title: Genetic dissection of Rhizobium-induced infection and nodule organogenesis in pea based on ENOD12A and ENOD5 expression analysis.
abstract: In legumes, perception of rhizobial lipochitooligosacharide-based molecules (Nod factors) and subsequent signal transduction triggers transcription of plant symbiosis-specific genes (early nodulins). We present genetic dissection of Nod factor-controlled processes in Pisum sativum using two early nodulin genes PsENOD12a and PsENOD5, that are differentially up-regulated during symbiosis. A novel set of non-nodulating pea mutants in fourteen loci was examined, among which seven loci are not described in Lotus japonicus and Medicago truncatula. Mutants defective in Pssym10, Pssym8, Pssym19, Pssym9 and Pssym7 exhibited no PsENOD12a and PsENOD5 activation in response to Nod factor-producing rhizobia. Thus, a conserved signalling module from the LysM receptor kinase encoded by Pssym10 down to the GRAS transcription factor encoded by Pssym7 is essential for Nod factor-induced gene expression. Of the two investigated genes, PsENOD5 was more strictly regulated; not only requiring the SYM10-SYM7 module, but also SYM35 (NIN transcription factor), SYM14, SYM16 and SYM34. Since Pssym35, Pssym14, Pssym34 and Pssym16 mutants show arrested infection and nodule formation at various stages, PsENOD5 expression seems to be essential for later symbiotic events, when rhizobia enter into plant tissues. Activation of PsENOD12a only requires components involved in early steps of signalling and can be considered as a marker of early symbiotic events preceding infection.
authors.affiliation: All-Russia Research Institute for Agricultural Microbiology (ARRIAM), St. Petersburg, Russia. elena_dolgikh@arriam.spb.ru
authors.forename: E A
authors.initials: EA
authors.lastname: Dolgikh
authors.forename: I V
authors.initials: IV
authors.lastname: Leppyanen
authors.forename: M A
authors.initials: MA
authors.lastname: Osipova
authors.forename: N V
authors.initials: NV
authors.lastname: Savelyeva
authors.forename: A Y
authors.initials: AY
authors.lastname: Borisov
authors.forename: V E
authors.initials: VE
authors.lastname: Tsyganov
authors.forename: R
authors.initials: R
authors.lastname: Geurts
authors.forename: I A
authors.initials: IA
authors.lastname: Tikhonovich
mesh_terms: D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D018744:DNA, Plant / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D008070:Lipopolysaccharides / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation; D018532:Pisum sativum / Q000235:genetics* / Q000378:metabolism / Q000382:microbiology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D055170:Plant Root Nodulation; D012231:Rhizobium / Q000502:physiology*; D016415:Sequence Alignment; D015398:Signal Transduction; D013559:Symbiosis; D014157:Transcription Factors / Q000378:metabolism; D014170:Transformation, Genetic
chemical_list: D018744:DNA, Plant; D008070:Lipopolysaccharides; D008565:Membrane Proteins; C092736:Nod factor, Rhizobium leguminosarum; D010940:Plant Proteins; D014157:Transcription Factors; C045625:nodulin