Fig. 2.

Transgenic expression of TdDof induces stem solidness in hollow-stemmed lines pithless1 and Kronos. Cross-sections of the second internodes of nontransgenic (Left, hollow stem) and TdDof overexpression T1 transgenic lines (Right, solid stem) derived from pithless1 (A) and Kronos (B) at Zadoks stage 34. Scanning electron microscopy images of stem cross-sections showing the detailed stem anatomy in pithless1_Control_6 (nontransgenic line) (C and D) compared TdDof overexpression T1 transgenic line pithless1_4_3_3 (F and G). Light microscopy images of stem cross-sections (E and H). In the high-magnification view of the central regions of these sections (D, E, G, and H), parenchyma cells in and surrounding the central pith region are intact and more uniform in size in the TdDof overexpression T1 transgenic lines (G and H), whereas, in nontransgenic control lines in the comparable pith region, the cells are irregular or broken and collapsed (D and E). (Scale bars: A–C and F = 2 mm; D, E, G, and H = 500 µm.) Molecular analysis via ddPCR of TdDof transgene copy number and gene expression in independent T1 transgenic lines of pithless1 (I and J) and Kronos (K and L). Error bars denote SD across replicates (I–L). The same lines imaged in A and B were selected for molecular studies.