Endophytic fungi form an integral part of plant microbiomes, influencing host physiology, stress resilience, and secondary metabolism. While next-generation sequencing (NGS) has greatly advanced the identification of endophytes, it often falls short of assigning functional roles, necessitating integration with culture-based approaches for downstream applications. Picrorhiza kurrooa, a critically endangered Himalayan medicinal herb valued for its hepatoprotective picrosides, suffers from reduced metabolite content in tissue culture-derived plants, likely due to microbiome loss in the course of aseptic in-vitro practices. Moreover, the diversity and functional role of fungal endomicrobiome in P. kurrooa remain unexplored. Internal transcribed spacer (ITS)-based amplicon sequencing was performed to assess and compare the endophytic fungal communities of wild-type (Wt) and in-vitro propagated (Tc) P. kurrooa. Fungal taxa unique to Wt-plants were identified and cross-referenced with culturable isolates. A dominant isolate present only in Wt-plants, Trichoderma harzianum PKRF1, was reintroduced into Tc-plants to evaluate its effect on plant growth and picroside biosynthesis. Whole-genome sequencing and comparative genomics of PKRF1 were also conducted to elucidate its functional capabilities and possible candidates for its endophytic nature. Metagenomic analysis revealed a significant reduction in fungal diversity in Tc plants, with several taxa, including Trichoderma, Cyphellophora, and Preussia, exclusively associated with Wt-plants. Inoculation of Tc-plants with PKRF1 led to successful root colonization, enhanced photosynthetic efficiency, biomass, and significantly higher levels of picrosides. Transcript profiling confirmed upregulation of key biosynthetic genes. Genomic analysis of PKRF1 revealed genes associated with multiple plant-beneficial traits, including nutrient acquisition, phytohormone production, stress tolerance, plant colonization, and competitive interactions, distinguishing it from non-endophytic Trichoderma isolates. These findings provide the first comprehensive insight into changes in endophytic fungal diversity of P. kurrooa associated with in-vitro cultivation. Furthermore, the application of cultivated endophytes from wild plants demonstrated the potential to restore microbial functions lost during in-vitro propagation and enhance secondary metabolite production in cultivated plants. Overall, this approach offers a promising strategy to integrate metagenomic information into beneficial plant-microbe interactions for practical applications.
The increasing demand for sustainable agriculture has intensified interest in beneficial microbes as eco-friendly alternatives to chemical pesticides for plant disease control. Among these, plant growth-promoting rhizobacteria (PGPR) have attracted great interest because they can suppress plant pathogens and strengthen plant health through molecular mechanisms. Recent studies suggest that PGPR protect plants from disease not only by directly attacking pathogens but also by changing how plant immune genes are expressed through epigenetic processes. This review brings together current knowledge on epigenetic regulation in plant-PGPR interactions, focusing on DNA methylation, histone modifications, and non-coding RNA pathways. PGPR colonization activates plant immune signaling through pattern recognition receptors, MAPK cascades, reactive oxygen species, and plant hormones. The review also covers the range of bacterial signals-including lipopolysaccharides, flagellin, cyclic lipopeptides, and volatile organic compounds-that prepare plant defenses, and explains how the recognition of these signals reshapes chromatin structure at defense genes. In addition, the review discusses how these changes may influence induced systemic resistance and examines emerging, though still limited, evidence on whether they could potentially be transmitted to subsequent generations. A better understanding of how microbial signals regulate host epigenetics may reveal new ways to improve plant immunity and balance growth with defense. Overall, available evidence indicates that PGPR-induced epigenetic changes represent a promising and environmentally friendly approach to crop protection; however, field-level validation and mechanistic confirmation in non-model crop species remain necessary before this strategy can be considered practically applicable.
