RESUMO
Stylo (Stylosanthes guianensis) is a tropical legume known for its exceptional tolerance to low phosphate (Pi), a trait believed to be linked to its high acid phosphatase (APase) activity. Previous studies have observed genotypic variations in APase activity in stylo; however, the gene encoding the crucial APase responsible for this variation remains unidentified. In this study, transcriptomic and proteomic analyses were employed to identify eight Pi starvation-inducible (PSI) APases belonging to the purple APase (PAP) family in the roots of stylo and seven in the leaves. Among these PSI-PAPs, SgPAP7 exhibited a significantly positive correlation in its expression levels with the activities of both internal APase and root-associated APase across 20 stylo genotypes under low-Pi conditions. Furthermore, the recombinant SgPAP7 displayed high catalytic activity toward adenosine 5'-diphosphate (ADP) and phosphoenolpyruvate (PEP) in vitro. Overexpression (OE) of SgPAP7 in Arabidopsis facilitated exogenous organic phosphorus utilization. Moreover, SgPAP7 OE lines showed lower shoot ADP and PEP levels than the wild type, implying that SgPAP7 is involved in the catabolism and recycling of endogenous ADP and PEP, which could be beneficial for plant growth in low-Pi soils. In conclusion, SgPAP7 is a key gene with a major role in stylo adaptation to low-Pi conditions by facilitating the utilization of both exogenous and endogenous organic phosphorus sources. It may also function as a PEP phosphatase involved in a glycolytic bypass pathway that minimizes the need for adenylates and Pi. Thus, SgPAP7 could be a promising target for improving tolerance of crops to low-Pi availability.
Assuntos
Arabidopsis , Fabaceae , Fabaceae/genética , Fabaceae/metabolismo , Multiômica , Proteômica , Fósforo/metabolismo , Verduras/metabolismo , Fosfatase Ácida/genética , Fosfatase Ácida/metabolismo , Arabidopsis/genética , Raízes de Plantas/genética , Raízes de Plantas/metabolismo , Regulação da Expressão Gênica de PlantasRESUMO
Pigeonpea is the main protein source for more than one billion people, and it shows a strong adaptation to biotic stress and abiotic stress. Gene duplication is a fundamental process in genome evolution. Although the draft sequence of the pigeonpea genome has been available since 2011, further analysis of tandem duplicated genes (TDGs) and their contribution to the evolution of pigeonpea has not been reported. In this study, we identify 3211 TDGs in the pigeonpea genome and KEGG enrichment analysis of these genes shows that the TDGs are significantly enriched in resistance-related pathways. In addition, we find that TDGs are more abundant in retrotransposon-related genes in pigeonpea than in the other species included in our study. These results indicate that stress resistance in pigeonpea may be ascribed to resistance-related pathways and retrotransposons originating from tandem duplications. Our study will provide an important basis for further research in pigeonpea breeding.
Assuntos
Cajanus/genética , Duplicação Gênica , Estresse Fisiológico , Cajanus/metabolismo , Genoma de PlantaRESUMO
Colletotrichum, a hemibiotrophic fungal pathogen with a broad host range, causes a yield-limiting disease called anthracnose. Stylo (Stylosanthes) is a dominant pasture legume in tropics and subtropics, and anthracnose is one of its most destructive disease. Resistance mechanisms against anthracnose in stylo are poorly understood, thus hindering the development of resistant varieties. We performed time-resolved leaf transcriptomics, metabolomics and in vitro inhibition assay to investigate the defense responses against Colletotrichum gloeosporioides in stylo. Transcriptomics demonstrated that flavonoid biosynthetic genes were significantly induced during the infection. Consistently, metabolomics also showed the increased accumulation of flavonoid compounds. In vitro assays showed that phloretin and naringenin inhibited the mycelial growth, and apigenin, daidzein, quercetin and kaempferol suppressed conidial germination of Colletotrichum strains. Together, our results suggest that stylo plants cope with C. gloeosporioides by up-regulation of genes and compounds in flavonoid biosynthesis pathway, providing potential targets for resistance breeding.
