Inoculation with Bacillus megaterium CNPMS B119 and Bacillus subtilis CNPMS B2084 improve P-acquisition and maize yield in Brazil.

Phosphorus (P) is a critical nutrient for plant growth, yet its uptake is often hindered by soil factors like clay minerals and metal oxides such as aluminum (Al), iron (Fe), and calcium (Ca), which bind P and limit its availability. Phosphate-solubilizing bacteria (PSB) have the unique ability to convert insoluble P into a soluble form, thereby fostering plant growth. This study aimed to assess the efficacy of inoculation of Bacillus megaterium B119 (rhizospheric) and B. subtilis B2084 (endophytic) via seed treatment in enhancing maize yield, grain P content, and enzyme activities across two distinct soil types in field conditions. Additionally, we investigated various mechanisms contributing to plant growth promotion, compatibility with commercial inoculants, and the maize root adhesion profile of these strains. During five crop seasons in two experimental areas in Brazil, Sete Lagoas-MG and Santo Antônio de Goiás-GO, single inoculations with either B119 or B2084 were implemented in three seasons, while a co-inoculation with both strains was applied in two seasons. All treatments received P fertilizer according to plot recommendations, except for control. Both the Bacillus strains exhibited plant growth-promoting properties relevant to P dynamics, including phosphate solubilization and mineralization, production of indole-3-acetic acid (IAA)-like molecules, siderophores, exopolysaccharides (EPS), biofilms, and phosphatases, with no antagonism observed with Azospirillum and Bradyrizhobium. Strain B2084 displayed superior maize root adhesion compared to B119. In field trials, single inoculations with either B119 or B2084 resulted in increased maize grain yield, with relative average productivities of 22 and 16% in Sete Lagoas and 6 and 3% in Santo Antônio de Goiás, respectively. Co-inoculation proved more effective, with an average yield increase of 24% in Sete Lagoas and 11% in Santo Antônio de Goiás compared to the non-inoculated control. Across all seasons, accumulated grain P content correlated with yield, and soil P availability in the rhizosphere increased after co-inoculation in Santo Antônio de Goiás. These findings complement previous research efforts and have led to the validation and registration of the first Brazilian inoculant formulated with Bacillus strains for maize, effectively enhancing and P grain content.

Inhibitory activity of bacterial lipopeptides against Fusarium oxysporum f.sp. Strigae.

This study investigated the influence of bacterial cyclic lipopeptides (LP; surfactins, iturins, fengycins) on microbial interactions. The objective was to investigate whether the presence of bacteria inhibits fungal growth and whether this inhibition is due to the release of bacterial metabolites, particularly LP. Selected endophytic bacterial strains with known plant-growth promoting potential were cultured in the presence of Fusarium oxysporum f.sp. strigae (Fos), which was applied as model fungal organism. The extracellular metabolome of tested bacteria, with a focus on LP, was characterized, and the inhibitory effect of bacterial LP on fungal growth was investigated. The results showed that Bacillus velezensis GB03 and FZB42, as well as B. subtilis BSn5 exhibited the strongest antagonism against Fos. Paraburkholderia phytofirmans PsJN, on the other hand, tended to have a slight, though non-significant growth promotion effect. Crude LP from strains GB03 and FZB42 had the strongest inhibitory effect on Fos, with a significant inhibition of spore germination and damage of the hyphal structure. Liquid chromatography tandem mass spectrometry revealed the production of several variants of iturin, fengycin, and surfactin LP families from strains GB03, FZB42, and BSn5, with varying intensity. Using plate cultures, bacillomycin D fractions were detected in higher abundance in strains GB03, FZB42, and BSn5 in the presence of Fos. Additionally, the presence of Fos in dual plate culture triggered an increase in bacillomycin D production from the Bacillus strains. The study demonstrated the potent antagonistic effect of certain Bacillus strains (i.e., GB03, FZB42, BSn5) on Fos development. Our findings emphasize the crucial role of microbial interactions in shaping the co-existence of microbial assemblages.

Effect of different inoculation strategies of mixed culture Saccharomyces cerevisiae/Oenococcus oeni on the aroma quality of Chardonnay wine.

