Salicylic acid and jasmonic acid-mediated different fate of nickel phytoremediation in two populations of Alyssum inflatum Nyár.

This study investigates Ni phytoremediation and accumulation potential in the presence of salicylic acid (SA) (0, 50 and 200 µM) and jasmonic acid (JA) (0, 5 and 10 µM) in two populations of Alyssum inflatum under various nickel (Ni) doses (0, 100 and 400 µM). By measuring Ni levels in the shoots and roots, values of bioaccumulation coefficient (BAC), biological concentration factor (BCF) and translocation factor (TF) were calculated to quantify Ni accumulation and translocation between plant organs. Additionally, the amounts of histidine (His), citric acid (CA) and malic acid (MA) were explored. The results showed that plant dry weight (DW) [in shoot (29.8%, 8.74%) and in root (21.6%, 24.4%)] and chlorophyll [a (17.1%, 32.5%), b (10.1%, 30.9%)] declined in M and NM populations respectively, when exposed to Ni (400 µM). Conversely, the levels of MA [in shoot (37.0%, 32.0%) and in root (25.5%, 21.2%)], CA [in shoot (17.0%, 10.0%) and in root (47.9%, 37.2%)] and His [in shoot (by 1.59- and 1.34-fold) and in root (by 1.24- and 1.18-fold)] increased. Also, in the presence 400 µM Ni, the highest accumulation of Ni was observed in shoots of M (1392 µg/g DW) and NM (1382 µg/g DW). However, the application of SA and JA (especially in Ni 400 µM + SA 200 µM + JA 5 and 10 µM treatments) mitigated the harmful impact of Ni on physiological parameters. Also, a decreasing trend was observed in the contents of MA, CA, and His. The reduction of these compounds as important chelators of Ni caused a decrease in root-to-shoot Ni transfer and reducing accumulation in the shoots of both populations. The values of phytoremediation indices in both populations exposed to Ni (400 µM) were above one. In presence of the SA and JA, these indices showed a decreasing trend, although the values remained above one (BAC, BCF and TF > 1). Overall, the results indicated that SA and JA can reduce phytoremediation potential of the two populations through different mechanisms.

Parental conflict driven regulation of endosperm cellularization by a family of Auxin Response Factors.

The endosperm is a reproductive tissue supporting embryo development. In most flowering plants, the initial divisions of endosperm nuclei are not succeeded by cellularization; this process occurs only after a specific number of mitotic cycles have taken place. The timing of cellularization significantly influences seed viability and size. Previous research implicated auxin as a key factor in initiating nuclear divisions and determining the timing of cellularization. Here we uncover the involvement of a family of clustered auxin response factors (cARFs) as dosage-sensitive regulators of endosperm cellularization. cARFs, maternally expressed and paternally silenced, are shown to induce cellularization, thereby restricting seed growth. Our findings align with the predictions of the parental conflict theory, suggesting that cARFs represent major molecular targets in this conflict. We further demonstrate a recurring amplification of cARFs in the Brassicaceae, suggesting an evolutionary response to parental conflict by reinforcing maternal control over endosperm cellularization. Our study highlights that antagonistic parental control on endosperm cellularization converges on auxin biosynthesis and signalling.

Exploring the bioaccessibility of polyphenols and glucosinolates from Brassicaceae microgreens by combining metabolomics profiling and computational chemometrics.

Microgreens constitute natural-based foods with health-promoting properties mediated by the accumulation of glucosinolates (GLs) and phenolic compounds (PCs), although their bioaccessibility may limit their nutritional potential. This work subjected eight Brassicaceae microgreens to in vitro gastrointestinal digestion and large intestine fermentation before the metabolomics profiling of PCs and GLs. The application of multivariate statistics effectively discriminated among species and their interaction with in vitro digestion phases. The flavonoids associated with arugula and the aliphatic GLs related to red cabbage and cauliflower were identified as discriminant markers among microgreen species. The multi-omics integration along in vitro digestion and fermentation predicted bioaccessible markers, featuring potential candidates that may eventually be responsible for these functional foods' nutritional properties. This combined analytical and computational framework provided a promising platform to predict the nutritional metabolome-wide outcome of functional food consumption, as in the case of microgreens.

