Cassava (Manihot esculenta Crantz) exhibits high photosynthetic efficiency and remarkable starch accumulation in its storage roots. The effective loading of photosynthates into the phloem from mesophyll cells in leaves i...Cassava (Manihot esculenta Crantz) exhibits high photosynthetic efficiency and remarkable starch accumulation in its storage roots. The effective loading of photosynthates into the phloem from mesophyll cells in leaves is a critical determinant of yield; however, this process remains poorly understood. In this study, we propose a theoretical model of apoplastic sucrose phloem loading in cassava based on a multitechnique approach. The concentration of primary photoassimilates in leaf veins, analyzed using a [14C]CO2 tracer, and the existence of few plasmodesmata between bundle sheath cells/phloem parenchyma cells and sieve element-companion cell (SE-CC) complexes in minor veins suggest characteristic apoplastic phloem loading in cassava. We identified five sucrose transporters (MeSUTs) in the cassava genome, among which MeSUT1a exhibited the highest expression and the strongest sucrose intake activity. Subcellular localization analyses showed that MeSUT1a specifically localizes in the plasma membrane of the SE-CC complexes and that sugar transporter (MeSWEET2a) localizes on parenchyma cells, suggesting potential functional synergy. Interference with MeSUT1a expression led to a reduction in sucrose loading efficiency by more than 50%, resulting in abnormal sucrose and transient starch accumulation. This interference subsequently impaired chloroplast development and leaf photosynthesis, ultimately reducing storage root yield and starch content. RNA-seq analysis of MeSUT1a transgenic lines further revealed remarkable transcriptional changes in genes associated with sugar transport, carbohydrate metabolism, and photosynthesis. These results establish that MeSUT1a is essential for driving sucrose phloem loading and plays a key role in the distribution of photosynthetic assimilates and the coordination of source-sink dynamics in cassava.
The development of embryo sacs, a process regulated by an array of genes, significantly impacts seed setting rate and yield production in rice (Oryza sativa L.). The establishment of the single archesporial cell and sing...The development of embryo sacs, a process regulated by an array of genes, significantly impacts seed setting rate and yield production in rice (Oryza sativa L.). The establishment of the single archesporial cell and single functional megaspore are crucial events during embryo sac development. Nevertheless, the molecular mechanisms controlling the number of archesporial cell and functional megaspore number remain poorly understood. In this study, we identified the FEMALE GAMETOPHYTE GUARD gene (OsFGG), encoding a protein in the kinesin family, whose mutation displayed increased archesporial cells, degenerated megaspores, and increased megaspores, finally leading to degenerated or double-female-gametophyte embryo sacs (two nonholonomic embryo sacs coexisting within a single ovule). RNA-seq revealed dysregulated expression levels of genes relative to female reproduction (such as OsAGG1, OsMSP1) and protein processing in endoplasmic reticulum (like OsFes1C and OsDER1) in fgg mutants. Physical interactions between OsFGG and OsERECTA2 (OsER2) was demonstrated by using yeast two-hybrid, bimolecular fluorescence complementation, and luciferase complementation imaging assays. The OsFGG proteins and interacted complex of OsFGG and OsER2 mainly localized at endoplasmic reticulum. Additionally, oser2 and fgg oser2 mutants exhibited similar abnormalities in archesporial cells and functional megaspores as observed in fgg mutants. These findings present cytological characteristics and molecular insights into female reproduction and underscore the cooperative role of OsFGG and OsER2 in sustaining single archesporial cell and single functional megaspore and subsequent embryo sac development in rice.