In recent years, a deluge of big and diverse datasets from hundreds of plant species coupled with spectacular innovations in artificial intelligence (AI) and generative AI (GenAI), has altered the landscape of plant science. These developments are increasingly democratizing the field, reducing the entry barriers to complex data analysis and enabling a new wave of innovative research while introducing new challenges. Therefore, in this era, it is critical that we train the next generation of plant scientists to be AI-literate, i.e., not only proficient in using AI but also vigilant about its pitfalls and biases. In this Perspective, we call for six strategic shifts necessary for training the next generation of plant scientists. We argue that while maintaining a core focus on subject expertise, educators should simultaneously emphasize development of new AI-forward pedagogical and evaluation frameworks that reward interdisciplinary and critical thinking, human-driven knowledge synthesis, self-directed learning, and conceptual understanding of workflows. For effective critique and sound interpretations based on biological reality, plant scientists must be explicitly trained in recognizing biases underlying GenAI models. Finally, we highlight the structural barriers hindering the equitable and ethical use of GenAI, where awareness and resolution is critical for sustainable growth of the field. Through the above conceptual framework and numerous plant-science focused illustrative activities, examples, and resources meant for students and educators alike, this Perspective defines high-level emphasis areas for GenAI-enabled scientific training, aimed at creating a more effective, engaged, and adaptive community of plant scientists.
Phospholipids function as dynamic regulators of plant growth and environmental adaptation, extending well beyond their structural roles in biological membranes. This review synthesizes the phospholipid metabolic network and its regulatory functions in plant physiology. We first describe enzymatic reactions and acyl-chain remodeling in phospholipid biosynthesis, and then examine the interaction between phospholipid metabolism and auxin signaling, focusing on phosphatidic acid (PA) and phosphoinositide phosphate (PIP). These lipid molecules regulate the polarization and vesicular trafficking of PIN-FORMED proteins via endocytosis and phosphorylation-dependent mechanisms, thereby controlling auxin distribution during development and stress adaptation. Particular emphasis is placed on PA, a multifunctional signaling lipid that serves as a central molecular hub. PA coordinates hormonal, stress, and circadian signals by engaging and modulating a broad spectrum of protein targets, including kinases, phosphatases, and transcription factors. We also discuss the emerging and evolutionarily conserved functions of phospholipid signaling in cell fate determination, drawing parallels from mammalian cell reprogramming to the regulation of plant cell totipotency and root patterning. Collectively, these findings underscore the critical role of phospholipid-mediated signaling in converting metabolic and environmental cues into developmental reprogramming, providing novel theoretical and functional frameworks for future research in plant lipid biology.
Obesity is a multifactorial disease associated with a chronic imbalance between energy intake and energy consumption, as well as the ingestion of high-fat foods. It is widely reported that the Mediterranean Diet (MD), a dietary regimen rich in vegetables, fruits, fiber and complex polyunsaturated lipids, can positively act on obesity onset. These aliments contain bioactive molecules that exert beneficial effects on two traits often associated with obesity: lipid accumulation and imbalance in oxidative homeostasis. Additionally, they can act on metabolic pathways linked to obesity through the cross-kingdom activity of plant miRNAs. In this review, we provide an overview of the studies describing the anti-obesogenic effect of plant-based foods typical of the Mediterranean Diet. We describe the results of recent studies that link the effect of lipid reduction with the ingestion of bioactive molecules or plant miRNAs typical of MD foods. We also report how advances in bioinformatic analyses have elucidated the role of plant-derived miRNAs in metabolic homeostasis, revealing how the cross-kingdom interaction results in the anti-obesogenic action of the MD. These findings shed light on the molecular mechanisms through which the MD dietary pattern exerts its metabolic effects, suggesting new perspectives on MD nutrition-based strategies as novel therapeutic approaches for obesity.
When in contact with microbes or other pathogens plants develop an induced defense response. This reaction is triggered by pathogen-derived molecules that provoke the so-called microbe-associated molecular pattern (MAMP)-triggered immunity (MTI) or pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI). Recognition of a MAMP or PAMP by a pattern recognition receptor (PRR) activates rapid downstream signaling, manifested in, e.g., a rise in the cytosolic Ca2+ concentration. As a consequence, defense-related genes are expressed and antimicrobial substances are produced. There is also evidence that Ca2+-induced responses show a refractory behavior in plant cells, as the reaction to an identical stimulus applied shortly after the first one is strongly suppressed, if it can be observed at all. Subsequent elicitations over a longer period of time, on the other hand, can trigger stronger Ca2+ responses, which lead to so-called "defense priming". Although refractory behavior has been documented in various plant cell types, its underlying function and causative mechanisms remain unclear. In this review article we give an overview of the refractory machinery, including elicitors, receptors, typical Ca2+ responses, and signal transduction pathways. We shed light on possible explanatory scenarios and address open questions.
