RESUMEN
Plants release a wealth of metabolites into the rhizosphere that can shape the composition and activity of microbial communities in response to environmental stress. The connection between rhizodeposition and rhizosphere microbiome succession has been suggested, particularly under environmental stress conditions, yet definitive evidence is scarce. In this study, we investigated the relationship between rhizosphere chemistry, microbiome dynamics, and abiotic stress in the bioenergy crop switchgrass grown in a marginal soil under nutrient-limited, moisture-limited, and nitrogen (N)-replete, phosphorus (P)-replete, and NP-replete conditions. We combined 16S rRNA amplicon sequencing and LC-MS/MS-based metabolomics to link rhizosphere microbial communities and metabolites. We identified significant changes in rhizosphere metabolite profiles in response to abiotic stress and linked them to changes in microbial communities using network analysis. N-limitation amplified the abundance of aromatic acids, pentoses, and their derivatives in the rhizosphere, and their enhanced availability was linked to the abundance of bacterial lineages from Acidobacteria, Verrucomicrobia, Planctomycetes, and Alphaproteobacteria. Conversely, N-amended conditions increased the availability of N-rich rhizosphere compounds, which coincided with proliferation of Actinobacteria. Treatments with contrasting N availability differed greatly in the abundance of potential keystone metabolites; serotonin and ectoine were particularly abundant in N-replete soils, while chlorogenic, cinnamic, and glucuronic acids were enriched in N-limited soils. Serotonin, the keystone metabolite we identified with the largest number of links to microbial taxa, significantly affected root architecture and growth of rhizosphere microorganisms, highlighting its potential to shape microbial community and mediate rhizosphere plant-microbe interactions.
Asunto(s)
Metaboloma , Microbiota , Rizosfera , Microbiología del Suelo , Microbiota/fisiología , Nitrógeno/metabolismo , ARN Ribosómico 16S/genética , Nutrientes/metabolismo , Bacterias/metabolismo , Bacterias/clasificación , Bacterias/genética , Suelo/química , Fósforo/metabolismo , Raíces de Plantas/microbiología , Raíces de Plantas/metabolismo , Panicum/metabolismo , Panicum/microbiologíaRESUMEN
The heavy metal cadmium (Cd), known for its high toxicity, poses a grave threat to human health through the food chain. N6-methyladenosine (m6A), the most abundant internal modification, regulates plant adaptation to various adversities, yet the panorama of m6A modifications in switchgrass under cadmium stress remains elusive. This study examines the physiological responses of switchgrass roots and shoots exposed to 50 µM CdCl2, alongside an overview of transcriptome-wide m6A methylation patterns. After cadmium treatment, methylation modifications are primarily enriched near stop codons and the 3'UTR region, with a negative correlation between m6A modification and gene expression levels. In shoots, approximately 58 % of DEGs with m6A modifications show upregulation in expression and decrease in m6A peaks, including zinc transporter 4-like (ZIP4). In roots, about 43 % of DEGs with m6A modifications exhibit downregulation in expression and increase in m6A peaks, such as the ABC transporter family member (ABCG25). We further validate the m6A enrichment, gene expression and mRNA stability of ZIP4 in response to Cd treatment. The results suggest that the negative correlation of m6A enrichment and gene expression is due to altered mRNA stability. Our study establishes an m6A regulatory network governing cadmium transport in switchgrass roots and shoots, offering new avenues for candidate gene manipulation in phytoremediation applications of heavy metal pollution.