DMI3 (Doesn't Make Infections 3), a calcium/calmodulin-dependent protein kinase (CCaMK), decodes rhizobia-induced Ca2+ signals through phosphorylation of its interacting partner, IPD3, thereby initiating root nodule symb...DMI3 (Doesn't Make Infections 3), a calcium/calmodulin-dependent protein kinase (CCaMK), decodes rhizobia-induced Ca2+ signals through phosphorylation of its interacting partner, IPD3, thereby initiating root nodule symbiosis (RNS). However, the precise mechanism by which DMI3 activates this pathway remains unclear. Here, we show that phosphorylation of a triplet motif (S343S344T345) located at the C-terminus of the calmodulin-binding domain acts as a molecular switch. We identified T345 as a phosphorylation site that exhibits regulatory functions similar to those of S343 and S344. Phosphomimic mutations at any single residue of the three sites blocked DMI3-dependent nodulation, indicating that the kinase must initially remain non-phosphorylated at these positions. Conversely, simultaneous phosphorylation of at least two residues was required for symbiotic activity, revealing a transition from a phosphorylation-free state to a hyperphosphorylated (simultaneous phosphorylation of at least two residues) status at these sites. Phosphomimic mutations within the triplet enhanced DMI3 autophosphorylation (auto-P) but severely impaired its interaction with Ca2+/CaM and IPD3. In addition, the physical interaction between DMI3 and IPD3 suppressed IPD3-triggered MtNIN transcription and nodulation, indicating that DMI3 also acts as a negative regulator by sequestering activated IPD3. Thus, we propose a model in which repeated auto-P at the triplet contributes to RNS activation by dissociating the CaM-DMI3-IPD3 complex, thereby releasing phosphorylated and activated IPD3 to initiate the downstream transcriptional cascade. Our findings uncover a dual role for DMI3-as both a kinase and a scaffold-and clarify how auto-P within the triplet motif licenses IPD3 to trigger RNS.
In plants, reactive oxygen species (ROS) play a crucial role in rapidly responding to biotic stresses, thus contributing to the establishment of immune networks and plant resistance against pathogen attack. The two-layer...In plants, reactive oxygen species (ROS) play a crucial role in rapidly responding to biotic stresses, thus contributing to the establishment of immune networks and plant resistance against pathogen attack. The two-layered plant immune system consists of the cell-surface pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) and intracellular effector-triggered immunity (ETI), both of which are associated with ROS burst. Mitochondria, serving as a major source of intracellular ROS, are key to plant immunity, and their function depends on the RNA processing of mitochondrial genes. The DEAD-box RNA helicase PUTATIVE MITOCHONDRIAL RNA HELICASE 2 (PMH2) is required for efficient group Ⅱ intron splicing in mitochondria; however, how PMH2-mediated fine RNA splicing contributes to plant immunity remains unknown. Here, we revealed a function of PMH2 in ETI using Arabidopsis thaliana. ETI activation led to the PMH2-mediated reduction in splicing efficiency of cox2, which encodes the subunit of mitochondrial respiratory chain complex IV, and the activity of complex IV, thereby promoting the generation of mtROS. Moreover, PMH2-mediated mtROS facilitated the expression of the nuclear immunity genes. These results collectively suggest that PMH2 contributes to specific mitochondrial RNA splicing and fine-tunes the mitochondrial ROS burst, therefore maintaining robust plant immunity. Our study provides the mechanism of RNA helicase linking RNA processing and mitochondrial dynamics to plant ETI.
Synthetic biology enables efficient production of valuable compounds in biological systems, including plants that capture atmospheric CO2 to synthesize and accumulate abundant and diverse specialized metabolites. Most pl...Synthetic biology enables efficient production of valuable compounds in biological systems, including plants that capture atmospheric CO2 to synthesize and accumulate abundant and diverse specialized metabolites. Most plant synthetic biology studies to produce specialized metabolites have primarily used Nicotiana benthamiana as an underpinning metabolic chassis, due to its rapid agroinfiltration method, leaving much of the metabolic potential of other plant species underexplored. Here we engineered three distinct plant chassis-Arabidopsis, tobacco and soybean-by stably introducing an optimized betalain biosynthetic pathway and analyzed their metabolic impacts. Betalains are tyrosine-derived pigments, which are used as natural red and yellow food dyes with rapidly growing demand due to a recent regulatory shift. We fine-tuned metabolic balances by redesigning the RUBY betalain construct (RUBYv2), adding an extra DODA enzyme ("pull") and modulating tyrosine precursor supply ("push") using two different promoters. The "push-and-pull (push+pull)" lines produced higher betalain levels than the "pull" lines in all three species, even exceeding those of beet roots. While Arabidopsis and tobacco "push+pull" lines driven by a strong promoter showed dwarfism, corresponding soybean lines did not show severe growth defects, suggesting greater tolerance of soybean to the engineered pathway. This study demonstrates that careful plant chassis selection, coupled with precise control of pathway expression, is essential for maximizing the yield of target specialized metabolites, such as betalain pigments, without impairing overall plant growth.
