Seminars

Functional modularity confers an emergent property of Arabidopsis thaliana core root microbiota lineages

Title Functional modularity confers an emergent property of Arabidopsis thaliana core root microbiota lineages
Lecturer Dr. Ryohei Thomas Nakano (Max Planck Institute for Plant Breeding Research)
Language English
Date&Time 03/16/2018 (Fri) 15:00~16:00
Venue 大セミナー室
Detail
Plants in nature live in intimate association with diverse microorganisms, collectively called the plant microbiota. Taxonomic compositions of bacterial communities associated with the roots of a wide range of land plant species are largely overlapped, and the common bacterial lineages, including the order Rhizobiales, constitute the “core root microbiota”. Rhizobiales contains a group of bacteria, known as rhizobia, that are characterized by their symbiotic engagements with leguminous plants. However, the genetic and phenotypic nature of interaction between non-leguminous plants and non-symbiotic Rhizobiales is not understood. Our recent genome analysis of 1,314 Rhizobiales isolates originating from both leguminous and non-leguminous plant hosts showed that key symbiosis genes were acquired multiple times and that the most recent Rhizobiales common ancestor had the capacity to colonize the roots of a broad range of hosts. By conducting a large-scale gnotobiotic binary interaction survey, we identified root growth promoting (RGP) activity as a common trait of Rhizoabiales commensals. We also found that the Rhizobiales RGP is strongly inhibited by activation of host immune responses, and some root-associated bacteria, including some Rhizobiales commensals, suppressed host immune responses. We therefore tested a tripartite co-inoculation experiment and revealed that the Rhizobiales RGP under immune-eliciting conditions was rescued by co-inoculation with an immune-suppressing strain. These findings indicate that these traits synergistically operate in a modular fashion, suggesting interactions between these two traits that enable emergent properties of A. thaliana core root microbiota.
Contact 植物免疫学
西條 雄介 (saijo@bs.naist.jp)

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