DNA methylation in recovery of Maize (Zea Mays L.) from maize streak

Abstract

DNA methylation influences regulation of gene expression during cell development and tissue differentiation in plants. This study therefore discussed the role of DNA methylation in the recovery of maize from Maize Streak Diseases (MSD). Bisulfite treatment and DNA sequencing methods were carried out on the 2^nd, 4^th 6^th and 8^th white to yellowish streaking leaves of five infected maize varieties (DMR-ESR-Y, TZEBR, and ART/98/SW6) to assess the disease severity using digital phenotyping. The bisulfite treatment utilizes various sensitivities of cytosine and 5-methylcytosine (5-MeC) to deamination by bisulfite under acidic conditions in which cytosine is converted to uracil, whereas 5-MeC remains unreactive. This study showed that DMR-ESR-Y variety significantly (p<0.05) tolerated best for MSD, while TZEBR and ART/98/SW6 varieties slightly tolerated MSD but were not significantly different. The analysis of the images from digital phenotyping revealed that DMR-ESR-Y variety had the highest level of resistance, followed by TZEBR while ART/98/SW6 showed mild resistance and DMR-LSR-Y had the least. The leaf length had strong positive correlation with leaf width (r=0.94), number of leaves(r=0.64), plant height (r=0.96) and stem height(r=0.96). The methylation patterns in bisulfite sequences across the same leaf positions were significantly different (p<0.05), thus suggesting that CG methylation could contribute to transcriptional gene silencing plant recovery mechanism in maize.