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J Exp Bot. 2014 Jun;65(9):2507-20. doi: 10.1093/jxb/eru141. Epub 2014 Apr 10.

Down-regulation of AUXIN RESPONSE FACTORS 6 and 8 by microRNA 167 leads to floral development defects and female sterility in tomato.

Author information

  • 1The Ohio State University, Ohio Agricultural Research and Development Center, Department of Horticulture and Crop Science, Wooster, OH 44691, USA.
  • 2The Ohio State University, Department of Molecular Genetics, Columbus, OH 43210, USA.
  • 3Boyce Thompson Institute for Plant Research, Ithaca, NY 14853, USA.
  • 4University of North Carolina, Department of Biology, Chapel Hill, NC 27599-3280, USA.
  • 5The Ohio State University, Ohio Agricultural Research and Development Center, Department of Horticulture and Crop Science, Wooster, OH 44691, USA Vanderknaap.1@osu.edu.

Abstract

Auxin regulates the expression of diverse genes that affect plant growth and development. This regulation requires AUXIN RESPONSE FACTORS (ARFs) that bind to the promoter regions of these genes. ARF6 and ARF8 in Arabidopsis thaliana are required to promote inflorescence stem elongation and late stages of petal, stamen, and gynoecium development. All seed plants studied thus far have ARF6 and ARF8 orthologues as well as the microRNA miR167, which targets ARF6 and ARF8. Whether these genes have broadly conserved roles in flower development is not known. To address this question, the effects of down-regulation of ARF6 and ARF8 were investigated through transgenic expression of Arabidopsis MIR167a in tomato, which diverged from Arabidopsis before the radiation of dicotyledonous plants approximately 90-112 million years ago. The transgenic tomato plants overexpressing MIR167a exhibited reductions in leaf size and internode length as well as shortened petals, stamens, and styles. More significantly, the transgenic plants were female-sterile as a result of failure of wild-type pollen to germinate on the stigma surface and/or to grow through the style. RNA-Seq analysis identified many genes with significantly altered expression patterns, including those encoding products with functions in 'transcription regulation', 'cell wall' and 'lipid metabolism' categories. Putative orthologues of a subset of these genes were also differentially expressed in Arabidopsis arf6 arf8 mutant flowers. These results thus suggest that ARF6 and ARF8 have conserved roles in controlling growth and development of vegetative and flower organs in dicots.

© The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology.

KEYWORDS:

ARF6; ARF8; expression; female sterility; flower development; tomato.

PMID:
24723401
[PubMed - in process]
PMCID:
PMC4036516
Free PMC Article
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