scholarly journals Profiling of Plant Growth-Promoting Metabolites by Phosphate-Solubilizing Bacteria in Maize Rhizosphere

Plants ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1071
Author(s):  
Minchong Shen ◽  
Jiangang Li ◽  
Yuanhua Dong ◽  
Hong Liu ◽  
Junwei Peng ◽  
...  

Microbial treatment has recently been attracting attention as a sustainable agricultural strategy addressing the current problems caused by unreasonable agricultural practices. However, the mechanism through which microbial inoculants promote plant growth is not well understood. In this study, two phosphate-solubilizing bacteria (PSB) were screened, and their growth-promoting abilities were explored. At day 7 (D7), the lengths of the root and sprout with three microbial treatments, M16, M44, and the combination of M16 and M44 (Com), were significantly greater than those with the non-microbial control, with mean values of 9.08 and 4.73, 7.15 and 4.83, and 13.98 and 5.68 cm, respectively. At day 14 (D14), M16, M44, and Com significantly increased not only the length of the root and sprout but also the underground and aboveground biomass. Differential metabolites were identified, and various amino acids, amino acid derivatives, and other plant growth-regulating molecules were significantly enhanced by the three microbial treatments. The profiling of key metabolites associated with plant growth in different microbial treatments showed consistent results with their performances in the germination experiment, which revealed the metabolic mechanism of plant growth-promoting processes mediated by screened PSB. This study provides a theoretical basis for the application of PSB in sustainable agriculture.

2021 ◽  
Vol 11 ◽  
Author(s):  
Jinge Xie ◽  
Zongqiang Yan ◽  
Guifen Wang ◽  
Wenzhi Xue ◽  
Cong Li ◽  
...  

Phosphorus in the soil accessible to plants can easily be combined with calcium ion, the content of which is high in karst rocky desertification (KRD) regions, thereby resulting in a low utilization efficiency of phosphorus. The application of phosphate-solubilizing bacteria (PSB) from the KRD region would facilitate enhanced phosphate availability in the soil. In the present study, the strains belonging to Acinetobacter, Paraburkholderia, and Pseudomonas with efficient phosphate-solubilizing ability were isolated from fruit tree rhizosphere soils in KRD regions. Particularly, Acinetobacter sp. Ac-14 had a sustained and stable phosphate-solubilizing ability (439–448 mg/L, 48–120 h). Calcium carbonate decreased the phosphate-solubilizing ability in liquid medium; however, it did not affect the solubilization index in agar-solidified medium. When cocultivated with Arabidopsis thaliana seedling, Ac-14 increased the number of lateral roots, fresh weight, and chlorophyll content of the seedlings. Metabolomics analysis revealed that Ac-14 could produce 23 types of organic acids, majorly including gluconic acid and D-(-)-quinic acid. Expression of Ac-14 glucose dehydrogenase gene (gcd) conferred Pseudomonas sp. Ps-12 with a sustained and stable phosphate-solubilizing ability, suggesting that the production of gluconic acid is an important mechanism that confers phosphate solubilization in bacteria. Moreover, Ac-14 could also produce indole acetic acid and ammonia. Collectively, the isolated Ac-14 from KRD regions possess an efficient phosphate-solubilizing ability and plant growth-promoting effect which could be exploited for enhancing phosphorus availability in KRD regions. This study holds significance for the improvement of soil fertility and agricultural sustainable development in phosphorus-deficient KRD regions.


2007 ◽  
Vol 2 (3) ◽  
pp. 326-333 ◽  
Author(s):  
A. Vikram ◽  
H. Hamzehzarghani . ◽  
A.R. Alagawadi . ◽  
P.U. Krishnaraj . ◽  
B.S. Chandrashekar .

