Root-knot nematodes (RKN) cause extensive damage to grapevine cultivars. RKN-resistant grapevine rootstocks remain vulnerable to biotic and abiotic stresses. This study aimed to determine the influence of composted animal manures (CAMs) [chicken manure (CM), cow manure (CowM), and sheep manure (SM)] with or without plant growth-promoting rhizobacteria (PGPR) on the population of Meloidogyne incognita, free-living nematodes (FLNs) and predaceous nematodes (PNs) residing in the soils of vineyard cultivars (Flame, Superior and Prime). The nematodes were isolated from grapevine roots and rhizosphere soils, then the absolute frequency of occurrence (FO), relative FO, prominence value (PV), and population density (PD) were assessed. The impact of CAMs and PGPR on the growth parameters, fruit output, and quality of three grapevine varieties was subsequently evaluated. Eight treatments included a control without CAMs or PGPR amendments, the CAMs alone, or CAM treatments combined with PGPR. The results showed that FLNs and PNs were more abundant in Prime than Flame or Superior cultivars when poor sandy loam soils were supplied with CAMs. Among all tested manures, CM was the best treatment as a nematicide. This was evident from the decreased numbers of M. incognita and increased numbers of FLNs and PNs in grapevine fields. Compared to the soil-applied oxamyl (a systemic nematicide), which was efficiently suppressive on M. incognita for two months, CM significantly (P < 0.05) decreased PD of the phytonematodes for five months, improved soil structure and enhanced the soil biological activities. There were significant (P < 0.05) increases in the number of leaves/vines by 79.9, 78.8, and 73.1%; and total fruit weight/vine by 76.9, 75.0, and 73.0% in Flame, Superior, and Prime varieties, respectively, compared to untreated vines. Regardless of the cultivar, soils amended with CM + PGPR achieved the lowest number of M. incognita among all other treatments, followed by SM + PGPR and CowM + PGPR. It was concluded that CAMs amendment, mainly CM, along with PGPR in poor sandy soils of temperate areas, is considered a sustainable approach for reducing parasitic nematodes and improving agricultural management.

AimsPecan (Carya cathayensis Sarg.) is an important forest trees in China, the application of chemical pesticides for disease control has caused severe damage to the soil, including reduced fertility and disruption of microbial communities. Although Trichoderma treatment has been shown to promote plant growth and improve soil quality, its effects on the growth promotion of pecan and the impact on soil microbial communities and physicochemical properties remained unclear.MethodsIn this study, we investigated the impact of T. asperellum TCS007 spore suspension and its fermented crude extract on the growth and development of pecan seedlings. We also explored the effects of TCS007 treatment on the nutrients, enzyme activities, and microbial diversity in the rhizosphere soil of pecan seedlings during their three main growth stages.ResultsTreatment with TCS007 spore suspension or crude extract promoted the growth of pecan seedlings, with significantly higher levels of leaf hormones and defense enzyme activity compared to the control (CK). Moreover, the content of soil organic matter and ammonium nitrogen, as well as the activity of soil enzymes such as catalase and urease, were all significantly higher than CK after treatment, and the soil pH shifted from slightly acidic to slightly alkaline. The results indicated that TCS007 treatment significantly increased the richness of beneficial fungi and bacteria in the soil.ConclusionThe results demonstrated that TCS007 treatment significantly promoted the growth of pecan plants, increased enzyme activity and nutrient content in the soil, and improved the soil micro-ecological environment.

