Plant, Cell & Environment最新文献

Mitochondrial activity must be tightly coordinated in plants to ensure that energy production is appropriately modulated in response to exogenous and endogenous signals. However, the underlying molecular mechanisms are largely unknown. Here, we investigated this issue by analysing the crosstalk between the nucleus and mitochondria mediated by pentatricopeptide repeat (PPR) proteins, which can regulate the proper function of mitochondrial electron transport chain complexes by affecting C-to-U editing of mitochondrial mRNA. More than 75% of PPR genes in maize (Zea mays) exhibited rhythmic expression, which changed in response to different light conditions. Analysis of mitochondrial RNA editing efficiency throughout the day identified editing sites displaying rhythmic variations, with many sites affecting protein function based on AlphaFold2 prediction. Notably, the peak phase of rhythmic RNA editing lagged behind that of PPR gene expression, suggesting that these two processes are tightly related. We also observed rhythmic expression of PPR genes and rhythmic editing of mitochondrial mRNA in rice (Oryza sativa). These findings suggest that PPR proteins might serve as integrators of environmental signals and transmit these signals to mitochondria by affecting RNA editing.

Angiosperm trees reorient their stems by producing tension wood (TW), a specialised xylem that generates contractile force. TW fibres develop a gelatinous (G) layer rich in cellulose, yet the molecular mechanisms governing G-layer formation remain poorly understood. COBRA-like genes encode glycosylphosphatidylinositol (GPI)-anchored proteins known to regulate cellulose deposition. Here, we functionally characterised PagCOBL5 in hybrid poplar (Populus alba × P. glandulosa) by identifying its upstream regulator and interaction partner. PagCOBL5 was preferentially expressed in mature xylem fibres, with high abundance in TW. Under mechanical stress, cobl5 knockout mutants exhibited impaired negative gravitropism and significantly thinner G-layer-phenotypes that were reversed in PagCOBL5-overexpressing lines. Furthermore, we found that the transcription factors PagLBD21 and PagLBD25 participate in the upstream negative regulation of PagCOBL5 expression, with the lbd21 lbd25/+ mutant exhibiting an enhanced gravitropic response and altered xylem cell differentiation. At the protein level, PagCOBL5 directly interacted with the cellulose synthase subunits PagCESA8b. This interaction positions PagCOBL5 as a key component recruited and spatially organised by the directionally moving cellulose synthase complex (CSC). Together, these results reveal a sophisticated regulatory and protein-interaction framework centred on PagCOBL5, providing pivotal molecular insights into how transcriptional modulation and cellulose synthase complexes coordinate G-layer formation and mechanical force generation during the gravitropic response.

Conifers exhibit distinct age-related transitions in wood development, yet the molecular mechanisms governing these changes remain poorly characterized. Here, we integrate multi-omics and functional analyses to unravel a transcriptional regulatory network underlying age-related wood formation in Chinese pine (Pinus tabuliformis). Cross-sectional and Raman microspectroscopy analyses revealed age-dependent enhancement of lignification and carbohydrate deposition in secondary xylem, coinciding with increased pith proportion. Temporal transcriptome profiling identified PtARN (AGE-RELATED NAC TRANSCRIPTION FACTOR) as a key age-correlated regulator, whose expression is directly activated by the conserved age timer PtDAL1 through promoter binding. We conducted a genome-wide identification of secondary cell wall biosynthesis pathway genes in P. tabuliformis, and genome-wide DNA affinity purification analysis uncovered that PtARN direct binding to promoters of 189 secondary cell wall biosynthesis genes. Strikingly, PtARN represses PtMYB162, a lignin biosynthesis suppressor, forming a regulatory cascade to fine-tune lignification. Collectively, our work establishes PtARN as a master regulator orchestrating age-dependent secondary cell wall deposition and lignification in the secondary xylem of Chinese pine, and delineates a previously uncharacterized PtDAL1-PtARN-mediated molecular regulatory network in P. tabuliformis. These findings significantly advance our understanding of the molecular regulatory network underlying wood formation in conifers, and bridging developmental timing with cell wall remodelling, and provide a robust framework for conifer-specific wood formation studies.

