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Water scarcity and global food requirements are two major issues currently that need to be dealt with as soon as possible. Aerobic rice, grown without submergence and requiring occasional irrigation, offers a sustainable solution to water scarcity, contributing to sustainable agriculture. In the present study, nine experimental treatments, consisting of application methods of gel-biofertilizers (seed treatment, soil treatment, and seed + soil treatment) and split application of potassium (at basal, 30DAS, and 50DAS), along with one control, were replicated thrice. Results revealed that application of gel-biofertilizers as seed and soil treatment along with 3 equal splits of potassium recorded significantly higher plant height (97.65 cm), dry weight (27.08 g), panicles/m² (267.20), grain yield (3.35 t/ha), and stover yield (7.47 t/ha). Maximum gross returns (1,80,311.47 INR/ha), net returns (1,10,126.61 INR/ha), and benefit:cost ratio (1.57) were also recorded with the same treatment. Hence it is concluded that application of gel-biofertilizers as seed and soil treatment along with 75% recommended dose of fertilizers with 3 split applications of potassium gives a higher benefit:cost ratio over control (100% RDF). [ABSTRACT FROM AUTHOR]

A whole genome sequence of a new strain of the nitrogen-fixing bacterium Azospirillum doebereinerae, known for its diverse plant growth-promoting bacteria (PGPB), was obtained for the first time. The strain, designated Azospirillum doebereinerae AT, was isolated during a soil analysis in the Chernevaya taiga of Western Siberia, a unique and fertile forest ecosystem known for its diverse plant growth-promoting bacteria (PGPB). The A. doebereinerae genome under study is fully assembled into seven circular molecules, none of which are unequivocally plasmids, with a total length of 6.94 Mb and a G + C content of 68.66%. A detailed phylogenomic analysis confirmed its placement within the genus Azospirillum, specifically closely related to A. doebereinerae GSF71T. Functional annotation revealed genes involved in nitrogen metabolism, highlighting the potential of strain TA as a biofertilizer and plant growth-promoting agent. The findings contribute to our understanding of the genomic diversity and metabolic potential of the Azospirillum genus, and they are of interest for further study in the field of comparative bacterial genomics, given the strain's multi-chromosomal genome structure. [ABSTRACT FROM AUTHOR]

A field experiment was conducted during rabi season (September to January) of 2021 and 2022 at the experimental farm of Integral Institute of Agricultural Science and Technology, Integral University, Lucknow, Uttar Pradesh, India. The objective of the experiment is to find out the most efficient combination of different organic and inorganic sources of nutrients to increase the growth, yield characteristics of cauliflower. Total nine numbers of treatments along with the control treatment were assessed in Randomized Block Design with three numbers of replications. In view of, effect of different organic and inorganic sources of nutrients has observed significant variation. The result revealed that the growth parameters like plant height (5.57, 12.47, 19.77 cm), number of leaves (7.97, 9.53, 13.7), length of leaves (17.30, 24.73, 31.73 cm), width of leaves (7.17, 10.20, 15.10 cm), plant spread (285.50, 806.93, 1212.83 cm) at 20, 40 and 60 days respectively, yield parameters like weight of curd (893.73 g), yield of curd plot-1 (13.40 kg), yield of curd ha-1 (25.30 t) were observed higher in 75% N through RDF+25% N through FYM+Azotobacter @ 5 kg ha-1 (T4). INM treatments showed lesser result on growth and yield of cauliflower in T1 (control). The treatment T4 were the most beneficial treatment which may be followed for commercial cauliflower cultivation on large scale. Thus, farmers are suggested to apply 75% N through RDF+25% N through FYM+Azotobacter @ 5 kg ha-1 to increase growth and yield of cauliflower. [ABSTRACT FROM AUTHOR]

A study was done during two consecutive seasons of 2022/2023 and 2023/2024 to study the effects of humic acid (HU 4, 8, and 12 kg/hectare) as the main plot and BM (Azotobacter chrococum, Azospirulm Brasiliense, and Bacillus polymaxa) and algae extracts (ALG) as the subplot as well as their interactions on plant growth. The design of the experiment was a split plot, including 16 treatments and three replicates. The results showed that the growth parameters, fruit yield measurement, and oil production were noticeably enhanced using humic acid and biostimulants (BM and ALG). In this concern, the high-rise values were obtained by utilizing the high level of HU (12 kg/hectare) with bio-fertilizer (BM + ALG) application compared with control during both seasons. Also, GCMS analysis of the volatile oil revealed that HU and a mixture of bacteria and algae extract had improved the primary volatile oil components of coriander (Linalool - α-Pinene - γ-Terpinene - P-Cymene - Geranial Acetate).

The diversity of phage-related sequences (PRSs) and their site-specific integration into the genomes of nonpathogenic, agriculturally valuable, nitrogen-fixing root nodule bacteria, such as Sinorhizobium meliloti, were evaluated in this study. A total of 314 PRSs, ranging in size from 3.24 kb to 88.98 kb, were identified in the genomes of 27 S. meliloti strains. The amount of genetic information foreign to S. meliloti accumulated in all identified PRSs was 6.30 Mb. However, more than 53% of this information was contained in prophages (Phs) and genomic islands (GIs) integrated into genes encoding tRNAs (tRNA genes) located on the chromosomes of the rhizobial strains studied. It was found that phiLM21-like Phs were predominantly abundant in the genomes of S. meliloti strains of distant geographical origin, whereas RR1-A- and 16-3-like Phs were much less common. In addition, GIs predominantly contained fragments of phages infecting bacteria of distant taxa, while rhizobiophage-like sequences were unique. A site-specific integration analysis revealed that not all tRNA genes in S. meliloti are integration sites, but among those in which integration occurred, there were "hot spots" of integration into which either Phs or GIs were predominantly inserted. For the first time, it is shown that at these integration "hot spots", not only is the homology of attP and attB strictly preserved, but integrases in PRSs similar to those of phages infecting the Proteobacteria genera Azospirillum or Pseudomonas are also present. The data presented greatly expand the understanding of the fate of phage-related sequences in host bacterial genomes and also raise new questions about the role of phages in bacterial–phage coevolution. [ABSTRACT FROM AUTHOR]

An open-field experiment was conducted in Cabuyao, Laguna, Philippines to investigate the effects of combining chemical fertilizers, vermicompost, arbuscular mycorrhizal fungi (AMF), and nitrogen-fixing bacteria (Azospirillum spp.) on the growth, nutrient uptake, and yield of tomato plants. The experiment was arranged in a randomized complete block design replicated four times. The treatments include the recommended rate of chemical fertilizer (RRC) and three integrated nutrient management (INM) strategies. The results revealed that AMF inoculation significantly increased the uptake of P, K, Ca, and Mg while INM 3 recorded the highest N uptake. Treatments with vermicompost application recorded a significantly higher uptake of Cu. INM 1, INM 2, and INM 3 gave a significantly higher fruit yield than the RRC with an increase of 8%, 13%, and 14%, respectively. The percentage of mycorrhizal root colonization and number of rhizosphere spores were higher in mycorrhizal plants. Fruit yield and AMF root colonization were positively correlated with the uptake of several nutrients. INM strategies obtained a higher net income than the current fertilizer recommendation by 4–15%. These findings imply that the INM strategies can increase tomato productivity, reduce the amount of chemical fertilizer inputs, increase profitability, and potentially lead to soil health and environmental benefits. [ABSTRACT FROM AUTHOR]

