Effect Of Bacterial Inoculation Research Articles

Phyto-treatment of tannery industry effluents under combined application of citric acid and chromium-reducing bacterial strain through Lemna minor L.: A lab scale study

Contamination of agricultural soils with heavy metals (HMs) poses a significant environmental threat, especially because industrial discharges often irrigate agricultural lands. A prominent source of HM(s) pollution occurs from tannery effluents containing high concentrations of chromium (Cr) in both Cr3+ and Cr6+ forms along with other toxic materials. Cr is known for its carcinogenic and mutagenic properties in biological systems. Microbe-assisted phytoremediation has emerged as a promising and environmentally friendly approach for detoxifying Cr-contaminated environments. This study aimed to evaluate the performance of citric acid (CA) and a Cr-reducing bacterial strain (Staphylococcus aureus) on the phytoextraction potential of Lemna minor within a Constructed Wetland System treated with tannery wastewater. Various combinations of tannery wastewater (0, 50, and 100 %), CA (0, 5 and 10 mM), and microbial inoculants were applied to the test plants. The mitigative effects of Staphylococcus aureus strain K1 were examined in combination with different concentrations of CA (0, 5, 10 mM). Data on growth and yield attributes highlighted the beneficial effects of bacterial inoculation and CA in ameliorating Cr toxicity in L. minor, as evidenced by increased foliar chlorophyll and carotenoid contents, enhanced antioxidant enzyme activities (SOD, POD, APX, CAT), and improved nutrient uptake. Specifically, CA application resulted in an enhancement of Cr ranging from 12% to 15% and 23%–31% in concentration, and 134%–141% and 322%–337% in Cr accumulation, respectively. When combined with the S. aureus inoculation treatment, CA application (5 and 10 mM) further increased the concentration and accumulation of Cr in L. minor. The enhancement in Cr ranged from 12% to 23% and 27%–41% in concentration, 68%–75%, and 179%–185% in accumulation, respectively. These results demonstrated that L. minor is an effective choice for environmentally friendly Cr remediation due to its continued ability to grow in polluted wastewater. This study suggested that microbial-assisted phytoextraction combined with chelating agents such as CA could be a practical and effective approach for remediating tannery effluents.

The Effects of Bacterial Inoculation on Agricultural and Quality Characteristics of Fenugreek (Trigonella foenum-graecum L.) Cultivars

The Effects of Bacterial Inoculation on Agricultural and Quality Characteristics of Fenugreek (Trigonella foenum-graecum L.) Cultivars

Plant Growth-Promoting Rhizobacteria: A Promising Strategy To Optimize The Development Of Schizolobium Parahyba

Objective: To investigate the efficacy of plant growth-promoting rhizobacteria (PGPR) in enhancing the early development stages of Schizolobium parahyba, a critical species for the timber industry, aiming to optimize reforestation and agroforestry practices for sustainable forestry. Theoretical Framework: The research is grounded in the exploration of symbiotic relationships between PGPR strains and plant species, focusing on their potential to improve seed germination, plant growth, and biomass production. The study examines how these interactions can be leveraged to enhance agricultural productivity and sustainability, with a specific emphasis on the benefits of employing PGPR in forestry. Method: The study utilized an experimental approach, assessing the impact of four PGPR strains (Serratia marcescens, Pseudomonas protegens, Enterobacter absuriae, and Acinetobacter calcoaceticus) on S. parahyba seedlings. These were cultivated in three different substrates, with variables such as germination rate, above-ground and root growth, and biomass production meticulously measured to evaluate the effects of bacterial inoculation. Results and Conclusions: The application of PGPR notably improved all measured growth parameters in S. parahyba seedlings, with A. calcoaceticus and P. protegens specifically enhancing stem and root development, respectively. A synergistic effect was observed in substrates containing peat, underscoring the significant potential of PGPR in boosting the productivity and sustainability of early-stage forestry cultivation. The findings advocate for further field studies to fine-tune these interactions, aiming to establish more resilient and ecologically sustainable agricultural practices. Originality/Value: This research contributes novel insights into the utilization of PGPR in forestry, highlighting its substantial promise in enhancing the early growth stages of Schizolobium parahyba. By demonstrating the specific benefits of PGPR strains and their interactions with different substrates, the study offers a promising strategy for improving the sustainability and productivity of reforestation and agroforestry efforts.

