LIN, a novel type of U-Box/WD40 Protein, controls early infection by rhizobia in legumes

Ernö Kiss, Boglárka Oláh, Péter Kaló, Monica Morales, Anne B. Heckmann, Andrea Borbola, Anita Lózsa, Katalin Kontár, Patrick Middleton, J. Allan Downie, Giles E.D. Oldroyd, Gabriella Endre

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54 Citations (Scopus)


The formation of a nitrogen-fixing nodule requires the coordinated development of rhizobial colonization and nodule organogenesis. Based on its mutant phenotype, lumpy infections (lin), LIN functions at an early stage of the rhizobial symbiotic process, required for both infection thread growth in root hair cells and the further development of nodule primordia. We show that spontaneous nodulation activated by the calcium- and calmodulin-dependent protein kinase is independent of LIN; thus, LIN is not necessary for nodule organogenesis. From this, we infer that LIN predominantly functions during rhizobial colonization and that the abortion of this process in lin mutants leads to a suppression of nodule development. Here, we identify the LIN gene in Medicago truncatula and Lotus japonicus, showing that it codes for a predicted E3 ubiquitin ligase containing a highly conserved U-box and WD40 repeat domains. Ubiquitin-mediated protein degradation is a universal mechanism to regulate many biological processes by eliminating rate-limiting enzymes and key components such as transcription factors. We propose that LIN is a regulator of the component(s) of the nodulation factor signal transduction pathway and that its function is required for correct temporal and spatial activity of the target protein(s).

Original languageEnglish
Pages (from-to)1239-1249
Number of pages11
JournalPlant physiology
Issue number3
Publication statusPublished - Nov 1 2009


ASJC Scopus subject areas

  • Physiology
  • Genetics
  • Plant Science

Cite this

Kiss, E., Oláh, B., Kaló, P., Morales, M., Heckmann, A. B., Borbola, A., Lózsa, A., Kontár, K., Middleton, P., Downie, J. A., Oldroyd, G. E. D., & Endre, G. (2009). LIN, a novel type of U-Box/WD40 Protein, controls early infection by rhizobia in legumes. Plant physiology, 151(3), 1239-1249.