Asunto(s)
Cadmio , Regulación de la Expresión Génica de las Plantas , Panicum , Raíces de Plantas , Transcriptoma , Transcriptoma/efectos de los fármacos , Cadmio/toxicidad , Panicum/genética , Panicum/efectos de los fármacos , Panicum/metabolismo , Raíces de Plantas/efectos de los fármacos , Raíces de Plantas/metabolismo , Raíces de Plantas/genética , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Metilación , Adenosina/análogos & derivados , Adenosina/metabolismo , Estrés Fisiológico , Brotes de la Planta/efectos de los fármacos , Brotes de la Planta/metabolismo , Brotes de la Planta/genética , Redes Reguladoras de Genes/efectos de los fármacos , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismoRESUMEN
N6-methyladenosine (m6A), a nucleotide modification that is frequently seen in RNA, plays a crucial role in plant growth, development and stress resistance. However, the m6A regulatory machinery in switchgrass (Panicum virgatum L.), a model plant for cellulose-to-ethanol conversion, remains largely unknown. In this study, we identified 57 candidate genes involved in m6A-regulation in the switchgrass genome, and analyzed their chromosomal distribution, evolutionary relationships, and functions. Notably, we observed distinct gene expression patterns under salt and drought stress, with salt stress inducing writer and eraser genes, alongside drought stress predominantly affecting reader genes. Additionally, we knocked out PvALKBH10, an m6A demethylase gene, via CRISPR/Cas9 and found its potential function in controlling flowering time. This study provides insight into the genomic organization and evolutionary features of m6A-associated putative genes in switchgrass, and therefore serves as the basis for further functional studies.
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Flores , Regulación de la Expresión Génica de las Plantas , Panicum , Proteínas de Plantas , Panicum/genética , Panicum/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Flores/genética , Flores/crecimiento & desarrollo , Adenosina/análogos & derivados , Adenosina/metabolismo , Adenosina/genética , Genes de Plantas , Familia de MultigenesRESUMEN
Little millet (Panicum sumatrense Roth ex Roem. & Schult.) is an essential minor millet of southeast Asia and Africa's temperate and subtropical regions. The plant is stress-tolerant, has a short life cycle, and has a mineral-rich nutritional profile associated with unique health benefits. We report the developmental gene expression atlas of little millet (genotype JK-8) from ten tissues representing different stages of its life cycle, starting from seed germination and vegetative growth to panicle maturation. The developmental transcriptome atlas led to the identification of 342 827 transcripts. The BUSCO analysis and comparison with the transcriptomes of related species confirm that this study presents high-quality, in-depth coverage of the little millet transcriptome. In addition, the eFP browser generated here has a user-friendly interface, allowing interactive visualizations of tissue-specific gene expression. Using these data, we identified transcripts, the orthologs of which in Arabidopsis and rice are involved in nutrient acquisition, transport, and response pathways. The comparative analysis of the expression levels of these transcripts holds great potential for enhancing the mineral content in crops, particularly zinc and iron, to address the issue of "hidden hunger" and to attain nutritional security, making it a valuable asset for translational research.
Asunto(s)
Regulación de la Expresión Génica de las Plantas , Panicum , Transcriptoma , Transcriptoma/genética , Panicum/genética , Panicum/metabolismo , Panicum/crecimiento & desarrollo , Minerales/metabolismo , Grano Comestible/genética , Grano Comestible/crecimiento & desarrollo , Grano Comestible/metabolismo , Perfilación de la Expresión GénicaRESUMEN
Culm development in grasses can be controlled by both miR156 and cytokinin. However, the crosstalk between the miR156-SPL module and the cytokinin metabolic pathway remains largely unknown. Here, we found CYTOKININ OXIDASE/DEHYDROGENASE4 (PvCKX4) plays a negative regulatory role in culm development of the bioenergy grass Panicum virgatum (switchgrass). Overexpression of PvCKX4 in switchgrass reduced the internode diameter and length without affecting tiller number. Interestingly, we also found that PvCKX4 was always upregulated in miR156 overexpressing (miR156OE) transgenic switchgrass lines. Additionally, upregulation of either miR156 or PvCKX4 in switchgrass reduced the content of isopentenyl adenine (iP) without affecting trans-zeatin (tZ) accumulation. It is consistent with the evidence that the recombinant PvCKX4 protein exhibited much higher catalytic activity against iP than tZ in vitro. Furthermore, our results showed that miR156-targeted SPL2 bound directly to the promoter of PvCKX4 to repress its expression. Thus, alleviating the SPL2-mediated transcriptional repression of PvCKX4 through miR156 overexpression resulted in a significant increase in cytokinin degradation and impaired culm development in switchgrass. On the contrary, suppressing PvCKX4 in miR156OE transgenic plants restored iP content, internode diameter, and length to wild-type levels. Most strikingly, the double transgenic lines retained the same increased tiller numbers as the miR156OE transgenic line, which yielded more biomass than the wild type. These findings indicate that the miR156-SPL module can control culm development through transcriptional repression of PvCKX4 in switchgrass, which provides a promising target for precise design of shoot architecture to yield more biomass from grasses.