Myrosinase isogenes in wasabi (Wasabia japonica Matsum) and their putative roles in glucosinolate metabolism.

BACKGROUND: Wasabi, a Brassicaceae member, is well-known for its unique pungent and hot flavor which is produced from glucosinolate (GSL) degradation. Myrosinase (MYR) is a principle enzyme catalyzing the primary conversion of GSLs to GSL hydrolysis products (GHPs) which is responsible for plant defense system and food quality. Due to the limited information in relation to MYRs present in wasabi (Wasabia japonica M.), this study aimed to identify the MYR isogenes in W. japonica and analyze their roles in relation to GSL metabolism. RESULTS: In results, WjMYRI-1 was abundantly expressed in all organs, whereas WjMYRI-2 showed only trace expression levels. WjMYRII was highly expressed in the aboveground tissues. Interestingly, WjMYRII expression was significantly upregulated by certain abiotic factors, such as methyl jasmonate (more than 40-fold in petioles and 15-fold in leaves) and salt (tenfold in leaves). Young leaves and roots contained 97.89 and 91.17 µmol‧g-1 of GSL, whereas less GSL was produced in mature leaves and petioles (38.36 and 44.79 µmol‧g-1, respectively). Similar pattern was observed in the accumulation of GHPs in various plant organs. Notably, despite the non-significant changes in GSL production, abiotic factors treated samples enhanced significantly GHP content. Pearson's correlation analysis revealed that WjMYRI-1 expression significantly correlated with GSL accumulation and GHP formation, suggesting the primary role of WjMYRI-1-encoding putative protein in GSL degradation. In contrast, WjMYRII expression level showed no correlation with GSL or GHP content, suggesting another physiological role of WjMYRII in stress-induced response. CONCLUSIONS: In conclusions, three potential isogenes (WjMYRI-1, WjMYRI-2, and WjMYRII) encoding for different MYR isoforms in W. japonica were identified. Our results provided new insights related to MYR and GSL metabolism which are important for the implications of wasabi in agriculture, food and pharmaceutical industry. Particularly, WjMYRI-1 may be primarily responsible for GSL degradation, whereas WjMYRII (clade II) may be involved in other regulatory pathways induced by abiotic factors.

Systematic characterization of CsbZIP transcription factors in Camelina sativa and functional analysis of CsbZIP-A12 mediating regulation of unsaturated fatty acid-enriched oil biosynthesis.

The basic leucine zipper (bZIP) transcription factors (TFs) function importantly in numerous life processes in plants. However, bZIP members and their biological roles remain unknown in Camelina sativa, a worldwide promising oil crop. Here, 220 CsbZIP proteins were identified in camelina and classified into thirteen groups. Two and 347 pairs of tandem and segmental duplication genes were detected to be underwent purification selection, with segmental duplication as the main driven-force of CsbZIP gene family expansion. Most CsbZIP genes displayed a tissue-specific expression pattern. Particularly, CsbZIP-A12 significantly positively correlated with many FA/oil biosynthesis-related genes, indicating CsbZIP-A12 may regulate lipid biosynthesis. Notably, yeast one-hybrid (Y1H), ß-Glucuronidase (GUS), dual-luciferase (LUC) and EMSA assays evidenced that CsbZIP-A12 located in nucleus interacted with the promoters of CsSAD2-3 and CsFAD3-3 genes responsible for unsaturated fatty acid (UFA) synthesis, thus activating their transcriptions. Overexpression of CsbZIP-A12 led to an increase of total lipid by 3.275 % compared to the control, followed with oleic and α-linolenic acid levels enhanced by 3.4 % and 5.195 %, and up-regulated the expressions of CsSAD2-3, CsFAD3-3 and CsPDAT2-3 in camelina seeds. Furthermore, heterogeneous expression of CsbZIP-A12 significantly up-regulated the expressions of NtSAD2, NtFAD3 and NtPDAT genes in tobacco plants, thereby improving the levels of total lipids and UFAs in both leaves and seeds without negative effects on other agronomic traits. Together, our findings suggest that CsbZIP-A12 upregulates FA/oil biosynthesis by activating CsSAD2-3 and CsFAD3-3 as well as possible other related genes. These data lay a foundation for further functional analyses of CsbZIPs, providing new insights into the TF-based lipid metabolic engineering to increase vegetable oil yield and health-beneficial quality in oilseeds.

