Rhizobium Sp Research Articles

Stenotrophomonas sp. LIMN, Enterobacter sp. LCMG, and Rhizobium sp. WFRFC: A Bacterial Consortium in the Production of Zea mays L. Under Different Agronomic Management Practices.

Objective: To evaluate the effect of the bacterial consortium Enterobacter sp. LCMG, Rhizobium sp. WFRFC, and Stenotrophomonas sp. LIMN on three different agronomic management practices in maize (Zea mays L.) cultivation, with the question: Does the consortium of bacterial strains have a positive influence on maize production under different cultivation practices in the Ciénega region, Jalisco? Design/methodology/approach: Treatments evaluated were TM= 100 % traditional management + bacterial consortium (BC), TM+AM= 50 % traditional management + 50 % agroecological management + BC, and AM= 100 % agroecological management + BC. A randomized complete block design was established, and agronomic and yield variables were evaluated. Results: The MT+MA treatment generated a 6.03 % increase in grain yield; generated a 10.35 % increase in ear height, a 4.87 % decrease in plant height, and a 50 % decrease in the consumption of synthetic products. Limitations on study/implications: The agronomic management was carried out according to the practices of the region's farmers. Findings/conclusions: The bacterial consortium Enterobacter sp. LCMG, Rhizobium sp. WFRFC, and Stenotrophomonas sp. LIMN had a positive effect on maize cultivation for grain production, particularly when combined with agronomic management consisting of 50 % traditional management + 50 % agroecological management. The bacterial consortium could be used as a bio-stimulant in maize production in the Ciénega region, Jalisco.

Pollution pressure drives microbial assemblages that improve the phytoremediation potential of heavy metals by Ricinus communis

Due to the rapid expansion of industrial activity, soil pollution has intensified. Plants growing in these polluted areas have developed a rhizobiome uniquely and specially adapted to thrive in such environments. However, it remains uncertain whether pollution acts as a sufficiently selective force to shape the rhizobiome, and whether these adaptations endure over time, potentially aiding in long-term phytoremediation. Therefore, in the present study, we aimed to compare whether the microbiome associated with roots from plants germinated in polluted riverbanks will improve the phytoremediation of Cd and Pb under mesocosm experiments compared with plants germinating in a greenhouse. The experimental design was a factorial 2 × 2, i.e., the origin of the plant and the presence or absence of 100 mg/L of Cd and 1000 mg/L of Pb. Our results showed that plants germinated in polluted riverbanks have the capacity to accumulate twice the amount of Pb and Cd during mesocosm experiments. The metagenomic analysis showed that plants from the river exposed to heavy metals at the end of mesocosm experiments were rich in Rhizobium sp. AC44/96 and Enterobacter sp. EA-1, Enterobacter soli, Pantoea rwandensis, Pantoea endophytica. In addition, those plants were uniquely associated with Rhizobium grahamii, which likely contributed to the differences in the levels of phytoremediation achieved. Furthermore, the functional analysis revealed an augmented functional potential related to hormones, metallothioneins, dismutases, and reductases; meanwhile, the plants germinated in the greenhouse showed an unspecific strategy to exceed heavy metal stress. In conclusion, pollution pressure drives stable microbial assemblages, which could be used in future phytostabilization and phytoremediation experiments.Graphical

Regulating Cotton Growth via Rhizobium Species

Unpredictable precipitation is a common problem for plant growth in India’s Deccan plateau, which is known for its poor soil and frequent droughts. Critical to the regulation of plant diseases and the enhancement of plant growth are root-colonizing rhizobacteria like Rhizobium. Isolating productive Rhizobium species from soil around the Eturnagram region’s cotton rhizosphere was the goal of a study carried out at Palamuru University. Rhizobium variant-5, currently known as Rhizobium sp. PKS [NCBI-OK663003, NCMR-MCC4960], was one of five different strains of Rhizobium isolated using the top layer method. It showed strong support for the growth of six different cotton cultivars. Out of the six cotton varieties tested, the Mahyco cultivar had the lowest proline levels while having higher amounts of IAA, proteins, chlorophyll, and sugars. The effectiveness of Mahyco was confirmed by experimental field testing conducted in four distinct cotton agricultural soils of Mahabubnagar District using Rhizobium sp. PKS [NCBI-OK663003, NCMR-MCC4960]. Deep black soil showed improved phytohormone synthesis and good biochemical alterations, whereas shallow black soil showed that the strains considerably enhanced plant development. Based on these results, the novel Rhizobium sp. PKS could be used as a bioinoculant in cotton fields on the Deccan plateau, which could improve agricultural yields despite the harsh conditions.

