Physiologia Plantarum

O_LIC4 photosynthesis and the crassulacean acid metabolism (CAM) rarely co-evolved in a single lineage, but Portulaca can switch from C4 to CAM under drought stress. Little is known about CAM responses to nutrient availability, hence the goal of this work was to assess the influence of macronutrients over C4-CAM. C_LIO_LIP. oleracea was grown hydroponically and subjected to treatments (+/- PEG) for: nitrate deficiency (-NO3-), ammonium (NH4+), NO3- + NH4+, magnesium (-Mg), phosphorus (-P), calcium (-Ca), potassium (-K), and sulphur (-S) deficiencies, and salt stress. Samples were monitored for diurnal titratable acidity ({Delta}H+), osmotic potential, and gene relative expression for core C4/CAM and signaling genes. C_LIO_LI-NO3- induced CAM even without PEG, a process probably without the mediation of abscisic acid (ABA). Notably, -P showed a trend to induce CAM without PEG and -Ca prevented CAM induction even with PEG. Salt stress induced CAM, and NH4+ was not toxic for P. oleracea. Other treatments showed less conspicuous responses. C_LIO_LIThis work brings an unprecedented overview of the nutrition of C4 and CAM, suggesting perspectives for deepening the study of C4-CAM. Understanding the molecular mechanisms and environmental signaling of C4-CAM is essential for realizing the evolution of two CCMs in a single plant. C_LI

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.

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.

The glandular trichomes in Cannabis sativa, found predominantly on female flowers, produce and store a variety of unique phytocannabinoids, increasingly studied for their use in medicinal applications. Maximizing yield and cannabinoid profiles requires the optimization of the environmental factors that regulate plant growth. Light plays a prominent role, both as an energy source but also as an important developmental signal. Thus, optimization of lighting strategies, particularly through customizable light-emitting diode (LED) fixtures, has become a major focus of controlled-environment cannabis research. Here, we focus on the effect of blue-enriched and far red-enriched light spectra on the morphological traits and biochemical profiles of two THCA-dominant varieties: Pineapple Cough and Rocky Fire #7. Spectral composition exerts modest and genotype-specific effects on the plant development, inflorescence biomass, and cannabinoid concentration but we demonstrate a positive correlation between total yield and plant height in both varieties, regardless of spectra. We also show that growth under far-red enriched light affects the visible pigmentation in both varieties with significantly lower chlorophyll levels and paler fan and sugar leaves. Finally, we demonstrate that far-red light consistently increased the trichome stalk length in both varieties, suggesting that spectral composition can alter trichome development and morphology. Our data offers insights into cannabis development and secondary chemical profiles in response to different light spectra, allowing growers to adjust light spectra to obtain desirable cannabis traits for industrial production.

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.

Chickpea (Cicer arietinum) is a globally important legume crop whose productivity is frequently constrained by terminal drought, particularly in rainfed systems. We used high-throughput phenotyping of 35 diverse chickpea haplotypes at contrasting watering regimes (80% and 40% field capacity) to identify superior haplotypes. Significant haplotype:watering interactions were observed for water-use dynamics, growth rates, biomass accumulation and nodulation, indicating strong genetic control over drought responses. Certain haplotypes (e.g., ICC2210 and ICC18839) maintained relatively high water-use efficiency and growth under stress, while others exhibited pronounced reductions in biomass and nodulation. Principal Component Analyses (PCA) were used to identify haplotypes associated with tolerant and sensitive stress phenotypes. Metabolomic profiling revealed widespread reprogramming of metabolism under water limitation, with 57 of 82 metabolites significantly affected by treatment. A consistent decrease in tricarboxylic acid intermediates, including succinic acid, indicated altered energy metabolism, while accumulation of osmoprotectants such as proline and sucrose reflected adaptive responses to osmotic stress. Multivariate and ANOVA Simultaneous Component Analyses (ASCA) identified key metabolites as major contributors to haplotype-specific drought responses. These metabolites are linked to nitrogen metabolism, stress signalling and cellular protection mechanisms. These results demonstrate substantial variation in drought adaptation among chickpea haplotypes and confirm that the integration of phenotypic and metabolomic traits is a powerful approach to identify drought-resilient genotypes.

