Fig. 3.

Gene expression analysis of the mtbs1-1 mutant. (A) Transcript profiling analysis of core cell cycle genes in expanding leaves in mtbs1-1. Shown is a heat map of log₂ fold changes in gene expression in vegetative shoot bud (VB) and young leaf (YL) samples between mtbs1-1 and A17. (B and C) Quantitative RT-PCR analysis of expression of Medicago HISTONE 4 (B) and CYCD3;3 (C) in young leaf, stipule, and seed samples in A17 and mtbs1-1 plants. Shows are means ± SD for n = 3. **P < 0.001, Student’s t test. (D) Transcript profiling analysis of genes whose homologs are known to regulate organ growth in A. thaliana. Shown is a heat map of log₂ fold changes in gene expression between mtbs1-1 and A17. (E and F) qRT-PCR analysis of expression of Medicago GRF5 (E) and GIF1 (F) in young seed, leaf, and stipule samples in A17 and mtbs1-1 plants. Shows are means ± SD for n = 3. **P < 0.001, Student’s t test. RNA samples were prepared from developing seeds at 6 DPA and leaflets and stipules of the second visible leaf from the shoot apex (B, C, E, and F). (G–J) RNA in situ hybridization shows that transcripts of MtGIF1 were detected in the shoot apical meristem (SAM), leaf primordia as early as P0 and lamina tissues in A17 (G) and mtbs1-1 (H). A sense probe for MtGIF1 did not detect any signals in neighboring tissue sections in A17 (I) and mtbs1-1 (J). (Scale bars: 100 µm.)