Production of vegetables with biofertilizers based on native microorganisms: A case study in Tixtla, Guerrero, Mexico

In agriculture, the use of fertilizers has increased due to the high demand for food by humanity, causing negative impacts because of high production costs and soil contamination. We evaluated five biofertilizers based on native microorganisms promoters of plant growth (NMPPG) as an alternative to the fertilizers used by small vegetable producers. The evaluation was carried out with three types of vegetables (lettuce, celery and epazote) in the Juan Berbera Catalán Irrigation Unit made up by producers from the community of Tixtla, Guerrero. The results show that Rhizobium sp. R01 (Tx3), Azotobacter sp. C3 (Tx1) and Bacillus licheniformis M2-7 (Tx5) used as biofertilizers promote germination and considerably increase fresh weight in these crops, and Azospirillum sp. M9 (Tx2) and Trichoderma sp. ABC1 (Tx4) present significant differences with the negative and chemical control. The yield of lettuce, celery and epazote was favored using biofertilizers, which can be considered a good alternative to apply to these crops, likewise, the price of biofertilizers (5 liters per Tx) compared to the fertilizer DAP-18-46-00 (50 kg) used by the same producers is $1,200.00 vs. $2,000.00 MXN per hectare produced respectively. In conclusion, the biofertilizers used herein represent a feasible alternative for farmers without disregarding the need for technical specialists and producers to identify optimal conditions that support the sustained application and management of biofertilizers.

Biocontrol of tomato pathogens by Bacillus subtilis F62 and its synergistic action in plant growth promotion with Rhizobium sp. L5

ABSTRACT Plant growth-promoting rhizobacteria (PGPR) are recognised for inhibiting pathogens and increasing plant biomass and yield. This study aims to evaluate the antagonistic potential of Bacillus subtilis F62 against fungal diseases of tomatoes and investigates its capability for promoting the growth of tomato seedlings using single-strain inoculation and co-inoculation with Rhizobium sp. L5. The in vitro antagonism of B. subtilis F62 against Alternaria sp., Botrytis sp., Fusarium sp., and Stemphylium sp. was assessed through dual-culture and volatile compounds assays. Furthermore, the antagonism against Botrytis sp. was also evaluated in harvested tomatoes. The growth promotion experiment involved treating tomato seeds with bacterial suspensions through soil drenching and seed soaking. Our results demonstrated the inhibitory ability of B. subtilis F62 against all fungal species, reducing the mycelial growth speed index from 54.7% to 76.6% in the dual-culture assay, and from 14.1% to 70.6% through antagonism via volatile compounds. This bacterium also decreased the incidence and severity of Botrytis sp. by 21% and 18.8%, respectively, in harvested tomatoes. Additionally, the growth promotion assay revealed that co-inoculation of B. subtilis F62 and Rhizobium sp. L5 increased leaf area and root dry weight compared to single-strain inoculation. Therefore, B. subtilis F62 is a promising bacterium for the biocontrol of tomato diseases and an effective plant growth-promoting rhizobacterium, demonstrating its synergistic effect when co-inoculated with Rhizobium sp. L5 on tomato seeds.

Deciphering the interaction of bacteria inoculants with the recipient endophytic community in grapevine micropropagated plants.

