TITLE:
Water Stress Responsive Differential Methylation of Organellar Genomes of Zea mays Z59
AUTHORS:
Bhupathipalli Divya Bhanu, Kandasamy Ulaganathan, Arun K. Shanker
KEYWORDS:
Maize, Drought Stress, DNA Methylation, Epigenetics, Mitochondria, Chloroplast, RNA-Seq
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.11 No.7,
July
20,
2020
ABSTRACT: DNA methylation is an important epigenetic change
affecting gene expression in plants in both normal and stress conditions. The
organelles, mitochondria and chloroplast play a significant role in sensing and
initiating stress response. In this study, we report the methylation pattern in
chloroplast and mitochondrial genomes in irrigated and water stressed
conditions and its relationship with gene expression of a drought tolerant Zea mays cultivar, Z59. Whole genome bisulfite sequencing was done to analyze the
pattern of methylation in both the conditions. Mapping of bisulfite reads to
B73 reference of mitochondrial and chloroplast genomes showed hypomethylation
in water stressed plants when compared to irrigated plants. Sliding window
approach to the methylation count data showed highest peak at 419,800 to
420,800 bp region in mitochondria and at 36,900 to 37,900 bp region in
chloroplast genomes in both samples. Annotation of the methylated genomes
showed that, genes related to photosystem I & II in chloroplast and nad4
gene in mitochondria were hypo methylated in the water stressed sample. RNA-seq
analysis oftranscriptomics reads mapped to the same
reference showed regulation of rps3, rps2A, ccmFC, atp1 and many
uncharacterized genes in mitochondria and psbA, psbD, psbc, psaA, and atpA,
genes in chloroplast.