Study On Transformation Of PttKN1 Gene In Dianthus Caryophyllus And Celosia Cristata L

Celosia cristata L and Dianthus caryophyllus L are the important ornamental plants in the world. It will bring about great practical applications and big market if people can get their new and unusual varieties in morphology. PttKN1 (populus tremula×tremuoides knotted1) gene is a new number of KNOX gene isolated from the vascular cambial region of hybrid aspen. Its ectopic expression will lead to an alternation in morphology of plants. The introduction and expression of PttKN1 gene is a potential strategy to obtain new varieties of flower plants. In order to investigate the function of PttKN1 gene and obtain the transgenic plants in phenotype alternation, Celosia cristata L and Dianthus caryophyllus L were transformed by using Agrobacterium tumfaciens harbouring the plasmid containing PttKN1. The main results were as follows:1. An efficient regeneration system of Celosia cristata L was first established here. Callus and adventitious shoots were induced from hypocotyls explants. The optimum medium for Celosia cristata L to induce adventitious shoots was: MS medium supplemented with 6-BA (2.0mg/L), NAA (0.5mg/L) and IAA (0.5mg/L), from which the average rate of bud differentiation was 33%.2. RT-PCR analysis of transgenic plants showed that kanamycin-resistantregenerated plants of Celosia cristata L gave the positive expression but not in control. It indicated that PttKN1 gene had been integrated into Celosia cristata L genomes.3. When the PttKN1 gene was overexpressed in Celosia cristata L, transgenicplants exhibited typical phenotypical features that were different from wild-type plants: lobed leaves or rumpled; dissected leaves, in which the size was decreased and the thickness was increased. In addition, ectopic meristems formed and then two or three leaves produced on the same petiole.4. Dianthus caryophyllus L resistant to kanamycin generated several kinds of obvious phenotype different from wild-type plants, including: 1) changes of phyllotaxis : wild-type Dianthus caryophyllus was typical opposite phyllotaxis, while transgenic plants displayed tricussate whorled and multiple-cussate whorled phyllotaxis. And irregular change of phyllotaxis were also observed and thus their plants were acervate; 2) changes of stem: wild-type stems were round, however, some transgenic plants exhibited much thicker and flatter stem; 3) the whole transgenic plants of Dianthus caryophyllus became dwarf.The results above indicated that PttKN1 gene, a transcript factor, regulates a number of genes which are involved in the morphogenesis and development of plants. Transgenic plants altered in morphology may pay the foundation for the selection of novel flower varieties.