Abstract
BackgroundmicroRNAs (miRNAs) are endogenous small (~21 nucleotide) single-stranded non-coding RNAs that typically function by guiding cleavage of target genes. To find the miRNAs that may be involved in dark-induced leaf senescence, we identified miRNAs by microarray platform using Arabidopsis thaliana leaves from both whole darkened plants (DPs) and individually darkened leaves (IDLs).ResultsWe found that the expressions of 137 miRNAs (P < 0.01, signal intensity >0) were significantly changed both in DP and IDL leaves. Among them, the expression levels of 44 miRNAs were relative higher than others (P < 0.01, signal intensity >500). Of these differentially expressed miRNAs, 6 miRNAs (miR319a, 319c, miR159, miR164a, miR164c and miR390a) have been previously reported to be involved in dark-induced leaf senescence, and the remaining 38 miRNAs have not been implicated in leaf senescence before. Target genes of all 44 miRNAs were predicted, and some of them, such as NAC1, At3g28690, At2g17640 and At2g45160, were found in the Leaf Senescence Database (LSD). GO and KEGG analysis of 137 miRNAs showed that the predicted target genes were significantly enriched in transcription regulation, development-related biological processes and metabolic pathways. Expression levels of some of the corresponding miRNA targets (At1g73440, At2g03220 and At5g54810) were analysed and found to be significantly different in DP/IDL than that in WT.ConclusionsA microarray analysis about dark-induced miRNAs involved in leaf senescence are present here. Further expression analysis revealed that some new founding miRNAs maybe regulate leaf senescence in Arabidopsis, and the findings highlight the important role of miRNAs in dark-induced leaf senescence.Electronic supplementary materialThe online version of this article (doi:10.1186/s12870-015-0656-5) contains supplementary material, which is available to authorized users.
Highlights
MicroRNAs are endogenous small (~21 nucleotide) single-stranded non-coding RNAs that typically function by guiding cleavage of target genes
We aimed to identify miRNAs playing a role in dark-induced leaf senescence of Arabidopsis by using miRNAs microarray platform on darkened plants (DPs) and individually darkened leaves (IDLs)
Phenotype and Chl content analysis in the DPs and IDLs in Arabidopsis Upon dark treatment for 2 d, no increase in yellowing was observed in either DPs or IDLs, leaves began to lose pigment
Summary
MicroRNAs (miRNAs) are endogenous small (~21 nucleotide) single-stranded non-coding RNAs that typically function by guiding cleavage of target genes. Senescence in plants is an intrinsic, genetically determined, natural developmental programme that operates at the end of leaf, fruit, or flower development [1]. It is characterized by the visible yellowing (Chlorophyll degradation) of leaves accompanied by the mobilization of leaf nutrients to the reproductive structures, and is a complex process involving changes of physiological, biochemical and gene expression regulated by endogenous and exogenous factors [2]. Leaf senescence is controlled mainly by developmental age, it can be modulated or Senescence-like phenomena can be induced by incubation in darkness [5]. Dark-induced senescence programs share many common pathways with natural age-dependent senescence [10]. There are some similar symptoms and molecular components in the two conditions, with the exception of ROS production in mitochondria which increases markedly in dark-induced senescent pea leaves [11] and aged potato (Solanum tuberosum) tubers [12]
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