scholarly journals Metagenomic Analyses of Plant Growth-Promoting and Carbon-Cycling Genes in Maize Rhizosphere Soils with Distinct Land-Use and Management Histories

Genes ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1431
Author(s):  
Chinenyenwa Chukwuneme ◽  
Ayansina Ayangbenro ◽  
Olubukola Babalola
Keyword(s):  
Land Use ◽  
Plant Growth ◽  
Carbon Cycling ◽  
Shotgun Metagenomics ◽  
Maize Rhizosphere ◽  
Rhizosphere Soils ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
Microbial Genes ◽  
Land Use And Management

Many studies have shown that the maize rhizosphere comprises several plant growth-promoting microbes, but there is little or no study on the effects of land-use and management histories on microbial functional gene diversity in the maize rhizosphere soils in Africa. Analyzing microbial genes in the rhizosphere of plants, especially those associated with plant growth promotion and carbon cycling, is important for improving soil fertility and crop productivity. Here, we provide a comparative analysis of microbial genes present in the rhizosphere samples of two maize fields with different agricultural histories using shotgun metagenomics. Genes involved in the nutrient mobilization, including nifA, fixJ, norB, pstA, kefA and B, and ktrB were significantly more abundant (α = 0.05) in former grassland (F1) rhizosphere soils. Among the carbon-cycling genes, the abundance of 12 genes, including all those involved in the degradation of methane were more significant (α = 0.05) in the F1 soils, whereas only five genes were significantly more abundant in the F2 soils. α-diversity indices were different across the samples and significant differences were observed in the β diversity of plant growth-promoting and carbon-cycling genes between the fields (ANOSIM, p = 0.01 and R = 0.52). Nitrate-nitrogen (N-NO3) was the most influential physicochemical parameter (p = 0.05 and contribution = 31.3%) that affected the distribution of the functional genes across the samples. The results indicate that land-use and management histories impact the composition and diversity of plant growth-promoting and carbon-cycling genes in the plant rhizosphere. The study widens our understanding of the effects of anthropogenic activities on plant health and major biogeochemical processes in soils.

scholarly journals Pseudomonas PS01 Isolated from Maize Rhizosphere Alters Root System Architecture and Promotes Plant Growth

2020 ◽  
Vol 8 (4) ◽  
pp. 471 ◽  
Author(s):  
Thanh Nguyen Chu ◽  
Le Van Bui ◽  
Minh Thi Thanh Hoang
Keyword(s):  
Plant Growth ◽  
Root System ◽  
System Architecture ◽  
High Throughput Sequencing ◽  
Primary Root ◽  
Root System Architecture ◽  
Potential Candidate ◽  
Maize Rhizosphere ◽  
Plant Growth Promoting ◽  
Growth Promoting

The objectives of this study were to evaluate the plant growth promoting effects on Arabidopsis by Pseudomonas sp. strains associated with rhizosphere of crop plants grown in Mekong Delta, Vietnam. Out of all the screened isolates, Pseudomonas PS01 isolated from maize rhizosphere showed the most prominent plant growth promoting effects on Arabidopsis and maize (Zea mays). We also found that PS01 altered root system architecture (RSA). The full genome of PS01 was resolved using high-throughput sequencing. Phylogenetic analysis identified PS01 as a member of the Pseudomonas putida subclade, which is closely related to Pseudomonas taiwanensis.. PS01 genome size is 5.3 Mb, assembled in 71 scaffolds comprising of 4820 putative coding sequence. PS01 encodes genes for the indole-3-acetic acid (IAA), acetoin and 2,3-butanediol biosynthesis pathways. PS01 promoted the growth of Arabidopsis and altered the root system architecture by inhibiting primary root elongation and promoting lateral root and root hair formation. By employing gene expression analysis, genetic screening and pharmacological approaches, we suggested that the plant-growth promoting effects of PS01 and the alteration of RSA might be independent of bacterial auxin and could be caused by a combination of different diffusible compounds and volatile organic compounds (VOCs). Taken together, our results suggest that PS01 is a potential candidate to be used as bio-fertilizer agent for enhancing plant growth.

Analysis of plant growth promoting rhizobacteria population in apple rhizosphere soils

2012 ◽  
Vol 19 (6) ◽  
pp. 1372-1378
Author(s):  
Hui GUO ◽  
Zhi-Quan MAO ◽  
Zhen SONG ◽  
Ben-Feng ZHANG ◽  
Nian-Quan QIU ◽  
...  
Keyword(s):  
Plant Growth ◽  
Plant Growth Promoting Rhizobacteria ◽  
Rhizosphere Soils ◽  
Plant Growth Promoting ◽  
Growth Promoting

scholarly journals Biochemical and Molecular Characterization, and Bioprospecting of Drought Tolerant Actinomycetes from Maize Rhizosphere Soil

2020 ◽  
Author(s):  
Chinenyenwa Fortune Chukwuneme ◽  
Olubukola Oluranti Babalola ◽  
Funso Raphael Kutu ◽  
Omena Bernard Ojuederie
Keyword(s):  
Drought Tolerance ◽  
Plant Growth ◽  
Rna Binding ◽  
Binding Protein ◽  
Rrna Gene ◽  
Maize Rhizosphere ◽  
Siderophore Biosynthesis ◽  
Drought Tolerant ◽  
Plant Growth Promoting ◽  
Growth Promoting

