How phosphorus-solubilizing bacteria <i>Cereibacter sphaeroides</i> changed the phosphorus uptake, growth, and yield of rice grown in salinized soils under greenhouse conditions

Phosphorus (P) is an important element in crop production. However, under climate change, salinization and acidification limit soil P availability and crop yield, especially rice, while the application of chemical P fertilizer causes an adverse effect on the environment. Thus, the study aimed at assessing the effectiveness of strains of purple nonsulfur bacteria (PNSB) that can solubilize P and tolerate salinity (PNSB-P) in reducing Na+ in soil and plant and improving P uptake, growth, and yield of rice in salinized soils in Vietnam. An experiment with two factors was arranged in completely randomized blocks and replicated four times under greenhouse conditions. Therein, the first factor was five levels of P fertilizers: 0 %, 25 %, 50 %, 75 %, and 100 % of the local recommended level. The second factor was the PNSB-P including single strains of <i>Cereibacter sphaeroides</i> ST16 and ST26, the mixed strains of both C. sphaeroides ST16 and ST26, and the negative control. The results showed that utilizing C. sphaeroides ST16 and ST26 decreased plant proline content by 2.46–6.70 µmol g<sup>-1</sup> and soil Na<sup>+</sup> concentration by 1.47–1.62 meq 100 g<sup>-1</sup>. Utilizing PNSB-P increased P content by 5.82–29.2 % in stem-leaf and 12.1–14.6 % in rice grain and decreased 15.1–16.4 % of Na content in stem-leaf and 8.00–15.1 % in rice grain. Moreover, utilizing PNSB-P improved soluble P content by 4.33–9.07 mg P kg<sup>-1</sup> and total P uptake by 24.0–46.6 % compared with the negative control. The <i>C. sphaeroides</i> bacteria not only increased rice yield components such as the number of panicles per pot, the number of rice grains per panicle, and filled rice grain rate but also enhanced 20.7–47.6 % of rice grain yield compared with the negative control. Noticeably, utilizing mixed bacterial strains decreased 100 % of chemical P fertilizer compared with the recommendation.