A study was done during two consecutive seasons of 2022/2023 and 2023/2024 to study the effects of humic acid (HU 4, 8, and 12 kg/hectare) as the main plot and BM (Azotobacter chrococum, Azospirulm Brasiliense, and Bacillus polymaxa) and algae extracts (ALG) as the subplot as well as their interactions on plant growth. The design of the experiment was a split plot, including 16 treatments and three replicates. The results showed that the growth parameters, fruit yield measurement, and oil production were noticeably enhanced using humic acid and biostimulants (BM and ALG). In this concern, the high-rise values were obtained by utilizing the high level of HU (12 kg/hectare) with bio-fertilizer (BM + ALG) application compared with control during both seasons. Also, GCMS analysis of the volatile oil revealed that HU and a mixture of bacteria and algae extract had improved the primary volatile oil components of coriander (Linalool - α-Pinene - γ-Terpinene - P-Cymene - Geranial Acetate). [ABSTRACT FROM AUTHOR]

Seven auxin-producing endophytic bacterial strains (Azospirillum spp., Methylobacterium symbioticum, Bacillus spp.), and two different combinations of these strains were used to verify their influence on tomato during germination and development in hydroponic conditions where, as a novelty for Canestrino di Lucca cultivar, endophytic bacteria were inoculated. To emphasize the presence of bacterial auxins in roots and stems of seedlings, both in situ staining qualitative assessment and quantitative analysis were carried out. Moreover, hypogeal and epigeal growth of the plantlets were measured, and correlation analyses were conducted to examine the relationship between the amount of indolacetic acid (IAA) produced by the bacterial strains and root and stem parameters. Plantlets treated with microbial inoculants showed a significant increase in the survival rate compared to the control treatment. The best results as IAA producers were from Azospirillum baldaniorum Sp245 and A. brasilense Cd, which also induced significant root growth. On the other hand, Bacillus amyloliquefaciens and B. licheniformis induced the best rates in stem growth. These findings highlight the potential for using endophytic bacterial strains in a hydroponic co-cultivation system that enables inoculating plantlets, at an early stage of growth (5 days old). [ABSTRACT FROM AUTHOR]

Nitrogen is the most common limiting factor for crop productivity, and most maize cultivars require fertilizing. Here, we report on the possibility of partially replacing the nitrogenous fertilizer in sweet corn inoculated with a native strain of Azospirillum sp. in arid land on the coast of Peru. We performed an agronomic experiment in a crop field with arid soil under drip irrigation in Huacho (Peru) using a commercial variety of sweet corn. The treatments were two levels of nitrogen (90 and 180 kg N ha−1), one or two applications of a native strain of Azospirillum sp. (1 × 108 CFU/mL) and a control treatment with only nitrogen fertilizer. Eleven agronomic variables related to productive aspects were evaluated by performing statistical analyses and the comparison of treatment means. Inoculation with Azospirillum sp. did not significantly (p > 0.05) affect the total weight of ears, the number of ears per plant and the number of male flowers, but it significantly (p < 0.05) influenced the grain yield per hectare, the survival of plants, grain weight per plant, and the diameter and length of the cob. In some productive characteristics of sweet corn cv "Pardo", a significant effect was found following inoculation with Azospirillum sp., which outperformed the control with only nitrogen fertilization in grain yield, suggesting that it is possible to complement the application of nitrogen to soil with the inoculation of this strain, replacing up to 50% of the levels of fertilizer application, since the benefit/cost ratio increases. [ABSTRACT FROM AUTHOR]

Water scarcity and global food requirements are two major issues currently that need to be dealt with as soon as possible. Aerobic rice, grown without submergence and requiring occasional irrigation, offers a sustainable solution to water scarcity, contributing to sustainable agriculture. In the present study, nine experimental treatments, consisting of application methods of gel-biofertilizers (seed treatment, soil treatment, and seed + soil treatment) and split application of potassium (at basal, 30DAS, and 50DAS), along with one control, were replicated thrice. Results revealed that application of gel-biofertilizers as seed and soil treatment along with 3 equal splits of potassium recorded significantly higher plant height (97.65 cm), dry weight (27.08 g), panicles/m² (267.20), grain yield (3.35 t/ha), and stover yield (7.47 t/ha). Maximum gross returns (1,80,311.47 INR/ha), net returns (1,10,126.61 INR/ha), and benefit:cost ratio (1.57) were also recorded with the same treatment. Hence it is concluded that application of gel-biofertilizers as seed and soil treatment along with 75% recommended dose of fertilizers with 3 split applications of potassium gives a higher benefit:cost ratio over control (100% RDF).

A factorial experiment was conducted at the Research Station of the College of Agriculture, Anbar University, using the RCBD factorial experiments to determine the effect of the type of carrier and bacterial inoculum on the growth and yield of potatoes. Three carrier materials were used: pre-ripened date seeds, molasses, and zeolite as a control. B. megaterium and A. lipoferum carriers and inoculum were prepared and incubated for five days. The treatments were distributed randomly, adding the full fertilizer recommendation to the field, except P and N, which were added at a rate of 60% of the recommendation. The results showed that the carrier made from pre-ripe date seeds was superior to the zeolite, as the highest plant height and potato yield were recorded at 73.22 cm and 42.95 tons ha-1, with a significant difference from the lowest rate recorded for zeolite, 67.17 cm and 38.18 tons ha-1, respectively. Dpbm and molasses carriers recorded the highest percentages of N and P in soil, reaching 47.0, 45.98, 11.77, and 11.18 mg kg-1 soil, respectively. B. megaterium recorded the highest yields of potato and phosphorus in the soil, reaching 44 ton ha-1 and 9.86 mg Pkg-1. The interaction DpbB-B. megaterium recorded the highest average soil microbial content at 8.65 log cfu g-1. The molasses-A followed the lipoferum interaction with an average microbial content of 6.831 and 6.35.65 log cfu g-1.

Root research often uses rhizotron systems where their main characteristic is to possess a transparent wall allowing the in situ observation of plants' root system. Rhizotrons can vary in size and be filled with different substrates based on soil, sand and other components. Here, a simple and low cost rhizotron system without soil substrate was developed, allowing the observation of wheat (Triticum aestivum L.) root system treated with bioproducts. To show the effectiveness of the rhizotrons, hydrated wheat seeds were treated with plant growthpromoting bioproducts such as Azospirillum argentinense REC3 (106 CFU.ml-1), flagellin AzFlap (200 nM), or strawberry hydroalcoholic extract (0.01 mg.mL-1). This rhizotron system allowed to non-destructively evaluate the roots (length, density and root hair proliferation), where the values of the bioproducts surpassed the control. [ABSTRACT FROM AUTHOR]

Motile plant-associated bacteria use chemotaxis and dedicated chemoreceptors to navigate gradients in their surroundings and to colonize host plant surfaces. Here, we characterize a chemoreceptor that we named Tlp2 in the soil alphaproteobacterium Azospirillum brasilense. We show that the Tlp2 ligand-binding domain is related to the 4-helix bundle family and is conserved in chemoreceptors found in the genomes of many soil- and sediment-dwelling alphaproteobacteria. The promoter of tlp2 is regulated in an NtrC- and RpoN-dependent manner and is most upregulated under conditions of nitrogen fixation or in the presence of nitrate. Using fluorescently tagged Tlp2 (Tlp2-YFP), we show that this chemoreceptor is present in low abundance in chemotaxis-signaling clusters and is prone to degradation. We also obtained evidence that the presence of ammonium rapidly disrupts Tlp2-YFP localization. Behavioral experiments using a strain lacking Tlp2 and variants of Tlp2 lacking conserved arginine residues suggest that Tlp2 mediates chemotaxis in gradients of nitrate and nitrite, with the R159 residue being essential for Tlp2 function. We also provide evidence that Tlp2 is essential for root surface colonization of some plants (teff, red clover, and cowpea) but not others (wheat, sorghum, alfalfa, and pea). These results highlight the selective role of nitrate sensing and chemotaxis in plant root surface colonization and illustrate the relative contribution of chemoreceptors to chemotaxis and root surface colonization. [ABSTRACT FROM AUTHOR]

