Environmental and Experimental Botany
○ Elsevier BV
Preprints posted in the last 30 days, ranked by how well they match Environmental and Experimental Botany's content profile, based on 12 papers previously published here. The average preprint has a 0.01% match score for this journal, so anything above that is already an above-average fit.
Chaudhary, C.; Guttula, P.; Agrawal, K.; Subudhi, P. K.; Gartia, M. R.
Show abstract
Rice (Oryza sativa) is highly sensitive to salinity, yet the metabolic mechanisms underlying salt tolerance remains incompletely understood. In this study, we performed leaf tissue-specific untargeted metabolomic profiling of the salt-tolerant introgression line JN100 (JN), its donor parent Nona Bokra (NB), and its recurrent parent Jupiter (JU) to characterize metabolic responses to salt stress. Comparative analysis identified differentially accumulated metabolites (DAMs) spanning diverse chemical classes, including amino acids, sugars and carbohydrates, lipids, organic acids, cofactors, electron carriers, and nucleotides. Under salt stress (SS), 201 DAMs (89 upregulated and 112 downregulated) were detected in JN relative to JU. Notably, metabolites such as allantoin, glycitin, nicotinamide ribotide, D-arabinono-1,4-lactone, violanthin, L-methionine S-oxide, ribitol, lysine, rutin, glutamine, pantothenic acid, and quinic acid, showed significant differential accumulation. Pathway enrichment analysis revealed significant enrichment of arginine biosynthesis, purine metabolism, and alanine, aspartate, and glutamate metabolism, indicating extensive reprogramming of nitrogen and energy-associated metabolic pathways under salinity stress. Integration of transcriptomic and metabolomic datasets from the SS experiments further identified ten differentially expressed genes (DEGs) associated with the metabolite network in the JN vs. JU comparison. Among these, OsDHQDT/SDH, OsFd-GOGAT, phenylalanyl-tRNA synthetase, OsP5CS1, OsP5CS2, and a pyridoxal phosphate-dependent transferase were linked to metabolites involved in shikimate, amino acid, and proline metabolism. Collectively, these results demonstrate that salinity tolerance in rice is associated with coordinated transcriptional and metabolic reprogramming that supports oxidative stress mitigation and adaptive stress responses.
Chedid, E.; Patin, E. R.; Tran, J.; de Miguel, M.
Show abstract
Drought is a major abiotic stress threatening plant productivity and agricultural sustainability, yet the molecular mechanisms underlying adaptive root responses to water deficit in the water use strategies continuum remain insufficiently understood, particularly in perennial crops. In this study, we explored drought responses in nine accessions belonging to three wild Vitis species (V. acerifolia, V. candicans, and V. doaniana) displaying varying drought-response strategies. Plants were subjected to moderate drought stress (40% soil water content) for three weeks under greenhouse conditions. By integrating physiological, metabolic, and transcriptomic analyses, we aimed to identify both conserved and species-specific mechanisms associated with drought adaptation. Differential expression analyses revealed a conserved core set of drought-responsive genes shared among species, including genes involved in abscisic acid signaling, reactive oxygen species detoxification, solute transport, and plant defense. In parallel, each species exhibited distinct transcriptional and metabolic signatures reflecting alternative adaptive strategies related to osmoregulation, and oxidative stress mitigation. Weighted gene co-expression network analysis (WGCNA) further revealed significant associations between constitutive, non-plastic gene expression and root phenotypic traits. Overall, our findings demonstrate that wild Vitis species rely on both conserved stress-responsive pathways and species-specific constitutive regulation to cope with drought stress. These results highlight the importance of root-associated traits and intrinsic regulatory networks in shaping drought adaptation and provide new targets for the development of drought-resilient grapevine rootstocks.
Clerget, B.; Sidibe, M.; vom Brocke, K.; Raharinivo, V.; Ortiz, D.; Trouche, G.
