JXB Advance Access originally published online on January 5, 2006
Journal of Experimental Botany 2006 57(3):559-569; doi:10.1093/jxb/erj041
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Published by Oxford University Press [2006] on behalf of the Society for Experimental Biology.
RESEARCH PAPER |
SHR5: a novel plant receptor kinase involved in plantN2-fixing endophytic bacteria association
1Instituto de Bioquímica Médica, CCS, Universidade Federal do Rio de Janeiro, 21941-590 Rio de Janeiro, RJ, Brazil
2Laboratório de Biologia Molecular de Plantas, Instituto de Pesquisas do Jardim Botânico do Rio de Janeiro, Rua Pacheco Leão 915, 22460-030 Rio de Janeiro, RJ, Brazil
3CNPAB/EMBRAPA, BR465, Km47 23851-970 Seropédica, RJ, Brazil
* To whom correspondence should be addressed. E-mail: hemerly{at}bioqmed.ufrj.br
Endophytic nitrogen-fixing bacteria have been isolated from graminaceous plants such as maize, rice, and sugarcane. They are thought to promote plant growth, not only by fixing nitrogen, but also by the production of plant hormones. The molecular mechanisms involved in this interaction are not yet clear. In this work, the identification of a receptor-like kinase (RLK), named SHR5, which may participate in signal transduction involved in the establishment of plantendophytic bacteria interaction is described for the first time. SHR5 seems to be part of a novel subclass of RLKs present in a wide range of plant species. The expression of this gene is down-regulated in sugarcane plants associated exclusively with beneficial endophytic bacteria and is not a general response caused by micro-organisms or abiotic stress. In addition, more successful sugarcaneendophytic bacteria associations have a more pronounced decrease in SHR5 expression, suggesting that SHR5 mRNA levels in plant cells are inversely related to the efficiency of the association.
Key words: Biological nitrogen fixation, diazotrophic endophytic bacteria, gene expression, LRR-RLK receptors, plantmicrobe interaction, signalling, sugarcane