scholarly journals Root-Derived Endophytic Diazotrophic Bacteria Pantoea cypripedii AF1 and Kosakonia arachidis EF1 Promote Nitrogen Assimilation and Growth in Sugarcane

2021 ◽  
Vol 12 ◽  
Author(s):  
Rajesh Kumar Singh ◽  
Pratiksha Singh ◽  
Dao-Jun Guo ◽  
Anjney Sharma ◽  
Dong-Ping Li ◽  
...  

Excessive, long-term application of chemical fertilizers in sugarcane crops disrupts soil microbial flora and causes environmental pollution and yield decline. The role of endophytic bacteria in improving crop production is now well-documented. In this study, we have isolated and identified several endophytic bacterial strains from the root tissues of five sugarcane species. Among them, eleven Gram-negative isolates were selected and screened for plant growth-promoting characteristics, i.e., production of siderophores, indole-3-acetic acid (IAA), ammonia, hydrogen cyanide (HCN), and hydrolytic enzymes, phosphorus solubilization, antifungal activity against plant pathogens, nitrogen-fixation, 1-aminocyclopropane-1-carboxylic acid deaminase activity, and improving tolerance to different abiotic stresses. These isolates had nifH (11 isolates), acdS (8 isolates), and HCN (11 isolates) genes involved in N-fixation, stress tolerance, and pathogen biocontrol, respectively. Two isolates Pantoea cypripedii AF1and Kosakonia arachidis EF1 were the most potent strains and they colonized and grew in sugarcane plants. Both strains readily colonized the leading Chinese sugarcane variety GT42 and significantly increased the activity of nitrogen assimilation enzymes (glutamine synthetase, NADH glutamate dehydrogenase, and nitrate reductase), chitinase, and endo-glucanase and the content of phytohormones gibberellic acid, indole-3-acetic acid, and abscisic acid. The gene expression analysis of GT42 inoculated with isolates of P. cypripedii AF1 or K. arachidis EF1 showed increased activity of nifH and nitrogen assimilation genes. Also, the inoculated diazotrophs significantly increased plant nitrogen content, which was corroborated by the 15N isotope dilution analysis. Collectively, these findings suggest that P. cypripedii and K. arachidis are beneficial endophytes that could be used as a biofertilizer to improve plant nitrogen nutrition and growth of sugarcane. To the best of our knowledge, this is the first report of sugarcane growth enhancement and nitrogen fixation by Gram-negative sugarcane root-associated endophytic bacteria P. cypripedii and K. arachidis. These strains have the potential to be utilized as sugarcane biofertilizers, thus reducing nitrogen fertilizer use and improving disease management.

Plants ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 761
Author(s):  
Sang-Mo Kang ◽  
Saqib Bilal ◽  
Raheem Shahzad ◽  
Yu-Na Kim ◽  
Chang-Wook Park ◽  
...  

Information on the use of endophytic bacteria as a bio-herbicide for the management of weed control in agricultural fields is limited. The current study aimed to isolate endophytic bacteria from evening primroses and to screen them for their bio-herbicidal activity. Two isolated endophytic bacteria (Pantoea dispersa YNA11 and Klebsiella pneumoniae YNA12) were initially screened for citrate utilization and for indole-3-acetic acid (IAA) and catalase production. The preliminary biochemical assessment showed YNA12 as a positive strain. Ammonia, catalase, and IAA in its culture filtrate were quantified. Gas Chromatography/Mass Spectroscopy- Selective Ion Monitoring (GC/MS-SIM) analysis revealed the production of IAA by YNA12 in a time-dependent manner. YNA12 also exhibited significant ammonia-producing potential and catalase activity against hydrogen peroxide. The YNA12 culture filtrate significantly inhibited the germination rate of evening primrose seeds, resulting in a marked reduction in seedling length and biomass compared with those of the control seeds. Moreover, the culture filtrate of YNA12 significantly accelerated the endogenous abscisic acid (ABA) production and catalase activity of evening primrose seedlings. Macronutrient regulation was adversely affected in the seedlings exposed to the culture filtrate of YNA12, leading to inhibition of seed germination. The current results suggest that endophytic YNA12 may be used as a potent bio-herbicidal agent for controlling weed growth and development.