Several tomato (Solanum lycopersicum) varieties are sensitive to heat stress, which compromises plant growth, development, and ultimately yield. Biostimulants represent a promising approach to improve crop performance, yet their widespread adoption is hindered by the incomplete understanding of their mechanisms of action. This study aimed to elucidate the physiological and molecular effects of a protein hydrolysate-based biostimulant (Leafamine(R)), in tomato, under both optimal and heat stress conditions. Leafamine(R) increased primary root length by 15 to 20% compared to the controls, independent of the tested conditions, through promotion of cell division and potentially expansion. Transcriptomic analyses revealed the upregulation of genes involved in cell division and expansion under both optimal and heat stress conditions and the downregulation of heat stress markers under heat stress conditions. Hormone and metabolite profiling showed elevated levels of jasmonic and salicylic acid, putrescine, citrulline, and GABA, after Leafamine(R) treatment, consistent with the activation of stress tolerance pathways. Leafamine(R) pre-treated seedlings exhibited reduced growth inhibition during heat exposure, suggesting a priming effect. These findings highlight Leafamine(R) as a promising biostimulant for enhancing tomato growth in the context of climate change and the potential of biostimulants generically.

Chitooligomers can act as plant biostimulants or biopesticides, but todays chitosan-based agro-biologics often lack sufficient efficacy. This is due to a lack of scalable production processes for structurally well-controlled chitosans combined with a limited understanding of structure-function relationships. Chitosans differ in their degree of polymerization (DP), fraction and pattern of acetylation (FA and PA). While the influence of DP and FA on antimicrobial and phytostimulatory properties is at least partially known, this is not yet the case for PA. PA can be partially controlled by using enzymatic rather than acid hydrolysis for oligomer production. We have used recombinant chitinases and chitosanases to hydrolyse a well-characterised chitosan polymer, and purified oligomers with different DP. We have structurally characterised the products and tested their abilities to protect tobacco from viral disease. Chitinase products were dominated by GlcNAc units at their reducing and non-reducing ends, with GlcN units dominating their centers, and v.v. for chitosanase products. While the chitinase-derived hydrolysates were inactive, the chitosanase-derived oligomers possessed elicitor and priming activities and protected plants from disease, and their activity increased with increasing DP. Clearly, the Bacillus chitosanase used is well-suited to set up a scalable production process for chitosan oligomers with promising agro-biologic properties. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=95 SRC="FIGDIR/small/731087v1_ufig1.gif" ALT="Figure 1"> View larger version (56K): org.highwire.dtl.DTLVardef@c312e9org.highwire.dtl.DTLVardef@10eaf99org.highwire.dtl.DTLVardef@12a937corg.highwire.dtl.DTLVardef@38dc8c_HPS_FORMAT_FIGEXP M_FIG C_FIG

