Suppression and restoration of lesion formation in arabidopsis Isd mutants

Kris Weymann, Michelle Hunt, Scott Uknes, Urs Neuenschwander, Kay Lawton, Henry York Steiner, John Ryals

Research output: Contribution to journalArticlepeer-review

173 Scopus citations


Systemic acquired resistance (SAR) is a broad-spectrum, systemic defense response that is activated in many plant species after pathogen infection. We have previously described Arabidopsss mutants constitutively SAR and concomitantly develop lesions simulating disease (lsd). Here, we describe two new mutants, lsd6 and lsd7, that develop spontaneous necrotic lesions possess elevated levels of salicylic acid (SA) as well as heightened disease resistance, similar to the previously characterized lsd and accelerated cell death (acd2) mutants. Genetic analysis of lsd6 lsd7 that the mutant phenotypes as simple dominant traits. When crossed with transgenic Arabidopsis plants containing the SA-degrading enzyme salicylate hydroxylase, the F1 progeny showed suppression of both SAR gene expression and resistance. In addition, salicylate hydroxylase suppressed lesion formation in the F1 progeny, suggesting that SA or some SA-dependent process may have a role in pathogen-associated cell death. Surprisingly, lesions were restored in the lsd6 F1 progeny after the application of either 2,6-dichloroisonicotinic acid or SA. Lesions were not restored by with either compound in the lsd7 F1 plants. Our findings demonstrate that steps early in the signal transduction pathway leading to SAR and disease resistance are potentiated by later events, suggesting feedback control of lesion formation.

Original languageEnglish (US)
Pages (from-to)2013-2022
Number of pages10
JournalPlant Cell
Issue number12
StatePublished - 1995
Externally publishedYes

ASJC Scopus subject areas

  • Plant Science
  • Cell Biology


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