Characterization of unique EDTA-insensitive methylthioalkylmalate synthase from Eutrema japonicum and its potential application in synthetic biology.

6-(Methylsulfinyl)hexyl isothiocyanate (6-MSITC), a derivative of glucosinolate with a six-carbon chain, is a compound found in wasabi and has diverse health-promoting properties. The biosynthesis of glucosinolates from methionine depends on a crucial step catalyzed methylthioalkylmalate synthases (MAMs), which are responsible for the generation of glucosinolates with varying chain lengths. In this study, our primary focus was the characterization of two methylthioalkyl malate synthases, MAM1-1 and MAM1-2, derived from Eutrema japonicum, commonly referred to as Japanese wasabi. Eutremajaponicum MAMs (EjMAMs) were expressed in an Escherichiacoli expression system, subsequently purified, and in vitro enzymatic activity was assayed. We explored the kinetic properties, optimal pH conditions, and cofactor preferences of EjMAMs and compared them with those of previously documented MAMs. Surprisingly, EjMAM1-2, categorized as a metallolyase family enzyme, displayed 20% of its maximum activity even in the absence of divalent metal cofactors or under high concentrations of EDTA. Additionally, we utilized AlphaFold2 to generate structural homology models of EjMAMs, and used in silico analysis and mutagenesis studies to investigate the key residues participating in catalytic activity. Moreover, we examined in vivo biosynthesis in E. coli containing Arabidopsis thaliana branched-chain amino acid transferase 3 (AtBCAT3) along with AtMAMs or EjMAMs and demonstrated that EjMAM1-2 exhibited the highest conversion rate among those MAMs, converting l-methionine to 2-(2-methylthio) ethyl malate (2-(2-MT)EM). EjMAM1-2 shows a unique property in vitro and highest activity on converting l-methionine to 2-(2-MT)EM in vivo which displays high potential for isothiocyanate biosynthesis in E. coli platform.

Synergistic interplay between melatonin and hydrogen sulfide enhances cadmium-induced oxidative stress resistance in stock (Matthiola incana L.).

Ornamental crops particularly cut flowers are considered sensitive to heavy metals (HMs) induced oxidative stress condition. Melatonin (MLT) is a versatile phytohormone with the ability to mitigate abiotic stresses induced oxidative stress in plants. Similarly, signaling molecules such as hydrogen sulfide (H2S) have emerged as potential options for resolving HMs related problems in plants. The mechanisms underlying the combined application of MLT and H2S are not yet explored. Therefore, we evaluated the ability of individual and combined applications of MLT (100 µM) and H2S in the form of sodium hydrosulfide (NaHS), a donor of H2S, (1.5 mM) to alleviate cadmium (Cd) stress (50 mg L-1) in stock (Matthiola incana L.) plants by measuring various morpho-physiological and biochemical characteristics. The results depicted that Cd-stress inhibited growth, photosynthesis and induced Cd-associated oxidative stress as depicted by excessive ROS accumulation. Combined application of MLT and H2S efficiently recovered all these attributes. Furthermore, Cd stress-induced oxidative stress markers including electrolyte leakage, malondialdehyde, and hydrogen peroxide are partially reversed in Cd-stressed plants by MLT and H2S application. This might be attributed to MLT or H2S induced antioxidant plant defense activities, which effectively reduce the severity of oxidative stress indicators. Overall, MLT and H2S supplementation, favorably regulated Cd tolerance in stock; yet, the combined use had a greater effect on Cd tolerance than the independent application.

