Adaptive bacterial and fungal matching between a parasitic plant and its host: A case of Cistanche deserticola and Haloxylon ammodendron

How the unique heterotrophic life history of parasitic plants influences the root and rhizosphere microbiota of symbiotic host plants is relatively unknown. In this study, we used Cistanche deserticola and Haloxylon ammo-dendron from cultivated populations as our model parasite and host plants, respectively. We collected samples from root (PR) and rhizosphere (PS) of the parasite, root (HIR) and rhizosphere (HIS) of the host plant infected, and root (HUR) and rhizosphere (HUS) of host plant uninfected. We conducted Illumina high-throughput DNA sequencing technology, and compared the diversity, composition, co-occurring network structure of their microbiota, and traced the composition of the parasitic plant microbiota. Our results showed that the diversity of root bacteria and fungi was lower than those in the rhizosphere, the co-association complexity of the root was simpler than those of the rhizosphere, but the compositional similarity of root microbiota was increased relative to those of the rhizosphere. Infection had localized and systemic effects on microbiota of HIR and HIS. Seven taxa were enriched in HIR and HIS, including Microvigra, Sphingomonas, Rubrobacter, Gaiella, Quadrisphaera, Chae-tomium, and Penicillum. Additionally, infection also led to the co-association network of HIR being simpler than HUR. Meanwhile, the diversity, composition, and co-association network were similar between PR and HUR. Community assembly mechanisms analysis showed that the variable selection and homogenizing dispersal were highly similar between C. deserticola (Bacteria: 0.8 and 0.2; Fungi: 0.4 and 0.4) and H. ammodendron (Bacteria: 0.8 and 0.2; Fungi: 0.4 and 0.36). And PR displayed a high level of congruence with HUR in both bacterial (t0=0.69) and fungal (t0=0.53) communities. Collectively, our results suggested that the root microbiota of parasitic plant was highly congruent with those of the host plant, consistent with the phenomena of 'parasitic equilibrium'. Our findings on parasite and host microbiota provide a new novel line of evidence supporting the complex interaction of parasitic plants and their hosts.

Automated summary

This study compared the root and rhizosphere microbiota of parasitic and host plants, finding that the microbiota of the root was less diverse but more similar to the host. Infection had localized and systemic effects on the host's microbiota. The results support the idea of "parasitic equilibrium" and provide evidence for the complex interaction between parasitic plants and their hosts.