Plant Unsaturated Fatty Acids: Multiple Roles in Stress Response

Strategies of plants to overcome abiotic and biotic stresses

In their environment, plants are exposed to a multitude of abiotic and biotic stresses that differ in intensity, duration and severity. As sessile organisms, they cannot escape these stresses, but instead have developed strategies to overcome them or to compensate for the consequences of stress exposure. Defence can take place at different levels and the mechanisms involved are thought to differ in efficiency across these levels. To minimise metabolic constraints and to reduce the costs of stress defence, plants prioritise first-line defence strategies in the apoplastic space, involving ascorbate, defensins and small peptides, as well as secondary metabolites, before cellular processes are affected. In addition, a large number of different symplastic mechanisms also provide efficient stress defence, including chemical antioxidants, antioxidative enzymes, secondary metabolites, defensins and other peptides as well as proteins. At both the symplastic and the apoplastic level of stress defence and compensation, a number of specialised transporters are thought to be involved in exchange across membranes that still have not been identified, and information on the regeneration of different defence compounds remains ambiguous. In addition, strategies to overcome and compensate for stress exposure operate not only at the cellular, but also at the organ and whole-plant levels, including stomatal regulation, and hypersensitive and systemic responses to prevent or reduce the spread of stress impacts within the plant. Defence can also take place at the ecosystem level by root exudation of signalling molecules and the emission of volatile organic compounds, either directly or indirectly into the rhizosphere and/or the aboveground atmosphere. The mechanisms by which plants control the production of these compounds and that mediate perception of stressful conditions are still not fully understood. Here we summarise plant defence strategies from the cellular to ecosystem level, discuss their advantages and disadvantages for plant growth and development, elucidate the current state of research on the transport and regeneration capacity of defence metabolites, and outline insufficiently explored questions for further investigation.

Comparative Transcriptomic and Lipidomic Analysis of Fatty Acid Accumulation in Three Camellia oleifera Varieties During Seed Maturing

Camellia oleifera, a major woody oil crop in China, produces tea oil rich in unsaturated fatty acids, earning it names like liquid gold and eastern olive oil. This study provides an integrated investigation of the transcriptome and lipidome within seeds at the maturing process across three C. oleifera varieties, revealing a significant relationship between fatty acid production and genes involved in lipid synthesis. Through transcriptomic analysis, 26,344 genes with varied expression were found. Functional enrichment analysis highlighted that pathways related to starch and sucrose metabolism, plant hormone signal transduction, and lipid accumulation were highly enriched among the differentially expressed genes. Coordinated high expression of key genes (ACCase, KAS I, KAS II, KAS III, KAR, HAD, EAR, SAD, LPAAT, LACS, DGAT, PDAT) during the late maturation stage contributes largely to high oil content. Additionally, expression variations of SAD and FADs among different varieties were explored. The analysis suggests that high expression of genes such as FAD3, FAD7, and FAD8 notably increased linolenic acid content. This research provides new insights into the molecular mechanisms of oil biosynthesis in C. oleifera, offering valuable references for improving yield and quality.

Elevated nitrogen fertilization differentially affects jojoba wax phytochemicals, fatty acids and fatty alcohols

Jojoba wax is gaining popularity among cosmetics consumers for its skin wound healing and rejuvenation bioactivities, attributed to collagen and hyaluronic acid synthesis. However, information regarding wax phytochemical composition and quality parameters, as well as effect of cultivation practices, and fertilization in particular, on wax quality is limited. The aim of the current work was to study the effect of nitrogen (N) availability to jojoba plants on wax phytochemical composition and beneficial skin-related contents. For this, wax quality from a six-year fertilization experiment with five N application levels was evaluated. The chemical parameters included antioxidant activity, free fatty acid, total tocopherol, total phytosterol and oxidative stability, as well as fatty acid and fatty alcohol profile. Our results reveal that the majority of wax quality traits were affected by N fertilization level, either positively or negatively. Interestingly, while fatty acids were unaffected, fatty alcohol composition was significantly altered by N level. Additionally, fruit load also largely affected wax quality, and, due to jojoba's biennial alternate bearing cycles, harvest year significantly affected all measured parameters. Results shed light on the effects of N application on various biochemical constituents of jojoba wax, and imply that N availability should be considered part of the entire agricultural management plan to enhance wax quality. Some traits are also suggested as possible chemical quality parameters for jojoba wax.

Metabolomics-based profiling of five Salvia L. (Lamiaceae) species using untargeted data analysis workflow

INTRODUCTION

The genus Salvia L., a member of the family Lamiaceae, is a keystone genus with a wide range of medicinal properties. It possesses a rich metabolite source that has long been used to treat different disorders.

OBJECTIVES

Due to a deficiency of untargeted metabolomic profiling in the genus Salvia, this work attempts to investigate a comprehensive mass spectral library matching, computational data annotations, exclusive biomarkers, specific chemotypes, intraspecific metabolite profile variation, and metabolite enrichment by a case study of five medicinal species of Salvia.

MATERIAL AND METHODS

Aerial parts of each species were subjected to QTRAP liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis workflow based on untargeted metabolites. A comprehensive and multivariate analysis was acquired on the metabolite dataset utilizing MetaboAnalyst 6.0 and the Global Natural Products Social Molecular Networking (GNPS) Web Platform.

RESULTS

The untargeted approach empowered the identification of 117 metabolites by library matching and 92 nodes annotated by automated matching. A machine learning algorithm as substructural topic modeling, MS2LDA, was further implemented to explore the metabolite substructures, resulting in four Mass2Motifs. The automated library newly discovered a total of 23 metabolites. In addition, 87 verified biomarkers of library matching, 58 biomarkers of GNPS annotations, and 11 specific chemotypes were screened.

CONCLUSION

Integrative spectral library matching and automated annotation by the GNPS platform provide comprehensive metabolite profiling through a workflow. In addition, QTRAP LC-MS/MS with multivariate analysis unveiled reliable information about inter and intraspecific levels of differentiation. The rigorous investigation of metabolite profiling presents a large-scale overview and new insights for chemotaxonomy and pharmaceutical studies.

Insights into Bacillus zanthoxyli HS1-mediated systemic tolerance: multifunctional implications for enhanced plant tolerance to abiotic stresses

Abiotic stresses significantly impact agricultural productivity and food security. Innovative strategies, including the use of plant-derived compounds and plant growth-promoting rhizobacteria (PGPR), are necessary to enhance plant resilience. This study delved into how Bacillus zanthoxyli HS1 (BzaHS1) and BzaHS1-derived volatile organic compounds (VOC) conferred systemic tolerance against salt and heat stresses in cabbage and cucumber plants. Direct application of a BzaHS1 strain or exposure of BzaHS1-derived VOC to cabbage and cucumber plants promoted seedling growth under stressed conditions. This induced systemic tolerance was associated with increased mRNA expression and enzymatic activities of superoxide dismutase (EC 1.15.1.1), catalase (EC 1.11.1.6), or ascorbate peroxidase (EC 1.11.1.1), leading to a reduction in oxidative stress in cabbage and cucumber plants. Plants co-cultured with BzaHS1 and exposed to BzaHS1-derived VOC triggered the accumulation of callose and minimized stomatal opening in response to high salt and temperature stresses, respectively. In contrast, exogenous treatment of azelaic acid, a well-characterized plant defense primer, had no significant impact on the seedling growth of cabbage and cucumber plants grown under abiotic stress conditions. Taken together, BzaHS1 and its VOC show potential for enhancing plant tolerance responses to salt and heat stresses through modulation of osmotic stress-regulatory networks.

The alphabet of sea fennel: Comprehensive phytochemical characterisation of Croatian populations of Crithmum maritimum L

Extreme environmental conditions affect the synthesis and accumulation of bioactive metabolites in halophytic plants. The aim of this study was to investigate the presence and quantity of key health-promoting phytochemicals in Croatian sea fennel, one of the most popular Mediterranean halophytes with a wide range of uses. The EOs were characterised by a high content of limonene (up to 93%), while the fatty acid profile shows a low content of oleic acid and the presence of valuable linoleic acid (ω-6) and linolenic acid (ω-3) in high percentages. The dominances of lutein and α-tocopherol were also confirmed in all samples. The results confirm the great variability in the chemistry of sea fennel populations in the Mediterranean region, with significant differences in the composition of the Croatian samples compared to the others, as well as the presence and high concentrations of the analysed bioactive compounds that contribute to the plant's health-promoting attributes.