Bacterial inoculants and enzymes based silage cocktails boost the ensiling quality of biomasses from reed, corn and rice straw

This study investigated the effects of bacterial inoculants and enzyme-based silage cocktails on the dynamics of fermentation, microbiome, and nutritional value of silages produced from low-quality biomasses of reed, rice, and corn straw. A 90-day ensiling trial was performed using five distinct combinations of six basal bacterial species (Lactobacillus plantarum, Lactobacillus buchneri, Pediococcus pentosaceus, Aspergillus niger, Bacillus subtilis, and Candida utilis) and three basal enzymes (xylanase, β-mannanase, and glucanase). Each type of biomass was ensiled with six different treatments, including the Control treatment without an ensiling agent, the basal silage cocktail treatment (Mesa), and Mesa with a double dose of A. niger (MesaA), B. subtilis (MesaB), C. utilis (MesaC) and glucanase (MesaG). The “Mesa” contained (per kg silage), 1.0 × 106 CFU of L. plantarum, 1.4 × 107 CFU L. buchneri, 3.0 × 105 CFU P. pentosaceus, 8.0 × 108 CFU A. niger, 1.6 × 106 CFU B. subtilis and 1.0 × 109 CFU C. utilis, three enzymes (5.0 × 104 U xylanase, 2.5 × 103 U β-mannanase, and 1.0 × 104 U glucanase), and 20 mL molasses. Addition of the silage cocktails significantly improved the fermentation and nutritional quality of the reed, corn, and rice straw silages. Notably, the silage cocktails increased (P < 0.01) the contents of crude protein (CP), ether extract (EE), gross energy (GE), lactic acid (LA), ratio of LA to total acids and ensiling comprehensive evaluation scores, and decreased (P < 0.01) the contents of neutral detergent fiber (NDF), acid detergent fiber (ADF) and pH of reed, corn, and rice straw silages. Regarding the silage microbiome, silage cocktails decreased the relative abundance of Enterobacter and Rahnella1, and increased the relative abundance of Leuconostoc. A. niger, and B. subtilis had a strong positive correlation with CP, EE, GE and Lactobacillus, and a negative correlation with pH, Rhizobium, and Rahnella1 in reed, corn and rice straw silages. In comparison, C. utilis had a strong positive correlation with EE, and a negative correlation with pH, Rhizobium, Stenotrophomonas, and Rahnella1. Glucanase was positively correlated with LA, EE and GE, and negatively correlated with pH and Rahnella1. Silage quality characteristics and microbiome did not differ (P > 0.05) due to the composition of silage cocktails. Based on the comprehensive membership function analysis, the silage comprehensive evaluation scores were highest for double doses of B. subtilis and glucanase for reed, corn, and rice straw. This study revealed that silage cocktails upgraded straw silage fermentation and nutritional quality, and provided a practical solution for the optimal utilization of low-quality straw biomass.Graphical

Growth of Endophytic Bacteria from Klutuk Banana Plant (Musa balbisiana Colla) with Inoculation Trial on Rice Plants (Oryza sativa)

Four potential bacteria have been isolated from Klutuk banana plant. They exhibited IAA production. Since the bacterial inoculation to plant should be performed in exponential phase of bacterial growth, information of the growth is crucial. This study aimed to analyze the growth rate of eight isolates and examine the effect of bacterial inoculation by initial trial on rice plants. For this purpose, four endophytic bacteria from Klutuk banana were cultured and examined using 600nm spectrophotometer. The growth of the isolates was calculated every two hours for 16 hours bacterial growth in the nutrient broth medium. The inoculation trial of bacteria to rice plants was conducted with three replicates. This inoculation was begun by germinating the rice seed and the radicle was observed. Then, the germinated rice seedlings were soaked in the bacterial suspension for 5 minutes in room temperature. The results showed that the exponential phase of all isolates was observed 6 hours after shaking. Inoculation using 6-hour-incubated K7 isolate significantly improved the length of root of rice plants. Additionally, this isolate improved the number of root and shoot length without significant difference. Thus, these results provide important information of the growth phase and inoculation effect new isolated endophytic and rhizosphere bacteria.

Dual RNA-seq of maize and H. seropedicae ZAE94 association, in different doses of nitrate, reveals novel insights into Plant-PGPB-environment relationship.

