a1 USDA-ARS, National Forage Seed Production Research Center, Corvallis, Oregon 97331, USA;
a2 Department of Horticulture, Oregon State University, Corvallis, OR 97331, USA
MicroRNAs (miRNAs) are involved in developmental programmes of plants, including seed germination and post-germination. Here, we provide evidence that two different miRNA pathways, miR156 and miR172, interact during the post-germination stages in Arabidopsis. Mutant seedlings expressing miR156-resistant SQUAMOSA PROMOTER-BINDING PROTEIN-LIKE13 (mSPL13), which has silent mutations in the miR156 complementary sequence, over-accumulated SPL13 mRNA and exhibited a delay in seedling development. Microarray analysis indicated that SCHNARCHZAPFEN (SNZ), an AP2-like gene targeted by miR172, was down-regulated in these mutants. Quantitative reverse transcription-polymerase chain reaction (RT-PCR) and miRNA gel blot analyses showed that the MIR172 genes were up-regulated in mSPL13 mutants. These results suggest that the miRNA regulation cascades (miR156SPL13 → miR172SNZ) play a critical role during the post-germination developmental stages in Arabidopsis.
(Received November 19 2009)
(Accepted January 27 2010)
(Online publication March 17 2010)
p1 Present addresses: Department of Biosciences, Faculty of Science and Engineering, Teikyo University, Japan.
p2 Boyce Thompson Institute for Plant Research, Tower Road, Ithaca, NY 14853, USA.
p3 Synthetic Genomics, Inc., La Jolla, CA 92037, USA.
p4 Department of Plant Physiology and Biotechnology, University of Warmia and Mazury, Oczapowskiego 1A, 10-718, Olsztyn, Poland.
p5 Division of Plant and Crop Sciences, University of Nottingham, Sutton Bonington Campus, Loughborough, Leics, LE12 5RD, UK.
p6 Directorate of Seed Research, Kushmaur, Kaithauli, Mau Nath Bhanjan-275101, Uttar Pradesh, India.
a R.C.M. and M.A. contributed equally to this work.