Unveiling the "hidden quality" of the walnut pellicle: a precious source of bioactive lipids

Tree nut consumption has been widely associated with various health benefits, with walnuts, in particular, being linked with improved cardiovascular and neurological health. These benefits have been attributed to walnuts' vast array of phenolic antioxidants and abundant polyunsaturated fatty acids. However, recent studies have revealed unexpected clinical outcomes related to walnut consumption, which cannot be explained simply with the aforementioned molecular hallmarks. With the goal of discovering potential molecular sources of these unexplained clinical outcomes, an exploratory untargeted metabolomics analysis of the isolated walnut pellicle was conducted. This analysis revealed a myriad of unusual lipids, including oxylipins and endocannabinoids. These lipid classes, which are likely present in the pellicle to enhance the seeds' defenses due to their antimicrobial properties, also have known potent bioactivities as mammalian signaling molecules and homeostatic regulators. Given the potential value of this tissue for human health, with respect to its "bioactive" lipid fraction, we sought to quantify the amounts of these compounds in pellicle-enriched waste by-products of mechanized walnut processing in California. An impressive repertoire of these compounds was revealed in these matrices, and in notably significant concentrations. This discovery establishes these low-value agriculture wastes promising candidates for valorization and translation into high-value, health-promoting products; as these molecules represent a potential explanation for the unexpected clinical outcomes of walnut consumption. This "hidden quality" of the walnut pellicle may encourage further consumption of walnuts, and walnut industries may benefit from a revaluation of abundant pellicle-enriched waste streams, leading to increased sustainability and profitability through waste upcycling.

Comprehensive Review of Olea europaea: A Holistic Exploration into Its Botanical Marvels, Phytochemical Riches, Therapeutic Potentials, and Safety Profile

Human health is now inextricably linked to lifestyle choices, which can either protect or predispose people to serious illnesses. The Mediterranean diet, characterized by the consumption of various medicinal plants and their byproducts, plays a significant role in protecting against ailments such as oxidative stress, cancer, and diabetes. To uncover the secrets of this natural treasure, this review seeks to consolidate diverse data concerning the pharmacology, toxicology, phytochemistry, and botany of Olea europaea L. (O. europaea). Its aim is to explore the potential therapeutic applications and propose avenues for future research. Through web literature searches (using Google Scholar, PubMed, Web of Science, and Scopus), all information currently available on O. europaea was acquired. Worldwide, ethnomedical usage of O. europaea has been reported, indicating its effectiveness in treating a range of illnesses. Phytochemical studies have identified a range of compounds, including flavanones, iridoids, secoiridoids, flavonoids, triterpenes, biophenols, benzoic acid derivatives, among others. These components exhibit diverse pharmacological activities both in vitro and in vivo, such as antidiabetic, antibacterial, antifungal, antioxidant, anticancer, and wound-healing properties. O. europaea serves as a valuable source of conventional medicine for treating various conditions. The findings from pharmacological and phytochemical investigations presented in this review enhance our understanding of its therapeutic potential and support its potential future use in modern medicine.

Influence of Silver Nanoparticles on the Metabolites of Two Transgenic Soybean Varieties: An NMR-Based Metabolomics Approach

This study investigated the effect of AgNPs and AgNO3, at concentrations equivalent, on the production of primary and secondary metabolites on transgenic soybean plants through an NMR-based metabolomics. The plants were cultivated in a germination chamber following three different treatments: T0 (addition of water), T1 (addition of AgNPs), and T2 (addition of AgNO3). Physiological characteristics, anatomical analyses through microscopic structures, and metabolic profile studies were carried out to establish the effect of abiotic stress on these parameters in soybean plants. Analysis of the 1H NMR spectra revealed the presence of amino acids, organic acids, sugars, and polyphenols. The metabolic profiles of plants with AgNP and AgNO3 were qualitatively similar to the metabolic profile of the control group, suggesting that the application of silver does not affect secondary metabolites. From the PCA, it was possible to differentiate the three treatments applied, mainly based on the content of fatty acids, pinitol, choline, and betaine.

A new method based on melatonin-mediated seed germination to quickly remove pesticide residues and improve the nutritional quality of contaminated grains

In the present study, we attempted to use melatonin combined with germination treatment to remove pesticide residues from contaminated grains. High levels of pesticide residues were detected in soybean seeds after soaking with chlorothalonil (10 mM) and malathion (1 mM) for 2 hours. Treatment with 50 μM melatonin for 5 days completely removed the pesticide residues, while in the control group, only 61-71% of pesticide residues were removed from soybean sprouts. Compared with the control, melatonin treatment for 7 days further increased the content of ascorbic acid (by 48-66%), total phenolics (by 52-68%), isoflavones (by 22-34%), the total antioxidant capacity (by 37-40%), and the accumulated levels of unsaturated fatty acids (C18:1, C18:2, and C18:3) (by 17-30%) in soybean sprouts. Moreover, melatonin treatment further increased the accumulation of ten components of phenols and isoflavones in soybean sprouts relative to those in the control. The ability of melatonin to accelerate the degradation of pesticide residues and promote the accumulation of antioxidant metabolites might be related to its ability to trigger the glutathione detoxification system in soybean sprouts. Melatonin promoted glutathione synthesis (by 49-139%) and elevated the activities of glutathione-S-transferase (by 24-78%) and glutathione reductase (by 38-61%). In summary, we report a new method in which combined treatment by melatonin and germination rapidly degrades pesticide residues in contaminated grains and improves the nutritional quality of food.

In Silico Identification and Characterization of Fatty Acid Desaturase (FAD) Genes in Argania spinosa L. Skeels: Implications for Oil Quality and Abiotic Stress

Fatty acid desaturase (FAD) is the key enzyme that leads to the formation of unsaturated fatty acids by introducing double bonds into hydrocarbon chains, and it plays a critical role in plant lipid metabolism. However, no data are available on enzyme-associated genes in argan trees. In addition, a candidate gene approach was adopted to identify and characterize the gene sequences of interest that are potentially involved in oil quality and abiotic stress. Based on phylogenetic analyses, 18 putative FAD genes of Argania spinosa L. (AsFAD) were identified and assigned to three subfamilies: stearoyl-ACP desaturase (SAD), Δ-12 desaturase (FAD2/FAD6), and Δ-15 desaturase (FAD3/FAD7). Furthermore, gene structure and motif analyses revealed a conserved exon-intron organization among FAD members belonging to the various oil crops studied, and they exhibited conserved motifs within each subfamily. In addition, the gene structure shows a wide variation in intron numbers, ranging from 0 to 8, with two highly conserved intron phases (0 and 1). The AsFAD and AsSAD subfamilies consist of three (H(X)2-4H, H(X)2-3HH, and H/Q (X)2-3HH) and two (EEN(K)RHG and DEKRHE) conserved histidine boxes, respectively. A set of primer pairs were designed for each FAD gene, and tested on DNA extracted from argan leaves, in which all amplicons of the expected size were produced. These findings of candidate genes in A spinosa L. will provide valuable knowledge that further enhances our understanding of the potential roles of FAD genes in the quality of oil and abiotic stress in the argan tree.

Looking into the lipid profile of avocado and byproducts: Using lipidomics to explore value-added compounds

Consumer priorities in healthy diets and lifestyle boosted the demand for nutritious and functional foods as well as plant-based ingredients. Avocado has become a food trend due to its nutritional and functional values, which in turn is increasing its consumption and production worldwide. Avocado edible portion has a high content of lipids, with the pulp and its oil being rich in monounsaturated fatty acids and essential omega - 3 and omega - 6 polyunsaturated fatty acids (PUFA). These fatty acids are mainly esterified in triacylglycerides, the major lipids in pulp, but also in minor components such as polar lipids (phospholipids and glycolipids). Polar lipids of avocado have been overlooked despite being recently highlighted with functional properties as well. The growth in the industry of avocado products is generating an increased amount of their byproducts, such as seed and peels (nonedible portions), still undervalued. The few studies on avocado byproducts pointed out that they also contain interesting lipids, with seeds particularly rich in polar lipids bearing PUFA, and thus can be reused as a source of add-value phytochemical. Mass spectrometry-based lipidomics approaches appear as an essential tool to unveil the complex lipid signature of avocado and its byproducts, contributing to the recognition of value-added lipids and opening new avenues for their use in novel biotechnological applications. The present review provides an up-to-date overview of the lipid signature from avocado pulp, peel, seed, and its oils.

Shoots and Turions of Aquatic Plants as a Source of Fatty Acids

BACKGROUND

Fatty acids are essential for human health. Currently, there is a search for alternative sources of fatty acids that could supplement such sources as staple crops or fishes. Turions of aquatic plants accumulate a variety of substances such as starch, free sugars, amino acids, reserve proteins and lipids. Our aim is to see if turions can be a valuable source of fatty acids.