Show abstract
Crop photoperiodism models assume that flowering time is primarily controlled by daylength, yet many field observations contradict this view. We previously proposed an alternative framework integrating daily changes in sunrise and sunset times (dSR and dSS). Variety trials in Madagascar and in Argentina supported this concept: mid-late sorghum varieties from the northern hemisphere flowered late or very late when sown in November and December, consistent with the higher dSR/dSS values of the southern hemisphere summer. One Malian variety, sown monthly over six years in West Africa, exhibited high interannual variability in flowering time when sown between November and February. This revealed that up to four photoperiodic responses -- two quantitative and two qualitative, occurring at different times of the year -- may coexist within a single late photoperiod sensitive variety. All responses use only dSR and dSS cues. The qualitative responses are triggered by an internal phasic coincidence, which is set by a linear relationship between dSR and dSS at the onset of plant photoperiod sensitivity, and between dSR+dSS at panicle initiation. The research model fitted data from 28 varieties grown in Mali well. It also accurately fitted the duration to PI observed in three varieties sown at tropical and temperate latitudes. HighlightThe seasonal photoperiodic adaptation of flowering time in sorghum plants may rely on several signal transduction pathways regulated by sunrise and sunset times rather than day length.
Loupit, G.; Sancharme, M.; Petriacq, P.; Valls Fonayet, J.; Bittebiere, A.-K.
Show abstract
Transgenerational plasticity can shape plant phenotype and influence plant response to environmental changes in interaction with the current conditions. While how past stress interact with either current optimal or stress conditions is increasingly documented within a single plant, transgenerational plasticity remains particularly poorly understood especially at the metabolome level. In our study, we investigated whether heat stress induces transgenerational metabolic and phenotypic modifications along two successive clonal ramet generations of the sub-Antarctic aquatic plant Limosella australis. We performed untargeted metabolomic approaches and measured morphologic and performance traits, to assess both transgenerational plasticity of the metabolome and the phenotype. We found that heat stress remodelled the metabolic profile and influenced the foraging strategy of our clonal plant, and that some of these metabolic changes persisted into the first clonal generation. This one therefore adopted an intermediate growth strategy, even though culture conditions were optimal. By comparing differentially accumulated features between daughter ramets from heat stressed mother ramets and from unstressed mother ramets, we identified common and specific metabolites accumulation to heat stress response, belonging to diverse compound families. However, we did not observe any adaptative advantage and any metabolic imprint during another heat stress applied on the second clonal generation. This work provides especially new clues into how plant metabolome integrates and transfers previous stressed clonal generation's information.
Chahar, N.; Pokhriyal, E.; Yadav, S.; Ren, B.; Dangwal, M.; Das, S.
Show abstract
Ovate Family Proteins (OFPs) are a class of plant-specific, negative nuclear transcriptional regulators characterized by conserved C-terminal OVATE domain. This study on comparative functional characterization of two head-to-head arranged OFPs - AtOFP2 (Ovate-OFP with full ovate domain) and AtOFP17 (Ovate-Like OFP with partial ovate domain) provides critical insight into how structural variations in ovate domain leads to functional divergence. Detailed phenotypic analysis of 28 physical and physiological traits of loss- and gain-of-function mutants revealed that both genes act as broad, pleotropic repressors of plant growth and development. Removal of repression in knock-down mutants of both genes exhibited reduced duration of seed dormancy, faster rate of germination and growth, bigger plants and significantly higher seed yield. In contrast, constitutive over-expression showed a generalized repressive nature of both genes, with nuanced differences for fine tuning of specific traits. For example, both genes showed antagonistic behaviours on root hair architecture. AtOFP2 act as a strong repressor of root hair development whereas AtOFP17 is a stronger repressor of hypocotyl and root cell architecture. AtOFP17 owing to partial ovate domain exerts a mild level of repression throughout life span as indicated by smaller plants and lesser yield in knock-down AtOFP17 mutants. On the contrary, AtOFP2 exerted a much stronger repressor effect in which > 90% over-expression mutants died at the juvenile stage ; the survival of remaining 10% is probably owing to activation of dosage-dependent feedback loop mechanism as indicated by normal growth of mature plants, and is also evident by transcriptome data. Transcriptome analysis of roots of 7-day old seedling of knock-down and over-expression mutants of AtOFP2 showed downregulation of OFP2 in over-expressed mutants. However, severely stunted phenotype indicated presence of stable OFP2 protein to exert effects. Analysis of DEGs in OFP2 mutants revealed that it acts as an important regulator working at intersection of hormonal signalling affecting critical genes required for auxin, cytokinin, GA, BR and ABA functioning. Perturbations across hormonal signalling pathways affects cell wall remodelling factors such as EXPANSINS, Xyloglucan hydrolases (XTHs) and cellulose synthases (CSLs) causing overall stunted growth; and epidermal patterning genes such as WER, GL1, EGL3, TTG1 leading to severely reduced root length and root hairs. Significantly, functional analysis of this master regulator highlighted a significant economic potential. Knockdown of both these genes relieves their natural repression on reproductive traits, leading to longer siliques, bigger and heavier seeds, and substantially increased overall seed yield, positioning AtOFP2 and AtOFP17 as highly valuable targets for agricultural crop improvement.
