Lipid-Derived Aldehydes: New Key Mediators of Plant Growth and Stress Responses

Reclaiming Wolffia arrhiza as fish feed for the phytoremediation of aquaculture effluent

The aquaculture industry through the fisheries sector holds an important key aspect of food security. Despite its significance, it comes with environmental issues that cannot be avoided in most industrial activities, especially issues regarding water-related pollution. This study explores a novel dual-purpose approach, in which a floating species, Wolffia arrhizal, was applied for phyto-remediating aquaculture effluent and later followed by the evaluation of its potential as alternative fish feed. Different concentrations of contaminant loads were exposed to W. arrhiza plants for 7 days, and the best performance with removals of 15 % chemical oxygen demand (COD), 80 % biological oxygen demand (BOD), 99 % ammoniacal nitrogen (AN) and 94 % total suspended solids (TSS) were achieved in the treatment system using 0.1 g COD/g plant. The harvested plant biomass enriched with nutrients demonstrating strong potential for resource recovery within a circular economy framework, was then utilized in three separate fish feeding trials. Catfish were fed with 100 % commercial pallets; 50 % mixture of commercial pallets and 50 % W. arrhizal; and 100 % W. arrhiza. Results showed that W. arrhiza collected after phytoremediation treatment shows good potential as fish feed, but modification is needed in its formulation to ensure sufficient nutrient supply for fishes. This study highlights the dual potential of W. arrhiza as phytoremediator for aquaculture effluent and later being used as fish feed, contributing to both environmental protection and resource circularity in aquaculture.

Influence of Malted Chickpea on the Composition of Volatiles in Hummus

In recent years, research has shown that malting legume seeds can be a viable modification method; however, very few applications of legume malts are currently available. This research aimed to determine whether using malted chickpeas can significantly impact the volatile composition of the produced hummus, as aroma is one of the crucial factors in the acceptance of food products. Five chickpea malts produced by germination by a different amount of time (24 h, 48 h, 72 h, 96 h, and 120 h) were used as a substrate for the production of hummuses and were compared to the hummus produced from unmalted chickpeas. Hummuses produced from the chickpea malt germinated for 96 h and 120 h were characterized by a higher concentration of most volatiles than the control sample, while the hummuses produced from chickpea malts germinated for 24 h, 48 h, and 72 h were characterized by a lower concentration of volatiles.

The Aldehyde Dehydrogenase Superfamily in Brassica napus L.: Genome-Wide Identification and Expression Analysis Under Low-Temperature Conditions

The Aldehyde Dehydrogenase (ALDH) superfamily comprises a group of NAD+ or NADP+-dependent enzymes that play essential roles in responding to abiotic stresses in plants. In Brassica napus L., however, the increasing frequency of extremely low temperatures during winter in recent years has significantly affected both yield and quality. This study conducted a genome-wide screening of ALDH superfamily genes, analyzing their gene structures, evolutionary relationships, protein physicochemical properties, and expression patterns under low-temperature stress to explore the function of the ALDH superfamily gene in cold tolerance in Brassica napus L. A total of six BnALDH genes with significant differences in expression levels were verified utilizing quantitative real-time polymerase chain reaction (qRT-PCR), revealing that BnALDH11A2, BnALDH7B2, BnALDH3F5, BnALDH12A3, BnALDH2B6, and BnALDH7B3 all exhibited higher expression in cold-tolerant material 24W233 compared with cold-sensitive material 24W259. Additionally, a single nucleotide polymorphism (SNP) in the BnALDH11A2 promoter region shows differences between the cold-tolerant (24W233) and the cold-sensitive (24W259) Brassica napus varieties, and it may be associated with the cold tolerance of these two varieties. This comprehensive analysis offers valuable insights into the role of ALDH family genes in low-temperature stress adaptation in Brassica napus and offers genetic resources for the development of novel cold-tolerant cultivars.