METHODS

Overwintering shoots and turions of aquatic carnivorous plants were collected. The plant material was extracted with hexane. The oils were analyzed using a gas chromatograph with mass spectrometer.

RESULTS

The dominant compound in all samples was linolenic acid. The oil content was different in turions and shoots. The oil content of the shoots was higher than that of the turions, but the proportion of fatty acids in the oils from the shoots was low in contrast to the oils from the turions. The turions of Utricularia species were shown to be composed of about 50% fatty acids.

CONCLUSIONS

The turions of Utricularia species can be used to obtain oil with unsaturated fatty acids. In addition, the high fatty acid content of turions may explain their ability to survive at low temperatures.

Physiological, Transcriptome, and Metabolome Analyses Reveal the Tolerance to Cu Toxicity in Red Macroalgae Gracilariopsis lemaneiformis

Heavy metal copper (Cu) will inevitably impact the marine macroalgae Gracilariopsis lemaneiformis (G. lemaneiformis), which is a culture of economic importance along China's coastline. In this study, the detoxification mechanism of Cu stress on G. lemaneiformis was revealed by assessing physiological indicators in conjunction with transcriptome and metabolome analyses at 1 d after Cu stress. Our findings revealed that 25 μM Cu stimulated ROS synthesis and led to the enzymatic oxidation of arachidonic acid residues. This process subsequently impeded G. lemaneiformis growth by suppressing photosynthesis, nitrogen metabolism, protein synthesis, etc. The entry of Cu ions into the algae was facilitated by ZIPs and IRT transporters, presenting as Cu2+. Furthermore, there was an up-regulation of Cu efflux transporters HMA5 and ABC family transporters to achieve compartmentation to mitigate the toxicity. The results revealed that G. lemaneiformis elevated the antioxidant enzyme superoxide dismutase and ascorbate-glutathione cycle to maintain ROS homeostasis. Additionally, metabolites such as flavonoids, 3-O-methylgallic acid, 3-hydroxy-4-keto-gama-carotene, and eicosapentaenoic acid were up-regulated compared with the control, indicating that they might play roles in response to Cu stress. In summary, this study offers a comprehensive insight into the detoxification mechanisms driving the responses of G. lemaneiformis to Cu exposure.

Comparative transcriptional analysis of Persea americana MYB, WRKY and AP2/ERF transcription factors following Phytophthora cinnamomi infection

Plant cells undergo extensive transcriptional reprogramming following pathogen infection, with these reprogramming patterns becoming more complex when pathogens, such as hemibiotrophs, exhibit different lifestyles. These transcriptional changes are often orchestrated by MYB, WRKY and AP2/ERF transcription factors (TFs), which modulate both growth and defence-related gene expression. Transcriptional analysis of defence-related genes in avocado (Persea americana) infected with Phytophthora cinnamomi indicated differential immune response activation when comparing a partially resistant and susceptible rootstock. This study identified 226 MYB, 82 WRKY, and 174 AP2/ERF TF-encoding genes in avocado, using a genome-wide approach. Phylogenetic analysis revealed substantial sequence conservation within TF groups underscoring their functional significance. RNA-sequencing analysis in a partially resistant and susceptible avocado rootstock infected with P. cinnamomi was indicative of an immune response switch occurring in either rootstock after 24 and 6 h post-inoculation, respectively. Different clusters of co-expressed TF genes were observed at these times, suggesting the activation of necrotroph-related immune responses at varying intervals between the two rootstocks. This study aids our understanding of avocado immune response activation following P. cinnamomi infection, and the role of the TFs therein, elucidating the transcriptional reprogramming disparities between partially resistant and susceptible rootstocks.

Romanian Wild-Growing Chelidonium majus-An Emerging Approach to a Potential Antimicrobial Engineering Carrier System Based on AuNPs: In Vitro Investigation and Evaluation

Novel nanotechnology based on herbal products aspires to be a high-performing therapeutic platform. This study reports the development of an original engineering carrier system that jointly combines the pharmacological action of Chelidonium majus and AuNPs, with unique properties that ensure that the limitations imposed by low stability, toxicity, absorption, and targeted and prolonged release can be overcome. The metabolite profile of Romanian wild-grown Chelidonium majus contains a total of seventy-four phytochemicals belonging to eight secondary metabolite categories, including alkaloids, amino acids, phenolic acids, flavonoids, carotenoids, fatty acids, sterols, and miscellaneous others. In this study, various techniques (XRD, FTIR, SEM, DLS, and TG/DTG) were employed to investigate his new carrier system's morpho-structural and thermal properties. In vitro assays were conducted to evaluate the antioxidant potential and release profile. The results indicate 99.9% and 94.4% dissolution at different pH values for the CG-AuNPs carrier system and 93.5% and 85.26% for greater celandine at pH 4 and pH 7, respectively. Additionally, three in vitro antioxidant assays indicated an increase in antioxidant potential (flavonoid content 3.8%; FRAP assay 24.6%; and DPPH 24.4%) of the CG-AuNPs carrier system compared to the herb sample. The collective results reflect the system's promising perspective as a new efficient antimicrobial and anti-inflammatory candidate with versatile applications, ranging from target delivery systems, oral inflammation (periodontitis), and anti-age cosmetics to extending the shelf lives of products in the food industry.

Spatiotemporal metabolic responses to water deficit stress in distinct leaf cell-types of poplar

The impact of water-deficit (WD) stress on plant metabolism has been predominantly studied at the whole tissue level. However, plant tissues are made of several distinct cell types with unique and differentiated functions, which limits whole tissue 'omics'-based studies to determine only an averaged molecular signature arising from multiple cell types. Advancements in spatial omics technologies provide an opportunity to understand the molecular mechanisms underlying plant responses to WD stress at distinct cell-type levels. Here, we studied the spatiotemporal metabolic responses of two poplar (Populus tremula× P. alba) leaf cell types -palisade and vascular cells- to WD stress using matrix-assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI). We identified unique WD stress-mediated metabolic shifts in each leaf cell type when exposed to early and prolonged WD stresses and recovery from stress. During water-limited conditions, flavonoids and phenolic metabolites were exclusively accumulated in leaf palisade cells. However, vascular cells mainly accumulated sugars and fatty acids during stress and recovery conditions, respectively, highlighting the functional divergence of leaf cell types in response to WD stress. By comparing our MALDI-MSI metabolic data with whole leaf tissue gas chromatography-mass spectrometry (GC-MS)-based metabolic profile, we identified only a few metabolites including monosaccharides, hexose phosphates, and palmitic acid that showed a similar accumulation trend at both cell-type and whole leaf tissue levels. Overall, this work highlights the potential of the MSI approach to complement the whole tissue-based metabolomics techniques and provides a novel spatiotemporal understanding of plant metabolic responses to WD stress. This will help engineer specific metabolic pathways at a cellular level in strategic perennial trees like poplars to help withstand future aberrations in environmental conditions and to increase bioenergy sustainability.

Fatty Acid Profiling as a Tool for Fostering the Traceability of the Halophyte Plant Salicornia ramosissima and Contributing to Its Nutritional Valorization

Salicornia ramosissima, commonly known as glasswort or sea asparagus, is a halophyte plant cultivated for human consumption that is often referred to as a sea vegetable rich in health-promoting n-3 fatty acids (FAs). Yet, the effect of abiotic conditions, such as salinity and temperature, on the FA profile of S. ramosissima remains largely unknown. These factors can potentially shape its nutritional composition and yield unique fatty acid signatures that can reveal its geographical origin. In this context, samples of S. ramosissima were collected from four different locations along the coastline of mainland Portugal and their FAs were profiled through gas chromatography-mass spectrometry. The lipid extracts displayed a high content of essential FAs, such as 18:2n-6 and 18:3n-3. In addition to an epoxide fatty acid exclusively identified in samples from the Mondego estuary, the relative abundance of FAs varied between origin sites, revealing that FA profiles can be used as site-specific lipid fingerprints. This study highlights the role of abiotic conditions on the nutritional profile of S. ramosissima and establishes FA profiling as a potential avenue to trace the geographic origin of this halophyte plant. Overall, the present approach can make origin certification possible, safeguard quality, and enhance consumers' trust in novel foods.

