J. Exp. Bot. [JOURNAL]
Sun
200 papers
Heat stress-induced remodelling of lipid and microRNA networks in Brassica napus L. germinated pollen and pollen-derived small extracellular vesicles.
D'Agostino A, Di Marco G, Pontecorvi C … +8 more , Suanno C, Ruggirello F, Zuccheri G, Ulian G, Valdrè G, Canini A, Del Duca S, Gismondi A
J Exp Bot · 2026 Jun · PMID 42333468 · Publisher ↗
Heat stress (HS) is a primary factor limiting plant reproductive success, severely affecting pollen production and performance. In order to clarify the molecular alterations underlying HS-induced male sterility, lipidomi...
Heat stress (HS) is a primary factor limiting plant reproductive success, severely affecting pollen production and performance. In order to clarify the molecular alterations underlying HS-induced male sterility, lipidomic and small RNA sequencing analyses were conducted on hydrated pollen (HP), germinated pollen (GP), pollensomes (PS), and the vesicle-free medium of Brassica napus L. cv Phoenix CL grown under both control and HS conditions. HS significantly reduced pollen germinability and increased PS externalization. Although particle size remained unchanged, a significant increase in PS abundance was observed in HS-derived samples. Lipid profiling revealed significant HS-induced remodelling across all samples, including an increase in saturated fatty acids in HP and GP. Notably, triacontanoic acid, the dominant lipid in control PS, was lost under HS conditions and was replaced by oleic acid. Small RNA sequencing identified 70 miRNAs, 61 of which were differentially expressed. HP showed the strongest response to HS, while PS showed opposite trends, suggesting the selective retention or export of miRNAs. HS increased the levels of miR160, miR6030a and miR319a in PS, while the release of miR399 shifted from being vesicular to non-vesicular. Target prediction revealed that these miRNAs regulate pathways associated with development, hormones, vesicles, and lipids. Overall, this study reveals that HS remodels lipid metabolism and miRNA-mediated regulation in pollen and PS, providing molecular signatures for improving crop heat tolerance.
Genetic mechanisms underlying temperature-mediated changes in flower development.
Laitinen RAE, Elomaa P
J Exp Bot · 2026 Jun · PMID 42322188 · Publisher ↗
Flower morphologies are remarkably diverse in nature, reflecting their specialized role in plant reproduction. In the context of climate change, understanding the impact of temperature on flower development is essential...
Flower morphologies are remarkably diverse in nature, reflecting their specialized role in plant reproduction. In the context of climate change, understanding the impact of temperature on flower development is essential for predicting plant adaptation to future climates, and improving crop resilience. The genetic basis of flower development is well-understood, but less is known of the impact of environmental variation on floral traits and the genetic mechanisms mediating such responses. This gap in knowledge may stem from the longstanding view that flower development is buffered against environmental influences due to its essential role in fitness. However, growing evidence indicates that floral traits can be environmentally plastic, adjusting in response to factors such as temperature, light, and water availability. This review gathers current knowledge on the temperature effects of floral traits and explores the genes and mechanisms underlying the temperature-mediated changes in flower development. We highlight trait-specific responses and consider the adaptive consequences of temperature-mediated trait variation.
Expanding the scope of precision editing in seaweeds through the application of a novel CRISPR-Associated Nuclease 12a (Cas12a) -aligned CRISPR system in Ulva prolifera.
Qin Z, Surnido W, Hozumi S … +4 more , Hirano T, Sawatsubashi S, Mizuta H, Uji T
J Exp Bot · 2026 Jun · PMID 42319116 · Publisher ↗
Seaweeds, such as the fast-growing green alga Ulva prolifera, can be harnessed as valuable marine crops. The lack of scalable genome-editing tools hampers functional genomics to explore and elucidate algal molecular path...