2021 ◽  
Vol 57 (No. 2) ◽  
pp. 95-111
Author(s):  
Olubukola Babalola ◽  
Oluwaseun Adeyinka Fasusi

Agricultural practices depend mainly on the use of chemical fertilisers, pesticides, and herbicides which have caused serious health hazards and have also contributed to the pollution of the environment at large. The application of plant-beneficial rhizobacteria in agrarian practices has become paramount in increasing soil fertility, promoting plant growth, ensuring food safety, and increasing crop production to ensure sustainable agriculture. Beneficial rhizobacteria are soil microorganisms that are eco-friendly and serve as a modern method of improving the plant yield, protecting the plant and soil fertility that pose no harm to humans and the environment. This eco-friendly approach requires the application of beneficial rhizobacteria with plant growth-promoting traits that can improve the nutrient uptake, enhance the resistance of plants to abiotic and biotic stress, protect plants against pathogenic microorganisms and promote plant growth and yield. This review article has highlighted the multitasking roles that beneficial rhizobacteria employ in promoting plant growth, food production, bioremediation, providing defence to plants, and maintaining soil fertility. The knowledge acquired from this review will help in understanding the bases and importance of plant-beneficial rhizobacteria in ensuring agricultural sustainability and as an alternative to the use of agrochemicals.


2016 ◽  
Author(s):  
Anuradha Rai ◽  
Pradeep K Rai ◽  
Jay S Singh ◽  
Surendra Singh

Medicinal plants provide an enormous bioresource of potential use in modern medicine and agriculture. Phosphorous deficiency is a major constraint to plant production. Sustainable agriculture could be promoted by harnessing the plant beneficial bacteria particularly the fluorescent pseudomonads associated with the rhizosphere of plants, to mobilize soil inorganic phosphate and also to increase its bioavailability to the plants. Total five hundred seven fluorescent Pseudomonas isolates were obtained from four different Aloe barbadensis (Miller) growing locations of Varanasi. These Pseudomonas strains were further evaluated in vitro for their ability to solubilize phosphate and to produce indole acetic acid (IAA), hydrogen cyanide (HCN), siderophore and aminocyclopropane (ACC) deaminase. Total 119 fluorescent Pseudomonas isolates from the rhizospheric soil (RS) and 25 isolates from the endorhizosperic (ER) region solubilized phosphate.Whereas 53 (36.8%) Pseudomonas isolates produced IAA and siderophore, 36(25%) and 31 (21.5%) isolates, however, produced HCN and ACC deaminase. Out of 119 phosphate solubilizing bacteria (PSB) from RS region, 51 (42.9%) isolates and 9 (36%) isolates out of 25 PSBs from ER region lacked plant growth promoting traits (PGPTs). Among the phosphate solubilizing fluorescent pseudomonads showing PGPT, 59 isolates have multiple traits and showed more than two types of PGPT. A positive correlation exists between siderophore and ACC deaminase producers. Clustering by principal component analysis (PCA) showed that RS was the most important factor influencing the ecological distribution and physiological characterization of PGPT- possessing PSB. Geographical Information System (GIS) and Kriging Interpolation method was used to map and establish spatial variation of soil properties of the study site.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jiaqi Chen ◽  
Guangyu Zhao ◽  
Yihui Wei ◽  
Yuhong Dong ◽  
Lingyu Hou ◽  
...  

AbstractPhosphorus-solubilizing microorganisms is a microbial fertilizer with broad application potential. In this study, 7 endophytic phosphate solubilizing bacteria were screened out from Chinese fir, and were characterized for plant growth-promoting traits. Based on morphological and 16S rRNA sequence analysis, the endophytes were distributed into 5 genera of which belong to Pseudomonas, Burkholderia, Paraburkholderia, Novosphingobium, and Ochrobactrum. HRP2, SSP2 and JRP22 were selected based on their plant growth-promoting traits for evaluation of Chinese fir growth enhancement. The growth parameters of Chinese fir seedlings after inoculation were significantly greater than those of the uninoculated control group. The results showed that PSBs HRP2, SSP2 and JRP22 increased plant height (up to 1.26 times), stem diameter (up to 40.69%) and the biomass of roots, stems and leaves (up to 21.28%, 29.09% and 20.78%) compared to the control. Total N (TN), total P (TP), total K (TK), Mg and Fe contents in leaf were positively affected by PSBs while showed a significant relationship with strain and dilution ratio. The content of TN, TP, TK, available phosphorus (AP) and available potassium (AK) in the soil increased by 0.23–1.12 mg g−1, 0.14–0.26 mg g−1, 0.33–1.92 mg g−1, 5.31–20.56 mg kg−1, 15.37–54.68 mg kg−1, respectively. Treatment with both HRP2, SSP2 and JRP22 increased leaf and root biomass as well as their N, P, K uptake by affecting soil urease and acid phosphatase activities, and the content of available nutrients in soil. In conclusion, PSB could be used as biological agents instead of chemical fertilizers for agroforestry production to reduce environmental pollution and increase the yield of Chinese fir.


