Transformation of muskmelon parental line (Cucumis melo L. var. reticulatus Ser.) with an antisense ACC oxidase gene.

摘要

Muskmelon explants develop profuse direct regeneration when cultured in vitro. Despite this high in vitro regeneration, Galia muskmelon has been recalcitrant to transformation by Agrobacterium tumefaciens. Nunez-Palenius et al (2001) reported that when using a cotyledon based protocol, Galia male and female parental lines are readily transformable with Agrobacterium tumefaciens. Transformation of Galia male parental line with an antisense ACC oxidase (ACO-1) gene is described herein. Explants were transformed using Agrobacterium tumefaciens strain ABI, which contained the vector pMON 11054 bearing an antisense gene of ACC oxidase and a glyphosate-tolerance gene. Putative transformants were selected on the basis of their capacity to grow on glyphosate-enriched medium, and by the presence of both ACC oxidase antisense and CP4 syn (glyphosate-tolerance) genes. Both ACO and CP4 syn genes were assessed by a polymerase chain reaction method. Leaf tissue from transgenic plants had greater ACC oxidase activity in vitro and produced more ethylene than leaf tissue wild type. ACC oxidase activity in vivo was similarly greater from transgenic plants than wild type plants. Possibly, the constitutive expression of the ACC oxidase antisense gene induced a functional compensation for ethylene production in vegetative tissue. However, transgenic fruits from ACO-1 antisense male line plants produced less ethylene and have a longer shelf life compared to wild type fruits.