Assuntos
Colletotrichum , Fabaceae , Colletotrichum/genética , Fabaceae/genética , Fabaceae/microbiologia , Flavonoides/farmacologia , Metabolômica , Melhoramento Vegetal , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , TranscriptomaRESUMO
BACKGROUND: As a heavy metal, manganese (Mn) can be toxic to plants. Stylo (Stylosanthes) is an important tropical legume that exhibits tolerance to high levels of Mn. However, little is known about the adaptive responses of stylo to Mn toxicity. Thus, this study integrated both physiological and transcriptomic analyses of stylo subjected to Mn toxicity. RESULTS: Results showed that excess Mn treatments increased malondialdehyde (MDA) levels in leaves of stylo, resulting in the reduction of leaf chlorophyll concentrations and plant dry weight. In contrast, the activities of enzymes, such as peroxidase (POD), phenylalanine ammonia-lyase (PAL) and polyphenol oxidase (PPO), were significantly increased in stylo leaves upon treatment with increasing Mn levels, particularly Mn levels greater than 400 µM. Transcriptome analysis revealed 2471 up-regulated and 1623 down-regulated genes in stylo leaves subjected to Mn toxicity. Among them, a set of excess Mn up-regulated genes, such as genes encoding PAL, cinnamyl-alcohol dehydrogenases (CADs), chalcone isomerase (CHI), chalcone synthase (CHS) and flavonol synthase (FLS), were enriched in secondary metabolic processes based on gene ontology (GO) analysis. Numerous genes associated with transcription factors (TFs), such as genes belonging to the C2H2 zinc finger transcription factor, WRKY and MYB families, were also regulated by Mn in stylo leaves. Furthermore, the C2H2 and MYB transcription factors were predicted to be involved in the transcriptional regulation of genes that participate in secondary metabolism in stylo during Mn exposure. Interestingly, the activation of secondary metabolism-related genes probably resulted in increased levels of secondary metabolites, including total phenols, flavonoids, tannins and anthocyanidins. CONCLUSIONS: Taken together, this study reveals the roles of secondary metabolism in the adaptive responses of stylo to Mn toxicity, which is probably regulated by specific transcription factors.
Assuntos
Fabaceae , Manganês , Fabaceae/genética , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Humanos , Manganês/toxicidade , Folhas de Planta , Metabolismo Secundário/genética , TranscriptomaRESUMO
BACKGROUND: Phosphorus (P) deficiency is one of the major constraints limiting plant growth, especially in acid soils. Stylosanthes (stylo) is a pioneer tropical legume with excellent adaptability to low P stress, but its underlying mechanisms remain largely unknown. RESULTS: In this study, the physiological, molecular and metabolic changes in stylo responding to phosphate (Pi) starvation were investigated. Under low P condition, the growth of stylo root was enhanced, which was attributed to the up-regulation of expansin genes participating in root growth. Metabolic profiling analysis showed that a total of 256 metabolites with differential accumulations were identified in stylo roots response to P deficiency, which mainly included flavonoids, sugars, nucleotides, amino acids, phenylpropanoids and phenylamides. P deficiency led to significant reduction in the accumulation of phosphorylated metabolites (e.g., P-containing sugars, nucleotides and cholines), suggesting that internal P utilization was enhanced in stylo roots subjected to low P stress. However, flavonoid metabolites, such as kaempferol, daidzein and their glycoside derivatives, were increased in P-deficient stylo roots. Furthermore, the qRT-PCR analysis showed that a set of genes involved in flavonoids synthesis were found to be up-regulated by Pi starvation in stylo roots. In addition, the abundances of phenolic acids and phenylamides were significantly increased in stylo roots during P deficiency. The increased accumulation of the metabolites in stylo roots, such as flavonoids, phenolic acids and phenylamides, might facilitate P solubilization and cooperate with beneficial microorganisms in rhizosphere, and thus contributing to P acquisition and utilization in stylo. CONCLUSIONS: These results suggest that stylo plants cope with P deficiency by modulating root morphology, scavenging internal Pi from phosphorylated metabolites and increasing accumulation of flavonoids, phenolic acids and phenylamides. This study provides valuable insights into the complex responses and adaptive mechanisms of stylo roots to P deficiency.
