Biotechnological potential of growth-promoting bacteria in cotton (Gossypium hirsutum L.) crop

Studies involving plant growth -promoting bacteria are attracting increasing attention in the agricultural sector due to their potential to improve growth and production, and to protect plants from biotic and abiotic stresses. The present study aimed to evaluate the effects of three species of plant growth -promoting bacteria ( Bacillus subtilis , Priestia megaterium, and Priestia aryabhattai ) on the growth and morphological and biochemical aspects of Gossypium hirsutum L. (cotton) seedlings. The experiment was conducted in a greenhouse with four treatments (one control and three inoculations) and five replications per treatment. The seeds were inoculated by immersion in bacterial suspensions (10 9 CFU/mL) and then sown in pots. The plants were monitored for 60 days. During collection, the plants were measured for the fresh mass of roots and shoots, the height of the shoots, stem diameter, and number of leaves. Leaf samples were collected and used for biochemical analyses. The results obtained showed that seeds treated with P. aryabhattai had significant improvements in the parameters of fresh mass, plant height, stem diameter, and number of leaves, and in the contents of chlorophyll ( a , b, and total), nitrogen, and proteins concerning plants in the control treatment. Plants treated with P. megaterium also achieved improvements in fresh mass, stem diameter, nitrogen, and protein contents. These results indicate the potential of these plant growthpromoting bacteria for use in cotton crops and can be employed in the preparation of biostimulants and biofertilizers.