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Expanding eco-friendly approaches to improve plant growth and crop productivity is of great important for sustainable agriculture. Therefore, a field experiment was carried out at the Faculty of Agriculture Farm, Mansoura University, Egypt during the 2018 and 2019 growing seasons to study the effects of different bio- and organic fertilizers and their combination on hybrid maize growth, yield, and grain quality. Seeds were treated with Azotobacter chrocoocum, arbuscular mycorrhizal fungi (AMF), Bacillus circulans, biogas slurry, humic acid (HA), and their combination aiming to increase the growth and yield of maize and to reduce the need for chemical fertilizers. The results showed that combined application of the biofertilizer mixture (Azotobacter chrocoocum, AMF, and Bacillus circulans) with organic fertilizers enhanced maize growth, yield, and nutrient uptake. Moreover, the bio-organic fertilization has improved the soluble sugars, starch, carbohydrates, protein, and amino acid contents in maize seeds. Additionally, the bio-organic fertilization caused an obvious increase in the microbial activity by enhancing acid phosphatase and dehydrogenase enzymes, bacterial count, and mycorrhizal colonization levels in maize rhizosphere as compared with the chemical fertilization. Additionally, the bio-organic fertilizers has improved α-amylase and gibberellins (GA) activities and their transcript levels, as well as decreased the abscisic acid (ABA) level in the seeds as compared to the chemical fertilizers. The obtained results of bio-organic fertilization on the growth parameters and yield of maize recommend their use as an alternative tool to reduce chemical fertilizers.

It’s been long known that the application of organic fertilizer (OF) and bio-organic fertilizer (BF) which containing beneficial microorganisms to pear trees can both significantly improve fruit quality and yield. In order to reveal the mechanism of BF and OF regulating fruit growth and quality in pear, the effects of BF and OF on the photosynthetic characteristics and the accumulation of major sugars and organic acids of the pear fruit were quantified compared with chemical fertilizer (CF). Additionally, the molecular mechanisms regulating pear fruit development and quality were studied through transcriptome analysis. The three treatments were conducted based on the same amounts of nitrogen supply. The results showed that compared with CF, BF and OF treatments increased the fruit yield, and also significantly improved the photosynthesis efficiency in pear. BF and OF both significantly increased the sucrose content but significantly decreased the fructose and glucose content within the pear fruit. The amount of malic acid was significantly higher in OF treatment. Compared with CF and OF, BF significantly increased the sugar-acid ratio and thus improved the fruit quality. Transcriptome analysis and weighted correlation network analysis (WGCNA) revealed that the sugar metabolism of fruits applied with the BF was enhanced compared with those applied with CF or OF. More specifically, the expression of SDH (Sorbitol dehydrogenase) was higher in BF, which converts sorbitol into fructose. For both of the OF and BF, the transcript abundance of sugar transporter genes was significantly increased, such as SOT (Sorbitol transporter) , SUT14 (Sugar transport 14) , UDP-GLUT4 (UDP-glucose transporter 4) , UDP-SUT (UDP-sugar transporter), SUC4 (Sucrose transport 4), SUT7 (Sugar transporter 7), SWEET10 and SWEET15 (Bidirectional sugar transporter) , which ensures sugar transportation. The genes involved in organic acid metabolism showed decreased transcripts abundance in both BF and OF treatments, such as VAP (Vesicle-associated protein) and cyACO (Cytosolic aconitase) , which reduce the conversion from succinate to citric acid, and decrease the conversion from citric acid to malic acid in the TCA cycle (Tricarboxylic Acid cycle) through Pept6 (Oligopeptide transporter). In conclusion, the application of BF and OF improved fruit quality by regulating the expression of sugar and organic acid metabolism-related genes and thus altering the sugar acid metabolism. Both BF and OF promote sucrose accumulation and citric acid degradation in fruits, which may be an important reason for improving pear fruit quality. The possible mechanism of bio-organic fertilizer to improve fruit quality was discussed.

Fusarium wilt is one of the most serious diseases caused by a soil-borne pathogen affecting banana production. The goal of this study was to evaluate the capability of a novel bio-organic fertilizer (BIO2) that integrated the biocontrol agent Bacillus subtilis N11, and mature composts to control Fusarium wilt of banana in pot experiments. The results showed that the application of the BIO2 significantly decreased the incidence rate of Fusarium wilt compared to the control. To determine the antagonistic mechanism of the strain, we also studied the colonization of the natural biocontrol agent on banana roots using a GFP marker. The studies were performed in a hydroponic culture system, a sand system and a natural soil system. The results indicated that the bacteria colonized predominantly by forming biofilms along the elongation and differentiation zones of the roots. The fact that similar observations were obtained in all three systems suggests that colonization by N11 can be studied in a defined system. The population of B. subtilis N11 in the rhizosphere and on banana roots was also monitored. We speculate that the colonization pattern of B.subtilis N11 can be linked to the mechanism of protection of plants from fungal infection.

