Fig. 2

LjPUB13 is expressed in symbiotically active root and nodules. a LjPUB13 expression in uninoculated L. japonicus roots vs roots inoculated by M. loti at 7, 14, 21 and 28 days post inoculation and 14, 21 and 28-day-old nodules. Transcript levels were normalized to those of UBQ. Bars represent means (+SE) of three biological replications (n = 8). Significant differences (P < 0.05) are indicated by asterisk. b, c, d, f Expression of LjPUB13 in L. japonicus transgenic hairy roots transformed with a ProPUB13::GUS construct, detected after GUS staining. In both uninoculated (b, c) and inoculated roots (d, f), PUB13 promoter activity was observed in the vascular bundle. At uninoculated plants strong LjPUB13 expression is detected in lateral root initiation sites (c, arrows). After rhizobial inoculation (d, f), LjPUB13 promoter was active in nodule promordia and young developing nodules at 7dpi (d, arrows) but not in mature nodules at 21dpi (f). e and g show the tissues colonised by DsRed-expressing rhizobia in (d) and (f), respectively. Bars, 500 μm