ContextUnderstanding how and when environmental conditions influence overall crop performance is crucial for optimising the development of genotypes to a specific breeding target environment. We focused on economically important traits of Australian rain-grown cotton including fibre yield and quality traits, which have not been investigated comprehensively. The aim of the study was to identify relevant environmental factors, and the timing and extent of their impact on rain-grown cotton production. MethodsWe used a data driven approach to analyse the relationship between ten climate related environmental factors across various plant growth stages and eight fibre yield and quality traits, using a large-scale field dataset of 9,283 records collected over 23 years at 4 locations, with 53 unique year-location combinations. We applied eight complementary statistical models including stepwise, penalised and Bayesian linear regression, regression-tree based ensemble methods and deep learning frameworks to (1) select the most essential environmental covariates affecting rain-grown cotton production, and (2) evaluate the predictive performance of these models. ResultsThe environmental impacts on rain-grown cotton production were trait and growth-stage specific. Number of rainy days and solar radiation were identified as the most influential environmental factors for fibre yield traits, vapour pressure deficit at maximum daily temperature was the most influential factor for majority of fibre quality traits. However, each analysed trait was influenced by multiple environmental factors across multiple growth stages (rather than a single factor or a single growth stage). These influential covariates explained a wide range of variation in the traits, accounting for 5.8% to 68.2%. Using the best-fit random forest model, our findings revealed non-linear relationships between key environmental covariates and the traits. ConclusionsEnvironmental factors at different rain-grown cotton growth stages are key determinants for the performance of end-of-season fibre yield and fibre quality parameters. These findings highlight the need to account for environment conditions when developing cotton varieties optimised for rain-grown production systems. Potential strategies are proposed whereby these key environmental factors can be used to increase the rate of genetic gain in rain-grown cotton production systems. ImplicationsThe results of this study will be crucial for future genetic evaluations and analyses of genotype-by-environment interaction effects in rain-grown cotton, which must account for the influence of the environment on plant performance. Furthermore, these methods can be applied to other species to identify critical growth stages and environmental factors which most influence crop performance.

Horseweed (Erigeron canadensis) is a widely distributed annual weed that can cause significant yield losses if not properly controlled. Its phenotypic plasticity allows it to rapidly acclimate to new environmental conditions, such as drought and herbicides, such as glyphosate, with the potential for cross stress acclimatization. The objectives of this research were to uncover the physiological and genetic effects at the intersection of drought stress and glyphosate resistance. To this end, we performed greenhouse dose response experiments, RNAseq, 14C glyphosate absorption and translocation, and cuticular lipid profiling via GC/MS. Greenhouse dose-response experiments revealed that, after drought stress, there was a 2.5-3.7 fold reduction in glyphosate sensitivity via a significant reduction in glyphosate absorption, regardless if the starting population was resistant or susceptible to the field use rate already. Cuticular waxes were collected from each population with and without drought stress and were analyzed via GC/MS. When comparing total wax loads of plants grown under WW and DS conditions, we found that drought stress significantly increased total wax loads for all three populations. Additionally drought stress substantial increases the proportion of triterpenoids in the cuticle. By RNAseq, we found serval triterpenoid biosynthesis genes upregulated after drought, which likely drive the changes in cuticle composition and ultimately increased glyphosate resistance following drought. Ultimately, understanding how drought impacts glyphosate resistance is critical for maintaining optimal weed control in the changing climate. HighlightDrought stress induces changes to cuticle composition and gene expression that reduce glyphosate absorption, thereby increasing horseweeds ability to survive glyphosate application.

The xerophyte argan (Sideroxylon spinosum) has great ecological and socioeconomic importance for Morocco. However, it is endangered due to climate change and human overexploitation. We assess drought resistance traits of argan and test the potential of arbuscular mycorrhizal (AM) symbiosis to promote its growth and mitigate the consequences of drought. We compare ten endemic Moroccan mycorrhizal inocula with the model AM fungus Rhizophagus irregularis and with the drought-adapted isolate Diversispora omaniana. We integrated physiological phenotyping and RNA sequencing to investigate the stress resistance mechanisms of argan against drought. We show that AM symbiosis significantly mitigates drought effects on plant growth, mainly by improving water relations and photosynthetic efficiency, resulting in increased growth rates. Taken together, physiological and transcriptomic analyses show that stress markers were moderatly induced during severe drought stress irrespective of mycorrhizal status, suggesting that argan adopts a drought-coping strategy that involves both, stress avoidance and stress tolerance. Argan is highly AM-responsive, both at the phenotypic and transcriptomic level, suggesting that AM has great potential to promote argan growth under drought stress.

