Abstract
The plasmid pBI121
cry1Ab
used to transform peach explants to produce insect resistant plants was constructed by cloning the synthetic
cryIAb
gene with the intron of the castor bean catalase-1 gene into the pBI121 binary vector, under the control of the CaMV35S promoter. Leaf discs of peach (
Prunus persica
L.) were co-cultivated for two days with this construct in
A. tumefaciens
strain LBA 4404. Explants were plated on WPM medium supplemented with 125 mg L
−1
kanamycin, 3% sucrose, 2.5 mg L
−1
2,4-Dichlorophenoxyacetic acid, and 0.5 mg L
−1
6-benzyladenine in darkness for callus formation. The calli were then selected on WPM medium supplemented with 125 mg L
−1
kanamycin, 3% sucrose, 3.00 mg L
−1
Thidiazuron, 1.0 mg L
−1
kinetin, and 0.5 mg L
−1
indoleacetic acid in the light for at least five subcultures (with a regeneration efficiency of 91.8%). The integration of the
cry1Ab
gene into the peach genome was confirmed by polymerase chain reaction (PCR) and northern blot analysis. A transformation efficiency of 28% was obtained when leaves were incubated for 15 min with
A. tumefaciens
. The
cry1Ab
gene expression was confirmed using RT-PCR, northern blot hybridization, immune-strip test, and insect bioassays, respectively. For insect bioassay, it was evident that the protein cryIAb expressed in transformed peach plants showed 100% mortality at 1000 ppm against
Synanthedon exitiosa
larvae after 96 h. The obtained results demonstrated a significant improvement of cryIAb toxin protein against lepidopteron larvae in peach.
Key message
In vitro peach regeneration from in vitro leaves is difficult, as well as regeneration using the method of genetic transfer such as agrobacterium to impart the desired characteristics of the plants with the aim of improvement is very difficult. This paper is the first to transgenic peach plants carrying cry1Ab gene for insect resistance particularly the peach tree borer.