There has been growing interest in the use of mixed cultures comprised of Oenococcus oeni and Saccharomyces cerevisiae to produce wine with local style and typicality. This study has investigated the influence of the inoculation protocol of O. oeni on the fermentation kinetics and aromatic profile of Chardonnay wine. The one selected autochthonous O. oeni strain (ZX-1) inoculated at different stages of the alcoholic fermentation process successfully completed malolactic fermentation (MLF). Co-inoculum of S. cerevisiae and O. oeni enabled simultaneous alcoholic fermentation and MLF, leading to at least a 30 % reduction in the total fermentation time when compared to the sequential inoculation process, which was attributed to the lower ethanol stress. Meanwhile, co-inoculum stimulated the accumulation of volatile aroma compounds in Chardonnay wine. In particular, the mixed modality where the O. oeni strain ZX-1 was inoculated 48 h after S. cerevisiae allowed higher levels of terpenes, acetates, short-chain, and medium-chain fatty acid ethyl esters to be produced, which may result in the enhanced floral and fruity attributes of wine. Aroma reconstitution and omission models analysis revealed that the accumulation of linalool, geraniol, isoamyl acetate, ethyl hexanoate, and ethyl caprylate during the mixed fermentation process enhanced the stone fruit, tropical fruit, and citrus aromas in Chardonnay wine. Therefore, the simultaneous fermentation of S. cerevisiae and autochthonous O. oeni ZX-1 has a positive effect on MLF and contributes to producing wines with distinctive style.

Pathophysiology and transcriptomic responses of Pinus armandii defenses to ophiostomatoid fungi.

Pinus armandii Franch. is an ecologically and economically important evergreen tree species native to western China. Dendroctonus armandi Tsai and Li and pathogenic ophiostomatoid fungi pose substantial threats to P. armandii. With the interplay between species, the defense mechanisms of P. armandii have evolved to withstand external biotic stressors. However, the interactions between P. armandii and pathogenic ophiostomatoid fungal species/strains remain poorly understood. We aimed to analyze the pathophysiological and molecular changes in P. armandii following artificial inoculation with four ophiostomatoid species (Graphilbum parakesiyea, Leptographium qinlingense, Ophiostoma shennongense and Ophiostoma sp. 1). The study revealed that L. qinlingense produced the longest necrotic lesions, and G. parakesiyea produced the shortest. All strains induced monoterpenoid release, and monoterpene levels of P. armandii were positively correlated with fungal virulence (R2 = 0.93, P < 0.01). Co-inoculation of two dominant highly (L. qinlingense) and weakly virulent (O. shennongense) pathogens reduced the pathogenicity of the highly virulent fungi. Transcriptomic analysis of P. armandii (LQ: L. qinlingense treatments, QS: co-inoculation treatments and OS: O. shennongense treatments) showed that the expression pattern of differentially expressed genes (DEGs) between QS and OS was similar, but different from that of LQ. The DEGs (LQ vs QS) involved in flavonoid biosynthesis and phenylpropanoid biosynthesis were downregulated. Notably, compared with LQ, QS significantly decreased the expression of host defense-related genes. This study provides a valuable theoretical basis for managing infestations of D. armandi and associated ophiostomatoid fungi.

Co-inoculation of fungi and desert cyanobacteria facilitates biological soil crust formation and soil fertility.

The inoculation of cyanobacteria for enriching soil nutrients and forming biological soil crusts (BSCs) is considered an effective means to restore degraded soil. However, there are limited studies on the application of co-inoculation of fungi and cyanobacteria for degraded soil remediation. In this study, a high exopolysaccharide-secreting fungi Zh2 was isolated from lichen BSCs in Hobq Desert, and co-inoculated with a cyanobacterial strain identified as Phormidium tenue in different proportions to form BSCs on sand during a 35 days incubation period. Results revealed significant differences in crust biomass and soil properties among crusts with different cyanobacterial/fungal inoculation ratios. Microbial biomass, soil nutrient content and enzyme activities in crusts co-inoculated with cyanobacteria and fungi were higher than those inoculated with cyanobacteria and fungi alone. The inoculation of cyanobacteria contributed to the fulvic-like accumulation, and the inoculated fungi significantly increased the humic-like content and soil humification. Redundancy analysis showed that the inoculation of cyanobacteria was positively correlated with the activities of urease and phosphatase, and the content of fulvic-like. Meanwhile, the inoculation of fungi was positively correlated with the contents of total carbon, total nitrogen and humic-like, the activities of catalase and sucrase. Cyanobacteria and fungi play distinct roles in improving soil fertility and accumulating dissolved organic matter. This study provides new insights into the effects of cyanobacteria and fungi inoculations on the formation and development of cyanobacterial-fungus complex crusts, offering a novel method for accelerating induced crust formation on the surface of sand.