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The grain production area in the Brazilian agricultural region known as SEALBA, especially in Alagoas State, has seen significant growth in recent years. This study aims to contribute to sustainable regional development by evaluating the effects of inoculation, co-inoculation, and the application of starter mineral nitrogen (N), either individually or in combination, on soybean growth and yield. Eight field experiments were conducted from 2018 to 2021 in two municipalities within Alagoas, covering soybean cultivation areas ranging from the first to the fourth year. The experiments followed a randomized complete block design with four replications, employing a factorial arrangement of treatments. The first factor encompassed five levels related to inoculation technologies and N management: 1) Inoculation with Bradyrhizobium; 2) Inoculation with Bradyrhizobium combined with N basal fertilization; 3) Co-inoculation of Bradyrhizobium + Azospirillum; 4) Co-inoculation of Bradyrhizobium + Azospirillum + N fertilization at the base; and 5) Control treatment without microbiological inputs or nitrogen fertilizers. The second factor involved the evaluation of different soybean cultivars, with two materials assessed in 2018 and three cultivars in 2019, 2020, and 2021. Results demonstrated that seed inoculation with Bradyrhizobium led to increased soybean grain yield in first-year cultivation areas. However, N basal fertilization, commonly known as starter fertilization, did not result in yield improvements compared to the use of microbiological inputs alone. Soybean cultivars BRS 9383 IPRO and FTR 3191 IPRO exhibited greater responsiveness to seed inoculation with Bradyrhizobium.

Synthetic dyes are widely used in various branches of light industry. Due to the insuffi cient effi ciency of industrial painting processes, a large percentage of dyes end up in the wastewater of enterprises in an unmodifi ed form, which creates a huge risk of environmental pollution with these compounds. Triphenylmethane dyes, in particular malachite green, are toxic, allergenic and carcinogenic compounds. To date, biodegradability of triphenylmethane dyes has been shown for some bacteria and fungi producing phenol oxidase complex enzymes, including soil associative bacteria of the genus Azospirillum. Many factors are capable of inducing and inhibiting the biodegradation effi ciency, in particular the enzymatic systems that are involved in bleaching processes. In the present work we studied the eff ects of typical deactivating agents of phenol oxidases, such as H2 O2 , EDTA, SDS-Na, β-mercaptoethanol, dithiothreitol, Tween, and sodium azide, on the azospirilla’s phenol oxidases activity and the ability to decolorize malachite green. It was found that Tween and sodium azide do not have an inhibitory eff ect on azospirillum enzymes and exhibit a total stabilizing eff ect on the entire complex. An inhibitory eff ect from 60 to 100% was noted for laccase and Mn-peroxidase activity under the action of β-mercaptoethanol, dithiothreitol and EDTA, which is directly proportional to the decolorization rate of malachite green. Compared with the latest issues on classical phenol-oxidizing enzymes, our data revealed non-typical properties of the phenol oxidase complex enzymes of azospirillum.

A whole genome sequence of a new strain of the nitrogen-fixing bacterium Azospirillum doebereinerae, known for its diverse plant growth-promoting bacteria (PGPB), was obtained for the first time. The strain, designated Azospirillum doebereinerae AT, was isolated during a soil analysis in the Chernevaya taiga of Western Siberia, a unique and fertile forest ecosystem known for its diverse plant growth-promoting bacteria (PGPB). The A. doebereinerae genome under study is fully assembled into seven circular molecules, none of which are unequivocally plasmids, with a total length of 6.94 Mb and a G + C content of 68.66%. A detailed phylogenomic analysis confirmed its placement within the genus Azospirillum, specifically closely related to A. doebereinerae GSF71T. Functional annotation revealed genes involved in nitrogen metabolism, highlighting the potential of strain TA as a biofertilizer and plant growth-promoting agent. The findings contribute to our understanding of the genomic diversity and metabolic potential of the Azospirillum genus, and they are of interest for further study in the field of comparative bacterial genomics, given the strain’s multi-chromosomal genome structure.

The use of chemical inputs has led to the loss of microbial diversity involved in the N cycle, such as diazotrophic bacteria, which are inhibited by saturation of the receptors responsible for activating nitrogenase. Biological nitrogen fixation (BNF) in forage grasses can be used as an ecosystem service. The aim of this review was to analyze the contribution of forage grasses to BNF and their response to inoculation of non-symbiotic diazotrophs in order to find study opportunities. The analysis of the information was carried out using the prisma methodology of systematic reviews and meta-analyses. It should be noted that the main forage species that contribute to BNF are Brachiaria sp. and Pennisetum sp. The inoculation of Azospirillum sp. has generated a growth-promoting effect in grasses, but the response of the inoculated forage depends mainly on the synergy between plant and bacteria, showing neutral, antagonistic, and positive effects. [ABSTRACT FROM AUTHOR]

A fixação biológica de nitrogênio, promovida por bactérias do gênero Bradyrhizobium, além de substituir a adubação mineral, fornece nitrogênio suficiente para propiciar elevados rendimentos na cultura da soja. O objetivo do trabalho foi comparar a inoculação padrão de produto contendo Bradyrhizobium spp., aplicado isolado ou em associação com Azospirillum brasilense, com a pré-inoculação, via tratamento de sementes, na nodulação das plantas e produtividade de grãos da cultura da soja. O experimento foi implantado no mês de novembro de 2020 em quatro localidades (Mandaguaçu/PR, Marialva/PR, Paranavaí/PR e Itaquiraí/MS) com características edafoclimáticas distintas. Foi utilizado o delineamento em blocos casualizados, com sete tratamentos e cinco repetições. As variáveis avaliadas foram o número e massa seca de nódulos no início do florescimento, biomassa seca da parte aérea, teor de N e N-total na parte aérea e nos grãos e rendimento de grãos. Os resultados obtidos nos quatro ensaios permitiram concluir que a inoculação com Bradyrhizobium spp. + Azospirillum brasilense, via tratamento de sementes ou pulverização foliar do Azospirillum, mostrou-se tecnicamente viável na cultura da soja. [ABSTRACT FROM AUTHOR]

Plant growth-promoting bacteria (PGPB) that inhabit root rhizosphere of plants are of great agricultural importance due to their ability to produce phytohormones during root colonization. These phytohormones produce physiological changes in the plant that favor a greater absorption of nutrients, promote growth and increase production. This study analyzed the effect of inoculation of two of these bacteria, Azospirillum sp. and Pseudomonas fluorescens, under field conditions representative of the Andean Highlands. The experiment was carried out using flour corn seed of the INIAP-101 variety in a randomized complete block design with six repetitions. The treatments corresponded to: T1 (Azospirillum sp.), T2 (P. fluorescens), T3 (Azospirillum sp. and P. fluorescens), T4 (control, conventional chemical fertilization) and T5 (absolute control). The application of these bacteria significantly increased (p<0.05) the root length, the diameter of the cob, and the yield of fresh corn ("elotes" or "choclos"). The combined inoculation of these bacteria (T3) obtained the highest yield, with 19.70 t ha􀀀1 of fresh corn; while the chemical control and the absolute control got 17.12 and 13.58 t ha􀀀1 of fresh corn, respectively. The economic analysis of T3 reported a benefit/cost of 1.35, which indicates that the synergism of these two bacteria could be a sustainable strategy to improve yields and reduce the use of chemical fertilizers for corn production in the Andean region. [ABSTRACT FROM AUTHOR]

