The use of 32P isotopic dilution techniques to evaluate the interactive effects of phosphate-solubilizing bacteria and mycorrhizal fungi at increasing plant P availability

Author(s):  
J. M. Barea ◽  
M. Toro ◽  
R. Azcón
2021 ◽  
Vol 12 ◽  
Author(s):  
Hassan Etesami ◽  
Byoung Ryong Jeong ◽  
Bernard R. Glick

Phosphorus (P) availability is usually low in soils around the globe. Most soils have a deficiency of available P; if they are not fertilized, they will not be able to satisfy the P requirement of plants. P fertilization is generally recommended to manage soil P deficiency; however, the low efficacy of P fertilizers in acidic and in calcareous soils restricts P availability. Moreover, the overuse of P fertilizers is a cause of significant environmental concerns. However, the use of arbuscular mycorrhizal fungi (AMF), phosphate–solubilizing bacteria (PSB), and the addition of silicon (Si) are effective and economical ways to improve the availability and efficacy of P. In this review the contributions of Si, PSB, and AMF in improving the P availability is discussed. Based on what is known about them, the combined strategy of using Si along with AMF and PSB may be highly useful in improving the P availability and as a result, its uptake by plants compared to using either of them alone. A better understanding how the two microorganism groups and Si interact is crucial to preserving soil fertility and improving the economic and environmental sustainability of crop production in P deficient soils. This review summarizes and discusses the current knowledge concerning the interactions among AMF, PSB, and Si in enhancing P availability and its uptake by plants in sustainable agriculture.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sabaiporn Nacoon ◽  
Sanun Jogloy ◽  
Nuntavun Riddech ◽  
Wiyada Mongkolthanaruk ◽  
Jindarat Ekprasert ◽  
...  

AbstractIn this work, the effects of co-inoculation between an arbuscular mycorrhizal fungus (AMF) and a phosphate solubilizing bacteria (PSB) to promote the growth and production of sunchoke under field condition were investigated during 2016 and 2017. Four treatments were set up as follows: plants without inoculation, with AMF inoculation, with PSB inoculation and with co-inoculation of PSB and AMF. The results showed the presence of PSB and AMF colonization at the harvest stage in both years. This suggested the survival of PSB and successful AMF colonization throughout the experiments. According to correlation analysis, PSB positively affected AMF spore density and colonization rate. Also, both AMF and PSB positively correlated with growth and production of sunchoke. Co-inoculation could enhance various plant parameters. However, better results in 2016 were found in co-inoculation treatment, while AMF inoculation performed the best in 2017. All of these results suggested that our AMF and PSB could effectively promote growth and production of sunchoke under field conditions. Such effects were varied due to different environmental conditions each year. Note that this is the first study showing successful co-inoculation of AMF and PSB for promoting growth and yield of sunchoke in the real cultivation fields.


2020 ◽  
Vol 5 (1) ◽  
pp. 300-304
Author(s):  
Betty Natalie Fitriatin ◽  
Dita Fauziah ◽  
Fabira Nur Fitriani ◽  
Dewi Nurma Ningtyas ◽  
Pujawati Suryatmana ◽  
...  

AbstractPhosphorus availability is the major constraint for plant growth in the acid soil ecosystem, due to high fixation by Al and Fe. Microbial fertilizers such as phosphate-solubilizing bacteria (PSB) can increase P availability in soils for root uptake. The objective of the research was to verify the ability of four isolates of PSB isolated from acid soil to solubilize unavailable inorganic phosphate, produce phosphatase, malic acid and indole acetic acid (IAA), as well as increase plant height of maize seedling. The bioassay by growing maize seedling in liquid nutrients has been performed to study the response of seedling to PSB inoculation. The experimental design of bioassay was a randomized block design with five replications. The results showed that the isolates RR 1 and SPR 4 had a relatively high solubilizing index. Moreover, all the PSB isolates had the ability to produce phosphatase and IAA and dissolve P. The performance of PSB-inoculated seedling was better visually and the root length was increased by 66.7–74.5% compared to the control. This result concludes that the species of four isolates needs to be identified by a biomolecular method and formulated as biofertilizers for increasing the maize productivity in the acid soil ecosystem.