Network analysis combined with genome-wide association study helps identification of genes related to amino acid contents in soybean

BACKGROUND

Additional to total protein content, the amino acid (AA) profile is important to the nutritional value of soybean seed. The AA profile in soybean seed is a complex quantitative trait controlled by multiple interconnected genes and pathways controlling the accumulation of each AA. With a total of 621 soybean germplasm, we used three genome-wide association study (GWAS)-based approaches to investigate the genomic regions controlling the AA content and profile in soybean. Among those approaches, the GWAS network analysis we implemented takes advantage of the relationships between specific AAs to identify the genetic control of AA profile.

RESULTS

For Approach I, GWAS were performed for the content of 24 single AAs under all environments combined. Significant SNPs grouping into 16 linkage disequilibrium (LD) blocks from 18 traits were identified. For Approach II, the individual AAs were grouped by five families according to their metabolic pathways and were examined based on the sum, ratios, and interactions of AAs within the same biochemical family. Significant SNPs grouping into 35 LD blocks were identified, with SNPs associated with traits from the same biochemical family often positioned on the same LD blocks. Approach III, a correlation-based network analysis, was performed to assess the empirical relationships among AAs. Two groups were described by the network topology, Group 1: Ala, Gly, Lys, available Lys (Alys), and Thr and Group 2: Ile and Tyr. Significant SNPs associated with a ratio of connected AAs or a ratio of a single AA to its fully or partially connected metabolic groups were identified within 9 LD blocks for Group 1 and 2 LD blocks for Group 2. Among 40 identified QTL for AA or AA-derived traits, three genomic regions were novel in terms of seed composition traits (oil, protein, and AA content). An additional 24 regions had previously not been specifically associated with the AA content.

CONCLUSIONS

Our results confirmed loci identified from previous studies but also suggested that network approaches for studying AA contents in soybean seed are valuable. Three genomic regions (Chr 5: 41,754,397-41,893,109 bp, Chr 9: 1,537,829-1,806,586 bp, and Chr 20: 31,554,795-33,678,257 bp) were significantly identified by all three approaches. Yet, the majority of associations between a genomic region and an AA trait were approach- and/or environment-specific. Using a combination of approaches provides insights into the genetic control and pleiotropy among AA contents, which can be applied to mechanistic understanding of variation in AA content as well as tailored nutrition in cultivars developed from soybean breeding programs.

Characteristic volatile compounds of white tea with different storage times using E-nose, HS-GC-IMS, and HS-SPME-GC-MS

This paper studied the influence of storage duration on the flavor profile of white tea in detail, with samples produced between 2020 and 2023. Sensory evaluation was performed by quantitative descriptive analysis (QDA), followed by an in-depth aroma components analysis employing an electronic nose (E-nose), headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS), and headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS). The QDA findings revealed a gradual transition in the flavor profile of white tea during storage, shifting from sweet, fruity, and floral to more herbal and stale characteristics. E-nose could well distinguish white tea with different storage times. A total of 55 and 53 volatile compounds were identified by HS-GC-IMS and HS-SPME-GC-MS, respectively. The orthogonal partial least squares-discriminant analysis models, based on HS-GC-IMS (R2Y = 0.998, Q2 = 0.987) and HS-SPME-GC-MS (R2Y = 0.984, Q2 = 0.993), successfully distinguished white tea samples stored for different storage times. Furthermore, 14 and 8 key compounds were screened based on the double variable criterion of one-way analysis of variance (p < 0.05) and variable importance in projection (VIP) >1.2, and their content changes were also compared. It is the gradual decrease of important aroma components such as 2-hexenal, 2-methyl-2-hepten-6-one, linalool, and geraniol, which are positively correlated with sweet, fruity, and floral aromas, and the gradual increase of hexanoic acid, thiophene, propanoic acid, dimethyl disulfide, and borneyl acetate, which are positively correlated with herbal and stale flavor, that leads to the changes in flavor and aroma of white tea during storage. The results of the study provided a reference for elucidating the aroma characteristics of white tea at different storage times as well as a theoretical basis for the quality control of white tea.