This study investigates the potential of leaf and various organic waste composts as bio-organic fertilizers using 16S rRNA metagenomics. The microbial richness and diversity analysis, employing alpha and beta diversity indices, reveal substantial variations influenced by organic substrates during composting. The leaf compost had a high total OTU (70,554) but low microbial diversity (Chao 1 index = 272.27). The kitchen waste compost had the highest microbial diversity (Chao 1 index = 429.18). Positive correlations between microbial biomass, diversity, and compost quality highlighted the pivotal role of microbial activity. The beneficial genera identified across all the bio-composts were Lactobacillus, Leuconostoc, Sphingobacterium, Paenibacillus, Pseudomonas, and Clostridium. Some pathogenic genera were also detected in all the composts analyzed, viz. Prevotella, Agrobacterium, Fusobacterium, and Streptococcus. Nonetheless, the ratio of beneficial to the pathogenic genera was generally high in all compost, highlighting the enrichment with beneficial microorganisms. The leaf compost demonstrated the highest proportion of beneficial genera, about 92%, indicating significant bio-fertilizing potential, with a low % level of pathogenic genera of about 3%. Thus, the leaf compost has excellent potential to be used as a bio-organic fertilizer. Understanding the microbial composition of organic waste composts is crucial for its application as bio-fertilizer for promoting sustainable agriculture.

Damping-off disease is caused by Rhizoctonia solani and leads to serious loss in many crops. Biological control is an efficient and environmentally friendly way to prevent damping-off disease. Optical micrographs, scanning electron micrographs, and the determination of hydrolytic enzymes were used to investigate the antagonism of Trichoderma harzianum SQR-T37 (SQR-T37) against R. solani. Experiments were performed in pots to assess the in vivo disease-control efficiency of SQR-T37 and bio-organic fertilizer. The results indicate that the mycoparasitism was the main mechanism accounting for the antagonistic activity of SQR-T37. In one experiment, the population of R. solani was decreased from 106 internal transcribed spacer (ITS) copies per gram soil to 104 ITS copies per gram soil by the presence of the antagonist. In this experiment, 45% of the control efficiency was obtained when 8 g of SQR-T37 hyphae per gram soil was applied. In a second experiment, as much as 81.82% of the control efficiency was obtained when bio-organic fertilizer (SQR-T37 fermented organic fertilizer, BIO) was applied compared to only 27.27% of the control efficiency when only 4 g of SQR-T37 hyphae per gram soil was applied. Twenty days after incubation, the population of T. harzianum was 4.12 × 107 ITS copies per gram soil in the BIO treatment, which was much higher than that in the previous treatment (8.77 × 105 ITS copies per gram soil), where only SQR-T37 was applied. The results indicated that SQR-T37 was a potent antagonist against R. solani in a mycoparasitic way that decreased the population of the pathogen. Applying BIO was more efficient than SQR-T37 application alone because it stabilized the population of the antagonist.

Aims Many Trichoderma species are well-known by their ability to promote plant growth and health. However, few studies have been conducted to improve their ability. Laboratory and greenhouse experiments compared the promotion of cucumber growth by the putative mutant Trichoderma harzianum T-E5 versus the wild-type SQR-T037 and bio-organic fertilizers fortified with them. Methods The putative mutant T-E5 was selected based on plant hormone production in liquid fermentation and then on the effects of T-E5 and SQR-T037 to promote plant growth and colonization of plant roots and rhizosphere soil of cucumber. Results High-performance liquid chromatography analysis showed that indole acetic acid (IAA) production by T-E5 was enhanced by 30.2 % as compared with SQRT037. T-E5 treatment statistically increased cucumber plant biomass in soil and hydroponic experiments. Based on TaqMan reverse transcriptase-polymerase chain reaction, the population of T-E5 was almost ten times higher than SQR-T037 in the soil samples at 30 days. The endophytic colonization of roots and stems by the two strains had the same dynamic tendency, but T-E5 was much greater than SQR-T037 at any sampling time. Conclusions The putative mutant T-E5 enhanced the production of IAA and plant colonization ability, and this improvement had a great potential for further application of T-E5 in crop production.

