Bypassing Iron Storage in Endodermal Vacuoles Rescues the Iron Mobilization Defect in the Natural Resistance Associated-Macrophage Protein3natural Resistance Associated-Macrophage Protein4 Double Mutant

To improve seed iron (Fe) content and bioavailability, it is crucial to decipher the mechanisms that control Fe storage during seed development. In Arabidopsis (Arabidopsis thaliana) seeds, most Fe is concentrated in insoluble precipitates, with phytate in the vacuoles of cells surrounding the vasculature of the embryo. NATURAL RESISTANCE ASSOCIATED-MACROPHAGE PROTEIN3 (AtNRAMP3) and AtNRAMP4 function redundantly in Fe retrieval from vacuoles during germination. When germinated under Fe-deficient conditions, development of the nramp3nramp4 double mutant is arrested as a consequence of impaired Fe mobilization. To identify novel genes involved in seed Fe homeostasis, we screened an ethyl methanesulfonate-mutagenized population of nramp3nramp4 seedlings for mutations suppressing their phenotypes on low Fe. Here, we report that, among the suppressors, two independent mutations in the VACUOLAR IRON TRANSPORTER1 (AtVIT1) gene caused the suppressor phenotype. The AtVIT1 transporter is involved in Fe influx into vacuoles of endodermal and bundle sheath cells. This result establishes a functional link between Fe loading in vacuoles by AtVIT1 and its remobilization by AtNRAMP3 and AtNRAMP4. Moreover, analysis of subcellular Fe localization indicates that simultaneous disruption of AtVIT1, AtNRAMP3, and AtNRAMP4 limits Fe accumulation in vacuolar globoids

Thioredoxin Glutathione Reductase as a Novel Drug Target: Evidence from Schistosoma japonicum

Background: Schistosomiasis remains a major public health concern affecting billions of people around the world. Currently, praziquantel is the only drug of choice for treatment of human schistosomiasis. The emergence of drug resistance to praziquantel in schistosomes makes the development of novel drugs an urgent task. Thioredoxin glutathione reductase (TGR) enzymes in Schistosoma mansoni and some other platyhelminths have been identified as alternative targets. The present study was designed to confirm the existense and the potential value of TGR as a target for development of novel antischistosomal agents in Schistosoma japonicum, a platyhelminth endemic in Asia. Methods and Findings: After cloning the S. japonicum TGR (SjTGR) gene, the recombinant SjTGR selenoprotein was purified and characterized in enzymatic assays as a multifunctional enzyme with thioredoxin reductase (TrxR), glutathione reductase (GR) and glutaredoxin (Grx) activities. Immunological and bioinformatic analyses confirmed that instead of having separate TrxR and GR proteins in mammalian, S. japonicum only encodes TGR, which performs the functions of both enzymes and plays a critical role in maintaining the redox balance in this parasite. These results were in good agreement with previous findings in Schistosoma mansoni and some other platyhelminths. Auranofin, a known inhibitor against TGR, caused fatal toxicity in S. japonicum adult worms in vitro and reduced worm and egg burdens in S. japonicum infected mice. Conclusions: Collectively, our study confirms that a multifunctional enzyme SjTGR selenoprotein, instead of separate Trx

A computational-based update on microRNAs and their targets in barley (Hordeum vulgare L.)

<p>Abstract</p> <p>Background</p> <p>Many plant species have been investigated in the last years for the identification and characterization of the corresponding miRNAs, nevertheless extensive studies are not yet available on barley (at the time of this writing). To extend and to update information on miRNAs and their targets in barley and to identify candidate polymorphisms at miRNA target sites, the features of previously known plant miRNAs have been used to systematically search for barley miRNA homologues and targets in the publicly available ESTs database. Matching sequences have then been related to Unigene clusters on which most of this study was based.</p> <p>Results</p> <p>One hundred-fifty-six microRNA mature sequences belonging to 50 miRNA families have been found to significantly match at least one EST sequence in barley. As expected on the basis of phylogenetic relations, miRNAs putatively orthologous to those of <it>Triticum </it>are significantly over-represented inside the set of identified barley microRNA mature sequences. Many previously known and several putatively new miRNA/target pairs have been identified. When the predicted microRNA targets were grouped into functional categories, biological processes previously known to be regulated by miRNAs, such as development and response to biotic and abiotic stress, have been highlighted and most of the target molecular functions were related to transcription regulation. Candidate microRNA coding genes have been reported and genetic variation (SNPs/indels) both in functional regions of putative miRNAs (mature sequence) and at miRNA target sites has been found.</p> <p>Conclusions</p> <p>This study has provided an update of the information on barley miRNAs and their targets representing a foundation for future studies. Many of previously known plant microRNAs have homologues in barley with expected important roles during development, nutrient deprivation, biotic and abiotic stress response and other important physiological processes. Putative polymorphisms at miRNA target sites have been identified and they can represent an interesting source for the identification of functional genetic variability.</p

