Poster
Kanako Inoue
Nara Institute of Science and Technology
Ikoma, Nara, Japan
Masako Fuji
Nara Institute of Science and Technology
Ikoma, Nara, Japan
John Jewish Arellano Dominguez
Assistant Professor
Nara Institute of Science and Technology
Ikoma, Nara, Japan
Masanao Sato
Hokkaido University
Sapporo, Hokkaido, Japan
Takumi Murakami
Tokyo Institute of Technology
Tokyo, Tokyo, Japan
Yusuke Saijo
Professor
Nara Institute of Science and Technology
Ikoma, Nara, Japan
Plants accommodate and utilize root-inhabiting microbes to adapt to adverse conditions, such as nutrient deficiencies, but the mechanisms underlying the mutualistic interactions remain poorly understood. A key layer of infection control involves immunogenic peptides known as phytocytokines, including plant elicitor peptides (Peps), which strengthen defense signaling via the leucine-rich repeat receptor kinases PEPRs. Here, we identify a panel of mutualistic bacteria in rice that colonize roots in a manner dependent on OsPep receptor1 (OsPEPR1), promoting plant growth under phosphate- deficient conditions. Genetic and cell biological analyses reveal a critical role for OsPEPR1 in regulating iron homeostasis, aligning with the requirement of iron for bacterial mutualism. Additionally, regulators of mycorrhizal symbiosis, including the Ca2+/calmodulin-dependent protein kinase CCaMK, are essential for bacterial colonization and plant growth promotion (PGP) at distinct stages, separate from OsPEPR1. Transcriptome and functional analyses further suggest that these bacteria enhance phosphate acquisition during mutualism. Collectively, our findings indicate that rice integrates both immunity and symbiosis pathways to facilitate mutualistic interactions with PGP bacteria in paddy fields, where mycorrhizal symbiosis is not effectively established.