The interactions between plants, beneficial bacteria and their environment are profoundly shaped by various environmental factors, including light, temperature, water availability, and soil quality. Despite efforts to elucidate the molecular mechanisms involved in the association between plants and beneficial bacteria, like Plant Growth-Promoting Bacteria (PGPB), with many studies focusing on the transcriptional reprogramming in the plant, there is no report on the modulation of genetic controls from both plant and associated bacteria standpoints, in response to environment. The main goal of this study was to investigate the relationship between plant-bacteria-environment signaling, using as a model maize plants inoculated with H. seropedicae ZAE94 and cultivated with different doses of N (0.3 and 3 mM). For this purpose, we performed rRNA-depleted RNA-seq to determine the global gene expression of both maize roots and associated H. seropedicae ZAE94. Our results revealed a differential modulation of maize nitrogen metabolism, phytohormone and cell wall responses when associated with H. seropedicae ZAE94 at different N concentrations. In parallel, a modulation of the bacterial metabolism could be observed, by regulating genes involved in transport, secretion system, cell mobility, oxidoreductases, and chemotaxis, when bacteria were associated with maize roots and cultivated at different doses of N. The molecular and phenotypic data of maize plantlets suggested that different doses of N fertilization differentially regulated the beneficial effects of bacterial inoculation, as higher doses (3 mM) favored shoot elongation and lower doses (0.3 mM) favored increase in plant biomass. Our results provide a valuable integrated overview of differentially expressed genes in both maize and associated H. seropedicae ZAE94 in response to different N availability, revealing new insights into pathways involved in grass-PGPB associations.

Application Effects of Bacterial Inoculants Producing Chitinase on Corn Silage

Application Effects of Bacterial Inoculants Producing Chitinase on Corn Silage

The use of Lentilactobacillus buchneri PJB1 and Lactiplantibacillus plantarum MTD1 on the ensiling of whole-plant corn silage, snaplage, and high-moisture corn

Experiments were conducted over a 3-yr period to evaluate the effects of bacterial inoculants on the fermentation profile and aerobic stability of whole-plant corn silage (WPC), snaplage (SNA), and high-moisture corn (HMC). Whole-plant corn was inoculated with Lentilactobacillus buchneri PJB1 in combination with Lactiplantibacillus plantarum MTD1 or with Lpb. plantarum alone (experiments 1 and 2). Snaplage (experiment 3) and HMC (experiments 4 and 5) were inoculated with Len. buchneri in combination with Lpb. plantarum or with Len. buchneri alone. After inoculation, the feedstuffs were ensiled in 7.57-L silos and stored at 21 ± 2°C for 30 or 90 d. In experiment 5, silage was subjected to air stress for 2 h every 2 wk through 42 d and then for 2 h/wk until 90 d and had samples analyzed for their bacterial community composition by metagenomics. Overall, in all experiments, silages inoculated with Len. buchneri alone or in combination with Lpb. plantarum had more acetic acid and 1,2-propanediol and fewer yeasts than uninoculated silages. After 30 d of ensiling, inoculation with Len. buchneri alone or in combination with Lpb. plantarum did not affect the aerobic stability of SNA, but it slightly increased the stability of WPC and markedly improved the stability of HMC. After 90 d of ensiling, inoculation with Len. buchneri alone or in combination with Lpb. plantarum markedly improved the aerobic stability of WPC, SNA, and HMC. In experiment 5, inoculation increased the relative abundance (RA) of Lactobacillaceae and reduced the RA of Enterobacteriaceae and Leuconostocaceae in HMC at 30 and 90 d and the RA of Clostridiaceae in non-air-stressed HMC at 90 d. Air-stressed HMC inoculated with Len. buchneri had less lactic acid, more acetic acid and 1,2-propanediol, and markedly greater aerobic stability than uninoculated air-stressed HMC at 90 d. In conclusion, inoculation with Len. buchneri PJB1 alone or in combination with Lpb. plantarum MTD1 increased the production of acetic acid and 1,2-propanediol, inhibited yeasts development, and improved the aerobic stability of WPC, SNA, and HMC. In HMC, inoculation markedly improved aerobic stability as soon as after 30 d of ensiling, and after 90 d, inoculation improved stability even under air stress conditions.