Seaweeds, such as the fast-growing green alga Ulva prolifera, can be harnessed as valuable marine crops. The lack of scalable genome-editing tools hampers functional genomics to explore and elucidate algal molecular pathways with industrial importance. Here, we expanded precision genome modification in seaweeds by successfully demonstrating gene editing with a transgene-free AT-rich-targeting Cas system in U. prolifera. By evaluating various delivery buffers, comparing different Cas systems, and optimizing incubation temperatures, we determined suitable conditions for higher applicability of a novel Cas12a-aligned ST8 editor. We obtained more than 50 ST8-mediated knock-out mutants of a toxin-based endogenous marker gene, UpAPT, at 28℃ post-delivery incubations. Our work diversified the applicable genome editing tools in seaweeds, advancing algal functional genomics, and providing more strategies to precisely target unexplored seaweed resources.
The transcriptional regulator MOS1 attenuates salinity stress-induced seed germination inhibition via negative feedback regulation of ABA signaling in Arabidopsis.
Xu Y, Chen X, Luo L … +6 more , Huang J, Zhu F, Wang Z, Wu D, Hong L, Zhang N
J Exp Bot · 2026 Jun · PMID 42319112 · Publisher ↗
Seed germination is inhibited by salt stress, and this inhibition is known to be mainly mediated by the plant hormone abscisic acid (ABA). Whether and how this inhibition is fine-tuned is not fully understood. Here, we i...
Seed germination is inhibited by salt stress, and this inhibition is known to be mainly mediated by the plant hormone abscisic acid (ABA). Whether and how this inhibition is fine-tuned is not fully understood. Here, we identified MODIFIER OF snc1-1 (MOS1) as an attenuator of salt-induced inhibition of seed germination. MOS1 expression was induced by salt, and this induction was partly dependent on ABA biosynthesis and signaling. The mos1 mutant showed hypersensitivity to salt stress during seed germination compared to the wild-type, accompanied by higher ABA accumulation and stronger salt-induced expression of ABA biosynthesis and signaling genes. Genetic analysis suggested that MOS1 limits both salt-induced ABA biosynthesis and ABA responsiveness. Moreover, ABI5 directly activated MOS1 expression, whereas ABI5 transcript and protein accumulated to higher levels in mos1 under salt stress. In addition, MOS1 expression was inhibited by the germination-promoting hormone gibberellin (GA), and MOS1 helped maintain GA biosynthesis. Together, these findings suggest that MOS1 attenuates salt-induced inhibition of seed germination, at least in part, through ABI5-linked negative feedback regulation of ABA signaling and modulation of GA biosynthesis.
Chloroplast proteostasis: Coupling chlorophyll and carotenoid metabolism and chlorophyll-binding protein homeostasis in plants.
Fu D, Zhao C, Huang X … +1 more , Wang P
J Exp Bot · 2026 Jun · PMID 42317008 · Publisher ↗
Photosynthetic efficiency depends on the homeostatic accumulation of chlorophyll-binding proteins in photosystems and their light-harvesting antenna complexes within the thylakoid membrane. The assembly of these proteins...
Photosynthetic efficiency depends on the homeostatic accumulation of chlorophyll-binding proteins in photosystems and their light-harvesting antenna complexes within the thylakoid membrane. The assembly of these proteins requires stoichiometric amounts of chlorophylls and carotenoids, which not only drive light harvesting and photochemistry but also promote the folding, membrane insertion, and stability of chlorophyll-binding proteins. Because free pigments and unassembled apoproteins are potentially deleterious, optimal photosynthetic performance requires tight coordination between pigment metabolism and the biogenesis, repair, and turnover of chlorophyll-binding proteins. Emerging evidence indicates that chloroplast proteostasis, mediated by molecular chaperones, assembly factors, and proteolytic machinery, is the key post-translational mechanism linking these processes. This review summarizes how proteostasis networks coordinate chlorophyll and carotenoid metabolism with the biogenesis, assembly, and maintenance of chlorophyll-binding proteins, and highlights the auxiliary factors that couple pigment supply, protein quality control, and photosystem function. Collectively, these insights provide a foundation for future studies of photosynthetic acclimation and plastid development and may formulate effective strategies to improve photosynthesis and chloroplast performance in crops.
A viral protein promotes host L-asparaginase activity and weakens the asparagine-induced resistance pathway for the benefit of virus infection.
