Peptide hormones play pivotal roles in many physiological processes through coordinating developmental and environmental cues among different cells. Peptide hormones are recognized by their receptors that convey signals to downstream targets and interact with multiple pathways to fine-tune plant growth. Extensive research has illustrated the mechanisms of peptides in shoots but functional studies of peptides in roots are scarce. Reactive oxygen species (ROS) are known to be involved in stress-related events. However, recent studies have shown that they are also associated with many processes that regulate plant development. Here, we focus on recent advances in understanding the relationships between peptide hormones and their receptors during root growth including outlines of how ROS are integrated with these networks.

The Root meristem growth factor 1 (RGF1) peptide extends the PLETHORA2 (PLT2) protein gradient by altering the distinct localization of superoxide (O2−) and hydrogen peroxide (H2O2) among the root developmental zones. However, the underlying mechanism through which reactive oxygen species (ROS) regulate PLT2 stability is unclear. Here, we demonstrate that the 212th cysteine of PLT2 is pivotal in modulating PLT2 stability through ROS. The PLT2 protein concentration gradient rapidly decreases in the elongation zone, where H2O2 accumulation initiates. However, substituting the 212th cysteine of PLT2 with serine (PLT2C212S) results in PLT2 being more stable in the elongation zone, more broadly localized by RGF1, and showing robust resistance to H2O2. The sulfenylation of PLT2 was detected following treatment with H2O2 at high concentrations, suggesting that S-sulfenylation of the 212th cysteine controls PLT2 protein stability through local ROS distributions. These findings show that the formation of the PLT2 concentration gradient through ROS depends on a PLT2 sulfenylation mechanism that involves the 212th cysteine.

(1) Background: Root hairs are specialized structures involved in water and plant nutrient uptake. They elongate from epidermal cells following a complex developmental program. ß-cyanoalanine synthase (CAS), which is mainly involved in hydrogen cyanide (HCN) detoxification in Arabidopsis thaliana, plays a role in root hair elongation, as evidenced by the fact that cas-c1 mutants show a severe defect in root hair shape. In addition to root hairs, CAS C1 is expressed in the quiescent center and meristem. (2) Methods: To identify its role in root hair formation, we conducted single-cell proteomics analysis by isolating root hair cells using Fluorescence-activated Cell Sorting (FACS) from wild-type and cas-c1 mutants. We also analyzed the presence of S-cyanylation, a protein post-translational modification (PTM) mediated by HCN and affecting cysteine residues and protein activity in proteins of wild type and cas-c1 mutants. (3) Results and Conclusions: We have found that the cas-c1 mutation has no visible effect on quiescent center or meristem root tissue, in both control and nutrient-deprivation conditions. We have identified more than 3900 proteins in root hairs and we have found that several proteins involved in root hair development, related to the receptor kinase FERONIA signaling and DNA methylation, are modified by S-cyanylation.

In martial arts training, it is important to have a training partner; however, this can be difficult due to scheduling problems. This paper proposes information visualization during sparring training in virtual environments. By reproducing offensive moves in the virtual environment, the person practicing understands them stereoscopically and can practice repeatedly without requiring an actual sparring partner. In addition, to improve movement, information about offensive and defensive postures is displayed.

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 212 ^th cysteine of the PLT2 protein plays a pivotal role in modulating PLT2 stability through the ROS altered by RGF1. The substitution of the 212 ^th cysteine of PLT2 with serine (PLT2 ^C212S ) enhanced the PLT2 protein stability upon RGF1 and resulted in robust resistance to ROS relative to the native PLT2. Accordingly, PLT2 ^C212S 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 212 ^th cysteine of PLT2.

Summary: Roots adapt to growth‐restricting but nonlethal high temperatures. Although lethal heat shock and moderately elevated temperatures have been extensively studied, the effects of nonlethal thermal stress on root development remain unclear. We defined 31°C as a nonlethal thermal stress condition in Arabidopsis thaliana and examined its effects using phenotypic and transcriptomic analyses. Compared with 22°C, growth at 31°C reduced primary root growth, meristem size, and superoxide ( O ₂ ˙ ⁻ ) accumulation, accompanied by altered redox states, restricted distribution of the meristem regulator PLETHORA2 ( PLT2 ), and accelerated differentiation. Transcriptome analyses showed repression of meristem‐associated genes and induction of differentiation‐related genes rather than activation of canonical heat‐shock genes. Mutants defective in the RGF ‐ RGFR ‐ PLT2 pathway were hypersensitive to nonlethal thermal stress. By contrast, exogenous RGF treatment restored primary root meristem defects and promoted lateral root elongation under prolonged stress. These findings indicate that the RGF‐RGFR‐PLT2 pathway plays a central role in root adaptation to nonlethal thermal stress and suggest that manipulation of RGF signaling could improve root thermotolerance and crop resilience under elevated temperatures.