An Innovative Approach to a Potential Neuroprotective Sideritis scardica-Clinoptilolite Phyto-Nanocarrier: In Vitro Investigation and Evaluation

The cutting-edge field of nanomedicine combines the power of medicinal plants with nanotechnology to create advanced scaffolds that boast improved bioavailability, biodistribution, and controlled release. In an innovative approach to performant herb nanoproducts, Sideritis scardica Griseb and clinoptilolite were used to benefit from the combined action of both components and enhance the phytochemical's bioavailability, controlled intake, and targeted release. A range of analytical methods, such as SEM-EDX, FT-IR, DLS, and XDR, was employed to examine the morpho-structural features of the nanoproducts. Additionally, thermal stability, antioxidant screening, and in vitro release were investigated. Chemical screening of Sideritis scardica Griseb revealed that it contains a total of ninety-one phytoconstituents from ten chemical categories, including terpenoids, flavonoids, amino acids, phenylethanoid glycosides, phenolic acids, fatty acids, iridoids, sterols, nucleosides, and miscellaneous. The study findings suggest the potential applications as a promising aspirant in neurodegenerative strategy.

Ecotype-Specific and Correlated Seasonal Responses of Biomass Production, Non-Structural Carbohydrates, and Fatty Acids in Zostera marina

Seagrasses, which are marine flowering plants, provide numerous ecological services and goods. Zostera marina is the most widely distributed seagrass in temperate regions of the northern hemisphere, tolerant of a wide range of environmental conditions. This study aimed to (i) examine seasonal trends and correlations between key seagrass traits such as biomass production and biochemical composition, and (ii) compare seasonal adaptation of two ecotypes of Z. marina exposed to similar environmental conditions on the west coast of Ireland. During summer, plants accumulated higher levels of energetic compounds and levels of unsaturated fatty acids (FAs) decreased. Conversely, the opposite trend was observed during colder months. These findings indicate a positive seasonal correlation between the production of non-structural carbohydrates and saturated fatty acids (SFAs), suggesting that seagrasses accumulate and utilize both energetic compounds simultaneously during favorable and unfavorable environmental conditions. The two ecotypes displayed differential seasonal responses by adjusting plant morphology and production, the utilization of energetic reserves, and modulating unsaturation levels of fatty acids in seagrass leaves. These results underscore the correlated seasonal responses of key compounds, capturing ecotype-specific environmental adaptations and ecological strategies, emphasizing the robust utility of these traits as a valuable eco-physiological tool.

Association of the Arabidopsis oleoyl Δ12-desaturase FAD2 with pre-cis-Golgi stacks at endoplasmic reticulum-Golgi-exit sites

The unsaturation of phospholipids influences the function of membranes. In Arabidopsis thaliana, the oleoyl Δ12-desaturase FAD2 converts oleic (18:1Δ9 ) to linoleic acid (18:2Δ9,12 ) and influences phospholipid unsaturation in different cellular membranes. Despite its importance, the precise localization of Arabidopsis FAD2 has not been unambiguously described. As FAD2 is thought to modify phospholipid-associated fatty acids at the endoplasmic reticulum (ER), from where unsaturates are distributed to other cellular sites, we hypothesized that FAD2 locates to ER subdomains enabling trafficking of lipid intermediates through the secretory pathway. Fluorescent FAD2 fusions used to test this hypothesis were first assessed for functionality by heterologous expression in yeast (Saccharomyces cerevisiae), and in planta by Arabidopsis fad2 mutant rescue upon ectopic expression from an intrinsic FAD2 promoter fragment. Light sheet fluorescence, laser scanning confocal or spinning disc microscopy of roots, leaves, or mesophyll protoplasts showed the functional fluorescence-tagged FAD2 variants in flattened donut-shaped structures of ~0.5-1 μm diameter, in a pattern not resembling mere ER association. High-resolution imaging of coexpressed organellar markers showed fluorescence-tagged FAD2 in a ring-shaped pattern surrounding ER-proximal Golgi particles, colocalizing with pre-cis-Golgi markers. This localization required the unusual C-terminal retention signal of FAD2, and deletion or substitutions in this protein region resulted in relaxed distribution and diffuse association with the ER. The distinct association of FAD2 with pre-cis-Golgi stacks in Arabidopsis root and leaf tissue is consistent with a contribution of FAD2 to membrane lipid homeostasis through the secretory pathway, as verified by an increased plasma membrane liquid phase order in the fad2 mutant.

Modification of Fatty Acid Profile and Oil Contents Using Gene Editing in Oilseed Crops for a Changing Climate

Mutation breeding based on various chemical and physical mutagens induces and disrupts non-target loci. Hence, large populations were required for visual screening, but desired plants were rare and it was a further laborious task to identify desirable mutants. Generated mutant had high defect due to non-targeted mutation, with poor agronomic performance. Mutation techniques were augmented by targeted induced local lesions in genome (TILLING) facilitating the selection of desirable germplasm. On the other hand, gene editing through CRISPR/Cas9 allows knocking down genes for site-directed mutation. This handy technique has been exploited for the modification of fatty acid profile. High oleic acid genetic stocks were obtained in a broad range of crops. Moreover, genes involved in the accumulation of undesirable seed components such as starch, polysaccharide, and flavors were knocked down to enhance seed quality, which helps to improve oil contents and reduces the anti-nutritional component.

Genome-Wide Identification and Expression Analysis of the Stearoyl-Acyl Carrier Protein Δ9 Desaturase Gene Family under Abiotic Stress in Barley

Stearoyl-acyl carrier protein (ACP) Δ9 desaturase (SAD) is a critical fatty acid dehydrogenase in plants, playing a prominent role in regulating the synthesis of unsaturated fatty acids (UFAs) and having a significant impact on plant growth and development. In this study, we conducted a comprehensive genomic analysis of the SAD family in barley (Hordeum vulgare L.), identifying 14 HvSADs with the FA_desaturase_2 domain, which were divided into four subgroups based on sequence composition and phylogenetic analysis, with members of the same subgroup possessing similar genes and motif structures. Gene replication analysis suggested that tandem and segmental duplication may be the major reasons for the expansion of the SAD family in barley. The promoters of HvSADs contained various cis-regulatory elements (CREs) related to light, abscisic acid (ABA), and methyl jasmonate (MeJA). In addition, expression analysis indicated that HvSADs exhibit multiple tissue expression patterns in barley as well as different response characteristics under three abiotic stresses: salt, drought, and cold. Briefly, this evolutionary and expression analysis of HvSADs provides insight into the biological functions of barley, supporting a comprehensive analysis of the regulatory mechanisms of oil biosynthesis and metabolism in plants under abiotic stress.

The RNA landscape of Dunaliella salina in response to short-term salt stress

Using the halotolerant green microalgae Dunaliella salina as a model organism has special merits, such as a wide range of salt tolerance, unicellular organism, and simple life cycle and growth conditions. These unique characteristics make it suitable for salt stress study. In order to provide an overview of the response of Dunaliella salina to salt stress and hopefully to reveal evolutionarily conserved mechanisms of photosynthetic organisms in response to salt stress, the transcriptomes and the genome of the algae were sequenced by the second and the third-generation sequencing technologies, then the transcriptomes under salt stress were compared to the transcriptomes under non-salt stress with the newly sequenced genome as the reference genome. The major cellular biological processes that being regulated in response to salt stress, include transcription, protein synthesis, protein degradation, protein folding, protein modification, protein transport, cellular component organization, cell redox homeostasis, DNA repair, glycerol synthesis, energy metabolism, lipid metabolism, and ion homeostasis. This study gives a comprehensive overview of how Dunaliella salina responses to salt stress at transcriptomic level, especially characterized by the nearly ubiquitous up-regulation of the genes involving in protein folding, DNA repair, and cell redox homeostasis, which may confer the algae important mechanisms to survive under salt stress. The three fundamental biological processes, which face huge challenges under salt stress, are ignored by most scientists and are worth further deep study to provide useful information for breeding economic important plants competent in tolerating salt stress, other than only depending on the commonly acknowledged osmotic balance and ion homeostasis.

Prospects of chloroplast metabolic engineering for developing nutrient-dense food crops

Addressing nutritional deficiencies in food crops through biofortification is a sustainable approach to tackling malnutrition. Biofortification is continuously being attempted through conventional breeding as well as through various plant biotechnological interventions, ranging from molecular breeding to genetic engineering and genome editing for enriching crops with various health-promoting metabolites. Genetic engineering is used for the rational incorporation of desired nutritional traits in food crops and predominantly operates through nuclear and chloroplast genome engineering. In the recent past, chloroplast engineering has been deployed as a strategic tool to develop model plants with enhanced nutritional traits due to the various advantages it offers over nuclear genome engineering. However, this approach needs to be extended for the nutritional enhancement of major food crops. Further, this platform could be combined with strategies, such as synthetic biology, chloroplast editing, nanoparticle-mediated rapid chloroplast transformation, and horizontal gene transfer through grafting for targeting endogenous metabolic pathways for overproducing native nutraceuticals, production of biopharmaceuticals, and biosynthesis of designer nutritional compounds. This review focuses on exploring various features of chloroplast genome engineering for nutritional enhancement of food crops by enhancing the levels of existing metabolites, restoring the metabolites lost during crop domestication, and introducing novel metabolites and phytonutrients needed for a healthy daily diet.