Plants face various environmental stresses and have developed sophisticated adaptive mechanisms to cope with constraints. miR858a targets transcription factor (TF) MYB111 and has proven to be a key regulator in modulating plant responses to biotic and abiotic stresses. However, its transcriptional regulation and the underlying mechanisms remain unresolved. To this end, we performed the yeast one-hybrid (Y1H) assay using the miR858a promoter against an Arabidopsis transcription factor library. In this way, we identified 32 TFs that specifically interact with the miR858a promoter. By analysing expression profiles of candidate TFs under different stress conditions, mimicked by flg22, UV-B, and co-treatment of flg22/UV-B treatments, we prioritized candidate TFs, including five flg22-responsive TFs (ERF73, bZIP63, NF-YC6, AL7, and AIN1) and one UV-B-responsive TF, MYBD. Our data show that miR858a is antagonistically regulated by distinct stress-responsive TFs and by their interplay, thus highlighting, for the first time, a crucial role of miRNAs and their expression regulation in plant responses to diverse stress factors. These findings provide deeper insights into the mechanisms by which plants adapt to changing environments and offer valuable traits and approaches for breeding crops resistant to various concurrent stress factors.
A key antiviral strategy in plants involves the sequestration of viral genomic RNA by dsRNA-binding proteins DRB2, DRB3, and DRB5 within phase-separated viral replication complexes (VRCs). While these proteins colocalize in VRC condensates to suppress viral replication, the molecular mechanisms underlying viral RNA sequestration and replication arrest in the antiviral defense pathway remain enigmatic. Here, we show that the oligomerization-prone dsRBD2 domain of DRB2/3/5 adopts a modified dsRBD fold and undergoes phase separation upon interaction with dsRNA. We find that the structural modifications lead to a unique surface charge distribution that promotes multivalent, surface-exposed interaction patches on dsRBD. These features enable concentration-dependent transient self-association in DRB2/3/5 and guide the formation of gel-like condensates in the presence of individual triggers such as dsRNA, molecular crowding, or ATP. Our study identifies a plausible mechanism of dsRNA-binding protein induced phase separation and suggests that RNA sequestration via condensate formation contributes to plant antiviral immunity.
Plant-based serine protease inhibitors represent a promising class of bioactive compounds with potential therapeutic relevance. In this study, serine protease inhibitor-enriched peptide fractions were isolated from Zingiber officinale, Allium sativum, and Momordica charantia. Fractions were enriched using ammonium sulfate precipitation, followed by ion-exchange chromatography, and characterized using preliminary physicochemical approaches, including SDS-PAGE (≈ 1-15KDa), UV-visible spectroscopy, Fourier-transform infrared analysis, and amino acid profiling. The peptide-enriched fractions exhibited moderate antibacterial activity against Escherichia coli and Bacillus thurigiensis, with MIC values in the mg/ml range, consistent with partially purified natural fractions. Antifungal activity against Aspergillus niger was observed at approximately 4 mg/mL. In a plant-based Tobacco Mosaic Virus (TMV) model using Nicotiana leaves, the peptide-enriched fractions reduced lesion development, indicating measurable antiviral activity. In this experimental system, the maximum inhibition ranged from approximately 58% to 86% depending on the assay format. Thrombolytic assays demonstrated moderate clot lysis (up to 42.95%) with low hemolytic activity under the tested conditions. Molecular docking suggested potential interactions between peptide motifs and serine protease targets, providing a basis for experimental evaluation. Consistent with this, enzyme inhibition assays demonstrated serine protease inhibitory activity, with IC50 values ranging from 0.15 nM (ASP fraction) to 24 µM (ZOP fraction). Kinetic analyses further revealed distinct modes of inhibition, including competitive, uncompetitive, and mixed mechanisms, depending on the fraction evaluated. As structural identity and purity were not confirmed using the mass spectrometry-based approaches, these findings should be interpreted as an early-stage functional assessment. Definitive structural characterization and further biological validation are necessary to clarify their mechanistic and translational relevance.