Shadbolt, J.; Schreiber, M.; Russell, J.; Waugh, R.; Houston, K.
Show abstract
Heavy metals act as essential metalloprotein cofactors in numerous physiological processes but can become toxic when non-essential metals accumulate or when essential metals are in excess. As plants continuously encounter heavy metals through their roots, they have evolved complex homeostatic mechanisms to regulate metal uptake and distribution. The Heavy Metal ATPase (HMA) gene family encodes a group of heavy metal transporting P-type ATPases that have been linked to stress resistance and nutrient supply. Here, we used a bioinformatics approach to identify and characterise 13 HMA genes containing characteristic P1B-type ATPase domains and motifs in the barley Morex V3 reference genome. The genes are located on five of the seven barley chromosomes. Phylogenetic analysis revealed that they cluster into five sub-clades, including one clade unique to barley. Expression profiling across multiple datasets showed distinct temporal and tissue-specific expression patterns among HvHMAs, with several members exhibiting significant transcriptional responses to specific biotic and abiotic stresses. By utilising recently available pan-transcriptomic and pan-genomic resources, we have identified substantial allelic diversity and inter-accession variation in HvHMAs. Our findings suggest that HvHMAs have functions extending beyond canonical heavy metal homeostasis and warrant further investigation for their potential roles in broader physiological and stress-related processes.
McGovern, C.; Adrio, M.; Aliki, H.; Vichos, R.; Powell, W.; Sharma, R.
Show abstract
Far-red light (FR; 700-750 nm) is increasingly incorporated into controlled-environment lighting because it can improve photosynthetic efficiency when combined with comparatively shorter wavelengths. In long-day leafy crops such as spinach, however, FR may also promote the transition from vegetative to reproductive growth and thereby reduce marketable yield. Most studies have evaluated FR fraction, intensity or end-of-day exposure, whereas the developmental timing of FR has rarely been tested, particularly in spinach. Here, we evaluated six commercial spinach cultivars (Amador, Harp, Renegade, Responder, Rubino and Santa Cruz) in an indoor vertical farm under a common red-green-blue background (PPFD 260-264 {micro}mol m-{superscript 2} s-{superscript 1}, 12 h photoperiod, 24 {degrees}C) and four FR timing treatments: no FR (Control), FR throughout production (FullFR), FR during early development only (EarlyFR), and FR during late development only (LateFR). LateFR increased marketable fresh weight relative to Control (244 vs 224 g) and reduced flowering incidence, whereas far-red supplied during early development reduced fresh weight (158 g) and increased flowering. The magnitude of the timing response differed among cultivars: switching from EarlyFR to LateFR recovered 0 % fresh weight in Amador but 107 % in Renegade and Rubino, with the largest penalties occurring in otherwise bolt-resistant cultivars. EarlyFR also increased total chlorophyll and reduced the chlorophyll a:b ratio. These results show that FR response in spinach is strongly conditioned by developmental stage and cultivar. Although LateFR received more total far-red than EarlyFR, it behaved like the Control, indicating that the penalty was set by far-red timing rather than dose. Treatment differences in bolting and yield tracked an estimated phytochrome photostationary-state deficit during early development: a phytochrome-deficit model markedly outperformed a cumulative-dose model ({Delta}AIC = 441), and the deficit x cultivar interaction was strong (p < 0.001), with bolt-resistant cultivars losing most yield when far-red coincided with the early developmental window. We therefore propose that FR should be treated as a genotype-dependent management variable rather than as a fixed spectral input, with late application and bolt-resistant cultivars offering the most favourable combination for vertical-farm spinach production. Framed within the breeders equation, the close match between the trial and production environment and the scope for shorter breeding cycles indoors suggest that genotype and far-red timing can be optimised jointly to accelerate genetic gain.
