Effects of phosphorus-mobilizing bacteria on tomato growth and soil microbial activity

Abstract

Aims The aim of our study was to clarify whether inoculating a soil with Pseudomonas sp. RU47 (RU47) bacteria would stimulate the enzymatic cleavage of organic P compounds in the rhizosphere and bulk soil, promoting plant growth. Adding either viable or heat treated RU47 cells made it possible to separate direct from indirect effects of the inoculum on P cycling in soil and plants. Methods We performed a rhizobox experiment in the greenhouse with tomato plants (Solanum lycopersicum) under low P soil conditions. Three inoculation treatments were conducted, using unselectively grown soil bacteria (bacterial mix), heat treated (HT-RU47) and viable RU47 (RU47) cells, and one not inoculated, optimally P-fertilized treatment. We verified plant growth, nutrient availability, enzyme activities and microbial community structure in soil. Results A plant growth promotion effect with improved P uptake was observed in both RU47 treatments. Inoculations of RU47 cells increased microbial phosphatase activity (PA) in the rhizosphere. Conclusions Plant growth promotion by RU47 cells is primarily associated with increased microbial PA in soil, while promotion of indigenous Pseudomonads as well as phytohormonal effects appear to be the dominant mechanisms when adding HT-RU47 cells. Thus, using RU47 offers a promising approach for more efficient P fertilization in agriculture.

Response of phosphorus dynamics to sewage sludge application in an agroecosystem in northern France

“…Phosphorus concentrations were analysed colourimetrically (Murphy and Riley, 1962) using a spectrophotometer (712 nm). The ratio of recovered P to added P was used to calculate the P mic concentration as follows (Nassal et al, 2018):…”

Harnessing Soil Microbes to Improve Plant Phosphate Efficiency in Cropping Systems

“…There is a growing interest in using P solubilizing bacteria as biofertilizers to increase the bioavailability of P in soils used for crop production and to enhance the efficiency of P fertilizer applications ( Figure 1D). Increases in plant performance and/or yield after an inoculation with P-solubilizing bacteria have been shown for many agronomically important crop species, including corn [153], soybean [154], wheat [154,155], rapeseed [156], mung bean [157], and tomatoes [158]. While the periodic application of P fertilizer has adverse effects on the structure and function of phosphate-solubilizing bacterial communities, the opposite is true when little or no superphosphate is applied [159].…”

Growth Improvement of Tomato With the Application of Bacterial Isolates Producing Indole Acetic Acid (Iaa) and Phosphate Solubilizer

“…Researches with growth regulators and hormones associated with nutrient aim to accelerate the development of plants. The application of such elements in the early stages of plant development can stimulate root growth which would provide faster recovery after a period of water stress; greater resistance to pests, diseases and nematodes; and more rapid and uniform establishment of plants (Nassal et al 2018; du Jardin 2015; Zhao 2012; Bashan and de-Bashan 2010; Spaepen and Vanderleyden 2011).…”

“…It is reported that innoculation of Pseudomonas sp. RU49 in soil associated with the increased posphatase activity in the soil and improved tomato plant growth (Nassal et al 2018). The objectives of this study were to (1) evaluate the effectiveness of 19 microbial isolates which have P solubilizer and plant growth regulator characters in enhancing plant growth and yield of tomato (Palupi variety) grown in pots, and (2) molecularly identify the most effective isolates in improving tomato growth based on 16s rDNA sequences.…”