As extreme heat events increase in frequency and intensity worldwide, understanding how woody perennial crops respond to higher maximum temperatures is critical. Perennials face distinct challenges, persisting across many seasons under increasingly variable and extreme conditions, and heat waves threaten the viability of wine grape cultivars through impacts on yield, wine quality, and long-term vine health. To test whether irrigation practices before and during heat waves affect grapevine carbon (C) storage and health, we experimentally manipulated irrigation regimes surrounding heat waves from 2019-2021 in a commercial Cabernet Sauvignon vineyard in the Lodi AVA of Californias Central Valley. Vine physiological traits and yield were measured throughout, and whole-vine nonstructural carbohydrate (NSC) concentrations were quantified after three growing seasons. Although lower supplemental irrigation reduced photosynthesis, stomatal conductance, and fruit yield, whole-vine NSCs did not differ significantly in any perennial organ by the experiments end, indicating that reproductive output and final NSC status responded to irrigation on different timescales. These results suggest that moderate supplemental irrigation during heat events is sufficient to mitigate negative impacts on yield and quality while supporting recovery of NSC reserves, though longer-term monitoring is needed to confirm that this short-term resilience persists.

Biotechnological applications of oxygenic photosynthetic organisms depend on conversion of light energy into chemical energy through photosystems (PS). This energy can then be used to drive engineered metabolic pathways that are designed as strong electron sinks. For optimal performance, the engineered host metabolism must also be balanced with the native photoprotective electron transfer network. This includes the energy-consuming function of flavodiiron (Flv) proteins, which are universal to cyanobacteria and all other oxygenic photosynthetic organisms except angiosperms. In the cyanobacterium Synechocystis sp. PCC 6803, four different Flv proteins have been shown to function in a Mehler-like reaction within two heterodimeric forms (Flv1/Flv3 and Flv2/Flv4), donating electrons to O2 without generating oxidative stress. Previously, deleting Flv3 in the Synechocystis sucrose-producing (S02) strain was shown to cause drastic metabolic changes in S02{Delta}flv3, shifting it from photoautotrophic to mixotrophic growth (Muth-Pawlak, et al., 2024). In this study, we took an opposite approach by complementing S02 with Flv3 overexpression at different levels using RBS tuning. Interestingly, this resulted in S02oeFlv3 strains with significantly increased overall photosynthetic activity and sucrose production, enhanced cell growth, and storage compound accumulation. However, these outcomes are shown not to be due to conventional O2 photoreduction activity catalysed by Flv1/Flv3. Instead, we postulate that the observed changes are linked to the previously unidentified function of homomeric Flv3/Flv3 and the strongly increased sulphate redox metabolism. Based on extensive proteomic and metabolite analyses, we hypothesise that the Flv3 homooligomer uses sulfate metabolites directly or indirectly as the final electron acceptor instead of O2. This would also explain the upregulation of sulfate-related enzymes, as well as SQR, which passes the electrons back to the PQ pool in the Flv3 overexpression strain.

Salinity is a major abiotic stress that severely limits plant growth and productivity, causing substantial yield losses. Despite barleys relative tolerance to salinity, the underlying physiological and molecular mechanisms remain incompletely understood. In this study, we employed an integrative approach combining agronomic, physiological, biochemical, and transcriptomic analyses to investigate salinity responses in the spring barley cultivar Giza 134 under both field and lysimeter-based conditions. Salinity stress significantly reduced growth and yield-related traits, with more pronounced effects observed under lysimeter-imposed salinity, reflecting higher stress intensity. These reductions were associated with impaired water status, altered leaf structural traits, and declines in photosynthetic pigment content. In contrast, proline accumulation increased, indicating activation of osmotic adjustment mechanisms. Salinity also disrupted ionic homeostasis, as evidenced by elevated Na+ levels, reduced K+ content, and an increased Na+/K+ ratio. Enhanced lipid peroxidation and elevated catalase and peroxidase activities suggested increased oxidative stress and activation of antioxidant defenses. Transcriptome profiling identified 4,298 differentially expressed genes, including 1,764 upregulated and 2,534 downregulated genes. Functional enrichment analyses revealed upregulation of pathways related to stress adaptation, redox regulation, and metabolic reprogramming, while genes associated with photosynthesis, ribosome biogenesis, and protein synthesis were strongly suppressed. Several novel stress-responsive genes involved in signaling, osmoprotection, antioxidant defense, and central metabolism were highly induced, supported by coordinated enrichment of cis-regulatory motifs in their promoter regions. Together, these findings provide a comprehensive physiological and molecular framework for salinity tolerance in Giza 134 and highlight candidate genes and pathways for breeding salt-resilient cultivars suited to saline-prone environments.