In climacteric fruits, ripening is triggered by a shift from auto-inhibitory to auto-catalytic ethylene production, but the activation of system II autocatalytic burst remains unclear. Here, we identified two MADS-box transcription factors, PpMADS2 and PpMADS4, as key positive regulators in peach (Prunus persica L. Batsch) ripening. Their expression increased during maturation and was induced by ethylene. Overexpression in pre-ripening fruit accelerated ethylene production, colour change, sugar accumulation and softening, while silencing delayed these processes. PpMADS2 interacts with PpMADS4 to form a functional complex which potentiates their activity, and they act by directly binding to and activating the promoters of ethylene biosynthetic genes PpACS1 and PpACO1, thereby promoting peach ethylene biosynthesis. Conversely, synthesis of ethylene in turn promotes the expression of PpMADS2/4 for positive feedback, amplifying ethylene production, contributing to the system II autocatalytic burst, ultimately leading to the maturation of peach fruit. This study provides a new insight into the MADS-box-ethylene regulatory network controlling climacteric fruit ripening.

Among various plant defence strategies, trichomes are tiny hair-like structures on the epidermis that aid in defence, environmental adaptation and the production of valuable secondary metabolites. This review features trichomes as frontline guards for plant survival, integrating their structural, physiological and metabolic roles in safeguarding against environmental adversity. We explore the developmental biology of trichomes, emphasising a multilayered regulatory network governed by transcriptional hierarchies, hormonal crosstalk, epigenetic remodelling and post-transcriptional modulation. Trichomes, divided into glandular and non-glandular types, function as physical shields and dynamic chemical interfaces, mediating defence against herbivores, pathogens, UV radiation and abiotic stresses such as drought and heavy metal exposure. Notably, glandular trichomes serve as specialised biosynthetic centres, producing high-value secondary metabolites, such as terpenoids, alkaloids and phenolics, which are increasingly harnessed in sustainable agriculture and green biotechnologies. Considering the broader context of climate resilience and bioeconomic innovation, this review describes trichomes as multifunctional and evolvable units of plant adaptation. It also highlights emerging research avenues such as single-cell omics, chromatin dynamics, metabolic and genetic engineering, which offer promising strategies for exploiting trichomes as a foundation for next-generation crop improvement and sustainable metabolic engineering.

The rapidly warming climate is driving increasingly frequent and intense heat waves worldwide, posing major challenges to plant metabolism and growth. Despite the central role of photosynthesis in plant growth, the effects of prolonged heat stress on the primary reactions of photosynthesis remain poorly understood. Here, we studied how long-term heat exposure affects growth and photosynthetic performance in the model plant Arabidopsis thaliana. Plants were exposed daily to high temperature (38°C) for 4 h throughout the growth period. Conflicting to earlier studies, we show that PSII-LHCII remain relatively intact under prolonged heat despite slightly reduced ∆F/F_m', relative electron transfer rate (rETRII) and proportion of open reaction centers (qL). Strikingly, the content of the Cytochrome b₆f complex, which mediates electron transfer between the photosystems, was reduced by 30-40%. This leads to more oxidized downstream electron acceptors and prevents PSI over-reduction in conditions where carbon assimilation is inhibited.

For sessile plants, survival hinges on the dynamic allocation of limited resources among growth, defence and reproduction. We propose that the plant Hippo signalling network has evolved into a central strategic hub governing these fundamental trade-offs. Building upon its evolutionarily conserved pleiotropic roles, this hub in plants has acquired unique regulatory capacities. It integrates hormonal, developmental and stress signals to act as a cellular decision-maker, exhibiting organizational complexity that includes parallel branches and context-specific outputs. Plant-specific innovations-including a direct SIK1-MOB1 interaction that bypasses the canonical SAV1 scaffold, dual-specificity NDR kinases and MOB1A/B heterodimer formation-underpin this adaptive evolution. Crucially, the antagonism between SIK1 and MOB1 fine-tunes the jasmonate pathway, functioning as a molecular 'rheostat' for the growth-defence balance. Viewing the plant Hippo pathway through the lens of 'adaptive trade-off management' not only redefines its biological significance but also charts a new research agenda. We outline priorities to quantify signal flux through the hub, resolve the structure of plant-specific complexes and manipulate this decision-making system to engineer crops with optimized resilience and yield.