Background and aims: Epigenetic regulation plays an important role in the management of plant growth, development and response to stress factors, and several reports have indicated that DNA methylation plays a critical role in seed development and viability. This study examines changes in 5-methylcytosine (m(5)C) levels in the DNA of seeds during ageing, a process that has important implications for plant conservation and agriculture.
Methods: Changes in the global level of m(5)C were measured in mature seeds of oak, Quercus robur. The extent of DNA methylation was measured using a protocol based on two-dimensional thin-layer chromatography. Viability of seeds was determined by germination and seedling emergence tests.
Key results: An ageing-related decrease in total m(5)C during storage of recalcitrant seeds was highly and significantly correlated with a decrease in seed viability, as reflected by a reduction in germination (r = 0·8880) and seedling emergence (r = 0·8269).
Conclusions: The decrease in viability during ageing of Q. robur seeds is highly correlated with a global decline in the amount of m(5)C in genomic DNA, and it is possible that this may represent a typical response to ageing and senescence in recalcitrant seeds. Potential mechanisms that drive changes in genomic DNA methylation during ageing are discussed, together with their implications for seed viability.
Keywords: 5-methylcytosine; DNA methylation; Quercus robur; dormancy; epigenetics; pendunculate oak; recalcitrant seed.; seed ageing.
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