Assuntos
Fabaceae/metabolismo , Metaboloma , Compostos de Fósforo/metabolismo , Fósforo/deficiência , Raízes de Plantas/metabolismo , Fabaceae/genética , Expressão Gênica , Genes de Plantas , Solo/químicaRESUMO
BACKGROUND: Manganese (Mn), an essential element for plants, can be toxic when present in excess. Stylo (Stylosanthes) is a pioneer tropical legume with great potential for Mn tolerance, but its Mn tolerance mechanisms remain poorly understood. RESULTS: In this study, variations in Mn tolerance were observed among nine stylo genotypes. Stylo genotype 'RY5' exhibited the highest Mn tolerance compared to the other tested genotypes, whereas 'TF2001' was a Mn-sensitive genotype. The mechanisms underlying the response of stylo to Mn toxicity were further investigated using these two genotypes with contrasting Mn tolerance. Results showed that stylo genotype RY5 exhibited Mn tolerance superior to that of genotype TF2001, showing lower reductions in leaf chlorophyll concentration, chlorophyll fluorescence parameters, photosynthetic indexes and plant dry weight under Mn toxicity. A label-free quantitative proteomic analysis was conducted to investigate the protein profiles in the leaves and roots of RY5 in response to Mn toxicity. A total of 356 differentially expressed proteins (DEPs) were identified, including 206 proteins from leaves and 150 proteins from roots, which consisted of 71 upregulated, 62 downregulated, 127 strongly induced and 96 completely suppressed proteins. These DEPs were mainly involved in defense response, photosynthesis, carbon fixation, metabolism, cell wall modulation and signaling. The qRT-PCR analysis verified that 10 out of 12 corresponding gene transcription patterns correlated with their encoding proteins after Mn exposure. Finally, a schematic was constructed to reveal insights into the molecular processes in the leaves and roots of stylo in response to Mn toxicity. CONCLUSIONS: These findings suggest that stylo plants may cope with Mn toxicity by enhancing their defense response and phenylpropanoid pathways, adjusting photosynthesis and metabolic processes, and modulating protein synthesis and turnover. This study provides a platform for the future study of Mn tolerance mechanisms in stylo and may lead to a better understanding of the potential mechanisms underlying tropical legume adaptation to Mn toxicity.
Assuntos
Fabaceae/fisiologia , Manganês/toxicidade , Proteínas de Plantas/genética , Proteoma/genética , Fabaceae/genética , Genótipo , Proteínas de Plantas/metabolismo , Proteoma/metabolismoRESUMO
Manganese (Mn) is an essential element for plant growth due to its participation in a series of physiological and metabolic processes. Mn is also considered a heavy metal that causes phytotoxicity when present in excess, disrupting photosynthesis and enzyme activity in plants. Thus, Mn toxicity is a major constraint limiting plant growth and production, especially in acid soils. To cope with Mn toxicity, plants have evolved a wide range of adaptive strategies to improve their growth under this stress. Mn tolerance mechanisms include activation of the antioxidant system, regulation of Mn uptake and homeostasis, and compartmentalization of Mn into subcellular compartments (e.g., vacuoles, endoplasmic reticulum, Golgi apparatus, and cell walls). In this regard, numerous genes are involved in specific pathways controlling Mn detoxification. Here, we summarize the recent advances in the mechanisms of Mn toxicity tolerance in plants and highlight the roles of genes responsible for Mn uptake, translocation, and distribution, contributing to Mn detoxification. We hope this review will provide a comprehensive understanding of the adaptive strategies of plants to Mn toxicity through gene regulation, which will aid in breeding crop varieties with Mn tolerance via genetic improvement approaches, enhancing the yield and quality of crops.
Assuntos
Transporte Biológico/efeitos dos fármacos , Manganês/toxicidade , Metais Pesados/toxicidade , Plantas/genética , Antioxidantes/metabolismo , Parede Celular/efeitos dos fármacos , Parede Celular/genética , Homeostase/efeitos dos fármacos , Fotossíntese/efeitos dos fármacos , Plantas/efeitos dos fármacosRESUMO
As a major component of soil organic phosphorus (P), phytate-P is unavailable to plants unless hydrolysed by phytase to release inorganic phosphate. However, knowledge on natural variation in root-associated phytase activity and its underlying molecular mechanisms in plants remains fragmentary. In this study, variations in root internal and associated phytase activity were observed among 39 genotypes of Stylosanthes guianensis (Stylo), which is well adapted to acid soils. Furthermore, TPRC2001-1, the genotype with the highest root-associated phytase activity, was more capable of utilizing extracellular phytate-P than Fine-stem, the genotype with the lowest root-associated phytase activity. After protein liquid chromatography-tandem mass spectrometry analysis, a purple acid phosphatase (PAP), SgPAP23, was identified and cloned from TPRC2001-1. SgPAP23 exhibited high activity against phytate-P and was mainly localized on the plasma membrane. Furthermore, SgPAP23 overexpression resulted in significant increases of root-associated phytase activity and thus facilitated extracellular phytate-P utilization in both bean (Phaseolus vulgaris) hairy roots and Arabidopsis thaliana. The results herein support the conclusion that SgPAP23 is a primary contributor to the superior extracellular phytate-P utilization in stylo and thus is used to develop cultivars with efficient extracellular phytate-P utilization.