ChemMedChem ◽  
2020 ◽  
Author(s):  
Melissa M. Cadelis ◽  
Steven A. Li ◽  
Marie‐Lise Bourguet‐Kondracki ◽  
Marine Blanchet ◽  
Hana Douafer ◽  
...  

2002 ◽  
Vol 92 (6) ◽  
pp. 590-596 ◽  
Author(s):  
Barry A. Cohen ◽  
Ziva Amsellem ◽  
Rudy Maor ◽  
Amir Sharon ◽  
Jonathan Gressel

Fusarium oxysporum and F. arthrosporioides, pathogenic on Orobanche aegyptiaca, were transformed with two genes of the indole-3-acetamide (IAM) pathway leading to indole-3-acetic acid (IAA) to attempt to enhance virulence. Transgenic F. oxysporum lines containing both the tryptophan-2-monooxyngenase (iaaM) and indole-3-acetamide hydrolase (iaaH) genes produced significantly more IAA than the wild type. IAM accumulated in culture extracts of F. oxysporum containing iaaM alone. F. arthrosporioides containing only iaaM accumulated IAM and an unidentified indole. Some transformants of F. oxysporum expressing only the iaaM gene also produced more IAA than the wild type. Sub-threshold levels (that barely infect Orobanche) of transgenic F. oxysporum expressing both genes and of F. arthrosporioides expressing iaaM were more effective in suppressing the number and size of Orobanche shoots than the wild type on tomato plants grown in soil mixed with Orobanche seed. Stimulating an auxin imbalance enhanced pathogen virulence by affecting the host in a manner similar to low doses of auxin herbicides such as 2,4-dichlorophenoxy acetic acid.


2018 ◽  
Author(s):  
Xiaohui Wang ◽  
Changdong Wang ◽  
Chao Ji ◽  
Qian Li ◽  
Jiamiao Zhang ◽  
...  

AbstractBacillus amyloliquefaciens subsp. plantarum XH-9 is a plant-beneficial rhizobacterium that shows good antagonistic potential against phytopathogens by releasing diffusible and volatile antibiotics, and secreting hydrolytic enzymes. Furthermore, the XH-9 strain possesses important plant growth-promoting characteristics, including nitrogen fixation (7.92 ± 1.05 mg/g), phosphate solubilization (58.67 ± 4.20 μg/L), potassium solubilization (10.07 ± 1.26 μg/mL), and the presence of siderophores (4.92 ± 0.46 μg/mL), indole-3-acetic acid (IAA) (7.76 ± 0.51 μg/mL) and 1-aminocyclopropane-1-carboxylic acid deaminase (ACC-deaminase) (4.67 ± 1.21 nmol/[mg•h]). Moreover, the XH-9 strain showed good capacities for wheat, corn, and chili root colonization, which are critical prerequisites for controlling soil-borne diseases as a bio-control agent. Real-time quantitative polymerase chain reaction experiments showed that the amount of Fusarium oxysporum DNA associated with the XH-9 strain after treatment significantly decreased compared with control group. Accordingly, wheat plants inoculated with the XH-9 strain showed significant increases in the plant shoot heights (14.20%), root lengths (32.25%), dry biomass levels (11.93%), and fresh biomass levels (16.28%) relative to the un-inoculated plants. The results obtained in this study suggest that the XH-9 strain has potential as plant-growth promoter and biocontrol agent when applied in local arable land to prevent damage caused by F. oxysporum and other phytopathogens.ImportancePlant diseases, particularly soilborne pathogens, play a significant role in the destruction of agricultural resources. Although these diseases can be controlled to some extent with crop and fungicides, while these measures increase the cost of production, promote resistance, and lead to environmental contamination, so they are being phased out. Plant growth-promoting rhizobacteria are an alternative to chemical pesticides that can play a key role in crop production by means of siderophore and indole-3-acetic acid production, antagonism to soilborne root pathogens, phosphate and potassium solubilization, and nitrogen fixation. These rhizobacteria can also promote a beneficial change in the microorganism community by significantly reducing its pathogenic fungi component. Their use is fully in accord with the principles of sustainability.


2004 ◽  
Vol 186 (16) ◽  
pp. 5384-5391 ◽  
Author(s):  
Sunhee Lee ◽  
M. Flores-Encarnación ◽  
M. Contreras-Zentella ◽  
L. Garcia-Flores ◽  
J. E. Escamilla ◽  
...  

