scholarly journals Pre-meiotic 21-nucleotide reproductive phasiRNAs emerged in seed plants and diversified in flowering plants

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Suresh Pokhrel ◽  
Kun Huang ◽  
Sébastien Bélanger ◽  
Junpeng Zhan ◽  
Jeffrey L. Caplan ◽  
...  
Keyword(s):  
Gene Expression ◽  
Small Rnas ◽  
Regulatory Elements ◽  
Reproductive Organs ◽  
Anther Development ◽  
Flowering Plants ◽  
Genome Integrity ◽  
Seed Plants ◽  
Small Interfering Rnas ◽  
Fine Tune

AbstractPlant small RNAs are important regulatory elements that fine-tune gene expression and maintain genome integrity by silencing transposons. Reproductive organs of monocots produce abundant phased, small interfering RNAs (phasiRNAs). The 21-nt reproductive phasiRNAs triggered by miR2118 are highly enriched in pre-meiotic anthers, and have been found in multiple eudicot species, in contrast with prior reports of monocot specificity. The 24-nt reproductive phasiRNAs are triggered by miR2275, and are highly enriched during meiosis in many angiosperms. Here, we report the widespread presence of the 21-nt reproductive phasiRNA pathway in eudicots including canonical and non-canonical microRNA (miRNA) triggers of this pathway. In eudicots, these 21-nt phasiRNAs are enriched in pre-meiotic stages, a spatiotemporal distribution consistent with that of monocots and suggesting a role in anther development. Although this pathway is apparently absent in well-studied eudicot families including the Brassicaceae, Solanaceae and Fabaceae, our work in eudicots supports an earlier singular finding in spruce, a gymnosperm, indicating that the pathway of 21-nt reproductive phasiRNAs emerged in seed plants and was lost in some lineages.

scholarly journals Pre-meiotic, 21-nucleotide Reproductive PhasiRNAs Emerged in Seed Plants and Diversified in Flowering Plants

2020 ◽  
Author(s):  
Suresh Pokhrel ◽  
Kun Huang ◽  
Sébastien Bélanger ◽  
Jeffrey L. Caplan ◽  
Elena M. Kramer ◽  
...  
Keyword(s):  
Small Rnas ◽  
Reproductive Development ◽  
Regulatory Elements ◽  
Reproductive Organs ◽  
Anther Development ◽  
Genome Integrity ◽  
Seed Plants ◽  
Small Interfering Rnas ◽  
Wild Strawberry ◽  
Fine Tune

AbstractPlant small RNAs (sRNAs) are important regulatory elements that fine-tune gene expression and maintain genome integrity by silencing transposons. They have critical roles in most pathways involved in plant growth and reproductive development. Reproductive organs of monocots produce abundant phased, small interfering RNAs (phasiRNAs). The 21-nt reproductive phasiRNAs triggered by miR2118 are highly enriched in pre-meiotic anthers, and have not been described in eudicots. The 24-nt reproductive phasiRNAs are triggered by miR2275, and are highly enriched during meiosis in many angiosperms. Here, we describe additional variants of 21-nt reproductive phasiRNAs, including those triggered by miR11308 in wild strawberry, a eudicot, and we validate the presence of this pathway in rose. We report the widespread presence of the 21-nt reproductive phasiRNA pathway in eudicots, with novel biogenesis triggers in the basal eudicot columbine and the rosid flax. In eudicots, these 21-nt phasiRNAs are enriched in pre-meiotic stages, a spatiotemporal distribution consistent with that of monocots and suggesting a role in anther development. Although this pathway is apparently absent in well-studied eudicot families including the Brassicaceae, Solanaceae and Fabaceae, our work in eudicots supports a singular finding in spruce, indicating that the pathway of 21-nt reproductive phasiRNAs emerged in seed plants and was lost in some lineages.

scholarly journals Dicer-like 5 deficiency confers temperature-sensitive male sterility in maize

2018 ◽  
Author(s):  
Chong Teng ◽  
Han Zhang ◽  
Reza Hammond ◽  
Kun Huang ◽  
Blake C. Meyers ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Plant Development ◽  
Small Rnas ◽  
Male Fertility ◽  
Flowering Plants ◽  
Genome Integrity ◽  
Temperature Sensitive ◽  
Small Interfering Rnas ◽  
Transcript Levels ◽  
Tapetal Cells