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Regulación de la Expresión Génica de las Plantas , MicroARNs , Oxidorreductasas , Panicum , Proteínas de Plantas , Citocininas/metabolismo , MicroARNs/genética , MicroARNs/metabolismo , Oxidorreductasas/genética , Oxidorreductasas/metabolismo , Panicum/genética , Panicum/crecimiento & desarrollo , Panicum/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Modificadas GenéticamenteRESUMEN
BACKGROUND: Switchgrass (Panicum virgatum L.) is a warm-season perennial (C4) grass identified as an important biofuel crop in the United States. It is well adapted to the marginal environment where heat and moisture stresses predominantly affect crop growth. However, the underlying molecular mechanisms associated with heat and drought stress tolerance still need to be fully understood in switchgrass. The methylation of H3K4 is often associated with transcriptional activation of genes, including stress-responsive. Therefore, this study aimed to analyze genome-wide histone H3K4-tri-methylation in switchgrass under heat, drought, and combined stress. RESULTS: In total, ~ 1.3 million H3K4me3 peaks were identified in this study using SICER. Among them, 7,342; 6,510; and 8,536 peaks responded under drought (DT), drought and heat (DTHT), and heat (HT) stresses, respectively. Most DT and DTHT peaks spanned 0 to + 2000 bases from the transcription start site [TSS]. By comparing differentially marked peaks with RNA-Seq data, we identified peaks associated with genes: 155 DT-responsive peaks with 118 DT-responsive genes, 121 DTHT-responsive peaks with 110 DTHT-responsive genes, and 175 HT-responsive peaks with 136 HT-responsive genes. We have identified various transcription factors involved in DT, DTHT, and HT stresses. Gene Ontology analysis using the AgriGO revealed that most genes belonged to biological processes. Most annotated peaks belonged to metabolite interconversion, RNA metabolism, transporter, protein modifying, defense/immunity, membrane traffic protein, transmembrane signal receptor, and transcriptional regulator protein families. Further, we identified significant peaks associated with TFs, hormones, signaling, fatty acid and carbohydrate metabolism, and secondary metabolites. qRT-PCR analysis revealed the relative expressions of six abiotic stress-responsive genes (transketolase, chromatin remodeling factor-CDH3, fatty-acid desaturase A, transmembrane protein 14C, beta-amylase 1, and integrase-type DNA binding protein genes) that were significantly (P < 0.05) marked during drought, heat, and combined stresses by comparing stress-induced against un-stressed and input controls. CONCLUSION: Our study provides a comprehensive and reproducible epigenomic analysis of drought, heat, and combined stress responses in switchgrass. Significant enrichment of H3K4me3 peaks downstream of the TSS of protein-coding genes was observed. In addition, the cost-effective experimental design, modified ChIP-Seq approach, and analyses presented here can serve as a prototype for other non-model plant species for conducting stress studies.
Asunto(s)
Panicum , Panicum/metabolismo , Calor , Lisina/metabolismo , Histonas/metabolismo , Sequías , Estrés Fisiológico/genética , Metilación , Regulación de la Expresión Génica de las Plantas , Perfilación de la Expresión GénicaRESUMEN
Applying extracts from plants is considered a safe approach in biomedicine and bio-nanotechnology. The present report is considered the first study that evaluated the seeds of Lasiurus scindicus and Panicum turgidum as biogenic agents in the synthesis of silver nanoparticles (AgNPs) which had bioactivity against cancer cells and bacteria. Assessment of NPs activity against varied cell lines (colorectal cancer HCT116 and breast cancer MDA MBA 231 and MCF 10A used as control) was performed beside the antibacterial efficiency. Different techniques (DLS, TEM, EDX and FTIR) were applied to characterize the biosynthesized AgNPs. The phytochemicals from both L. scindicus and Panicum turgidum were identified by GC-MS analysis. Spherical monodisperse NPs at average diameters of 149.6 and 100.4 nm were obtained from seed extract of L. scindicus (L-AgNPs) and P. turgidum, (P-AgNPs) respectively. A strong absorption peak at 3 keV is observed by the EDX spectrum in the tested NPs. Our study provided effective NPs in mitigating the tested cell lines and the lowest IC50 were 7.8 and 10.30 for MDA MB231 treated by L-AgNPs and P-AgNPs, respectively. Both fabricated NPs might differentially target the MDA MB231 cells compared to HCT116 and MCF10A. Ultrastructural changes and damage for the NPs-treated MDA MB231 cells were studied using TEM and LSM analysis. Antibacterial activity was also observed. About 200 compounds were identified in L. scindicus and P. turgidum by GC-MS analysis might be responsible for the NPs reduction and capping abilities. Efficient NPs against cancer cells and microbes were obtained, however large-scale screening is needed to validate our findings.