An overview of Parafrankia (Nod+/Fix+) and Pseudofrankia (Nod+/Fix-) interactions through genome mining and experimental modeling in co-culture and co-inoculation of Elaeagnus angustifolia.

In many frankia, the ability to nodulate host plants (Nod+) and fix nitrogen (Fix+) is a common strategy. However, some frankia within the Pseudofrankia genus lack one or two of these traits. This phenomenon has been consistently observed across various actinorhizal nodule isolates, displaying Nod- and/or Fix- phenotypes. Yet, the mechanisms supporting the colonization and persistence of these inefficient frankia within nodules, both with and without symbiotic strains (Nod+/Fix+), remain unclear. It is also uncertain whether these associations burden or benefit host plants. This study delves into the ecological interactions between Parafrankia EUN1f and Pseudofrankia inefficax EuI1c, isolated from Elaeagnus umbellata nodules. EUN1f (Nod+/Fix+) and EuI1c (Nod+/Fix-) display contrasting symbiotic traits. While the prediction suggests a competitive scenario, the absence of direct interaction evidence implies that the competitive advantage of EUN1f and EuI1c is likely contingent on contextual factors such as substrate availability and the specific nature of stressors in their respective habitats. In co-culture, EUN1f outperforms EuI1c, especially under specific conditions, driven by its nitrogenase activity. Iron-depleted conditions favor EUN1f, emphasizing iron's role in microbial competition. Both strains benefit from host root exudates in pure culture, but EUN1f dominates in co-culture, enhancing its competitive traits. Nodulation experiments show that host plant preferences align with inoculum strain abundance under nitrogen-depleted conditions, while consistently favoring EUN1f in nitrogen-supplied media. This study unveils competitive dynamics and niche exclusion between EUN1f and EuI1c, suggesting that host plant may penalize less effective strains and even all strains. These findings highlight the complex interplay between strain competition and host selective pressure, warranting further research into the underlying mechanisms shaping plant-microbe-microbe interactions in diverse ecosystems. IMPORTANCE: While Pseudofrankia strains typically lack the common traits of ability to nodulate the host plant (Nod-) and/or fix nitrogen (Fix-), they are still recovered from actinorhizal nodules. The enigmatic question of how and why these unconventional strains establish themselves within nodule tissue, thriving either alongside symbiotic strains (Nod+/Fix+) or independently, while considering potential metabolic costs to the host plant, remains a perplexing puzzle. This study endeavors to unravel the competitive dynamics between Pseudofrankia inefficax strain EuI1c (Nod+/Fix-) and Parafrankia strain EU1Nf (Nod+/Fix+) through a comprehensive exploration of genomic data and empirical modeling, conducted both in controlled laboratory settings and within the host plant environment.

Responses and resistance capacity of Solanum nigrum L. mediated by three ecological category earthworms in metal-[Cd-As-Cu-Pb]-contaminated soils of North China.