Effect of Non-Native Endophytic Bacteria on Oat (Avena sativa L.) Growth

Endophytic bacteria are known to influence vital activities of host plants. Endophytes can promote plant growth and provide a defense response against pathogens. The use of endophytes in crop production has the potential to reduce the application of fertilizer and pesticide input and thus improve the sustainability of crop production. In this study, we investigated the effects of seed inoculation with non-native endophytic bacteria, harvested from Brassica carinata, on oat (Avena sativa L.) growth with root vigor assays and greenhouse experiments. For root vigor assay experiments, seeds of two different oat cultivars were treated with 16 endophytic bacteria previously shown to promote growth benefits on multiple crop species. For the greenhouse experiments, the effect of seed inoculation with bacterial isolates was evaluated on ten oat cultivars at two fertilization levels. The root vigor assay showed that multiple isolates, including Bacillus licheniformis, Enterobacter kobei, B. halotolerans, B. cereus, B. aryabhattai, and Lysinibacillus fusiformis, had a positive effect on seedling root growth in one of the two oat cultivars. In the other cultivar, the bacterial isolates had either no effect or a negative effect on root growth. Greenhouse studies showed that the magnitude and direction of the effect of bacterial inoculation on oat growth varied with fertilization levels, bacterial strain, and oat cultivar. However, we identified two cultivars that were more responsive to bacterial inoculation than the others and for which bacterial inoculation of seed resulted in enhanced growth in several traits under both reduced and full nitrogen levels, and this response was observed for the two isolates tested. Our results show that inoculating oat seeds with non-native bacterial endophytes can promote root and shoot growth in oats. Developing biofertilizers that are effective across crop species, crop cultivars, and environmental conditions may be possible if cultivars are selected for their responsiveness across multiple bacterial isolates and in multiple growing environments. Overall, this study indicates that non-native endophytes could be considered for the development of biofertilizers with effectiveness across crop species.

Effects of bacterial inoculation on lignocellulose degradation and microbial properties during cow dung composting

ABSTRACTInoculation with exogenous microbial agents is a common method to promote organic waste degradation and improve the quality of compost. However, the biotic effects of different microbial agents are often quite different. To evaluate the potential effects of a complex bacterial agent comprised of three strains (belonging to Bacillus and Geobacillus) on lignocellulose degradation and the underlying microbial mechanisms during cow dung composting, two lab-scale composting experiments, a control and a bacterial inoculation treatment, were established. The results suggest that bacterial inoculation accelerated the rate of temperature increase and extended the thermophilic phase. Compared to those in the negative control group, cellulose, hemicellulose, and lignin degradation rates in the inoculated group increased from 53.3% to 70.0%, 50.2% to 61.3%, and 46.4% to 60.0%, respectively. The microbial community structure and diversity in the compost were clearly changed by the bacterial inoculation. Moreover, stamp analysis showed that inoculation modulated the key compost microbial functional populations linked to the degradation of lignocellulose. Correlation matrix analysis indicated that the expression of bacterial lignocellulolytic enzymes is closely related to key microbial functional populations. Overall, the results confirm the importance of bacterial inoculation, and have important implications for promoting the efficiency and quality of cow dung compost.

Effect of bacterial inoculants and their combination with enzymes and chemical additives on fermentation characteristics and ensiling period of maize silage

The study aimed to investigate effect of bacterial inoculants and their combinations with exogenous enzymes and chemical additives on the fermentation characteristics of maize silage at various ensiling periods. Five treatments were prepared viz., bacterial inoculant Lactobacillus plantarum (LP) and Lactobacillus fermentum (LF) (control), combination of LP+LF with xylanase enzyme (X), combination of LP+LF with cellulase enzyme (C), combination of LP+LF with X+C and combination of LP+LF with propionic acid (PA). Among the treatments, LP+LF+X+C additive treated silage had minimum dry matter loss throughout ensiling period. There was no significant difference in pH between LP+LF+X+C and LP+LF+X treated silage, but numerically pH value was lower in LP+LF+X+C treated silage. Lactic acid content significantly declined as ensiling period progresses but there was no significant difference among LP+LF+X+C, LP+LF+X treated silage and 15th, 25th days of ensiling. Lactic acid to acetic acid ratio was significantly improved in LP+LF+X+C treated silage as compared to other treatment combinations. The microbial count of silage was increased up to the 15th day of ensiling. This study concluded that desirable pH, lactic acid and flieg point required for good quality silage could be achieved on 15th day of ensiling in silages treated with LP+LF+X+C and LP+LF+X additive combination.