KARRIKIN INSENSITIVE 2 (KAI2)/DWARF14-LIKE (D14L) plays key roles in land plant development, environmental responses, and the establishment of arbuscular mycorrhizal symbiosis, likely acting as the receptor for unidentif...KARRIKIN INSENSITIVE 2 (KAI2)/DWARF14-LIKE (D14L) plays key roles in land plant development, environmental responses, and the establishment of arbuscular mycorrhizal symbiosis, likely acting as the receptor for unidentified signaling molecules termed KAI2 ligands (KLs). KL perception by KAI2/D14L promotes DWARF3 (D3)/MORE AXILLARY GROWTH2 (MAX2) F-box protein-mediated ubiquitination of SUPPRESSOR OF MAX2 1 (SMAX1) proteins, thereby transducing the KL signals. Although genetic and in vivo assays have demonstrated the functions of these components, the biochemical details of their interactions remain elusive. Here we investigated physical interactions between rice (Oryza sativa) D14L, D3, and OsSMAX1 in vitro using desmethyl germinone (dMGer), a recently developed KL analog. dMGer elicited KL responses in rice with higher activity and pathway specificity than a widely used KL analog (-)-GR24. dMGer, but not (-)-GR24, directly bound to D14L and promoted the interaction between D14L and D3 in vitro. The interaction between D14L and OsSMAX1 was also enhanced by dMGer. Furthermore, we identified the domain of OsSMAX1 that distinguishes it from its paralog DWARF53 (D53), which is associated with the strigolactone signaling complex. These findings suggest a model of the interactions among KL signaling components and highlight the role of the ligand in the signaling complex.
Sex differentiation is a crucial developmental process accompanied by tightly regulated anther development or its selective abortion. In litchi (Litchi chinensis), anthers develop normally in male flowers but are defecti...Sex differentiation is a crucial developmental process accompanied by tightly regulated anther development or its selective abortion. In litchi (Litchi chinensis), anthers develop normally in male flowers but are defective in female flowers, with impaired pollen development. However, the underlying regulatory mechanism remains unclear. We report here that transcription factor SPOROCYTELESS/NOZZLE (SPL/NZZ) is critical for anther and pollen development in litchi. Notably, LcSPL/NZZ shows persistently high expression throughout anther development in female flowers. Ectopic overexpression of LcSPL/NZZ suppresses filament elongation, reduces anther size, impairs pollen development, and ultimately causes male sterility. We further show that the misexpression of LcSPL/NZZ in female flowers is likely mediated by a bHLH transcription factor (bHLH91). Mechanistically, LcbHLH91 binds the LcSPL/NZZ promoter to modulate its expression and physically interacts with LcSPL/NZZ in the nucleus, thereby enhancing its expression and protein activity. Phylogenetic and promoter analyses further indicate that the bHLH91-SPL/NZZ regulatory module is conserved within the Sapindaceae. Results obtained in this study imply a novel regulatory circuit controlling sex differentiation and anther development in litchi and related species.