Engineering the plant microbiome with beneficial endophytic bacteria can improve the growth, health, and productivity of the holobiont. Here, we administered two beneficial bacterial strains, Kosakonia VR04 sp. and Rhizobium GR12 sp., to micropropagated grapevine cuttings obtained via somatic embryogenesis. While both strains colonized the plant endosphere, only Rhizobium GR12 sp. increased root biomass under nutritional-deficit conditions, as supported by the plant growth promotion traits detected in its genome. Phylogenetic and co-occurrence analyses revealed that the plant native bacterial community, originally dominated by Streptococcaceae and Micrococcaceae, dramatically changed depending on the inoculation treatments, as invading strains differently affected the relative abundance and the interactions of pre-existing taxa. After 30 days of plantlets' growth, Pantoea became a predominant taxon, and considering untreated plantlets as references, Rhizobium sp. GR12 showed a minor impact on the endophytic bacterial community. On the other hand, Kosakonia sp. VR04 caused a major change in community composition, suggesting an opportunistic colonization pattern. Overall, the results corroborate the importance of preserving the native endophytic community structure and functions during plant microbiome engineering.IMPORTANCEA better comprehension of bacterial colonization processes and outcomes could benefit the use of plant probiotics in the field. In this study, we applied two different beneficial bacteria to grapevine micropropagated plantlets and described how the inoculation of these strains impacts endophytic microbiota assembly. We showed that under nutritional deficit conditions, the response of the receiving endophytic bacterial communities to the invasion of the beneficial strains related to the manifestation of plant growth promotion effects by the inoculated invading strains. Rhizobium sp. GR12 was able to preserve the native microbiome structure despite its effective colonization, highlighting the importance of the plant-endophyte associations for the holobiont performance. Moreover, our approach showed that the use of micropropagated plantlets could be a valuable strategy to study the interplay among the plant, its native microbiota, and the invader on a wider portfolio of species besides model plants, facilitating the application of new knowledge in agriculture.

Complete genome sequences of Rhizobium sp. strain SL42 and Hydrogenophaga sp. strain SL48, microsymbionts of Amphicarpaea bracteata

This study comprehensively analyzed two distinct rhizobacterial strains, Rhizobium sp. SL42 and Hydrogenophaga sp. SL48, through whole genome de novo sequencing. Isolated from root nodules of Amphicarpaea bracteata, a native legume related to soybean, they were selected to explore beneficial rhizobacteria from native plant relatives. Utilizing Illumina and Nanopore sequencers and MaSuRCA assembly, their complete genetic information was elucidated. Rhizobium sp. SL42 has a 4.06 Mbp circular chromosome and two plasmids with 60% GC content, while Hydrogenophaga sp. SL48 exhibits a 5.43 Mbp circular chromosome with 65% GC content. Genetic analysis identified them as new species, supported by ANI values (77.72% for SL42 and 83.39% for SL48) below the threshold. The genomic analysis unraveled a plethora of genes encoding diverse metabolic functions, secretion systems for substance transport, quorum sensing for coordination, and biosynthetic gene clusters suggesting the production of bioactive compounds. These functional properties contribute to plant growth stimulation, reflecting the symbiotic relationship of rhizobacteria with plants, potentially involving nitrogen fixation and growth-promoting compounds. This research contributes valuable knowledge about plant-microbe interactions and plant growth promotion by these two strains of rhizobacteria.

Coculture of bacterial levans and evaluation of its anti-cancer activity against hepatocellular carcinoma cell lines

This research represents a novel study to assess how coculture affects levan yield, structure, bioactivities, and molecular weight. Among the 16 honey isolates, four bacterial strains recorded the highest levan yield. The Plackett–Burman design showed that the coculture (M) of isolates G2 and K2 had the maximum levan yield (52 g/L) and the effective factors were sucrose, incubation time, and sugarcane bagasse. The CCD showed that the most proper concentrations for maximum levan yield (81 g/L): were 130 g/L of sucrose and 6 g/f of sugarcane bagasse. Levan’s backbone was characterized, and the molecular weight was determined. G2 and K2 isolates were identified based on 16 sRNA as Bacillus megaterium strain YM1C10 and Rhizobium sp. G6-1. M levan had promising antioxidant activity (99.66%), slowed the migration activity to a great extent, and recorded 70.70% inhibition against the hepatoblastoma cell line (HepG2) at 1000 µg/mL. Gene expression analysis in liver cancer cell lines (HePG2) revealed that M levan decreased the expression of CCL20), 2GRB2, and CCR6) genes and was superior to Doxo. While increasing the expression of the IL4R and IL-10 genes. The DNA damage values were significantly increased (P < 0.01) in treated liver cancer cell lines with levan M and Doxo. The results referred to the importance of each of the hydroxyl and carboxyl groups and the molecular weight in levans bioactivities.