Agronomy ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 127 ◽  
Author(s):  
Arjun Kafle ◽  
Kevin Cope ◽  
Rachel Raths ◽  
Jaya Krishna Yakha ◽  
Senthil Subramanian ◽  
...  

Phosphorus is an essential macronutrient required for plant growth and development. It is central to many biological processes, including nucleic acid synthesis, respiration, and enzymatic activity. However, the strong adsorption of phosphorus by minerals in the soil decreases its availability to plants, thus reducing the productivity of agricultural and forestry ecosystems. This has resulted in a complete dependence on non-renewable chemical fertilizers that are environmentally damaging. Alternative strategies must be identified and implemented to help crops acquire phosphorus more sustainably. In this review, we highlight recent advances in our understanding and utilization of soil microbes to both solubilize inorganic phosphate from insoluble forms and allocate it directly to crop plants. Specifically, we focus on arbuscular mycorrhizal fungi, ectomycorrhizal fungi, and phosphate-solubilizing bacteria. Each of these play a major role in natural and agroecosystems, and their use as bioinoculants is an increasing trend in agricultural practices.


Author(s):  
Zhikang Wang ◽  
Ziyun Chen ◽  
Xiangxiang Fu

The inoculation of beneficial microorganisms to improve plant growth and soil properties is a promising strategy in the soil amendment. However, the effects of co-inoculation with phosphate-solubilizing bacteria (PSB) and N2-fixing bacteria (NFB) on the soil properties of typical C-deficient soil remain unclear. Based on a controlled experiment and a pot experiment, we examined the effects of PSB (M: Bacillus megaterium and F: Pseudomonas fluorescens), NFB (C: Azotobacter chroococcum and B: Azospirillum brasilence), and combined PSB and NFB treatments on C, N, P availability, and enzyme activities in sterilized soil, as well as the growth of Cyclocarya Paliurus seedlings grow in unsterilized soil. During a 60-day culture, prominent increases in soil inorganic N and available P contents were detected after bacteria additions. Three patterns were observed for different additions according to the dynamic bacterial growth. Synergistic effects between NFB and PSB were obvious, co-inoculations with NFB enhanced the accumulation of available P. However, decreases in soil available P and N were observed on the 60th day, which was induced by the decreases in bacterial quantities under C deficiency. Besides, co-inoculations with PSB and NFB resulted in greater performance in plant growth promotion. Aimed at amending soil with a C supply shortage, combined PSB and NFB treatments are more appropriate for practical fertilization at intervals of 30–45 days. The results demonstrate that co-inoculations could have synergistic interactions during culture and application, which may help with understanding the possible mechanism of soil amendment driven by microorganisms under C deficiency, thereby providing an alternative option for amending such soil.


2010 ◽  
Vol 12 (3,4) ◽  
pp. 231 ◽  
Author(s):  
M. Ogut ◽  
F. Er ◽  
N. Kandemir

<p>Phosphate solubilizing bacteria can be used as soil or seed inoculum to increase soil phosphorus (P) availability for agricultural purposes. There is also a possibility of using these microorganisms to biotechnologically dissolve phosphate ores for the production of phosphorus fertilizers. Twenty-one soil samples were collected along a highway in Turkey to isolate phosphate solubilizing bacteria. A total of 20 phosphate solubilizers were isolated from the rhizosphere of wheat and maize grown in the pots, which contained the collected soil samples. The isolates were distributed among the genera, <em>Acinetobacter</em> (7), <em>Pseudomonas</em> (7), <em>Enterobacter</em> (2), <em>Enterococcus</em> (1), <em>Escherichia</em> (1), <em>Photorhabdus</em> (1), and <em>Bacillus</em> (1) as determined by the 16S rDNA gene sequence analysis. Since the <em>Acinetobacter</em> species were most effective in Pikovskaya’s agar, which contained tricalcium phosphate for the sole P-source, they were further experimented for the phosphate solubilization in batch cultures. The mean phosphorus dissolved in 5 day incubation ranged between 167 and 1022 ppm P. The initial pH of 7.8  dropped below 4.7 in six isolates with a gluconic acid production in the concentrations ranging between 27.5 and 37.5 mM. <em>Acinetobacter</em> isolates have some potential as an inoculum both for soil and biotechnological P-solubilization.</p>


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