The Plant Journal最新文献

Post-harvest loss of fruits and vegetables poses significant challenges to food security and economic sustainability, primarily due to ripening-associated excessive softening that shortens shelf life and increases susceptibility to pathogens. N-glycans, N-glycoproteins, and their processing enzymes are integral to various plant processes, including fruit ripening. Among these, α-D-mannosidase (α-Man) and β-D-N-acetylhexosaminidase (β-Hex) are key ripening-specific enzymes that modulate fruit softening. Previously, we have shown that RNAi-mediated suppression of α-Man or β-Hex improves fruit shelf life and firmness in both climacteric and non-climacteric fruits. However, the underlying molecular and biochemical basis of fruit softening regulation by α-Man and β-Hex was not well understood. In this study, we developed transgenic tomato (Solanum lycopersicum) plants by silencing α-Man and β-Hex simultaneously using RNAi. Suppression of these enzymes reduces N-glycoprotein degradation, downregulates pectin dissolution, and inhibits ripening-related gene expression. RNAi fruits exhibited enhanced shelf life, greater firmness, reduced reactive oxygen species (ROS) accumulation and increased resistance against post-harvest pathogens without affecting plant growth, fruit development, yield, or nutritional quality. To further explore the molecular mechanism of α-Man and β-Hex function, we purified and quantified N-glycans in RNAi fruits and other ripening-impaired mutants, identifying key N-glycan species. We also carried out iTRAQ-based quantitative proteome profiling to investigate the abundance of proteins in ripened fruit affected by silencing of α-Man and β-Hex. Molecular insights revealed that N-glycan processing and degradation are key events during ripening, influencing cell wall softening, fruit redox state, and post-harvest quality attributes. This study highlights the potential of co-silencing α-Man and β-Hex as a novel approach to extending the shelf life of fruits, regardless of their climacteric behavior, without compromising quality or yield.

Fruit ripening is regulated by a complex regulatory network, including internal factors and epigenetic modification. Until now, the role of histone methylation in grape fruit ripening is unclear, especially for H3K4me3 modification. H₂O₂ treatment promotes the ripening of grape berries, but how it regulates fruit ripening and whether it affects H3K4me3 modification is poorly understood. Here, to study the relationship between H₂O₂ and H3K4me3 modification in fruit ripening, a comprehensive analysis of anti-H3K4me3 ChIP-seq and RNA-seq of grape berries after H₂O₂ treatment was performed. The results revealed that H₂O₂ treatment led to changes in expression patterns and H3K4me3 modification in heat shock protein 18.2 (VvHSP18.2), ethylene-responsive transcription factor 75 (VvERF75), and E3 ubiquitin-protein ligase PUB23 (VvPUB23). Overexpression of VvHSP18.2 promoted grape fruit ripening. Among them, VvHSP18.2 positively regulates grape fruit ripening. The potential histone H3K4 demethyltransferase (lysine-specific demethylase JMJ14) with reduced expression after H₂O₂ treatment was further identified. VvJMJ14 is located in the cytoplasm and negatively regulates grape fruit ripening. VvJMJ14 does not directly interact with VvHSP18.2, VvERF75, and VvPUB23, but promotes their transcription by affecting the H3K4me3 levels in their promoter region after H₂O₂ treatment. Overall, these results demonstrate that VvJMJ14 is a H3K4 demethyltransferase that promotes the expression of VvHSP18.2, VvERF75, and VvPUB23 by regulating H3K4me3 levels, thereby accelerating H₂O₂-induced fruit ripening in grape. This study provides a reference for the study of H₂O₂ regulation of fruit ripening at the epigenetic regulation level.

