Transformation of PttKN1 gene to cockscomb

We have established a shoot regeneration system and genetic transformation of cockscomb ( Celosia cristata and Celosia plumosus ). The best results in terms of frequency of shoot regeneration and number of shoot buds per explant are observed on media supplemented with 0.5 mg l −1 6-BA (for explants of apical meristems of C. cristata ) or 2.0 mg l −1 6-BA, 0.5 mg l −1 NAA and 0.5 mg l −1 IAA (for hypocotyls explants of C. plumosus ). We use apical meristems of C. cristata and hypocotyls of C. plumosus as the starting material for transformation. A novel KNOTTED1-like homeobox1 ( KNOX ), PttKN1 ( Populus tremula × P. tremuoides knotted1 ) isolated from the vascular cambial region of hybrid aspen, is introduced into cockscomb by Agrobacterium . A series of novel phenotypes are obtained from the transgenic cockscomb plants, including lobed or rumpled leaves, partite leaves and two or three leaves developed on the same petiole, on the basis of their leaf phenotypes. Transformants are selected by different concentrations of kanamycin. Transformants are confirmed by PCR of the NptII gene and PCR or RT-PCR of PttKN1 gene. Furthermore, RT-PCR shows that 35S:: PttKN1 RNA levels do not correlate with phenotypic severity. It is discussed that our results bring elements on possible function of PttKN1 gene. To our knowledge, genetic transformation of cockscomb is first reported.