AbstractDrought is a major limitation to maize cultivation around the globe. Seven actinomycetes strains were isolated from maize rhizosphere soils in Mahikeng, North-West Province, South Africa. The isolates were biochemically characterized and identified with 16S rRNA gene sequence analysis. Isolates were also screened in vitro for abiotic stress tolerance to different concentrations of NaCl, pH, and polyethylene glycol (PEG 8000), as well as for biosynthesis of drought tolerance genes namely Glutathione peroxidase (GPX), Glycine-rich RNA binding protein (GRP), Desiccation protectant protein (DSP), Guanosine triphosphate binding protein (GTP) and plant growth-promoting genes:1-aminocyclopropane-1-carboxylate deaminase (accd) and siderophore biosynthesis (Sid). About 71.43% of isolates were of the genus Streptomyces (99-100% similarity), while 14.29% belong to the genus Arthrobacter (R15) and 14.29% to the genus Microbacterium (S11) respectively (99% similarity). Five isolates had their optimum growth at 35°C. Arthrobacter arilaitensis (R15) grew and tolerated 5%, 10%, and 20% PEG at 120 h. Root length increased by 110.53% in PEG treated maize seeds (−0.30 MPa) inoculated with Streptomyces pseudovenezuelae (S20) compared to the un-inoculated control. Likewise, germination percentage and vigor index increased by 37.53% and 194.81% respectively in PEG treated seeds inoculated with S20 than the un-inoculated PEG treated seeds. ACC deaminase gene was amplified in all the isolates, while the gene for siderophore biosynthesis was amplified in 85.71% of the isolates. Genes for the synthesis of GPX, GRP, DSP and GTP were amplified in Arthrobacter arilaitensis (R15) and Streptomyces pseudovenezuelae (S20) which lacked GTP. The amplification of drought-tolerant and plant growth-promoting primers indicates the possible presence of these genes in the isolates. These isolates have the potential for use as bio-inoculants, not only to improve drought tolerance in maize but also to be utilized as biofertilizers and biocontrol agents to facilitate growth promotion.

scholarly journals Plant growth promoting actinobacteria from rhizosphere soils of black pepper in Wayanad

2021 ◽  
Vol 2 (5) ◽  
pp. 01-08
Author(s):  
Rineesha backera
Keyword(s):  
Nitrogen Fixation ◽  
Plant Growth ◽  
Biochemical Characterization ◽  
Black Pepper ◽  
Soil Samples ◽  
Root Weight ◽  
Rhizosphere Soils ◽  
Iaa Production ◽  
Plant Growth Promoting ◽  
Growth Promoting

Actinobacteria isolated from the rhizosphere soils of black pepper comprising both flood affected and non-flood affected areas of Wayanad district. Among different soil samples analysed, Puttad (Ptd) recorded significantly superior actinobacterial population on starch casein aga, Kenknight & Munaier’s agar and actinomycetes isolation agar. Actinobacterial colonies could not be detected in any of the flooded soil samples on any medium, even at a dilution of 10-1, except in Meppadi soil, which recorded a low population of 0.3x101cfu g-1 soil. Starch casein agar is best media to isolate actinobacteria from soil samples compared to other two media. The cultural, morphological and biochemical characterization of thirty-five isolates was carried out. Further the isolates were evaluated for their plant growth promoting traits such as IAA production, nitrogen fixation, P, K and Zn solubilization. The isolates Ptd-A and Amb-C were found to be significantly superior to all other isolates, with IAA production of 15.9 g ml-1 and 15.38 g ml-1 respectively. The four isolates viz. Ptd-A, Ptd-E, Ptd-B and Ptr-A recorded significantly superior nitrogen fixation and the phosphate solubilized was significantly higher in Ptd-E, Ptd-D, Ptr-E, Ptd-A and Ptr-A, as compared to other isolates. All isolates were negative to K and Zn solubilization. Based on in vitro evaluations, three isolates were shortlisted (Ptd-A, Ptd-E and Ptr-A) and subjected to in vivo evaluation for growth promotion in black pepper (variety Panniyur 1). Rooted plants of black pepper were raised in sterile potting mixture. Bioinoculants applied at the time of planting and 45 days after planting. The PGPR Mix-1 and Organic Package of Practices Recommendations (2017) were used for comparison with the microbial inoculants along with control. In the in-planta experiment, biometric characters were recorded at monthly intervals, up to five months. The actinobacterial treatment, T1: Ptd-E, T2: Ptd-A and T3: Ptr-A showed significant increase in shoot length, number of leaves and internode length throughout the growth period from planting to five MAP. Significantly higher root growth was observed in treatment T2: Ptd-A, with significantly higher root volume, fresh and root weight. The potential actinobacteria were identified Ptd-A and Ptr-A as Streptomyces sp. and Ptd-A as Actinobacteria bacterium using 16S r RNA gene sequencing.

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