Due to the effect of herbicide on the soil, the natural fluorescence changes, and prevents the growth of bacteria that fix nitrogen an imbalance occurs between the organisms that live in the soil. Harmful organisms present in the soil increase until they become pests. Studying the effects of glyphosate on nitrogen-fixing bacteria like Azospirillum normally includes a combination of laboratory and field trials. An overarching framework for conducting such studies is outlined below. The average number of Azospirillum cells at each concentration and in the control group is shown by the mean values. There were more total counts of Azospirillum in the control group, suggesting a higher mean (8200.00) without glyphosate. There appears to be a dose-dependent effect of glyphosate on Azospirillum count, with the mean values decreasing as the concentration of glyphosate rises from 5% to 20%. The p-values give us an idea of how significant the results are. A p-value of 0.00001 for the 5% concentration level implies an extremely low likelihood of achieving the observed results if there were no meaningful effects. Work on the research began on 12/26/2022 in the laboratories affiliated with the College of Education for Pure Sciences, University of Mosul, and the work and writing of the research was completed within 7 months. [ABSTRACT FROM AUTHOR]

سابقه و هدف: با توجه به نیاز بالای کشور ایران به چای و کافی نبودن مقدار تولید داخلی، استفاده از کودهای شیمیایی جهت افزایش تولید در واحد سطح رو به افزایش است. کاربرد طولانی مدت کودهای شیمیایی به ویژه کودهای نیتروژن‌دار، سبب اسیدی شدن خاک باغ‌های چای شده و سلامت و کیفیت خاک را تحت تاثیر قرار داده است. از این رو، جست‌وجو برای یک روش جایگزین و کارآمد که کارایی آن به اندازه کودهای شیمیایی باشد و ضررهای ناشی از مصرف بی‌رویه کودهای شیمیایی را جبران نماید، ضروری است. مواد و روش‌ها: در این پژوهش ابتدا ریزوباکتری‌های بومی تثبیت کننده نیتروژن (آزوسپیریلیوم) و حل کننده فسفر از ریزوسفر گیاه چای جداسازی و سپس به عنوان کود زیستی در کشت گلدانی نهال‌های چای هیبرید چینی در پژوهشکده چای کشور در سال 1400 مورد استفاده قرار گرفتند. این آزمایش در قالب طرح بلوک کامل تصادفی با آرایش فاکتوریل در سه تکرار اجرا شد. فاکتورهای آزمایش شامل pH خاک در دو سطح (65/4 و 21/5) و تیمارهای کودی در پنج سطح شامل شاهد منفی (B)، کود شیمیایی بر اساس آزمون خاک (C)، کود زیستی باکتری تثبیت کننده نیتروژن (BN)، کود زیستی باکتری حل کننده فسفر (BP) و کود زیستی دارای باکتری‌های تثبیت کننده نیتروژن و حل کننده فسفر (BNP) بودند. پس از گذشت سه ماه از کشت نهال چای در گلدان-ها پیامد استفاده از این کودهای زیستی بر ویژگی‌های خاک و رشد گیاه چای مورد بررسی قرار گرفت. یافته‌ها:‌ مقدار pH خاک در تمامی تیمارهایی که کود زیستی دریافت نمودند نسبت به تیمارهای شاهد و کود شیمیایی بیشتر بود. بیشترین و کمترین مقدار نیتروژن خاک به ترتیب در تیمارهای BNP وB مشاهده شد. بیشترین مقدار فسفر فراهم خاک در تیمار BNP مشاهده شد که البته اختلاف معنی‌داری با تیمار و BN نداشت. مقدار پتاسیم قابل جذب خاک در تیمارهای دریافت کننده کود زیستی و شیمیایی اختلاف آماری معنی‌داری را نشان نداد. بیشترین و کمترین مقدار وزن تر، وزن خشک و محصول به ترتیب در تیمارهای BNP و B مشاهده شد. بیشترین محتوای نیتروژن و فسفر گیاه به ترتیب مربوط به تیمارهای BNP (8/4 درصد) و BP (24/0 درصد) بود. محتوای پتاسیم گیاه در تیمارهای کود زیستی بیشتر از تیمار شاهد بود، اگرچه درصد پتاسیم در تمامی تیمارهای کود زیستی از تیمار کود شیمیایی کمتر بود. نتیجه‌گیری: در این پژوهش، تیمار کودهای زیستی باکتری آزوسپیریلیوم و حل کننده فسفر به ترتیب سبب افزایش محتوای نیتروژن و فسفر گیاه چای و خاک زیرکشت آن شدند و کاربرد هم‌زمان آن‌ها سبب افزایش کارایی هردو شد. بنابراین، از آن‌جا که این باکتری‌ها سبب بهبود رشد گیاه و ویژگیهای خاک شدند به نظر می‌رسد رایزوباکترهای بومی جداشده از ریزوسفر چای پتانسیل استفاده در باغ‌های چای به عنوان کود زیستی را در راستای کشاورزی پایدار داشته باشند. اگرچه بررسی طولانی‌مدت در شرایط مزرعه طی چند دوره‌ی رشد و همچنین فصول مختلف سال برای ارزیابی‌های بیشتر مورد نیاز است.

IntroductionSouth of Iran has been located in the dry belt and desert strip thus water stress has always been one of the serious problems in its agriculture (Buzarjomehri et al., 2020). Intercropping is the cultivation of two or more plant species in a specific land and growing season, which is important in agricultural systems with limited resources and low input (Brooker et al., 2015). Due to the differences in the rooting depth, lateral expansion, and root density of cereals and legumes, they have been the best candidates for intercropping traditionally for limited soil water and nutrient availability environments (Babalola, 1980; Haynes, 1980). Application of bio-fertilizers (PGPR bacteria) that have nitrogen (N) fixation and phosphorus (P) solubilizing activity (Azospirillum brasilense and Pseudomonas fluorescence, respectively) is a promising approach for obtaining N, P, and water-restricted areas (Tien et al, 1979; Barea, 2015). Organic manures enhance soil water holding capacity and serve as excellent slow-release sources of nitrogen (N) and phosphorus (P) in the soil (Risse et al., 2006). This study aimed to investigate the effect of different fertilizer systems (chemical, integrated, and bio-organic) on triticale grain yield and its components in sole and intercropped triticale in triticale/chickpea system under late season water stress in a hot and dry area of southern Iran (Fars province - Darab). Materials and MethodsTo evaluate the yield and yield components of triticale (× Triticosecale Wittmack) in monoculture and intercropping with chickpea (Cicer arietinum L.) under late season water stress conditions, a split-factorial experiment in a randomized complete block design with three replications was implemented at the research field of the College of Agriculture and Natural Resources of Darab - Shiraz University in 2019-2020 growing season. Treatments were two levels of irrigation (Ir): [1- normal (IRN): irrigation based on the plant water requirement up to the physiological maturity stage (ZGS92) and 2- water stress (WS): irrigation based on the plant water requirement up to the milking stage] as the main plots and three fertilizer sources (FS) [1- chemical: ( 50 kg P ha-1 + 150 kg N ha-1), 2- integrated: (25 kg P ha-1 + 75 kg N ha-1 + 20 tons sheep manure ha-1 + inoculation with Pseudomonas fluorescens and Azospirillum brasilense) 3- bio-organic: 40 tons sheep manure ha-1 + inoculation with Pseudomonas fluorescens and Azospirillum brasilense] and two cropping systems (Cs) [1- monoculture of triticale, 2- intercropped triticale with chickpea (1:1)] as the sub-plots. Triticale grain yield and its components were measured and the harvest index (%) was calculated. Data were analyzed using SAS 9.1 software and the means were separated by the least significant difference (LSD) test at 5% probability level.Results and DiscussionThe results demonstrated that water stress reduced the grain yield and its components in triticale, with the extent of reduction varying among different treatments. In the Ir × Cs interaction, the Ws treatment reduced the triticale grain yield as compared to IRN by 38% and 55 % in the intercropped and sole-triticale, respectively. The Ir × Fs interaction showed that the grain yield decreased by water stress as a function of the fertilizer system (60.4%, 43.7%, and 30.7% reduction in the chemical, integrated, and bio-organic treatments, respectively). Evaluation of the results related to the triticale yield components (grain weight, biological yield, and harvest index) also showed that the Ws treatment reduced these traits. However, the least reduction occurred in bio-organic fertilizer as compared with the other fertilizer systems (significant Ir × Fs interaction). Furthermore, the Ir × Cs interaction showed that the Ws treatment reduced triticale grain weight and its biological yield as compared to IRN in both cropping systems with different manners. The least reduction of their traits by Ws treatment was showed in intercropped triticale as compared to its sole cropping.ConclusionBased on the results of this study, intercropped triticale with chickpea and using of bio-organic fertilizer were recommended for hot and dry areas of southern Iran where water stress may occur at the end of the growing seasons. Using these strategies leads to water stress alleviation and therefore less reduction of triticale grain yield in these environments.