Evaluation and identification of metabolites produced by Cytobacillus firmus in the interaction with Arabidopsis thaliana plants and their effect on Solanum lycopersicum

Currently, the use of bio-inputs is increasing due to the need to reduce the use of agrochemicals. However, one of the limitations is to preserve the viability of the living microorganisms, so it is important to find an alternative that allows us to obtain different metabolites to produce it. We evaluated three different interactions (contact, diffusible and volatile compounds) in vitro in Arabidopsis thaliana (At) seedlings with the strain Cytobacillus firmus M10 and its filtered secondary metabolites (M10F). The results showed that the seedlings inoculated by contact with the filtrate (AtM10F) presented increases in root length (30 %) and leaf area (33 %), as well as in the volatile interaction (At/M10F) with respect to the uninoculated treatment. For both interactions, the seedlings inoculated with the bacteria by contact (AtM10) and volatile (At/M10) obtained greater biomass (48 and 57 %). Subsequently, an evaluation at the end of the A. thaliana cycle showed that the treatments obtained by contact and distance when reinoculated with the bacteria and the filtrate (AtM10, At-M10 and AtM10F) obtained 50 % more seed yield than the control treatment, while AtM10F presented 72 %, while At/M10F presented the highest no. of siliques and seeds, which increased the yield by 65 %. In the Solanum lycopersicum (Sl) experiment, the filtrate (SlM10F) showed significant differences in seedling height, leaf length and width (23, 24 and 36 %, respectively). It also promoted an increase in fresh and dry weight, producing a greater root area and larger leaves compared to the control (Sl) and the bacteria (SlM10). We performed a qualitative characterization of the secondary metabolites present in the filtrate, where we found 2,4-DTBP, sylvopinol, isophthaladehyde, and eicosane of interest with possible growth-promoting effects on A. thaliana and tomato. We identified volatile compounds present in plant-microorganism and plant-filtrate interactions as possible precursors in the induction of plant growth, among which phenols, alcohols, aldehydes, alkanes, and alkenes stand out. Most of the analyzed compounds have not been found in the literature with reports of growth promoters, is important to mention that due to their characteristic functional groups they can derive and trigger the synthesis of new molecules with agronomic application.

Overexpression of EaALDH7, an aldehyde dehydrogenase gene from Erianthus arundinaceus enhances salinity tolerance in transgenic sugarcane (Saccharum spp. Hybrid)

Aldehyde Dehydrogenases (ALDH), a group of enzymes, are associated with the detoxification of aldehydes, produced in plants during abiotic stress conditions. Salinity remains a pivotal abiotic challenge that poses a significant threat to cultivation and yield of sugarcane. In this study, an Aldehyde dehydrogenase gene (EaALDH7) from Erianthus arundinaceus was overexpressed in the commercial sugarcane hybrid cultivar Co 86032. The transgenic lines were evaluated at different NaCl concentrations ranging from 0 mM to 200 mM for various morpho-physiological and biochemical parameters. The control plants, subjected to salinity stress condition, exhibited morphological changes in protoxylem, metaxylem, pericycle and pith whereas the transgenic events were on par with plants under regular irrigation. The overexpressing (OE) lines showed less cell membrane injury and improved photosynthetic rate, transpiration rate, and stomatal conductance than the untransformed control plants under stress conditions. Elevated proline content, higher activity of enzymatic antioxidants such as sodium dismutase (SOD), catalase (CAT), glutathione reductase (GR) and ascorbate peroxidase (APX) and low level of malondialdehyde MDA and hydrogen peroxide (H2O2) in the transgenic lines. The analysis of EaALDH7 expression revealed a significant upregulation in the transgenic lines compared to that of the untransformed control during salt stress conditions. The current study highlights the potentials of EaALDH7 gene in producing salinity-tolerant sugarcane cultivars.

