Biology subjects

Lai, J.-K.

Publications and source records attributed to Lai, J.-K..

3 recordsLinked to original sources

bioRxiv2026

Conserved RGF1 peptide signaling regulates root meristem development through ROS in Arabidopsis and rice

The root meristem is essential for stem cell maintenance and root development in plants. In Arabidopsis, Root meristem Growth Factor (RGF) peptides and their receptors regulate root meristem size through reactive oxygen species (ROS)-dependent signalling. RGF1-mediated ROS redistribution post-translationally stabilises the root meristem master regulator PLETHORA2 (PLT2). Although genomic studies suggest that RGF-receptor modules are evolutionarily conserved across land plants, their functional characterisation has remained largely limited to Arabidopsis. Here, we show that Oryza sativa RGF1-1 (OsRGF1-1) functions as a rice homologue of Arabidopsis RGF1 (AtRGF1). CRISPR/Cas9-generated Osrgf1-1 mutants exhibited shorter seminal roots, reduced root meristem size, and decreased superoxide (O2*-) accumulation. EdU staining further confirmed that cell proliferation activity was reduced in the Osrgf1-1 mutants. The Osrgf1-1 mutants were sensitive to low concentrations of chemically synthesised mature OsRGF1-1 peptide. This low dose of OsRGF1-1 peptide restored seminal root growth and O2*- accumulation in the Osrgf1-1 mutants but had no detectable effect on the wild type. Functional analyses using Arabidopsis rgfr receptor mutants further demonstrated that OsRGF1-1 is perceived through conserved RGF receptor machinery. Together, our findings provide the first functional evidence that the RGF1-receptor-ROS signalling module is evolutionarily conserved between dicots and monocots in the regulation of root meristem development.

plant biology↗

bioRxiv2025

Root meristem growth factor (RGF) peptide signaling as a molecular bridge between root development and non-lethal thermal stress adaptation

O_LIRoots adapt to temperature ranges that restrict growth but are not lethal. Although lethal heat shock and moderately high temperatures have been studied in detail, the effects of non-lethal high temperatures on root development remain largely unknown. We defined 31{degrees}C as a non-lethal thermal stress in Arabidopsis thaliana and examined its impact on root growth using phenotypic analyses and developmental-zone-specific transcriptomics. C_LIO_LICompared to growth at 22{degrees}C, at 31{degrees}C, primary root growth, meristem size, and superoxide (O2-) accumulation were reduced, and the distribution of the meristem master regulator PLETHORA2 (PLT2) became restricted. Transcriptome analysis revealed a strong downregulation of RGFs, RGFRs, and PLT2, rather than activation of heat shock-inducible genes. C_LIO_LIThese gene mutants were more sensitive to non-lethal thermal stress. In contrast, RGF treatment recovered heat-stress-induced defects. Beyond alleviating the stress in the primary root meristem, RGF treatments promoted lateral root elongation under prolonged non-lethal thermal stress, resulting in a more complex root system. C_LIO_LIThese results indicate that the RGF-RGF receptor-PLT2 pathway plays a central role in root adaptation to non-lethal heat stress rather than the canonical heat shock response pathway and suggest that manipulating RGF signaling could enhance root thermotolerance and crop resilience under elevated temperatures. C_LI

plant biology↗

bioRxiv2024

RGF1 controls PLT2 protein stability through ROS-dependent regulation of a cysteine residue in root meristem development

The protein concentration gradients of the master regulators of the root meristem, named the PLETHORA proteins, modulate the root meristem size. Root meristem growth factor 1 (RGF1) peptide extends the PLETHORA2 (PLT2) protein gradients by altering reactive oxygen species (ROS) distributions. However, the underlying mechanism through which the ROS alterations regulate PLT2 remains unknown. Here, we demonstrate that the 212th cysteine of the PLT2 protein plays a pivotal role in modulating PLT2 stability through the ROS altered by RGF1. The substitution of the 212th cysteine of PLT2 with serine (PLT2C212S) enhanced the PLT2 protein stability upon RGF1 and resulted in robust resistance to ROS relative to the native PLT2. Accordingly, PLT2C212S modulated expressions of certain specific root development-related genes to a greater extent than native PLT2. In summary, these findings show that the PLT2 concentration gradient formation through ROS, modulated by RGF1, is dependent on a mechanism involving the 212th cysteine of PLT2.

plant biology↗