Assuntos
Fosfatase Ácida/metabolismo , Fabaceae/enzimologia , Ácido Fítico/metabolismo , Proteínas de Plantas/metabolismo , Raízes de Plantas/enzimologia , 6-Fitase/metabolismo , Arabidopsis , Cromatografia Líquida , Clonagem Molecular , Fabaceae/metabolismo , Raízes de Plantas/metabolismo , Plantas Geneticamente Modificadas , Reação em Cadeia da Polimerase em Tempo Real , Espectrometria de Massas em TandemRESUMO
Plant root cell walls are dynamic systems that serve as the first plant compartment responsive to soil conditions, such as phosphorus (P) deficiency. To date, evidence for the regulation of root cell wall proteins (CWPs) by P deficiency remains sparse. In order to gain a better understanding of the roles played by CWPs in the roots of soybean (Glycine max) in adaptation to P deficiency, we conducted an iTRAQ (isobaric tag for relative and absolute quantitation) proteomic analysis. A total of 53 CWPs with differential accumulation in response to P deficiency were identified. Subsequent qRT-PCR analysis correlated the accumulation of 21 of the 27 up-regulated proteins, and eight of the 26 down-regulated proteins with corresponding gene expression patterns in response to P deficiency. One up-regulated CWP, purple acid phosphatase 1-like (GmPAP1-like), was functionally characterized. Phaseolus vulgaris transgenic hairy roots overexpressing GmPAP1-like displayed an increase in root-associated acid phosphatase activity. In addition, relative growth and P content were significantly enhanced in GmPAP1-like overexpressing lines compared to control lines when deoxy-ribonucleotide triphosphate (dNTP) was applied as the sole external P source. Taken together, the results suggest that the modulation of CWPs may regulate complex changes in the root system in response to P deficiency, and that the cell wall-localized GmPAP1-like protein is involved in extracellular dNTP utilization in soybean.
Assuntos
Glycine max/genética , Proteínas de Plantas/genética , Polifosfatos/metabolismo , Fatores de Transcrição/genética , Parede Celular/metabolismo , Phaseolus/genética , Phaseolus/metabolismo , Proteínas de Plantas/metabolismo , Raízes de Plantas/genética , Raízes de Plantas/metabolismo , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Proteômica , Glycine max/metabolismo , Fatores de Transcrição/metabolismoRESUMO
Manganese (Mn) toxicity is a major constraint limiting plant growth on acidic soils. Superior Mn tolerance in Stylosanthes spp. has been well documented, but its molecular mechanisms remain largely unknown. In this study, superior Mn tolerance in Stylosanthes guianensis was confirmed, as reflected by a high Mn toxicity threshold. Furthermore, genetic variation of Mn tolerance was evaluated using two S. guianensis genotypes, which revealed that the Fine-stem genotype had higher Mn tolerance than the TPRC2001-1 genotype, as exhibited through less reduction in dry weight under excess Mn, and accompanied by lower internal Mn concentrations. Interestingly, Mn-stimulated increases in malate concentrations and exudation rates were observed only in the Fine-stem genotype. Proteomic analysis of Fine-stem roots revealed that S. guianensis Malate Dehydrogenase1 (SgMDH1) accumulated in response to Mn toxicity. Western-blot and quantitative PCR analyses showed that Mn toxicity resulted in increased SgMDH1 accumulation only in Fine-stem roots, but not in TPRC2001-1. The function of SgMDH1-mediated malate synthesis was verified through in vitro biochemical analysis of SgMDH1 activities against oxaloacetate, as well as in vivo increased malate concentrations in yeast (Saccharomyces cerevisiae), soybean (Glycine max) hairy roots, and Arabidopsis (Arabidopsis thaliana) with SgMDH1 overexpression. Furthermore, SgMDH1 overexpression conferred Mn tolerance in Arabidopsis, which was accompanied by increased malate exudation and reduced plant Mn concentrations, suggesting that secreted malate could alleviate Mn toxicity in plants. Taken together, we conclude that the superior Mn tolerance of S. guianensis is achieved by coordination of internal and external Mn detoxification through malate synthesis and exudation, which is regulated by SgMDH1 at both transcription and protein levels.
