Genome-wide characterization of maize small RNA loci and their regulation in the Required to maintain repression6-1 (Rmr6-1) mutant and long-term abiotic stresses

Alice Lunardon, Cristian Forestan, Silvia Farinati, Michael Axtell, Serena Varotto

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20 Scopus citations


Endogenous small RNAs (sRNAs) contribute to gene regulation and genome homeostasis, but their activities and functions are incompletely known. The maize genome has a high number of transposable elements (TEs; almost 85%), some of which spawn abundant sRNAs. We performed sRNA and total RNA sequencing from control and abiotically stressed B73 wild-type plants and rmr6-1 mutants. RMR6 encodes the largest subunit of the RNA polymerase IV complex and is responsible for accumulation of most 24-nucleotide (nt) small interfering RNAs (siRNAs). We identified novel MIRNA loci and verified miR399 target conservation in maize. RMR6-dependent 23-24 nt siRNA loci were specifically enriched in the upstream region of the most highly expressed genes. Most genes misregulated in rmr6-1 did not show a significant correlation with loss of flanking siRNAs, but we identified one gene supporting existing models of direct gene regulation by TE-derived siRNAs. Long-term drought correlated with changes of miRNA and sRNA accumulation, in particular inducing down-regulation of a set of sRNA loci in the wild-typeleaf.

Original languageEnglish (US)
Pages (from-to)1535-1548
Number of pages14
JournalPlant physiology
Issue number3
StatePublished - Mar 1 2016


All Science Journal Classification (ASJC) codes

  • Physiology
  • Genetics
  • Plant Science

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