Neuroblastoma is characterized by noticeable resistance to chemotherapy, largely driven by the ability of tumour cells to reorganize stress-adaptive signalling networks rather than relying on single oncogenic drivers. We conducted a study to investigate the pharmacological mode of action of doxorubicin in modifying adaptive signalling pathways in SH-SY5Y neuroblastoma cells, and whether the capacity of plant metabolites can exploit emergent biochemical vulnerabilities. Transcriptomic profiling through RNA sequencing conducted 48 h post-doxorubicin exposure unveiled the organized disruption of pathways linked with amyloidogenic processes, oncogenic signalling pathways, oxidative stress, and DNA repair. The protein-protein interactions, coupled with Kyoto Encyclopedia of Genes and Genomes pathway evaluations, revealed five network-central-hubs: BRAF, GSK3β, PARP1, BACE1, and MAOB. Structural docking integrated with 200 ns molecular dynamics simulations illustrated binding stability across multiple targets driven by three metabolites, Lactol binding to BRAF (-54.13 kcal/mol) and MAOB (-39.08 kcal/mol), Amino(1H-indol-2-yl)acetic acid to BACE1 (-41.07 kcal/mol) and GSK3β (-47.38 kcal/mol), and Quercetin-3-(6″-malonyl-glucoside) binding to PARP1 (-46.03 kcal/mol). In vitro Cell Counting Kit-8 proliferation assays validated the significant anti-neuroblastoma efficacy, with the lowest IC50 (0.2397 µM) being exhibited by Amino(1H-indol-2-yl)acetic acid, followed by Lactol (1.226 µM) and Quercetin-3-(6″-malonyl-glucoside) (1.301 µM), which mirrored the cytotoxic action of doxorubicin (1.306 µM). These results suggest that plant-derived metabolites may interact with stress-adaptive signalling pathways connected with neuroblastoma. However, direct experimental validation of target engagement and pathway modulation will be required to confirm these predicted interactions.
Sugar crops, including but not limited to sugarcane, sugar beet, sweet sorghum and stevia, are major sources of sugar production in the world. However, conventional breeding approaches, limited by long breeding cycles, low efficiency and restricted capacity to improve complex traits in sugar crops, are increasingly insufficient to address the challenges posed by climate change and the demands of sustainable agriculture. This review systematically summarizes recent advances in biotechnology and molecular breeding that have transformed sugar crop improvement. Recently, high-throughput sequencing technologies have generated extensive multi-omics resources. Concurrently, numerous functional genes and genetic elements with substantial breeding potential have been identified and cloned, offering precise targets for the key agronomic traits in sugar crops. Marker-assisted selection has been successfully implemented to enhance disease resistance, while genomic selection has demonstrated well for the evaluation and selection of complex quantitative traits. Importantly, genetic transformation systems have enabled precise manipulation of target genes and facilitated the creation of novel germplasm. In the future, the integration of multi-omics data, artificial intelligence, high-throughput phenotyping and precision genome editing into an intelligent breeding framework will be essential for achieving breeding by design and developing climate-adaptive and smart cultivars. Ultimately, these technological innovations will expand the role of sugar crops beyond traditional sugar production, positioning them as a central platform for sustainable biomanufacturing and providing critical support for global sugar security, energy transition and the development of the bioeconomy.