An open-field experiment was conducted in Cabuyao, Laguna, Philippines to investigate the effects of combining chemical fertilizers, vermicompost, arbuscular mycorrhizal fungi (AMF), and nitrogen-fixing bacteria (Azospirillum spp.) on the growth, nutrient uptake, and yield of tomato plants. The experiment was arranged in a randomized complete block design replicated four times. The treatments include the recommended rate of chemical fertilizer (RRC) and three integrated nutrient management (INM) strategies. The results revealed that AMF inoculation significantly increased the uptake of P, K, Ca, and Mg while INM 3 recorded the highest N uptake. Treatments with vermicompost application recorded a significantly higher uptake of Cu. INM 1, INM 2, and INM 3 gave a significantly higher fruit yield than the RRC with an increase of 8%, 13%, and 14%, respectively. The percentage of mycorrhizal root colonization and number of rhizosphere spores were higher in mycorrhizal plants. Fruit yield and AMF root colonization were positively correlated with the uptake of several nutrients. INM strategies obtained a higher net income than the current fertilizer recommendation by 4–15%. These findings imply that the INM strategies can increase tomato productivity, reduce the amount of chemical fertilizer inputs, increase profitability, and potentially lead to soil health and environmental benefits.

Background and Objectives: Considering the high demand for tea in Iran and the insufficient local production, the use of chemical fertilizers to enhance production per unit area is increasing. The long-term use of chemical fertilizers, especially nitrogen fertilizers, in tea gardens has led to soil acidification which in turn impacted the soil quality and health. Therefore, searching for an alternative method that is as efficient as chemical fertilizers and compensates for the disadvantages caused by the excessive use of chemical fertilizers is essential in tea gardens nutrition. Materials and Methods: In this research, native nitrogen-fixing (Azospirillum) and phosphorus solubilizing rhizobacteria were isolated from the rhizosphere of tea plants and then used as biofertilizers for cultivation of Chinese hybrid tea seedlings at tea research center in 1400 under pot experiment. This experiment was conducted in a randomized complete block design with factorial arrangement and three replications. The factors include pH of soil at two levels (4.65 and 5.21), and fertilizer treatments at five levels including blank (B), control; where chemical fertilizer was applied based on soil analysis (C), nitrogen fixing bacteria was applied as biofertilizer (BN), phosphorus solubilizing bacteria was applied as biofertilizer (BP), and nitrogen fixing and phosphorus solubilizing bacteria were applied as biofertilizer (BNP). After three months of tea planting, the effect of applied biofertilizers on soil biochemical characteristics and yield of tea plant were investigated. Results: The soil pH values in all treatments that received biofertilizers were higher than that of the blank and control treatments. The highest and the lowest soil nitrogen (N) content were observed in BNP and B treatments, respectively. The highest content of soil phosphorus (P) was observed in BNP treatments, which P content in this treatment with BN was not significantly different. The soil available potassium content in treatments that receiving bio and chemical fertilizers did not show a statistically significant difference. The highest and the lowest values of fresh weight, dry weight and yield were observed in BNP and B treatments, respectively. The highest content of N and P in plant were observed in BNP (4.8%) and BP (0.24%) treatments, respectively. The potassium content of plant in treatments that received biofertilizers was lower than B, while the potassium content in all biofertilizer treatments were higher than that of the control. Conclusion: In this study biofertilizer treatments, Azospirillum and phosphorus solubilizing bacteria, increased the nitrogen and phosphorus contents in tea plant and soil, respectively. Since these bacteria improved plant growth and soil properties, it seems that native rhizobacteria isolated from tea rhizosphere have the potential to be used as biofertilizers in tea gardens in line with sustainable agriculture. Although, long term investigation during the several growth periods and different seasons of the year is needed for further evaluations. [ABSTRACT FROM AUTHOR]

Aldehyde dehydrogenases (ALDHs) are indispensable enzymes that play a pivotal role in mitigating aldehyde toxicity by converting them into less reactive compounds. Despite the availability of fully sequenced Azospirillum genomes in public databases, a comprehensive analysis of the ALDH superfamily within these genomes has yet to be undertaken. This study presents the identification and classification of 17 families and 31 subfamilies of ALDHs in fully assembled Azospirillum genomes. This classification system framework provides a more comprehensive understanding of the diversity and redundancy of ALDHs across bacterial genomes, which can aid in elucidating the distinct characteristics and functions of each family. The study also proposes the adoption of the ALDH19 family as a powerful phylogenetic marker due to its remarkable conservation and non-redundancy across various Azospirillum species. The diversity of ALDHs among different strains of Azospirillum can influence their adaptation and survival under various environmental conditions. The findings of this study could potentially be used to improve agricultural production by enhancing the growth and productivity of crops. Azospirillum bacteria establish a mutualistic relationship with plants and can promote plant growth by producing phytohormones such as indole-3-acetic acid (IAA). The diversity of ALDHs in Azospirillum can affect their ability to produce IAA and other beneficial compounds that promote plant growth and can be used as biofertilizers to enhance agricultural productivity. [ABSTRACT FROM AUTHOR]

The enhancing effect of N2-fixing bacterial strains in the presence of mineral N doses on maize plants in pots and field trials was investigated. The OT-H1 of 10 isolates maintained the total nitrogen, nitrogenase activities, IAA production, and detection of NH3 in their cultures. In addition, they highly promoted the germination of maize grains in plastic bags compared to the remainder. Therefore, OT-H1 was subjected for identification and selected for further tests. Based on their morphological, cultural, and biochemical traits, they belonged to the genera Azotobacter. The genomic sequences of 16S rRNA were, thus, used to confirm the identification of the genera. Accordingly, the indexes of tree and similarity for the related bacterial species indicated that genera were exactly closely linked to Azotoacter salinestris strain OR512393. In pot (35 days) and field (120 days) trials, the efficiencies of both A. salinestris and Azospirillum oryzea SWERI 111 (sole/dual) with 100, 75, 50, and 25% mineral N doses were evaluated with completely randomized experimental design and three repetitions. Results indicated that N2-fixing bacteria in the presence of mineral N treatment showed pronounced effects compared to controls. A high value of maize plants was also noticed through increasing the concentration of mineral N and peaked at a dose of 100%. Differences among N2-fixing bacteria were insignificant and were observed for A. oryzea with different mineral N doses. Thus, the utilization of A. oryzea and A. salinestris in their dual mix in the presence of 75 followed by 50% mineral N was found to be the superior treatments, causing the enhancement of vegetative growth and grain yield parameters of maize plants. Additionally, proline and the enzyme activities of both polyphenol oxidase (PPO) and peroxidase (PO) of maize leaves were induced, and high protein contents of maize grains were accumulated due to the superior treatments. The utilization of such N2-fixing bacteria was, therefore, found to be effective at improving soil fertility and to be an environmentally safe strategy instead, or at least with low doses, of chemical fertilizers. [ABSTRACT FROM AUTHOR]