Abbasi, K.; Qayyum, H.; Naseer, S.; Sun, M.; Quraishi, M. A.; Danyal, Y.; Hao, Y.; He, Z.; Rasheed, A.
Show abstract
The availability of pangenome and resequencing of wheat collections have facilitated the discovery of gene-trait associations in wheat. Yellow stripe-like (YSL) proteins play a key role in the uptake and translocation of metals and yet have not been fully identified and analyzed at the genome-wide level in wheat. In this study, 26 TaYSL genes were identified and divided into four distinct clades, each clade sharing similar domains and motif compositions. Most genes were upregulated under iron deficiency, whereas homoeologs of TaYSL1 were downregulated. Both SNP-based and haplotype-based association studies were used to dissect the role of TaYSLs underpinning grain iron contents (GFeC) and zinc contents (GZnC) in wheat. TaYSL6-2B and TaYSL16-1A haplotypes showed strong association with GFeC, and TaYSL14-6A showed strong association with GZnC in multiple field trials. The distribution of favorable haplotypes in global wheat collection of [~]3000 accessions showed that majority of haplotypes were more prevalent in landraces and winter wheat compared to modern cultivars and spring types, indicating their potential for use in breeding. The combination of favorable haplotypes of three YSL genes associated with GFeC and GZnC were very rare, and most of the wheat accessions has single or double favorable haplotypes. These findings provide the first comprehensive characterization of the TaYSL gene family in wheat and identify significant SNPs and elite haplotypes that can be utilized for genetic improvement and biofortification.
Jiang, T.; Tanwir, S. E.; Karn, A.; Liu, F.; Huo, H.
Show abstract
Plant regeneration is a major determinant of transformation and genome-editing efficiency, yet the endogenous regulatory networks controlling regenerative competence in horticultural crops remain incompletely understood. The miR319-TCP module regulates multiple developmental processes in plants, but its function in lettuce regeneration has not been defined. Here, we performed a genome-wide analysis of the TEOSINTE BRANCHED1/CYCLOIDEA/PROLIFERATING CELL FACTOR (TCP) gene family in lettuce (Lactuca sativa). Thirty-three LsTCP genes were identified and classified into Class I/PCF, Class II/CIN, and Class II/CYC/TB1 groups. Five CIN-class genes, LsTCP2, LsTCP3, LsTCP4, LsTCP10, and LsTCP24, were predicted as high-confidence miR319 targets and supported by degradome-based cleavage evidence. MIR319-overexpression (OX319) explants showed enhanced de novo shoot regeneration, with 94.5% regeneration efficiency and 1.92 shoots per explant, whereas STTM-miR319 suppression (S319) explants showed reduced regeneration, with 28.5% regeneration efficiency and 0.36 shoots per explant. These phenotypes were associated with altered expression of several miR319-targeted CIN-TCP genes, particularly LsTCP4, LsTCP10, and LsTCP24. Disruption of LsTCP4 increased regeneration efficiency to 91.4% and shoot production to 2.05 shoots per explant, resembling the regeneration-enhancing effect of miR319 overexpression. In contrast, disruption of the non-target CIN gene LsTCP17 did not significantly affect regeneration under the tested conditions. Together, these results identify LsTCP4 as a key miR319-responsive negative regulator of de novo shoot regeneration and highlight miR319-mediated repression of LsTCP4 as a potential endogenous strategy for improving lettuce regeneration.