Wheat dwarf virus (WDV) is an emerging constraint to cereal production whose epidemiological significance has intensified under climate change. Rising temperatures, extended vector activity, and the expansion of Psammotettix alienus into new regions have increased both the frequency and severity of WDV outbreaks. Beyond its direct effects on plant development, WDV acts as a powerful regulator of host physiology, functioning as a host signalling hub that reprograms hormonal signalling, alters source-sink relationships, disrupts redox homeostasis, and modulates responses to both abiotic and biotic stress. Recent molecular studies have revealed how viral proteins manipulate the cell cycle, transcriptional machinery, and RNA silencing pathways to optimise viral replication while attenuating defence responses. These processes intersect with core stress-response networks, particularly those governed by abscisic acid, gibberellins, cytokinins, and auxin, positioning WDV as a model system for investigating hormonal crosstalk under combined stress. Despite advances in genomics, transcriptomics, and vector biology, major knowledge gaps persist regarding WDV interactions with co-occurring fungal pathogens, its impact on the plant microbiome, and its role in shaping cereal resilience under drought, heat, or nutrient limitations. This review synthesises current understanding of WDV biology from the molecular to the ecological scale, highlights mechanisms underpinning stress integration, and outlines future research priorities essential for developing sustainable management strategies in a changing climate.
Tumor necrosis factor receptor-associated factor 6 (TRAF6) is an E3 ubiquitin ligase that plays a crucial role in inflammation, immune responses, and tumor development. It was reported that TRAF6 primarily catalyzes K63-linked polyubiquitination to stabilize substrate proteins, thereby facilitating the malignant phenotype of tumors. Beyond its cytoplasmic roles, TRAF6 undergoes nuclear translocation in response to specific stimuli, where it interacts with chromatin modifiers. TRAF6 acts as a central mediator in key signaling pathways downstream of the Toll-like receptor, interleukin-1 receptor, and tumor necrosis factor receptor superfamilies, including NF-κB activation. TRAF6 exerts diverse oncogenic functions, including promoting cell proliferation, migration, metastasis, immune evasion, and therapy resistance. This involves modulating cellular pathways such as NF-κB and MAPK signaling, which contribute to malignant progression. Aberrant TRAF6 activation contributes to the pathogenesis of multiple malignancies, including colorectal cancer, melanoma, hepatocellular carcinoma, and acute myeloid leukemia, making it a promising therapeutic target for cancer treatment. This review summarizes the structural features, substrate diversity, and multifaceted roles of TRAF6 in cancer, as well as the development of TRAF6-targeting drugs and strategies. We hope this review can provide a comprehensive perspective on TRAF6-targeted therapeutic strategies for cancer.
E3 ubiquitin ligases play crucial roles in plant growth and development, as well as in responses to various stresses. However, the specific regulatory mechanisms of E3 ligases under heat stress remain largely unexplored. In this study, we investigated two homologous E3 ubiquitin ligases, SlXERICO1 and SlXERICO3 (SlXERICO1/3), which were significantly responsive to heat stress in tomato (Solanum lycopersicum L.). Our results showed that the slxerico1 and slxerico3 mutants had lower heat tolerance compared with wild-type plants. A yeast two-hybrid screen identified the heat shock factor (Hsf) transcription factor SlHsfB3b as interacting with SlXERICO1/3. We found that SlHsfB3b was degraded via SlXERICO1/3-mediated ubiquitination under heat stress, negatively regulating tomato thermotolerance. Interestingly, SlHsfB3b specifically interacted with the HsfA subfamily member SlHsfA6a, which positively regulates thermotolerance by transcriptionally activating the expression of SlHsfA2, SlHSP17.6A, and SlHSP70-18. Furthermore, SlHsfB3b interfered with the transcriptional activity of SlHsfA6a. The heat-sensitive phenotypes observed in slhsfa6a slhsfb3b double and slhsfa6a single mutant plants revealed that SlHsfA6a functions downstream of SlHsfB3b in regulating heat tolerance in tomato plants. Taken together, the current findings provide evidence that SlXERICO1/3 enhances thermotolerance in tomato by modulating the SlHsfB3b-SlHsfA6a molecular module.