A High-Throughput Approach for Photosynthesis Studies in a Brassicaceae Panel.

The study of natural variations in photosynthesis in the Brassicaceae family offers the possibility of identifying mechanisms to enhance photosynthetic efficiency in crop plants. Indeed, this family, and particularly its tribe Brassiceae, has been shown to harbor species that have a higher-than-expected photosynthetic efficiency, possibly as a result of a complex evolutionary history. Over the past two decades, methods have been developed to measure photosynthetic efficiency based on chlorophyll fluorescence. Chlorophyll fluorescence measurements are performed with special cameras, such as the FluorCams, which can be included in robotic systems to create high-throughput phenotyping platforms. While these platforms have so far demonstrated high efficiency in measuring small model species like Arabidopsis thaliana, they have the drawback of limited adaptability to accommodate different plant sizes. As a result, the range of species that can be analyzed is restricted. This chapter presents our approach to analyze the photosynthetic parameters: ϕPSII and Fv/Fm for a panel of Brassicaceae species, including a high-photosynthesis species, Hirschfeldia incana, and the adaptations to the phenotyping platform that are required to accommodate this varied group of plants.

The dimorphic diaspore model Aethionema arabicum (Brassicaceae): Distinct molecular and morphological control of responses to parental and germination temperatures.

Plants in habitats with unpredictable conditions often have diversified bet-hedging strategies that ensure fitness over a wider range of variable environmental factors. A striking example is the diaspore (seed and fruit) heteromorphism that evolved to maximize species survival in Aethionema arabicum (Brassicaceae) in which external and endogenous triggers allow the production of two distinct diaspores on the same plant. Using this dimorphic diaspore model, we identified contrasting molecular, biophysical, and ecophysiological mechanisms in the germination responses to different temperatures of the mucilaginous seeds (M+ seed morphs), the dispersed indehiscent fruits (IND fruit morphs), and the bare non-mucilaginous M- seeds obtained by pericarp (fruit coat) removal from IND fruits. Large-scale comparative transcriptome and hormone analyses of M+ seeds, IND fruits, and M- seeds provided comprehensive datasets for their distinct thermal responses. Morph-specific differences in co-expressed gene modules in seeds, as well as in seed and pericarp hormone contents, identified a role of the IND pericarp in imposing coat dormancy by generating hypoxia affecting abscisic acid (ABA) sensitivity. This involved expression of morph-specific transcription factors, hypoxia response, and cell wall remodeling genes, as well as altered ABA metabolism, transport, and signaling. Parental temperature affected ABA contents and ABA-related gene expression and altered IND pericarp biomechanical properties. Elucidating the molecular framework underlying the diaspore heteromorphism can provide insight into developmental responses to globally changing temperatures.

Exo84c-regulated degradation is involved in the normal self-incompatible response in Brassicaceae.

The self-incompatibility system evolves in angiosperms to promote cross-pollination by rejecting self-pollination. Here, we show the involvement of Exo84c in the SI response of both Brassica napus and Arabidopsis. The expression of Exo84c is specifically elevated in stigma during the SI response. Knocking out Exo84c in B. napus and SI Arabidopsis partially breaks down the SI response. The SI response inhibits both the protein secretion in papillae and the recruitment of the exocyst complex to the pollen-pistil contact sites. Interestingly, these processes can be partially restored in exo84c SI Arabidopsis. After incompatible pollination, the turnover of the exocyst-labeled compartment is enhanced in papillae. However, this process is perturbed in exo84c SI Arabidopsis. Taken together, our results suggest that Exo84c regulates the exocyst complex vacuolar degradation during the SI response. This process is likely independent of the known SI pathway in Brassicaceae to secure the SI response.

