Plant, Cell & Environment最新文献

Antarctica's extreme cold challenges terrestrial life. In plants, β-ketoacyl-CoA synthase (KCS) is a critical enzyme for very long-chain fatty acids (VLCFAs) biosynthesis. However, the role of KCS genes in Antarctic mosses-the dominant terrestrial flora in this harsh ecosystem-remains poorly understood. Here, we performed a comparative analysis of cold tolerance and VLCFAs profiles between the Antarctic moss Pohlia nutans and the model bryophyte Physcomitrella patens, combined with functional characterization of the P. nutans KCS gene family (PnKCS1-19). P. nutans demonstrated superior growth rates and cold tolerance compared to P. patens. Furthermore, the PnKCS gene family has undergone substantial expansion via whole genome duplication, with intra-clade sequence homology exceeding 95.0%. Notably, heterologous expression of the PnKCS gene family in both wild-type and mutant yeast systems revealed novel VLCFAs profiles in some yeast strains, reflecting the distinct catalytic capabilities of PnKCSs. Heterologous of PnKCS7 and PnKCS8 in P. patens, which catalyzed the synthesis of a novel VLCFA component (C30:0) in wild yeast, enhanced the cold tolerance and total VLCFAs content of plant. These findings reveal the mechanism of Antarctic P. nutans adaptation via KCS-mediated VLCFAs synthesis, underscoring the ecological role of lipid remodeling.

Plant branching, encompassing both vegetative and reproductive forms, is a complex and crucial process that shapes overall architecture and determines crop yield and biomass. MicroRNAs (miRNAs) have emerged as master regulators in fine-tuning the intricate genetic and hormonal networks that govern plant branching. This review systematically synthesises recent advances in understanding how miRNA-target gene modules regulate essential pathways to orchestrate the branching patterns. We highlight a central insight that specific miRNA families form hierarchical, stage-specific networks that facilitate the independent optimisation of vegetative and reproductive branching. Furthermore, we explore the potential applications of miRNA manipulation in optimising branching architecture to improve crop yield. By critically evaluating strategies such as artificial miRNAs, target mimics and CRISPR/Cas9 genome editing, we discuss how modulating miRNA networks can engineer ideal plant architecture. Finally, we provide a forward-looking perspective on overcoming challenges in miRNA-based crop improvement, emphasising the integration of single-cell omics and epigenetic insights to achieve precise genetic modifications. This review underscores the transformative potential of miRNAs in designing future crops for enhanced productivity.

Cadmium (Cd) toxicity threatens rice production and food safety. While ethylene-responsive transcription factors (ERFs) are involved in stress responses, their role in Cd detoxification in rice is unclear. This study identifies OsERF104 as a key positive regulator of Cd tolerance in rice. We demonstrate that OsERF104, induced by Cd stress in an H₂O₂-dependent manner, directly activates the expression of OsPDR5 and OsPDR20, two plasma membrane ABC transporters responsible for Cd efflux. Loss-of-function OsERF104 showed increased Cd sensitivity and accumulation, while complementation restored wild-type phenotypes. Transcriptomic analysis revealed that OsERF104 is essential for Cd-inducible expression of OsPDR5 and OsPDR20. OsERF104 directly binds to GCC-box elements in the promoters of OsPDR5 and OsPDR20, activating their transcription, as confirmed by ChIP-qPCR, EMSA, Y1H, and luciferase assays. Overexpression of OsPDR20 in the oserf104 mutant rescued the Cd-sensitive phenotype. Collectively, our findings uncover a novel OsERF104-OsPDR5/OsPDR20 module that curtails Cd accumulation and enhances Cd tolerance, representing a promising target for breeding low-Cd rice.

Light enhances protein translation, enabling young seedlings to rapidly and timely acquire photosynthetic capacities. Sequential phosphorylation of ribosomal protein S6 (RPS6) was implicated in the light-enhanced translation; however, the exact phosphorylation sites and the biological relevance of RPS6 multi-phosphorylation in seedling development remain elusive. Here, we report the identification and quantification of RPS6A residues that exhibit dynamic, differential phosphorylation in seedlings grown in darkness or during the initial exposure to light. Among six C-terminal sites, four serine residues, serine-229 (S229), S231, S237 and S240, serve as seed sites for light-regulated sequential phosphorylation. Combinatorial mutations of the C-terminal serines/threonine (S/T) to aspartic acids (phospho-mimic) or alanines (phospho-null) partially rescued the reduced hypocotyl elongation in etiolated rps6a seedlings. De-etiolating rps6a seedlings expressing phospho-mimic or phospho-null RPS6A showed decreased photosynthetic protein accumulation and reduced translation capacity. These findings indicate that fully tunable phosphorylation of RPS6A is essential for its complete function in hypocotyl elongation, translation efficiency, and photosynthetic capacities in both etiolated and de-etiolating seedlings. Our results demonstrate that the structural integrity of the C-terminal S/T residues is vital for establishing precise phosphorylation codes of RPS6A in light or dark conditions. Even a single substitution at these conserved residues can disrupt the light-regulated phosphorylation-dephosphorylation dynamics of RPS6A, thereby impairing its functions. This also explains the evolutionary conservation and importance of these C-terminal S/T residues to warrant young seedlings' capacities to adapt effectively to changing light environments in their natural habitats.

