Roles of Organellar RNA-Binding Proteins in Plant Growth, Development, and Abiotic Stress Responses.

Kwanuk Lee,Hunseung Kang

doi:10.3390/ijms21124548

Abstract

Organellar gene expression (OGE) in chloroplasts and mitochondria is primarily modulated at post-transcriptional levels, including RNA processing, intron splicing, RNA stability, editing, and translational control. Nucleus-encoded Chloroplast or Mitochondrial RNA-Binding Proteins (nCMRBPs) are key regulatory factors that are crucial for the fine-tuned regulation of post-transcriptional RNA metabolism in organelles. Although the functional roles of nCMRBPs have been studied in plants, their cellular and physiological functions remain largely unknown. Nevertheless, existing studies that have characterized the functions of nCMRBP families, such as chloroplast ribosome maturation and splicing domain (CRM) proteins, pentatricopeptide repeat (PPR) proteins, DEAD-Box RNA helicase (DBRH) proteins, and S1-domain containing proteins (SDPs), have begun to shed light on the role of nCMRBPs in plant growth, development, and stress responses. Here, we review the latest research developments regarding the functional roles of organellar RBPs in RNA metabolism during growth, development, and abiotic stress responses in plants.

Highlights

Plant chloroplasts and mitochondria are thought to be derived from free-living cyanobacteria and α-proteobacteria, respectively [1,2]
These results clearly indicate that Nucleus-encoded Chloroplast or Mitochondrial RNA-Binding Proteins (nCMRBPs), which carry out RNA chaperone activities, have significant roles in the regulation of organellar RNA metabolism during plant growth, development, and responses to abiotic stress
The functional roles of nucleus-encoded organellar RBPs are still not fully understood, the latest studies of the cellular and physiological functions of nCMRBPs has shed some light on the significance of nCMRBPs for organellar RNA metabolism during plant growth, development, and environmental stress responses

Summary

Introduction

Plant chloroplasts and mitochondria are thought to be derived from free-living cyanobacteria and α-proteobacteria, respectively [1,2]. The OGE mechanisms in plant organelles are much more complex than those of their bacterial ancestors [5,6] and require thousands of nucleus-encoded proteins for maintaining OGE machinery and organellar function. This indicates the importance of interactions between the organelles and nucleus in controlling fine-tuned OGE through a nucleus-to-organelle anterograde or an organelle-to nucleus retrograde signaling [7,8,9]. The regulation of post-transcriptional RNA processing in organelles requires hundreds of nucleus-encoded chloroplast or mitochondrial RNA-binding proteins (nCMRBPs) during acclimation to environmental stress, as well as during plant growth and. RReecceennttstsutduideisehs ahvaevuenuconvceorveedrethdatthnaCtMnRCBMPRs BplPasy palcaryitiacaclrriotilceailnrpollaentingrpolwantht ganrodwstthresasnrdessptorensssesr[e1s5p–o1n9s]e. sM[o1r5e–o1v9e].r, Manoarleyosviseor,f athnealcyhsaisraoctfertihseticcshoafrancCteMriRstBicPshoafs dnCemMoRnBstPrahteads dtheamt othnesytraptoesdsetshsatmtuheltyippleoscsoensssemrvueldtipmleotciofsnasenrdveddommaoitnifss, wanhdicdhoimncaliunds,ewchhliocrhoipnlcalsutdReNcAhlosrpolipcliansgt RanNdAribspolsiocimnge manadturriabtoiosnom(CeRmMa)t,upreantitoantri(cCoRpeMp)t,idpeernetpateraict o(PpPepRt)i,dDeErAepDe-abto(xPRPNR)A, DheElAicDas-ebo(Dx BRRNHA), haneldicSa1seR(NDAB-RbHin)d, ianngddSo1mRaNinA(S-bDinPd) i[n1g9–d2o2m]. aIminp(oSrDtaPn)t[ly1,9i–t2i2s]n. oImwpkonrotawnntlyth, aitt itshenonwCMknRoBwPsnftuhnactttiohne nasCeMitRhBerPsspfeucnicfitcioRnNaAs -ebitihnedrinsgpepcriofitceiRnNs Aor-bnionnd-isnpgecpirfiocteRinNsAo-rbninodni-nsgpepcriofitceiRnNs A(R-NbiAndcinhgapperrootneeins)s, w(RhNicAh cfhacaiplietraotensest)h,ewchoircrhecftacfoillidtaintegs othf ethceortraercgteftoRldNinAg sotfrutchteurteardgeutriRnNg Aplasntrtugctruorwetdhuarnindgupnldanert genrovwirtohnmanedntuanl dsetrreesns v[1ir5o,2n3m].enCthallosrtorepslsas[t1-5o,2r3m]. iCtohclohroonpdlarisat--loocramliziteodchCoRnMdr,iaP-PloRc,alDizBeRdHC,RaMnd, PSPDRP, DprBoRteHin, sanhdavSeDbPeepnroatsesinessshedavienbteeernmassosfestsheedirinrotleersmass oRfNthAeicrhraopleesroanseRsN[2A1,c2h4–a2p7e]r.onInesth[2is1,2re4v–i2e7w]., wInetwhiisll rfeovcuieswo,nwtheewreicllenfot caudsvaonncetsheinrreecseenatrcahdovnantchees fuinncrteiosenaarcnhd ocenlluthlaerfmuneccthioannisamnds ocfeClluRlMar, mPPeRch, DanBiRsmHs, aonfdCSRDMP,pPrPotRe,inDsBinRHor,gaanndellSaDr RPNpAromteeintasbionliosmrgadnuerlilnagr pRlNanAt gmroewtatbho, ldisemveldouprminegntp, laanndt gabroiowtitchs, tdreesvselroepspmoennste,sa. nd abiotic stress responses

CCRRMM PPrroteins

SDP Proteins

Functions of nCMRBPs in Plant Growth and Development

Physiological Functions of nCMRBPs in Abiotic Stress Responses

Cellular Roles of nCMRBPs in Organellar RNA Metabolism

Conclusions and Future Directions