Genetic and epigenetic instability of amplification-prone sequences of a novel B chromosome induced by tissue culture in Plantago lagopus L.
Gene amplification is prevalent in many eukaryotes and has been found linked to various phenomena such as ontogenesis, carcinogenesis, in vitro culturing, neoplasia and drug resistance. Earlier, we reported a novel B chromosome in Plantago lagopus L., which was found to have arisen as a result of massive amplification of 5S rDNA. In addition, the chromosome is also composed of 45S rDNA and transposable elements. While the importance of gene amplification cannot be underestimated, its mechanism of origin is still unclear. Therefore, the aim of the present study was to determine whether amplification can be reactivated in the novel B chromosome. For this purpose, in vitro culture was used as stress. Three modes of tissue culture, i.e., direct, indirect and somatic embryogenesis were used for raising in vitro cultures. The variations due to genetic and epigenetic mechanisms were assessed in regenerants using molecular techniques, namely, PCR-RFLP, SSAP and MSAP. The retrotransposon-based molecular markers were applied to detect the polymorphism within transposable elements of in vitro regenerated and mother plants. We detected the variations that may be due to genetic changes either because of element recombination or activation of transposable elements which can lead to increase in the copy number. MSAP analysis revealed the differences in the DNA methylation pattern of the regenerants derived from novel chromosome bearing mother plants. Some regenerated plants were associated with increase and decrease in DNA methylation of both internal and external cytosine of the CCGG sequence.
Plant Genomics Laboratory, School of Biotechnology, University of Jammu, Jammu 180006, India.
Gurmeet
G
Kour
Balbir
B
Kour
Sanjana
S
Kaul
Manoj Kumar
MK
Dhar
D001483:Base Sequence; D032461:Chromosomes, Plant / Q000235:genetics*; D003470:Culture Media; D019175:DNA Methylation / Q000187:drug effects / Q000235:genetics; D021901:DNA, Intergenic / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D044127:Epigenesis, Genetic / Q000187:drug effects; D005784:Gene Amplification / Q000235:genetics*; D042822:Genomic Instability / Q000187:drug effects / Q000235:genetics*; D010937:Plant Growth Regulators / Q000494:pharmacology; D018515:Plant Leaves / Q000187:drug effects / Q000254:growth & development; D018520:Plant Shoots / Q000187:drug effects / Q000254:growth & development; D010943:Plantago / Q000187:drug effects / Q000235:genetics* / Q000502:physiology; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D012038:Regeneration / Q000187:drug effects / Q000235:genetics; D046509:Tissue Culture Techniques / Q000379:methods*
D003470:Culture Media; D021901:DNA, Intergenic; D004275:DNA, Ribosomal; D010937:Plant Growth Regulators