A new vesicle trafficking regulator CTL1 plays a crucial role in ion homeostasis

Ion homeostasis is essential for plant growth and environmental adaptation, and maintaining ion homeostasis requires the precise regulation of various ion transporters, as well as correct root patterning. However, the mechanisms underlying these processes remain largely elusive. Here, we reported that a choline transporter gene, CTL1, controls ionome homeostasis by regulating the secretory trafficking of proteins required for plasmodesmata (PD) development, as well as the transport of some ion transporters. Map-based cloning studies revealed that CTL1 mutations alter the ion profile of Arabidopsis thaliana. We found that the phenotypes associated with these mutations are caused by a combination of PD defects and ion transporter misregulation. We also established that CTL1 is involved in regulating vesicle trafficking and is thus required for the trafficking of proteins essential for ion transport and PD development. Characterizing choline transporter-like 1 (CTL1) as a new regulator of protein sorting may enable researchers to understand not only ion homeostasis in plants but also vesicle trafficking in general

A Conserved PHD Finger Protein and Endogenous RNAi Modulate Insulin Signaling in Caenorhabditis elegans

Insulin signaling has a profound effect on longevity and the oxidative stress resistance of animals. Inhibition of insulin signaling results in the activation of DAF-16/FOXO and SKN-1/Nrf transcription factors and increased animal fitness. By studying the biological functions of the endogenous RNA interference factor RDE-4 and conserved PHD zinc finger protein ZFP-1 (AF10), which regulate overlapping sets of genes in Caenorhabditis elegans, we identified an important role for these factors in the negative modulation of transcription of the insulin/PI3 signaling-dependent kinase PDK-1. Consistently, increased expression of pdk-1 in zfp-1 and rde-4 mutants contributed to their reduced lifespan and sensitivity to oxidative stress and pathogens due to the reduction in the expression of DAF-16 and SKN-1 targets. We found that the function of ZFP-1 in modulating pdk-1 transcription was important for the extended lifespan of the age-1(hx546) reduction-of-function PI3 kinase mutant, since the lifespan of the age-1; zfp-1 double mutant strain was significantly shorter compared to age-1(hx546). We further demonstrate that overexpression of ZFP-1 caused an increased resistance to oxidative stress in a DAF-16–dependent manner. Our findings suggest that epigenetic regulation of key upstream signaling components in signal transduction pathways through chromatin and RNAi may have a large impact on the outcome of signaling and expression of numerous downstream genes.Leukemia & Lymphoma Society of America (3260-07 Special Fellow Award)Arnold and Mabel Beckman Foundation (Young Investigator Award)United States. National Institutes of Health (Director's New Innovator Award (1 DP2 OD006412-01))United States. National Institutes of Health (grant GM66269)modENCODE (grant U01 HG004270)United States. National Institutes of Health (training grant 5T32 GM07088-34

A transcriptomic analysis of Echinococcus granulosus larval stages:implications for parasite biology and host adaptation

The cestode Echinococcus granulosus--the agent of cystic echinococcosis, a zoonosis affecting humans and domestic animals worldwide--is an excellent model for the study of host-parasite cross-talk that interfaces with two mammalian hosts. To develop the molecular analysis of these interactions, we carried out an EST survey of E. granulosus larval stages. We report the salient features of this study with a focus on genes reflecting physiological adaptations of different parasite stages.We generated ~10,000 ESTs from two sets of full-length enriched libraries (derived from oligo-capped and trans-spliced cDNAs) prepared with three parasite materials: hydatid cyst wall, larval worms (protoscoleces), and pepsin/H(+)-activated protoscoleces. The ESTs were clustered into 2700 distinct gene products. In the context of the biology of E. granulosus, our analyses reveal: (i) a diverse group of abundant long non-protein coding transcripts showing homology to a middle repetitive element (EgBRep) that could either be active molecular species or represent precursors of small RNAs (like piRNAs); (ii) an up-regulation of fermentative pathways in the tissue of the cyst wall; (iii) highly expressed thiol- and selenol-dependent antioxidant enzyme targets of thioredoxin glutathione reductase, the functional hub of redox metabolism in parasitic flatworms; (iv) candidate apomucins for the external layer of the tissue-dwelling hydatid cyst, a mucin-rich structure that is critical for survival in the intermediate host; (v) a set of tetraspanins, a protein family that appears to have expanded in the cestode lineage; and (vi) a set of platyhelminth-specific gene products that may offer targets for novel pan-platyhelminth drug development.This survey has greatly increased the quality and the quantity of the molecular information on E. granulosus and constitutes a valuable resource for gene prediction on the parasite genome and for further genomic and proteomic analyses focused on cestodes and platyhelminths

Epi-fingerprinting and epi-interventions for improved crop production and food quality