Vitamin E (tocochromanols), a vital lipid-soluble antioxidant, is often deficient in maize-based diets. Our objective was to identify potential genomic regions associated with tocochromanols variation and evaluate the potential of genomic predictions for its improvement. We assessed 1044 tropical maize inbreds from three panels across multiple environments, and genotyped them with high-density single-nucleotide polymorphisms. Across panels, we identified 50 causal loci, including 15 in a combined panel associated with three grain tocochromanol components. Associated loci showed strong positive allelic effects (1.12- to 2.72-fold increment due to favourable allele) for improving tocochromanol content. Notably, four loci were associated with α-tocotrienol, and three loci with α-tocopherol were found to be stable, and one pleiotropic locus influenced both. Underlying candidate genes are enriched in cellular, catalytic, biosynthetic and metabolic processes, with 14 involved in the tocochromanol biosynthesis pathway. Favourable haplotypes on chromosomes 5 and 7, notably increased α-tocopherol (6.12-16.19 µg/g) and γ-tocopherol (32.12-102.31 µg/g) levels, respectively. Genomic prediction models proved useful in predicting tocochromanols with moderate-to-high prediction accuracies (0.43-0.52), demonstrating their potential to develop elite, high-tocochromanol lines. Our results provided valuable insights into the genetic architecture of tocochromanols and support accelerating biofortification through genome-wide selection to improve vitamin E levels in tropical maize.

Leguminous crop rotation (LC) and conservation tillage (CT) are nature-based solutions to mitigate climate change. Previous studies have shown significant variations in crop productivity and soil organic carbon (SOC) under LC and CT, largely influenced by site-specific conditions. However, the mechanisms driving the interactions between LC and CT to enhance compatibility across diverse environmental conditions remain unclear. This study conducted a meta-analysis combined with machine learning, using a high-resolution global database of 271 site experiments to evaluate the impact of LC, CT, and their interaction on crop yield and SOC, clarify the underlying mechanisms, and assess their global potential. Results indicated synergistic effects of LC and CT led to additional increases of up to 13.4% in yield and 8.6% in SOC. These benefits were more pronounced in warm-humid regions, with low initial soil fertility, fine soil texture, and low nitrogen (N) input. Among key factors influencing these interactive effects, N input and the initial soil carbon to nitrogen (C/N) ratio emerged as the top two determinants for crop yield and SOC changes. Globally, integrating LC and CT in farmlands could potentially increase crop production and SOC stock by 16.9% and 7.6%, respectively. Looking ahead, these practices could enhance crop production by up to 400 Tg (24.6%) and SOC stock by 8.4 Pg (10.0%), helping to address climate change under various future scenarios. These results highlight that optimising N input and the initial soil C/N ratio through LC-CT integration achieves a win-win scenario of increased crop yield and enhanced SOC sequestration, with significant potential under future climate conditions. This study provides a scientific basis for developing targeted farmland management strategies tailored to diverse environmental conditions worldwide.

Ethylene plays an indispensable role in regulating plant growth and stress responses. However, the mechanisms underlying the regulation of Na⁺/H⁺ homoeostasis by ethylene and subsequent mediation of maize growth under salt stress remain unclear. ZmACO2, which encodes ethylene biosynthesis enzyme 1-aminocyclopropane-1-carboxylate oxidase2, is induced by salt stress. Thus, ZmACO2-overexpressing (ACO2-OE) and mutant (aco2-cr) plants were used to investigate how ethylene regulates Na⁺/H⁺ homoeostasis in maize under salt stress. The aco2-cr mutants exhibited significantly lower Na⁺ accumulation and Na⁺/K⁺ ratios than the wild-type and ACO2-OE plants. This phenotype was attributed to their higher expression of ZmSOS1 and ZmHKT1, which increased root net Na⁺ efflux by 20.65% and decreased Na⁺ transport from roots to shoots by 42.49% (p < 0.001), respectively. Compared to the other plants, aco2-cr mutants showed higher ZmMHA2 expression and plasma membrane H⁺-ATPase activities, which promoted net root H⁺ efflux to provide a greater H⁺ proton gradient for salt-overly-sensitive 1 (SOS1). Inhibition efficiencies of Na⁺ efflux and H⁺ influx by sodium orthovanadate were lower in aco2-cr mutants than in ACO2-OE and wild-type plants under salt stress; however, ACO2-OE plants showed a salt-sensitive phenotype. Overall, these findings showed that salt-induced ethylene inhibited plasma membrane H⁺-ATPase and SOS1 from disrupting Na⁺/H⁺ homoeostasis, thereby decreasing Na⁺ efflux in maize roots and also provided a strategy to improve salt tolerance by optimising ethylene levels in maize.

Vascular plants may employ several physiological mechanisms to stabilize their protein contents as atmospheric CO₂ concentrations change over a day, year, decade, or century. One mechanism is that plants may rely more on soil ammonium as their nitrogen source when CO₂ increases. Another is that plants may convert more nitrate into amino acids in their roots. A third is that plants may increase the ratio of manganese over magnesium in their chloroplasts and accelerate a previously unrecognized biochemical cycle that generates organic acids such as malate instead of carbohydrates. This proposed cycle coordinates photorespiration with the metabolism of nitrogen and sulfur, the malate valve, the pentose phosphate shunt, the C₁ pathway, the C₂ glycolate pathway, and the C₃ carbon fixation pathway. The three mechanisms tend to improve the energy efficiency of most vascular plants.