title: In vitro polyploidy induction: changes in morphology, podophyllotoxin biosynthesis, and expression of the related genes in Linum album (Linaceae).
abstract: Induction of tetraploidy was performed and podophyllotoxin production increased by upregulating the expression level and enzyme activity of genes related to its biosynthesis in tetraploid compared to diploid Linum album. Linum album is a valuable medicinal plant that produces antiviral and anticancer compounds including podophyllotoxin (PTOX). To achieve homogeneous materials, in vitro diploid clones were established, and their nodal segments were exposed to different concentrations and durations of colchicine. This resulted in successful tetraploidy induction, confirmed by flow cytometry, and is being reported for the first time. The highest efficiency of tetraploid induction (22%) was achieved after 72 h exposure to 2.5-mM colchicine treatment. The stable tetraploids were produced after being subcultured three times, and their ploidy stability was confirmed after each subculture. The effects of autopolyploidy were measured on the morphological and phytochemical characteristics, as well as enzyme activity and the expression levels of some key genes involved in the PTOX biosynthetic pathway, including phenylalanine ammonia-lyase (PAL), cinnamoyl-Coa reductase (CCR), cinnamyl-alcohol dehydrogenase (CAD), and pinoresinol-lariciresinol reductase (PLR). The tetraploid plants had larger leaves and stomata (length and width) and lower density stomata. Increasing the ploidy level from diploid to tetraploid resulted in 1.39- and 1.23-fold enhancement of PTOX production, respectively, in the leaves and stem. The increase in PTOX content was associated with upregulated activities of some enzymes studied related to its biosynthetic pathway and the expression of the corresponding genes. The expression of the PAL gene and PLR enzymatic activity had the most positive correlation with the ploidy level in both leaf and stem tissues. Our results verified that autotetraploid induction is a useful breeding method, remarkably increasing the PTOX content in the leaves and stem of L. album.
authors.affiliation: Department of Plant Breeding, Faculty of Agriculture, Tarbiat Modares University, P. O. Box 14115-336, Tehran, Iran.
authors.forename: Neda
authors.initials: N
authors.lastname: Javadian
authors.affiliation: Department of Plant Breeding, Faculty of Agriculture, Tarbiat Modares University, P. O. Box 14115-336, Tehran, Iran. karimzadeh_g@modares.ac.ir.
authors.forename: Ghasem
authors.initials: G
authors.lastname: Karimzadeh
authors.affiliation: Department of Plant Biology, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran.
authors.forename: Mohsen
authors.initials: M
authors.lastname: Sharifi
authors.affiliation: Department of Plant Breeding, Faculty of Agriculture, Tarbiat Modares University, P. O. Box 14115-336, Tehran, Iran.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Moieni
authors.affiliation: Department of Genetics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran.
authors.forename: Mehrdad
authors.initials: M
authors.lastname: Behmanesh
mesh_terms: D000445:Aldehyde Oxidoreductases / Q000235:genetics / Q000378:metabolism; D005434:Flow Cytometry; D019658:Linaceae / Q000235:genetics / Q000378:metabolism*; D010650:Phenylalanine Ammonia-Lyase / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D011034:Podophyllotoxin / Q000378:metabolism*; D011123:Polyploidy
chemical_list: D010940:Plant Proteins; D000445:Aldehyde Oxidoreductases; C019904:cinnamoyl CoA reductase; D010650:Phenylalanine Ammonia-Lyase; D011034:Podophyllotoxin
keywords: Flow cytometry; Gene expression; Linum album; Podophyllotoxin; Tetraploidy