Inoculation reduces nitrate accumulation and increases growth and nutrient accumulation in hydroponic arugula

Inoculation with plant growth-promoting bacteria (PGPBs) has remarkably increased yield and nutrient uptake of crop plants. The objective of this study was to evaluate the effect of bacterial inoculation with Azospirillum brasilense, Bacillus subtilis and Pseudomonas fluorescens on growth, accumulation of nutrients as well as NNH4+ and NNO3− in hydroponic arugula plants. The research was carried out in a nutrient film technique (NFT) system and designed in randomized blocks with 5 replications. The treatments consisted of inoculation with A. brasilense, B. subtilis and P. fluorescens via nutrient solution at a dose of 0.1 mL L−1 and without inoculation treatment. Inoculation with P. fluorescens promoted NNH4+ accumulation in shoots and roots by 311% and 119% respectively as compared to non-inoculated plants. Inoculations with A. brasilense, B. subtilis and P. fluorescens reduced NNO3− accumulation in shoots and roots by18 and 14% as compared to without inoculation treatments. Fresh and dry mass of roots, root volume and leaf chlorophyll index were increased with inoculation of P. fluorescens and being considered the most suitable inoculant for hydroponic arugula cultivation. Inoculation with A. brasilense, P. fluorescens and B. subtilis reduced shoot NNO3− accumulation, thus benefiting human health.

Effect of Nitrogen Fertilization and Inoculation with Bradyrhizobium japonicum on Nodulation and Yielding of Soybean

Legumes’ nutrition relies on two sources of nitrogen (N): mineral N from soil, and biological N fixation (BNF). The aim of this study was to verify the effect of bacterial inoculation, as well as to compare it with the effect of different mineral N fertilization on the main nodulation characteristics, yield components and seed yield of two soybean (Glycine max (L.) Merr.) cultivars in the conditions of south-eastern Poland. A randomized block design was used with four replications and combining the application rates of mineral N (0, 30 and 60 kg·ha−1), and seed inoculation with Bradyrhizobium japonicum (HiStick® Soy and Nitragina) were applied for two soybean cultivars (Aldana, Annushka). It has been shown that inoculation of B. japonicum increases the nodulation on plant roots, yield components and seed yield, but no significant effect of the bacterial preparation used on the seed yield was observed. The application of 30 kg N·ha−1 did not result in a significant reduction in the number and weight of nodules, including on the main root and lateral roots, compared to seeds inoculated and not fertilized with N, as observed under a dose of 60 kg N·ha−1, but resulted in an increase in the number of pods and the number and weight of seeds per plant. For both soybean cultivars, the best combination was nitrogen fertilization at 30 kg N·ha−1 and seed inoculation with B. japonicum, regardless of the bacterial preparation used.

Integrated application of phosphorus-accumulating bacteria and phosphorus-solubilizing bacteria to achieve sustainable phosphorus management in saline soils

The challenge of managing agricultural phosphorus (P) in saline regions entails both reducing leaching for environmental protection and maintaining soil available P levels for crop production, which could be achieved through functional microorganisms that can facilitate P transformation processes like P assimilation, inorganic P solubilization, and organic P mineralization. In this study, we proposed an integrated utilization of phosphorus-accumulating bacteria (PAB) and phosphorus-solubilizing bacteria (PSB) to reach the goal of alleviating P leaching while improving soil available P levels. The study conducted a microcosm experiment that combined a soil column test, soil incubation, and pot experiment to evaluate the effect of bacterial inoculants on soil P leaching, soil P availability, and plant P accumulation. The results showed that the application of PAB reduced 22.6 % of dissolved P leaching through the absorption of labile phosphate in the soil, and 17.3 % of particulate P leaching through the promoted soil aggregation. The integrated inoculation of PSB and PAB synergistically improved soil available P content by 18.3 % through the mineralization of soil organic P, and remarkably boosted wheat growth and its P accumulation. Microbial community analysis revealed that the integrated microbial treatment decreased the diversity of soil bacterial community and increased the abundance of native microbial species, i.g. Lysobacter and Ramlibacter, which were positively correlated with soil available P content and alkaline phosphatase level. In conclusion, the integrated microbial strategy based on halotolerant PAB and PSB has great potential for sustainable P management in saline areas and agricultural activities.

