Effects of ethephon on DNA methylation and gene expressions associated with shortened internodes in maize

Abstract

In this study, the molecular mechanism underlying ethephon-induced shortened internodes in maize was investigated using Zhengdan958 maize variety. The ethephon treatment was performed by spraying 225 mL/ha Ethephon 40% SL onto the foliage at the eight-expanded-leaves stage. The differentially expressed genes in the young internodes under ethephon treatment were identified through methylation-sensitive amplified fragment length polymorphism (MSAP), start codon targeted polymorphism (SCoT) and cDNA-amplified fragment length polymorphism (AFLP) analyses. MSAP results showed the methylation sites were widely distributed in both the ethephon-treated (at 27.8%) and control plants (30.1%). This suggested that ethephon treatment modified the methylation patterns; with 3.0% of the sites being hyper-methylated and 7.3% demethylated compared with the control. Based on SCoT analysis, 148 transcript derived fragments (TDFs) were obtained in the ethephon-treated plants. Among them, 38 were upregulated (25.7%) and 47 down-regulated (31.8%). cDNA-AFLP analysis using 70 primer pairs identified 1635 TDFs in the ethephon-treated and the control plants. Of these, 600 and 564 TDFs were up-and down-regulated by the ethephon treatment, respectively. BLASTX analysis on 50 (randomly selected) differentially expressed TDFs divided them into several categories based on their putative biological functions: signal transduction (6%), resistance-related (14%), energy and metabolism (22%), transcription (4%), cell apoptosis (2%), unknown functional proteins (42%) and unknown genes (10%). Our results revealed that ethephon treatment could induce DNA methylation variation principally by increasing the demethylation tendency. This is suggested to play roles in stress-defence genes expression regulation and the differentially expressed genes could be associated with shortened internodes in maize.

MSAP analysis reveals diverse epigenetic statuses in opium poppy varieties with different benzyisoquinoline alkaloid content

“…Therefore, the study of epigenetics in plants has been a focus of researchers for a long time. DNA methylation is one of the key epigenetic modifications and is known to play an important role in regulating gene expression during several biological processes (Ci et al, 2015;He et al, 2017;Ngom et al, 2017;Yao et al, 2018). Although the influence of epigenetics on transcriptional control has been widely studied, less is known about its tissue-specificity.…”