Cloning And Transient Expression Assay Of BADH Gene Promoters From Dendronthema Lavandulifolium

Chrysanthemum[Dendronthema×grandiflora (Ramat.)Kitam.] is one of the ten traditional famous flowers in China and the four famous cutting flowers in the world. Great achievement has been attained in traditional breeding of chrysanthemum. In recent years, chrysanthemum breeding by genetic transformation has become a hotspot, and some primary achievements have been attained. Studies on transgene expression in chrysanthemum have focused on the 35S- CaMV (Cauliflower mosaic virus) promoter, which is a constitutive promoter. Its expressing time, site and level can't be controlled, and only low levels of expression were observed because it was from low organism. Though the expressing site can be fixed on by using tissue-specific promoter, and the expressing level can be improved enormously, the expressing time and level can't be regulated yet. However, the application of inducible promoter could hopefully solve the problems. It is valuable in theory and practice to fuse inducible promoters to ornamental character (such as florescence and flower color) genes of chrysanthemum to study the expressing behavior, and to breed by transgene ulteriorly. Betaine aldehyde dehydrogenase (BADH) gene is very important in the anabolism of betaine in many plants, which is induced by drought, salinity and abscisic acid (ABA). It is the easiest way to induce the expression of the gene by salt treatment. In this paper, based on the analysis of BADH gene resource in Compositae, four promoter sequences were cloned from Dendranthema lavandulifolium, which is very tolerant to salinity and drought. And the function of all of the sequences was identified preliminarily, which serves as an important basis for further expression analysis and transgenic research. The main results are summarized as follows:1. Twenty-four wild plants of Compositae, which are very tolerant to salinity and drought, were collected from Beijing and Hebei province. Two cultivated species and two chrysanthemum cultivars were collected too. BADH genes were found by PCR-Southern from twenty of all above plants. Some...