In vitro rhizobia response and symbiosis process under Aluminum stress

Aluminium (Al) toxicity is a major problem affecting soil fertility, microbial diversity, and nutrients uptake of plants. Rhizobia response and legume-interaction under Al conditions are still unknown and it is important to understand how to develop and improve legume cultivation under Al-stress. In this study, rhizobia-response was recorded under different Al-concentrations. Al-effect on rhizobial cells was characterized by combination with different two pH conditions. Symbiosis process was compared between ι- and β-rhizobia inoculated onto soybean varieties. Rhizobial cell numbers was decreased as Al concentration increased. However, induced Al-tolerance considerably depended on rhizobia types and their origins. Accordingly, organic acid results were in correlation with growth rate and cell density which suggested that citric acid might be a positive selective force for Al-tolerance and plant-interaction on rhizobia. Al-toxicity delayed and interrupted the plant-rhizobia interaction and the effect was more pronounced under acidic conditions. Burkholderia fungorum VTr35 significantly improved plant growth under acid-Al stress in combination with all soybean varieties. Moreover, plant genotype was an important factor to establish an effective nodulation and nitrogen fixation under Al-stress. Additionally, tolerant-rhizobia could be applied as an inoculant on stressful agroecosystems. Furthermore, metabolic pathways have still been unknown under Al-stress.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author