Increasing crop production at a time of rapid climate change represents the greatest challenge facing contemporary agricultural research. Our understanding of the genetic control of yield derives from controlled field experiments designed to minimise environmental variance. In spite of these efforts there is substantial residual variability among plants attributable to Genotype x Environment (GxE) interactions. Recent advances in the field of epigenetics have revealed a plethora of gene control mechanisms that could account for much of this unassigned variation. These systems act as a regulatory interface between the perception of the environment and associated alterations in gene expression. Direct intervention of epigenetic control systems hold the enticing promise of creating new sources of variability that could enhance crop performance. Equally, understanding the relationship between various epigenetic states and responses of the crop to specific aspects of the growing environment (epigenetic fingerprinting) could allow for a more tailored approach to plant agronomy. In this review, we explore the many ways in which epigenetic interventions and epigenetic fingerprinting can be deployed for the improvement of crop production and quality

Plant ARGONAUTEs: Features, Functions and Unknowns

ARGONAUTEs (AGOs) are the effector proteins in eukaryotic small RNA(sRNA)– based gene silencing pathways controlling gene expression and transposon activity. In plants, AGOs regulate key biological processes such as development, response to stress, genome structure and integrity, and pathogen defense. Canonical functions of plant AGO–sRNA complexes include the endonucleolytic cleavage or translational inhibition of target RNAs, and the methylation of target DNAs. Here, I provide a brief update on the major features, molecular functions and biological roles of plant AGOs. A special focus is given to the more recent discoveries related to emerging molecular or biological functions of plant AGOs, as well as to the major unknowns in the plant AGO field.This work was supported by an Individual Fellowship from the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement No. 655841 to A.C.Carbonell Olivares, A. (2017). Plant ARGONAUTEs: Features, Functions and Unknowns. En Plant Argonaute Proteins: Methods and Protocols. Springer Link. 1-21. https://doi.org/10.1007/978-1-4939-7165-7_1121Meister G (2013) Argonaute proteins: functional insights and emerging roles. Nat Rev Genet 14(7):447–459. doi: 10.1038/nrg3462Huntzinger E, Izaurralde E (2011) Gene silencing by microRNAs: contributions of translational repression and mRNA decay. Nat Rev Genet 12(2):99–110. doi: 10.1038/nrg2936Cerutti H, Casas-Mollano JA (2006) On the origin and functions of RNA-mediated silencing: from protists to man. Curr Genet 50(2):81–99. doi: 10.1007/s00294-006-0078-xFang X, Qi Y (2016) RNAi in plants: an argonaute-centered view. Plant Cell 28(2):272–285. doi: 10.1105/tpc1500920Kapoor M, Arora R, Lama T, Nijhawan A, Khurana JP, Tyagi AK, Kapoor S (2008) Genome-wide identification, organization and phylogenetic analysis of Dicer-like, Argonaute and RNA-dependent RNA polymerase gene families and their expression analysis during reproductive development and stress in rice. BMC Genomics 9:451. doi: 10.1186/1471-2164-9-451Morel JB, Godon C, Mourrain P, Beclin C, Boutet S, Feuerbach F, Proux F, Vaucheret H (2002) Fertile hypomorphic ARGONAUTE (ago1) mutants impaired in post-transcriptional gene silencing and virus resistance. Plant Cell 14(3):629–639. doi: 10.1105/tpc010358Yamasaki T, Kim EJ, Cerutti H, Ohama T (2016) Argonaute3 is a key player in miRNA-mediated target cleavage and translational repression in Chlamydomonas. Plant J 85(2):258–268. doi: 10.1111/tpj13107Schroda M (2006) RNA silencing in Chlamydomonas: mechanisms and