Earthworms play vital functions affecting plant growth and metal accumulation from downground to aboveground. Soil metal mobilization may be combined with use of earthworm and hyperaccumulator-Solanum nigrum to improve its remediation efficiency. Understanding the effects of specific-species earthworm belonging to different ecological categories on mechanisms underlying of S. nigrum is critical for metal-polluted remediation. However, seldom studies concerned earthworm-assisted phytoremediation of metal contaminated soil in Northern China. This study investigated the effects of earthworm (Eisenia fetida, Amynthas hupeiensis and Drawida gisti) on S. nigrum with exposure to uncontaminated and [Cd-As-Cu-Pb]-contaminated soil (referred to as S0 and S1) for 60 days, respectively. In S1 soil, A. hupeiensis (anecic) had stronger effects on growth and metal accumulation in the organs (root, stem, and leaf) of S. nigrum than D. gisti (endogeic) and E. fetida (epigeic), attributing to their ecological category. The BAF values of S. nigrum were generally ranking in Cd (0.66-5.13) > As (0.03-1.85) > Cu (0.03-0.06) > Pb (0.01-0.05); the BAFCd values were ranking in leaf (2.34-5.13) > root (1.96-4.14) > stem (0.66-1.33); BAFAs, BAFCu, and BAFPb were root (0.04-1.63) > stem (0.01-0.09) ≈ leaf (0.01-0.06). A. hupeiensis decreased the TF values of S. nigrum from the roots to the shoots. Co-effects of metal stress and earthworm activity on metal uptake by shoots suggested that A. hupeiensis increased the uptake of As, Cu, and Pb (by 56.3 %, 51.5 %, and 16.2 %, p < 0.05), but not Cd, which appeared to remain steady for prolonged durations. Alterations in the integrated biomarker response index version 2 (IBRv2) values demonstrated that A. hupeiensis (12.65) improved the resistance capacity (stimulated GSH, SnGS1, and SnCu-SOD) of S. nigrum under metal-containing conditions, compared with E. fetida and D. gisti (IBRv2 were 9.61 and 9.11). This study may provide insights into the patterns of 'soil-earthworm-plant system' on improving remediation efficiency of S. nigrum, from the perspective of earthworm ecological niche partitioning.

The Efficacy of Selected Probiotic Strains and Their Combination to Inhibit the Interaction of Adherent-Invasive Escherichia coli (AIEC) with a Co-Culture of Caco-2:HT29-MTX Cells.

The gastrointestinal tract's microbiota plays a crucial role in human health, with dysbiosis linked to the development of diseases such as inflammatory bowel disease (IBD). Whilst the pathogenic mechanisms underlying IBD remain poorly characterised, adherent-invasive Escherichia coli (AIEC) has been implicated as a microbiological factor in disease pathogenesis. These strains show an enhanced ability to diffusely adhere to and invade intestinal epithelial cells, along with the ability to survive and replicate within macrophages. Probiotics, such as Lactobacillus strains, have been identified as potential treatment options due to their abilities to compete with pathogens for binding sites and regulate the host immune response. In this study, we used four well-characterised Lactobacillus strains and their combination to test their ability to inhibit the adhesion, invasion, and translocation of a well-characterized AIEC strain, F44A-1, in a co-culture of Caco-2 and HT29-MTX cell lines representing the gut epithelium. The results demonstrated that the pre-inoculation of the probiotic candidates 90 min prior to the introduction of the AIEC was more effective in inhibiting AIEC interaction than the co-inoculation of the strains. While the individual probiotic strains greatly reduced AIEC colonisation and invasion of the co-cultured cells, their combination was only more effective in reducing the translocation of the AIEC. These results suggest that probiotics are more effective when used prophylactically against pathogens and that the combination of strains may enhance their efficacy against AIEC translocation once used as a prophylactic measure.

Interaction of Zinc Mineral Nutrition and Plant Growth-Promoting Bacteria in Tropical Agricultural Systems: A Review.

The relationship between zinc mineral nutrition and plant growth-promoting bacteria (PGPB) is pivotal in enhancing agricultural productivity, especially in tropical regions characterized by diverse climatic conditions and soil variability. This review synthesizes and critically evaluates current knowledge regarding the synergistic interaction between zinc mineral nutrition and PGPB in tropical agricultural systems. Zinc is an essential and fundamental micronutrient for various physiological and biochemical processes in plants. Its deficiency affects plant growth and development, decreasing yields and nutritional quality. In tropical regions, where soil zinc availability is often limited or imbalanced, the PGPB, through different mechanisms such as Zn solubilization; siderophore production; and phytohormone synthesis, supports Zn uptake and assimilation, thereby facilitating the adverse effects of zinc deficiency in plants. This review outlines the impacts of Zn-PGPB interactions on plant growth, root architecture, and productivity in tropical agricultural systems. The positive relationship between PGPB and plants facilitates Zn uptake and improves nutrient use efficiency, overall crop performance, and agronomic biofortification. In addition, this review highlights the importance of considering indigenous PGPB strains for specific tropical agroecosystems, acknowledging their adaptability to local conditions and their potential in sustainable agricultural practices. It is concluded that Zn fertilizer and PGPBs have synergistic interactions and can offer promising avenues for sustainable agriculture, addressing nutritional deficiencies, improving crop resilience, and ensuring food security.