In silico characterization of nifH gene of Rhizobium sp. TN04 isolated from the rhizosphere of non-leguminous potato plants

In silico characterization of nifH gene of Rhizobium sp. TN04 isolated from the rhizosphere of non-leguminous potato plants

IMPACT OF RHIZOSPHERIC, NODULATION AND SOIL MICROBIOME ON SOYBEAN AND RICE GROWTH FOR SUSTAINABLE AGRICULTURE

Microorganisms are critical for the survival of life on Earth, but we know very little about the vast majority ofmicrobes. We studied the culturable soybean root, soil, and nodules microbiome here. Thirty bacterial sampleswere isolated from different localities of soybean crops, including soil, root, and nodules, to assess their abilityfor plant growth promotion. To evaluate the richness and diversity in the root and soil, we performed the mostprobable number (MPN) test. Seven of the bacterial isolates were able to produce cellulase, in which JSW1 andJSW6 were most efficient with 2.56 and 2.05 cellulolytic index. All isolates were able to grow and utilizedpectin, in which JSW2 and JSW3 were most efficient with 0.8 and 0.66 pectinolytic index. Pikovskaya mediamodified with TCP JSW1 and JSW2 showed a 3.0 and 2.33 solubility index, and on CaCO 3 media, the JSW1strain produced a 1.58 solubilization index. All bacterial isolates were phylogenetically identified by sequencingand analyzing the 16S rRNA gene. Under controlled conditions, consortia, Pantoea dispersa, and Rhizobiumsp. isolates considerably improved rice root dry weight by 53%, 75%, and 69% and shoot dry weight by 85%,71%, and 76%. Based on in vitro characterization, the potential bacteria Pantoea dispersa, Pseudomonaskoreensis, and Rhizobium sp. were selected to be evaluated for plant growth, nodulation, and grain yield underfield experiment. Under field conditions, Rhizobium sp and Pseudomonas koreensis were found best as singleinoculation by improving 53% and 49% grain yield, respectively. These potential bacteria could be used asbiofertilizers for soybean crop productivity.

Inhibition mechanism of atrazine on soybean growth insight from the plant nitrogen fixation and rhizobia diversity inhabiting in nodules and rhizosphere soil

Atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine] is a herbicide widely used in corn production. However, when used under corn-soybean rotation system, it decreases soybean yield. The toxicology mechanisms of atrazine on soybean are rarely studied from the perspective of rhizobia-soybean symbiont formation and nitrogen fixation. In this study, under atrazine stress, high-throughput sequencing of rpoB was performed to evaluate rhizobial diversity in the nodules and soybean rhizosphere, and the correlation between physiological indicators of plant growth and rhizobial diversity was explored. The results revealed that atrazine inhibited soybean growth by disrupting glutamate synthetase activity to reduce total nitrogen (TN) content in the plant. Atrazine altered the nodule structure and reduced leghemoglobin content. High-throughput sequencing of rpoB revealed that the inhibition rate of Afipia genosp. 3 in the nodules under atrazine stress (20 mg·kg−1) was >80 % higher than that in the control (no atrazine). The abundance of Rhizobium leguminosarum and Rhizobium sp. CF142 decreased in the nodules but increased in rhizosphere soil. The abundance of Afipia genosp. 3 and Bradyrhizobium sp. AD1_1_nodule in rhizosphere soil was negatively correlated with TN content and glutamate synthetase activity in soybean. Moreover, soil nitrate nitrogen (NO3−-N) content was the essential factor influencing the rhizobial community diversity under atrazine stress. This study contributed to clarifying the molecular biological mechanism of the effect of atrazine on rhizobia-soybean symbiont formation and nitrogen fixation. Moreover, this study provided new directions and ideas for the subsequent development and application of related prevention and control measures, which can contribute to the more comprehensive development of corn-soybean crop rotation system and ensure the sustainable use of black soil.

Plant growth promoting rhizobacteria exploration on butterfly pea (Clitoria ternatea l) from North Maluku Indonesia

The Plant Growth Promoting Rhizobacteria (PGPR) is associated with the roots and nodules of butterfly peas (Clitoria ternatea L.). This study aims to explore the PGPR in the rhizosphere of butterfly peas and to study their potential for biofertilizer. Characterization of PGPR was based on their ability to phosphate dissolution, auxin production, and nitrogen fixation as well as synergistic and antagonistic tests, and molecular identification. A total of 11 phosphate solubilizing bacteria isolates were isolated from the rhizosphere of butterfly peas while two isolates were taken from nodules. The RTF2 isolate from the rhizosphere had the highest phosphate solubility index. Meanwhile, the RTDH5-1, F1.1, and F2.1 showed strong inhibition ability against the growth of the pathogenic Rhizoctonia solani. The nitrogenase activity of isolates F2.1 and F1.1 from nodules were 0.975 μmol mL-1 g-1 h-1; while the IAA production was 7.87 and 7.05 mg L-1, respectively. The F1.1 had 100% similarity with Bacillus aryabhattai while F2.1 was 99.84% similar with Rhizobium sp. Both isolates can be used in biofertilizer formulation for North Maluku butterfly peas.

