Analyse On The DNA Methylation Of The Twin-seedling Rice (Oriza Sativa) 3N And 2N Under Salt Stress

Plant growth and development are badly hindered by the declining soil water potential resulted from too much salt,which has become the main reason for improving salty soil planted crop harvests.At present,20%cultivable land is in face of salt injury all over the world.Polyploids distribute more widely than diploids, which may show that polyploids have more genetic advantages on resisting adversities.But we still know little about the real reason of that.Nowadays,polyploids evolution and gene expression have become the focus of this field.The main result from those studies was the rapid gene expression differentiation after polyploidization, including polymorphic expression-change patterns among individuals and among organs.Those researches focused on synthetic allopolyploid with even ploidy such as wheat,corn,brassica and etc.Only a few cases were made on autopolyploid such as in yeast and Arabidopsis;things were the same when it came to natural polyploid except several recent allopolyploids,such as Spartina,Tragopogon and Senecio;Few researches were conducted on DNA methylation mutation and gene expression change of rice natural-genesic triploid.Recently,Boyko's study said that the latest findings in the field of epigenetics and the process of a reversible control over gene expression and inheritance lead to believe that organisms,especially plants,may have a flexible short-term strategy of the response to stress.At the same time,Vanyushin concluded that DNA methylation controls all genetic functions and is a mechanism of cellular differentiation and gene silencing;an essential role of DNA methylation in regulation of genetic processes is a fundament of materialization of epigenetics and epigenomics.So we consider that it's feasible and necessary to study on plant resistance in the way of DNA methylation,which is the key aspect of epigenetics.SARâ…¡-628 autotriploid and corresponding diploid salt-stress rice plant having the natural genesis from twin-seedling was employed as research material:in this study. Isoschizomers Hpaâ…¡and Mspâ… were employed to analyze methylation mutation during salt stress.The main results showed that,compared with the controls,both salt-stressed autotriploid and diploid show increased methylation levels in all methylation types except for double-strand-outside methylation type which held the line.