ABSTRACT Gluconacetobacter diazotrophicus is an endophyte of sugarcane frequently found in plants grown in agricultural areas where nitrogen fertilizer input is low. Recent results from this laboratory, using mutant strains of G. diazotrophicus unable to fix nitrogen, suggested that there are two beneficial effects of G. diazotrophicus on sugarcane growth: one dependent and one not dependent on nitrogen fixation. A plant growth-promoting substance, such as indole-3-acetic acid (IAA), known to be produced by G. diazotrophicus, could be a nitrogen fixation-independent factor. One strain, MAd10, isolated by screening a library of Tn5 mutants, released only ∼6% of the amount of IAA excreted by the parent strain in liquid culture. The mutation causing the IAA− phenotype was not linked to Tn5. A pLAFR3 cosmid clone that complemented the IAA deficiency was isolated. Sequence analysis of a complementing subclone indicated the presence of genes involved in cytochrome c biogenesis (ccm, for cytochrome c maturation). The G. diazotrophicus ccm operon was sequenced; the individual ccm gene products were 37 to 52% identical to ccm gene products of Escherichia coli and equivalent cyc genes of Bradyrhizobium japonicum. Although several ccm mutant phenotypes have been described in the literature, there are no reports of ccm gene products being involved in IAA production. Spectral analysis, heme-associated peroxidase activities, and respiratory activities of the cell membranes revealed that the ccm genes of G. diazotrophicus are involved in cytochrome c biogenesis.


2020 ◽  
Vol 10 (1) ◽  
pp. 21
Author(s):  
Agustina Monalisa Tangapo

Potensi Bakteri Endofit Ubi Jalar (Ipomoea batatas L.) dalam Menghasilkan Hormon Indole Acetic Acid (IAA) dengan Penambahan L-triptofan(Potential of endophytic bacteria of sweet potato (Ipomoea batatas L.) in producing Indole Acetic Acid (IAA) with the addition of L-tryptophan) Agustina Monalisa TangapoProgram Studi Biologi FMIPA Universitas Sam RatulangiJl. Kampus Unsrat, Manado 95115*Email korespondensi:[email protected] (Article History: Received 5-01-2019; Revised 15-01-2020; Accepted 05-02-2020) ABSTRAKAsosiasi bakteri-tanaman, dapat mempengaruhi produktivitas tanaman secara langsung dan tidak langsung. Secara langsung, salah satunya yaitu bakteri dapat memproduksi dan menyekresikan zat pengatur tumbuh indole-3-acetic acid (IAA, auksin). Penelitian ini bertujuan untuk menguji kemampuan bakteri endofit ubi jalar dalam menghasilkan IAA. Metode analisis IAA dilakukan dengan metode kolorimetri. Analisis produksi IAA dilakukan dengan penambahan dan tanpa penambahan L-triptofan. Hasil penelitian menunjukkan bahwa tanpa penambahan L-triptofan, diperoleh sejumlah 19 jenis yang menghasilkan IAA dengan kisaran konsentrasi 0,29-7,21 mg/L. Dengan penambahan L-triptofan, jumlah jenis positif dan konsentrasi IAA yang dihasilkan meningkat signifikan. Jumlah jenis positif 20 jenis (91%) dan konsentrasi IAA yang dihasilkan mencapai kisaran 0,96-115,63 mg/L.Kata kunci: bakteri endofit; IAA; ubi jalar; L-triptofan ABSTRACTPlant-bacteria associations, can promote plant growth by both direct and indirect mechanisms. One of direct mechanisms is that bacteria can produce and secrete indole-3-acetic acid (IAA, auxin) growth regulators. This study aims to examine the ability of sweet potato endophytic bacteria to produce IAA. The detection of IAA production was conducted by colorimetric technique. IAA production analysis was carried out with addition and without addition of L-tryptophan. Without the addition of L-tryptophan, a total of 19 species produced IAA with a concentration range of 0.29-7.21 mg/L. With the addition of L-tryptophan, the number of positive species and the concentration of IAA produced increased significantly. The number of positive species was 20 species (91%) and the concentration of IAA produced reached a range of 0.96-115.63 mg/L.Keywords: endophytes bacterial; IAA; sweet potato; L-tryptophan


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