Investigation of volatile compounds during fermentation of Elaeagnus moorcroftii Wall.ex schlecht. juice by Bifidobacterium animalis subsp. lactis HN-3 and Lacticaseibacillus paracasei YL-29.

The influence on and biotransformation of volatile compounds (VOCs) during fermentation of Elaeagnus moorcroftii Wall.ex Schlecht. juice (EWSJ) through single inoculation and co-inoculation of Bifidobacterium animalis subsp. lactis HN-3 (B.an3) and Lacticaseibacillus paracasei YL-29 (L.cp29) were analyzed through headspace-solid phase microextraction-gas chromatography-mass spectrometry. Compared with the B.an3- and L.cp29-fermented EWSJ, the B.an3 + L.cp29-fermented EWSJ had more increased 9 desirable flavor compositions and less decreased in or even elimination of 12 undesirable flavor compositions, and 3 new characteristic VOCs, formed through the interaction between B.an3 and L.cp29 were detected. In addition, biotransformations that led to an increase and a decrease in VOCs mainly involved 3 oxidation, 3 reduction, 1 hydrolysis, and 1 isomerization reactions. This study offers a theoretical basis for investigating the interaction effect of Lactobacillus and Bifidobacterium species on VOCs and developing lactic acid bacteria-fermented plant-based juices with lower sugar content and better flavor.

Selecting autochthonous lactic acid bacteria for co-inoculation in Chinese bayberry wine production: Stress response, starter cultures application and volatilomic study.

This study focused on isolating and characterising autochthonous lactic acid bacteria (LAB) from spontaneously fermented Chinese bayberry (CB) and their potential application in CB wine fermentation in co-inoculation with yeast starter cultures. Numerous LAB, including Lactiplantibacillus (Lp.) plantarum (9), Limosilactobacillus (Lb.) fermentum (6), Lactococcus (Lc.) lactis (3), Enterococcus (Ec.) hirae (1), Leuconostoc (Le.) mesenteroides (1), and Weissella (Ws.) cibaria (1), were isolated and identified. The isolated strains Lp. plantarum ZFM710 and ZFM715, together with Lb. fermentum ZFM720 and ZFM722, adapted well to unfavourable fermentation environment, including ethanol, osmolality, and acidity stresses, were selected for producing CB wine by co-inoculation with Saccharomyces cerevisiae. During fermentation, the presence of LAB promoted the development of S. cerevisiae, while the population dynamics of LAB in different groups at different stages showed strain-specific differences. Fermentation trials involving LAB yielded a lower ethanol concentration except for Lp. plantarum ZFM715. Compared to the pure S. cerevisiae fermented sample, the addition of LAB led to a clear modulation in organic acid composition. Lb. fermentum strains in co-fermentation led to significant decreases in each classified group of aroma compounds, while Lp. plantarum ZFM715 significantly increased the complexity and intensity of aroma compounds, as well as the intensities of fruity and floral notes. The study selects interesting strains for the design of starter cultures for use in CB wine production, underlining the interest in the selection of autochthonous LAB in fruit wines, with the aim of improving the adaptation of bacteria to specific environmental conditions and shaping the unique traits of the finished products.

Inter-species interactions between two bacterial flower commensals and a floral pathogen reduce disease incidence and alter pathogen activity.

