Abstract
The plant-oncogenic 6b gene from Agrobacterium tumefaciens causes auxin localization in tobacco. To study further the auxin localization, we applied 1-naphthoxyacetic acid (NOA, a specific auxin influx carrier inhibitor) to the tobacco seedlings transgenic for the dexamethasone (Dex)-inducible 6b gene. In the presence of Dex alone, tumor developed only abaxial side of cotyledons and auxin (IAA) was localized to the periphery of tumor as well as vascular bundles. In contrast, the presence of both Dex and NOA resulted in the reduction of the abaxial tumor, and the newly development tumors growth hypocotyls. The seedlings became shooty calli at high concentration of NOA. Seedlings containing both 6b gene and IAA responsive reporter gene construct DR5::GUS indicated that IAA was localized to the junction of normal tissue and tumor. Thus, NOA induced additional redistribution of IAA and morphological alterations which had been caused by the 6b gene in tobacco.