Sainz, M.;Filippi, C.;Pezzutto, S.;Eastman, G.;Sotelo-Silveira, J.;Borsani, O.;Sotelo-Silveira, M.
Show abstract
The TETRATRICOPEPTIDE THIOREDOXIN-LIKE (TTL) proteins are a plant-specific family proposed to function as peripheral membrane proteins that contribute to abiotic stress tolerance in Arabidopsis, likely by maintaining cell wall integrity through brassinosteroid signaling. Previously, we identified a TTL gene that was differentially regulated at the translational level in nitrogen-fixing soybean plants under water deficit (WD) conditions. This finding prompted the characterization of the soybean TTL gene family. Using the Glycine max v4.0 proteome, we identified ten TTL homologs (GmTTL1-GmTTL10), which are unevenly distributed across five chromosomes. Phylogenetic and structural analyses grouped these genes into three clades and revealed a highly conserved exon-intron organization. Likewise, GmTTL proteins display a conserved number and arrangement of TPR and TRXL motifs. To gain insights into their potential biological functions, we integrated co-expression and differential expression analyses. This approach identified a co-expression module enriched for translationally downregulated genes related to the Gene Ontology terms "cellular anatomical entity", "membrane", "cell periphery", "cell wall modification", "nitrate assimilation", and "cell wall organization or biogenesis". Protein-protein interaction network analysis of this specific subset of genes uncovered a novel GmTTL connection with two nitrate reductase enzymes in nitrogen-fixing plants subjected to WD, potentially linking the TTL gene family to new functions or roles. This study provides a framework for future functional studies of GmTTL proteins and their contribution to abiotic stress adaptation in soybean. Key MessageThis work presents the first functional characterization of TTLs proteins in legume species and highlights key processes that may link the TTL gene family to new functions or roles.
Armas, A.;Escudero, V.;Quintana, J.;Rodriguez-Simon, M.;Abreu, I.;Collantes-Garcia, J.;Gupta, B.;Ansorena, E.;Raimunda, D.;Rubio, L.;Gonzalez-Guerrero, M.
Show abstract
O_LIEngineering nitrogen fixing crops requires not only transferring the nitrogenase structural genes, but also the accessory genes to synthesize its iron-sulphur cofactors. Scaffold protein NifU is a critical element in this system as the starting point of nitrogenase cofactor assembly. NifU has been successfully produced in plants, however, its optimal production required high levels of iron in the medium. This is likely due to a faulty connection with the endogenous iron trafficking network C_LIO_LITo identify specific elements targeting iron to NifU, pull-down assays were performed to identify showing bacterioferritin A (BfrA) as a likely candidate. Co-immunopurification, mutant characterization, iron transfer assays, and co-expression in Nicotiana benthamiana assays were carried out. C_LIO_LIBfrA transfers iron to NifU through protein-protein interactions. When these two proteins were co-expressed in N. benthamiana leaves, there was an increase in NifU production. In turn, it led to doubling NifH synthesis, a nitrogenase structural protein that is also required for the synthesis of the more complex nitrogenase cofactors. C_LIO_LIOur results provide a new element towards engineering nitrogen-fixing crops. They also underscore the importance of transferring the metal delivery systems when expressing metalloproteins in heterologous systems. C_LI
Li, D.; Adeniji, L. A. J.; Meah, R. J.; Clements, C. F.