Highly saline soils negatively affect crop growth, especially rice. Although chemical approaches can be used, they damage the environment and the sustainability of the agriculture. Thus, a biological candidate should be assessed. Therefore, the study evaluated the impact of nitrogen (N)-fixing purple non-sulfur bacteria (PNSB) strains on improving soil properties, nutrient uptake, growth, and rice yield on highly saline soil in My Xuyen district, Soc Trang province. The N-fixing PNSB were hypothesized to boost soil nutrient availability and reduce soil salinity, leading to a greater rice growth and yield. A pot experiment was arranged in a completely randomized block design with two factors, including four N applying rates (100, 75, 50, and 0%) and N-fixing PNSB Rhodobacter sphaeroides (no added bacteria, single bacterial strain R. sphaeroides S01, single bacterial strain R. sphaeroides S06, and a mixture of two bacterial strains R. sphaeroides S01 and S06). The results showed that adding single strains S01, S06, and mixed strains S01 and S06 improved plant height by 4.02-10.4% (the first season) and 3.86-6.84% (the second season). Under the application of the mixture of two strains S01 and S06, the soil NH4 + increased by 31.8-50.5%, while the soil Na+ decreased by 16.0-25.7% in both seasons. From there, the total N uptake was also improved by 34.9-73.8% and the total Na uptake went down by 19.1-26.5% via two seasons. This led to greater rice growth and yield traits, such as the number of panicles per pot, the number of seeds per panicle, and the filled seed rate in both seasons. Ultimately, the rice grain yield was improved by 10.2-14.8% by the N-fixing PNSB under greenhouse condition. In conclusion, the current study successfully provided a potent N-fixer as a candidate for improvements of saline rice growth and soil health. Thus, this liquid biofertilizer should be further tested under field trails.

Background and aims Nursery and field growth of micro-propagated banana plantlets is influenced by pests, nutrients and substrate quality. This study aims to evaluate the potential of locally produced microbial inoculant to reduce nematode and borer weevil (Cosmopolites sordidus) pest effects on micro-propagated banana plantlets and stimulate growth. Methods The potential of locally produced microbial inoculant to reduce nematode and borer weevil pest effects on micro-propagated banana plantlets and stimulate growth was tested in nursery and field conditions. Plantlets were grown in polybags with three substrates (Soil + Coffee husk, Soil + Cocoa pod, and Soil + Empty palm fruit bunch) and two nutrient sources (chemical NPK fertilizer and microbial inoculant) relative to untreated control. Results Significant (P < 0.05) root necrosis occurred following nematode inoculation with/without borer weevil at planting or ten weeks after, with lower necrosis in pesticide and microbial inoculant than untreated control. Similarly, significant (P < 0.01) corm damage occurred following borer weevil inoculation with/without nematode at planting or ten weeks after, with lower corm damage in pesticide and microbial inoculant than untreated control. Although similar nursery growth of micro-propagated banana plantlets was observed across substrates, significant (P < 0.05) variation occurred between nutrient sources, with higher growth for NPK and microbial inoculant than untreated control. Similarly, field growth of banana plantlets was higher for NPK and microbial inoculant than untreated control (P < 0.05). Conclusion These findings open up avenues for further investigation on role of locally produced microbial inoculant as promising option to reduce effects of nematode and borer weevil pests on micro-propagated banana plantlets and stimulate growth.

The application of phosphate-solubilizing microbes (PSMs) as biofertilizers in agricultural systems has not satisfactorily solved the problem of reducing our reliance on chemical phosphorus (P) fertilizers. Ongoing efforts are continually trying to translate promising laboratory results to successful deployment under field conditions, which are typically met with failure. In this review, we summarize the state-of-the-art research on PSMs and their role in the terrestrial P cycle, including previously overlooked molecular and cellular mechanisms underpinning phosphate solubilization. PSMs capable of transforming either organic or complexed inorganic P compounds are discussed. By providing environmentally secure and environmentally friendly ways to increase the accessibility of phosphate, these bacteria effectively transform insoluble phosphate molecules into forms that plants can utilize, encouraging crop growth and increasing nutrient usage effectiveness. The use of PSMs in agriculture sustainably improves crop productivity and has enormous potential for tackling issues with global food security, reducing environmental damage, and promoting sustainable and resilient agricultural systems. Furthermore, due to resource shortages, the changing global climate and need to reduce environmental risks associated with the overuse of chemical phosphate fertilizer, PSMs have the potential to be sustainable biofertilizer alternatives in the agricultural sector. Phosphate-solubilizing microorganisms constitute a cutting-edge field in agriculture and environmental science. In addition, this paper elaborates on the groups and diversity of microbes hitherto identified in phosphate solubilization. Also, factors that had hitherto hindered the reproducibility of lab results in field settings are succinctly highlighted. Furthermore, this paper outlines some biofertilizer formulations and current techniques of inoculation according to the test crop/strain. Finally, laboratory, greenhouse, and field results are presented to acquaint us with the current status of the use of PSM-based biofertilizers.