David LC, Deslandes-Hérold G, Hostettler C
… +11 more, Bischof S, Fischer-Stettler M, Carluccio AV, Pfister B, George GM, Wang W, Stavolone L, Gisel A, Bull SE, Abt MR, Zeeman SC
The carbohydrate-rich storage roots of cassava (Manihot esculenta) are among the world's most vital staple foods, providing food security and income for hundreds of millions of people-primarily smallholder farmers in tro...The carbohydrate-rich storage roots of cassava (Manihot esculenta) are among the world's most vital staple foods, providing food security and income for hundreds of millions of people-primarily smallholder farmers in tropical and subtropical regions. Cassava is also a major source of starch for both food and industrial applications. Root yield is largely determined by starch content, which acts as the main sink for photoassimilates during vegetative growth. In addition, stored starch serves as a carbohydrate reservoir that supports regrowth after stress events, such as drought or shoot pruning, or during stem propagation. To investigate source-sink dynamics and identify key factors in sink metabolism, transcriptomic and proteomic analyses of cassava storage roots were conducted following shoot pruning. This perturbation led to a significant reduction in root starch content and triggered widespread transcriptional reprogramming, restricting respiration and growth. Notably, key starch biosynthesis genes were repressed, while starch degradation genes-including the plastidial α-AMYLASE3 A (AMY3A)-were induced. To confirm the role of AMY3 in root starch breakdown, AMY3A-suppressed cassava lines were generated via RNA interference and evaluated under both greenhouse and field conditions. These lines exhibited up to a 7.5-fold reduction in starch mobilization following pruning compared to controls, demonstrating AMY3's key function in storage root starch degradation-a role that contrasts with its redundancy in systems like transitory starch degradation in Arabidopsis leaves. Crucially, AMY3A suppression did not impair cassava stem cutting regrowth, highlighting it as a promising target for improving cassava root traits and advancing food security.
Grain chalkiness is attributable to polygenic traits, including inadequate photosynthate supply, imbalanced source-sink dynamics, or restricted biosynthesis of storage materials. Nevertheless, the precise regulatory mech...Grain chalkiness is attributable to polygenic traits, including inadequate photosynthate supply, imbalanced source-sink dynamics, or restricted biosynthesis of storage materials. Nevertheless, the precise regulatory mechanism of chalkiness formation remains to be elucidated. In this study, a CRISPR/Cas9 gene editing mutant (oss40-2cr) of a novel transcription factor OsS40-2 in rice exhibited a longer and stay-green flag leaf, a lower CO2 assimilation rate, as well as a transparent endosperm, accompanying by augmented grain weight and diminished grain size compared to the japonica rice cultivar Nipponbare (NIP). The complementation line oss40-2com partially restored the oss40-2cr phenotype to its NIP state. The integrative analysis of the transcriptome and the tsCUT&Tag dataset of the flag leaf and grain at varying developmental stages of the oss40-2cr relative to NIP demonstrated that OsS40-2 functions both as an activator and as a repressor for various downstream genes, thereby regulating enzyme activities related to catalysis, kinase, and transferase in the carbohydrate and protein metabolic processes. OsS40-2 directly targeted and activated the transcription of the precursor of the Rubisco large subunit 1 (OspreRBCL1) before pollination and that of the sucrose transporter OsSWEET7d before seed maturation. However, OsS40-2 exerts a contrary effect by repressing the transcription of OsUGT201 and OsGPIT1 gene at the seed development stage. OsS40-2 plays a critical node linking photosynthetic efficiency, grain filling, and seed component metabolism through the maintenance of source-sink homeostasis in a developmentally dependent manner, thereby affecting grain weight and grain quality.
Leaf phenology may influence the development of wood structure and hydraulic function across growing seasons, yet the roles of green-up, green-down, and growing season length in regulating xylem anatomy remain unclear. W...Leaf phenology may influence the development of wood structure and hydraulic function across growing seasons, yet the roles of green-up, green-down, and growing season length in regulating xylem anatomy remain unclear. We quantified annual wood anatomy, leaf phenology, and growth in a whole-ecosystem experiment with 5 warming levels (up to +9 °C) and 2 CO2 levels (ambient and +500 ppm) in Picea mariana (conservative spruce) and Larix laricina (acquisitive larch). We identified a phenology-tracheid-growth spectrum, reflecting a trade-off between hydraulic safety (thicker walls, higher tracheid density, and later green-up) and fast growth (wider tracheids, delayed green-down, and longer growing seasons). In spruce, earlier green-up, longer growing seasons, and later green-down increased the latewood hydraulic diameter more than the earlywood. In larch, earlier green-up increased earlywood hydraulic diameter, while later green-down increased latewood mechanical safety via thicker walls. Larch exhibited greater phenological sensitivity to elevated CO2 in regulating wood anatomy than spruce. Warming indirectly increased spruce growth by extending the growing season, which increased the latewood hydraulic diameter and subsequently enhanced overall growth. Warming directly increased larch growth but not through enhanced earlywood hydraulic conductivity. These findings demonstrate the role of divergent phenological adjustments in hydraulic function, with implications for boreal carbon and water fluxes.