Effect of agronomic characteristics of hybrid and Creole corn using native plant growth-promoting bacteria to reduce the production cost

Objective: To design and to evaluate an environmentally-friendly biofertilizer based on plant growth-promoting bacteria (PGPB), assessing the agronomic characteristics of two genotypes of C/Acceleron A7573 hybrid and Creole corn. Design/methodology/approach: A biofertilizer based on PGPB was designed and assessed in a completely random experimental block design with nine treatments and four repetitions in C/Acceleron A7573 hybrid and Creole corn in a plot at El Pericón, municipality of Tecoanapa, Guerrero, Mexico. The microorganisms Rhizobium sp., A. brasilense and A. vinelandii were used. Results: The use of PGPB has greater effectiveness in all the agronomic variables and better yields because they are adapted to the environmental and soil conditions, with it being an excellent alternative to the use of fertilizers. Limitations on study/implications: The demonstrative experimental plot had 5000 m2 and it was the main limitation. Findings/conclusions: Bacteria of the genus A. brasilense YOM9 and A. vinelandii YOC4 contributed to the higher yield of the C/Acceleron A7573 hybrid corn seed, and Rhizobium sp R01 and A. vinelandii YOC4 in the Creole grain of the olotillo race compared to the T9 fertilizer and the absolute control. A biofertilizer for corn is obtained based on results from this study, as an ecotechnology based on PGPB

Effect of Rhizobium mechanisms in improving tolerance to saline stress in lettuce plants

BackgroundSoils affected by salinity are a recurring problem that is continually increasing due to the impact of climate change on weather conditions and ineffective agricultural management practices. The use of plant growth promoting (PGP) Bacteria can alleviate its effects. In this regard, the genus Rhizobium has demonstrated excellent PGP capabilities through various plant growth promotion mechanisms and may therefore be a promising biofortifier under saline conditions. However, little is known about the production of volatile organic compounds (VOCs) by bacteria of this genus and their effects on plant development. Here, we aim to characterize the volatilome (the set of volatile metabolites synthesized by an organism) of Rhizobium for the first time and to further investigate the direct and VOC-mediated interaction between a strain of this genus and lettuce, a crop severely affected by salinity, both under saline and non-saline conditions.ResultsIn this study, it was shown that the use of Rhizobium sp. GPTR29 was able to increase the production of lettuce (Lactuca sativa L.) under normal and saline conditions. We analyzed the Rhizobium volatilome under non-saline (0 mM NaCl) and saline (100 mM NaCl) conditions by HS-SPME-GC‒MS and found a differential composition in response to salinity. We detected 20 different compounds, where 3-methyl-1-butanol, 2-methyl-1-butanol, and α-pinene were the backbone of the Rhizobium volatilome. Exposure to these compounds in bicameral plates under salt stress resulted in increases in plant development of 17.1%, 16.0% and 33.1% in aerial part size, number of leaves and root length, respectively. Under greenhouse conditions and salinity, the inoculation of Rhizobium sp. GPTR29 resulted in an increase of 17.8% and 27.4% in shoot fresh and dry weight, respectively. Phenolic compounds were analyzed by HPLC–DAD-MS, revealing an increase in total flavonoid content under salinity conditions (100 mM NaCl) and apigenin derivative, luteolin 7-O-glucoside and quercetin 3-O-glucuronide individually.ConclusionsThese results provide new avenues for the study of PGP mechanisms in this bacterial genus, such as VOCs and their effects on plant growth, which play an important role in mediating plant–microorganism interactions.Graphical abstract

Growth and Production of Soybean (Glycine Max L.) Due to Urea Fertilization, Rhizobium sp. Inoculation and Phosphate Solubilizing Bacteria in Saline Soil

The study aimed to examine the dose of urea fertilizer, the inoculation dose of Rhizobium sp., and the doses of phosphate solubilizing bacteria, as well as the interaction between the two in soybean cultivation in saline soils. The study was carried out from July to November 2021 at the Ecology and Plant Production Laboratory, Greenhouse, and Chemical Analysis, Faculty of Animal and Agriculture, Diponegoro University, Semarang. A factorial 3 x 4 Completely Randomized Design (CRD) with 3 replications was the research methodology used. The dosage of urea fertilizer, with N0 = 100%, N1 = 90%, and N2 = 80%, is the first factor. The second factor is the dosage of Rhizobium sp. and phosphate-solubilizing bacteria that are inoculated, with P0 = No inoculum (control), P1 = 3 g/seed, P2 = 6 g/seed, and P3 = 9 g/seed. According to the research, it can be concluded that Rhizobium sp. and phosphate-solubilizing bacteria, along with urea fertilization, had a significant impact on plant height and early flowering but had no significant on the number of leaves and wet weight of pods generated in saline soil.