Bacterial inoculation of Quercus pyrenaica trees alters co-occurrence patterns but not the composition of the rhizosphere bacteriome in wild conditions.

Quercus pyrenaica is a woody species of high landscape value, however, its forests show an advanced state of degradation in the Iberian Peninsula. Afforestation typically has low success, thus, it is necessary to improve the fitness of oaks plantlets to be transplanted, for instance, by inoculating beneficial microorganisms. In adding microorganisms to ecosystems, there must be balanced efficacy with potential effects on native microbial communities. We addressed changes in diversity, richness, composition and co-occurrence networks of prokaryotic communities in the rhizosphere of inoculated and control trees outplanted to three different sites located in the Sierra Nevada National and Natural Park (Spain). After 18 months in wild conditions, we did not detect changes due to the inoculation in the richness, diversity and structure in none of the sites. However, we observed an increase in the complexity of the co-occurrence networks in two experimental areas. Modularization of the networks changed as a result of the inoculation, although the sense of the change depended on the site. Although it was impossible to unravel the effect of bacterial inoculation, our results highlighted that inoculation alters the association of rhizosphere bacteria without entailing other changes, so networks should be analysed prior to inoculating the plantlets.

Effect of Bacterial Inoculation and Foliar Application of Arginine and Glutamic Acids on the Growth of Fenugreek Plant (Trigonella foenum-graecum L.)

A field experiment was conducted during the winter seasons 2020-2021 and 2021-2022 in Haditha district, Barwana district, which is located in the northwestern part of the center of Anbar province and is characterized by its sandy, clay soil. In order to study the effect of bacterial inoculation and spraying with arginine and glutamic acids on the physiological traits of fenugreek (Trigonella foenum-graecum L). The experiment included (18) treatments resulting from the interaction of the bacterial bio-inoculation (Sinorhizobium meliloti) (inoculated and without inoculated ) with combinations of amino acids arginine and glutamic. The experiment was designed according to RCBD with a within the split plots. The results of the study showed a superiority of the inoculation treatment with (Sinorhizobium meliloti) in the traits of root growth. Also in the traits of vegetative growth. The combination of arginine 50 mg.L-1 + glutamic 50 mg.L-1 was significantly excelled in root growth traits. As well as in the traits of vegetative growth.

Coinoculação com Bradyrhizobium ssp. e Azospirillum brasilense em feijão caupi sob estresse salino

ABSTRACT Plants grown under salinity are subject to many morphological and physiological disorders. In this context, practices that can enable the use of saline water are essential. The deleterious effects of salinity can be mitigated by using beneficial microorganisms, especially diazotrophic bacteria. In this context, this study aimed to evaluate the effect of bacterial inoculation and co-inoculation using Bradyrhizobium spp. and Azospirillum brasilense on the growth, nodulation and production of cowpea under salt stress. The experiment was conducted using a randomized block design, in a 4 × 5 factorial arrangement, corresponding to four nitrogen sources (N1 - without nitrogen and without inoculant; N2 - fertilization with mineral nitrogen and without inoculant; N3 - inoculation of Bradyrhizobium spp.; and N4 - co-inoculation of Bradyrhizobium spp. and Azospirillum brasilense) and five values of electrical conductivity of irrigation water - ECw (0.4, 1.9, 3.4, 4.9 and 6.4 dS m-1), with five replicates. Co-inoculation with Azospirillum brasilense and Bradyrhizobium spp. favors the growth, production and nodulation of cowpea plants up to ECw of 0.4 dS m-1. Increase in the electrical conductivity of irrigation water negatively affects the growth, production and nodulation of cowpea plants in Corujinha variety, regardless of the nitrogen source used.

