show Abstracthide AbstractMOP1-mediated regulation of gene expression of plant responses to early ABA induction has transcriptionally and physiologically relevant roles. Homozygous mop1-1 plants are compromised in their ability to recover from water deprivation. Purpose: Genome-wide identification of immediate and direct MOP1-dependent ABA transcriptional responses Methods: mRNA profiles of Mop1 wildtype and mop1-1 mutant V3 stage maize seedlings were subjected to ABA and MS treatments for 1 hour. The trimmed sequence reads were analyzed at the gene level using HISAT2, stringite, and edgeR. Results: we mapped ~33 million, 150 bp, paired-end sequence reads per sample to the B73 version 4 maize genome and identified 1,856 genes in four pairwise-comparisons to be differentially expressed genes (DEGs) with a log2FC = 0.95 and FDR <0.05, 1,119 DEGs were found to be unique to one genotype/treatment comparison. Conclusions: MOP1-mediated regulation of gene expression in maize seedlings in the RdDM (mop1-1) mutant has relevant transcriptional and physiological roles in plants subjected to stress. Our study generated by RNA-seq technology identified genes and biological processes regulated by RdDM and ABA-mediated stress responses, including MOP1-dependent and immediate response genes (MIMs). Overall design: RNA-seq was preformed on homozgyous Mop1 wildtype and mop1-1 mutant V3 seedling shoots with and without exogenous 50 µM ABA treatment for 1 hour.