Untargeted metabolomic analysis of the metabolites in roots of Pugionium cornutum seedlings under drought stress.

Pugionium cornutum is an annual or biennial xerophyte distributed in arid regions, with drought resistance properties. While previous studies have predominantly focused on the physiological changes of P. cornutum , the understanding of its metabolite variations remains limited. In this study, untargeted metabolomic technology was performed to analyse the change of metabolites in the roots of P. cornutum seedlings under drought stress. Our findings revealed that compared to the R1, the root water potential and the number of lateral roots increased, while the length of the tap root and fresh weight increased first and then decreased. In the R1-R2, a total of 45 differential metabolites (DMs) were identified, whereas in the R1-R3 82 DMs were observed. Subsequently, KEGG analysis revealed a significant enrichment of microbial metabolism in diverse environments and aminobenzoate degradation in the R1-R2, and phenylpropanoid biosynthesis, ubiquinone, and other terpenoid-quinone biosynthesis and isoquinoline alkaloid biosynthesis were significantly enriched in the R1-R3. The upregulation DMs, including L-arginosuccinate, L-tyrosine, p-coumarate, caffeate, ferulate, vanillin, coniferin, 5-aminopentanoate, 2-methylmaleate and 2-furoate in P. cornutum seedlings may play a crucial role in enhancing root growth and improving drought resistance. These findings provide a basis for future investigations into the underlying mechanisms of drought resistance in P. cornutum .

Different metabolic adaptation strategies after overwintering in Eutrema sp. and Arabidopsis accessions under field conditions in Germany.

Successful overwintering is a prerequisite for high fitness in temperate perennials and winter annuals and is highly dependent on increased freezing tolerance and timely balancing of deacclimation with growth resumption in spring. To assess fitness costs associated with overwintering and elucidate metabolic mechanisms underlying winter survival and the switch from acclimated freezing tolerance to growth resumption, we performed a comparative field study using 14 Eutrema salsugineum accessions, E. halophilum, E. botschantzevii and 11 Arabidopsis thaliana accessions differing in freezing tolerance. Winter survival and reproductive fitness parameters were recorded and correlated with phenological stage and metabolite status during growth resumption in spring. The results revealed considerable intraspecific variation in winter survival, but survival rates of the extremophyte Eutrema were not inherently better. In both Eutrema and A. thaliana, improved winter survival was associated with reduced reproductive fitness. Metabolic analysis by GC-MS revealed intrinsic differences in the primary metabolism of the two genera during deacclimation. Eutrema contained higher levels of several amino and chlorogenic acids, while Arabidopsis had higher levels of several sugars and sugar conjugates. In both genera, increased levels of several soluble sugars were associated with increased winter survival, whereas myo-inositol has different roles in overwintering of Eutrema and A. thaliana. In addition, differences in amino acid metabolism and polyhydroxy acids levels after winter survival were found. The results provide strong evidence for a trade-off between increased winter survival and reproductive fitness in both Eutrema and Arabidopsis and document inherent differences in their metabolic strategies to survive winter.

Specialized metabolite modifications in Brassicaceae seeds and plants: diversity, functions and related enzymes.

Covering: up to 2023Specialized metabolite (SM) modifications and/or decorations, corresponding to the addition or removal of functional groups (e.g. hydroxyl, methyl, glycosyl or acyl group) to SM structures, contribute to the huge diversity of structures, activities and functions of seed and plant SMs. This review summarizes available knowledge (up to 2023) on SM modifications in Brassicaceae and their contribution to SM plasticity. We give a comprehensive overview on enzymes involved in the addition or removal of these functional groups. Brassicaceae, including model (Arabidopsis thaliana) and crop (Brassica napus, Camelina sativa) plant species, present a large diversity of plant and seed SMs, which makes them valuable models to study SM modifications. In this review, particular attention is given to the environmental plasticity of SM and relative modification and/or decoration enzymes. Furthermore, a spotlight is given to SMs and related modification enzymes in seeds of Brassicaceae species. Seeds constitute a large reservoir of beneficial SMs and are one of the most important dietary sources, providing more than half of the world's intake of dietary proteins, oil and starch. The seed tissue- and stage-specific expressions of A. thaliana genes involved in SM modification are presented and discussed in the context of available literature. Given the major role in plant phytochemistry, biology and ecology, SM modifications constitute a subject of study contributing to the research and development in agroecology, pharmaceutical, cosmetics and food industrial sectors.