He Y, Chen X, Guo Y … +7 more , Zhao Y, Ye S, Zhao Y, Jiang L, Chen X, Zhu Q, Chen J
J Exp Bot · 2026 Jun · PMID 42316991 · Publisher ↗
Amino acids are not only essential for plant nutrition but also serve as critical immune signaling molecules, particularly during pathogen invasion. Pathogens can manipulate amino acid metabolic pathways to counteract ho...
Amino acids are not only essential for plant nutrition but also serve as critical immune signaling molecules, particularly during pathogen invasion. Pathogens can manipulate amino acid metabolic pathways to counteract host immune defenses, yet the underlying mechanisms remain poorly understood. Here, we demonstrate that the Pepper mild mottle virus (PMMoV) 126 kDa protein interacts with host L-asparaginase (LA), identified as a negative regulator of antiviral defense. LA converts asparagine (Asn) to aspartic acid (Asp). Exogenous application of Asn markedly enhanced resistance to PMMoV, whereas Asp produced the opposite effect. Transcriptomic analysis revealed that Asn activates key antiviral immune pathways involving salicylic acid (SA), ethylene (Eth), and reactive oxygen species (ROS), while Asp suppresses them. Further experiments showed that the 126 kDa protein binds directly to the LA active region, enhancing its enzymatic activity and promoting Asn-to-Asp conversion, thereby weakening immune signaling. This process may also involve the VSR (viral suppressor of RNA silencing) function of the 126 kDa protein. Notably, LA also interacts with pathogenic proteins from other RNA viruses (e.g., CMV 2b, RSV NS3, TBSV P19) and facilitates Tomato bush stunt virus (TBSV) accumulation. This study elucidates how viruses exploit amino acid metabolism to promote infection and provides a novel strategy for environmentally friendly control of pepper viral diseases.
SUMO proteases implement regulatory logic across Hormonal Networks to enact Plant Stress Responses.
Long X, Ghosh S, Sadanandom A
J Exp Bot · 2026 Jun · PMID 42313783 · Publisher ↗
Plants rely on precisely regulated hormonal networks to balance defence and growth during stress. In this context, the SUMO proteases that govern deSUMOylation have emerged as the critical regulatory system. In this revi...
Plants rely on precisely regulated hormonal networks to balance defence and growth during stress. In this context, the SUMO proteases that govern deSUMOylation have emerged as the critical regulatory system. In this review, we outline how SUMO proteases modulate stress response by selectively deSUMOylating key components of hormone biosynthesis, perception and signalling across major phytohormonal pathways, such as Jasmonic acid (JA), Salicylic acid (SA), abscisic acid (ABA), gibberellin (GA), auxin and brassinosteroid (BR). We highlight the role of closely related SUMO proteases subsets such as OTS1/OTS2, SPF1/SPF2 and ESD4/ELS1 in reprogramming hormonal hierarchies to fine-tune defence outputs. Additionally, we illustrate that distinct SUMO protease subsets operate in a cell-type-specific manner, to coordinate hormonal pathways. Overall, our findings position SUMO proteases as dynamic modulators that translate environmental cues into balanced hormonal outputs. Despite the recent progress, the substrate specificity, interaction dynamics and spatiotemporal regulation of these proteases are open areas for further exploration. Understanding how SUMO proteases reshape hormonal networks will unravel novel strategies to generate climate resilient crops.
Quantitative light element profiling in plant tissues with monochromatic X-ray fluorescence analysis: a new frontier for abiotic stress studies.
Kahlon PS, Kokkinopoulou P, Alfageme SB … +5 more , Leong CK, Zhang C, Chen Z, Testerink C, van der Ent A
J Exp Bot · 2026 Jun · PMID 42307654 · Publisher ↗
Determining elemental concentrations in plant tissues is essential for physiological studies on abiotic stress. However, high-throughput routine analysis of light elements (sodium to calcium) in plants is challenging due...
