Figure 3.

Mobility of nonmobile mRNAs overexpressed in transgenic potato phloem companion cells. A, Representative SUC2prom::AtCHL1 transgenic potato/wild-type (WT) potato heterograft. The white box indicates the graft union (GU). The image at right shows an enlargement of the region boxed at left. Bars = 2 cm. B, Reverse transcription (RT)-PCR analysis of AtAMT1;2 and AtCHL1 in transgenic potato grafts. Both AtAMT1;2 and AtCHL1 are phloem-immobile mRNAs. Transgenic potato plants with overexpressed AtAMT1;2 or AtCHL1 were grafted onto the wild type, and the expression of these genes in the rootstock was compared with that in the homografts in which the scion and the rootstock were the same genotype (wild type or transgenic). For the transgenic/wild-type grafts, three shoots excised from the same transgenic potato plant with either overexpressed AtAMT1;2 or AtCHL1 were grafted on the tomato rootstock.