Ancient microRNA target sequences in plants

Floyd, Sandra K.; Bowman, John L.

doi:10.1038/428485a

Cited by 374 publications

(266 citation statements)

References 12 publications

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“…Our results show that most of the predicted targets have conserved functions with those of the miRNA targets in Arabidopsis. The highly conserved nature of miRNA target sequences among a wide variety of plant species has been reported by many researchers (Floyd and Bowman, 2004). In the present study, the majority of target genes were transcription factors such as SBPs, Apetala 2, and many other DNA and RNA binding proteins.…”

Section: Discussionsupporting

confidence: 62%

Identification of Potential microRNAs and Their Targets in Brassica rapa L.

Dhandapani

Ramchiary

Pavlidis

et al. 2011

Molecules and Cells

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MicroRNAs (miRNAs) are recently discovered, noncoding, small regulatory RNA molecules that negatively regulate gene expression. Although many miRNAs are identified and validated in many plant species, they remain largely unknown in Brassica rapa (AA 2n =, 20). B. rapa is an important Brassica crop with wide genetic and morphological diversity resulting in several subspecies that are largely grown for vegetables, oilseeds, and fodder crop production. In this study, we identified 186 miRNAs belonging to 55 families in B. rapa by using comparative genomics. The lengths of identified mature and pre-miRNAs ranged from 18 to 22 and 66 to 305 nucleotides, respectively. Comparison of 4 nucleotides revealed that uracil is the predominant base in the first position of B. rapa miRNA, suggesting that it plays an important role in miRNA-mediated gene regulation. Overall, adenine and guanine were predominant in mature miRNAs, while adenine and uracil were predominant in pre-miRNA sequences. One DNA sequence producing both sense and antisense mature miRNAs belonging to the BrMiR 399 family, which differs by 1 nucleotide at the, 20 th position, was identified. In silico analyses, using previously established methods, predicted 66 miRNA target mRNAs for 33 miRNA families. The majority of the target genes were transcription factors that regulate plant growth and development, followed by a few target genes that are involved in fatty acid metabolism, glycolysis, biotic and abiotic stresses, and other cellular processes. Northern blot and qRT-PCR analyses of RNA samples prepared from different B. rapa tissues for 17 miRNA families revealed that miRNAs are differentially expressed both quantitatively and qualitatively in different tissues of B. rapa.

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Section: Discussionsupporting

confidence: 62%

Identification of Potential microRNAs and Their Targets in Brassica rapa L.

Dhandapani

Ramchiary

Pavlidis

et al. 2011

Molecules and Cells

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“…miRNA-mediated gene regulation is an ancient gene regulation mechanism conserved among all lineages of land plants [28] and even predates the divergence of plant and animal kingdoms. The plant genomes have experienced significant rearrangement as demonstrated by the fact that members of most miRNA gene families were scattered around the plant genomes.…”

Section: Discussionmentioning

confidence: 99%

Molecular evolution of the rice miR395 gene family

et al. 2005

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MicroRNAs (miRNAs) are 20-22 nucleotide non-coding RNAs that play important roles in plant and animal development. They are usually processed from larger precursors that can form stem-loop structures. Among 20 miRNA families that are conserved between Arabidopsis and rice, the rice miR395 gene family was unique because it was organized into compact clusters that could be transcribed as one single transcript. We show here that in fact this family had four clusters of total 24 genes. Three of these clusters were segmental duplications. They contained miR395 genes of both 120 bp and 66 bp long. However, only the latter was repeatedly duplicated. The fourth cluster contained miR395 genes of two different sizes that could be the consequences of intergenic recombination of genes from the first three clusters. On each cluster, both 1-duplication and 2-duplication histories were observed based on the sequence similarity between miR395 genes, some of which were nearly identical suggesting a recent origin. This was supported by a miR395 locus survey among several species of the genus Oryza, where two clusters were only found in species with an AA genome, the genome of the cultivated rice. A comparative study of the genomic organization of Medicago truncatula miR395 gene family showed significant expansion of intergenic spaces indicating that the originally clustered genes were drifting away from each other. The diverse genomic organizations of a conserved microRNA gene family in different plant genomes indicated that this important negative gene regulation system has undergone dramatic tune-ups in plant genomes.

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“…Several families of microRNAs (miRNAs) have been found in green plants ranging from algae, mosses, ferns, gymnosperms and angiosperms (Floyd and Bowman, 2004;Arazi et al, 2005;Axtell and Bartel, 2005;Molnár et al, 2007;Zhang et al, 2006;Zhao et al, 2007) suggesting that the regulation by miRNA is ancient in origin. At least 88 annotated miRNA families have been identified in the moss P. patens and 44 in the lycopod Selaginella moellendorffii (Axtell et al, 2007;Fattash et al, 2007).…”

Section: Bryophytes As An Ancient Lineage May Have Retained Many Novementioning

confidence: 99%

Hormonal regulation in green plant lineage families

Johri

2008

Physiol Mol Biol Plants

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The patterns of phytohormones distribution, their native function and possible origin of hormonal regulation across the green plant lineages (chlorophytes, charophytes, bryophytes and tracheophytes) are discussed. The five classical phytohormonesauxins, cytokinins, gibberellins (GA), abscisic acid (ABA) and ethylene occur ubiquitously in green plants. They are produced as secondary metabolites by microorganisms. Some of the bacterial species use phytohormones to interact with the plant as a part of their colonization strategy. Phytohormone biosynthetic pathways in plants seem to be of microbial origin and furthermore, the origin of high affinity perception mechanism could have preceded the recruitment of a metabolite as a hormone. The bryophytes represent the earliest land plants which respond to the phytohormones with the exception of gibberellins. The regulation by auxin and ABA may have evolved before the separation of green algal lineage. Auxin enhances rhizoid and caulonemal differentiation while cytokinins enhance shoot bud formation in mosses. Ethylene retards cell division but seems to promote cell elongation. The presence of responses specific to cytokinins and ethylene strongly suggest the origin of their regulation in bryophytes. The hormonal role of GAs could have evolved in some of the ferns where antheridiogens (compounds related to GAs) and GAs themselves regulate the formation of antheridia.During migration of life forms to land, the tolerance to desiccation may have evolved and is now observed in some of the microorganisms, animals and plants. Besides plants, sequences coding for late embryogenesis abundant-like proteins occur in the genomes of other anhydrobiotic species of microorganisms and nematodes. ABA acts as a stress signal and increases rapidly upon desiccation or in response to some of the abiotic stresses in green plants. As the salt stress also increases ABA release in the culture medium of cyanobacterium Trichormus variabilis, the recruitment of ABA in the regulation of stress responses could have been derived from prokaryotes and present at the level of common ancestor of green plants. The overall hormonal action mechanisms in mosses are remarkably similar to that of the higher plants. As plants are thought to be monophyletic in origin, the existence of remarkably similar hormonal mechanisms in the mosses and higher plants, suggests that some of the basic elements of regulation cascade could have also evolved at the level of common ancestor of plants. The networking of various steps in a cascade or the crosstalk between different cascades is variable and reflects the dynamic interaction between a species and its specific environment.

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Ancient microRNA target sequences in plants

Cited by 374 publications

References 12 publications

Identification of Potential microRNAs and Their Targets in Brassica rapa L.

Identification of Potential microRNAs and Their Targets in Brassica rapa L.

Molecular evolution of the rice miR395 gene family

Hormonal regulation in green plant lineage families

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