Show abstract
Artificial light at night (ALAN) can alter the movement of nocturnal pollinators such as moths, with potential consequences for pollination services. However, most studies have focused on the presence or properties of lights, while the role of spatial lighting configuration remains poorly understood. We conducted a small-scale field experiment to test how different lighting configurations affect pollination success in moth-pollinated plants, using low-intensity LED garden lights. Potted phytometer plants of three moth-pollinated species were exposed to one of three treatments: no-light control, isolated LED point lights, or 25 m linear arrays of multiple LED lights. We quantified pollination success as both the probability of seed set and reproductive output through seed and capsule production. Experimental lighting affected plant reproductive success, with light arrays increasing seed-set probability, seed and seed capsule number relative to unlit controls, whereas point lights showed no clear effect. These results provide preliminary evidence that the spatial configuration of artificial lights may influence nocturnal pollination outcomes. Future work combining phytometer assays with direct tracking of moth movement is needed to assess whether light arrays facilitate or redirect the dispersal of nocturnal pollinators.
Datta, J.; Bhowmik, S. D.; Williams, B.; Kerr, S. C.
Show abstract
In vitro regeneration of Citrus plants is a widely used method, however, induction of adventitious roots from regenerated shoots remains a major bottleneck, limiting the recovery of healthy plants for commercial production and genomic research for crop improvement. We established an in vitro regeneration system producing profuse, healthy roots for sweet orange (Citrus sinensis cv. Benyenda) by optimising combinations and concentrations of auxins. Prior to optimising the rooting media (RTMs), we obtained a shoot regeneration rate of 90.6% from sweet orange epicotyl explants using a cytokinin, 6-benzylaminopurine (BAP). Across twelve auxin-supplemented RTMs containing different concentrations of indole-3-butyric acid (IBA) and/or 1-naphthaleneacetic acid (NAA), rooting percentages ranged from 8 - 87.5%. The combination of IBA 1.0 mg L-1 and NAA 0.1 mg L-1 promoted the best overall performance, 75 {+/-} 7.2% rooting percentage with healthy, callus-free roots ([≥]5 cm in length), whereas other RTMs with other auxin combinations induced callus and limited root elongation. The best-performing SRM and RTM were subsequently used for selection and recovery of transgenic sweet orange lines carrying an empty CRISPR/Cas9 construct, resulting in an 4.8% transformation efficiency. Both transgenic and non-transgenic rooted plantlets were successfully acclimatised under glasshouse conditions with a survival rate of 90%. This enhanced regeneration system overcomes rooting bottleneck and improves plant survival,enabling faster recovery of transgenic citrus lines within four months. It supports accelerated development for commercial applications and advances in citrus genetic improvement.
CHASSAGNAUD, D.; BEZON, L.; LE JAN, I.; FICHOT, R.
Show abstract
The sequence of leaf physiological thresholds underlying plant responses to water deficit is thought to be functionally coordinated; yet, to what extent this coordination is maintained across genotypes and environments remains poorly documented at the intraspecific level. We characterized the sequence of stomatal closure, turgor loss and xylem embolism in the leaves of two genotypes of the riparian species Populus nigra (DRA-038 vs. PG-31) subjected to control, additional nitrogen or additional potassium treatments. Under control conditions, embolism measurements using the optical vulnerability method showed that DRA-038 was more vulnerable than PG-31, in agreement with measurements performed on stems with the reference Cavitron method. Stomatal closure consistently preceded xylem embolism, while bulk leaf turgor loss was typically observed once xylem embolism had already reached 50%. Hydraulic thresholds responded to treatments in a genotype-dependent manner, the intrinsically more vulnerable genotype DRA-038 being typically more plastic. However, despite variations across genotypes and treatments, the trait sequence remained tightly coordinated such that stomatal safety margins (SSMs) remained virtually null. These findings support a strong mechanistic integration of leaf hydraulic thresholds in poplar across genetic units and varying environments, questioning whether to favour intrinsic tolerance or plastic capacities in breeding future drought-tolerant genotypes.
Pepe, M.; Hesami, M.; Jones, M.
