Microsatellite DNA somaclonal variation in micropropagated trembling aspen (Populus tremuloides)
ABSTRACT Microsatellite DNA markers of ten simple sequence repeat (SSR) loci were used to examine somaclonal variation in randomly selected micropropagated plantlets derived from three different Populus tremuloides donor trees (genotypes). The plantlets were obtained from tissue cultures of dormant vegetative buds, and those derived from the same donor tree, grown in the greenhouse, did not exhibit any sign of visible morphological variation. No microsatellite DNA variation was observed among 13 somaclones of one tree and 4 somaclones of another tree at eight of the ten SSR loci. However, despite the small number of micropropagated progeny per tree sampled, microsatellite DNA variation was detected among the plantlets derived from the same donor trees at two SSR loci. The primer pair for the SSR locus PTR5 revealed somaclonal variation in 1 out of the 13 plantlets obtained from one genotype, while the primer pair for the PTR2 SSR locus revealed somaclonal variation in one out of the four plantlets obtained from another genotype. The variation at the PTR2 locus resulted in the appearance of a new allele of increased size, possibly due to an addition of the repeat units, while the variation at the PTR5 locus resulted in the appearance of third allele, presumably due to the presence of a single extra chromosome or duplication of a chromosomal segment. These results demonstrate that the genetic fidelity of micropropagated plants of P. tremuloides cannot always be assured and somaclonal variation can occur even when tissues of well organized vegetative buds are used for tissue cultures; that somaclonal variation cannot always be detected at the gross morphological level; and that microsatellite DNA markers provide useful and sensitive markers for determining the clonal fidelity and somaclonal variation in P. tremuloides.
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ABSTRACT: Goldenrod (Solidago canadensis L.) is an invasive plant species in many countries except North America but a cut-flower species worldwide. There is a need to generate and propagate goldenrod clones efficiently for research and commercial purposes. A callus induction and plantlet regeneration system was developed by studying the influence of explant type and different concentrations of plant growth regulators. The highest callus production from leaf segments was obtained on Murashige and Skoog's medium (MS medium) supplemented with 1.0 mg/L naphthalene acetic acid (NAA) and 1.0 mg/L 6-benzylaminopurine (BA). Adventitious shoots could be regenerated directly from leaf explants without an intermediate callus phase with the highest shoot induction percentage of 87.2%. The largest number of adventitious shoots per leaf explant (3.2) was obtained on MS medium supplemented with 0.4 mg/L NAA and 2.0 mg/L BA. MS medium supplemented with 0.1 mg/L NAA and 1.0 mg/L BA was the best medium for axillary shoot regeneration from nodal segments. The highest root number and longest roots occurred on half-strength MS without the addition of any growth regulator. Rooted plantlets were then transferred to a soil-based growth medium, placed in a greenhouse, and acclimatized with 100% success. All surviving plants grew normally without showing any morphological variation when compared to those grow from seed. This regeneration protocol may be used to produce certain biotypes of goldenrod suitable for genetic transformation, rapid propagation of goldenrod for commercial purposes or for screening fungi and toxins as potential biocontrol agents against this weed.03/2012; 81(1):53-60. DOI:10.5586/asbp.2011.044
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ABSTRACT: ABSTRACT The investigation was carried out to assess the genetic stability in tissue culture raised plants of banana cv. G-9 using random amplified polymorphic DNA (RAPD) and inter simple sequence repeats (ISSR) markers. Aims: Molecular assessment of genetic stability of tissue culture raised plants of banana cv. G-9 using molecular markers. Material and Results: Apical shoots were established on medium EM4 (MS + BAP 4.0 mg L-1) with maximum of 3.8 buds/explants in 2.6 days. The maximum bud multiplication with 16.5±0.06 shoots was observed on medium Ma3 (MS medium+ 5.0 mg L-1 BAP + 0.25 mg L-1 NAA of + 30 mg L-1 AdSO4). The maximum rooting response (100%) was observed on 1/2 MS medium supplemented with 2.0 mg L-1 NAA in 12.2 days. After acclimatization the hardened plants were examined for genetic stability using RAPD and ISSR primers. Total forty six (twenty six RAPD and twenty ISSR) markers were used. RAPD primers produced 87 distinct and scorable bands, with an average of 3.34 bands per primer and the amplification products range was from 100-1200 bps. The number of scorable bands for RAPD primer varied from 2 to 5 with an average of 3.34 bands per primer. ISSR primers produced 71 distinct and scorable bands in the range of 100-1000 bps and the number of scorable bands for each primer varied from 2 to 6 with an average of 3.55 bands per primer. Conclusion: Similar profile with monomorphic bands was observed for all the tissue culture raised plants when compared to mother plant in both types of markers used. These results corroborate the fact that plant tissue culture technology has immense importance for production of true to type of planting material.
Planta Medica 04/2012; 78(05). DOI:10.1055/s-0032-1307509 · 2.34 Impact Factor