Flowers are colonized by a diverse community of microorganisms that can alter plant health and interact with floral pathogens. Erwinia amylovora is a flower-inhabiting bacterium and a pathogen that infects different plant species, including Malus × domestica (apple). Previously, we showed that the co-inoculation of two bacterial strains, members of the genera Pseudomonas and Pantoea, isolated from apple flowers, reduced disease incidence caused by this floral pathogen. Here, we decipher the ecological interactions between the two flower-associated bacteria and E. amylovora in field experimentation and in vitro co-cultures. The two flower commensal strains did not competitively exclude E. amylovora from the stigma habitat, as both bacteria and the pathogen co-existed on the stigma of apple flowers and in vitro. This suggests that plant protection might be mediated by other mechanisms than competitive niche exclusion. Using a synthetic stigma exudation medium, ternary co-culture of the bacterial strains led to a substantial alteration of gene expression in both the pathogen and the two microbiota members. Importantly, the gene expression profiles for the ternary co-culture were not just additive from binary co-cultures, suggesting that some functions only emerged in multipartite co-culture. Additionally, the ternary co-culture of the strains resulted in a stronger acidification of the growth milieu than mono- or binary co-cultures, pointing to another emergent property of co-inoculation. Our study emphasizes the critical role of emergent properties mediated by inter-species interactions within the plant holobiont and their potential impact on plant health and pathogen behavior. IMPORTANCE: Fire blight, caused by Erwinia amylovora, is one of the most important plant diseases of pome fruits. Previous work largely suggested plant microbiota commensals suppressed disease by antagonizing pathogen growth. However, inter-species interactions of multiple flower commensals and their influence on pathogen activity and behavior have not been well studied. Here, we show that co-inoculating two bacterial strains that naturally colonize the apple flowers reduces disease incidence. We further demonstrate that the interactions between these two microbiota commensals and the floral pathogen led to the emergence of new gene expression patterns and a strong alteration of the external pH, factors that may modify the pathogen's behavior. Our findings emphasize the critical role of emergent properties mediated by inter-species interactions between plant microbiota and plant pathogens and their impact on plant health.

Impact of antagonistic endophytic bacteria on productivity of some economically important legumes.

Understanding the interactions within and between endophytes and their hosts is still obscure. Investigating endophytic bacterial plant growth-promoting (PGP) traits and co-inoculation effects on legumes' performance is a candidate. Endophytic bacteria were isolated from Vicia sativa root nodules. Such endophytes were screened for their PGP traits, hydrolytic enzymes, and antifungal activities. Sterilized Vicia faba and Pisum sativum seedlings were co-inoculated separately with seven different endophytic bacterial combinations before being planted under sterilized conditions. Later on, several growth-related traits were measured. Eleven endophytes (six rhizobia, two non-rhizobia, and three actinomycetes) could be isolated, and all of them were indole-acetic-acid (IAA) producers, while seven isolates could solubilize phosphorus, whereas three, five, five, and four isolates could produce protease, cellulase, amylase, and chitinase, respectively. Besides, some of these isolates possessed powerful antifungal abilities against six soil-borne pathogenic fungi. Co-inoculation of tested plants with endophytic bacterial mixes (Rhizobiamix+Actinomix+non-Rhizobiamix), (Rhizobiamix+Actinomix), or (Rhizobiamix+non-Rhizobiamix) significantly improved the studied growth parameters (shoot, root fresh and dry weights, length and yield traits) compared to controls, whereas co-inoculated plants with (Rhizobiaalone), (non-Rhizobiamix), or (Actinomix) significantly recorded lower growth parameters. Five efficient endophytes were identified: Rhizobium leguminosarum bv. Viciae, Rhizobium pusense, Brevibacterium frigoritolerans, Streptomyces variabilis, and Streptomyces tendae. Such results suggested that these isolates could be utilized as biocontrols and biofertilizers to improve legumes productivity. Also, co-inoculation with different endophytic mixes is better than single inoculation, a strategy that should be commercially exploited.

The co-inoculation of Trichoderma viridis and Bacillus subtilis improved the aerobic composting efficiency and degradation of lignocellulose.

The aim of this study was to reveal the mechanism by which co-inoculation with both Trichoderma viridis and Bacillus subtilis improved the efficiency of composting and degradation of lignocellulose in agricultural waste. The results showed that co-inoculation with Trichoderma and Bacillus increased abundance of Bacteroidota to promote the maturation 7 days in advance. Galbibacter may be a potential marker of co-inoculation composting efficiency compost. The compost became dark brown, odorless, and had a carbon to nitrogen ratio of 16.40 and a pH of 8.2. Moreover, Actinobacteriota and Firmicutes still dominated the degradation of lignocellulose following inoculation with Trichoderma or Bacillus 35 days after composting. Bacterial function prediction analysis showed that carbohydrate metabolism was the primary metabolic pathway. In conclusion, co-inoculation with Trichoderma and Bacillus shortened the composting cycle and accelerated the degradation of lignocellulose. These findings provide new strategies for the efficient use of agricultural waste to produce organic fertilizers.

