期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2010
卷号：107
期号：1
页码：478-483
DOI：10.1073/pnas.0910081107
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：To establish compatible rhizobial-legume symbioses, plant roots support bacterial infection via host-derived infection threads (ITs). Here, we report the requirement of plant flotillin-like genes (FLOTs) in Sinorhizobium meliloti infection of its host legume Medicago truncatula. Flotillins in other organisms have roles in viral pathogenesis, endocytosis, and membrane shaping. We identified seven FLOT genes in the M. truncatula genome and show that two, FLOT2 and FLOT4, are strongly up-regulated during early symbiotic events. This up-regulation depends on bacterial Nod Factor and the plant's ability to perceive Nod Factor. Microscopy data suggest that M. truncatula FLOT2 and FLOT4 localize to membrane microdomains. Upon rhizobial inoculation, FLOT4 uniquely becomes localized to the tips of elongating root hairs. Silencing FLOT2 and FLOT4 gene expression reveals a nonredundant requirement for both genes in IT initiation and nodule formation. FLOT4 is uniquely required for IT elongation, and FLOT4 localizes to IT membranes. This work reveals a critical role for plant flotillins in symbiotic bacterial infection.
