Background Soil microbial communities afect above-ground plant diversity and community composition by
infuencing plant growth performance. Several studies have tested the efect of soil bacterial microbiome on growth
performance of native and invasive plants, but the infuence of specifc bacterial isolates has not been investigated.
Here, we investigated the efects of soil bacterial exclusion by soil sterilization and by inoculation of Streptomyces
rhizobacterial isolates on the growth performance of native and invasive Prosopis congeners.
Results Plant growth performance of invasive P. julifora was signifcantly reduced when grown in sterilized soils,
whereas native P. cineraria showed enhanced growth performance in the sterilized soils. When grown in the soil
inoculated with the specifc Streptomyces isolate from P. julifora (PJ1), the growth performance of invasive P. julifora
was signifcantly enhanced while that of native P. cineraria seedlings was signifcantly reduced. However, inoculation
of P. cineraria and P. julifora seedlings with Streptomyces isolate from the rhizosphere of native P. cineraria (PC1) had no
signifcant efect on the growth performances either of P. julifora or P. cineraria.
Conclusion Our study reveals that invasive P. julifora experiences positive feedback from the non-native soil bacterial
community, while the native P. cineraria experiences negative feedback from its soil bacterial community. Our results
provide fresh experimental evidence for the enemy release hypothesis, and further our understanding of the contrasting growth-promoting efects of diferentially recruited microbial species belonging to the same genus (Streptomyces)
in the rhizospheres of alien invasive and native plants