Strategies on aroma formation in Chardonnay sparkling base wine: Different Saccharomyces cerevisiae strains, co-inoculation with Torulaspora delbrueckii and utilization of bentonite.

The worldwide production of sparkling wines has been growing annually, driven by a market demand for high quality and more complex products. The present study aimed to evaluate the fermentation of Chardonnay must using two different Saccharomyces cerevisiae yeasts, either alone (from commercial brands A and B) or in combination with Torulaspora delbrueckii (ScA + Td and ScB + Td, respectively), as well as the addition of bentonite to the fermentation with ScA (ScA + Ben), to investigate their impact on aroma formation in sparkling base wine. Enological parameters, volatile composition, and sensory profile were evaluated. The results showed notable differences in total sulfur dioxide and volatile acidity among the S. cerevisiae strains. Moreover, the esters ethyl acetate, isoamyl acetate, hexyl acetate, and phenethyl acetate showed significant differences among treatments. Esters are recognized for their contribution to fruity and floral aromas, making them an essential part of the aromatic profile of wines. The descriptive analysis revealed that ScB + Td had the highest intensity of floral and tropical fruit notes, as well as aromatic clarity. The use of bentonite did not affect the aromatic composition or sensory profile of the wine. Therefore, the co-inoculation of S. cerevisiae with T. delbrueckii can lead to a base wine with a higher intensity of important volatile compounds and sensory attributes, providing an important alternative to produce winery products with a more complex aroma profile.

Co-inoculation effects of B. licheniformis and P. aeruginosa on soil Cd and As availability and rice accumulation.

There have been studies reporting the effects of multiple bacterial strains on the Cd/As immobilization and transformation in culture media. However, there is limited research to validate the effects of microbial strain combination on plant Cd/As accumulation and antioxidant system in the soil-plant system. By planting the rice (Zhefu 7) with the co-inoculation of bacterial strains (i.e. Bacillus licheniformis and Pseudomonas aeruginosa) after two months with the contaminations of Cd (2 mg/kg), As (80 mg/kg) and Cd + As (2 + 80 mg/kg), we found that the bacterial co-inoculation decreased Cd concentrations in the rhizosphere soil porewater, but had limited effects on mitigating plant Cd accumulation. By contrast, the co-inoculation did not affect the As(III) and As(V) concentrations in the rhizosphere soil porewater, but decreased As(III) and As(V) concentrations by 17% and 17% in the root respectively and by 17% and 37% in rice shoot respectively. Using DNA sequencing, we found the increased abundance in both exogenous Bacillus licheniformis and native microorganisms, indicating that the added strains had synergetic interactions with soil native microorganisms. Regarding on plant antioxidant enzyme system, the bacterial co-inoculation decreased the concentrations of superoxide dismutase (SOD), hydrogen peroxide (H2O2) and malondialdehyde (MDA) by 75%, 74% and 22%, mitigating the As damage to rice root and promote plant growth. However, under Cd and As co-stress, the effects of co-inoculation on mitigating plant As accumulation and enhancing plant stress resistance appear to be diminished. Our findings underscore the importance of microbial co-inoculation in reducing plant As accumulation and preserving plant health under heavy metal stress.

Protein profile and volatile compound associated with fermented coffees with yeast co-inoculation.

This work aims to analyze the protein profile and volatile compounds of coffees fermented with the indigenous microbiota and with the co-inoculation of three yeasts (Saccharomyces cerevisiae, Torulaspora delbrueckii, and Candida parapsilosis). Two-dimensional gel electrophoresis (2D-PAGE), MALDI-ToF/ToF (MS/MS), and gas chromatography (GC-MS) were performed. A total of 72 "spots" were detected by 2D-PAGE. 16 spots were selected for identification by MALDI-ToF/ToF, and 12 were identified (11S protein, 13S globulin basic chain, 17.6 kDa class II heat shock protein (HSP17.6-CII), 18.0 kDa class I heat shock protein, Seed of Late Development Stage, Pru ar 1, and FAR-1 protein). 81 main volatile compounds were detected and classified into alcohols, acids, aldehydes, esters, hydrocarbons, pyrazines, furans, thiols, and pyridines/pyrrols. The difference between the identified volatile compounds and their concentrations was detected in the treatments with and without inoculation after drying. The compounds formed in green coffee during fermentation can participate in several reactions during roasting, presenting different sensory profiles and contributing to coffee quality.