Determining elemental concentrations in plant tissues is essential for physiological studies on abiotic stress. However, high-throughput routine analysis of light elements (sodium to calcium) in plants is challenging due to the need for complete sample dissolution and expensive and time-consuming inductively coupled plasma-mass-spectrometry (ICP-MS). Ion chromatography and ion-selective electrodes are low-cost methods but suffer from major drawbacks, including limited throughput and time-consuming sample preparation. This study reports on a new methodology for quantitative analysis of light elements in plants using monochromatic X-ray fluorescence (MXRF) analysis. We quantitatively assessed sodium and potassium uptake in Arabidopsis thaliana, Oryza sativa and Lactuca sativa in salinity treatments. The new method provides reliable results from samples as small as 1 mg, making it suitable for analysis at the seedling stage. This is enabled by the high sensitivity of the system and optimized sample preparation that ensures sufficient signal even at low sample masses. We tested the accuracy and precision of the technique for other light elements to demonstrate its broad applicability. The results show that the method delivers rapid, non-destructive, and extraction-free light element analysis on small samples highly correlating with ICP-MS. The monochromatic XRF method provides accurate measurements and reproducible results for studying salinity tolerance ideally suited for investigating elemental composition of early plant developmental stages, offering new possibilities for research into early stimuli responses.
Single-nucleus sequencing reveals the developmental trajectory and transcriptional regulatory networks of trichome in Artemisia annua.
Lv Z, Li C, Jiang R … +4 more , Jia X, Di P, Xiao Y, Chen W
J Exp Bot · 2026 Jun · PMID 42307650 · Publisher ↗
Sweet wormwood (Artemisia annua) produces and deposits artemisinin in its glandular trichomes while the molecular mechanisms of trichome development remain poorly understood. Here, we conduct single-nucleus RNA sequencin...
Sweet wormwood (Artemisia annua) produces and deposits artemisinin in its glandular trichomes while the molecular mechanisms of trichome development remain poorly understood. Here, we conduct single-nucleus RNA sequencing of 10-day-old A. annua seedlings, depicting the specific expression of trichome cell in leaves. The reconstruction of developmental trajectory of trichome cells not only identifies novel expressed genes, but also elucidates trichome development involved in photosynthesis, auxin biosynthesis, and cutin biosynthesis. By integrating the developmental trajectory of trichome cells with histochemical assays, we identified several genes not previously reported to be involved in trichome development, such as TOE3, MYB1, WRKY10, and ZNF. Moreover, we identified a gene in subcluster 0 encoding a previously unknown WD40 repeat nuclear protein, WDR1, potentially involved in trichome development. We showed that WDR1 not only interacts with SPL9 and enhances its ability to activate HD1 expression, but also directly binds to HD1 itself, thereby forming a regulatory feedback loop that modulates trichome development in A. annua. This study reveals a previously uncharacterized gene that regulates trichome development in A. annua based on a single-cell transcriptome analysis. The results presented here offer unprecedented insight into a new pathway for enhancing trichome density and artemisinin production.
Membrane lipid properties in photosynthetic responses to environmental changes.
Kim E, Kobayashi K
J Exp Bot · 2026 Jun · PMID 42304952 · Publisher ↗
Oxygenic photosynthesis relies on multisubunit protein complexes embedded in the thylakoid membrane, which is distinguished by its unique lipid composition consisting of galactolipids and sulfolipids together with phosph...
Oxygenic photosynthesis relies on multisubunit protein complexes embedded in the thylakoid membrane, which is distinguished by its unique lipid composition consisting of galactolipids and sulfolipids together with phosphatidylglycerol rather than typical phospholipids. Emerging structural and biophysical evidence indicates that these lipids are involved in dynamic regulation of photosynthesis. Lipids act as structural cofactors to stabilize the assembly of photosystem complexes and also as modulators of membrane properties such as fluidity, polymorphism, and thickness, which directly impact photosynthetic processes. These physical properties of the thylakoid membrane are regulated according to environmental conditions. Fatty acid unsaturation modifies lipid bilayer fluidity and thereby mitigates the effects of temperature on membranes. The ratio of non-bilayer-forming to bilayer-forming lipids contributes to lipid phase transitions required for environmental responses of thylakoid proteins. Furthermore, changes in thylakoid membrane thickness regulate protein-protein assembly, such as the aggregation of light-harvesting complex II through hydrophobic mismatch, thereby modulating the light-harvesting system. In this review, we integrate recent findings to highlight the role of thylakoid lipids as modulators of photosynthetic protein interactions and their conformational and functional states, providing key insights into the functional regulation of the photosynthetic apparatus in response to environmental changes.
