AUTHOR=Chamkhi Imane , Zwanzig Jessica , Ibnyasser Ammar , Cheto Said , Geistlinger Joerg , Saidi Rym , Zeroual Youssef , Kouisni Lamfeddal , Bargaz Adnane , Ghoulam Cherki 

TITLE=Siccibacter colletis as a member of the plant growth-promoting rhizobacteria consortium to improve faba-bean growth and alleviate phosphorus deficiency stress

JOURNAL=Frontiers in Sustainable Food Systems

VOLUME=Volume 7 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/sustainable-food-systems/articles/10.3389/fsufs.2023.1134809

DOI=10.3389/fsufs.2023.1134809

ISSN=2571-581X

ABSTRACT=The rhizosphere is a hot spot and a source of beneficial microorganisms as plant growth promoting rhizobacteria (PGPR). From the alfalfa (Medicago sativa) rhizosphere, 115 bacteria were isolated, and based on PGP traits screening, 26 interesting isolates were selected as PGP rhizobacteria for the next tests. The objective of this study is using a consortium of PGPR to enhance the growth of faba-bean under P deficiency by their ability to release phosphorus from rock phosphate (RP). Several examined strains were found to have a relatively high activity on phosphate (P) solubilization, auxin, siderophore, ammoniac production, antifungal activity, and the ability to tolerate hypersalinity and water stress. 16S rRNA gene sequencing of the collection revealed the identification of 6 different genera with Bacillus (46.15%), Siccibacter (23.07%), and Acinetobacter (15.38%) as the most abundant. Three of the interesting strains (Siccibacter colletis, Enterobacter huaxiensis, and Pantoea sp showed high plant growth promotion traits and no antagonism with Rhizobium laguerreae. These three bacteria were retained to establish a rhizobia-including consortium. The inoculation of faba-bean plants with the consortium improved growth parameters as roots and shoots dry biomasses and some physiological criteria (chlorophyll content, and P uptake under low P availability conditions) and the increase reached 40%. Our study could be the first report of faba-bean growth promotion by a multi-strain PGPR-rhizobia consortium involving S. colletis, E. huaxiensis, and Pantoea sp. Thus, this consortium could be recommended for faba-bean inoculation, particularly under P limiting conditions.