WRINKLED1, a key regulator of oil biosynthesis, also affects hormone homeostasis
The Arabidopsis WRINKLED1 transcription factor affects auxin homeostasis in roots.
The Science
In this study, we further characterized a mutant gene (wri1-1) in the plant Arabidopsis that leads to strong reduction in seed oil content. We also identified a primary root defect and confirmed altered homeostasis in auxin, a growth regulator that plays an important role in plant development.
The Impact
Knowing that the transcription regulator WRINKLED1 (WRI1) affects hormone homeostasis could help us to engineer crops for increased oil content.
Summary
WRINKLED1 (WRI1) is a key transcriptional regulator of fatty acid biosynthesis genes in diverse oil-containing tissues. Loss of function of Arabidopsis WRI1 leads to a reduction in the expression of genes for fatty acid biosynthesis and glycolysis, and concomitant strong reduction of seed oil content. The wri1-1 loss-of-function mutant shows reduced primary root growth and decreased acidification of the growth medium. Additional characterization of the mutant revealed: increased content of a conjugated form of the plant growth hormone auxin (indole-3-acetic acid (IAA)-Asp); increased expression of GH3.3, a gene encoding an enzyme involved in auxin degradation; decreased auxin transport; and reduction of some PIN genes, which encode IAA carrier proteins. DNA binding assays demonstrated that AtWRI1 bound to the promoter of GH3.3 and some PIN genes. It is well known that auxin exerts its maximum effects at a specific, optimal concentration in roots requiring a finely balanced auxin homeostasis. This process appears to be disrupted when the expression of WRI1 and in turn a subset of its target genes are misregulated, highlighting a role for WRI1 in root auxin homeostasis.
Contacts (BER PM)
N. Kent Peters
Program Manager, Office of Biological and Environmental Research
kent.peters@science.doe.gov, 301-903-5549
(PI Contact)
Christoph Benning
Michigan State University
benning@msu.edu
Funding
This research was supported by the DOE Great Lakes Bioenergy Research Center (DOE Office of Science BER DE-FC02-07ER64494). The Danforth Center proteomics and mass spectrometry facility, used for this study, was supported by the National Science Foundation (grant no. DBI-0521250).
Publications
Kong, Q. et al. “The Arabidopsis WRINKLED1 transcription factor affects auxin homeostasis in roots.” Journal of Experimental Botany (2017) [DOI: 10.1093/jxb/erx275].
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