MicroRNAs from the parasitic plant Cuscuta campestris target host messenger RNAs

First paragraphDodders (Cuscuta spp.) are obligate parasitic plants that obtain water and nutrients from the stems of host plants via specialized feeding structures called haustoria. Dodder haustoria facilitate bi-directional movement of viruses, proteins, and mRNAs between host and parasite1, but the functional effects of these movements are not clear. Here we show that C. campestris haustoria accumulate high levels of many novel microRNAs (miRNAs) while parasitizing Arabidopsis thaliana hosts. Many of these miRNAs are 22 nts long, a usually rare size of plant miRNA associated with amplification of target silencing through secondary small interfering RNA (siRNA) production2. Several A. thaliana mRNAs are targeted by C. campestris 22 nt miRNAs during parasitism, resulting in mRNA cleavage, secondary siRNA production, and decreased mRNA accumulation levels. Hosts with mutations in two of the targets supported significantly higher growth of C. campestris. Homologs of target mRNAs from diverse plants also have predicted target sites to induced C. campestris miRNAs, and the same miRNAs are expressed and active against host targets when C. campestris parasitizes a different host, Nicotiana benthamiana. These data show that C. campestris miRNAs act as trans-species regulators of host gene expression, and suggest that they may act as virulence factors during parasitism.

Download Full-text

Search for Resistant Genotypes to Cuscuta campestris Infection in Two Legume Species, Vicia sativa and Vicia ervilia

Plants ◽

10.3390/plants10040738 ◽

2021 ◽

Vol 10 (4) ◽

pp. 738

Author(s):

Eva María Córdoba ◽

Mónica Fernández-Aparicio ◽

Clara Isabel González-Verdejo ◽

Carmela López-Grau ◽

María del Valle Muñoz-Muñoz ◽

...

Keyword(s):

Agricultural Production ◽

Host Plants ◽

Resistance Breeding ◽

Parasitic Plants ◽

Vicia Sativa ◽

Common Vetch ◽

Germplasm Collections ◽

Bitter Vetch ◽

Cuscuta Campestris ◽

Resistant Genotypes

The dodders (Cuscuta spp.) are parasitic plants that feed on the stems of their host plants. Cuscuta campestris is one of the most damaging parasitic plants for the worldwide agricultural production of broad-leaved crops. Its control is limited or non-existent, therefore resistance breeding is the best alternative both economically and environmentally. Common vetch (Vicia sativa) and bitter vetch (Vicia ervilia) are highly susceptible to C. campestris, but no resistant genotypes have been identified. Thus, the aim of this study was to identify in V. sativa and V.ervilia germplasm collections genotypes resistant to C. campestris infection for use in combating this parasitic plant. Three greenhouse screening were conducted to: (1) identify resistant responses in a collection of 154 accessions of bitter vetch and a collection of 135 accessions of common vetch genotypes against infection of C. campestris; (2) confirm the resistant response identified in common vetch accessions; and (3) characterize the effect of C. campestris infection on biomass of V. sativa resistant and susceptible accessions. Most common vetch and bitter vetch genotypes tested were susceptible to C. campestris. However, the V. sativa genotype Vs.1 exhibited high resistance. The resistant phenotype was characterized by a delay in the development of C. campestris posthaustorial growth and a darkening resembling a hypersensitive-like response at the penetration site. The resistant mechanism was effective in limiting the growth of C. campestris as the ratio of parasite/host shoot dry biomass was more significantly reduced than the rest of the accessions. To the best or our knowledge, this is the first identification of Cuscuta resistance in V. sativa genotypes.

Download Full-text

Muscle-specific microRNA miR-206 promotes muscle differentiation

The Journal of Cell Biology ◽

10.1083/jcb.200603008 ◽

2006 ◽

Vol 174 (5) ◽

pp. 677-687 ◽

Cited By ~ 523

Author(s):

Hak Kyun Kim ◽

Yong Sun Lee ◽

Umasundari Sivaprasad ◽

Ankit Malhotra ◽

Anindya Dutta

Keyword(s):

Antisense Oligonucleotide ◽

Small Interfering Rna ◽

Degradation Process ◽

Microrna Target ◽

C2c12 Myoblasts ◽

Target Sites ◽

The Many ◽

Interfering Rna ◽

In Vitro Transfection

Three muscle-specific microRNAs, miR-206, -1, and -133, are induced during differentiation of C2C12 myoblasts in vitro. Transfection of miR-206 promotes differentiation despite the presence of serum, whereas inhibition of the microRNA by antisense oligonucleotide inhibits cell cycle withdrawal and differentiation, which are normally induced by serum deprivation. Among the many mRNAs that are down-regulated by miR-206, the p180 subunit of DNA polymerase α and three other genes are shown to be direct targets. Down-regulation of the polymerase inhibits DNA synthesis, an important component of the differentiation program. The direct targets are decreased by mRNA cleavage that is dependent on predicted microRNA target sites. Unlike small interfering RNA–directed cleavage, however, the 5′ ends of the cleavage fragments are distributed and not confined to the target sites, suggesting involvement of exonucleases in the degradation process. In addition, inhibitors of myogenic transcription factors, Id1-3 and MyoR, are decreased upon miR-206 introduction, suggesting the presence of additional mechanisms by which microRNAs enforce the differentiation program.