No evidence of xylem embolism refilling during recovery from drought stress in intact sunflowers.
Stewart JJ, Allen BS, Polutchko SK … +3 more , Hunter C, Ocheltree TW, Gleason SM
J Exp Bot · 2026 Jun · PMID 42304951 · Publisher ↗
Refilling of xylem embolism during recovery from drought has been studied for decades, although the legitimacy of supporting evidence has been debated in recent years due to potentially widespread methodological artifact...
Refilling of xylem embolism during recovery from drought has been studied for decades, although the legitimacy of supporting evidence has been debated in recent years due to potentially widespread methodological artifacts associated with destructive sampling. Evidence from multiple destructive/indirect measurements of embolism suggests sunflower can refill, but more recent evidence suggests this species is particularly susceptible to artifacts that cause the appearance of refilling. Here, we investigated drought-induced xylem embolism and its potential reversibility in intact sunflowers using low-radiation micro-computed tomography (µCT). While plants were drying, turgor loss and stomatal closure occurred at ca. -1.0 MPa, whereas comparable losses of photosystem II efficiency as well as leaf and stem xylem embolism occurred at ca. -1.5 MPa. After re-watering, xylem embolism that accumulated in stems and leaves during the drought event did not reverse despite significant recovery of transpiration and photosynthesis. We found no evidence of xylem embolism refilling in sunflowers, highlighting the potential widespread nature of methodological artifacts and the need to revisit conclusions of "refilling" in other species as well as physiological and developmental consequences of irreversible embolism.
Immature fruit abscission is triggered by hormonal changes in the seed coat of avocado.
Haberman A, Goetz M, Böttcher C … +3 more , Hands P, Maffei SM, Smith HM
J Exp Bot · 2026 Jun · PMID 42304883 · Publisher ↗
Avocado (Persea americana Mill.) is an economically important tree crop that exhibits a high rate of immature fruit abscission (IFA), reducing yield. As the seed coat derived from recently abscised fruitlets displays a s...
Avocado (Persea americana Mill.) is an economically important tree crop that exhibits a high rate of immature fruit abscission (IFA), reducing yield. As the seed coat derived from recently abscised fruitlets displays a senescence phenotype, we hypothesized that the seed coat plays a critical role in initiating IFA. Here, we show that fruitlets fated to abscise undergo growth arrest before shrinking and detaching from the tree. Comparative RNAseq analysis indicates that growth arrest is associated with a transcriptome reprogramming that is first initiated in the seed coat then transmitted to pericarp and embryo. Gene expression and hormone profiling results indicate that fruitlet growth arrest is associated with a decline in auxin activity and an increase in abscisic acid, the ethylene precursor, 1-aminocyclopropane-1-carboxylic acid, and the bioactive jasmonate, jasmonoyl-isoleucine, in the seed coat. At a late stage of growth arrest, transcriptomic signatures further suggest that a dormancy-like program of development is induced in the seed and a senescence phenotype is activated in the seed coat. Together, our data indicate that avocado IFA is initiated by hormone-driven transcriptome reprogramming that functions to transition the seed coat to a senescence program of development, which induces growth arrest, seed dormancy and ultimately, fruitlet abscission.
Stress granules as central players in the plant stress response.
Solis-Miranda J, Gonzalez-Rodriguez S, Rubio-Ramos R … +2 more , Delgado-Romero D, Gutierrez-Beltran E
J Exp Bot · 2026 Jun · PMID 42302304 · Publisher ↗
Stress granules (SGs) are conserved biomolecular condensates that assemble in response to environmental stress. SGs were initially described as sites of translational arrest containing stalled mRNAs and RNA-binding prote...
