Induction of Synthetic Polyploids and Assessment of Genomic Stability in Lippia alba

Abstract

Polyploidy is widely recognized as a major evolutionary force in plants and has been reported in the genus Lippia (Verbenaceae). Lippia alba, the most studied species, has been documented as a polyploid complex involving at least four ploidal levels. L. alba presents remarkable chemical and genetic variation and represents a model for understanding genome organization. Although the economic and medicinal importance of the species has been widely described, no established polyploid induction protocol has been reported so far. Here, we describe the production of synthetic polyploid plants of L. alba using colchicine. The ploidal levels were estimated by flow cytometry and chromosome counting. In addition, FISH and molecular markers approaches were used to confirm the stability of the synthetic polyploids. The major component of the essential oils was estimated by GCMS to compare with the natural individuals. Tetraploids and triploids were produced providing new opportunities for investigating medicinal, pharmacological, and economic applications as well as addressing intrinsic questions involved in the polyploidization process in tropical plants.

Induced autopolyploidy—a promising approach for enhanced biosynthesis of plant secondary metabolites: an insight

“…Supposedly, there was modification in the gene expression in hexaploids leading to repression and/or de-repression of genes for phenolic acid biosynthesis. Such quantitative and non-quantitative changes leading to biosynthesis of novel phytochemicals originally not detected in their diploid parents were also reported most recently [ 64 , 65 , 70 ]. Cara et al [ 70 ] in their experimental findings documented comparative variations in the secondary biometabolite productions among induced autopolyploids and allopolyploids of Solanum tuberosum and Solanum kurtzianum (Table 1 ).…”

“…Both the extremities of doses stand unprofitable either due to non-effectivity or lethality [ 61 , 79 ]. Different experimental results testify to the corollary that varied autopolyploids like mixoploids and tetraploids have been obtained due differential durations of treatment [ 64 ]. Changes in secondary cellular metabolism inflicted due to varied colchicine durations were also reported in recent past [ 57 , 63 ].…”

“…1.83-fold) [ 61 ] Thymus vulgaris L. Oryzalin (dissolved in 1% DMSO) treatment➔ sterile H 2 O washing➔ culture in MS Nodal segment Oryzalin; 80 μM; 24 h Diploid➔tetraploid (2n=4x=60) Essential oil content increase (from 0.81 to 1.19%); increase in thymol (18.01%) and carvacol (0.49%) [ 62 ] Melissa officinalis L. Soaked in colchicine soln. Seedling Colchicine; 0.1%; 24 h Diploid➔tetraploid (2n=4x=64) Increase in carotenoid content (2.9-fold) [ 63 ] Colchicine; 0.05%; 24 h Increase in phenolic content (4 times) Colchicine; 0.1%; 48 h Increase in flavonoid content (4.93-fold) Lippia alba Inoculation in colchicine +MS medium Nodal segment Colchicine; 0.2%; 72 h Colchicine; 0.2%; 4 h Diploid➔tetraploid (2n=4x=60) Diploid➔mixoploid Increase in linalool content; insignificant change in ctiral content [ 64 ] Zingiber officinale Roscoe cv. ‘Fengtou’ ginger MSL + colchicine soln.…”

Induction of Polyploidy and Metabolic Profiling in the Medicinal Herb Wedelia chinensis

“…The α-terpineol was absent in the essential oil of colchicine-induced tetraploid plants of ajowan medicinal plant, while this compound was present (0.31%) in essential oil in diploid WT [ 22 ]. In Lippia alba , a major component of citral was not detected in the essential oil of some of the colchicine-induced triploids, and the linalool component was absent from the chemical profile of the majority of tetraploids [ 23 ]. New compounds such as α-humulene, α-terpineol and viridiflorol have also been detected in the essential oil of induced tetraploids of Tetradenia riparia , these compounds were not seen in the chemical profile of diploid plants [ 24 ].…”

Polyploidy in tissues of plants in vitro of grape somaclones

“…Achieving the undoubted advantages that polyploid organisms possess is the aim of many breeders who use induced polyploidy and natural polyploids to create new plant varieties [3]. Polyploid forms of plants are characterized by increased organ sizes compared to diploid varieties, buffering of harmful mutations, increased heterozygosity and heterosis [3][4][5]. Polyploidy allows obtaining seedless varieties due to errors that occur in meiosis; at the same time, doubling the genome in a sterile hybrid allows restoring its fertility [3,6].…”