Dong T, Sack L, Nadal M
… +14 more, Xu W, Niinemets Ü, Hammond WM, Brodribb TJ, Wu F, Zhang N, Gao Y, Xiong D, Liu H, Fan D, Baird A, Onoda Y, Flexas J, Yan Z
Understanding how leaf water relations integrate with carbon economy is central to plant physiological ecology and to predictions of vegetation responses to environmental change, yet the degree of their coordination rema...Understanding how leaf water relations integrate with carbon economy is central to plant physiological ecology and to predictions of vegetation responses to environmental change, yet the degree of their coordination remains debated. We investigated relationships between leaf pressure-volume (PV) traits (leaf-specific capacitance at full turgor per dry mass (C*ft,mass), osmotic potential at the turgor loss point (πtlp), and other PV traits) and leaf economics spectrum (LES) traits (leaf nitrogen content, specific leaf area, and photosynthetic capacity) across temperate, subtropical, and tropical forests. These two suites of traits exhibited statistically partial coordination: C*ft,mass was tightly coupled with LES traits, whereas πtlp was independent of the LES framework, and this partial coupling was primarily driven by leaf saturated water content. Notably, coordination was strongest at the subtropical site, where conservative strategies strengthened the integration between PV and LES traits, thereby improving resource-use efficiency. This partial coupling provides insights into the multidimensional nature of plant functional strategies and the mechanisms underpinning species coexistence across forest types.
The model green alga Chlamydomonas reinhardtii has a pyrenoid within chloroplast for photosynthetic CO2 fixation under limiting CO2 conditions and its chloroplast is an ideal chassis for engineering photosynthetic module...The model green alga Chlamydomonas reinhardtii has a pyrenoid within chloroplast for photosynthetic CO2 fixation under limiting CO2 conditions and its chloroplast is an ideal chassis for engineering photosynthetic modules. In contrast, carboxysomes are bacterial microcompartments that encapsulate Rubisco for CO2 fixation. The aim of the present study was to determine if a bacterial carboxysome or its components can replace pyrenoid and function to allow Chlamydomonas growth powered by photosynthesis. We replaced the Chlamydomonas endogenous RbcL gene with cbbL and cbbS from the chemoautotrophic bacterium Halothiobacillus neapolitanus, resulting in proper assembly of the heterologous Rubisco with slightly lower enzymatic activity than the endogenous Rubisco. We next expressed 4 or 6 carboxysome-related genes and observed the formation of carboxysome-like structures in chloroplast. Photoautotrophic growth of transformants were enabled under high CO2 (∼5%) conditions, but not in ambient air (∼0.04% CO2). Our study serves as a demonstration on how carboxysomes can be partially reconstituted in eukaryotic algae, which have great uses in bioindustry. The single-cell nature of Chlamydomonas allows it to be used as a testbed for optimizing the sequences of the genes required for heterologous carboxysome formation and for future improvements in CO2-fixation efficiency and incorporation of diverse metabolic pathways in chloroplasts.