Tomato production, yield and fruit quality face major challenges due to several factors, including the complex polygenic inheritance of agronomically relevant traits, biotic and abiotic stresses, and increasingly stringent regulations limiting the use of phytosanitary products. In this context, bioinoculants have emerged as a sustainable strategy capable of enhancing yield without compromising fruit quality, conferring protection against different stresses and exerting a minimal or no impact on environment and human health. In this study, we evaluated the effects and the underlying mechanisms by which Streptomyces sp. N2A, an actinobacteria isolated from soybean rhizosphere, promotes seed germination, vegetative growth and yield in tomato, without modifying fruit quality. The obtained results demonstrated that the bacterial treatment significantly improved seedlin[g]s emergence and growth and development in vegetative stage. At harvest, yield was also significantly enhanced, mainly driven by increased individual fruit weight, which was positively correlated with a thicker pericarp in fruits from N2A-treated plants. Transcriptional analysis during fruit development revealed a coordinated induction of auxin and cytokinin signaling pathways before and after anthesis, providing a hormonal framework that underlies the promotion of pericarp growth. This study provides evidence of the beneficial effect of inoculation with Streptomyces sp. N2A on tomato yield and constitutes the first report describing the modification of fruit morphology and expression of genes involved in phytohormonal modulation during early growth and development, induced by a plant growth-promoting Streptomyces.

Acetic acid (AA), a volatile compound present in diverse microbial-derived biostimulants, enhances drought tolerance in plants. In Arabidopsis, soil-applied AA action has been linked to histone H4 acetylation and activation of jasmonate (JA) signalling. However, the mechanisms underlying AA action in crops of agronomic interest remain poorly understood. Here, we used an integrative approach to evaluate the effects of soil-applied AA on fruit yield, physiological performance, and leaf transcriptomic and proteomic profiles of tomato plants grown under optimal and suboptimal irrigation conditions (OIC and SOIC, respectively). While AA had little effect under OIC, it significantly enhanced fruit yield and photosynthesis under SOIC. Long-term water deficit triggered extensive transcriptomic and proteomic reprogramming, particularly affecting photosynthesis, RNA processing, protein biosynthesis-, modification- and homeostasis-related processes. Under SOIC, AA induced marked molecular changes that were not consistent with activation of canonical JA signaling pathways. Notably, only [~] 10% of the drought- or AA-responsive proteins were associated with corresponding transcript changes, highlighting a predominant role of regulatory layers beyond the transcriptional control to both long-term water deficit- and AA-induced protein remodeling. Strikingly, AA attenuated 47% and 35% of the transcriptomic and proteomic alterations induced by long-term water deficit, respectively. In addition, AA altered the abundance of numerous proteins that do not respond to drought, particularly ribosomal proteins and proteins involved in RNA processing. Collectively, our findings indicate that AA enhances tolerance to prolonged water deficit in tomato through mechanisms largely independent of canonical JA signaling and involving extensive downstream regulatory processes that partially mitigate stress-induced molecular reprogramming.