Overexpression of the Phosphatidylcholine:DiacylglycerolCholinephosphotransferase (PDCT) gene increases carbon flux toward triacylglycerol (TAG) synthesis in Camelinasativa seeds.

Camelinasativa has considerable promise as a dedicated industrial oilseed crop. Its oil-based blends have been tested and approved as liquid transportation fuels. Previously, we utilized metabolomic and transcriptomic profiling approaches and identified metabolic bottlenecks that control oil production and accumulation in seeds. Accordingly, we selected candidate genes for the metabolic engineering of Camelina. Here we targeted the overexpression of Camelina PDCT gene, which encodes the phosphatidylcholine: diacylglycerol cholinephosphotransferase enzyme. PDCT is proposed as a gatekeeper responsible for the interconversions of diacylglycerol (DAG) and phosphatidylcholine (PC) pools and has the potential to increase the levels of TAG in seeds. To confirm whether increased CsPDCT activity in developing Camelina seeds would enhance carbon flux toward increased levels of TAG and alter oil composition, we overexpressed the CsPDCT gene under the control of the seed-specific phaseolin promoter. Camelina transgenics exhibited significant increases in seed yield (19-56%), seed oil content (9-13%), oil yields per plant (32-76%), and altered polyunsaturated fatty acid (PUFA) content compared to their parental wild-type (WT) plants. Results from [14C] acetate labeling of Camelina developing embryos expressing CsPDCT in culture indicated increased rates of radiolabeled fatty acid incorporation into glycerolipids (up to 64%, 59%, and 43% higher in TAG, DAG, and PC, respectively), relative to WT embryos. We conclude that overexpression of PDCT appears to be a positive strategy to achieve a synergistic effect on the flux through the TAG synthesis pathway, thereby further increasing oil yields in Camelina.

Nudix hydrolase WvNUDX24 is involved in borneol biosynthesis in Wurfbainia villosa.

Borneol, camphor, and bornyl acetate are highly promising monoterpenoids widely used in medicine, flavor, food, and chemical applications. Bornyl diphosphate (BPP) serves as a common precursor for the biosynthesis of these monoterpenoids. Although bornyl diphosphate synthase (BPPS) that catalyzes the cyclization of geranyl diphosphate (GPP) to BPP has been identified in multiple plants, the enzyme responsible for the hydrolysis of BPP to produce borneol has not been reported. Here, we conducted in vitro and in vivo functional characterization to identify the Nudix hydrolase WvNUDX24 from W. villosa, which specifically catalyzes the hydrolysis of BPP to generate bornyl phosphate (BP), and then BP forms borneol under the action of phosphatase. Subcellular localization experiments indicated that the hydrolysis of BPP likely occurs in the cytoplasm. Furthermore, site-directed mutagenesis experiments revealed that four critical residues (R84, S96, P98, and G99) for the hydrolysis activity of WvNUDX24. Additionally, the functional identification of phosphatidic acid phosphatase (PAP) demonstrated that WvPAP5 and WvPAP10 were able to hydrolyze geranylgeranyl diphosphate (GGPP) and farnesyl diphosphate (FPP) to generate geranylgeranyl phosphate (GGP) and farnesyl phosphate (FP), respectively, but could not hydrolyze BPP, GPP, and neryl diphosphate (NPP) to produce corresponding monophosphate products. These findings highlight the essential role of WvNUDX24 in the first step of BPP hydrolysis to produce borneol and provide genetic elements for the production of BPP-related terpenoids through plant metabolic engineering and synthetic biology.