AbstractSmall RNAs play important roles during plant development by regulating transcript levels of target mRNAs, maintaining genome integrity, and reinforcing DNA methylation. Dicer-like 5 (Dcl5) is proposed to be responsible for precise slicing in many monocots to generate diverse 24-nt phased, secondary small interfering RNAs (phasiRNAs), which are exceptionally abundant in meiotic anthers of diverse flowering plants. The importance and functions of these phasiRNAs remain unclear. Here, we characterized several mutants of dcl5, including alleles generated by the Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) Cas9 system and a transposon-disrupted allele. We report that dcl5 mutants have few or no 24-nt phasiRNAs, develop short anthers with defective tapetal cells, and exhibit temperature-sensitive male fertility. We propose that DCL5 and 24-nt phasiRNAs are critical for fertility under growth regimes for optimal yield.

scholarly journals Nurse cell­–derived small RNAs define paternal epigenetic inheritance in Arabidopsis

Science ◽  
2021 ◽  
Vol 373 (6550) ◽  
pp. eabh0556 ◽  
Author(s):  
Jincheng Long ◽  
James Walker ◽  
Wenjing She ◽  
Billy Aldridge ◽  
Hongbo Gao ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Small Rnas ◽  
De Novo ◽  
Epigenetic Inheritance ◽  
Genome Integrity ◽  
Nurse Cells ◽  
Small Interfering Rnas ◽  
Male Germline ◽  
Methylation Patterns

The plant male germline undergoes DNA methylation reprogramming, which methylates genes de novo and thereby alters gene expression and regulates meiosis. Here, we reveal the molecular mechanism underlying this reprogramming. We demonstrate that genic methylation in the male germline, from meiocytes to sperm, is established by 24-nucleotide small interfering RNAs (siRNAs) transcribed from transposons with imperfect sequence homology. These siRNAs are synthesized by meiocyte nurse cells (tapetum) through activity of CLSY3, a chromatin remodeler absent in other anther cells. Tapetal siRNAs govern germline methylation throughout the genome, including the inherited methylation patterns in sperm. Tapetum-derived siRNAs also silence germline transposons, safeguarding genome integrity. Our results reveal that tapetal siRNAs are sufficient to reconstitute germline methylation patterns and drive functional methylation reprogramming throughout the male germline.

scholarly journals Nurse cell-derived small RNAs define paternal epigenetic inheritance in Arabidopsis

2021 ◽  
Author(s):  
Jincheng Long ◽  
James Walker ◽  
Wenjing She ◽  
Billy Aldridge ◽  
Hongbo Gao ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Small Rnas ◽  
Nurse Cell ◽  
De Novo ◽  
Epigenetic Inheritance ◽  
Genome Integrity ◽  
Nurse Cells ◽  
Male Germline ◽  
Methylation Patterns

AbstractThe plant male germline undergoes DNA methylation reprogramming, which methylates genes de novo and thereby alters gene expression and facilitates meiosis. Why reprogramming is limited to the germline and how specific genes are chosen is unknown. Here, we demonstrate that genic methylation in the male germline, from meiocytes to sperm, is established by germline-specific siRNAs transcribed from transposons with imperfect sequence homology. These siRNAs are synthesized by meiocyte nurse cells (tapetum) via activity of the tapetum-specific chromatin remodeler CLASSY3. Remarkably, tapetal siRNAs govern germline methylation throughout the genome, including the inherited methylation patterns in sperm. Finally, we demonstrate that these nurse cell-derived siRNAs (niRNAs) silence germline transposons, thereby safeguarding genome integrity. Our results reveal that tapetal niRNAs are sufficient to reconstitute germline methylation patterns and drive extensive, functional methylation reprogramming analogous to piRNA-mediated reprogramming in animal germlines.

scholarly journals Small RNAs in parasitic nematodes – forms and functions

Parasitology ◽  
2019 ◽  
Vol 147 (8) ◽  
pp. 855-864
Author(s):  
Collette Britton ◽  
Roz Laing ◽  
Eileen Devaney
Keyword(s):  
Gene Expression ◽  
Small Rna ◽  
Small Rnas ◽  
Target Genes ◽  
Parasitic Nematodes ◽  
Small Rna Sequencing ◽  
Small Interfering Rnas ◽  
Rna Sequences ◽  
C Elegans

AbstractSmall RNAs are important regulators of gene expression. They were first identified in Caenorhabditis elegans, but it is now apparent that the main small RNA silencing pathways are functionally conserved across diverse organisms. Availability of genome data for an increasing number of parasitic nematodes has enabled bioinformatic identification of small RNA sequences. Expression of these in different lifecycle stages is revealed by small RNA sequencing and microarray analysis. In this review we describe what is known of the three main small RNA classes in parasitic nematodes – microRNAs (miRNAs), Piwi-interacting RNAs (piRNAs) and small interfering RNAs (siRNAs) – and their proposed functions. miRNAs regulate development in C. elegans and the temporal expression of parasitic nematode miRNAs suggest modulation of target gene levels as parasites develop within the host. miRNAs are also present in extracellular vesicles released by nematodes in vitro, and in plasma from infected hosts, suggesting potential regulation of host gene expression. Roles of piRNAs and siRNAs in suppressing target genes, including transposable elements, are also reviewed. Recent successes in RNAi-mediated gene silencing, and application of small RNA inhibitors and mimics will continue to advance understanding of small RNA functions within the parasite and at the host–parasite interface.

