DNA-methylation changes in grapevine somaclones following in vitro culture and thermotherapy

Abstract

The methylation-sensitive amplified polymorphism (MSAP) technique using HpaII and MspI isoschizomers was used to analyse DNA-methylation alterations in stressed grapevine plants. The stress used was in vitro propagation via nodal segments and in vitro thermotherapy for virus elimination. A set of pertinent grapevine plants derived from two cultivars (18 plants each for Müller Thurgau and Riesling) was used as stressed variants for analyses. A total of 695 and 700 MSAP bands were recognised and evaluated as present/absent for all analysed variants derived from both cvs. Müller Thurgau and Riesling. Average computed similarity of MSAP banding between analysed variants (Dice/Nei and Li coefficient) was 0.935 for both cultivars. Clustering of variants within resulting dendrograms showed significant differences between woody cuttings despite originating from the one plant. Further, there was a strong 'donor' effect of maternal plants on future arrays of DNA methylation in their regenerants. The 'donor' effect even seemed to prevail in the effect of stress on final DNA-methylation state in stressed regenerants. Additional MSAP evaluation suggests that thermotherapy induced an additional array of methylation changes when compared with stress caused by in vitro cultivation. From the viewpoint of whether methylation of CCGG loci increased/decreased due to stress, the results showed moderate prevalence for decreasing CCGG loci methylation.

Vernalization and photoperiod-related changes in the DNA methylation state in winter and spring rapeseed

“…The exposure of plants to diverse, abnormal temperatures or photoperiods can be a strong stress factor. Changes in the level of DNA methylation in MSAP analyses were reported in response to various environmental factors or treatments (Tatra et al 2000;Labra et al 2004;Baranek et al 2010). In rapeseed, the methylation/demethylation events at MSAP loci were the result of the salt stress (Lu et al 2007) and in Zea mays roots a genome-wide demethylation was observed under cold stress (Steward et al 2002).…”

A review of somaclonal variation in plantain (<i>Musa</i> spp): mechanisms and applications

“…Global methylation levels and methylation of specific sites are documented in several crops, e.g. oil palm (Jaligot et al 2000), grapevine (Schellenbaum et al 2008, Baránek et al 2010 and apple (Li et al 2002). In addition, epigenetic changes such as DNA methylation and histone modifications may be associated with the physiological responses of the plant cells to the conditions in vitro (Smulders et al 2011).…”

Epigenetics in plant tissue culture

“…(G. de Klerk, unpublished observations). Baránek et al (2010) reported differences in DNA methylation between lines established from different nodes on the same parent plant. In several crops unwanted epigenetic variation caused in tissue culture is a major drawback.…”

“…Oh et al (2007) hypothesised that labile portions of the genome are affected by stress during micropropagation of Musa. Alterations in methylation have been reported in response to water deficiency (Labra et al 2002), osmotic stress (Kovařik et al 1997), heavy metals (Aina et al 2004), and-in tissue culture-heat (Baránek et al 2010). Some loci acquired epigenetic silencing, while sometimes silenced loci increased expression.…”