Download Full-text

Lack of pairing during meiosis triggers multigenerational transgene silencing in Caenorhabditis elegans

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1501979112 ◽

2015 ◽

Vol 112 (20) ◽

pp. E2667-E2676 ◽

Cited By ~ 16

Author(s):

Luciana E. Leopold ◽

Bree N. Heestand ◽

Soobin Seong ◽

Ludmila Shtessel ◽

Shawn Ahmed

Keyword(s):

Caenorhabditis Elegans ◽

Small Rna ◽

Transgene Expression ◽

Single Copy ◽

Transgene Silencing ◽

Meiotic Pairing ◽

Homologous Chromosomes ◽

Diverse Species ◽

Secondary Sirna ◽

Interfering Rna

Single-copy transgenes in Caenorhabditis elegans can be subjected to a potent, irreversible silencing process termed small RNA-induced epigenetic silencing (RNAe). RNAe is promoted by the Piwi Argonaute protein PRG-1 and associated Piwi-interacting RNAs (piRNAs), as well as by proteins that promote and respond to secondary small interfering RNA (siRNA) production. Here we define a related siRNA-mediated silencing process, termed “multigenerational RNAe,” which can occur for transgenes that are maintained in a hemizygous state for several generations. We found that transgenes that contain either GFP or mCherry epitope tags can be silenced via multigenerational RNAe, whereas a transgene that possesses GFP and a perfect piRNA target site can be rapidly and permanently silenced via RNAe. Although previous studies have shown that PRG-1 is typically dispensable for maintenance of RNAe, we found that both initiation and maintenance of multigenerational RNAe requires PRG-1 and the secondary siRNA biogenesis protein RDE-2. Although silencing via RNAe is irreversible, we found that transgene expression can be restored when hemizygous transgenes that were silenced via multigenerational RNAe become homozygous. Furthermore, multigenerational RNAe was accelerated when meiotic pairing of the chromosome possessing the transgene was abolished. We propose that persistent lack of pairing during meiosis elicits a reversible multigenerational silencing response, which can lead to permanent transgene silencing. Multigenerational RNAe may be broadly relevant to single-copy transgenes used in experimental biology and to shaping the epigenomic landscape of diverse species, where genomic polymorphisms between homologous chromosomes commonly result in unpaired DNA during meiosis.

Download Full-text

Vehicles for Small Interfering RNA transfection: Exosomes versus Synthetic Nanocarriers

DNA and RNA Nanotechnology ◽

10.2478/rnan-2013-0002 ◽

2013 ◽

Vol 1 (1) ◽

Cited By ~ 3

Author(s):

Markus Duechler

Keyword(s):

Small Rnas ◽

Sirna Delivery ◽

Target Cells ◽

Messenger Rnas ◽

Small Interfering Rnas ◽

Rna Transfection ◽

Efficient Delivery ◽

Micro Rnas ◽

Delivery Vehicles ◽

Interfering Rna

AbstractTherapies based on RNA interference (RNAi) hold a great potential for targeted interference of the expression of specific genes. Small-interfering RNAs (siRNA) and micro-RNAs interrupt protein synthesis by inducing the degradation of messenger RNAs or by blocking their translation. RNAibased therapies can modulate the expression of otherwise undruggable target proteins. Full exploitation of RNAi for medical purposes depends on efficient and safe methods for delivery of small RNAs to the target cells. Tremendous effort has gone into the development of synthetic carriers to meet all requirements for efficient delivery of nucleic acids into particular tissues. Recently, exosomes unveiled their function as a natural communication system which can be utilized for the transport of small RNAs into target cells. In this review, the capabilities of exosomes as delivery vehicles for small RNAs are compared to synthetic carrier systems. The step by step requirements for efficient transfection are considered: production of the vehicle, RNA loading, protection against degradation, lack of immunogenicity, targeting possibilities, cellular uptake, cytotoxicity, RNA release into the cytoplasm and gene silencing efficiency. An exosomebased siRNA delivery system shows many advantages over conventional transfection agents, however, some crucial issues need further optimization before broad clinical application can be realized.

Download Full-text

Translational Repression and eIF4A2 Activity Are Critical for MicroRNA-Mediated Gene Regulation

Science ◽

10.1126/science.1231197 ◽

2013 ◽

Vol 340 (6128) ◽

pp. 82-85 ◽

Cited By ~ 211

Author(s):

H. A. Meijer ◽

Y. W. Kong ◽

W. T. Lu ◽

A. Wilczynska ◽

R. V. Spriggs ◽

...

