ACC Deaminase-Containing Rhizobacteria from Rhizosphere of Zygophyllum coccineum Alleviate Salt Stress Impact on Wheat (Triticum aestivum L.)

Abstract

Plant growth-promoting bacteria are present in the rhizosphere, a soil zone around plant roots. An important mechanism of plant growth enhancement is the production of 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase. Three ACC deaminase-producing bacterial strains were isolated from the rhizosphere of the halophytic plant Zygophyllum coccineum growing in Al-Uqair, Al-Ahsa Saudi Arabia. The strains were identified as Bacillus filamentosus, Janibacter indicus, and Brevibacterium casei based on 16S rRNA sequence, and their taxonomic position was determined. Furthermore, the strains exhibited catalase and indoleacetic acid production and phosphate solubilization. The highest ACC deaminase activity was observed in B. filamentosus (~ 449 nmole α- ketobutyrate mg-1 h-1), followed by J. indicus and B. casei (~ 66 nmole α- ketobutyrate mg-1 h-1). Inoculation of wheat grains with each strain significantly enhanced growth. Z. coccineum rhizosphere harbors growth-promoting bacteria and ameliorated the negative effects of salt stress on wheat plants and may be used as an eco-friendly biofertilizer.