GNC and CGA1 modulate chlorophyll biosynthesis and glutamate synthase (GLU1/FD-GOGAT) expression in Arabidopsis

Darryl Hudson, David Guevara, Mahmoud W. Yaish, Carol Hannam, Nykoll Long, Joseph D. Clarke, Yong Mei Bi, Steven J. Rothstein

Research output: Contribution to journalArticle

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Abstract

Chloroplast development is an important determinant of plant productivity and is controlled by environmental factors including amounts of light and nitrogen as well as internal phytohormones including cytokinins and gibberellins (GA). The paralog GATA transcription factors GNC and CGA1/GNL up-regulated by light, nitrogen and cytokinin while also being repressed by GA signaling. Modifying the expression of these genes has previously been shown to influence chlorophyll content in Arabidopsis while also altering aspects of germination, elongation growth and flowering time. In this work, we also use transgenic lines to demonstrate that GNC and CGA1 exhibit a partially redundant control over chlorophyll biosynthesis. We provide novel evidence that GNC and CGA1 influence both chloroplast number and leaf starch in proportion to their transcript level. GNC and CGA1 were found to modify the expression of chloroplast localized GLUTAMATE SYNTHASE (GLU1/Fd-GOGAT), which is the primary factor controlling nitrogen assimilation in green tissue. Altering GNC and CGA1 expression was also found to modulate the expression of important chlorophyll biosynthesis genes (GUN4, HEMA1, PORB, and PORC). As previously demonstrated, the CGA1 transgenic plants demonstrated significantly altered timing to a number of developmental events including germination, leaf production, flowering time and senescence. In contrast, the GNC transgenic lines we analyzed maintain relatively normal growth phenotypes outside of differences in chloroplast development. Despite some evidence for partial divergence, results indicate that regulation of both GNC and CGA1 by light, nitrogen, cytokinin, and GA acts to modulate nitrogen assimilation, chloroplast development and starch production. Understanding the mechanisms controlling these processes is important for agricultural biotechnology.

Original languageEnglish
Article numbere26765
JournalPLoS One
Volume6
Issue number11
DOIs
Publication statusPublished - Nov 10 2011

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Glutamate Synthase
Biosynthesis
Chloroplasts
Chlorophyll
Arabidopsis
Nitrogen
chloroplasts
Cytokinins
biosynthesis
chlorophyll
cytokinins
nitrogen
Germination
glutamate synthase (ferredoxin)
Light
Starch
assimilation (physiology)
Genes
GATA Transcription Factors
genetically modified organisms

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Medicine(all)

Cite this

GNC and CGA1 modulate chlorophyll biosynthesis and glutamate synthase (GLU1/FD-GOGAT) expression in Arabidopsis. / Hudson, Darryl; Guevara, David; Yaish, Mahmoud W.; Hannam, Carol; Long, Nykoll; Clarke, Joseph D.; Bi, Yong Mei; Rothstein, Steven J.

In: PLoS One, Vol. 6, No. 11, e26765, 10.11.2011.

Research output: Contribution to journalArticle

Hudson, Darryl ; Guevara, David ; Yaish, Mahmoud W. ; Hannam, Carol ; Long, Nykoll ; Clarke, Joseph D. ; Bi, Yong Mei ; Rothstein, Steven J. / GNC and CGA1 modulate chlorophyll biosynthesis and glutamate synthase (GLU1/FD-GOGAT) expression in Arabidopsis. In: PLoS One. 2011 ; Vol. 6, No. 11.
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