scholarly journals Multigenerational Regulation of the Caenorhabditis elegans Chromatin Landscape by Germline Small RNAs

2019 ◽  
Vol 53 (1) ◽  
pp. 289-311 ◽  
Author(s):  
Natasha E. Weiser ◽  
John K. Kim
Keyword(s):  
Gene Expression ◽  
Caenorhabditis Elegans ◽  
Small Rnas ◽  
Model Organism ◽  
Epigenetic Inheritance ◽  
Small Interfering Rnas ◽  
Transgenerational Epigenetic Inheritance ◽  
C Elegans ◽  
Small Noncoding Rnas ◽  
Rna Pathways

In animals, small noncoding RNAs that are expressed in the germline and transmitted to progeny control gene expression to promote fertility. Germline-expressed small RNAs, including endogenous small interfering RNAs (endo-siRNAs) and Piwi-interacting RNAs (piRNAs), drive the repression of deleterious transcripts such as transposons, repetitive elements, and pseudogenes. Recent studies have highlighted an important role for small RNAs in transgenerational epigenetic inheritance via regulation of heritable chromatin marks; therefore, small RNAs are thought to convey an epigenetic memory of genomic self and nonself elements. Small RNA pathways are highly conserved in metazoans and have been best described for the model organism Caenorhabditis elegans. In this review, we describe the biogenesis, regulation, and function of C. elegans endo-siRNAs and piRNAs, along with recent insights into how these distinct pathways are integrated to collectively regulate germline gene expression, transgenerational epigenetic inheritance, and ultimately, animal fertility.

scholarly journals Cross-Kingdom Small RNAs Among Animals, Plants and Microbes

Cells ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 371 ◽  
Author(s):  
Zeng ◽  
Gupta ◽  
Jiang ◽  
Yang ◽  
Gong ◽  
...  
Keyword(s):  
Gene Expression ◽  
Rna Interference ◽  
Gene Silencing ◽  
Horizontal Transfer ◽  
Small Rnas ◽  
Signal Transmission ◽  
Fungal Diseases ◽  
Small Interfering Rnas ◽  
Eukaryotic Species ◽  
Non Coding Rnas

Small RNAs (sRNAs), a class of regulatory non-coding RNAs around 20~30-nt long, including small interfering RNAs (siRNAs) and microRNAs (miRNAs), are critical regulators of gene expression. Recently, accumulating evidence indicates that sRNAs can be transferred not only within cells and tissues of individual organisms, but also across different eukaryotic species, serving as a bond connecting the animal, plant, and microbial worlds. In this review, we summarize the results from recent studies on cross-kingdom sRNA communication. We not only review the horizontal transfer of sRNAs among animals, plants and microbes, but also discuss the mechanism of RNA interference (RNAi) signal transmission via cross-kingdom sRNAs. We also compare the advantages of host-induced gene silencing (HIGS) and spray-induced gene silencing (SIGS) technology and look forward to their applicable prospects in controlling fungal diseases.

scholarly journals Widespread roles for piRNAs and WAGO-class siRNAs in shaping the germline transcriptome of Caenorhabditis elegans

2019 ◽  
Vol 48 (4) ◽  
pp. 1811-1827 ◽  
Author(s):  
Kailee J Reed ◽  
Joshua M Svendsen ◽  
Kristen C Brown ◽  
Brooke E Montgomery ◽  
Taylor N Marks ◽  
...  
Keyword(s):  
Gene Expression ◽  
Caenorhabditis Elegans ◽  
Small Rnas ◽  
High Throughput Sequencing ◽  
Critical Role ◽  
Rnai Pathway ◽  
Small Interfering Rnas ◽  
Germline Development ◽  
Histone Mrnas ◽  
High Level

