Parasitic plant Cistanche tubulosa shapes the bacterial community structure and functional composition of the salt-tolerant host Tamarix chinensis across different parasitic statuses

Root-associated microbiomes are crucial for assisting host and parasitic plants cope with environmental stress. However, little research exists on bacterial community characteristics of parasites and hosts under different parasitic statuses. In this study, we used Cistanche tubulosa and Tamarix chinensis as parasitic and host plant models, respectively, and aimed to determine the assembly mechanisms and role in assisting plants in salt stress tolerance of root-associated bacterial communities. The different parasitic statuses are closely related to the variations in bacterial communication and community assembly mechanisms between the host and parasitic plants. The percentages of potential microbiota sourced from the parasite to the host (44.83% and 83.50%) were greater than those from the host to the parasite (17.50% and 54.67%) in the re-parasitism and flowering stages, illustrating that parasites play a dominant role in shaping the host root microbiota. In addition, the host has a more complex and robust root microbiota co-occurrence network than the parasite does, whereas the KEGG results revealed that the predicted bacterial communities of the parasite-associated microbiota contain more genes in plant growth promotion, salt‒alkali stress resistance, and substance metabolism. Moreover, the salinity, NH 4 + , and total potassium were significantly correlated with the bacterial community distributions of the two plants. Our results indicate that parasitic status significantly affects the distribution of root bacterial communities, bacterial transfer, and material metabolism of the two plants at different parasitic statuses, reflecting the adaptive mechanisms of plants and bacteria under parasitic relationships and providing ideas for the utilization of saline-alkaline land.