Under flooding conditions, controlled-release fertiliser coated microplastics affect the growth and accumulation of cadmium in rice by increasing the fluidity of cadmium and interfering with metabolic pathways

The combined pollution of microplastics (MPs) and Cd can affect plant growth and development and Cd accumulation, with most studies focusing on dryland soil. However, the effects of polyurethane (PU) controlled-release fertiliser coated MPs (PU MPs), which widely exist in rice systems, coupled with Cd on plant growth and Cd accumulation under flooding conditions are still unknown. Therefore, in the present study, in situ techniques were used to systematically study the effects of PU MPs and Cd coupling on the physiological and biochemical performance, metabolomics characteristics, rhizosphere bacterial community, and Cd bioavailability of rice in different soil types (red soil/cinnamon soil). The results showed that the effects of PU MPs on rice growth and Cd accumulation were concentration-dependent, especially in red soil. High PU concentration (1 %) inhibited rice root growth significantly (44 %). The addition of PU MPs inhibited photosynthetically active radiation, net photosynthesis, and transpiration rate of rice, mainly with low concentration (0.1 %) in red soil and high concentration (1 %) in cinnamon soil. PU MPs can enhance the expression of Cd resistance genes (cadC and copA) in soil, enhance the mobility of Cd, and affect the metabolic pathways of metabolites in the rhizosphere soil (red soil: fatty acid metabolism; cinnamon soil: amino acid degradation, heterobiodegradation, and nucleotide metabolism) to promote Cd absorption in rice. Especially in red soil, Cd accumulation in the root and aboveground parts of rice after the addition of high concentration PU (1 %) was 1.7 times and 1.3 times, respectively, that of the control (p < 0.05). Simultaneously, microorganisms can affect rice growth and Cd bioavailability by affecting functional bacteria related to carbon, iron, sulfur, and manganese. The results of the present study provide novel insights into the potential effects of PU MPs coupled with Cd on plants, rhizosphere bacterial communities, and Cd bioavailability.

Osmotic stress-induced localisation switch of CBR1 from mitochondria to the endoplasmic reticulum triggers ATP production via β-oxidation to respond to osmotic shock

Drought and high salinity are major environmental factors that reduce plant growth and development, leading to loss of plant productivity in agriculture. Under these stress conditions, photosynthesis is greatly suppressed despite the high cellular energy cost of stress response processes. Currently, the process that allows plants to secure the energy required for osmotic stress responses remains elusive. Here, we provide evidence that cytochrome b5 reductase 1 (CBR1), a cytochrome b5 reductase, plays an important role in ATP production in response to NaCl and dehydration stresses. Overexpression and loss of function of CBR1 led to enhanced resistance and sensitivity, respectively, to osmotic stress. Upon exposure to osmotic stress, CBR1 was localised to the endoplasmic reticulum (ER) instead of to mitochondria, where it was localised under normal conditions. Transgenic plants overexpressing ER-targeted CBR1 showed enhanced resistance to osmotic stress. Moreover, CBR1-ER and CBR1-OX plants, had higher levels of ATP and unsaturated fatty acids under osmotic stress. However, these effects were abrogated by thioridazine and 2-deoxy glucose, inhibitors of β-oxidation and glycolysis, respectively. Based on these results, we propose that ER-localised CBR1 triggers ATP production via the production and β-oxidation of polyunsaturated fatty acids under osmotic stress.

Unveiling Fatty Acid Profiles of the Parasitic Plants Orobanche foetida Poiret. and Orobanche crenata Forsk. and Modulation of Faba Bean (Vicia faba L.) Fatty Acid Composition in Response to Orobanche Infestation

Broomrapes (Orobanche spp.) are root parasitic plants that threaten agricultural production in many parts of the world. In this study, the effect of two orobanche species, Orobanche crenata and O. foetida, on faba bean plants was studied in Tunisia. The two orobanche species inhibited both biomass production and pod formation, decreased the chlorophyll (Chl) content and total lipid (TL), and enhanced electrolyte leakage (EL) and lipid peroxidation. Concomitantly, orobanche parasitism induced a lower degree of fatty acid (FA) unsaturation due to a shift in the FA composition. On the other hand, with regard to orobanche seeds, oleic and linoleic acids were the predominant FA in the two orobanche species. After orobanche seed germination and penetration of host tissues, all the orobanche development stages showed a decrease in the TL content and changes in the FA composition in comparison to orobanche seeds. The level of TL was equal to or lower in all parasite development stages (except for S4) than that in the roots and leaves of healthy faba bean plants. These results suggest that the negative effect of orobanche infestation on faba bean development can be attributed to the reduced chlorophyll content and alteration in membrane stability attested by the reduced TL level and FA unsaturation.

The participation of vacuoles and the regulation of various metabolic pathways under acid stress promote the differentiation of chlamydospore in Trichoderma harzianum T4

AIMS

Chlamydospores are a special, differentiated type with high environmental resistance. Consequently, the chlamydospores of Trichoderma harzianum T4 can used to industrialize the latter. This study aimed to investigate the key factors affecting the sporulation type of T. harzianum T4 and the mechanisms underlying this effect.

METHODS AND RESULTS

In the liquid fermentation of T. harzianum T4, ammonium sulfate (AS) inhibited conidia formation and chlamydospore production. Fermentation tests revealed that acid stress induced sporulation type alteration. Transcriptomic analysis was used to evaluate the adaptation strategy and mechanism underlying spore type alteration under acid stress. The fermentation experiments involving the addition of amino acids revealed that branched-chain amino acids benefited conidia production, whereas β-alanine benefited chlamydospore production. Confocal microscope fluorescence imaging and chloroquine intervention demonstrated that vacuole function was closely related to chlamydospore production.

CONCLUSION

The sporulation type of T. harzianum T4 can be controlled by adjusting the fermentation pH. T. harzianum T4 cells employ various self-protection measures against strong acid stress, including regulating their metabolism to produce a large number of chlamydospores for survival.

A general overview of the multifactorial adaptation to cold: biochemical mechanisms and strategies

Cold environments are more frequent than people think. They include deep oceans, cold lakes, snow, permafrost, sea ice, glaciers, cold soils, cold deserts, caves, areas at elevations greater than 3000 m, and also artificial refrigeration systems. These environments are inhabited by a diversity of eukaryotic and prokaryotic organisms that must adapt to the hard conditions imposed by cold. This adaptation is multifactorial and includes (i) sensing the cold, mainly through the modification of the liquid-crystalline membrane state, leading to the activation of a two-component system that transduce the signal; (ii) adapting the composition of membranes for proper functions mainly due to the production of double bonds in lipids, changes in hopanoid composition, and the inclusion of pigments; (iii) producing cold-adapted proteins, some of which show modifications in the composition of amino acids involved in stabilizing interactions and structural adaptations, e.g., enzymes with high catalytic efficiency; and (iv) producing ice-binding proteins and anti-freeze proteins, extracellular polysaccharides and compatible solutes that protect cells from intracellular and extracellular ice. However, organisms also respond by reprogramming their metabolism and specifically inducing cold-shock and cold-adaptation genes through strategies such as DNA supercoiling, distinctive signatures in promoter regions and/or the action of CSPs on mRNAs, among others. In this review, we describe the main findings about how organisms adapt to cold, with a focus in prokaryotes and linking the information with findings in eukaryotes.

Progressive drought alters the root exudate metabolome and differentially activates metabolic pathways in cotton (Gossypium hirsutum)

Root exudates comprise various primary and secondary metabolites that are responsive to plant stressors, including drought. As increasing drought episodes are predicted with climate change, identifying shifts in the metabolome profile of drought-induced root exudation is necessary to understand the molecular interactions that govern the relationships between plants, microbiomes, and the environment, which will ultimately aid in developing strategies for sustainable agriculture management. This study utilized an aeroponic system to simulate progressive drought and recovery while non-destructively collecting cotton (Gossypium hirsutum) root exudates. The molecular composition of the collected root exudates was characterized by untargeted metabolomics using Fourier-Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR MS) and mapped to the Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. Over 700 unique drought-induced metabolites were identified throughout the water-deficit phase. Potential KEGG pathways and KEGG modules associated with the biosynthesis of flavonoid compounds, plant hormones (abscisic acid and jasmonic acid), and other secondary metabolites were highly induced under severe drought, but not at the wilting point. Additionally, the associated precursors of these metabolites, such as amino acids (phenylalanine and tyrosine), phenylpropanoids, and carotenoids, were also mapped. The potential biochemical transformations were further calculated using the data generated by FT-ICR MS. Under severe drought stress, the highest number of potential biochemical transformations, including methylation, ethyl addition, and oxidation/hydroxylation, were identified, many of which are known reactions in some of the mapped pathways. With the application of FT-ICR MS, we revealed the dynamics of drought-induced secondary metabolites in root exudates in response to drought, providing valuable information for drought-tolerance strategies in cotton.