Keyword(s):

Gene Regulation ◽

Molecular Mechanisms ◽

Translational Repression ◽

Messenger Rnas ◽

Primary Event ◽

Control Gene Expression ◽

Target Sites ◽

Key Factor ◽

Mrna Destabilization ◽

Translational Inhibition

MicroRNAs (miRNAs) control gene expression through both translational repression and degradation of target messenger RNAs (mRNAs). However, the interplay between these processes and the precise molecular mechanisms involved remain unclear. Here, we show that translational inhibition is the primary event required for mRNA degradation. Translational inhibition depends on miRNAs impairing the function of the eIF4F initiation complex. We define the RNA helicase eIF4A2 as the key factor of eIF4F through which miRNAs function. We uncover a correlation between the presence of miRNA target sites in the 3′ untranslated region (3′UTR) of mRNAs and secondary structure in the 5′UTR and show that mRNAs with unstructured 5′UTRs are refractory to miRNA repression. These data support a linear model for miRNA-mediated gene regulation in which translational repression via eIF4A2 is required first, followed by mRNA destabilization.

Download Full-text

Multiple Regulators of Ty1 Transposition in Saccharomyces cerevisiae Have Conserved Roles in Genome Maintenance

Genetics ◽

10.1093/genetics/159.4.1449 ◽

2001 ◽

Vol 159 (4) ◽

pp. 1449-1465 ◽

Cited By ~ 4

Author(s):

Derek T Scholes ◽

Mukti Banerjee ◽

Brian Bowen ◽

M Joan Curcio

Keyword(s):

Saccharomyces Cerevisiae ◽

Trna Genes ◽

Gene Products ◽

Genome Maintenance ◽

Mrna Accumulation ◽

Target Sites ◽

Ty1 Mobility ◽

Cdna Integration ◽

Rna Levels

Abstract Most Ty1 retrotransposons in the genome of Saccharomyces cerevisiae are transpositionally competent but rarely transpose. We screened yeast mutagenized by insertion of the mTn3-lacZ/LEU2 transposon for mutations that result in elevated Ty1 cDNA-mediated mobility, which occurs by cDNA integration or recombination. Here, we describe the characterization of mTn3 insertions in 21 RTT (regulation of Ty1 transposition) genes that result in 5- to 111-fold increases in Ty1 mobility. These 21 RTT genes are EST2, RRM3, NUT2, RAD57, RRD2, RAD50, SGS1, TEL1, SAE2, MED1, MRE11, SCH9, KAP122, and 8 previously uncharacterized genes. Disruption of RTT genes did not significantly increase Ty1 RNA levels but did enhance Ty1 cDNA levels, suggesting that most RTT gene products act at a step after mRNA accumulation but before cDNA integration. The rtt mutations had widely varying effects on integration of Ty1 at preferred target sites. Mutations in RTT101 and NUT2 dramatically stimulated Ty1 integration upstream of tRNA genes. In contrast, a mutation in RRM3 increased Ty1 mobility >100-fold without increasing integration upstream of tRNA genes. The regulation of Ty1 transposition by components of fundamental pathways required for genome maintenance suggests that Ty1 and yeast have coevolved to link transpositional dormancy to the integrity of the genome.

Download Full-text

Parasitism-evoked horizontal gene transfer between plants as a novel trigger for specialized metabolism evolution

10.21203/rs.3.rs-885568/v1 ◽

2021 ◽

Author(s):

Eiichiro Ono ◽

Kohki Shimizu ◽

Jun Murata ◽

Akira Shiraishi ◽

Ryusuke Yokoyama ◽

...

Keyword(s):

Gene Transfer ◽

Horizontal Gene Transfer ◽

Host Plants ◽

Molecular Mechanisms ◽

Sequence Similarity ◽

Metabolic Evolution ◽

Apparent Lack ◽

Cuscuta Campestris ◽

Genomic Studies ◽

Biological Impacts

Abstract Recent genomic studies of parasitic plants have revealed that there are numerous footprints indicative of horizontal gene transfer (HGT) to the parasites from their host plants. However, the molecular mechanisms and biological impacts of this phenomenon have remained largely unknown. Here, we made the striking observation that two parasitic dodders, Cuscuta campestris and C. australis, have functional homologues of Si_CYP81Q1, which encodes piperitol/sesamin synthase (PSS) in the phylogenetically remote plant Sesamum indicum (sesame). The apparent lack of sequence similarity between the regions flanking PSS in Sesamum and Cuscuta spp. suggests the occurrence of HGT tightly associated with the PSS gene. Upon parasitism, C. campestris induced expression of the host Si_CYP81Q1 at the parasitic interface and mature and intron-retained Si_CYP81Q1 mRNA was transferred to C. campestris, suggesting that CYP81Q1 was translocated via RNA-mediated HGT. Thus, parasitism-evoked HGT might have had an unexpected role in the metabolic evolution of plants.

Download Full-text