Effect of Boron Fertilizer and Double Inoculation of Rhizobium sp and Phosphate Solubilizing Bacteria on Soybean (Glycine Max L.) Growth and Production

Because of their high protein content, soybeans are a vital source of protein for human survival. By fertilizing with substances like biological fertilizers and micro fertilizers to meet the nutritional requirements of plants during growth, efforts can be made to increase the quality and quantity of soybean harvests.This research examines the effect of boron fertilizer and double inoculation doses, Rhizobium sp. and different Phosphate Solubilizing Bacteria (PSB) on soybean growth and production. A 3x4 factorial pattern with three replications and a completely randomized design (CRD) were used in this study. The first factor is the dosage of boron fertilizer (B) used, which has three treatment levels: B0 = 0 kg/ha (Control), B1 = (1 kg/ha), B2 (2 kg/ha), and B3 (3 kg/ha). The second factor is the double inoculation dose of PSB (R) and Rhizobium sp. with four treatment levels, namely R0 = control, R1 = 6 g/seed, and R2 = 12 g/seed. The findings demonstrated that the best pods, seed weight, and root nodules were produced by the double inoculation dose of Rhizobium sp. and PSB 12 g/seed. The production and growth of soybeans have not been impacted by boron fertilizer. On the other hand, the quantity of soybean seeds is impacted by the interaction of double inoculation doses of Rhizobium sp. and PSB with a dose of boron fertilizer.

PGPR-driven phytoremediation and physiobiochemical response of Miscanthus × giganteus to stress induced by the trace elements.

The effect of inoculation of Miscanthus × giganteus Greef et Deu by the plant growth promoting rhizobacteria (PGPRs) to the phytoremediation process and physio-biochemical plant's parameters was investigated in soil contaminated with the trace elements (TEs) from the Tekeli mining complex, Kazakhstan. Yeast Trichosporon sp. CA1, strains Rhizobium sp. Zn1-1, Shinella sp. Zn5-6, and Pseudomonas sp. CHA1-4, resistant to Zn and Pb, were isolated from the rhizosphere of M × g when the plant was cultivated in the same contaminated soil. Results illustrated that inoculation improved M × g adaptability to TEs toxicity by increasing the tolerance index to 2.9. The treatment enhanced the aboveground biomass yield by up to 163%, root biomass by up to 240%, chlorophyll content by up to 30%, and Chla/b ratio by up to 21%. Through M × g active growth and development, the peak activity of antioxidant enzymes was observed: activity of superoxide dismutase and glutathione reductase was induced, while the activity of catalase and ascorbate peroxidase was inhibited. Based on bioconcentration and translocation factors it was revealed that PGPRs selectively increased the uptake of TEs or stabilised them in the M × g rhizosphere. Inoculation with PGPRs increased the stabilization of Pb, V, Cr, Co, Ni, Cu, Cd, As, and Ba in the soil and plant tissues. Further research should focus on ex situ experiments using isolated PGPRs.

Silicate solubilizing and plant growth promoting bacteria interact with biogenic silica to impart heat stress tolerance in rice by modulating physiology and gene expression.