Salinity stress is one of the major obstacles to glycophytic crop production worldwide, including rice. It alters cellular metabolism, causing significant crop destruction that results in substantial reductions in yield. The overexpression of C4 enzymes, such as phosphoenolpyruvate carboxykinase (PEPCK), at high levels in C3 transgenic plants through genetic engineering can decrease oxidative stress while increasing photosynthetic capabilities. In this research, we evaluate the efficiency of transgenic rice plants (Oryza sativa L. cv. IR64) overexpressing PEPCK genes in mitigating salinity stress and increasing photosynthetic efficiency. The T1 transgenics showed increased levels of several biochemical factors, including ascorbate peroxidase (APX), catalase (CAT), proline, glutathione reductase (GR), and guaiacol peroxidase (GPX) activities. This was accompanied by reduced levels of malondialdehyde (MDA), hydrogen peroxide (H2O2), and electrolytic leakage, suggesting an effective antioxidant defense mechanism against the oxidative damage driven by salt stress. Photosynthetic parameters-such as chlorophyll content, net photosynthetic rate, intercellular CO2 content, and stomatal conductance-were elevated in transgenic plants compared to control plants. The transgenics also exhibited superior agronomic characteristics. Our findings provide conclusive evidence of the PEPCK gene's potential role in regulating salt stress response and tolerance in rice plants.
The greatest cause of death from breast cancer is metastasis, yet little is known about the molecular mechanisms behind this phenomenon. Using four publically accessible datasets, we conducted a thorough transcriptome analysis of 187 samples from seven breast cancer metastatic sites: the brain, bone, lung, liver, lymph nodes, skin, and local-regional skin (skinlr). Of the 12,005 genes that were found to be shared by all samples in this investigation, 604-885 differentially expressed genes (DEGs) were unique to each metastatic location. Pathways including PI3K-Akt signaling, prolactin signaling, complement, and coagulation cascades were identified by functional enrichment analysis as important metastasis drivers with unique functions in different locales. The results of regulatory analysis revealed 77 upstream factors, including 14 kinases (like EPHB3, PAK3) and 63 transcription factors (like ESR1, FOXA1, and GATA3), some of which were discovered for the first time in breast cancer metastases (like TCF4, HOXA10). It was shown that hub genes including MMP9, SPP1, and PDGFRB are essential for the survival and development of metastases, offering new information on site-specific biology. Crucially, by identifying site-specific molecular markers, these discoveries pave the way for personalized medicine techniques and allow tumor-specific therapy tactics, such as targeting Central Carbon Metabolism in lung and skin metastases. This work provides actionable options for tumor-specific treatment and tailored interventions by highlighting new molecular candidates and signaling pathways for metastatic breast cancer.
The heat shock transcription factor (HSF) family is a core regulatory component for plants in response to adversity stress and plays a pivotal role in regulating plant reactions to abiotic stress. Lanzhou lily (Lilium davidii var. unicolor) is an economically and horticulturally important bulbous crop widely cultivated in Northwest China, and its growth and yield are severely threatened by high-temperature stress during the growing season. Although HSF genes have been extensively and thoroughly investigated in other plant species, their functional characterization in lilies remains elusive. In this study, a total of 41 LdHSF genes were identified from the genome of Lilium davidii var. unicolor using bioinformatics approaches. The proteins encoded by these genes exhibited considerable variations in the number of amino acids (aa), as well as distinct isoelectric points (pI) and instability indices. Phylogenetic analysis classified these 41 LdHSF genes into three subfamilies (A, B and C). Promoter analysis revealed that the promoters of most LdHSF genes were rich in light-responsive cis-elements. Meanwhile, the promoters of some genes were highly abundant in hormone-responsive cis-elements, whereas those of other genes were enriched in stress-responsive cis-elements. Gene expression heatmaps and transcriptomic data demonstrated that the expression patterns of LdHSF genes showed significant differences in various tissues and under heat treatment. Based on transcriptomic and RT-qPCR data, we further screened out LdHSF10 and LdHSF40 as the major genes responding to heat stress. Functional experiments verified that these two genes encoded nuclear-localized proteins with transcriptional activity. Collectively, these findings lay a solid foundation for elucidating the molecular mechanisms underlying the regulation of heat tolerance by HSF transcription factors (TFs) in lilies in future research.
