Crosstalk between biotic and abiotic stress responses in tomato is mediated by the AIM1 transcription factor

Synan Abuqamar, Hongli Luo, Kristin Laluk, Michael V. Mickelbart, Tesfaye Mengiste

Research output: Contribution to journalArticlepeer-review

137 Citations (Scopus)

Abstract

Plants deploy diverse molecular and cellular mechanisms to survive in stressful environments. The tomato (Solanum lycopersicum) abscisic acid-induced myb1 (SlAIM1) gene encoding an R2R3MYB transcription factor is induced by pathogens, plant hormones, salinity and oxidative stress, suggesting a function in pathogen and abiotic stress responses. Tomato SlAIM1 RNA interference (RNAi) plants with reduced SlAIM1 gene expression show an increased susceptibility to the necrotrophic fungus Botrytis cinerea, and increased sensitivity to salt and oxidative stress. Ectopic expression of SlAIM1 is sufficient for tolerance to high salinity and oxidative stress. These responses correlate with reduced sensitivity to abscisic acid (ABA) in the SlAIM1 RNAi, but increased sensitivity in the overexpression plants, suggesting SlAIM1-mediated ABA responses are required to integrate tomato responses to biotic and abiotic stresses. Interestingly, when exposed to high root-zone salinity levels, SlAIM1 RNAi plants accumulate more Na+, whereas the overexpression lines accumulate less Na+ relative to wild-type plants, suggesting that SlAIM1 regulates ion fluxes. Transmembrane ion flux is a hallmark of early responses to abiotic stress and pathogen infection preceding hypersensitive cell death and necrosis. Misregulation of ion fluxes can result in impaired plant tolerance to necrotrophic infection or abiotic stress. Our data reveal a previously uncharacterized connection between ABA, Na+ homeostasis, oxidative stress and pathogen response, and shed light on the genetic control of crosstalk between plant responses to pathogens and abiotic stress. Together, our data suggest SlAIM1 integrates plant responses to pathogens and abiotic stresses by modulating responses to ABA.

Original languageEnglish
Pages (from-to)347-360
Number of pages14
JournalPlant Journal
Volume58
Issue number2
DOIs
Publication statusPublished - Apr 1 2009
Externally publishedYes

Keywords

  • ABA-induced R2R3MYB
  • Botrytis cinerea
  • Salt stress
  • Solanum lycopersicum
  • Tomato

ASJC Scopus subject areas

  • Genetics
  • Plant Science
  • Cell Biology

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