The specification and commitment of lateral root founder cells (LRFCs) from postembryonic pericycle cells are critical steps in LR development, yet their earliest molecular determinants remain unclear. Using single-cell transcriptomics, we resolved transcriptional transitions guiding LRFC fate in Arabidopsis thaliana and identified five distinct phases of transcriptional progression during LRFC specification. Through differentially expressed gene analysis and phenotypic observation, we showed that application of exogenous GA (20 and 50 μM) promoted the nuclear migration and division in LRFCs independently of DELLA signaling, and revealed that Gibberellic acid-stimulated Arabidopsis 1 (GASA1) functions as a key mediator of gibberellin (GA) to accelerate the LRFC progression. Further histochemical staining and cytological observations demonstrated that GASA1 mediated the GA-triggered reactive oxygen species (ROS) accumulation to reinforce the LRFC commitment. The GA-GASA1-ROS module is evolutionarily conserved, with GA-ROS-driven LRFC commitment being fundamental across angiosperms. Notably, GASA1 emerged with root evolution in early land plants and diversified alongside lateral and shoot-borne root systems, revealing a conserved GA-ROS axis in plant organogenesis.
Xin-Qiao Du, Rahul Shaw, Jun Zhang et al.· Plant Communications· 0 citations
Higher grain weight and stronger seed dormancy are key objectives for improving rice (Oryza sativa) yield and inhibiting pre-harvest sprouting. Therefore, identifying genes that coordinately regulate grain weight and seed dormancy is an urgent priority. Here, we report that knocking out miR1866 (KO1866) increased grain weight and reinforced dormancy. We identified the transcript of ubiquitin-specific processing protease 7 (OsUBP7), which encodes a protein with deubiquitination activity in vitro, as the primary target of miR1866. Consistent with miRNA-directed repression, OsUBP7 transcript abundance generally showed a spatiotemporal pattern opposite to miR1866 accumulation during rice development. Overexpression of native OsUBP7 (UBP7-OE) or a miR1866-resistant form (mUBP7-OE) phenocopied KO1866 by producing heavier grains with stronger dormancy. The miR1866-OsUBP7 module also altered the expression of genes associated with sucrose and starch metabolism, cell-cycle control, grain development, and abscisic acid (ABA) biosynthesis and signaling. Accordingly, KO1866, UBP7-OE, and mUBP7-OE plants contained more ABA and responded more sensitively to exogenous ABA than wild type. OsUBP7 interacted with OsDA1 (encoded by Os06g0182500) and UBIQUITIN-CONJUGATING ENZYME (OsUCE1; encoded by Os02g0833300), thereby affecting hull cell division and ABA signaling and ultimately regulating grain weight and seed dormancy, respectively. Our results indicate that the miR1866-OsUBP7 module regulates grain weight and seed dormancy in rice, highlighting its potential for engineering crops with improved yields and stronger seed dormancy.
Ya-Fan Zhao, Yuan Li, Zongrun Li et al.· Journal of Integrative Plant...· 0 citations
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