Transposable elements contribute to the establishment of the glycine shuttle in Brassicaceae species.

C3 -C4 intermediate photosynthesis has evolved at least five times convergently in the Brassicaceae, despite this family lacking bona fide C4 species. The establishment of this carbon concentrating mechanism is known to require a complex suite of ultrastructural modifications, as well as changes in spatial expression patterns, which are both thought to be underpinned by a reconfiguration of existing gene-regulatory networks. However, to date, the mechanisms which underpin the reconfiguration of these gene networks are largely unknown. In this study, we used a pan-genomic association approach to identify genomic features that could confer differential gene expression towards the C3 -C4 intermediate state by analysing eight C3 species and seven C3 -C4 species from five independent origins in the Brassicaceae. We found a strong correlation between transposable element (TE) insertions in cis-regulatory regions and C3 -C4 intermediacy. Specifically, our study revealed 113 gene models in which the presence of a TE within a gene correlates with C3 -C4 intermediate photosynthesis. In this set, genes involved in the photorespiratory glycine shuttle are enriched, including the glycine decarboxylase P-protein whose expression domain undergoes a spatial shift during the transition to C3 -C4 photosynthesis. When further interrogating this gene, we discovered independent TE insertions in its upstream region which we conclude to be responsible for causing the spatial shift in GLDP1 gene expression. Our findings hint at a pivotal role of TEs in the evolution of C3 -C4 intermediacy, especially in mediating differential spatial gene expression.

Intergrative metabolomic and transcriptomic analyses reveal the potential regulatory mechanism of unique dihydroxy fatty acid biosynthesis in the seeds of an industrial oilseed crop Orychophragmus violaceus.

BACKGROUND: Orychophragmus violaceus is a potentially important industrial oilseed crop due to the two 24-carbon dihydroxy fatty acids (diOH-FA) that was newly identified from its seed oil via a 'discontinuous elongation' process. Although many research efforts have focused on the diOH-FA biosynthesis mechanism and identified the potential co-expressed diacylglycerol acyltranferase (DGAT) gene associated with triacylglycerol (TAG)-polyestolides biosynthesis, the dynamics of metabolic changes during seed development of O. violaceus as well as its associated regulatory network changes are poorly understood. RESULTS: In this study, by combining metabolome and transcriptome analysis, we identified that 1,003 metabolites and 22,479 genes were active across four stages of seed development, which were further divided into three main clusters based on the patterns of metabolite accumulation and/or gene expression. Among which, cluster2 was mostly related to diOH-FA biosynthesis pathway. We thus further constructed transcription factor (TF)-structural genes regulatory map for the genes associated with the flavonoids, fatty acids and diOH-FA biosynthesis pathway in this cluster. In particular, several TF families such as bHLH, B3, HD-ZIP, MYB were found to potentially regulate the metabolism associated with the diOH-FA pathway. Among which, multiple candidate TFs with promising potential for increasing the diOH-FA content were identified, and we further traced the evolutionary history of these key genes among species of Brassicaceae. CONCLUSION: Taken together, our study provides new insight into the gene resources and potential relevant regulatory mechanisms of diOH-FA biosynthesis uniquely in seeds of O. violaceus, which will help to promote the downstream breeding efforts of this potential oilseed crop and advance the bio-lubricant industry.

Camelina sativa (L. Crantz) products; an alternative feed ingredient for poultry diets with its nutritional and physiological consequences.

