A Consortium of Rhizosphere-Competent Actinobacteria Exhibiting Multiple Plant Growth-Promoting Traits Improves the Growth of Avicennia marina in the United Arab Emirates

Gray mangrove ( Avicennia marina ) is the dominant vegetation distributed along coast of United Arab Emirates (UAE). Despite its performance as natural coastal guardians, very little known about reforestation projects to increase cover over years in UAE and Arabian Gulf. Plant growth-promoting actinobacteria (PGPA) were isolated from rhizosphere sediments found evaluated for their potential produce plant growth regulators (PGRs) enhance under seawater irrigation conditions. In vitro screening identified nine rhizosphere-competent actinobacterial isolates, a naturally competitive environment, which Streptomyces coelicoflavus Sc showed high phosphorus solubilizing activity. Moreover, polychromogenes Sp ), bacillaris Sb ferrugineus Sf produced auxins, polyamines (PAs), 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase, respectively. Although sediment inoculation with single isolates significantly improved dry biomass shoots (43.2–74.0%) roots (40.8–75.9%), consortium / caused greater weight (82.1%) (81.6%) compared seawater-irrigated plants (control). our greenhouse experiments, levels photosynthetic pigments, planta PAs increased tissues inoculated ; whereas ACC contents reduced. This was also evident maximum velocity rubisco carboxylation (Vc max four-fold treated mixture control. To best knowledge, this first study reporting culturable halotolerant, PGPA inhabiting salty arid ecosystems applied individually or combination promote harsh conditions such those areas.