The introduction of legumes into rotations can improve nitrogen use efficiency and crop yield; however, its microbial mechanism involved remains unclear. This study aimed to explore the temporal impact of peanut introduction on microorganisms related to nitrogen metabolism in rotation systems. In this study, the dynamics of diazotrophic communities in two crop seasons and wheat yields of two rotation systems: winter wheat – summer maize (WM) and spring peanut → winter wheat – summer maize (PWM) in the North China Plain were investigated. Our results showed that peanut introduction increased wheat yield and biomass by 11.6% (p < 0.05) and 8.9%, respectively. Lower Chao1 and Shannon indexes of the diazotrophic communities were detected in soils that sampling in June compared with those sampling in September, although no difference was found between WM and PWM. Principal co-ordinates analysis (PCoA) showed that rotation system significantly changed the diazotrophic community structures (PERMANOVA; p < 0.05). Compared with WM, the genera of Azotobacter, Skermanella, Azohydromonas, Rhodomicrobium, Azospirillum, Unclassified_f_Opitutaceae, and Unclassified_f_Rhodospirillaceae were significantly enriched (p < 0.05) in PWM. Furthermore, rotation system and sampling time significantly influenced soil properties, which significantly correlated with the top 15 genera in relative abundance. Partial least squares path modeling (PLS-PM) analysis further showed that the diazotrophic community diversity (alpha- and beta-diversity) and soil properties (pH, SOC and TN) significantly affected wheat yield. In conclusion, legume inclusion has the potential to stabilize diazotrophic community structure at the temporal scales and increase subsequent crop yield. [ABSTRACT FROM AUTHOR]

IntroductionTodays, efforts to increase crop yields have led to the indiscriminate use of chemical fertilizers, especially nitrogen (N) and phosphorus (P) fertilizers. It has caused soil and groundwater pollution and the destruction of soil microbial communities. Therefore, researchers should look for ways to replace N fertilizers and reduce their side effects. Intercropping of cereals and legumes due to differences in the distribution and depth of roots in the soil profile can reduce competition for water and the survival of these plants in water shortage conditions. Among the methods that may reduce the use of N and P fertilizers and thus reduce sensitivity to water stress is the intercropping of cereals and legumes. Using growth-promoting N-fixing bacteria such as Azospirillum brasilense and phosphorus solvents such as Pseudomonas fluorescens as biofertilizers can be another way to reduce the use of N and P fertilizers and the adverse effects of water stress. Therefore, the aim of this study was to investigate the effects of different fertilizer systems [chemical, integrated, and biological] on yield and competitive indices in triticale (× Triticosecale Wittmack) - chickpea (Cicer arietinum L.) intercropping under water stress conditions in Southern Iran (Fars province).Materials and MethodsThis experiment was performed as a split factorial on a randomized complete block design with three replications in the research farm of the Darab Faculty of Agriculture and Natural Resources-Shiraz University in the 2019-2020 growing season. Experimental treatments included two levels of irrigation (Ir) [Normal: irrigation based on plant water requirement (IRN) and water stress: irrigation based on plant water requirement up to the milking stage (WS)] as the main factors. The Sub-factors included three sources of fertilizer (F) [Chemical: 50 kg P.ha-1 +150 kg N.ha-1, Bio-organic: 40 tons of manure sheep ha-1 + inoculation with Pseudomonas fluorescens and Azospirillum brasillens, Integrated: 25 kg P ha-1 + 75 kg N.ha-1 + 20 tons of manure sheep ha-1 + inoculation with Pseudomonas fluorescens and Azospirillum brasilens] and three types of cropping systems (Cp) [Monoculture of triticale, monoculture of chickpea, and intercropping of triticale-chickpea (1:1)]. The crops Grain yield were measured, of the crops was measured and competitive indices including land equivalent ratio (LER), aggressivity (A), competitive ratio (CR), and system productivity index (SPI) were computed. The SAS 9.1 software was used to analyze the data, and the means were separated using the least significant difference (LSD) test at a 5% probability level.Results and Discussion The results showed that the cessation of irrigation after the milking stage put severe stress on the triticale and chickpea during the grain filling period and reduced grain yield of both plants. The Ir × F interaction for triticale and chickpea grain yield showed that the lowest reduction of their grain yield (31% and 27%, respectively) were obtained in Bio treatment due to water stress as compared to IRN. Furthermore, The Ir × Cp interaction for triticale and chickpea grain yield showed that the water stress reduced their grain yield. However, the reductions were lower in intercropping system of triticale (38%) and chickpea (24%) as compared with their sole cropping. Late season water stress increased triticale, chickpea and total LER as compared with IRN conditions by 40, 65 and 51%, respectively. Furthermore, the Ir × F interaction showed that the highest and the lowest reductions (55% and 17%, respectively) of SPI were achieved in chemical and Bio treatments as a consequence of water stress conditions. Conclusions Based on the results obtained from this study, it can be concluded that the intercropping system of triticale and chickpea is superior to their monocropping under late season water stress conditions. Also, the lowest reduction of chickpea and triticale grain yields as a consequence of water stress was obtained by the application of Bio and integrated fertilizers. Therefore, the use of Azospirillum brasiliens and Pseudomonas fluorescens with sheep manure fertilizer not only mitigates the negative effects of water stress, but also reduces the excessive use of N-P chemical fertilizers and their harmful environmental effects and it can be an effective step for sustainability of agricultural systems.

In this study, the antagonistic effect of five bacteria genera namely Bacillus, Pseudomonas, Azotobacter, Azospirillum, and Streptomyces isolated from rhizosphere of wheat were evaluated against Fusarium graminearum as potential biocontrol agents in vitro. F. graminearum was molecularly diagnosed using the Polymerase chain reaction (PCR) technique. Each bacteria were tested for the production of catalase enzyme, oxidase enzyme, analysis of starch, analyze of gelatin, and the motility, where Azotobacter, Azospirillum, and Bacillus subtilis were positive for all tested. Fungal inhibition tests were performed by using the dual culture method and agar well diffusion technique. Among them, Streptomyces and Azospirillum exhibited potent inhibition to the growth of F. graminearum (72.14% and 66.42%) respectively, followed by B.pumillus, P.fluorescens, B. subtilis and Azotobacter ( 58.28%, 43.23%, 39.71% and 35.71%) respectively as compared with the control treatment (0.0%).The dry weight of the fungus biomass was decreased with bacteria P. fluorescens, Streptomyces sp, Azotobacter sp, Azospirillum sp, B. subtilis, and B. pumillus which reached (0.114, 0.103, 0.147, 0.101, 0.143, and 0.107 g) respectively compared to the control treatment that was 0. 665 g.

La acelga es un cultivo hortícola de alto valor nutritivo y en México se producen más de 12 mil toneladas al año. Para su producción, estos cultivos requieren nutrientes, los cuales pueden ser aportados a través de soluciones de nutrientes minerales o biofertilizantes. Los biofertilizantes son productos que contienen microorganismos benéficos que mejoran la calidad del suelo y que favorecen el crecimiento de las plantas. Además, estos microorganismos realizan la fijación de nitrógeno y la solubilización de fosfato. El presente trabajo evaluó la aplicación de té de compost, co-inoculación (Azospirillum y Glomus) y fertilizante inorgánico sobre el crecimiento (raíz, tallo y hojas) y contenido de nutrientes en plantas de acelgas (Beta vulgaris var. Forhook Giant). El presente trabajo se llevó a cabo en un invernadero utilizando un diseño de bloques completos al azar. Las plantas de acelga tratadas con té de compost + fertilización inorgánica (CTIF) acumularon más peso seco en raíces y tallos (4.06 y 8.10 g respectivamente), por otro lado, el peso seco de la hoja aumentó bajo tres tratamientos: fertilización inorgánica (IF), té de compost + co-inoculación (CTCi) y CTIF (12.5, 9.22 y 10.5 g respectivamente). El área foliar fue mayor en los tratamientos IF y CTIF. El contenido de P y Mg también fue mayor en los controles (C). El tratamiento con CTCi aumentó el contenido de N, K y Mn; el tratamiento de coinoculación (Ci) incrementó el contenido de Cu, así como el tratamiento de CTIF incrementó los contenidos de Ca, Fe, Zn y B y en menor medida también los contenidos de P, Mg, Cu y Mn. El coeficiente de partición de biomasa indica que en seis muestreos (de un total de siete muestreos), la mayoría de los fotosintatos (PS) fueron utilizados por las plantas para formar o aumentar el tamaño de las hojas. Si se desea un método alternativo de fertilización, se recomienda utilizar una combinación de biofertilizante y fertilización inorgánica como la combinación de té de composta y solución mineral que aumentó la producción y la concentración de nutrientes en el cultivo de acelgas.