Asunto(s)
Nanopartículas del Metal , Panicum , Plata/química , Panicum/metabolismo , Nanopartículas del Metal/química , Extractos Vegetales/química , Antibacterianos/química , Semillas/metabolismo , Espectroscopía Infrarroja por Transformada de FourierRESUMEN
BACKGROUND: The small YABBY plant-specific transcription factor has a prominent role in regulating plant growth progress and responding to abiotic stress. RESULTS: Here, a total of 16 PvYABBYs from switchgrass (Panicum virgatum L.) were identified and classified into four distinct subgroups. Proteins within the same subgroup exhibited similar conserved motifs and gene structures. Synteny analyses indicated that segmental duplication contributed to the expansion of the YABBY gene family in switchgrass and that complex duplication events occurred in rice, maize, soybean, and sorghum. Promoter regions of PvYABBY genes contained numerous cis-elements related to stress responsiveness and plant hormones. Expression profile analysis indicated higher expression levels of many PvYABBY genes during inflorescence development and seed maturation, with lower expression levels during root growth. Real-time quantitative PCR analysis demonstrated the sensitivity of multiple YABBY genes to PEG, NaCl, ABA, and GA treatments. The overexpression of PvYABBY14 in Arabidopsis resulted in increased root length after treatment with GA and ABA compared to wild-type plants. CONCLUSIONS: Taken together, our study provides the first genome-wide overview of the YABBY transcription factor family, laying the groundwork for understanding the molecular basis and regulatory mechanisms of PvYABBY14 in response to ABA and GA responses in switchgrass.
Asunto(s)
Arabidopsis , Panicum , Panicum/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Reguladores del Crecimiento de las Plantas , Genes de Plantas , Estrés Fisiológico/genética , Factores de Transcripción/genética , Regulación de la Expresión Génica de las Plantas , Filogenia , Proteínas de Plantas/metabolismoRESUMEN
Switchgrass (Panicum virgatum L.) plays a pivotal role as a bioenergy feedstock in the production of cellulosic ethanol and contributes significantly to enhancing ecological grasslands and soil quality. The utilization of non-coding RNAs (ncRNAs) has gained momentum in deciphering the intricate genetic responses to abiotic stress in various plant species. Nevertheless, the current research landscape lacks a comprehensive exploration of the responses of diverse ncRNAs, including long non-coding RNAs (lncRNAs), circular RNAs (circRNAs), and microRNAs (miRNAs), to drought stress in switchgrass. In this study, we employed whole transcriptome sequencing to comprehensively characterize the expression profiles of both mRNA and ncRNAs during episodes of drought stress in switchgrass. Our analysis identified a total of 12,511 mRNAs, 59 miRNAs, 38 circRNAs, and 368 lncRNAs that exhibited significant differential expression between normal and drought-treated switchgrass leaves. Notably, the majority of up-regulated mRNAs displayed pronounced enrichment within the starch and sucrose metabolism pathway, as validated through KEGG analysis. Co-expression analysis illuminated that differentially expressed (DE) lncRNAs conceivably regulated 1308 protein-coding genes in trans and 7110 protein-coding genes in cis. Furthermore, both cis- and trans-target mRNAs of DE lncRNAs exhibited enrichment in four common KEGG pathways. The intricate interplay between lncRNAs and circRNAs with miRNAs via miRNA response elements was explored within the competitive endogenous RNA (ceRNA) network framework. As a result, we constructed elaborate regulatory networks, including lncRNA-novel_miRNA480-mRNA, lncRNA-novel_miRNA304-mRNA, lncRNA/circRNA-novel_miRNA122-PvSS4, and lncRNA/circRNA-novel_miRNA14-PvSS4, and subsequently validated the functionality of the target gene, starch synthase 4 (PvSS4). Furthermore, through the overexpression of PvSS4, we ascertained its capacity to enhance drought tolerance in yeast. However, it is noteworthy that PvSS4 did not exhibit any discernible impact under salt stress conditions. These findings, as presented herein, not only contribute substantively to our understanding of ceRNA networks but also offer a basis for further investigations into their potential functions in response to drought stress in switchgrass.
