Abstract The use of rhizobacteria associated with plant roots in extreme environments could be a promising strategy to overcome the limitations of crop production induced by soil salinity. In the present study, we isolated phosphate solubilizing bacteria from the rhizosphere of Tamarix ramosissima which is common native plants grown on a saline-alkaline site, to investigate the ability of these bacteria to alleviate salt stress in common bean (Phaseolus vulgaris cv. Karnac) plants. Among 5 isolates could solubilize phosphate, we selected the two most efficiency isolates No. 4 (AL-18) and No. 2 (AL-19). The partial sequence of 16S rDNA genes and phylogenetic tree indicated that AL-18 and AL-19 related to Bacillus megaterium and Bacillus cereus respectively. B. megaterium AL-18 and B. cereus AL-19 could survive and solubilize inorganic phosphate up to 14% NaCl. Maximum solubilization of tri-calcium phosphate (TCP) by both strains was observed at 6% NaCl and pH 7. The effect of selected strains on common bean growth under salt stress was conducted in pots experiments under greenhouse condition. Growth parameters including root length, plant height, root and shoot dry weight, phosphate content in plants and photosynthetic pigments were significantly increased by single and dual inoculation of the two selected strains under salt stress conditions. In conclusion, our results showed that inoculation of Phaseolus vulgaris with B. megaterium AL-18, B. cereus AL-19 isolated from the rhizosphere of Tamarix ramosissima, can alleviate the deleterious effects of salinity and improve plant growth, phosphate uptake and photosynthetic pigments under salt stress conditions, which were demonstrated in vivo. However, field experiments under natural conditions are needed to study the mechanisms by which the identified strains induce salinity tolerance in plants.

中文翻译：

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溶磷芽孢杆菌的分离鉴定 柽柳根际及其对盐胁迫下菜豆生长的影响

摘要 在极端环境中使用与植物根系相关的根际细菌可能是克服土壤盐分引起的作物生产限制的有前途的策略。在本研究中，我们从生长在盐碱地的常见原生植物柽柳根际分离磷酸盐溶解细菌，以研究这些细菌减轻普通豆（Phaseolus vulgaris cv. Karnac）盐胁迫的能力植物。在可以溶解磷酸盐的5个分离株中，我们选择了两个最有效的分离株4号（AL-18）和2号（AL-19）。16S rDNA基因部分序列和系统发育树表明AL-18和AL-19分别与巨大芽孢杆菌和蜡样芽孢杆菌相关。B. megaterium AL-18 和 B. 蜡状 AL-19 可以存活并溶解高达 14% NaCl 的无机磷酸盐。在 6% NaCl 和 pH 7 下观察到两种菌株对磷酸三钙 (TCP) 的最大增溶作用。在温室条件下的盆栽试验中，对选定菌株在盐胁迫下对普通豆生长的影响进行了研究。在盐胁迫条件下，通过单一和双重接种两种选定菌株，生长参数包括根长、株高、根和枝条干重、植物中的磷酸盐含量和光合色素显着增加。总之，我们的结果表明，用从柽柳根际分离的巨大芽孢杆菌 AL-18、蜡状芽孢杆菌 AL-19 接种菜豆，可以减轻盐分的有害影响并促进植物生长，盐胁迫条件下的磷酸盐吸收和光合色素，这在体内得到了证明。然而，需要在自然条件下进行田间试验来研究已鉴定菌株诱导植物耐盐性的机制。