BackgroundSorbus sibirica Dong Hong is a promising ornamental cultivar, but its optimal light conditions remain unclear. AimsThis study evaluated the effects of shading on seedling growth, physiology, root morphology, and leaf surface micromorphology. MethodsOne-year-old seedlings were grown under full sunlight (CK) and 30%, 50%, or 70% shade for 100 days. Growth, biomass, root traits, chlorophyll, invertase, soluble protein, stomatal characteristics, and epicuticular wax morphology were determined. ResultsShading significantly affected all measured traits. The 30% shade treatment produced the greatest seedling height, which increased by 118.18% compared with CK, and the highest chlorophyll content, which increased by 120.21%. Soluble protein content was slightly increased, whereas invertase activity decreased under moderate shading. Although total biomass decreased by 18.63%, root development remained relatively stable under 30% shade, with slight increases in total root length and average root diameter. Stomatal density was highest under this treatment, and the epicuticular wax structure remained relatively regular. In contrast, 70% shade markedly inhibited biomass accumulation and root development. ConclusionsModerate shading, particularly 30%, provided the most favorable light environment for Sorbus sibirica Dong Hong seedlings and is recommended for summer nursery cultivation in Northeast China.

Plants produce a variety of O-prenylated aromatics that exhibit biological activities beneficial to human health, and the presence of the O-prenyl moiety is often crucial to their functions. However, most aromatic O-prenylation genes remain unknown in plants. In this study, we report the molecular identification of an aromatic O-prenyltransferase (PT) involved in the biosynthesis of auraptene (7-geranyloxycoumarin), a citrus metabolite known for its preservative effect on human cognitive function. Based on in silico screening focusing on the membrane-bound PT family, CpPT4 was isolated as a candidate from grapefruit (Citrus x paradisi), an auraptene-rich species. Enzymatic characterization demonstrated that recombinant CpPT4 specifically catalyzes umbelliferone 7-O-geranyltransferase activity to form auraptene, which differs from the enzymatic functions of known O-PTs. This enzyme also catalyzed aromatic N-prenylation to produce a new-to-nature auraptene analog. Regarding organ- and organellar-specific localization, it is strongly suggested that CpPT4 functions in the outer pericarp plastids, where auraptene is expected be formed. Furthermore, we found that CpPT4 orthologs are widely distributed in citrus genomes. Intriguingly, mandarins and their descendant species possess dysfunctional orthologs, which is consistent with the low accumulation of auraptene and its downstream metabolites in these species. This study provides an example of the contribution of the UbiA superfamily to O-prenylated aromatic biosynthesis. Moreover, CpPT4 can be useful as a tool in the synthetic biology-based production of auraptene and its analogs, as well as a molecular marker in the breeding of auraptene-rich citrus varieties.

Cotton (Gossypium hirsutum) is an economically important crop, but it faces increasing pest outbreaks, especially in non-irrigated areas. In this study, 20 cotton farms using center-pivot irrigation were sampled in southern Georgia to assess chemical differences between non-irrigated and irrigated areas. Proton (1H) nuclear magnetic resonance (NMR) data were obtained from cotton leaves, and Principal Component Analysis (PCA) was performed to assess differences in chemical composition. Across all samples, farm site accounted for most of the variability, but within each farm site, the PCA scores plots showed clear separation between non-irrigated and irrigated conditions in 10 sites. Inspecting the PCA loadings revealed significant resonances resembling a lipid-like signal. After reverse-phase fractionation, we observed that many of these resonances appeared together in later fractions, suggesting a lipid, specifically a fatty acid such as linoleic acid. We hypothesized that differences in net lipid saturation level may drive separation between non-irrigated and irrigated samples. Six farm sites had a significantly or marginally significantly higher degree of unsaturation in irrigated samples, while one farm site had significantly higher unsaturation in non-irrigated samples. Our results indicate that drought stress likely affects lipid profile composition, which could be driving higher herbivorous pest densities in drought-stressed crops.

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.