly alternative for the control of the target pathogen.

Azospirillum-Bacillus associations: synergistic effects on in vitro PGP traits and growth of pearl millet at early seedling stage under limited moisture conditions.

The association of plant beneficial Azospirillum and Bacillus spp. strains expressing different sets of PGP traits may have complementary or supplementary effects on host plants. In the present investigation, A. formosense and Bacillus spp. strains showing diverse PGP traits (IAA production, nitrogenase activity, phosphate, zinc and potassium solubilization, siderophores, antagonism against phytopathogens, osmotic stress tolerance, etc.) were assessed for compatibility by cross-streaking and co-culturing. Under co-culture (Azospirillum + Bacillus), a significant increase in the expression of PGP traits, nitrogenase activity (up to 89%), phosphate solubilization (upto 236%), siderophore production (upto 20%) was observed as compared to individual Azospirillum culture, indicating synergistic effect of co-culture. IAA production was higher in Azospirillum sp. strains as compared to Bacillus spp. strains, when cultured individually; however, when co-cultured, the IAA levels were in the mid-range indicating the contributory effects of compatible strains. The effect of individual Azospirillum and Bacillus strains and their co-inoculation was also assessed on the growth of pearl millet at early stages under moisture-deficit stress imposed using PEG6000 (0, 10, and 20%). Co-inoculation enhanced seed germination (up to 10, 3, and 6% increase under 0, 10, and 20% PEG, respectively, over individual Azospirillum treatment), root traits (increased root hair density and lateral branches), and seedling vigor indices (up to 22, 32, 43% increase in seed vigor index I and 8, 14, and 10% increase in seed vigor index II under 0, 10, 20% PEG, respectively, over individual Azospirillum treatment) under normal as well as moisture-deficit conditions suggesting the role of Bacillus spp. strains in better adaptation of the plants to stress and higher yield potential. The synergistic effect of co-cultured Azospirillum and Bacillus strains on PGP traits indicated metabolic interplay between the two strains which needs to be further understood. The positive effect of co-inoculation on plant growth under moisture-deficit stress indicated the promise of Azospirillum and Bacillus as a synergistic bioformulation for combating nutrient and drought stress in pearl millet, particularly in nutrient-poor dryland agricultural systems. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-023-03503-4.