Nutraceutical Potential of Leafy Vegetables Landraces at Microgreen, Baby, and Adult Stages of Development

Nutraceutical compounds present in leafy vegetables have gained substantial attention due to the health benefits they offer beyond their nutritional value. The biosynthesis, composition, and concentration of these compounds vary widely among leafy vegetables and carry the influence of genetic, agronomic, and environmental factors. Recently, micro-vegetables are gaining importance among consumers worldwide and are used in gastronomy at different development stages. Another tendency is the utilization of local genetic resources as an integral component of agricultural biodiversity crucial for sustainable production. The present study identifies the nutraceutical potential of 10 leafy vegetables at the microgreen, baby, and adult development stages using local genetic resources from the Spanish Vegetable Genebank (CITA, Aragón). Specifically, two landraces for each of the following crops were used: chard (Beta vulgaris), spinach (Spinacia oleracea), lettuce (Lactuca sativa), borage (Borago officinalis), and chicory (Cichorium intybus). The results reinforce the value of traditional local genetics and demonstrate the potential of these leafy vegetables as a source of functional compounds (fatty acids, vitamin C, carotenoids, polyphenols, antioxidant activity, and tocopherols). The observed variability depending on the crop and the developmental stage recommends the necessity of having a varied diet, since each leafy vegetable product offers a unique nutritional profile.

Trash to treasure: lactate and protein lactylation in maize root impacts response to drought

Lactate, protein lactylation (Kla), and specifically histone lactylation have recently been shown to regulate antipathogenic immune responses in mammals. Herein, after we confirmed the presence and accumulation of lactate in maize roots under drought conditions, a lactylome profiling analysis revealed that Kla modifications were invariably present in maize roots, that there were obvious differences in the lactylomes of drought-sensitive (B73) vs. drought-tolerant (Jing2416) lines, and that growing Jing2416 under drought conditions caused significant decreases in the lactylation of multiple enzymes responsible for fatty acid degradation. Inspired by findings of histone-Kla based epigenetic regulation of immune functions in animals, we initially discovered 37 Kla sites on 16 histones in the maize genome, and again detected obvious differential histone Kla-mediated trends between two lines by ChIP-Seq. Notably, only 2.7% of genes with differential histone Kla peaks detected during drought stress were commonly present in both lines, a finding demonstrating that abiotic stress triggers distinct epigenetic activities in diverse germplasm while also strongly supporting that a histone Kla layer of regulation is associated with physiological responses to drought stress. Interestingly, exogenous application of spermidine improved the drought tolerance of B73 and substantially altered the levels of lactate, protein lactylation, and histone Kla modification. Thus, beyond extending the known domain of Kla-based biochemical and epigenetic regulation from animal immunity to plant stress physiology, our study suggests the physiological, biochemical, and genetic function of "the best-known metabolic waste", lactate.

Systems-level proteomics and metabolomics reveals the diel molecular landscape of diverse kale cultivars

Kale is a group of diverse Brassicaceae species that are nutritious leafy greens consumed for their abundance of vitamins and micronutrients. Typified by their curly, serrated and/or wavy leaves, kale varieties have been primarily defined based on their leaf morphology and geographic origin, despite having complex genetic backgrounds. Kale is a very promising crop for vertical farming due to its high nutritional content; however, being a non-model organism, foundational, systems-level analyses of kale are lacking. Previous studies in kale have shown that time-of-day harvesting can affect its nutritional composition. Therefore, to gain a systems-level diel understanding of kale across its wide-ranging and diverse genetic landscape, we selected nine publicly available and commercially grown kale cultivars for growth under near-sunlight LED light conditions ideal for vertical farming. We then analyzed changes in morphology, growth and nutrition using a combination of plant phenotyping, proteomics and metabolomics. As the diel molecular activities of plants drive their daily growth and development, ultimately determining their productivity as a crop, we harvested kale leaf tissue at both end-of-day (ED) and end-of-night (EN) time-points for all molecular analyses. Our results reveal that diel proteome and metabolome signatures divide the selected kale cultivars into two groups defined by their amino acid and sugar content, along with significant proteome differences involving carbon and nitrogen metabolism, mRNA splicing, protein translation and light harvesting. Together, our multi-cultivar, multi-omic analysis provides new insights into the molecular underpinnings of the diel growth and development landscape of kale, advancing our fundamental understanding of this nutritious leafy green super-food for horticulture/vertical farming applications.

Anemochorous and zoochorous seeds of trees from the Brazilian savannas differ in fatty acid content and composition

Fatty acids (FAs) stored as triacylglycerols (TAGs) are an important source of carbon and energy for germination and seedling development, particularly for plants with small wind-dispersed seeds, allowing greater efficiency in storing both energy and carbon. These plants should be under strong selection to produce seeds rich in FAs and with large amounts of saturated FAs. Their closely packed single-chain configuration allows greater packing, more carbon and energy per unit mass, and are less costly to produce. Efficient carbon storage would be less crucial for zoochorous species, which can reach much larger seed sizes (mass). We analysed the transesterified FA profile from seeds of 22 anemochorous and zoochorous tree species from the Cerrado savannas of Central Brazil. We tested if seed FA content covaried with seed mass and if anemochorous and zoochorous seeds differed in FA contents and distribution. Fatty acids were an important seed source of carbon and energy for most species. Fifteen different FAs were identified. Oleic, linoleic and linolenic tended to be the predominant unsaturated FAs. Oleic acid corresponded to more than 60 % of the total transesterified FAs in seeds of Kielmeyera coriacea, Qualea dichotoma and Triplaris americana. Linoleic acid corresponded to more than 50 % of total FA in Dalbergia miscolobium, Parkia platycephala and Ferdinandusa elliptica while linolenic acid was the dominant component in Inga cylindrica. Across species, palmitic and stearic were the dominant saturated FAs. The only exception was lauric acid (68 % of total FA) in seeds of Qualea grandiflora. On a log10 scale, as the seed increased in mass, accumulation of FAs tends to proceed at a faster rate in anemochorous species than in zoochorous species. They also became increasingly richer in saturated FAs. Zoochorous species had seed TAGs with higher proportion of polyunsaturated FAs.

Comparative metabolomic analysis between tomato and halophyte plants under intercropping conditions

Halophyte-based intercropping appears nowadays as a valuable approach in soil remediation and agriculture. In this work, intercropping between the halophyte Arthrocaulon macrostachyum and tomato (Solanum lycopersicum var. Sargento) was studied in both plant species using comparative mass spectrometry-based metabolomics coupled to metabolic pathway predictions. A significant number of changes in metabolites was observed in the halophyte. In terms of alteration of specific metabolic pathways, intercropping conditions stimulated sugar and starch metabolisms in tomato, whereas in the halophyte, intercropping mainly altered amino acid-related pathways. In addition, arginine and proline metabolism were commonly affected in both tomato and halophyte plants. Moreover, metabolomic changes were associated with physiological alterations in tomato. In this sense, mild oxidative stress was induced in intercropped tomato plants, which, in turn, could trigger signaling events leading to plant adjustment to intercropping conditions. This study represents the first approach toward understanding intercropping interactions at the metabolome level and its effect on plant physiology, opening up prospects for further characterization of this crop cultivation strategy.

Comparative Transcriptome Profiling of CMS-D2 and CMS-D8 Systems Characterizes Fertility Restoration Genes Network in Upland Cotton

Resolving the genetic basis of fertility restoration for cytoplasmic male sterility (CMS) can improve the efficiency of three-line hybrid breeding. However, the genetic determinants of male fertility restoration in cotton are still largely unknown. This study comprehensively compared the full-length transcripts of CMS-D2 and CMS-D8 systems to identify potential genes linked with fertility restorer genes Rf₁ or Rf₂. Target comparative analysis revealed a higher percentage of differential genes in each restorer line as compared to their corresponding sterile and maintainer lines. An array of genes with specific expression in the restorer line of CMS-D2 had functional annotations related to floral development and pathway enrichments in various secondary metabolites, while specifically expressed genes in the CMS-D8 restorer line showed functional annotations related to anther development and pathway enrichment in the biosynthesis of secondary metabolites. Further analysis identified potentially key genes located in the target region of fertility restorer genes Rf₁ or Rf₂. In particular, Ghir_D05G032450 can be the candidate gene related to restorer gene Rf₁, and Ghir_D05G035690 can be the candidate gene associated with restorer gene Rf₂. Further gene expression validation with qRT-PCR confirmed the accuracy of our results. Our findings provide useful insights into decoding the potential regulatory network that retrieves pollen fertility in cotton and will help to further reveal the differences in the genetic basis of fertility restoration for two CMS systems.