Assuntos
Fabaceae/fisiologia , Malato Desidrogenase/fisiologia , Malatos/metabolismo , Manganês/toxicidade , Adaptação Fisiológica/fisiologia , Fabaceae/enzimologia , Fabaceae/metabolismo , Malato Desidrogenase/efeitos dos fármacos , Doenças das Plantas/induzido quimicamente , Raízes de Plantas/metabolismo , Raízes de Plantas/fisiologia , ProteômicaRESUMO
Stylo (Stylosanthes spp.) is a pasture legume predominant in tropical and subtropical areas, where low phosphorus (P) availability is a major constraint for plant growth. Therefore, stylo might exhibit superior utilization of the P pool on acid soils, particularly organic P. However, little is known about mechanisms of inorganic phosphate (Pi) acquisition employed by stylo. In this study, the utilization of extracellular deoxy-ribonucleotide triphosphate (dNTP) and the underlying physiological and molecular mechanisms were examined for two stylo genotypes with contrasting P efficiency. Results showed that the P-efficient genotype, TPRC2001-1, was superior to the P-inefficient genotype, Fine-stem, when using dNTP as the sole P source. This was reflected by a higher dry weight and total P content for TPRC2001-1 than for Fine-stem, which was correlated with higher root-associated acid phosphatase (APase) activities in TPRC2001-1 under low P conditions. Subsequently, three PAP members were cloned from TPRC2001-1: SgPAP7, SgPAP10, and SgPAP26 Expression levels of these three SgPAPs were up-regulated by Pi starvation in stylo roots. Furthermore, there was a higher abundance of transcripts of SgPAP7 and SgPAP10 in TPRC2001-1 than in Fine-stem. Subcellular localization analysis demonstrated that these three SgPAPs were localized on the plasma membrane. Overexpression of these three SgPAPs could result in significantly increased root-associated APase activities, and thus extracellular dNTP utilization in bean hairy roots. Taken together, the results herein suggest that SgPAP7, SgPAP10, and SgPAP26 may differentially contribute to root-associated APase activities, and thus control extracellular dNTP utilization in stylo.
Assuntos
Fosfatase Ácida/metabolismo , Desoxirribonucleotídeos/metabolismo , Fabaceae/enzimologia , Glicoproteínas/metabolismo , Fosfatase Ácida/genética , Fosfatase Ácida/fisiologia , Fabaceae/genética , Fabaceae/metabolismo , Regulação da Expressão Gênica de Plantas/fisiologia , Genótipo , Glicoproteínas/genética , Glicoproteínas/fisiologia , Filogenia , Raízes de Plantas/enzimologia , Raízes de Plantas/metabolismoRESUMO
Stylosanthes (stylo) is a dominant leguminous forage in the tropics. Previous studies suggest that stylo has great potential for aluminium (Al) tolerance, but little is known about the underlying mechanism. A novel malic enzyme, SgME1, was identified from the Al-tolerant genotype TPRC2001-1 after 72 h Al exposure by two-dimensional electrophoresis, and the encoding gene was cloned and characterized via heterologous expression in yeast, Arabidopsis thaliana and bean (Phaseolus vulgaris) hairy roots. Internal Al detoxification might be mainly responsible for the 72 h Al tolerance of TPRC2001-1, as indicated by 5.8-fold higher root malate concentrations and approximately two-fold higher Al concentrations in roots and root symplasts of TPRC2001-1 than those of the Al-sensitive genotype Fine-stem. An accompanying increase in malate secretion might also reduce a fraction of Al uptake in TPRC2001-1. Gene and protein expression of SgME1 was only enhanced in TPRC2001-1 after 72 h Al exposure. Overexpressing SgME1 enhanced malate synthesis and rescued yeast, A. thaliana and bean hairy roots from Al toxicity via increasing intracellular malate concentrations and/or accompanied malate exudation. These results provide strong evidence that superior Al tolerance of stylo is mainly conferred by Al-enhanced malate synthesis, functionally controlled by SgME1.
