LLM-Domain B-GATA Transcription Factors Play Multifaceted Roles in Controlling Greening in Arabidopsis

Plant Cell. 2018 Mar;30(3):582-599. doi: 10.1105/tpc.17.00947. Epub 2018 Feb 16.

Abstract

Chlorophyll accumulation and chloroplast development are regulated at multiple levels during plant development. The paralogous LLM-domain B-GATA transcription factors GNC and GNL contribute to chlorophyll biosynthesis and chloroplast formation in light-grown Arabidopsis thaliana seedlings. Whereas there is already ample knowledge about the transcriptional regulation of GNC and GNL, the identity of their downstream targets is largely unclear. Here, we identified genes controlling greening directly downstream of the GATAs by integrating data from RNA-sequencing and microarray data sets. We found that genes encoding subunits of the Mg-chelatase complex and 3,8-divinyl protochlorophyllide a 8-vinyl reductase (DVR) likely function directly downstream of the GATAs and that DVR expression is limiting in the pale-green gnc gnl mutants. The GATAs also regulate the nucleus-encoded SIGMA (SIG) factor genes, which control transcription in the chloroplast and suppress the greening defects of sig mutants. Furthermore, GNC and GNL act, at the gene expression level, in an additive manner with the GOLDEN2-LIKE1 (GLK1) and GLK2 transcription factor genes, which are also important for proper chlorophyll accumulation. We thus reveal that chlorophyll biosynthesis genes are directly controlled by LLM-domain B-GATAs and demonstrate that these transcription factors play an indirect role in the control of greening through regulating SIGMA factor genes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / genetics
  • Arabidopsis / metabolism*
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Chlorophyll / metabolism
  • Chloroplasts / metabolism
  • GATA Transcription Factors / genetics
  • GATA Transcription Factors / metabolism*
  • Gene Expression Regulation, Plant
  • Transcription Factors / genetics
  • Transcription Factors / metabolism

Substances

  • Arabidopsis Proteins
  • GATA Transcription Factors
  • GLK1 protein, Arabidopsis
  • GLK2 protein, Arabidopsis
  • Transcription Factors
  • Chlorophyll