Localization and synthesis of lipid-transfer proteins in pea plants after treatment by strain of growth-stimulating bacteria and their role in the formation of Casparian bands and the regulation of hydraulic conductance

The presence of PGP bacteria in the rhizosphere has a positive effect on plant growth and increases their productivity both under favorable and stressful conditions. Despite the fact that much attention is paid to the various mechanisms of action of growth-promoting bacteria on plants, the aspect of the effect of bacteria on changes in the formation of apoplastic barriers and their effect on water transport remains almost unexplored. Previously, it was shown that Pseudomonas mandelii IB-Ki14 accelerated the formation of Casparian bands in wheat plants, although the involvement of LTPs (Lipid Transfer Proteins) in this process has not been shown. The aim of this study was to elucidate the effect of bacterial inoculation on LTP synthesis in the roots of the pea (Pisum sativum) and its relation to the formation of apoplastic barriers and hydraulic conductance. We aimed to test the hypothesis that the decrease in hydraulic conductance due to increased formation of apoplastic barriers can be compensated by increased activity of aquaporin water channels. Activation of genes encoding PsLTP and an increase in the amount of lipid-transporting proteins in pea root phloem induced by P. mandelii IB-Ki14 treatment were found. Inoculation was accompanied by an increase in suberin deposition in the Casparian bands, while hydraulic conductivity did not decrease. The use of Fenton's reagent, which is an inhibitor of aquaporins, showed that the hydraulic conductivity of plants treated with bacteria decreased to a greater extent compared to the control group, which indicates an increase in the activity of aquaporins under the influence of bacteria. We conclude that P. mandelii IB-Ki14 stimulates the deposition of suberin, the biosynthesis of which involves lipid-transporting proteins, and increases the activity of aquaporins, which, in turn, prevents a possible decrease in hydraulic conductivity due to the formation of apoplastic barriers in pea roots.

Effect of seed biopriming with selected endophytes on the growth and chilling tolerance of rice plants.

The aim of this study was to develop an efficient bioinoculant for amelioration of adverse effects from chilling stress (10°C), which are frequently occurred during rice seedling stage. Seed germination bioassay under chilling condition with rice (Oryza sativa L.) cv. Tainan 11 was performed to screen for plant growth-promoting (PGP) bacteria among 41 chilling-tolerant rice endophytes. And several agronomic traits were used to evaluate the effects of bacterial inoculation on rice seedling, which were experienced for 7-d chilling stress in walk-in growth chamber. The field trials were further used to verify the performance of potential PGP endophytes on rice growth. A total of three endophytes with multiple PGP traits were obtained. It was demonstrated that Pseudomonas sp. CC-LS37 inoculation led to 18% increase of maximal efficiency of Photosystem II (PSII) after 7-d chilling stress and 7% increase of chlorophyll a content, and 64% decline of malondialdehyde content in shoot after 10-d recovery at normal temperature in walk-in growth chamber. In field trial, biopriming of seeds with strain CC-LS37 caused rice plants to increase shoot chlorophyll soil plant analysis development values (by 2.9% and 2.5%, respectively) and tiller number (both by 61%) under natural climate and chilling stress during the end of tillering stage, afterward 30% more grain yield was achieved. In conclusion, strain CC-LS37 exerted its function in increase of tiller number of chilling stress-treated rice seedlings via improvement of photosynthetic characteristics, which in turn increases the rice grain yield. This study also proposed multiple indices used in the screening of potential endophytes for conferring chilling tolerance of rice plants.

Effects of bacterial inoculants on the microbial community, mycotoxin contamination, and aerobic stability of corn silage infected in the field by toxigenic fungi

This study aimed to evaluate the effects of inoculants on the microbial community and mycotoxins contamination of corn silage during aerobic exposure. Whole-crop corn infected with or without mycotoxigenic fungi were ensiled with Lentilactobacillus buchneri (LB, 1.0 × 106 cfu/g fresh weight (FW)), Lactiplantibacillus plantarum (LP, 1.0 × 106 cfu/g FW), or LBLP at 1.0 × 106 cfu/g FW each. The concentration of acetic acid (AcA) (P < 0.05) in LB and LBLP silages was higher than in control (C) and LP of non-fungal infection (NFI) silages. The fungal infection resulted in a larger increase of zearalenone (ZEN, P = 0.01), fumonisin B1 (FUB1, P = 0.02), and fumonisin B2 (FUB2, P = 0.02). The relative abundance (RA) of Issatchenkia in NFI was higher (P < 0.001) than FI silages, whereas the RA of Kazachstania (P < 0.001), Zygosaccharomyces (P = 0.047), and Candida (P = 0.025) in NFI were lower than these of FI silages. The aerobic stability was improved by the application of LB and LBLP as compared with the C of NFI silages. The LB and LBLP had the potential to improve aerobic stability and alleviate mycotoxins contamination of non-fungal infected corn silages.Graphical