Deuterium- and Alkyne-Based Bioorthogonal Raman Probes for In Situ Quantitative Metabolic Imaging of Lipids within Plants

Plants can rapidly respond to different stresses by activating multiple signaling and defense pathways. The ability to directly visualize and quantify these pathways in real time using bioorthogonal probes would have practical applications, including characterizing plant responses to both abiotic and biotic stress. Fluorescence-based labels are widely used for tagging of small biomolecules but are relatively bulky and with potential effects on their endogenous localization and metabolism. This work describes the use of deuterium- and alkyne-derived fatty acid Raman probes to visualize and track the real-time response of plants to abiotic stress within the roots. Relative quantification of the respective signals could be used to track their localization and overall real-time responses in their fatty acid pools due to drought and heat stress without labor-intensive isolation procedures. Their overall usability and low toxicity suggest that Raman probes have great untapped potential in the field of plant bioengineering.

Overexpression of the Purple Perilla (Perilla frutescens (L.)) FAD3a Gene Enhances Salt Tolerance in Soybean

The increasingly serious trend of soil salinization inhibits the normal growth and development of soybeans, leading to reduced yields and a serious threat to global crop production. Microsomal ω-3 fatty acid desaturase encoded by the FAD3 gene is a plant enzyme that plays a significant role in α-linolenic acid synthesis via regulating the membrane fluidity to better accommodate various abiotic stresses. In this study, PfFAD3a was isolated from perilla and overexpressed in soybeans driven by CaMV P35S, and the salt tolerance of transgenic plants was then evaluated. The results showed that overexpression of PfFAD3a increased the expression of PfFAD3a in both the leaves and seeds of transgenic soybean plants, and α-linolenic acid content also significantly increased; hence, it was shown to significantly enhance the salt tolerance of transgenic plants. Physiological and biochemical analysis showed that overexpression of PfFAD3a increased the relative chlorophyll content and PSII maximum photochemical efficiency of transgenic soybean plants under salt stress; meanwhile, a decreased accumulation of MDA, H₂O₂, and O2•-, increased the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbic acid peroxidase (APX), as well as the production of proline and soluble sugar. In summary, the overexpression of PfFAD3a may enhance the salt tolerance in transgenic soybean plants through enhanced membrane fluidity and through the antioxidant capacity induced by C18:3.

Integrated lipidomic and transcriptomic analyses reveal the mechanism of lipid biosynthesis and accumulation during seed development in sesame

Sesame is one of the most important oilseed crops and attracts significant attention because of its huge nutritional capacity. However, the molecular mechanisms underlying oil accumulation in sesame remains poorly understood. In this study, lipidomic and transcriptomic analyses in different stages of sesame seed (Luzhi No.1, seed oil content 56%) development were performed to gain insight into the regulatory mechanisms that govern differences in lipid composition, content, biosynthesis, and transport. In total, 481 lipids, including fatty acids (FAs, 38 species), triacylglycerol (TAG, 127 species), ceramide (33 species), phosphatidic acid (20 species), and diacylglycerol (17 species), were detected in developing sesame seed using gas and liquid chromatography-mass spectrometry. Most FAs and other lipids accumulated 21-33 days after flowering. RNA-sequence profiling in developing seed highlighted the enhanced expression of genes involved in the biosynthesis and transport of FAs, TAGs, and membrane lipids, which was similar to that seen during lipid accumulation. Through the differential expression analysis of genes involved in lipid biosynthesis and metabolism during seed development, several candidate genes were found to affect the oil content and FA composition of sesame seed, including ACCase, FAD2, DGAT, G3PDH, PEPCase, WRI1 and WRI1-like genes. Our study reveals the patterns of lipid accumulation and biosynthesis-related gene expression and lays an important foundation for the further exploration of sesame seed lipid biosynthesis and accumulation.

The use of chitosan oligosaccharide to improve artemisinin yield in well-watered and drought-stressed plants

Introduction

Artemisinin is a secondary metabolite well-known for its use in the treatment of malaria. It also displays other antimicrobial activities which further increase its interest. At present, Artemisia annua is the sole commercial source of the substance, and its production is limited, leading to a global deficit in supply. Furthermore, the cultivation of A. annua is being threatened by climate change. Specifically, drought stress is a major concern for plant development and productivity, but, on the other hand, moderate stress levels can elicit the production of secondary metabolites, with a putative synergistic interaction with elicitors such as chitosan oligosaccharides (COS). Therefore, the development of strategies to increase yield has prompted much interest. With this aim, the effects on artemisinin production under drought stress and treatment with COS, as well as physiological changes in A. annua plants are presented in this study.

Methods

Plants were separated into two groups, well-watered (WW) and drought-stressed (DS) plants, and in each group, four concentrations of COS were applied (0, 50,100 and 200 mg•L-1). Afterwards, water stress was imposed by withholding irrigation for 9 days.

Results

Therefore, when A. annua was well watered, COS did not improve plant growth, and the upregulation of antioxidant enzymes hindered the production of artemisinin. On the other hand, during drought stress, COS treatment did not alleviate the decline in growth at any concentration tested. However, higher doses improved the water status since leaf water potential (YL) improved by 50.64% and relative water content (RWC) by 33.84% compared to DS plants without COS treatment. Moreover, the combination of COS and drought stress caused damage to the plant's antioxidant enzyme defence, particularly APX and GR, and reduced the amount of phenols and flavonoids. This resulted in increased ROS production and enhanced artemisinin content by 34.40% in DS plants treated with 200 mg•L-1 COS, compared to control plants.

Conclusion

These findings underscore the critical role of ROS in artemisinin biosynthesis and suggest that COS treatment may boost artemisinin yield in crop production, even under drought conditions.

A Metabolome Analysis and the Immunity of Phlomis purpurea against Phytophthora cinnamomi

Phlomis purpurea grows spontaneously in the southern Iberian Peninsula, namely in cork oak (Quercus suber) forests. In a previous transcriptome analysis, we reported on its immunity against Phytophthora cinnamomi. However, little is known about the involvement of secondary metabolites in the P. purpurea defense response. It is known, though, that root exudates are toxic to this pathogen. To understand the involvement of secondary metabolites in the defense of P. purpurea, a metabolome analysis was performed using the leaves and roots of plants challenged with the pathogen for over 72 h. The putatively identified compounds were constitutively produced. Alkaloids, fatty acids, flavonoids, glucosinolates, polyketides, prenol lipids, phenylpropanoids, sterols, and terpenoids were differentially produced in these leaves and roots along the experiment timescale. It must be emphasized that the constitutive production of taurine in leaves and its increase soon after challenging suggests its role in P. purpurea immunity against the stress imposed by the oomycete. The rapid increase in secondary metabolite production by this plant species accounts for a concerted action of multiple compounds and genes on the innate protection of Phlomis purpurea against Phytophthora cinnamomi. The combination of the metabolome with the transcriptome data previously disclosed confirms the mentioned innate immunity of this plant against a devastating pathogen. It suggests its potential as an antagonist in phytopathogens' biological control. Its application in green forestry/agriculture is therefore possible.

Assessment of physicochemical parameters, bioactive compounds, biological activities, and nutritional value of the most two commercialized pollen types of date palm (Phoenix dactylifera L.) in Morocco

The pollen of date palm (Phoenix dactylifera L.) is known for its nutritional value and implications as a health-promoting component. Due to its low cost, date palm pollen crushed with its spadix is more widely commercialized and used in Morocco than pure date palm pollen free of spadix. Thus, this study aimed to assess the physicochemical and phytochemical parameters, biological activities, and nutritional value of the two pollen types: Pure date palm pollen and date palm pollen crushed with its spadix. Various physicochemical parameters were determined, including humidity, water activity (aw), total soluble solids, ash content, and color parameters (L*, a*, b*, C*ab, and hab). Additionally, the phenolic compound profiles were analyzed, and the in vitro antioxidant, enzyme inhibitory, and antidiabetic activities were assessed for both pure date palm pollen and date palm pollen crushed with its spadix. Furthermore, the nutritional value was evaluated by determining protein and carbohydrate contents, and mineral and fatty acid profiles. The results have revealed that pure date palm pollen had higher humidity, aw, L*, and hab color parameters than date palm pollen crushed with its spadix, but lower total soluble solid and ash contents. The main phenolic compounds in pure date palm pollen were ellagic acid, rutin, fisetin, and quercetin, whereas date palm pollen crushed with its spadix contained mainly catechin, chlorogenic acid, p-coumaric acid, ferulic acid, and rutin. Moreover, pure date palm pollen showed greater in vitro antioxidant activity, while date palm pollen crushed with its spadix had higher enzyme inhibitory and antidiabetic activities. PDPS was the richest source of proteins, carbohydrates, minerals, and saturated fatty acids, while date palm pollen crushed with its spadix was a better source of unsaturated fatty acids, which are mainly represented by linoleic acid. In conclusion, although date palm pollen crushed with its spadix is the most widely consumed type, its nutritional value is lower than that of pure date palm pollen. Thus, pure date palm pollen could potentially serve as a better source of many bioactive compounds, making it a viable supplement for various health applications.

