Transcriptional landscapes of de novo root regeneration from detached Arabidopsis leaves revealed by time-lapse and single-cell RNA sequencing analyses

Detached Arabidopsis thaliana leaves can regenerate adventitious roots,providing a platformfor studying de novo root regeneration(DNRR).However,the comprehensive transcriptional framework of DNRR remains elusive.Here,we provide a high-resolution landscape of transcriptome reprogramming from wound response to root organogenesis in DNRR and show key factors involved in DNRR.Time-lapse RNA sequencing(RNA-seq)of the entire leaf within 12 h of leaf detachment revealed rapid activation of jasmonate,ethylene,and reactive oxygen species(ROS)pathways in response towounding.Genetic analyses confirmed that ethylene andROSmay serve as wound signals to promoteDNRR.Next,time-lapse RNA-seq within 5 d of leaf detachment revealed the activation of genes involved in organogenesis,wound-induced regeneration,and resource allocation in the wounded region of detached leaves during adventitious rooting.Genetic studies showed that BLADE-ON-PETIOLE1/2,which control aboveground organs,PLETHORA3/5/7,which control root organogenesis,and ETHYLENE RESPONSE FACTOR115,which controlswound-induced regeneration,are involved in DNRR.Furthermore,single-cell RNA-seq data revealed gene expression patterns in thewounded region of detached leaves during adventitious rooting.Overall,our study not only provides transcriptome tools but also reveals key factors involved in DNRR from detached Arabidopsis leaves.

MiR172介导的AP2-like转录因子表达对大岩桐花期调控的研究（英文）

目的:本文通过研究microRNA172a(miR172a)对成花途径中关键靶基因APETALA2类(AP2-like)的调控作用及其机理分析,探索通过操纵miRNA表达改变观赏植物花期的基因工程分子育种新策略。创新点:本研究基于植物miR172序列和功能的高度保守性,通过转基因的方法操纵大岩桐miR172的表达,进而影响AP2-like基因的表达,并起到调控花期的作用。方法:本研究借用拟南芥miR172a的已知序列构建组成型过表达载体35S:miR172a和抑制miR172表达的35S:MIM172载体。利用农杆菌介导法成功获得了35S:miR172a过表达株系以及抑制miR172作用的35S:MIM172株系,并利用cDNA末端快速扩增技术(rapid amplification of cDNA ends,RACE)克隆得到了大岩桐AP2-likecDNA全序列,并通过实时荧光定量聚合酶链式反应技术(qPCR)检测转基因株系中AP2-like的表达变化。结论:短日照条件下,35S:miR172a过表达株系花期比野生型提前(47.00±2.16)天;35S:MIM172株系花期延迟(7.00±4.28)天。在35S:miR172a过表达株系中miR172的表达水平明显上升,其靶基因SsAP2-like的表达量明显下降;35S:MIM172株系中miR172的积累水平受到抑制,而SsAP2-like的表达量明显上升,表明miR172介导调控SsAP2的表达对大岩桐成花转变具有促进作用。通过改变miR172的表达调控关键靶基因进而改变花期的方法可以作为调节观赏植物开花时间的有效策略。

The heterochronic gene Oryza sativa LIKE HETEROCHROMATIN PROTEIN 1 modulates miR156b/c/i/e levels

The juvenile-to-adult transition in plants involves changes in vegetative growth and plant architecture;the timing of this transition has important implications for agriculture.The microRNA miR156 regulates this transition and shoot maturation in plants.In Arabidopsis thaliana,deposition of histone H3 trimethylation on lysine 27(H3K27me3,a repressive mark)at the MIR156A/C loci is regulated by Polycomb Repressive Complex 1(PRC1)or PRC2,depending on the developmental stage.The levels of miR156 progressively decline during shoot maturation.The amount of H3K27me3 at MIR156A/C loci affects miR156 levels;however,whether this epigenetic regulation is conserved remains unclear.Here,we found that in rice(Oryza sativa),the putative PRC1 subunit LIKE HETEROCHROMATIN PROTEIN 1(OsLHP1),with the miR156–SQUAMOSA PROMOTER BINDING PROTEIN-LIKE(SPL)module,affects developmental phase transitions.Loss of OsLHP1 function results in ectopic expression of MIR156B/C/I/E,phenocopy of miR156 overexpression,and reduced H3k27me3 levels at MIR156B/C/I/E.This indicates that OsLHP1 has functionally diverged from Arabidopsis LHP1.Genetic and transcriptome analyses of wild-type,miR156b/c-overexpression,and Oslhp1-2 mutant plants suggest that OsLHP1 acts upstream of miR156 and SPL during the juvenile-to-adult transition.Therefore,modifying the OsLHP1–miR156–SPL pathway may enable alteration of the vegetative period and plant architecture.