Increases in chloroplast activity will lead to increases in the qualities and yields of crop plants. A variant of a subspecies of Brassica rapa named wutacai from the Yangtze River Basin accumulates relatively high level...Increases in chloroplast activity will lead to increases in the qualities and yields of crop plants. A variant of a subspecies of Brassica rapa named wutacai from the Yangtze River Basin accumulates relatively high levels of chlorophyll and thus may contribute to our understanding of mechanisms that control chlorophyll and chloroplast content in plants. To test this idea, we crossed a dark Chinese cabbage probably derived from wutacai with a variety of Chinese cabbage that accumulates less chlorophyll. Our characterization of the progeny indicated that 2 genes, DARK WUTACAI LEAF (DWL) 1 and DWL2, explain most of the variation in chlorophyll content. We mapped a semidominant allele of DWL1 to a 150-kb interval. Although we expected to find a mutation in a gene from dark Chinese cabbage, we instead found a missense mutation in the FERROCHELATASE 2 (FC2) gene from the pale variety of Chinese cabbage. This mutation leads to a G411R substitution in a poorly understood domain named region II that was reported to promote ferrochelatase activity and stability. However, the G411R substitution did not influence the catalytic parameters of FC2. High-level expression of FC2 from Chinese cabbage in Arabidopsis reduced the proliferation of chloroplasts, attenuated the development of the thylakoid membranes, and led to chlorophyll deficiencies but did not reduce heme content or the levels of cytochromes in the thylakoid membranes. Our data indicate that the G411R substitution influences an activity unrelated to FC2 activity that is critical for the development and proliferation of chloroplasts in leaves.
Leaf senescence is a highly regulated biological process that marks the final stage of leaf development. The initiation and progression of this process are precisely controlled by complex regulatory networks involving nu...Leaf senescence is a highly regulated biological process that marks the final stage of leaf development. The initiation and progression of this process are precisely controlled by complex regulatory networks involving numerous endogenous factors. Here, we demonstrate that ONAC005 functions as a negative regulator of the onset of leaf senescence. ONAC005 expression gradually declines during both natural and dark-induced senescence. onac005 mutants generated by T-DNA insertional and CRISPR/Cas9-mediated mutagenesis exhibited precocious leaf yellowing under natural and dark-induced conditions, while ONAC005-overexpressing plants retained leaf greenness much longer than the wild type. ONAC005 overexpression downregulates the expression of senescence-associated genes and chlorophyll degradation genes, whereas onac005 mutation upregulates their expression. ONAC005 reduces the response to abscisic acid, thereby delaying abscisic acid-induced senescence. Through in vivo and in vitro DNA-binding assays, we demonstrated that ONAC005 directly binds to the promoters of OsNAP and OsNAP-regulated chlorophyll degradation genes, leading to transcriptional repression. Furthermore, we identified specific DNA motifs that ONAC005 preferentially recognizes. Taken together, these results suggest that ONAC005 acts as a repressor of leaf senescence by repressing the OsNAP-mediated senescence signaling pathway.
Liu W, Liu H, Liu X
… +11 more, Yue Z, Yan J, Wei L, Wang H, Zhao P, Bian G, Zhang Q, Huang Y, Zhang Q, Zheng T, Li P
Plant Physiol
· 2026 Jun · PMID 42234825
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The Prunus mume species has undergone a long process of domestication and introduction in China, resulting in marked differences in freezing tolerance among populations across a latitudinal gradient of approximately 1,00...The Prunus mume species has undergone a long process of domestication and introduction in China, resulting in marked differences in freezing tolerance among populations across a latitudinal gradient of approximately 1,000 km. However, the introduction and domestication process is time-consuming, constraining the efficiency of species introduction. In this study, P. mume samples with the same genetic background spanning over 1,000 km from north to south were selected as experimental materials. The molecular mechanisms underlying cold-acclimation-mediated freeze tolerance in P. mume were investigated using multiomics high-throughput sequencing and molecular biology techniques. The cold-acclimated plant material exhibited enhanced freezing tolerance. Cold acclimation substantially enhanced transcriptional reprogramming under cold stress, accompanied by the remodeling of chromatin states in the promoter region. A variety of cis-regulatory elements were identified in the open chromatin regions of cold-acclimated plant materials, including G-box, ABRE, and other stress-responsive elements. The bZIP transcription factor PmGBF1, as a key regulatory node, directly regulates the expression of the cold shock protein gene PmCSL by binding to G-box elements to regulate freezing tolerance. This study reveals the molecular mechanism underlying cold acclimation mediated by the PmGBF1-PmCSL pathway in regulating P. mume freezing tolerance, providing an epigenetic theoretical basis and genetic resources for cold-acclimation breeding of freezing tolerance in woody plants.
