Abstract
The hypersensitive response (HR), a type of programmed cell death that is accompanied by DNA degradation and loss of plasma membrane integrity, is a common feature of plant immune responses. We previously reported that transcription of IREN which encodes a novel EF-hand containing plant nuclease is controlled by OsNAC4, a key positive regulator of HR cell death. Transient overexpression of IREN in rice protoplasts also led to rapid DNA fragmentation, while suppression of IREN using RNA interference showed remarkable decrease of DNA fragmentation during HR cell death. Maximum DNA degradation associated with the recombinant IREN was observed in the presence of Ca2+ and Mg2+ or Ca2+ and Mn2+. Interestingly, DNA degradation mediated by the recombinant IREN was completely abolished by Zn2+, even when Ca2+, Mg2+, or Mn2+ were present in the reaction buffer. These data indicate that IREN functions in the degradation of nuclear DNA during HR cell death.
Graphical abstract
IREN, novel EF-hand containing plant nuclease, functions in the degradation of nuclear DNA during immune-related hypersensitive cell death.
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Acknowledgments
The authors acknowledge Hiromi Morii for excellent technical support.
Disclosure statement
No potential conflict of interest was reported by the authors.
Notes
The nucleotide sequence reported in this paper has been submitted to NCBI database accession numbers AK100514 (IREN).