Assuntos
Adaptação Fisiológica/efeitos dos fármacos , Alumínio/toxicidade , Fabaceae/enzimologia , Fabaceae/fisiologia , Malato Desidrogenase/metabolismo , Malatos/metabolismo , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Arabidopsis/fisiologia , Eletroforese em Gel Bidimensional , Fabaceae/efeitos dos fármacos , Fabaceae/genética , Genótipo , Malato Desidrogenase/isolamento & purificação , Oryza/efeitos dos fármacos , Oryza/fisiologia , Fenótipo , Exsudatos de Plantas/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento , Plantas Geneticamente Modificadas , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/fisiologiaRESUMO
Iron-doping modification is a prevailing approach for improving adsorption capability of biochar with environmental friendliness, but usually requires high temperature and suffers from iron aggregation. Herein, a highly adsorptive biochar was manufactured via sequential disperse impregnation of iron by refluxing and pyrolysis at low temperature for eliminating tetracycline (TC) from aqueous solution. Iron oxides and hydroxides were impregnated and stably dispersed on the carbon matrix as pyrolyzed at 200 °C, meanwhile abundant oxygen and nitrogen functional groups were generated on surface. The iron-doped biochar exhibited up to 891.37 mg/g adsorption capacity at pH 5, and could be recycled with high adsorption capability. The adsorption of TC should be mostly contributed to the hydrogen bonding of N/O functional groups and the hydrogen bonding/coordination of iron oxides/hydroxides. This would provide a valuable guide for dispersedly doping iron and conserving functional groups on biochar, and a super iron-doped biochar was prepared with superior recyclability.
Assuntos
Ferro , Poluentes Químicos da Água , Temperatura , Adsorção , Pirólise , Carvão Vegetal , Tetraciclina , Antibacterianos , Água , Hidróxidos , Poluentes Químicos da Água/análise , CinéticaRESUMO
BACKGROUND: Soybean (Glycine max) is a vital oil-producing crop. Augmenting oleic acid (OA) levels in soybean oil enhances its oxidative stability and health benefits, representing a key objective in soybean breeding. Pongamia (Pongamia pinnata), known for its abundant oil, OA, and flavonoid in the seeds, holds promise as a biofuel and medicinal plant. A comparative analysis of the lipid and flavonoid biosynthesis pathways in Pongamia and soybean seeds would facilitate the assessment of the potential value of Pongamia seeds and advance the genetic improvements of seed traits in both species. RESULTS: The study employed multi-omics analysis to systematically compare differences in metabolite accumulation and associated biosynthetic genes between Pongamia seeds and soybean seeds at the transcriptional, metabolic, and genomic levels. The results revealed that OA is the predominant free fatty acid in Pongamia seeds, being 8.3 times more abundant than in soybean seeds. Lipidomics unveiled a notably higher accumulation of triacylglycerols (TAGs) in Pongamia seeds compared to soybean seeds, with 23 TAG species containing OA. Subsequently, we identified orthologous groups (OGs) involved in lipid biosynthesis across 25 gene families in the genomes of Pongamia and soybean, and compared the expression levels of these OGs in the seeds of the two species. Among the OGs with expression levels in Pongamia seeds more than twice as high as in soybean seeds, we identified one fatty acyl-ACP thioesterase A (FATA) and two stearoyl-ACP desaturases (SADs), responsible for OA biosynthesis, along with two phospholipid:diacylglycerol acyltransferases (PDATs) and three acyl-CoA:diacylglycerol acyltransferases (DGATs), responsible for TAG biosynthesis. Furthermore, we observed a significantly higher content of the flavonoid formononetin in Pongamia seeds compared to soybean seeds, by over 2000-fold. This difference may be attributed to the tandem duplication expansions of 2,7,4'-trihydroxyisoflavanone 4'-O-methyltransferases (HI4'OMTs) in the Pongamia genome, which are responsible for the final step of formononetin biosynthesis, combined with their high expression levels in Pongamia seeds. CONCLUSIONS: This study extends beyond observations made in single-species research by offering novel insights into the molecular basis of differences in lipid and flavonoid biosynthetic pathways between Pongamia and soybean, from a cross-species comparative perspective.
RESUMO
Phosphorus (P) is one of the principal macronutrients for plant growth and productivity. Although the phosphate (Pi) transporter (PT) of the PHT1 family has been functionally characterized as participating in Pi uptake and transport in plants, information about PT genes in stylo (Stylosanthes guianensis), an important tropical forage legume that exhibits good adaptability to low-P acid soils, is limited. In this study, stylo root growth was found to be stimulated under P deficiency. The responses of PT genes to nutrient deficiencies and their roles in Pi uptake were further investigated in stylo. Four novel PT genes were identified in stylo and designated SgPT2 to SgPT5. Like SgPT1, which had been previously identified, all five SgPT proteins harboured the major facilitator superfamily (MFS) domain. Variations in tissue-specific expression were observed among the SgPT genes, which displayed diverse responses to deficiencies in nitrogen (N), P and potassium (K) in stylo roots. Four of the five SgPTs exhibited high levels of transcriptional responsiveness to P deficiency in roots. Furthermore, SgPT1, a Pi-starvation-induced gene closely related to legume PT homologues that participate in Pi transport, was selected for functional analysis. SgPT1 was localized to the plasma membrane. Analysis of transgenic Arabidopsis showed that overexpression of SgPT1 led to increased Pi accumulation and promoted root growth in Arabidopsis plants. Taken together, the results of this study suggest the involvement of SgPTs in the stylo response to nutrient deprivation. SgPT1 might mediate Pi uptake in stylo, which is beneficial for root growth during P deficiency.