Show abstract
Applications of tissue culture are critical for Cannabis sativa L. (cannabis), supporting clonal propagation, germplasm preservation, pathogen elimination, among other biotechnological applications. However, extensive genetic diversity associated with cannabis results in highly variable responses to in vitro conditioning, and no consensus basal media formulation exists to support reproducible micropropagation across genotypes. To address these limitations, a hybridized ensemble-NSGA-II approach was employed for concurrent optimization of individual media components to create a species specific, cultivar inclusive basal salt formulation for cannabis micropropagation. The resulting PHJ media represents a unique formulation that overcomes recalcitrance across a wide array of cannabis cultivars, facilitating improved growth and uniformity for the nine cultivars used in its development and validation. These results remain consistent from explant initiation through multiple rounds of subculture. The ability of PHJ to overcome genotypic recalcitrance is telling of its potential applicability with an array of plant species beyond cannabis. Additionally, robust performance both with and without plant growth regulators underscores the plausible use of PHJ for diverse applications beyond standard micropropagation. Ultimately, this cultivar-inclusive basal medium demonstrates utility for both scientific research and industrial-scale operations.
Tsinyk, M.; Hlavackova, K.; Ovecka, M.; Rehak, J.; Sojka, J.; Spundova, M.; Kucerova, Z.; Samaj, J.; Takac, T.; Dvorak, P.
Show abstract
Copper (Cu) is an essential micronutrient whose bioavailability is strongly affected by soil physicochemical properties. During evolution, plants have developed mechanisms to flexibly adjust their metabolism to Cu status. Superoxide dismutases (SODs), including Cu/ZnSOD1 (CSD1) and FeSOD1 (FSD1), are key antioxidant enzymes regulated in Cu dependent manner in Arabidopsis thaliana. Examination of CSD1 cellular distribution and activity revealed that CSD1 is a nuclear and cytosolic SOD whose abundance and activity respond to Cu availability inversely to FSD1. Combined microscopic and biochemical analyses of Cu-dependent dynamics revealed that, unlike FSD1, CSD1 localization in guard cells (GCs) remains independent of Cu availability. CSD1 escapes miR398-mediated regulation in GCs through a cell type-specific splice variant (CSD1.2) that carries an altered miR398-binding site. In silico analyses indicate that this mechanism is also present in crop species. Functionally, the csd1 mutant showed reduced sensitivity to abscisic acid (ABA)-induced stomatal closure, a phenotype rescued by reintroducing CSD1. Biochemical and reactive oxygen species (ROS) level analyses indicate that CSD1.2 most likely acts independently of its canonical enzymatic activity in GCs and functions upstream of the ROS burst in the ABA signaling pathway. Together, we present a novel, cell-type-specific mechanism that safeguards ABA-driven stomatal closure under fluctuating Cu supply.
Nonavinakere Chandrakanth, N.; McGowan, M. T.; Gaitan, N.; Lin, F.; Ng, V.; Lipzen, A.; Singh, V.; Daum, C.; Yoshinaga, Y.; Li, S.; Su, L.; Xu, D.; Ficklin, S.; Duitama, J.; Bartley, L.
Show abstract
Elongating rice internodes present a developmental gradient from dividing meristem to mature cells, providing an elegant pseudo-time course for study of plant vegetative development. We tested the hypothesis that DNA methylation regulates gene expression during rice internode development by integrating RNA-seq and bisulfite DNA sequencing across eight internode segments. Previously described topologically associated chromatin domain borders aligned with transcription start sites of constitutive expressed genes. CpG and CHG differential methylation was enriched in young segments, consistent with maintenance methylation; whereas CHH methylation showed similar differential abundance in young and old segments. CHH and CHG methylation in upstream regions, CpG methylation within gene bodies, and any methylation in 5' and 3' untranslated regions were permissive of moderate to high gene expression. Very low expression was associated with CpG methylation upstream, CHG and CHH methylation within gene bodies, and CpG and CHG methylation downstream. A nonrandom subset of genes, including cell wall-related glycoside hydrolases, lignin and tricin biosynthesis enzymes, and WD40 proteins, showed methylation-expression correlations, with expression changes enriched in triple-marked elements. These results suggest that internode phenotypes of DNA methylation machinery mutants relate to alteration of specific target genes, opening approaches for grass culm improvement for lodging resistance and biomass production.