Using chemical fertilizers in agriculture increases production and improves the quality of the product; however, their higher usage globally has brought forth damage to ecosystems. Using biofertilizers is a better strategy to reduce the use of chemical fertilizers and ultimately increase soil fertility. This study aimed to isolate, identify, and characterize bacteria from the soil rhizosphere of medicinal plants ( Rumex tuberosus L. and Verbascum sp.) for in vivo screening. Nitrogen fixation, phosphate solubilization, HCN, ammonia levels, Lipase, protease, catalase and siderophore production biochemical tests were also conducted. The two isolates that gave positive results from the biochemical tests were chosen out of 25 for further experiments. Based on 16S rRNA sequencing analysis the isolated organisms were identified as Alcaligenes faecalis Go1 (Accession No. OP001725) and Bacillus subtilis T11 (Accession No. OP218376). The compound fertilizer NPK was used as the positive control for field experiments, while selected stains were individually and in-combination were tested on potato crops as inoculum, over two successive cropping seasons. Plant height, number of tubers per plant, chlorophyll content, and tuber weight all increased for both isolated bacterial strains. The quality of the potato tubers was checked through visual observation for the presence or absence of disease symptoms. The treated tubers exhibited excellent quality, remaining free from any signs of disease, however, the control tubers showed infections with ( Streptomyces scabiei, Fusarium sp ., F. solani and Erwinia amylovora). The soil analyzed after harvesting both bacteria increased percentages of P, Ca2+, Mg2+, Na+, K+, SO4, total nitrogen content and total organic matter. The findings showed that the tested bacterial isolates could replace the use of chemical fertilizers in the production of potatoes.

For the safe use of microbiome-based solutions in agriculture, the genome sequencing of strains composing the inoculum is mandatory to avoid the spread of virulence and multidrug resistance genes carried by them through horizontal gene transfer to other bacteria in the environment. Moreover, the annotated genomes can enable the design of specific primers to trace the inoculum into the soil and provide insights into the molecular and genetic mechanisms of plant growth promotion and biocontrol activity. In the present work, the genome sequences of some members of beneficial microbial consortia that have previously been tested in greenhouse and field trials as promising biofertilizers for maize, tomato and wheat crops have been determined. Strains belong to well-known plant-growth-promoting bacterial genera such as Bacillus, Burkholderia, Pseudomonas and Rahnella. The genome size of strains ranged from 4.5 to 7.5 Mbp, carrying many genes spanning from 4402 to 6697, and a GC content of 0.04% to 3.3%. The annotation of the genomes revealed the presence of genes that are implicated in functions related to antagonism, pathogenesis and other secondary metabolites possibly involved in plant growth promotion and gene clusters for protection against oxidative damage, confirming the plant-growth-promoting (PGP) activity of selected strains. All the target genomes were found to possess at least 3000 different PGP traits, belonging to the categories of nitrogen acquisition, colonization for plant-derived substrate usage, quorum sensing response for biofilm formation and, to a lesser extent, bacterial fitness and root colonization. No genes putatively involved in pathogenesis were identified. Overall, our study suggests the safe application of selected strains as plant probiotics for sustainable agriculture.

Modified clay granules were used to promote Azotobacter vinelandii cell adhesion. The A. vinelandii cells in the clay granules were used as a biofertilizer and a plant material. The production process was carried out under variable temperatures. The raw ingredients consisted of clay, sawdust waste, and spent coffee grounds in different ratios. Scanning electron microscopy (SEM) was used to analyze the microstructure. The results of the study showed the addition of sawdust waste and spent coffee grounds had increased the water absorption of the fired clay granules based on their porosity. However, increasing the firing temperature in the range of 900 degrees C- 1100 degrees C decreased the water absorption and porosity and increased the bulk density of the fired clay granules. A. vinelandii was enriched to be used as a cell suspension. The fired clay granules were immersed in a cell suspension to immobilize the A. vinelandii cells for 48 h. The SEM-based investigations indicated that the fired clay granules were suitable for containing A. vinelandii cells. The results demonstrated high viability of bacterial cells fixed in the fired clay granules at 2.7x 10(7) CFU/g. Furthermore, the test results of bacterial cells in the fired clay granules for marigold planting media revealed that it had effectively encouraged plant growth. The nitrogen-fixing bacterial cells in the clay granules obtained from this research were determined to be appropriate for use as an ecological soil replacement in the future.

