Figure 4.

ZNT1 expression in T. caerulescens and T. arvense. Total RNA was isolated from roots and shoots of T. caerulescens (Tc) and T. arvense (Ta) grown for 14 days in a modified Johnson's solution with 0 (−) or 1 (+) μM Zn. The Northern blot, equally loaded with 7 μg of total RNA per lane, depicts the extremely high ZNT1 transcript abundance in T. caerulescens roots and shoots when probed with the full-length cDNA of ZNT1. Visualization of rRNA indicated that total RNA was equally loaded (data not shown). A subsequent probing with a gene-specific 0.4-kb fragment of the ZNT1 homolog from T. arvense (ZNT1-arvense) revealed that ZNT1 is expressed in the nonaccumulator under Zn deficiency in both the roots and shoots. Signals from both probes indicate a transcript size of ≈1.2 kb.