Due to increased demand for common feedstuffs such as corn, soybean and fish meals for poultry diets, the search for alternative sources of energy and protein for feed production could help to reduce production costs in the commercial poultry industry. Camelina sativa might be considered a new source of protein, energy and n-3 fatty acids (FA) in poultry diets. The oil content of camelina seeds (CS) is about 35 to 40%. Approximately 50% of this oil is composed of polyunsaturated FA. Moreover, camelina meal (CM) has 16% crude fat. The major n-3 FA of CS and CM is α-linolenic acid (about 30%) which is considered to be nutritionally important. The oil contains other bio-active compounds such as γ-tocopherol, flavonoids and phenolic compounds. Camelina seeds and meal can produce 6258 and 5110 kcal/kg of gross energy, 245-292 and 315-398 g/kg crude protein and 248 and 127 g/kg crude fibre, respectively. However, CS and CM contain 21.77 and 28.08 µmol/g glucosinolates and 12.10 and 12.93 TIU /mg trypsin inhibitors, respectively as anti-nutritional factors (ANFs) that can affect poultry performance adversely. Overall, dietary inclusion of camelina products will supply energy and protein for bird, enhance the antioxidant capacity and lipid stability of poultry products and provide health-promoting n-3 FA and tocopherol rich-foods to humans. However, raw CS contains some ANFs, and its maximum safe level (MSL) is 5% meal or seed, and 2% oil for all type of birds. Hence, it is necessary to establish suitable techniques for removing anti-nutritional factors from CS and increase its MSL in poultry diets.

A radiation of Psylliodes flea beetles on Brassicaceae is associated with the evolution of specific detoxification enzymes.

Flea beetles of the genus Psylliodes have evolved specialized interactions with plant species belonging to several distantly related families, mainly Brassicaceae, Solanaceae, and Fagaceae. This diverse host use indicates that Psylliodes flea beetles are able to cope with different chemical defense metabolites, including glucosinolates, the characteristic defense metabolites of Brassicaceae. Here we investigated the evolution of host use and the emergence of a glucosinolate-specific detoxification mechanism in Psylliodes flea beetles. In phylogenetic analyses, Psylliodes species clustered into four major clades, three of which contained mainly species specialized on either Brassicaceae, Solanaceae, or Fagaceae. Most members of the fourth clade have broader host use, including Brassicaceae and Poaceae as major host plant families. Ancestral state reconstructions suggest that Psylliodes flea beetles were initially associated with Brassicaceae and then either shifted to Solanaceae or Fagaceae, or expanded their host repertoire to Poaceae. Despite a putative ancestral association with Brassicaceae, we found evidence that the evolution of glucosinolate-specific detoxification enzymes coincides with the radiation of Psylliodes on Brassicaceae, suggesting that these are not required for using Brassicaceae as hosts but could improve the efficiency of host use by specialized Psylliodes species.

13C-labeling reveals non-conventional pathways providing carbon for hydroxy fatty acid synthesis in Physaria fendleri.

Physaria fendleri is a member of the Brassicaceae that produces in its embryos hydroxy fatty acids, constituents of oils that are very valuable and widely used by industry for cosmetics, lubricants, biofuels, etc. Free of toxins and rich in hydroxy fatty acids, Physaria provides a promising alternative to imported castor oil and is on the verge of being commercialized. This study aims to identify important biochemical step(s) for oil synthesis in Physaria, which may serve as target(s) for future crop improvement. To advance towards this goal, the endosperm composition was analysed by LC-MS/MS to develop and validate culture conditions that mimic the development of the embryos in planta. Using developing Physaria embryos in culture and 13C-labeling, our studies revealed that: (i) Physaria embryos metabolize carbon into biomass with an efficiency significantly lower than other photosynthetic embryos; (ii) the plastidic malic enzyme provides 42% of the pyruvate used for de novo fatty acid synthesis, which is the highest measured so far in developing 'green' oilseed embryos; and (iii) Physaria uses non-conventional pathways to channel carbon into oil, namely the Rubisco shunt, which fixes CO2 released in the plastid, and the reversibility of isocitrate dehydrogenase, which provides additional carbon for fatty acid elongation.