Arabidopsis RelA/SpoT homologs implicate (p)ppGpp in plant signaling

Erik A. van der Biezen, Jongho Sun, Mark J. Coleman, Mervyn J. Bibb, Jonathan D. G. Jones

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Arabidopsis RPP5 is a member of a large class of pathogen resistance genes encoding nucleotide-binding sites and leucine-rich repeat domains. Yeast two-hybrid analysis showed that RPP5 specifically interacts with At-RSH1, an Arabidopsis RelA/SpoT homolog. In Escherichia coli, RelA and SpoT determine the level of guanosine tetraphosphate (ppGpp) and guanosine pentaphosphate (pppGpp), which are the effector nucleotides of the bacterial stringent response. Functional analysis in E. coli and in Streptomyces coelicolor A3 (2) showed that At-RSH1 confers phenotypes associated with (p)ppGpp synthesis. We characterized two additional Arabidopsis RelA/SpoT homologs, At-RSH2 and At-RSH3. At-RSH genes may regulate a rapid plant (p)ppGpp-mediated response to pathogens and other stresses.

Original languageEnglish
Pages (from-to)3747-3752
Number of pages6
JournalProceedings of the National Academy of Sciences
Issue number7
Publication statusPublished - 28 Mar 2000

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