DNA Methylation in Sugarcane Genotypes under Water Deficit Stress

Abstract

DNA methylation is one of the process involved in the regulation of gene expression in plant’s response to environmental stresses. Hence, methylation-sensitive amplified polymorphisms (MSAP) were used to evaluate the effect of water deficit stress on the extent and patterns of DNA methylation in sugarcane leaves. Sugarcane cultivar KPS 94-13 and KPS 01-11-6 plantlets were subjected to water deficit stress for 12 h, 1, 3 and 5 days by adding 16% PEG 6000 into culture medium. Changes in DNA methylation and polymorphism in methylated DNA were assessed by using selective MSAP primer combinations. Water deficit induced genome-wide DNA methylation polymorphisms accounted for 64.2 % and 65.1% of the total bands at all time-points in KPS 01-11-6 and KPS 94-13, respectively. The number of hyper-methylated band (type IV) was stable in KPS 01-11-6 but increased considerably in KPS 94-13 in comparison with the control. The changes in cytosine methylation banding patterns between control and water deficit stress were compared. These finding indicated that alteration in DNA methylation under water deficit stress occurred in two sugarcane genotypes. The water deficit stress induced more DNA  demethylation than DNA methylation in KPS 01-11-6 whereas the level of DNA methylation was increased in KPS 94-13. Based on the BLAST results of polymorphic methylated fragments, the cloned fragments showed significant homology to known sequences of NADH-plastoquinone oxidoreductase subunit K(ndhK) gene, hexokinase-1 gene and ribosomal RNA gene.