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MicroARNs , Panicum , ARN Largo no Codificante , ARN Mensajero/genética , ARN Mensajero/metabolismo , ARN Circular/genética , ARN Circular/metabolismo , Panicum/genética , Panicum/metabolismo , ARN Largo no Codificante/genética , Sequías , Perfilación de la Expresión Génica , MicroARNs/genética , MicroARNs/metabolismo , Redes Reguladoras de GenesRESUMEN
Wild panicgrass (Panicum miliaceum L. var. ruderale kit.) is an annual grass weed that primarily occurs in maize fields. Nicosulfuron is a widely used selective herbicide that effectively controls gramineous weeds in maize fields. However, owing to its long-term and extensive application, the control of P. miliaceum has been substantially reduced. The objective of this study was to determine the resistance pattern to ALS inhibitors in P. miliaceum and investigate the underlying resistance mechanisms. These are important for guiding the prevention and eradication of resistant weeds. Whole plant bioassays showed P. miliaceum had evolved high levels of resistance to nicosulfuron and multiple resistance to atrazine and mesotrione. The ALS gene sequence results indicated the absence of mutations in the resistant population. Additionally, there was no significant difference found in the inhibition rate of the ALS enzyme activity (I50) between the resistant and sensitive populations. Following the application of malathion the resistant P. miliaceum population became more sensitive to nicosulfuron. At 96 h after application of nicosulfuron, glutathione-S-transferase activity in the resistant population was significantly higher than that in the susceptible population. The study reveals that the main cause of resistance to ALS inhibitor herbicide in P. miliaceum is likely increased metabolism of herbicides. These findings may assist in devising effective strategies for preventing and eliminating resistant P. miliaceum.
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Acetolactato Sintasa , Herbicidas , Panicum , Panicum/metabolismo , Herbicidas/farmacología , Compuestos de Sulfonilurea/farmacología , Piridinas/farmacología , Zea mays , Resistencia a los Herbicidas/genética , Acetolactato Sintasa/metabolismo , Proteínas de Plantas/genéticaRESUMEN
Switchgrass is one of the most promising bioenergy crops and is generally cultivated in arid climates and poor soils. Heat shock transcription factors (Hsfs) are key regulators of plant responses to abiotic and biotic stressors. However, their role and mechanism of action in switchgrass have not been elucidated. Hence, this study aimed to identify the Hsf family in switchgrass and understand its functional role in heat stress signal transduction and heat tolerance by using bioinformatics and RT-PCR analysis. Forty-eight PvHsfs were identified and divided into three main classes based on their gene structure and phylogenetic relationships: HsfA, HsfB, and HsfC. The results of the bioinformatics analysis showed a DNA-binding domain (DBD) at the N-terminal in PvHsfs, and they were not evenly distributed on all chromosomes except for chromosomes 8 N and 8 K. Many cis-elements related to plant development, stress responses, and plant hormones were identified in the promoter sequence of each PvHsf. Segmental duplication is the primary force underlying Hsf family expansion in switchgrass. The results of the expression pattern of PvHsfs in response to heat stress showed that PvHsf03 and PvHsf25 might play critical roles in the early and late stages of switchgrass response to heat stress, respectively, and HsfB mainly showed a negative response to heat stress. Ectopic expression of PvHsf03 in Arabidopsis significantly increased the heat resistance of seedlings. Overall, our research lays a notable foundation for studying the regulatory network in response to deleterious environments and for further excavating tolerance genes in switchgrass.