Abscisic acid (ABA) receptors (PYL) play a pivotal role in plant responses to abiotic stress. However, functional characterization of PYL genes in sugar beet response to stresses remains unexplored. Here, 11 BvPYL genes were identified in the sugar beet genome, and they were classified into three subgroups. A comprehensive analysis of their gene structures, sequence features, chromosomal distributions, and promoter cis-elements was conducted. Furthermore, their evolutionary relationships, predicted interaction networks, and expression patterns under drought stress were investigated. qRT-PCR and transcriptomics data revealed expression profiles of the BvPYL family from two perspectives: short-term response and long-term adaptation to drought. Most BvPYL members were up-regulated under both conditions. Subcellular localization analysis showed that BvPYL8 is nuclear-localized. Protein interaction screening and molecular docking predicted that BvPYL8 interacts with multiple PP2C proteins (e.g., PP2C8, PP2C24, PP2C37, PP2C50, PP2C51 and PP2C56) through hydrogen bonding with a key asparagine residue (ASN-148), and their interaction was experimentally verified using the Y2H and BiFC assay. A molecular mechanism for the BvPYL8-PP2Cs-BvSnRK2s-TFs pathway in the ABA signaling pathway under drought stress was proposed. These results may serve as a springboard for further functional exploration of the BvPYL gene family in sugar beet and its related species, and provide important target genes for improving crop drought tolerance through genetic engineering and molecular breeding.
The lack of the literature data on the actual CO2 assimilation and dissimilation in aquatic plants under conditions of high chromium concentrations prompted this study to determine the efficiency of the photosynthetic apparatus and the actual rates of photosynthesis and respiration in Callitriche cophocarpa plants under chromium stress conditions. We hypothesized that C. cophocarpa would need to display an efficient acclimation mechanism that allows for efficient carboxylation and dark respiration in the presence of Cr(VI) ions. Shoots of C. cophocarpa plants were cultured in the control medium (Cr-free) and in the medium with addition of 0.1 mM potassium chromate. Results revealed that young and mature organs of examined plants respond differently to Cr(VI) ions. In young leaves, the decrease in pigment content (in comparison to control, car, chl a, total chl, and chl b by 15, 38, 39, and 49%, respectively) and distorted chloroplast ultrastructure led to lower efficiency of photosynthesis (by 22.5% compared to control). These leaves also exhibited reduced dark respiration efficiency (by 36.2% compared to control). In turn, mature leaves exhibited no change in photosynthesis and respiration efficiency. C. cophocarpa withstands Cr toxicity due to acclimation strategies associated with the reduction in the size of photosynthetic antennas and the effective use of reduced amounts of incoming radiation, as well as efficient dark respiration in mature leaves.
Plants adapt to abiotic stresses by a variety of physiological and molecular mechanisms, among which the root plays important roles via responding to underground and soilborne signals. Fructan is a polysaccharide involved in energy metabolism and stress adaptation. Orobanche cumana is a holo-parasitic plant that mainly attaches to the root of the host sunflower (Helianthus annuus). Oc6-FEH, a fructan 6-exohydrolase from O. cumana, is involved in both fructan metabolism and flooding responses. Expression of Oc6-FEH is induced by flooding and indole-3-acetic acid (IAA). Oc6-FEH possesses fructan catabolism activity and is associated with fructose release. Overexpression of Oc6-FEH in the host sunflower reduces malondialdehyde (MDA) and hydrogen peroxide (H2O2) accumulation, boosts the activities of antioxidant enzymes, including peroxidase (POD) and superoxide dismutase (SOD), and enhances photosynthetic performance. The expression level of Oc6-FEH was found to be positively associated with the flooding tolerance of invading O. cumana, which is connected to the host root. Furthermore, IAA treatment also improved the flooding tolerance of O. cumana. In summary, the metabolism of fructan and the activity of Oc6-FEH were demonstrated to ameliorate waterlogging stress. Oc6-FEH provides a promising genetic target for the improvement of flooding tolerance in crops.