Soil contamination with heavy metals and salinity threatens global crop production. Heavy metal and salinity stresses induce reactive oxygen species (ROSs) burst. How ROS homeostasis and signaling are maintained under th...Soil contamination with heavy metals and salinity threatens global crop production. Heavy metal and salinity stresses induce reactive oxygen species (ROSs) burst. How ROS homeostasis and signaling are maintained under these stresses are not fully understood. Among the 11 genes encoding the plasma membrane intrinsic proteins (PIPs), we found that expression of OsPIP2;1 and OsPIP2;2 in rice roots was upregulated by exposure to heavy metals (Cd, Cu, or Pb) and salinity. Both genes were mainly expressed in the outer cell layers and the stele of roots. OsPIP2;1 and OsPIP2;2 were permeable to H2O2. Knockout of both genes increased cytosolic ROS accumulation but decreased apoplastic ROS levels, resulting in a greater inhibition of root and shoot growth by heavy metals and salinity. The effect from knocking out both OsPIP2;1 and OsPIP2;2 was additive of single gene knockouts. The mutant phenotypes were rescued by chemical ROS scavenging, suggesting that the increased sensitivity to heavy metals and salinity in the knockout mutants is attributed to increased cytosolic ROS accumulation. Furthermore, knockout of both OsPIP2;1 and OsPIP2;2 impaired the propagation of systemic ROS signaling from stress-exposed to unexposed roots, compromising the ability to proliferate lateral roots in the stress-free zone, a stress avoidance strategy observed in wild-type plants. Taken together, OsPIP2;1 and OsPIP2;2 play dual roles in alleviating oxidative damage caused by heavy metals and salinity by transporting ROS out of the cytoplasm and in transducing long-distance systemic ROS signaling to trigger root system remodeling and stress avoidance in response to localized stress.
Wen Q, Wang Y, Huang GC
… +5 more, Pan HY, Tang YY, Bie LH, Liu LN, Gao J
Plant Physiol
· 2026 Jun · PMID 42234821
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Carboxysomes are specialized bacterial microcompartments (BMCs) for CO2 assimilation in cyanobacteria and many chemoautotrophs. Selective transport of gas molecules and metabolites across the carboxysome shell plays an e...Carboxysomes are specialized bacterial microcompartments (BMCs) for CO2 assimilation in cyanobacteria and many chemoautotrophs. Selective transport of gas molecules and metabolites across the carboxysome shell plays an essential role in creating a high-CO2 environment around Rubisco and ensuring efficient metabolite flux. However, the molecular mechanisms underlying this specific permeability remain elusive. Using integrated computational approaches, including all-atom molecular dynamics (MD) simulations, self-random acceleration MD simulations, umbrella sampling and targeted MD simulations, we systematically investigated the permeation pathways of large anionic metabolites ribulose-1,5-bisphosphate (RuBP) and 3-phosphoglycerate (3-PGA) through the α-carboxysome shell protein CsoS1D, which exhibits a trimer-of-dimer architecture and an enlarged central pore compared with hexameric and pentameric shell proteins. The results indicate that the central pore of CsoS1D serves as the primary conduit for the translocation of bulky metabolites RuBP and 3-PGA and reveal a 3-stage "air-lock" transport mechanism driven by electrostatic interactions. Moreover, the shallow free-energy landscape for channel gating enables the pore to undergo frequent, thermally driven transitions between open and closed states, implementing a conformational selection transport model independent of ligand binding. Our analysis further revealed 5 conserved residues that establish an electrostatic transport pathway within trimeric shell proteins, suggesting that this permeability mechanism represents a generalizable design principle across diverse BMCs. By elucidating shell protein permeability mechanisms at atomic resolution, this study lays the framework for understanding carboxysome physiology and guides the rational engineering of carboxysome permeability to facilitate system-level metabolic modeling and optimization of synthetic carboxysomes for biotechnological applications.