Abstract Piwi-interacting RNAs (piRNAs) and small interfering RNAs (siRNAs) are distinct classes of small RNAs required for proper germline development. To identify the roles of piRNAs and siRNAs in regulating gene expression in Caenorhabditis elegans, we subjected small RNAs and mRNAs from the gonads of piRNA and siRNA defective mutants to high-throughput sequencing. We show that piRNAs and an abundant class of siRNAs known as WAGO-class 22G-RNAs are required for proper expression of spermatogenic and oogenic genes. WAGO-class 22G-RNAs are also broadly required for transposon silencing, whereas piRNAs are largely dispensable. piRNAs, however, have a critical role in controlling histone gene expression. In the absence of piRNAs, histone mRNAs are misrouted into the nuclear RNAi pathway involving the Argonaute HRDE-1, concurrent with a reduction in the expression of many histone mRNAs. We also show that high-level gene expression in the germline is correlated with high level 22G-RNA production. However, most highly expressed genes produce 22G-RNAs through a distinct pathway that presumably involves the Argonaute CSR-1. In contrast, genes targeted by the WAGO branch of the 22G-RNA pathway are typically poorly expressed and respond unpredictably to loss of 22G-RNAs. Our results point to broad roles for piRNAs and siRNAs in controlling gene expression in the C. elegans germline.

scholarly journals Abolished miR158 activity leads to 21-nucleotide tertiary phasiRNA biogenesis that targets NHX2 in Arabidopsis thaliana

2021 ◽  
Author(s):  
Abhinandan Mani Tripathi ◽  
Rajneesh Singh ◽  
Akanksha Singh ◽  
Ashwani Kumar Verma ◽  
Parneeta Mishra ◽  
...  
Keyword(s):  
Gene Expression ◽  
Small Rna ◽  
Small Rnas ◽  
Small Interfering Rnas ◽  
Primary Transcript ◽  
Over Expression ◽  
Additional Layer ◽  
Natural Variants ◽  
Non Coding Rnas

ABSTRACTSmall RNAs including microRNAs (miRNAs) are short 20-24-nucleotide non-coding RNAs. They are key regulators of gene expression in plants and other organisms. Some small RNAs, mostly 22-nucleotide long trigger biogenesis of secondary small interfering RNAs (siRNAs). Those siRNAs having distinctive phased configuration are known as phased siRNAs (phasiRNAs) and act either in cis or trans enhancing silencing cascade. Here, we report natural variants of MIR158 having deletions or insertions led to negligible or reduced expression of miR158. The deletion/insertion events affected processing of primary transcript of miR158 to precursor and to mature miR158. We show that miR158 targets a pseudo-pentatricopeptide gene and its abolished activity led to 21-nucleotide tertiary phasiRNA generation from its target. The biogenesis of these phasiRNAS is triggered by TAS2 derived two siRNAs. Accordingly, small RNA analyses of these natural variants, mutants and over-expression lines of MIR158 or its target exhibited enhanced or reduced phasiRNA biogenesis. Finally, we functionally validated the highest expressed tertiary phasiRNA that targets NHX2 thereby regulating transpiration and stomatal conductance. Overall, we deciphered a new module of small RNA network, miRNA-TAS-siRNA-pseudogene-tertiary phasiRNA-NHX2, suggesting an additional layer of gene regulation and larger role of pseudogene in plants.

scholarly journals Reproductive phasiRNA loci and DICER-LIKE5, but not microRNA loci, diversified in monocotyledonous plants

2020 ◽  
Author(s):  
Parth Patel ◽  
Sandra M. Mathioni ◽  
Reza Hammond ◽  
Alex E. Harkess ◽  
Atul Kakrana ◽  
...  
Keyword(s):  
Gene Duplication ◽  
Small Rna ◽  
Small Rnas ◽  
Flowering Plants ◽  
Small Interfering Rnas ◽  
Large Collection ◽  
Signatures Of Selection ◽  
Selection For ◽  
Grass Genomes

AbstractIn monocots other than maize and rice, the repertoire and diversity of microRNAs (miRNAs) and the populations of phased, secondary, small interfering RNAs (phasiRNAs) are poorly characterized. To remedy this, we sequenced small RNAs from vegetative and dissected inflorescence tissue in 28 phylogenetically diverse monocots and from several early-diverging angiosperm lineages, as well as publicly available data from 10 additional monocot species. We annotated miRNAs, siRNAs and phasiRNAs across the monocot phylogeny, identifying miRNAs apparently lost or gained in the grasses relative to other monocot families, as well as a number of tRNA fragments misannotated as miRNAs. Using our miRNA database cleaned of these misannotations, we identified conservation at the 8th, 9th, 19th and 3’ end positions that we hypothesize are signatures of selection for processing, targeting, or Argonaute sorting. We show that 21-nt reproductive phasiRNAs are far more numerous in grass genomes than other monocots. Based on sequenced monocot genomes and transcriptomes, DICER-LIKE5 (DCL5), important to 24-nt phasiRNA biogenesis, likely originated via gene duplication before the diversification of the grasses. This curated database of phylogenetically diverse monocot miRNAs, siRNAs, and phasiRNAs represents a large collection of data that should facilitate continued exploration of small RNA diversification in flowering plants.

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