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Panicum , Factores de Transcripción del Choque Térmico/genética , Factores de Transcripción del Choque Térmico/metabolismo , Panicum/metabolismo , Filogenia , Respuesta al Choque Térmico/genética , Reguladores del Crecimiento de las Plantas , Regulación de la Expresión Génica de las Plantas/genética , Proteínas de Plantas/metabolismoRESUMEN
This work aimed to investigate the hypoglycemic effects and underlying mechanism of whole grain proso millet (Panicum miliaceum L.; WPM) on type 2 diabetes mellitus (T2DM). The results showed that WPM supplementation significantly reduced fasting blood glucose (FBG) and serum lipid levels in T2DM mice induced by a high-fat diet (HFD) combined with streptozotocin (STZ), with improved glucose tolerance, liver and kidney injury, and insulin resistance. In addition, WPM significantly inhibited the expression of gluconeogenesis-related genes G6pase, Pepck, Foxo1, and Pgc-1α. Further study by miRNA high-throughput sequencing revealed that WPM supplementation mainly altered the liver miRNA expression profile of T2DM mice by increasing the expression of miR-144-3p_R-1 and miR-423-5p, reducing the expression of miR-22-5p_R-1 and miR-30a-3p. GO and KEGG analyses showed that the target genes of these miRNAs were mainly enriched in the PI3K/AKT signaling pathway. WPM supplementation significantly increased the level of PI3K, p-AKT, and GSK3ß in the liver of T2DM mice. Taken together, WPM exerts antidiabetic effects by improving the miRNA profile and activating the PI3K/AKT signaling pathway to inhibit gluconeogenesis. This study implies that PM can act as a dietary supplement to attenuate T2DM.
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Diabetes Mellitus Experimental , Diabetes Mellitus Tipo 2 , Hiperglucemia , MicroARNs , Panicum , Ratones , Animales , Panicum/metabolismo , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Diabetes Mellitus Experimental/tratamiento farmacológico , Diabetes Mellitus Experimental/genética , Diabetes Mellitus Experimental/metabolismo , Fosfatidilinositol 3-Quinasas/metabolismo , Granos Enteros , Hiperglucemia/tratamiento farmacológico , Hiperglucemia/genética , Hiperglucemia/metabolismo , Hígado/metabolismo , MicroARNs/genética , MicroARNs/metabolismo , Hipoglucemiantes/metabolismoRESUMEN
Proso millet flour (PMF) and starch (PMS) were subjected to heat-moisture treatment (HMT) at 25 % moisture content and 110 °C for 4 h. The effects of HMT on physicochemical and structural properties and in vitro digestibility of PMF and PMS were analyzed. After HMT, SEM showed aggregation and damage to the surface of starch granules, while CLSM showed proteins wrapped around the granules. The amylopectin chain length distribution (CLD) remained unchanged in PMF and PMS after HMT, indicating intact covalent bonds between glucose units. HMT decreased the swelling power, solubility, viscosity of the paste, and gelatinization enthalpy and increased the pasting temperature and gelatinization temperature of PMF and PMS. HMT changed the XRD pattern of PMF from A to A + V type starches, whereas that of PMS remained unchanged. FTIR study showed an increase in the degree of short-range molecular order of PMF and PMS after HMT. In vitro digestibility evaluation showed that the rapidly (RDS) and slowly digestible starch (SDS) contents of PMF and PMS increased, whereas the resistant starch (RS) content decreased after HMT. HMT flour and starch have suitable properties for use in a wide range of food products, from canned to frozen, as well as non-food products.
