Co-cultivation of wheat and Arabidopsis thaliana with nitrogen-fixing cyanobacteria: a strategy to enhance plant growth and drought tolerance

Abstract A growing world population is presenting the agricultural industry with increasing challenges. While a growing population needs to be fed, climate change means that agriculture must become more sustainable and tolerant against extreme events such as drought. Cyanobacteria are promising biofertilizers due to their nitrogen-fixing ability and biofilm formation. Therefore, the growth-promoting effect of nitrogen-fixing cyanobacteria ( Anabaena cylindrica , Nostoc calcicola , and Nostoc muscorum ) on wheat ( Triticum aestivum ) as a widely cultivated crop plant, was investigated in this study, both in hydroponic and pot culture experiments. Co-cultures of living N. calcicola with wheat were investigated for the first time in this study and showed the greatest growth-promoting effect, resulting in a significantly higher dry mass of the plants in hydroponics (+ 30%) compared to the control. In pot culture, the dry mass was increased by 44% with N. calcicola . The seedling length of the wheat plants was most strongly stimulated by co-cultivation with A. cylindrica . Co-cultures with the model plant Arabidopsis thaliana were carried out with and without the induction of drought stress. A significant increase in the dry mass of A. thaliana was achieved by co-cultivation with N. calcicola (+ 83%) without drought stress. The growth of A. thaliana was also stimulated under drought stress. Treatment with N. muscorum and N. calcicola resulted in the greatest improvement in DW, at 57% and 32%, respectively. This study highlights cyanobacteria as an effective biofertilizer that enhances plant growth and stress tolerance, reducing the need for synthetic fertilizers.