tools. Curr Genet 49(2):69–84. doi: 10.1007/s00294-005-0042-1Arif MA, Frank W, Khraiwesh B (2013) Role of RNA interference (RNAi) in the moss Physcomitrella patens. Int J Mol Sci 14(1):1516–1540. doi: 10.3390/ijms14011516Zhang H, Xia R, Meyers BC, Walbot V (2015) Evolution, functions, and mysteries of plant ARGONAUTE proteins. Curr Opin Plant Biol 27:84–90. doi: 10.1016/jpbi201506011Chapman EJ, Carrington JC (2007) Specialization and evolution of endogenous small RNA pathways. Nat Rev Genet 8(11):884–896. doi: 10.1038/nrg2179Tolia NH, Joshua-Tor L (2007) Slicer and the argonautes. Nat Chem Biol 3(1):36–43. doi: 10.1038/nchembio848Song JJ, Smith SK, Hannon GJ, Joshua-Tor L (2004) Crystal structure of Argonaute and its implications for RISC slicer activity. Science 305(5689):1434–1437. doi: 10.1126/science1102514Nakanishi K, Weinberg DE, Bartel DP, Patel DJ (2012) Structure of yeast Argonaute with guide RNA. Nature 486(7403):368–374. doi: 10.1038/nature11211Montgomery TA, Howell MD, Cuperus JT, Li D, Hansen JE, Alexander AL, Chapman EJ, Fahlgren N, Allen E, Carrington JC (2008) Specificity of ARGONAUTE7-miR390 interaction and dual functionality in TAS3 trans-acting siRNA formation. Cell 133(1):128–141. doi: 10.1016/jcell200802033Mi S, Cai T, Hu Y, Chen Y, Hodges E, Ni F, Wu L, Li S, Zhou H, Long C, Chen S, Hannon GJ, Qi Y (2008) Sorting of small RNAs into Arabidopsis Argonaute complexes is directed by the 5′ terminal nucleotide. Cell 133(1):116–127. doi: 10.1016/jcell200802034Takeda A, Iwasaki S, Watanabe T, Utsumi M, Watanabe Y (2008) The mechanism selecting the guide strand from small RNA duplexes is different among argonaute proteins. Plant Cell Physiol 49(4):493–500. doi: 10.1093/pcp/pcn043Zhu H, Hu F, Wang R, Zhou X, Sze SH, Liou LW, Barefoot A, Dickman M, Zhang X (2011) Arabidopsis Argonaute10 specifically sequesters miR166/165 to regulate shoot apical meristem development. Cell 145(2):242–256. doi: 10.1016/jcell201103024Zhang X, Niu D, Carbonell A, Wang A, Lee A, Tun V, Wang Z, Carrington JC, Chang CE, Jin H (2014) ARGONAUTE PIWI domain and microRNA duplex structure regulate small RNA sorting in Arabidopsis. Nat Commun 5:5468. doi: 10.1038/ncomms6468Liu J, Carmell MA, Rivas FV, Marsden CG, Thomson JM, Song JJ, Hammond SM, Joshua-Tor L, Hannon GJ (2004) Argonaute2 is the catalytic engine of mammalian RNAi. Science 305(5689):1437–1441. doi: 10.1126/science1102513Sheng G, Zhao H, Wang J, Rao Y, Tian W, Swarts DC, van der Oost J, Patel DJ, Wang Y (2014) Structure-based cleavage mechanism of Thermus thermophilus Argonaute DNA guide strand-mediated DNA target cleavage. Proc Natl Acad Sci U S A 111(2):652–657. doi: 10.1073/pnas1321032111Baumberger N, Baulcombe DC (2005) Arabidopsis ARGONAUTE1 is an RNA slicer that selectively recruits microRNAs and short interfering RNAs. Proc Natl Acad Sci U S A 102(33):11928–11933. doi: 10.1073/pnas0505461102Qi Y, Denli AM, Hannon GJ (2005) Biochemical specialization within Arabidopsis RNA silencing pathways. Mol Cell 19(3):421–428. doi: 10.1016/jmolcel200506014Carbonell A, Fahlgren N, Garcia-Ruiz H, Gilbert KB, Montgomery TA, Nguyen T, Cuperus JT, Carrington JC (2012) Functional analysis of three Arabidopsis ARGONAUTES using slicer-defective mutants. Plant Cell 24(9):3613–3629. doi: 10.1105/tpc112099945Qi Y, He X, Wang XJ, Kohany O, Jurka J, Hannon GJ (2006) Distinct catalytic and non-catalytic roles of ARGONAUTE4 in RNA-directed DNA methylation. Nature 443(7114):1008–1012. doi: 10.1038/nature05198Ji L, Liu X, Yan J, Wang W, Yumul RE, Kim YJ, Dinh TT, Liu J, Cui X, Zheng B, Agarwal M, Liu C, Cao X, Tang G, Chen X (2011) ARGONAUTE10 and ARGONAUTE1 regulate the termination of floral stem cells through two microRNAs in Arabidopsis. PLoS Genet 7(3):e1001358. doi: 10.1371/journalpgen1001358Llave C, Xie Z, Kasschau KD, Carrington JC (2002) Cleavage