Stimulatory effect of phosphate-solubilizing bacteria on plant growth, stevioside and rebaudioside-A contents of Stevia rebaudiana Bertoni

• Published in: Applied soil ecology : a section of Agriculture, ecosystems & environment ecosystems & environment, 2010-10, Vol.46 (2), p.222-229
• Main Authors: Mamta, Rahi, Praveen, Pathania, Vijaylata, Gulati, Arvind, Singh, Bikram, Bhanwra, Ravinder Kumar, Tewari, Rupinder
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; Burkholderia gladioli; Chemical, physicochemical, biochemical and biological properties; Enterobacter aerogenes; fertilizer rates; fertilizers; Fundamental and applied biological sciences. Psychology; glycosides; indole acetic acid; microbial colonization; microbial genetics; nonnutritive sweeteners; nutrient availability; phosphate-solubilizing bacteria; Phosphate-solubilizing bacteria (PSB); phosphorus; Physics, chemistry, biochemistry and biology of agricultural and forest soils; phytochemicals; plant growth; Rebaudioside-A; rhizosphere bacteria; ribosomal RNA; roots; Serratia marcescens; siderophores; soil bacteria; soil fertility; Soil science; Stevia rebaudiana; Stevioside; tricalcium phosphate
• ISSN: 0929-1393; 1873-0272
• DOI: 10.1016/j.apsoil.2010.08.008

▶ Phosphate-solubilizing bacteria were isolated from the Stevia rhizosphere. ▶ Isolates belong to genera Burkholderia, Enterobacter and Serratia. ▶ Isolates enhanced the plant growth, stevioside and rebaudioside-A content. ▶ Stimulatory effect was observed on the soil and plant phosphorus content. ▶ Consortium treatment showed better results than individual treatments. The effect of four phosphate-solubilizing bacteria (PSB), ( Burkholderia gladioli 10216, Burkholderia gladioli 10217, Enterobacter aerogenes 10208 and Serratia marcescens 10238) as identified on the basis of 16S rRNA gene sequencing was evaluated on plant growth and commercially important glycosides, stevioside (ST) and rebaudioside-A (R-A) of Stevia rebaudiana in pots containing tricalcium phosphate (TCP) supplemented soil. The PSB were isolated from the rhizosphere of S. rebaudiana plants and tested for P-solubilization ability, biocompatibility, indole acetic acid (IAA) and siderophore production. In greenhouse study, treatment of either individual PSB or a consortium (of PSB) resulted in increased plant growth, ST and R-A contents. The stimulatory effect was observed with consortium treatment in plant growth parameters (shoot length, 22.5%; root length, 14.7%; leaf dry weight, 89.0%; stem dry weight, 76.3% and shoot biomass, 82.5%) and glycoside contents (ST, 150% plant −1 and R-A, 555% plant −1) as compared to the un-inoculated plants. Among individual PSB treatments, B. gladioli 10216 showed most promising response in majority of the parameters studied. The root colonization potential of PSB, assayed by RAPD technique, showed the colonization of all PSB isolates, though their extent of colonization varied.