Agriculture ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 316
Author(s):  
Nidal Fahsi ◽  
Ismail Mahdi ◽  
Abdelhalem Mesfioui ◽  
Latefa Biskri ◽  
Abdelmounaaim Allaoui

In recent years, the low Zn content of wheat has become critical. Consequently, solutions that can improve the Zn nutrition of wheat are highly researched. In the present investigation, we aimed to evaluate the potential benefits of phosphate-solubilizing bacteria isolated from Ziziphus lotus on wheat seedling growth. Based on the phosphate-solubilizing criteria, four isolated strains, J16, J143, J146, and J158, were identified by 16SrRNA gene sequencing as Pseudomonas moraviensis, Bacillus halotolerans, Enterobacter hormaechei, and Pseudomonas frederiksbergensis, respectively. Studies of the conventional properties of plant growth-promoting rhizobacteria (PGPR) showed that E. hormaechei J146 produced up to 550 mg·L−1 of indole-3-acetic acid (IAA). Siderophores and ammonia were produced by all strains but cellulase was restricted to B. halotolerans J143, whereas proteases were missing in E. hormaechei J146 and P. frederiksbergensis J158. E. hormaechei J146 tolerate up to 1.5 mg·L−1 of copper and cadmium, while B. halotolerans J143 withstood 1.5 mg·L−1 of nickel. Strains B. halotolerant J143, E. hormaechei J146, and P. frederiksbergensis J158 remarkably improved wheat seed germination, plant growth, and Zn absorption. Lastly, nutrient measurement revealed that a wheat plant inoculated with E. hormaechei J146 and P. frederiksbergensis J158 increased its nitrogen and potassium uptake by up to 17%.


2020 ◽  
Vol 8 (6) ◽  
pp. 948
Author(s):  
Ismail Mahdi ◽  
Nidal Fahsi ◽  
Mohamed Hafidi ◽  
Abdelmounaaim Allaoui ◽  
Latefa Biskri

Plant growth-promoting rhizobacteria represent a promising solution to enhancing agricultural productivity. Here, we screened phosphate solubilizing bacteria from the rhizospheric soil of Chenopodium quinoa Willd and assessed their plant-growth promoting rhizobacteria (PGPR) properties including production of indole-3-acetic acid (IAA), siderophores, hydrogen cyanide (HCN), ammonia and extracellular enzymes. We also investigated their tolerance to salt stress and their capacity to form biofilms. Two isolated strains, named QA1 and QF11, solubilized phosphate up to 346 mg/L, produced IAA up to 795.31 µg/mL, and tolerated up to 2 M NaCl in vitro. 16S rRNA and Cpn60 gene sequencing revealed that QA1 and QF11 belong to the genus Bacillus licheniformis and Enterobacter asburiae, respectively. In vivo, early plant growth potential showed that quinoa seeds inoculated either with QA1 or QF11 displayed higher germination rates and increased seedling growth. Under saline irrigation conditions, QA1 enhanced plant development/growth. Inoculation with QA1 increased leaf chlorophyll content index, enhanced P and K+ uptake and decreased plant Na+ uptake. Likewise, plants inoculated with QF11 strain accumulated more K+ and had reduced Na+ content. Collectively, our findings support the use of QA1 and QF11 as potential biofertilizers.


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