of Scarecrow-like mRNA targets directed by a class of Arabidopsis miRNA. Science 297(5589):2053–2056. doi: 10.1126/science1076311Rhoades MW, Reinhart BJ, Lim LP, Burge CB, Bartel B, Bartel DP (2002) Prediction of plant microRNA targets. Cell 110(4):513–520. doi: 10.1016/S0092-8674(02)00863-2Mallory AC, Reinhart BJ, Jones-Rhoades MW, Tang G, Zamore PD, Barton MK, Bartel DP (2004) MicroRNA control of PHABULOSA in leaf development: importance of pairing to the microRNA 5′ region. EMBO J 23(16):3356–3364. doi: 10.1038/sjemboj7600340German MA, Pillay M, Jeong DH, Hetawal A, Luo S, Janardhanan P, Kannan V, Rymarquis LA, Nobuta K, German R, De Paoli E, Lu C, Schroth G, Meyers BC, Green PJ (2008) Global identification of microRNA-target RNA pairs by parallel analysis of RNA ends. Nat Biotechnol 26(8):941–946. doi: 10.1038/nbt1417Addo-Quaye C, Eshoo TW, Bartel DP, Axtell MJ (2008) Endogenous siRNA and miRNA targets identified by sequencing of the Arabidopsis degradome. Curr Biol 18(10):758–762. doi: 10.1016/jcub200804042Arribas-Hernandez L, Kielpinski LJ, Brodersen P (2016) mRNA decay of most Arabidopsis miRNA targets requires slicer activity of AGO1. Plant Physiol 171(4):2620–2632. doi: 10.1104/pp.16.00231Cuperus JT, Carbonell A, Fahlgren N, Garcia-Ruiz H, Burke RT, Takeda A, Sullivan CM, Gilbert SD, Montgomery TA, Carrington JC (2010) Unique functionality of 22-nt miRNAs in triggering RDR6-dependent siRNA biogenesis from target transcripts in Arabidopsis. Nat Struct Mol Biol 17(8):997–1003. doi: 10.1038/nsmb1866Montgomery TA, Yoo SJ, Fahlgren N, Gilbert SD, Howell MD, Sullivan CM, Alexander A, Nguyen G, Allen E, Ahn JH, Carrington JC (2008) AGO1-miR173 complex initiates phased siRNA formation in plants. Proc Natl Acad Sci U S A 105(51):20055–20062. doi: 10.1073/pnas0810241105Allen E, Xie Z, Gustafson AM, Carrington JC (2005) microRNA-directed phasing during trans-acting siRNA biogenesis in plants. Cell 121(2):207–221. doi: 10.1016/jcell200504004Yoshikawa M, Peragine A, Park MY, Poethig RS (2005) A pathway for the biogenesis of trans-acting siRNAs in Arabidopsis. Genes Dev 19(18):2164–2175. doi: 10.1101/gad1352605Rajagopalan R, Vaucheret H, Trejo J, Bartel DP (2006) A diverse and evolutionarily fluid set of microRNAs in Arabidopsis thaliana. Genes Dev 20(24):3407–3425. doi: 10.1101/gad1476406Arribas-Hernandez L, Marchais A, Poulsen C, Haase B, Hauptmann J, Benes V, Meister G, Brodersen P (2016) The slicer activity of ARGONAUTE1 Is required specifically for the phasing, not production, of trans-acting short interfering RNAs in Arabidopsis. Plant Cell 28(7):1563–1580. doi: 10.1105/tpc1600121Brodersen P, Sakvarelidze-Achard L, Bruun-Rasmussen M, Dunoyer P, Yamamoto YY, Sieburth L, Voinnet O (2008) Widespread translational inhibition by plant miRNAs and siRNAs. Science 320(5880):1185–1190. doi: 10.1126/science1159151Li S, Le B, Ma X, Li S, You C, Yu Y, Zhang B, Liu L, Gao L, Shi T, Zhao Y, Mo B, Cao X, Chen X (2016) Biogenesis of phased siRNAs on membrane-bound polysomes in Arabidopsis. Elife 5:e22750. doi: 10.7554/eLife22750Zeng Y, Yi R, Cullen BR (2003) MicroRNAs and small interfering RNAs can inhibit mRNA expression by similar mechanisms. Proc Natl Acad Sci U S A 100(17):9779–9784. doi: 10.1073/pnas1630797100Iwakawa HO, Tomari Y (2013) Molecular insights into microRNA-mediated translational repression in plants. Mol Cell 52(4):591–601. doi: 10.1016/jmolcel201310033Li S, Liu L, Zhuang X, Yu Y, Liu X, Cui X, Ji L, Pan Z, Cao X, Mo B, Zhang F, Raikhel N, Jiang L, Chen X (2013) MicroRNAs inhibit the translation of target mRNAs on the endoplasmic reticulum in Arabidopsis. Cell 153(3):562–574. doi: 10.1016/jcell201304005Li JF, Chung HS, Niu Y, Bush J, McCormack M, Sheen J (2013) Comprehensive protein-based artificial microRNA screens for effective gene silencing in plants. Plant Cell 