Transforming embryogenic cell lines of Gladiolus with either a bar-uidA fusion gene or cobombardment

Abstract

Embryogenic cell lines of Gladiolus were bombarded with the bar-uidA fusion gene under the cauliflower mosaic virus (CaMV) 35S promoter (pDM327) or cobombarded with uidA under the CaMV 35S promoter (pBCG) and bar under the CaMV 35S promoter (pDM307). Over 500 cell lines were isolated for either the fusion gene or cobombarded cells following selection on Murashige and Skoog's medium supplemented with 2 mg 1−1 (9 μM) 2,4-dichlorophenoxyacetic acid and 6 mg 1−1 phosphinothricin. The optimum DNA concentration for, isolating stable transformants was one-tenth that for optimal isolation of lines with gus expression, and three times as many cell lines were isolated following cobombardment as compared to bombardment with the bar-uidA fusion gene. Three times as many cell lines (72% of the cell lines) containing the bar-uidA fusion gene expressed gus as compared to cobombarded cell lines (23%) following histological staining. Gus expression ceased after 1 yr in culture for 5% of the cell lines containing the fusion gene and 3% of the cobombarded cell lines. The bifunctionality and utility of the bar-uidA fusion gene were demonstrated, accompanied by enhanced gus expression.