The hypothesis that small peptides in the CLAVATA3/EMBRYO SURROUNDING REGION-RELATED (CLE) family are responsible for stomatal regulation under soil drying was tested in grapevine (Vitis vinifera L.). Potted Cabernet Sauvignon grapevines were subjected to water stress by withholding irrigation over a 10-day period followed by 6 days of holding stress and 10 days of recovery. Soil drying resulted in declines in leaf (Ψ_L) and stem (Ψ_S) water potentials and root and leaf hydraulic conductances. Near-complete stomatal closure occurred within 10 days of withholding water. Extending the duration of dry soil over an additional week had no additional effect on stomatal conductance (g_s), but decreased Ψ_L and Ψ_S. Xylem sap abscisic acid (ABA) increased during peak water stress and declined during extended stress. Transcripts of CLE1, CLE3 and CLE6 followed the same patterns as ABA and its transcript NCED1, increasing as the soil dried and decreasing upon soil rehydration. Gene expression of CLE9 increased in both roots and leaves in response to soil drying, but, in contrast to the other CLE peptides, it remained high in the roots even after the vines recovered from water stress. The results indicate that CLE9 may be a key root-to-shoot signal of soil drying in grapevine. Together with the putative regulation of leaf ABA by CLE peptides, stomatal regulation is suggested to be indirectly controlled by root and leaf CLE9 under soil drying. An overall model of hydraulic and chemical signalling in grapevine under water stress that incorporates the role of CLE peptides is proposed.

Rice (Oryza sativa L.), originating from tropical and subtropical regions, is a cold-sensitive and water-demanding crop whose yield and quality are severely compromised by chilling injury or water deficits during growth and development. In this study, we systematically characterized Cold and Drought Resistance 1 (OsCDR1), a nucleus-localized transcription activator belonging to the bZIP transcription factor family. OsCDR1 overexpression enhances rice tolerance to cold and drought stress, whereas knockout mutants of OsCDR1 exhibit reduced resistance to low temperatures and drought conditions. Furthermore, OsCDR1 positively regulates abscisic acid (ABA) signaling in rice, and mediates ABA-regulated drought tolerance responses in rice. Integrated RNA-seq and CUT&Tag analyses demonstrated that OsCDR1 coordinates with ABA-dependent (PIP2;2) and -independent genes (DREB1J). OsCDR1 specifically binds to the G-box cis-element in the promoters of PIP2;2 and DREB1J, thereby activating their transcription and regulating the abiotic stress responses in rice. Protein interaction analysis revealed that OsCDR1 interacts with the kinase OsMPK9 in vivo and in vitro, and a dual-luciferase reporter assay showed that OsMPK9 and OsCDR1 regulate the transcription of DREB1J and PIP2;2 in the same functional pathway. Overexpression of OsMPK9 inhibits ABA responses in rice and reduces cold and drought tolerance. Our findings establish the OsMPK9–OsCDR1 module as a critical hub connecting ABA signaling to abiotic stress resilience, providing new insights for breeding crops.

Plants have evolved intricate mechanisms to balance growth and defense through complex signaling networks. Previous studies have focused on aerial parts or crop yield, but little is known about the regulation of root growth under pathogen attack. Here, we report that the SERINE RICH ENDOGENOUS PEPTIDE12 (SCOOP12) immune signaling peptide regulates root meristem development via the receptor-like kinase MALE DISCOVERER 1-INTERACTING RECEPTOR-LIKE KINASE 2 (MIK2) and the MAPK cascade in Arabidopsis. We demonstrated that SCOOP12 treatment reduced the number of root meristematic cells by suppressing the expression of key molecular regulators, including PLETHORA1 (PLT1) and PLT2, which are essential for maintaining root stem cell niche (SCN) activity. Physiological and cell biological experiments revealed that MIK2 and MPK6 are required for SCOOP12-mediated root growth regulation, as the mik2 and mpk6 mutants presented reduced sensitivity to SCOOP12-induced effects. Further biochemical evidence indicates that MPK6 directly phosphorylates PLT1 and PLT2. The plt1-4 plt2-2 double mutant also presented diminished responses to SCOOP12, confirming the central role of PLT1/2 in this regulatory network. Our work elucidated a molecular pathway through which SCOOP12 modulates root meristem activity, providing insights into the trade-off between plant growth and immunity.