Stress granules (SGs) are conserved biomolecular condensates that assemble in response to environmental stress. SGs were initially described as sites of translational arrest containing stalled mRNAs and RNA-binding proteins (RBPs). However, accumulating evidence indicates that SGs play a broader and more active role during stress responses. Rather than acting as passive repositories, SGs have emerged as dynamic hubs that contribute to the coordination of multiple cellular processes, enabling rapid adjustment to adverse conditions. In this context, studies in animal systems have redefined SGs as central hubs that coordinate key cellular processes, including signalling, cellular homeostasis, and metabolic adaptation. Similarly, emerging evidence in plants suggests that SGs function as important regulators of stress responses, contributing to the reorganization of cellular activities required for adaptation. Despite these advances, key questions remain regarding the mechanisms underlying SG assembly, selectivity, and functional outputs in plant cells.
Hydraulic failure in Cerrado plants is reduced by plasticity in water loss, not water storage or embolism vulnerability.
Aun MA, Farnese FS, Fernandes VAB … +10 more , Loram-Lourenço L, Filho VMA, Fontineles da Silva ML, Zorger BB, Silva FG, Franco AC, DaMatta FM, Torres-Ruiz JM, Cochard H, Menezes-Silva PE
J Exp Bot · 2026 Jun · PMID 42299898 · Publisher ↗
Increasingly frequent and intense drought events are challenging the survival of several forest species worldwide. Yet, the extent to which plants can postpone drought-induced mortality (DIM) through plastic adjustments...
Increasingly frequent and intense drought events are challenging the survival of several forest species worldwide. Yet, the extent to which plants can postpone drought-induced mortality (DIM) through plastic adjustments in traits linked to hydraulic failure (HF) remains unclear. Here, we explored how the coordinated drought-induced plasticity in traits controlling water loss (WL), water storage capacity (WS), and drought tolerance (DT) influences the time to HF in a group of representative Cerrado species. Long-term exposure to drought induced marked morphoanatomical alterations in all the studied species, which minimized the impairments to their growth, while simultaneously reducing the risk of HF. However, those changes occurred almost exclusively in traits associated with the control of WL, both before and after complete stomatal closure, whereas traits related to WS and DT exhibited limited phenotypic plasticity. Despite this limited plasticity in hydraulic traits, all species showed inherently high hydraulic safety margins, achieved through a combination of early stomatal closure and high resistance to embolism, likely reflecting evolutionary pressures imposed by recurrent seasonal droughts in the Cerrado. Overall, our results highlight the necessity to embrace the complexity of drought acclimation mechanisms to improve the predictions of plant performance and survival under extreme weather events.
SNAP30 forms a SNARE complex with VAMP726 and SYP131 and mediates vesicle secretion at the plasma membrane of the Arabidopsis pollen tube tip.
Gao Y, Zhu D, Liu X … +3 more , Li J, Zhao F, Li Y
J Exp Bot · 2026 Jun · PMID 42299879 · Publisher ↗
SNAREs are important proteins that mediate the fusion of vesicles with target membranes in eukaryotic cells. The fusion of secretory vesicles with the plasma membrane is the basis of pollen tube tip growth. However, the...
SNAREs are important proteins that mediate the fusion of vesicles with target membranes in eukaryotic cells. The fusion of secretory vesicles with the plasma membrane is the basis of pollen tube tip growth. However, the role of Qbc SNARE SNAP30 in Arabidopsis pollen tubes has not yet been reported, and the intact SNARE complex that regulates exocytosis at the pollen tube tip has yet to be determined. Our study revealed that the deletion of SNAP30 inhibited the tip growth of Arabidopsis pollen tubes. Fluorescence recovery after photobleaching (FRAP) experiments indicated that SNAP30 plays an important role in exocytosis at the Arabidopsis pollen tube tip. Confocal microscopy revealed that SNAP30 and SYP131 or VAMP726 colocalize to the plasma membrane at the tips of Arabidopsis pollen tubes. Furthermore, we found that SNAP30 can interact with the Qa-SNARE SYP131 and R-SNARE VAMP726. In addition, SNAP30 can form a SNARE complex with VAMP726 and SYP131. These results suggest that SNAP30 forms a SNARE complex with VAMP726 and SYP131 to mediate vesicle secretion at the plasma membrane of Arabidopsis pollen tube tip. These results also indicate that the molecular mechanism of vesicle secretion may be evolutionarily conserved between animal nerve cells and plant pollen tubes.
