Analysis Of The Expression Profiles And ESTs Of Genes Involved In Floral Regeneration Induced By Hormones In Hyacinthus Orientalis L.

Particular type of floral organs can be induced from the regenerated floral buds of Hyacinthus orientalis by precisely controlling exogenous hormones in the medium. The regenerated floral buds produce only tepals when cultured on MS medium with 2,4-D (0.1 mg/l) and 6-BA (2 mg/l).Using the in vitro floral organ regeneration system, we constructed a cDNA library with floral tissues cultured at 5 days and 10 days under high concentration of auxin and cytokinin. The cDNA library was screened by cDNA microarray method. A number of clones involved in floral regeneration induced by hormones were acquired.To further understand the expression patterns of genes involved in hormone-regulated floral regeneration, expression profiles were constructed with 4608 clones chosen based on the results of the cDNA library screening. Labelled reverse transcripts of explants cultured at 5 days and 10 days under high level of hormones were used as positive probes, labelled reverse transcripts of explants uncultured were the negative probes. According to the result of hybridization, we got 1217 clones that showed the different patterns of expressions induced by hormones. Among them 947 clones (20.5%) whose expression increased induced by hormones might be hormonesupregulated. Rest of them (270 clones), however, might be hormones downregulated. From them, 90 clones were chosen for sequencing. By sequence analysis they represented 77 ESTs. They were categorized by homologies aligned in GeneBank. Data showed that 54 genes share high homology with genes of known functions in plantï¼›Other 23 genes share low homology with known genes in plant. Combining with the information from the sequences and the functions of their homology, we suggested the probable characteristics and functions of those genes.We isolated 26N1, a gene regulated by hormones, and determined its expression pattern. 26N1 cDNA is 1162bp in full length, and it encodes a putative zinc finger protein with 245 amino acids. Northern hybridization showed that 26N1 expressed in explants, levels of its mRNA increase dramatically when induced on MS medium high auxin and cytokinin for 1 day. However the levels of 26N1 decrease when cultured for 5 days and longer. Its mRNA was low in the explants cultured without hormones. In vivo, its mRNA can be detected in tepals, roots, stamens and carpels. That suggested it has taken part in several processes in plant development...