25(5):1507–1522. doi: 10.1105/tpc113112235Liu MJ, SH W, JF W, Lin WD, YC W, Tsai TY, Tsai HL, SH W (2013) Translational landscape of photomorphogenic Arabidopsis. Plant Cell 25(10):3699–3710. doi: 10.1105/tpc113114769Aukerman MJ, Sakai H (2003) Regulation of flowering time and floral organ identity by a microRNA and its APETALA2-like target genes. Plant Cell 15(11):2730–2741. doi: 10.1105/tpc016238Chen X (2004) A microRNA as a translational repressor of APETALA2 in Arabidopsis flower development. Science 303(5666):2022–2025. doi: 10.1126/science1088060Gandikota M, Birkenbihl RP, Hohmann S, Cardon GH, Saedler H, Huijser P (2007) The miRNA156/157 recognition element in the 3′ UTR of the Arabidopsis SBP box gene SPL3 prevents early flowering by translational inhibition in seedlings. Plant J 49(4):683–693. doi: 10.1111/j1365-313X200602983xYang L, Wu G, Poethig RS (2012) Mutations in the GW-repeat protein SUO reveal a developmental function for microRNA-mediated translational repression in Arabidopsis. Proc Natl Acad Sci U S A 109(1):315–320. doi: 10.1073/pnas1114673109Mallory AC, Hinze A, Tucker MR, Bouche N, Gasciolli V, Elmayan T, Lauressergues D, Jauvion V, Vaucheret H, Laux T (2009) Redundant and specific roles of the ARGONAUTE proteins AGO1 and ZLL in development and small RNA-directed gene silencing. PLoS Genet 5(9):e1000646. doi: 10.1371/journalpgen1000646Hou CY, Lee WC, Chou HC, Chen AP, Chou SJ, Chen HM (2016) Global analysis of truncated RNA ends reveals new insights into ribosome stalling in plants. Plant Cell 28(10):2398–2416. doi: 10.1105/tpc1600295Rogers K, Chen X (2013) Biogenesis, turnover, and mode of action of plant microRNAs. Plant Cell 25(7):2383–2399. doi: 10.1105/tpc113113159Behm-Ansmant I, Rehwinkel J, Doerks T, Stark A, Bork P, Izaurralde E (2006) mRNA degradation by miRNAs and GW182 requires both CCR4:NOT deadenylase and DCP1:DCP2 decapping complexes. Genes Dev 20(14):1885–1898. doi: 10.1101/gad1424106Wu L, Fan J, Belasco JG (2006) MicroRNAs direct rapid deadenylation of mRNA. Proc Natl Acad Sci U S A 103(11):4034–4039. doi: 10.1073/pnas0510928103Schirle NT, MacRae IJ (2012) The crystal structure of human Argonaute2. Science 336(6084):1037–1040. doi: 10.1126/science1221551Pfaff J, Hennig J, Herzog F, Aebersold R, Sattler M, Niessing D, Meister G (2013) Structural features of Argonaute-GW182 protein interactions. Proc Natl Acad Sci U S A 110(40):E3770–E3779. doi: 10.1073/pnas1308510110Ma X, Kim EJ, Kook I, Ma F, Voshall A, Moriyama E, Cerutti H (2013) Small interfering RNA-mediated translation repression alters ribosome sensitivity to inhibition by cycloheximide in Chlamydomonas reinhardtii. Plant Cell 25(3):985–998. doi: 10.1105/tpc113109256Law JA, Jacobsen SE (2010) Establishing, maintaining and modifying DNA methylation patterns in plants and animals. Nat Rev Genet 11(3):204–220. doi: 10.1038/nrg2719Xie Z, Johansen LK, Gustafson AM, Kasschau KD, Lellis AD, Zilberman D, Jacobsen SE, Carrington JC (2004) Genetic and functional diversification of small RNA pathways in plants. PLoS Biol 2(5):E104. doi: 10.1371/journalpbio0020104Herr AJ, Jensen MB, Dalmay T, Baulcombe DC (2005) RNA polymerase IV directs silencing of endogenous DNA. Science 308(5718):118–120. doi: 10.1126/science1106910Kanno T, Huettel B, Mette MF, Aufsatz W, Jaligot E, Daxinger L, Kreil DP, Matzke M, Matzke AJ (2005) Atypical RNA polymerase subunits required for RNA-directed DNA methylation. Nat Genet 37(7):761–765. doi: 10.1038/ng1580Onodera Y, Haag JR, Ream T, Costa Nunes P, Pontes O, Pikaard CS (2005) Plant nuclear RNA polymerase IV mediates siRNA and DNA methylation-dependent heterochromatin formation. Cell 120(5):613–622. doi: 10.1016/jcell200502007Haag JR, Ream TS, Marasco M, Nicora CD, Norbeck AD, Pasa-Tolic L, Pikaard CS (2012) In vitro transcription activities of Pol IV, Pol V, and RDR2 