EXPRESSION OF CRY1AC AND GUS IN CABBAGE AND CAULIFLOWER

Studies on the expression of a GUS reporter gene and a cry1Ac gene under the control of the proprietary tCUP gene expression system have been carried out in vegetable crucifers.
The tCUP gene expression system is comprised of a cryptic gene activation sequence isolated from tobacco by T-DNA tagging and has been optimized for expression in cauliflower transient and stable expression systems.
This optimization and concomitant development of effective transformation protocols, allowed a cry1Ac insect resistance gene to be introduced into an inbred line of cabbage and a hybrid line of cauliflower.
Here, we describe the regeneration optimization approach and extend the observations by evaluating the expression of a GUS reporter gene and a cry1Ac insecticidal protein gene in different parts of transgenic cauliflower and cabbage. A high level of expression was observed in all plant parts, especially in leaf tissue of cauliflower and cabbage and this high level of expression was consistent throughout plant development to senescence.
The results, using ELISA, showed that the cry1Ac gene, directed by the tCUP gene expression system, produced a high level of CRY protein.
Insect bioassays of transgenic cabbage and cauliflower lines showed no significant leaf damage after exposure to the larvae and 100% mortality of three target insect larvae (Imported cabbage worm, Diamond back moth and Cabbage looper). The results confirm the utility of the tCUP gene expression system for heterologous gene expression and the effectiveness of the use of Bt genes for Lepidopteron pest control in vegetable crucifers such as cabbage and cauliflower.