Spatial specificity of MADS-box transcription factors in developing floral organs.
Désert E, Vandenbussche M, Monniaux M
J Exp Bot · 2026 Jun · PMID 42299624 · Publisher ↗
Floral homeotic genes, most of them encoding MADS-box transcription factors, are classically pictured as early specifiers of floral organ identity, as implied by the famous ABC model. Yet, floral homeotic genes remain ex...
Floral homeotic genes, most of them encoding MADS-box transcription factors, are classically pictured as early specifiers of floral organ identity, as implied by the famous ABC model. Yet, floral homeotic genes remain expressed throughout floral organ development, sometimes with a cell type-specific expression pattern, and late functions have been firmly established for some of these genes. Here, we review how floral homeotic MADS-box genes are expressed in floral organs during their development, highlighting general trends for their spatial or temporal-specific expression, in particular for B-class genes in petals that are systematically distally-enriched. We focus on chosen examples from the literature to discuss the different roles associated with this specific expression, and we then explore the possible molecular mechanisms by which MADS-box transcription factors can adopt spatially or temporally restricted functions in floral organs, either by a simple restriction of their presence, or by a different mode of action in given cell types. Altogether, this review highlights that late roles of floral MADS-box transcription factors have been largely unexplored, and that these regulators might have multiple different functions according to the cell types in which they are present.
Biomolecular Condensates in Plant Stress and Development: Recent Advances and Emerging Concepts.
Maruri-Lopez I, Hernandez-Sanchez IE, Muraleedharan M … +1 more , Chodasiewicz M
J Exp Bot · 2026 Jun · PMID 42276972 · Publisher ↗
Biomolecular condensates have emerged as a central paradigm for understanding how plant cells organize biochemical processes without membrane boundaries, particularly under fluctuating environmental conditions. In plants...
Biomolecular condensates have emerged as a central paradigm for understanding how plant cells organize biochemical processes without membrane boundaries, particularly under fluctuating environmental conditions. In plants, many condensates are thought to form through liquid-liquid phase separation and related demixing behaviors, enabling the selective concentration of proteins and RNAs into dynamic assemblies. This mesoscale organization provides an efficient strategy to buffer acute stress, protect macromolecules, and reprogram gene expression across spatial and temporal scales. Here, we synthesize current knowledge of condensate functions in plant development and stress responses, with a focus on Arabidopsis thaliana, where mechanistic insights are most advanced. We first outline the biophysical principles underlying condensate formation, emphasizing multivalent protein-protein and protein-RNA interactions, intrinsically disordered regions, and prion-like or low-complexity domains that enable reversible assemblies with distinct material properties. We then discuss condensates in plant development, highlighting hydration-associated assemblies in seeds, as well as condensation-based regulation of light signaling, auxin pathways, and flowering time. Next, we examine condensates as key hubs of stress adaptation, including stress granules and processing bodies, nuclear assemblies, and emerging evidence for organellar condensates in chloroplasts, which may exhibit distinct biophysical characteristics. Finally, we review the experimental toolkits used to study condensates in plants, ranging from live-cell imaging and fluorescence recovery after photobleaching (FRAP) to in vitro reconstitution, proximity labeling, particle enrichment strategies, and RNA-centric profiling approaches, while emphasizing important technical considerations and limitations. We conclude by outlining key open questions such how plants dynamically regulate condensate assembly and disassembly in vivo, how condensates interface with proteostasis and organelle function, and how this layer of regulation may contribute to plant resilience in the context of climate change.
Roots of Wheat and Rice maintain Gravitropic Setpoint Angles.
Stemp-Walsh F, Kaye R, Kitching Z … +4 more , King A, Del Bianco M, Roychoudhry S, Kepinski S
J Exp Bot · 2026 Jun · PMID 42274371 · Publisher ↗
Root growth angle is a key determinant of root system architecture, nutrient capture efficiency and therefore yield. Yet the mechanisms governing non-vertical growth in cereal roots remain poorly understood. Here, we inv...