reveal coupling of Pol IV and RDR2 for dsRNA synthesis in plant RNA silencing. Mol Cell 48(5):811–818. doi: 10.1016/jmolcel201209027Pontes O, Li CF, Costa Nunes P, Haag J, Ream T, Vitins A, Jacobsen SE, Pikaard CS (2006) The Arabidopsis chromatin-modifying nuclear siRNA pathway involves a nucleolar RNA processing center. Cell 126(1):79–92. doi: 10.1016/jcell200605031Li CF, Pontes O, El-Shami M, Henderson IR, Bernatavichute YV, Chan SW, Lagrange T, Pikaard CS, Jacobsen SE (2006) An ARGONAUTE4-containing nuclear processing center colocalized with Cajal bodies in Arabidopsis thaliana. Cell 126(1):93–106. doi: 10.1016/jcell200605032El-Shami M, Pontier D, Lahmy S, Braun L, Picart C, Vega D, Hakimi MA, Jacobsen SE, Cooke R, Lagrange T (2007) Reiterated WG/GW motifs form functionally and evolutionarily conserved ARGONAUTE-binding platforms in RNAi-related components. Genes Dev 21(20):2539–2544. doi: 10.1101/gad451207Li CF, Henderson IR, Song L, Fedoroff N, Lagrange T, Jacobsen SE (2008) Dynamic regulation of ARGONAUTE4 within multiple nuclear bodies in Arabidopsis thaliana. PLoS Genet 4(2):e27. doi: 10.1371/journalpgen0040027Bies-Etheve N, Pontier D, Lahmy S, Picart C, Vega D, Cooke R, Lagrange T (2009) RNA-directed DNA methylation requires an AGO4-interacting member of the SPT5 elongation factor family. EMBO Rep 10(6):649–654. doi: 10.1038/embor200931He XJ, Hsu YF, Zhu S, Wierzbicki AT, Pontes O, Pikaard CS, Liu HL, Wang CS, Jin H, Zhu JK (2009) An effector of RNA-directed DNA methylation in Arabidopsis is an ARGONAUTE 4- and RNA-binding protein. Cell 137(3):498–508. doi: 10.1016/jcell200904028Zhong X, Du J, Hale CJ, Gallego-Bartolome J, Feng S, Vashisht AA, Chory J, Wohlschlegel JA, Patel DJ, Jacobsen SE (2014) Molecular mechanism of action of plant DRM de novo DNA methyltransferases. Cell 157(5):1050–1060. doi: 10.1016/jcell201403056Cao X, Jacobsen SE (2002) Locus-specific control of asymmetric and CpNpG methylation by the DRM and CMT3 methyltransferase genes. Proc Natl Acad Sci U S A 99(Suppl 4):16491–16498. doi: 10.1073/pnas162371599Lahmy S, Pontier D, Bies-Etheve N, Laudie M, Feng S, Jobet E, Hale CJ, Cooke R, Hakimi MA, Angelov D, Jacobsen SE, Lagrange T (2016) Evidence for ARGONAUTE4-DNA interactions in RNA-directed DNA methylation in plants. Genes Dev 30(23):2565–2570. doi: 10.1101/gad289553116Zheng X, Zhu J, Kapoor A, Zhu JK (2007) Role of Arabidopsis AGO6 in siRNA accumulation, DNA methylation and transcriptional gene silencing. EMBO J 26(6):1691–1701. doi: 10.1038/sjemboj7601603Havecker ER, Wallbridge LM, Hardcastle TJ, Bush MS, Kelly KA, Dunn RM, Schwach F, Doonan JH, Baulcombe DC (2010) The Arabidopsis RNA-directed DNA methylation Argonautes functionally diverge based on their expression and interaction with target loci. Plant Cell 22(2):321–334. doi: 10.1105/tpc109072199Eun C, Lorkovic ZJ, Naumann U, Long Q, Havecker ER, Simon SA, Meyers BC, Matzke AJ, Matzke M (2011) AGO6 functions in RNA-mediated transcriptional gene silencing in shoot and root meristems in Arabidopsis thaliana. PLoS One 6(10):e25730. doi: 10.1371/journalpone0025730Duan CG, Zhang H, Tang K, Zhu X, Qian W, Hou YJ, Wang B, Lang Z, Zhao Y, Wang X, Wang P, Zhou J, Liang G, Liu N, Wang C, Zhu JK (2015) Specific but interdependent functions for Arabidopsis AGO4 and AGO6 in RNA-directed DNA methylation. EMBO J 34(5):581–592. doi: 10.15252/embj201489453McCue AD, Panda K, Nuthikattu S, Choudury SG, Thomas EN, Slotkin RK (2015) ARGONAUTE 6 bridges transposable element mRNA-derived siRNAs to the establishment of DNA methylation. EMBO J 34(1):20–35. doi: 10.15252/embj201489499Zhang Z, Liu X, Guo X, Wang XJ, Zhang X (2016) Arabidopsis AGO3 predominantly recruits 24-nt small RNAs to regulate epigenetic silencing. Nat Plants 2(5):16049. doi: 10.1038/nplants201649Wu J, Yang Z, Wang Y, Zheng L, Ye R, Ji Y, Zhao S, Ji