Amegan, K. E.; Magot, F.; Desneux, N.; Del-Valle, S.; Salgon, S.; Kergunteuil, A.; Caromel, B.; Larbat, R.; Lavoir, A.-V.
Show abstract
AbstractTomato production faces a persistent challenge from the tomato leaf miner, Phthorimaea absoluta, a pest that severely limits yields while effective resistance in cultivated varieties remains scarce. To address this gap, wild tomato relatives represent a promising reservoir of resistance traits. In this study, 24 tomato accessions, including both cultivated types and wild species, were evaluated under greenhouse (no-choice) and tunnel (choice) conditions. Resistance mechanisms were characterized through measures of antibiosis such as leaflet lesion type, proportion of attacked leaflets, and mine density. The results revealed substantial variation between and within species, allowing classification of accessions into resistant, intermediate, and susceptible groups through multivariate analysis. Notably, the wild accession Solanum habrochaites PI248707 exhibited strong resistance, in contrast to susceptible cultivated varieties such as Rose de Berne. Under choice conditions, PI248707 sustained limited damage and disrupted larval development, with early instar larvae present but few reaching advanced stages, indicating an inhibitory defense response. Untargeted metabolomic profiling further highlighted pronounced constitutive differences between wild and cultivated accessions, with S. pennellii and S. habrochaites displaying higher metabolic diversity. By integrating phenotypic and metabolic data, specific metabolite classes associated with resistance were identified. These findings underscore the potential of wild tomato germplasm in breeding programs, with PI248707 standing out as a strong candidate for resistance introgression.
Jiang, T.; Tanwir, S. E.; Zammar, S.; Bradford, K. J.; Huo, H.
Show abstract
Leaf senescence directly affects lettuce quality and postharvest shelf life, but the regulatory roles of miR319-targeted and non-target CIN-TCP transcription factors remain unclear. Here, we examined whether the miR319-TCP module controls lettuce leaf senescence through separable genetic branches. MIR319 overexpression delayed dark-induced senescence, whereas STTM-mediated miR319 suppression accelerated chlorophyll loss, photosynthetic decline, and senescence-marker activation. Disruption of the miR319-targeted gene LsTCP4 phenocopied MIR319 overexpression, supporting LsTCP4 as a pro-senescence factor downstream of miR319. We further found that the miR319 non-target CIN gene LsTCP17 also promoted senescence, as tcp17 leaves retained more chlorophyll than wild type during dark treatment. Genetic combinations showed that tcp17 enhanced chlorophyll retention in the OX319 background and partially rescued the accelerated senescence phenotype of S319, indicating that LsTCP17 acts through a route separable from the miR319-targeted branch. Together, these results reveal a split CIN-TCP architecture in which miR319-targeted LsTCP4 and non-target LsTCP17 provide parallel pro-senescence inputs, offering a genetic framework for targeted improvement of lettuce quality.
Rilwan, O.; Ibrahim, A.
Show abstract
Tomato (Solanum lycopersicum L.) is one of the most important vegetable crops in Nigeria, serving as a major source of income, nutrition, and raw material for food industries. However, its production is severely constrained by Fusarium wilt, a destructive soil-borne disease caused by Fusarium oxysporum f. sp. lycopersici. This study investigated the prevalence and severity of Fusarium wilt on tomato in Chikun Local Government Area (LGA) of Kaduna State, Nigeria. Field survey and laboratory analyses were conducted on forty-five tomato samples from three tomato farms Kujama, Kakau, and Rido. The samples were examined for disease incidence and severity. Data were analyzed using descriptive statistics and Chi-square tests. The overall disease incidence was with Rido recording the highest infection rate (80.0%), followed by Kujama (60.0%) and Kakau (40.0%). Among plant parts, the stem exhibited the highest infection frequency (80.0%), while leaves and fruits had 60.0% and 40.0% incidence respectively. Chi-square analysis indicated no significant difference (p > 0.05) in disease incidence among farms and plant parts, suggesting uniform pathogen distribution. The research recommends the adoption of integrated disease management strategies and improved farmer awareness to mitigate the impact of the disease and ensure sustainable tomato production.