Finding the right rhizobacterial partner is key for plant growth promotion
Of the three tested rhizobacterial genera, none of the strains showed growth-promoting effects for all three plant species, indicating specificity in rhizobacteria-plant interactions (Figure 1 ). For example, Pbg established an effective partnership with Artemisia and Broccoli, whereas interaction with Arabidopsis was deleterious given the significant reduction in biomass and the accumulation of stress-related dark-purple anthocyanins in the leaves (Figure 1a ). Even when an effective partnership between rhizobacteria and the host took place, the extent of growth promotion can significantly differ as shown by the partnership between Pbg and Artemisia (~500%) and Broccoli (~50%). The temporal analyses of the rhizobacteria-host interactions also demonstrated that the establishment of an effective partnership was characterized by early and sustained induction of growth promotion as was shown for the interaction of Pbg with Artemisia and Broccoli (Figure 1e and f ). The differential growth response of the three plant species to Pbg inoculation exemplifies the importance of the right partnership for growth promotion.