Assuntos
Arabidopsis , Fabaceae , Fosfatos/metabolismo , Proteínas de Transporte de Fosfato/genética , Proteínas de Transporte de Fosfato/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Alanina Transaminase/genética , Alanina Transaminase/metabolismo , Fabaceae/genética , Fabaceae/metabolismo , Raízes de Plantas/genética , Raízes de Plantas/metabolismo , Regulação da Expressão Gênica de PlantasRESUMO
To develop a greener and more efficient method for producing cellulose nanofibers (CNFs) from raw plants, an AlCl3-enhanced ternary deep eutectic solvent, DES2 (consisting of choline chloride, citric acid, and AlCl3·6H2O in a molar ratio of 1:0.4:0.08), was synthesized. Raw elephant grass (EG) was pretreated with DES2, followed by sodium chlorite (NaClO2) bleaching and ultrasonic disruption to extract high-performance CNFs. The DES2 and NaClO2 treatments effectively removed hemicellulose and lignin, achieving removal rates of 99.23 % and 99.62 %, respectively, while maintaining a cellulose content of 78.3 %. DES2 demonstrated easy recyclability and maintained excellent biomass pretreatment performance even after multiple cycles. Following a brief 30-min intermittent ultrasound treatment, the resulting CNFs demonstrated superior crystallinity, increased carboxyl content, and a narrower width distribution compared to CNFs obtained from AlCl3-free DES1. Optimized conditions at 110 °C yielded CNFs with 85.3 % crystallinity, 0.64 mmol/g carboxyl content, 5.15 nm width distribution, and excellent dispersion in water for at least six months. Additionally, CNFs enhanced the tensile strength of chia seed mucilage (CM) composite films, showing a significant improvement to 26.6 MPa, representing a 231.3 % increase over the control film. This study offers a promising approach for efficiently producing CNFs from raw plants.
Assuntos
Celulose , Nanofibras , Solventes , Cloreto de Alumínio , Solventes Eutéticos ProfundosRESUMO
Stylo (Stylosanthes guianensis) is a tropical forage and cover crop that possesses low phosphate (Pi) tolerance traits. However, the mechanisms underlying its tolerance to low-Pi stress, particularly the role of root exudates, remain unclear. This study employed an integrated approach using physiological, biochemical, multi-omics, and gene function analyses to investigate the role of stylo root exudates in response to low-Pi stress. Widely targeted metabolomic analysis revealed that eight organic acids and one amino acid (L-cysteine) were significantly increased in the root exudates of Pi-deficient seedlings, among which tartaric acid and L-cysteine had strong abilities to dissolve insoluble-P. Furthermore, flavonoid-targeted metabolomic analysis identified 18 flavonoids that were significantly increased in root exudates under low-Pi conditions, mainly belonging to the isoflavonoid and flavanone subclasses. Additionally, transcriptomic analysis revealed that 15 genes encoding purple acid phosphatases (PAPs) had upregulated expression in roots under low-Pi conditions. Among them, SgPAP10 was characterized as a root-secreted phosphatase, and overexpression of SgPAP10 enhanced organic-P utilization by transgenic Arabidopsis. Overall, these findings provide detailed information regarding the importance of stylo root exudates in adaptation to low-Pi stress, highlighting the plant's ability to release Pi from organic-P and insoluble-P sources through root-secreted organic acids, amino acids, flavonoids, and PAPs.