S, Liu R, Xu L, Zheng H, Zhou Y, Zhang X, Cao X, Xie L, Wu Z, Qi Y, Li Y (2015) Viral-inducible Argonaute18 confers broad-spectrum virus resistance in rice by sequestering a host microRNA. Elife 4:05733. doi: 10.7554/eLife05733Wu J, Yang R, Yang Z, Yao S, Zhao S, Wang Y, Li P, Song X, Jin L, Zhou T, Lan Y, Xie L, Zhou X, Chu C, Qi Y, Cao X, Li Y (2017) ROS accumulation and antiviral defence control by microRNA528 in rice. Nat Plants 3:16203. doi: 10.1038/nplants2016203Wei W, Ba Z, Gao M, Wu Y, Ma Y, Amiard S, White CI, Rendtlew Danielsen JM, Yang YG, Qi Y (2012) A role for small RNAs in DNA double-strand break repair. Cell 149(1):101–112. doi: 10.1016/jcell201203002Oliver C, Santos JL, Pradillo M (2014) On the role of some ARGONAUTE proteins in meiosis and DNA repair in Arabidopsis thaliana. Front Plant Sci 5:177. doi: 10.3389/fpls201400177Ye R, Chen Z, Lian B, Rowley MJ, Xia N, Chai J, Li Y, He XJ, Wierzbicki AT, Qi Y (2016) A Dicer-independent route for biogenesis of siRNAs that direct DNA methylation in Arabidopsis. Mol Cell 61(2):222–235. doi: 10.1016/jmolcel201511015Dolata J, Bajczyk M, Bielewicz D, Niedojadlo K, Niedojadlo J, Pietrykowska H, Walczak W, Szweykowska-Kulinska Z, Jarmolowski A (2016) Salt stress reveals a new role for ARGONAUTE1 in miRNA biogenesis at the transcriptional and posttranscriptional levels. Plant Physiol 172(1):297–312. doi: 10.1104/pp1600830Singh RK, Gase K, Baldwin IT, Pandey SP (2015) Molecular evolution and diversification of the Argonaute family of proteins in plants. BMC Plant Biol 15(1):23. doi: 10.1186/s12870-014-0364-6Singh RK, Pandey SP (2015) Evolution of structural and functional diversification among plant Argonautes. Plant Signal Behav 10(10):e1069455. doi: 10.1080/1559232420151069455Bohmert K, Camus I, Bellini C, Bouchez D, Caboche M, Benning C (1998) AGO1 defines a novel locus of Arabidopsis controlling leaf development. EMBO J 17(1):170–180. doi: 10.1093/emboj/171170Kidner CA, Martienssen RA (2004) Spatially restricted microRNA directs leaf polarity through ARGONAUTE1. Nature 428(6978):81–84. doi: 10.1038/nature02366Sorin C, Bussell JD, Camus I, Ljung K, Kowalczyk M, Geiss G, McKhann H, Garcion C, Vaucheret H, Sandberg G, Bellini C (2005) Auxin and light control of adventitious rooting in Arabidopsis require ARGONAUTE1. Plant Cell 17(5):1343–1359. doi: 10.1105/tpc105031625Yang L, Huang W, Wang H, Cai R, Xu Y, Huang H (2006) Characterizations of a hypomorphic argonaute1 mutant reveal novel AGO1 functions in Arabidopsis lateral organ development. Plant Mol Biol 61(1-2):63–78. doi: 10.1007/s11103-005-5992-7Kidner CA, Martienssen RA (2005) The developmental role of microRNA in plants. Curr Opin Plant Biol 8(1):38–44. doi: 10.1016/jpbi200411008Wu L, Zhang Q, Zhou H, Ni F, Wu X, Qi Y (2009) Rice microRNA effector complexes and targets. Plant Cell 21(11):3421–3435. doi: 10.1105/tpc109070938Vaucheret H (2008) Plant ARGONAUTES. Trends Plant Sci 13(7):350–358. doi: 10.1016/jtplants200804007Hunter C, Sun H, Poethig RS (2003) The Arabidopsis heterochronic gene ZIPPY is an ARGONAUTE family member. Curr Biol 13(19):1734–1739Adenot X, Elmayan T, Lauressergues D, Boutet S, Bouche N, Gasciolli V, Vaucheret H (2006) DRB4-dependent TAS3 trans-acting siRNAs control leaf morphology through AGO7. Curr Biol 16(9):927–932. doi: 10.1016/jcub200603035Fahlgren N, Montgomery TA, Howell MD, Allen E, Dvorak SK, Alexander AL, Carrington JC (2006) Regulation of AUXIN RESPONSE FACTOR3 by TAS3 ta-siRNA affects developmental timing and patterning in Arabidopsis. Curr Biol 16(9):939–944. doi: 10.1016/jcub200603065Axtell MJ, Jan C, Rajagopalan R, Bartel DP (2006) A two-hit trigger for siRNA biogenesis in plants. Cell 127(3):565–577. doi: 10.1016/jcell200609032Hunter C, Willmann MR, Wu G, Yoshikawa M, de la Luz G-NM, Poethig SR (2006) Trans-acting siRNA-mediated repre