Heat stress caused due to increasing warming climate has become a severe threat to global food production including rice. Silicon plays a major role in improving growth and productivity of rice by aiding in alleviating heat stress in rice. Soil silicon is only sparingly available to the crops can be made available by silicate solubilizing and plant-growth-promoting bacteria that possess the capacity to solubilize insoluble silicates can increase the availability of soluble silicates in the soil. In addition, plant growth promoting bacteria are known to enhance the tolerance to abiotic stresses of plants, by affecting the biochemical and physiological characteristics of plants. The present study is intended to understand the role of beneficial bacteria viz. Rhizobium sp. IIRR N1 a silicate solublizer and Gluconacetobacter diazotrophicus, a plant growth promoting bacteria and their interaction with insoluble silicate sources on morpho-physiological and molecular attributes of rice (Oryza sativa L.) seedlings after exposure to heat stress in a controlled hydroponic system. Joint inoculation of silicates and both the bacteria increased silicon content in rice tissue, root and shoot biomass, significantly increased the antioxidant enzyme activities (viz. superoxidase dismutase, catalase and ascorbate peroxidase) compared to other treatments with sole application of either silicon or bacteria. The physiological traits (viz. chlorophyll content, relative water content) were also found to be significantly enhanced in presence of silicates and both the bacteria after exposure to heat stress conditions. Expression profiling of shoot and root tissues of rice seedlings revealed that seedlings grown in the presence of silicates and both the bacteria exhibited higher expression of heat shock proteins (HSPs viz., OsHsp90, OsHsp100 and 60 kDa chaperonin), hormone-related genes (OsIAA6) and silicon transporters (OsLsi1 and OsLsi2) as compared to seedlings treated with either silicates or with the bacteria alone. The results thus reveal the interactive effect of combined application of silicates along with bacteria Rhizobium sp. IIRR N1, G. diazotrophicus inoculation not only led to augmented silicon uptake by rice seedlings but also influenced the plant biomass and elicited higher expression of HSPs, hormone-related and silicon transporter genes leading to improved tolerance of seedling to heat stress.

Response of Bio-fertilizer and Phosphorus on Growth and Yield of Kabuli Chickpea (Cicer arietinum L. var. kabulium)

A field experiment entitled “Response of Bio-fertilizer and Phosphorus on growth and yield of Kabuli Chickpea (Cicer arietinum L. var. kabulium)” was conducted during rabi season, 2022-2023 at Crop Research Farm in the Department of agronomy, Naini Agriculture Institute, Sam Higginbottom University of Agriculture, Technology and Sciences, Prayagraj Uttar Pradesh. The soil texture of the experimental plot was sandy loam, with a pH of 7.1, low organic carbon (0.28 percent), available N (225 kg/ha), available P (19.50 kg/ha), and available K (213.7 kg/ha). The treatment consisted of three levels of Bio-fertilizer Rhizobium sp, PSB, Rhizobium sp and PSB in combination with Phosphorus (50, 60 and 70 kg/ha) and control. The experiment was layout in Randomized Block Design (RBD) with 10 treatments and replicated thrice. Application of (Rhizobium sp + PSB + Phosphorus 70 kg/ha) produces maximum plant height (57.67 cm), number of nodules/plant (47.80), dry weight (10.32 g), number of pods/plant (30.17), number of grains/pod (1.65) and seed yield (2975.44 kg/ha).

Response of Bio-fertilizer and Phosphorus on Yield and Economics of Kabuli Chickpea (Cicer arietinum L. var. kabulium)

At the Crop Research Farm, Department of Agronomy, SHUATS, Prayagraj, a field experiment was undertaken during the Rabi season 2022. The soil texture of the experimental plot was sandy loam, with a pH of 7.1, low organic carbon (0.28 percent), available N (225 kg/ha), available P (19.50 kg/ha), and available K (213.7 kg/ha). Rhizobium sp (20g/kg seed), PSB (20g/kg seed), and Rhizobium sp + PSB (10g/kg seed + 10g/kg seed) were used as bio-fertilizers, and phosphorus (50 kg P2O5/ha, 60kg P2O5/ha, 70 kg P2O5/ha) were used as fertilizers in 3 levels. The experiment used a Randomized Block Design with ten treatments and was repeated three times. The treatment of Rhizobium sp + PSB (10 g/kg seed + 10 g/kg seed) + Phosphorus (70 kg/ha) resulted in the highest plant height (57.67cm) (Treatment-10) recorded in the study. Number of nodules per plant (47.80), plant dry weight (10.32 g/plant), number of pods per plant (30.17), number of seeds per pod (1.65), seed yield (2975.44 kg/ha) and in treatment-8 [Rhizobium sp. + PSB + Phosphorus (50 kg/ha)] stover yield (4080.63 kg/ha) was recoded maximum, were all determined to be significant. The treatment (T10) with the application of Rhizobium sp + PSB (10g/kg seed + 10g/kg seed) + Phosphorus (70 kg/ha) produced the highest gross returns (157698.10 INR/ha), net returns (118348.64 INR/ha), and B:C ratio (3.01).