Root growth angle is a key determinant of root system architecture, nutrient capture efficiency and therefore yield. Yet the mechanisms governing non-vertical growth in cereal roots remain poorly understood. Here, we investigated if cereal roots maintain Gravitropic Setpoint Angles (GSAs) and the hormonal regulatory processes underpinning GSA maintenance in cereals. Firstly, we found that both wheat seminal roots and rice crown roots actively return toward their original growth angles following displacement, consistent with true GSA maintenance. Next, we show that removal of a stable reference to gravity through clinorotation resulted in a characteristic outward curvature in all root types, indicating the presence of an antigravitropic offset similar to that described in Arabidopsis. Exogenous auxin treatment induced steeper rooting in both species, suggesting conserved hormonal regulatory mechanisms of GSA in both monocots and dicots. Interestingly, lateral root GSAs displayed species-specific differences: wheat laterals returned to their GSAs more effectively than rice laterals, which showed slower and incomplete responses. Together, these findings establish that cereal roots maintain GSAs through gravity-dependent and auxin-regulated mechanisms, providing a novel framework for understanding and manipulating root system architecture in monocot crops.
Cytokinin regulates flowering time in Arabidopsis thaliana through the gibberellin pathway.
Werner S, Bartrina I, Tarkowská D … +2 more , Werner T, Schmülling T
J Exp Bot · 2026 Jun · PMID 42274237 · Publisher ↗
Cytokinin and gibberellin are two plant hormones promoting flowering in Arabidopsis thaliana grown under short-day conditions. The activities of both hormones depend on similar signaling components, including several ele...
Cytokinin and gibberellin are two plant hormones promoting flowering in Arabidopsis thaliana grown under short-day conditions. The activities of both hormones depend on similar signaling components, including several elements of the age pathway. However, to date, the interaction between cytokinin and gibberellin in regulating the transition to flowering remains unknown. In this work, we show that exogenous treatment of late-flowering or non-flowering cytokinin mutants by gibberellin restores their ability to flower. In contrast, the promotion of flowering by cytokinin is suppressed by mutations in gibberellin biosynthesis genes, and cytokinin-deficient plants show reduced expression of these genes. Consistently, cytokinin-deficient plants show an altered gibberellin homeostasis in leaves and shoot apices. Simultaneous mutation of the DELLA genes GAI and RGA, or of RGL1 and RGL3, caused earlier flowering in cytokinin receptor mutants. This is consistent with their downstream activity in response to cytokinin and reveals a previously unrecognized role for these genes in regulating flowering time. Together, the results indicate that cytokinin acts upstream of a redundant network of gibberellin metabolism and signaling genes and suggest that hormonal crosstalk occurs in both leaves and the shoot apical meristem. Cytokinin action through different elements of the gibberellin system underscores the complexity of hormonal interactions in controlling the floral transition.
Cell wall dynamics and biomechanics of root hair morphogenesis.
Zambare V, Anderson CT
J Exp Bot · 2026 Jun · PMID 42274226 · Publisher ↗
Root hairs are specialized extensions of root epidermal cells that allow plants to explore and attach to the soil. They exhibit polar growth under the influence of isotropic turgor pressure thanks to the anisotropic natu...
Root hairs are specialized extensions of root epidermal cells that allow plants to explore and attach to the soil. They exhibit polar growth under the influence of isotropic turgor pressure thanks to the anisotropic nature of their cell walls. This unidirectional growth is regulated by myriad subcellular factors such as microtubule and actin dynamics, a tip-focused calcium gradient, and the interplays between gradients of apoplastic and cytosolic pH and reactive oxygen species. All these players also influence cell wall dynamics by forming feedback loops that modulate cell wall assembly and modification, which are essential processes for root hair morphogenesis. In this review we discuss the functions of cell wall polysaccharides and proteins and their impacts on the biomechanics of root hair growth at each developmental stage. We also discuss important open questions and technical advancements in studying root hair mechanobiology. Despite significant progress, many of the spatiotemporal changes that occur in the cell walls of root hairs remain undiscovered. Therefore, we highlight ongoing research and exciting future avenues that will shed light on cell wall dynamics, biomechanics, and mechanobiology of root hair morphogenesis.
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