Modifications in Ultrastructural Characteristics and Redox Status of Plants under Environmental Stress: A Review

The rate of global environmental change is unprecedented, with climate change causing an increase in the oscillation and intensification of various abiotic stress factors that have negative impacts on crop production. This issue has become an alarming global concern, especially for countries already facing the threat of food insecurity. Abiotic stressors, such as drought, salinity, extreme temperatures, and metal (nanoparticle) toxicities, are recognized as major constraints in agriculture, and are closely associated with the crop yield penalty and losses in food supply. In order to combat abiotic stress, it is important to understand how plant organs adapt to changing conditions, as this can help produce more stress-resistant or stress-tolerant plants. The investigation of plant tissue ultrastructure and subcellular components can provide valuable insights into plant responses to abiotic stress-related stimuli. In particular, the columella cells (statocytes) of the root cap exhibit a unique architecture that is easily recognizable under a transmission electron microscope, making them a useful experimental model for ultrastructural observations. In combination with the assessment of plant oxidative/antioxidative status, both approaches can shed more light on the cellular and molecular mechanisms involved in plant adaptation to environmental cues. This review summarizes life-threatening factors of the changing environment that lead to stress-related damage to plants, with an emphasis on their subcellular components. Additionally, selected plant responses to such conditions in the context of their ability to adapt and survive in a challenging environment are also described.

A necessary considering factor for breeding: growth-defense tradeoff in plants

Crop diseases cause enormous yield losses and threaten global food security. Deployment of resistant cultivars can effectively control the disease and to minimize crop losses. However, high level of genetic immunity to disease was often accompanied by an undesired reduction in crop growth and yield. Recently, literatures have been rapidly emerged in understanding the mechanism of disease resistance and development genes in crop plants. To determine how and why the costs and the likely benefit of resistance genes caused in crop varieties, we re-summarized the present knowledge about the crosstalk between plant development and disease resistance caused by those genes that function as plasma membrane residents, MAPK cassette, nuclear envelope (NE) channels components and pleiotropic regulators. Considering the growth-defense tradeoffs on the basis of current advances, finally, we try to understand and suggest that a reasonable balancing strategies based on the interplay between immunity with growth should be considered to enhance immunity capacity without yield penalty in future crop breeding.

Temporal transcriptome analysis reveals several key pathways involve in cadmium stress response in Nicotiana tabacum L

Tobacco has a strong cadmium (Cd) enrichment capacity, meaning that it can absorb large quantities from the environment, but too much Cd will cause damage to the plant. It is not yet clear how the plant can dynamically respond to Cd stress. Here, we performed a temporal transcriptome analysis of tobacco roots under Cd treatment from 0 to 48 h. The number of differentially expressed genes (DEGs) was found to change significantly at 3 h of Cd treatment, which we used to define the early and middle stages of the Cd stress response. The gene ontology (GO) term analysis indicates that genes related to photosynthesis and fatty acid synthesis were enriched during the early phases of the stress response, and in the middle phase biological process related to metal ion transport, DNA damage repair, and metabolism were enriched. It was also found that plants use precursor mRNA (pre-mRNA) processes to first resist Cd stress, and with the increasing of Cd treatment time, the overlapped genes number of DEGs and DAS increased, suggesting the transcriptional levels and post-transcriptional level might influence each other. This study allowed us to better understand how plants dynamically respond to cadmium stress at the transcriptional and post-transcriptional levels and provided a reference for the screening of Cd-tolerant genes in the future.

Acetic acid enhances drought tolerance more in female than in male willows

Drought is an important stress factor that limits plant growth and development. Female willows generally display stronger drought tolerance than males. The application of exogenous acetic acid (AA) has emerged as an efficient and eco-friendly approach to facilitate drought tolerance in willows. However, whether AA exerts sexually different effects on willows remains undefined. In this study, we comprehensively performed morphological and physiological analyses on three willow species, Salix rehderiana, Salix babylonica, and Salix matsudana, to investigate the sexually different responses to drought and AA. The results indicated that willow females were more drought-tolerant than males. AA application effectively enhanced willows' drought tolerance, and females applied with AA displayed greater root distribution and activity, stronger osmotic and antioxidant capacity and photosynthetic rate but less reactive oxygen species, or abscisic acid-mediated stomatal closure than males. In addition, AA application enhanced the jasmonic acid signaling pathway in females but inhibited it in males, conferring stronger drought defense capacity in female willows than in males. Overall, AA application improves drought tolerance more in female than in male willows, further enlarging the sexual differences in willows under drought-stressed conditions.

Antioxidant and Anti-Inflammatory Properties of Phytochemicals Found in the Yucca Genus

The Yucca genus encompasses about 50 species native to North America. Species within the Yucca genus have been used in traditional medicine to treat pathologies related to inflammation. Despite its historical use and the popular notion of its antioxidant and anti-inflammatory properties, there is a limited amount of research on this genus. To better understand these properties, this work aimed to analyze phytochemical composition through documentary research. This will provide a better understanding of the molecules and the mechanisms of action that confer such antioxidant and anti-inflammatory properties. About 92 phytochemicals present within the genus have reported antioxidant or anti-inflammatory effects. It has been suggested that the antioxidant and anti-inflammatory properties are mainly generated through its free radical scavenging activity, the inhibition of arachidonic acid metabolism, the decrease in TNF-α (Tumor necrosis factor-α), IL-6 (Interleukin-6), iNOS (Inducible nitric oxide synthase), and IL-1β (Interleukin 1β) concentration, the increase of GPx (Glutathione peroxidase), CAT (Catalase), and SOD (Superoxide dismutase) concentration, and the inhibition of the MAPK (Mitogen-Activated Protein Kinase), and NF-κB (Nuclear factor kappa B), and the activation of the Nrf2 (Nuclear factor erythroid 2–related factor) signaling pathway. These studies provide evidence of its use in traditional medicine against pathologies related to inflammation. However, more models and studies are needed to properly understand the activity of most plants within the genus, its potency, and the feasibility of its use to help manage or treat chronic inflammation.

Multi-omics Analysis of Young Portulaca oleracea L. Plants' Responses to High NaCl Doses Reveals Insights into Pathways and Genes Responsive to Salinity Stress in this Halophyte Species

Soil salinity is among the abiotic stressors that threaten agriculture the most, and purslane (Portulaca oleracea L.) is a dicot species adapted to inland salt desert and saline habitats that hyper accumulates salt and has high phytoremediation potential. Many researchers consider purslane a suitable model species to study the mechanisms of plant tolerance to drought and salt stresses. Here, a robust salinity stress protocol was developed and used to characterize the morphophysiological responses of young purslane plants to salinity stress; then, leaf tissue underwent characterization by distinct omics platforms to gain further insights into its response to very high salinity stress. The salinity stress protocol did generate different levels of stress by gradients of electrical conductivity at field capacity and water potential in the saturation extract of the substrate, and the morphological parameters indicated three distinct stress levels. As expected from a halophyte species, these plants remained alive under very high levels of salinity stress, showing salt crystal-like structures constituted mainly by Na+, Cl-, and K+ on and around closed stomata. A comprehensive and large-scale metabolome and transcriptome single and integrated analyses were then employed using leaf samples. The multi-omics integration (MOI) system analysis led to a data-set of 51 metabolic pathways with at least one enzyme and one metabolite differentially expressed due to salinity stress. These data sets (of genes and metabolites) are valuable for future studies aimed to deepen our knowledge on the mechanisms behind the high tolerance of this species to salinity stress. In conclusion, besides showing that this species applies salt exclusion already in young plants to support very high levels of salinity stress, the initial analysis of metabolites and transcripts data sets already give some insights into other salt tolerance mechanisms used by this species to support high levels of salinity stress.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43657-022-00061-2.