Eryngial: An α,β-Unsaturated Fatty Aldehyde as the Major Phytotoxin in Spiny Coriander (Eryngium foetidum L.) Essential Oil

Weed species many times possess allelochemicals as a part of their survival strategy. These metabolites can be potential targets in search of natural phytotoxins. This study aims to evaluate the phytotoxic ability of fatty aldehyde-rich essential oil from spiny coriander (Eryngium foetidum) leaves, also known as fitweed or spiritweed and to further identify the active phytotoxins. This oil dose-dependently inhibited the wheatgrass coleoptile and radicle growth in multiple bioassays with half maximal inhibitory concentration (IC50) 30.6-56.7 μg/mL, while exhibiting a less pronounced effect on the germination (IC50 181.8 μg/mL). The phytotoxicity assessment of two oil constituents identified eryngial (trans-2-dodecenal), exclusively major fatty aldehydic constituent as the potent growth inhibitor with IC50 in the range 20.8-36.2 μg/mL during an early phase of wheatgrass emergence. Eryngial-inspired screening of eleven saturated fatty aldehydes and alcohols did not find a significantly higher phytotoxic potency. In an open vessel, eryngial as the supplementation in agar medium, dose-dependently inhibited the growth of pre-germinated seeds of one monocot (bermudagrass) and one dicot (green amaranth) weed species with IC50 in the range 23.8-65.4 μg/mL. The current study identified eryngial, an α,β-unsaturated fatty aldehyde of coriander origin to be a promising phytotoxic candidate for weed control.

Unraveling lipid peroxidation-mediated regulation of redox homeostasis for sustaining plant health

Lipid peroxidation (LPO) is a complex process that, depending on the context, can either result in oxidative injury or promote redox homeostasis. LPO is a series of reactions in which polyunsaturated fatty acids are attacked by free radicals that result in the synthesis of lipid peroxides. LPO can alter membrane fluidity and operation and produce secondary products that amplify oxidative stress. LPO can activate cellular signaling pathways that promote antioxidant defense mechanisms that provide oxidative stress protection by elevating antioxidant enzyme action potentials. Enzymatic and nonenzymatic mechanisms tightly regulate LPO to prevent excessive LPO and its adverse consequences. This article emphasizes the dual nature of LPO as a mechanism that can both damage cells and regulate redox homeostasis. In addition, it also highlights the major enzymatic and nonenzymatic mechanisms that tightly regulate LPO to prevent excessive oxidative damage. More importantly, it emphasizes the importance of understanding the cellular and biochemical complexity of LPO for developing strategies targeting this process for efficient management of plant stress.

Oxylipins and Reactive Carbonyls as Regulators of the Plant Redox and Reactive Oxygen Species Network under Stress

Reactive oxygen species (ROS), and in particular H2O2, serve as essential second messengers at low concentrations. However, excessive ROS accumulation leads to severe and irreversible cell damage. Hence, control of ROS levels is needed, especially under non-optimal growth conditions caused by abiotic or biotic stresses, which at least initially stimulate ROS synthesis. A complex network of thiol-sensitive proteins is instrumental in realizing tight ROS control; this is called the redox regulatory network. It consists of sensors, input elements, transmitters, and targets. Recent evidence revealed that the interplay of the redox network and oxylipins–molecules derived from oxygenation of polyunsaturated fatty acids, especially under high ROS levels–plays a decisive role in coupling ROS generation and subsequent stress defense signaling pathways in plants. This review aims to provide a broad overview of the current knowledge on the interaction of distinct oxylipins generated enzymatically (12-OPDA, 4-HNE, phytoprostanes) or non-enzymatically (MDA, acrolein) and components of the redox network. Further, recent findings on the contribution of oxylipins to environmental acclimatization will be discussed using flooding, herbivory, and establishment of thermotolerance as prime examples of relevant biotic and abiotic stresses.