The soybean [Glycine max (L.) Merrill] relationship with the bacteria Bradyrhizobium japonicum is responsible for providing around 60% of the nitrogen (N) required for the crop and the remaining N comes from the soil or supplemental fertilization. To investigate if higher yields are possible, supplemental N studies and co-inoculation of Rhizobium with Azospirillum are necessary. This N rate (0, 30, 56, 112, 336 kg N ha−1) and inoculation study was conducted across eight environments in eastern North Dakota, USA, in 2021 and 2022. Also, the effect of supplemental N and co-inoculation on nodulation was evaluated. When N was applied at 112 kg N ha−1, nodulation was significantly inhibited. Co-inoculation increased the number of large nodules and the volume of nodules; however, the yield was not different from inoculation with B. japonicum. Nitrogen at 112 and 336 kg ha−1 increased grain yield, protein yield, and seed weight; however, the higher N rate decreased plant population. There were significant positive relationships between yield and protein content and seed weight, and negative relationships between oil and protein content, and yield and oil content. Based on a polynomial relationship, the highest yield (3711 kg ha−1) would be achieved at 273 kg N ha−1. The application of N resulted in a yield increase but using current prices may not be an economical choice. Additional research is necessary to verify if co-inoculation with efficient strains can improve biological N fixation. [ABSTRACT FROM AUTHOR]

IntroductionThe most important problem that threatens food security of any country and the world is the lack of adequate water resources, so one of the ways to deal with this crisis is to use plants with low water requirements and high water use efficiency. Among the plants, we can name Quinoa, which is one of the plants that has been less studied and exploited in Iran. Since the planting date has the greatest impact on the physiological characteristics of the crop compared to other cropping treatments, so choosing the appropriate planting date can also create the greatest correlation between plant growth trends and climatic conditions. Undoubtedly, the use of biological fertilizers, in addition to the positive effects it has on all soil properties, is also economically, environmentally and socially fruitful and can be a suitable and desirable alternative to chemical fertilizers. Therefore, the aim of this study was to determine the response to deficit irrigation, planting date and application of different biofertilizers in quinoa.Materials and MethodsThis experiment was carried out during two cropping years 2019 and 2020 in a farm located in Moghan region. The site has latitude of 39◦27 N, a longitude of 48◦12 E and is 120 m above mean sea level, with an average annual rainfall of 250-300 mm. In this experiment, Titicaca cultivar of quinoa was cultivated in summer in the form of a double split plot design based on a randomized complete block design with three replications. Experimental factors include irrigation at three levels (Conventional irrigation, Irrigation cut-off in budding stage and Irrigation cut-off in seed filling stage) as a main factor, planting date at three levels (27 July, 11 and 27 August) as a sub-factor and four levels of nitrogen biofertilizer (without inoculation, seed inoculation with Azotobacter, seed inoculation with Azospirillum and inoculation with a mixture of Azotobacter and Azospirillum) were considered as a sub-sub-factor. Plant height, stem diameter and panicle length in each plant were measured at the physiological maturity stage by randomly selecting 10 plants using a ruler with millimeter accuracy. Leaf area was measured by selecting 5 plants from each plot randomly and with the model Leaf area meter Li-cor. At the end of the growing season, the product of two middle planting lines with a length of 4 meters was harvested by observing the half-meter margin effect and after drying in a ventilated oven at 70 °C for 24 hours, grain yield was determined. Leaf carbon concentration was estimated by dry combustion with air flow in an electric furnace, Kjeldahl method (Sharpe et al., 2001) was used to measure nitrogen concentration. Experimental data were analyzed before analysis of variance for homogeneity of test errors through Bartlett test and then analyzed using SAS (9.1) software and comparison of means at 5% probability level using Duncan multi-range test.Results and DiscussionThe results showed that conventional irrigation with planting date of 27 August and inoculation of Azotobacter and Azospirillum biofertilizers had the best effect in terms of morphological traits and leaf nitrogen concentration and The highest grain yield (304.97 g.m-2) was obtained from conventional irrigation treatment with planting date of 27 August and inoculation of biofertilizers of Azotobacter and Azospirillum. Also, quinoa seed yield had a positive and significant correlation with plant height (r = 0.85), stem diameter (r =0. 64), leaf area (r = 0.86), panicle length (r = 0.86) and leaf carbon concentration (r = 0.38) showed.ConclusionThe results of this study showed though conventional irrigation with planting date of 20 August and inoculation of Azotobacter and Azospirillum biofertilizers had the highest number of studied traits, especially grain yield (304.97 g.m-2), but with interruption of irrigation treatment at the stage of seed filling with planting date of 20 August and inoculation of biofertilizers were included in a statistical group, so in terms of the importance of water consumption, it can be said that in conditions of limited water resources, irrigation cut-off treatment in the stage of grain filling has the most favorable results.

. Recently, much attention has been paid to the development of technologies for biodegradation of organopollutants and the search for promising biodestructors. The environmental accumulation of lignin-like compounds and synthetic dyes poses a huge threat not only to ecosystems and biodiversity, but also to human health. Phenol oxidases are enzymes with broad substrate specifi city, with oxidizing ability towards various polyphenols and aromatic amines. Therefore the use of phenol oxydases as bioremediation agents is promising due to their unique catalytic properties. In this work we present the results of a study of the eff ect of metal ions on the activity of the azospirilla phenol oxidase complex. It was demonstrated that extracellular laccases of lignin- and Mn-peroxidases of strains Azospirillum baldaniorum Sp245 and Azospirillum brasilense SR80 are quite stable in the presence of the studied metal salts. The enzymatic activity decreased and the eff ectiveness of the organopollutants’ biodegradation effi cacy was inhibited in the presence of Zn2+ ions. The laccase and lignin-peroxidase activity induced by copper ions positively correlated with the ability of lignin degradation by azospirillum. Analysis of the obtained data showed that inhibitors and inducers of authentic extracellular phenol oxidases of both fungi and bacteria are typical for azospirillum enzymes.