PGPR-Soil Microbial Communities' Interactions and Their Influence on Wheat Growth Promotion and Resistance Induction against Mycosphaerella graminicola.

The efficiency of plant-growth-promoting rhizobacteria (PGPR) may not be consistently maintained under field conditions due to the influence of soil microbial communities. The present study aims to investigate their impact on three PGPR-based biofertilizers in wheat. We used the PGPR Paenibacillus sp. strain B2 (PB2), PB2 in co-inoculation with Arthrobacter agilis 4042 (Mix 2), or with Arthrobacter sp. SSM-004 and Microbacterium sp. SSM-001 (Mix 3). Inoculation of PB2, Mix 2, and Mix 3 into non-sterile field soil had a positive effect on root and aboveground dry biomass, depending on the wheat cultivar. The efficiency of the PGPR was further confirmed by the protection they provided against Mycosphaerella graminicola, the causal agent of Septoria leaf blotch disease. PB2 exhibited protection of ≥37.8%, while Mix 2 showed ≥47.9% protection in the four cultivars tested. These results suggest that the interactions between PGPR and native soil microbial communities are crucial for promoting wheat growth and protection. Additionally, high-throughput sequencing of microbial communities conducted 7 days after PGPR inoculations revealed no negative effects of PB2, Mix 2, and Mix 3 on the soil microbial community structure. Interestingly, the presence of Arthrobacter spp. appeared to mitigate the potential negative effect of PB2 on bacterial community and foster root colonization by other beneficial bacterial strains.

Characteristics and Pathogenicity of Discula theae-sinensis Isolated from Tea Plant (Camellia sinensis) and Interaction with Colletotrichum spp.

Anthracnose is one of the primary diseases in tea plants that affect tea yield and quality. The geographical distribution, occurrence regularity, and agronomic measures of tea plants with anthracnose have been researched for decades. However, the pathogenic cause of anthracnose in tea plants is diverse in different regions of the world. Identifying the specific pathogenic fungi causing tea anthracnose is an essential control measure to mitigate this disease. In this study, 66 Discula theae-sinensis and 45 Colletotrichum isolates were obtained from three different types of diseased tea leaves. Based on multilocus phylogenetic and morphological analysis, eight known species of Colletotrichum, Colletotrichum fructicola, C. camelliae, C. aenigma, C. siamense, C. henanense, C. karstii, C. tropicicola, and C. gigasporum were identified. This study is the first to report C. tropicicola and C. gigasporum in tea plants in China. Discula theae-sinensis was the most common species in this study and caused disease lesions around wounded areas of tea leaves. The dual trials in vitro indicated Discula theae-sinensis and Colletotrichum were slightly inhibited. Co-inoculating Discula theae-sinensis and C. fructicola was superior to single inoculation at low concentrations. The main cause of anthracnose might be the concerted action of a variety of fungi.

Co-Inoculation of Non-Symbiotic Bacteria Bacillus and Paraburkholderia Can Improve the Soybean Yield, Nutrient Uptake, and Soil Parameters.

Due to its nutritional value and oil, soybean (Glycine max L.) became an economic crop in India and worldwide. The current study investigated the effect of forest-associated plant growth-promoting rhizobacteria (PGPR) on soybean yield and grain nutrient content. Five potential bacteria were used in this study based on their PGPR traits. The pot assay result with two crops (soybean and chickpea) confirmed the growth promotion activity of the two strains (Bacillus subtilis MpS15 and Paraburkholderia sabiae NvS21). The result showed significant (p < 0.05) enhancement in plant length and biomass with the seed treatment with strains (MpS15 and NvS21) compared to the control. Later both biocompatible potential strains were used in field experiments as individuals and consortia. Seed treatment of consortia significantly improves the nodulation and photosynthetic content more than individual treatments and control. Compared to the control, the co-inoculation of MpS15 and NvS21 increased soybean grain, straw yield, and grain NPK contents. Interestingly, soil parameters (organic carbon, available NPK) showed a strong correlation (p < 0.05) with plant parameters and nutrient uptake. Overall, our study provides strong relationships between soil parameters, microbial inoculum as consortia, and soybean performance, and these strains may be utilized as bioinoculant in future.