Access

Letters to Nature

Nature 421, 79-83 (2 January 2003) | doi:10.1038/nature01204; Received 1 August 2002; Accepted 7 October 2002

Chloroplast to nucleus communication triggered by accumulation of Mg-protoporphyrinIX

Åsa Strand1,2, Tadao Asami3, Jose Alonso1, Joseph R. Ecker1 & Joanne Chory1,2

  1. Plant Biology Laboratory, The Salk Institute, La Jolla, California 92037, USA
  2. the Howard Hughes Medical Institute; and The Salk Institute, La Jolla, California 92037, USA
  3. Plant Functions Laboratory, Riken, Wako, Saitama 351-0198, Japan

Correspondence to: Joanne Chory1,2 Correspondence and requests for materials should be addressed to J.C. (e-mail: Email: Chory@salk.edu).

Top

Plant cells coordinately regulate the expression of nuclear and plastid genes that encode components of the photosynthetic apparatus. Nuclear genes that regulate chloroplast development and chloroplast gene expression provide part of this coordinate control. There is evidence that information also flows in the opposite direction, from chloroplasts to the nucleus1, 2. Until now, at least three different signalling pathways have been identified that originate in the plastid and control nuclear gene expression3, 4 but the molecular nature of these signals has remained unknown. Here we show that the tetrapyrrole intermediate Mg-protoporphyrin (Mg-ProtoIX) acts as a signalling molecule in one of the signalling pathways between the chloroplast and nucleus. Accumulation of Mg-ProtoIX is both necessary and sufficient to regulate the expression of many nuclear genes encoding chloroplastic proteins associated with photosynthesis.