Co-inoculation between bacteria of the genera Bradyrhizobium and Azospirillum can enhance the nodulation and promote the development of the soybean [Glycine max (L.) Merrill] root system, contributing to the increase in grain yield, in addition to the reduction in production costs and contamination of natural resources. Cobalt (Co) and molybdenum (Mo) use can also favor biological nitrogen fixation. The research evaluated the co-inoculation effect of bacteria associated with the Co and Mo application in soybean crop. The randomized blocks design was employed, in a 2 x 6 factorial scheme, presence and absence of Co and Mo and five ways of using the products Bradyrhizobium and Azospirillum, plus control, with four replications. The treatments were formed by the control (not inoculated + 20 kg N ha-1); seed inoculation with Bradyrhizobium (100 mL ha-1) + 20 kg N ha-1; seed inoculation with Bradyrhizobium (100 mL ha-1) and three treatments applying Bradyrhizobium + Azospirillum in furrow, in different doses. Height of insertion of the first pod, total number of pods and grains per plant, weight of 100 grains and grain yield were evaluated. Inoculation of Bradyrhizobium japonicum associated with co-inoculation of Azospirillum brasilense via foliar and Co and Mo, provided increases in the number of pods per plant, number of grains per pod and weight of 100 grains, reflecting increases in grain yield. The use of Co and Mo, on average, increased soybean yield by 10%, resulting in an average yield of 4,904 kg ha-1. [ABSTRACT FROM AUTHOR]

Adaptation ex vitro is strongly stressful for microplants. Plant-growth-promoting rhizobacteria (PGPR) help to increase the adaptation potential of microplants transplanted from test tubes into the natural environment. We investigated the mechanisms of antioxidant protection of PGPR-inoculated potato microclones adapting to ex vitro growth in an aeroponic system. Potato (Solanum tuberosum L. cv. Nevsky) microplants were inoculated in vitro with the bacteria Azospirillum baldaniorum Sp245 and Ochrobactrum cytisi IPA7.2. On days 1 and 7 of plant growth ex vitro, catalase and peroxidase activities in the leaves of inoculated plants were 1.5-fold higher than they were in non-inoculated plants. The activity of ascorbate peroxidase was reduced in both in vitro and ex vitro treatments, and this reduction was accompanied by a decrease in the leaf content of hydrogen peroxide and malondialdehyde. As a result, inoculation contributed to the regulation of the plant pro/antioxidant system, lowering the oxidative stress and leading to better plant survival ex vitro. This was evidenced by the higher values of measured morphological and physiological variables of the inoculated plants, as compared with the values in the control treatment. Thus, we have shown some PGPR-mediated mechanisms of potato plant protection from adverse environmental factors under aeroponic conditions. [ABSTRACT FROM AUTHOR]

Agricultural plants are continuously exposed to environmental stressors, which can lead to a significant reduction in yield and even the death of plants. One of the ways to mitigate stress impacts is the inoculation of plant growth-promoting rhizobacteria (PGPR), including bacteria from the genus Azospirillum, into the rhizosphere of plants. Different representatives of this genus have different sensitivities or resistances to osmotic stress, pesticides, heavy metals, hydrocarbons, and perchlorate and also have the ability to mitigate the consequences of such stresses for plants. Bacteria from the genus Azospirillum contribute to the bioremediation of polluted soils and induce systemic resistance and have a positive effect on plants under stress by synthesizing siderophores and polysaccharides and modulating the levels of phytohormones, osmolytes, and volatile organic compounds in plants, as well as altering the efficiency of photosynthesis and the antioxidant defense system. In this review, we focus on molecular genetic features that provide bacterial resistance to various stress factors as well as on Azospirillum-related pathways for increasing plant resistance to unfavorable anthropogenic and natural factors. [ABSTRACT FROM AUTHOR]

Crop varieties differ in their ability to interact with Plant Growth-Promoting Rhizobacteria (PGPR), but the genetic basis for these differences is unknown. This issue was addressed with the PGPR Azospirillum baldaniorum Sp245, using 187 wheat accessions. We screened the accessions based on the seedling colonization by the PGPR and the expression of the phenylpyruvate decarboxylase gene ppdC (for synthesis of the auxin indole-3-acetic acid), using gusA fusions. Then, the effects of the PGPR on the selected accessions stimulating Sp245 (or not) were compared in soil under stress. Finally, a genome-wide association approach was implemented to identify the quantitative trait loci (QTL) associated with PGPR interaction. Overall, the ancient genotypes were more effective than the modern genotypes for Azospirillum root colonization and ppdC expression. In non-sterile soil, A. baldaniorum Sp245 improved wheat performance for three of the four PGPR-stimulating genotypes and none of the four non-PGPR-stimulating genotypes. The genome-wide association did not identify any region for root colonization but revealed 22 regions spread on 11 wheat chromosomes for ppdC expression and/or ppdC induction rate. This is the first QTL study focusing on molecular interaction with PGPR bacteria. The molecular markers identified provide the possibility to improve the capacity of modern wheat genotypes to interact with Sp245, as well as, potentially, other Azospirillum strains. [ABSTRACT FROM AUTHOR]

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The physiological and biochemical activity of plant–microbial associations enables them to determine the mobility, bioavailability, and accumulation of heavy metals in plant tissues. These abilities are the basis for the use of plants and their associated microorganisms in the development of approaches that ensure both the prevention of the ingress of toxic metals into food crops and the extraction of pollutants from polluted soils by using phytoremediation technologies. Whether plant–microbial complexes are used successfully depends on the knowledge of how specific organisms interact with heavy metals. We evaluated the effect of copper ions on common wheat (Triticum aestivum L.) inoculated with three plant-growth-promoting rhizobacteria (PGPR) of the genus Azospirillum. We analyzed the growth variables of 14-day-old wheat seedlings, the content of photosynthesis pigments, the activity of plant oxidoreductases, and the accumulation of copper by plant tissues. All strains more or less compensated for copper toxicity to seedling development and increased metal accumulation in roots and shoots. Copper affected the photosynthetic apparatus of the inoculated plants, primarily by decreasing the content of chlorophyll b. An analysis of the activity of plant oxidoreductases (peroxidases and phenoloxidases), which are involved in the physiological responses of plants to pollutant stress, showed strain-specific dependence and a significant effect of copper on the inoculated plants. Overall, the obtained results clearly show that the effect of Azospirillum on the physiological and biochemical status of wheat is diverse. The compensatory effect of bacteria on copper toxicity and the simultaneous increase in metal accumulation in plant tissues can be considered as mutually exclusive crop-production aspects associated with the growing of food plants in heavy-metal-polluted areas.

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

Biofilms represent the main mode of existence of bacteria and play very significant roles in many industrial, medical and agricultural fields. Analysis of biofilms is a challenging task owing to their sophisticated composition, heterogeneity and variability. In this study, biofilms formed by the rhizobacterium Azospirillum baldaniorum (strain Sp245), isolated biofilm matrix and its macrocomponents have for the first time been studied in detail, using Fourier transform infrared (FTIR) spectroscopy, with a special emphasis on the methodology. The accompanying novel data of comparative chemical analyses of the biofilm matrix, its fractions and lipopolysaccharide isolated from the outer membrane of the cells of this strain, as well as their electrophoretic analyses (SDS-PAGE) have been found to be in good agreement with the FTIR spectroscopic results. [ABSTRACT FROM AUTHOR]

The purpose of the research was to assess the potential effectiveness of Azospirillum baldaniorum Sp245 in stimulating the induction processes related to adventitious root formation. In this short communication, we present the preliminary results obtained for the first time for the Leccino olive cultivar (Olea europaea L.). Semi-hardwood cuttings were collected at different sampling times (autumn, winter, and spring) and subjected to root-inductive treatments with Azospirillum baldaniorum strain Sp245 (AZO) and indole-3-butyric acid (IBA), the most employed synthetic auxin used in nursery production of olive plants. Moreover, two growing substrates, perlite (an inorganic medium) and Elepot® (a blend of peat, coconut fiber, and perlite) were tested. Histological assays were carried out to identify the main cellular changes leading to adventitious root formation. The highest rates of cuttings showing more advanced stages of rooting inductive signals were observed with the spring sample. The events observed after AZO treatments were comparable to those observed with IBA, which were mainly associated with the Elepot® growing substrate. The positive responses of semi-hardwood cuttings of Leccino cultivar to AZO could provide the possibility of replacing IBA and develop perspectives in a context of organic nursery systems where alternative compounds, able to improve the rooting rate of cuttings, could substitute the non-permitted synthetic rooting agents. AZO induced significant cellular activities and could be considered a valid alternative rooting agent. [ABSTRACT FROM AUTHOR]