Aloe barbadensis is a drought-tolerant perennial medicinal plant with both nutritional and cosmetic uses. Drought is one of the main abiotic stresses limiting plant growth and development. However, the use of drought-resistant plants combined with beneficial soil micro-organisms could improve the effectiveness of biological methods to mitigate drought damage. This research aims to evaluate the effects of Funneliformis mosseae (MF), plant growth-promoting rhizobacteria (PGPR) (including Pseudomonas putida and Pantoea agglomerans), and their co-inoculation on the macronutrient status, antioxidant enzyme activities, and other morphophysiological traits of A. barbadensis under four irrigation regimes [25%, 50%, 75% and 100% of water requirement (WR)]. Three harvests were conducted, revealing that inoculation enhanced the survival rate and shoot fresh weight (SFW) compared to the control plants. However, at 25% WR, the SFW was reduced by 43% more than the control. across all harvests, while the PGPR + MF treatment showed increases of more than 19%, 11%, and 17% compared to the control, MF, and PGPR treatments, respectively. The results also showed that A. barbadensis exhibited innate drought tolerance up to a 50% WR level by enhancing physiological defenses, such as antioxidant enzyme activity. Inoculation increased the macronutrient status of the plant at all levels of irrigation regimes especially under severe drought conditions. The highest levels of nitrogen (N) (16.24 mg g(-1) DW) and phosphorus (P) (11.29 mg g(-1) DW) were observed in the PGPR + MF treatment at 100% WR. The maximum relative water content under MF inoculation and 75% WR (98.24%) (98.24%) was reached. PGPR + MF treatment alleviated drought-induced osmotic stress, as indicated by reduced antioxidant enzyme activities and electrolyte leakage. However, P. putida and P. agglomerans strains alone or in combination with F. mosseae increased plant yield, macronutrient uptake and antioxidant enzyme activity. This study underscores the potential of these PGPR and MF strains as invaluable biological tools for the cultivation of A. barbadensis in regions with severe drought stress.

Drought, soil salinization and the extreme heat events increments associate to climate change will notably impact sensitive crop species, such as strawberry. A greenhouse experiment was arranged to evaluate the potential of a PGPR-based biofertilizer, with multiple PGP properties, including ACC deaminase production highly related to the limitation of ethylene levels under abiotic stress, in modulation of photosynthetic apparatus tolerance responses by severe drought (complete water withholding), salinity in irrigation water (340 mM NaCl) and short extreme heat event (37/28 degrees C maximum and minimum temperature range). Our results show that all stress factors triggered acute injury effects on strawberry carboxylation capacity and photosystem II energy assimilation efficiency ability; whose intensity varied depending on factor nature. However, bacterial inoculation diminished similar to 67 %, 20 % and 18 % the deleterious impact imposed by drought, heat and salinity stress on the net photosynthetic rate (A(N)). This effect was primarily mediated by counterbalancing the diffusion of CO2 in the stomata and biochemical limitations in response to heat and salinity stress, while the reduction of biochemical damage was more notable in response to drought. Complementarily, inoculation was able to highly buffer the photochemical limitations imposed by all abiotic stress factors tested. Despite these positive effects, the application of PGPR-based biofertilizer was unable to completely reverse the impact of stress factors on strawberry photosynthesis metabolism. However, the signal of these ameliorative effects was significant enough to consider the implementation of PGPR-based biofertilizer application as a complementary tool in the management of strawberry cultivation in increasingly stressful agronomic contexts.