Assuntos
Arabidopsis , Fabaceae , Fósforo/metabolismo , Cisteína/metabolismo , Multiômica , Raízes de Plantas/genética , Raízes de Plantas/metabolismo , Fabaceae/genética , Arabidopsis/genética , Arabidopsis/metabolismo , Exsudatos e TransudatosRESUMO
Malate dehydrogenase (MDH, EC 1.1.1.37) is a key enzyme that catalyzes a reversible NAD-dependent dehydrogenase reaction from oxaloacetate (OAA) to malate. Although MDH has been documented to participate in cellular metabolism and redox homeostasis in plants, the roles of MDH members in the tropical legume Stylosanthes guianensis (stylo) remain less definitive. In this study, except SgMDH1 that had been previously characterized, six novel MDH genes were isolated from stylo and were then designated as SgMDH2 to SgMDH7. All of the SgMDH proteins possessed the common features of NAD binding, dimerization interface and substrate binding sites. Expression analysis showed that three SgMDHs exhibited preferential expressions in leaves, and one SgMDH was mainly expressed in roots. Furthermore, SgMDHs were regulated by nutrient deficiencies in stylo roots, especially for phosphorus (-P) and potassium (-K) deficiencies. Differential responses of SgMDHs to trace metal stress and heavy metal toxicity were observed in stylo roots, suggesting the involvement of SgMDHs in the response of stylo to metal stresses. The six novel SgMDHs were subsequently expressed and purified from Escherichia coli to analyze their biochemical properties. Although SgMDHs exhibited variations in subcellular localizations, each SgMDH protein displayed a high level of catalytic efficiency towards OAA and NADH but a low level of catalytic efficiency towards malate and NAD+. In addition, the activities of recombinant SgMDH proteins were pH-dependent and temperature-sensitive, and exhibited differential regulations by various metal ions. These results together suggest the potential roles of SgMDHs in stylo coping with nutrient and metal stresses.
Assuntos
Fabaceae , Malato Desidrogenase , Malato Desidrogenase/genética , Malatos , NAD , Nutrientes , Raízes de PlantasRESUMO
Owing to their excellent characteristics, Pickering emulsions have been widely used in the development and the application of new carriers for embedding and for delivering active compounds. In this study, ß-carotene was successfully encapsulated in a Pickering emulsion stabilized using Desmodium intortum protein isolate (DIPI). The results showed that the encapsulation efficiencies of ß-carotene in the control group Tween 20 emulsion (TE) and the DIPI Pickering emulsion (DIPIPE) were 46.7 ± 2.5% and 97.3 ± 0.8%, respectively. After storage for 30 days at 25 °C and 37 °C in a dark environment, approximately 79.4% and 72.1% of ß-carotene in DIPIPE were retained. Compared with TE, DIPIPE can improve the stability of ß-carotene during storage. In vitro digestion experiments showed that the bioaccessibility rate of ß-carotene in DIPIPE was less than that in TE. Cytotoxicity experiments showed that DIPI and ß-carotene micelles within a specific concentration range exerted no toxic effects on 3T3 cells. These results indicate that DIPIPE can be used as a good food-grade carrier for embedding and transporting active substances to broaden the application of the protein-based Pickering emulsion system in the development of functional foods.
RESUMO
Phosphorus (P) is an essential macronutrient element for plant growth, and deficiency of inorganic phosphate (Pi) limits plant growth and yield. Elephant grass (Pennisetum purpureum) is an important fodder crop cultivated widely in tropical and subtropical areas throughout the world. However, the mechanisms underlying efficient P use in elephant grass under Pi deficiency remain poorly understood. In this study, the physiological and molecular responses of elephant grass leaves and roots to Pi deficiency were investigated. The results showed that dry weight, total P concentration, and P content decreased in Pi-deprived plants, but that acid phosphatase activity and P utilization efficiency (PUE) were higher than in Pi-sufficient plants. Regarding Pi starvation-responsive (PSR) genes, transcriptomics showed that 59 unigenes involved in Pi acquisition and transport (especially 18 purple acid phosphatase and 27 phosphate transporter 1 unigenes) and 51 phospholipase unigenes involved in phospholipids degradation or Pi-free lipids biosynthesis, as well as 47 core unigenes involved in the synthesis of phenylpropanoids and flavonoids, were significantly up-regulated by Pi deprivation in leaves or roots. Furthermore, 43 unigenes related to Pi-independent- or inorganic pyrophosphate (PPi)-dependent bypass reactions were markedly up-regulated in Pi-deficient leaves, especially five UDP-glucose pyrophosphorylase and 15 phosphoenolpyruvate carboxylase unigenes. Consistent with PSR unigene expression changes, metabolomics revealed that Pi deficiency significantly increased metabolites of Pi-free lipids, phenylpropanoids, and flavonoids in leaves and roots, but decreased phospholipid metabolites. This study reveals the mechanisms underlying the responses to Pi starvation in elephant grass leaves and roots, which provides candidate unigenes involved in efficient P use and theoretical references for the development of P-efficient elephant grass varieties.