Background Plant diseases caused by fungal pathogen result in a substantial economic impact on the global food and fruit industry. Application of organic fertilizers supplemented with biocontrol microorganisms ( i.e. bioorganic fertilizers) has been shown to improve resistance against plant pathogens at least in part due to impacts on the structure and function of the resident soil microbiome. However, it remains unclear whether such improvements are driven by the specific action of microbial inoculants, microbial populations naturally resident to the organic fertilizer or the physical-chemical properties of the compost substrate. The aim of this study was to seek the ecological mechanisms involved in the disease suppressive activity of bio-organic fertilizers. Results To disentangle the mechanism of bio-organic fertilizer action, we conducted an experiment tracking Fusarium wilt disease of banana and changes in soil microbial communities over three growth seasons in response to the following four treatments: bio-organic fertilizer (containing Bacillus amyloliquefaciens W19), organic fertilizer, sterilized organic fertilizer and sterilized organic fertilizer supplemented with B . amyloliquefaciens W19. We found that sterilized bioorganic fertilizer to which Bacillus was re-inoculated provided a similar degree of disease suppression as the non-sterilized bioorganic fertilizer across cropping seasons. We further observed that disease suppression in these treatments is linked to impacts on the resident soil microbial communities, specifically by leading to increases in specific Pseudomonas spp.. Observed correlations between Bacillus amendment and indigenous Pseudomonas spp. that might underlie pathogen suppression were further studied in laboratory and pot experiments. These studies revealed that specific bacterial taxa synergistically increase biofilm formation and likely acted as a plant-beneficial consortium against the pathogen. Conclusion Together we demonstrate that the action of bioorganic fertilizer is a product of the biocontrol inoculum within the organic amendment and its impact on the resident soil microbiome. This knowledge should help in the design of more efficient biofertilizers designed to promote soil function. D1PtKTqtmixUWuvNc217Qu Video Abstract

There were some errors in section2 Materials and methods, 2.4 Bioinformatics and data statistical analysis, Paragraphs 2 and 3. Permutational multivariate analysis of variance (PERMANOVA) was conducted using the “adonis” function in R’s vegan package (version 4.5.1) to determine significant differences in microbial community composition. A correction has been made to the section: “Depending on the experimental design, ANOVA after checking the homoscedasticity or independent sample t-tests were used to evaluate treatment effects, with the significance P < 0.05.

AimsFor the sustainable development of agroecosystems in citrus orchards, we studied the short-term effects of bio-organic fertilizer substitution for chemical fertilizers on the dynamic changes in the soil environment.MethodsWe carried out a field experiment in citrus orchards. Five treatments were set up with a duration of six months and the substitution ratio was based on equivalent nitrogen substitution. Soil properties, soil labile organic carbon, and soil bacteria were measured and analyzed.ResultsBio-organic fertilizers substituting chemical fertilizers could significantly increase soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), dissolved organic carbon (DOC), and easily oxidized organic carbon (EOC) content (P < 0.05). The carbon pool management index (CPMI) was the largest in 75% bio-organic fertilizer treatment. In addition, the substitution of chemical fertilizers with bio-organic fertilizers significantly increased the alpha diversity of bacterial communities, with a maximum Shannon index of 9.78 for SF75. The relative abundance of Actinobacteria, Actinobacteria and Bacteroidetes was higher than that of CK, while the relative abundance of Acidobacteria and Choloflexi was lower than that of the control group. Redundancy analysis showed that DOC, CPMI, available potassium (AK), and nitrate-nitrogen (NO3−-N) were the main driving factors affecting the bacterial community structure. The highest expression abundance of metabolic pathways in soil bacteria was predicted by KEGG to exist.ConclusionWe conclude that the appropriate application of bio-organic fertilizer improved soil properties and reshaped bacterial ecology and 75% bio-organic fertilizer is a promising fertilization practice for citrus orchard soils.

Chemical fertilizer has been excessively used for high yield of citrus around the world, especially in China; meanwhile, it deteriorates the citrus orchard soil environment. To resolve the conflict, the use of organic fertilizer provides a promising solution. However, the data about organic fertilizer used in citrus orchard is rarely available. Here, four treatments including CK (no fertilizer), CF (chemical fertilizer), OF + CF (chemical fertilizer reduction combined with organic fertilizer; application of N, P2O5, K2O fertilizer and organic fertilizer is 0.564, 0.236, 0.336 and 10 kg/plant), and BF + CF (chemical fertilizer reduction combined with bioorganic fertilizer; application of N, P2O5, K2O fertilizer and bioorganic fertilizer is 0.508, 0.320, 0.310 and 10 kg/plant) were performed in a ‘Ponkan’ (Citrus reticulata Blanco) orchard to evaluate the effect of organic fertilizer on citrus yield, growth, soil properties etc. when nutrients of fertilizer of each treatment were equal except CK. The data obtained in 2019 and 2020 showed that both OF + CF and BF + CF were beneficial to improve soil fertility (soil physicochemical and microbe properties) and citrus growth physiology (growth, nutrient and photosynthesis), alleviate NO3−-N leaching, and promote yields. Comprehensive evaluation indicated that BF + CF was more effective than OF + CF. Together, organic fertilizer has the potential to substitute partial chemical fertilizer with improvement in soil properties, growth physiology, and yield of citrus.