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Panicum , Almidón , Almidón/química , Harina , Panicum/metabolismo , Calor , AmilopectinaRESUMEN
KEY MESSAGE: PvLBD12 enhanced the salt tolerance by increasing proline accumulation, improving K+ accumulation, and decreasing reactive oxygen species level in switchgrass. Abiotic stresses are the serious factors which limit plant development and productivity and restrict the agricultural economy. It is important, therefore, to understand the mechanism of abiotic tolerance in plants. Lateral organ boundaries domain (LBD) proteins as plant-specific transcription factors play important function in plant lateral organ development, plant regeneration, and abiotic stress. In our study, we identify 69 LBD members from switchgrass genome-wide sequences and classify them based on their homology with LBD proteins in Arabidopsis. RT-qPCR showed that PvLBD genes had different expression patterns under abiotic stress conditions, indicating that they play important roles in various stress. PvLBD12 was selected as a candidate gene for further functional analysis because it had the highest expression level under salt stress. Overexpression of PvLBD12 enhanced salt tolerance by altering a wide range of physiological responses (like increased proline accumulation, reduced malondialdehyde production, improved K+ accumulation, and reduced Na+ absorption) in switchgrass. Some stress response genes such as proline biosynthesis gene PvP5CS1, vacuolar Na+(K+)/H+ antiporter gene PvNHX1, two key ROS-scavenging enzyme genes PvCAT and PvSOD were all upregulated in PvLBD12 overexpression lines. Taken together, PvLBD12 plays a pivotal role in response to salt stress by increasing proline accumulation, improving K+ accumulation, reducing Na+ absorption, and decreasing reactive oxygen species level. It will be better to understand the potential biological functions of LBD genes in other plants.
Asunto(s)
Arabidopsis , Panicum , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Panicum/genética , Panicum/metabolismo , Plantas Modificadas Genéticamente/genética , Plantas Modificadas Genéticamente/metabolismo , Tolerancia a la Sal/genética , Especies Reactivas de Oxígeno/metabolismo , Arabidopsis/metabolismo , Prolina/metabolismo , Estrés Fisiológico/genética , Regulación de la Expresión Génica de las Plantas , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismoRESUMEN
Understanding the effect of nitrogen fertilization on the quality of proso millet is key to expanding the use of this crop to address water scarcity and food security. Therefore, this study determined the impact of nitrogen fertilization on the proso millet quality. Nitrogen fertilization significantly increased the NR and GS activities and decreased the GBSSase activity, resulting in an increase in protein content and reduction in amylose content and L*, which decreased the appearance quality. Nitrogen fertilization increased the proportion of short amylopectin chains, resulting in a more disordered carbohydrate structure, and decreased the proportion of hydrophilic functional groups, contributing to an increase in setback viscosity and decrease in pasting temperature in the waxy (w139) variety. In contrast, the non-waxy (n297) variety exhibited a larger proportion of long amylopectin chains, lower ordered structure and hydrophobic functional groups after nitrogen fertilization, which strengthened the inter- and intramolecular forces of starch colloids.
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Amilopectina , Panicum , Panicum/química , Panicum/metabolismo , Fertilizantes , Nitrógeno/metabolismo , Ceras , Almidón/química , AmilosaRESUMEN
APX is a key antioxidant enzyme in higher plants, scavenging H2O2 with ascorbate in several cellular compartments. Here, we report the crystal structures of cytosolic ascorbate peroxidase from switchgrass (Panicum virgatum L., Pvi), a strategic feedstock plant with several end uses. The overall structure of PviAPX was similar to the structures of other APX family members, with a bound ascorbate molecule at the ɣ-heme edge pocket as in other APXs. Our results indicated that the H2O2-dependent oxidation of ascorbate displayed positive cooperativity. Significantly, our study suggested that PviAPX can oxidize a broad range of phenylpropanoids with δ-meso site in a rather similar efficiency, which reflects its role in the fortification of cell walls in response to insect feeding. Based on detailed structural and kinetic analyses and molecular docking, as well as that of closely related APX enzymes, the critical residues in each substrate-binding site of PviAPX are proposed. Taken together, these observations shed new light on the function and catalysis of PviAPX, and potentially benefit efforts improve plant health and biomass quality in bioenergy and forage crops.
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Panicum , Ascorbato Peroxidasas/metabolismo , Panicum/metabolismo , Simulación del Acoplamiento Molecular , Peróxido de Hidrógeno/metabolismo , Ácido Ascórbico/metabolismo , Plantas/metabolismoRESUMEN
Cadmium (Cd) is a persistent heavy metal that poses environmental and public health concerns. This study aimed to identify the potential biomarkers responsible for Cd tolerance and accumulation by investigating the response of the content of essential metal elements, transporter gene expression, and root exudates to Cd stress in broomcorn millet (Panicum miliaceum). A hydroponics experiment was conducted using two broomcorn millet cultivars with distinct Cd tolerance levels and accumulation phenotypes (Cd-tolerant and Cd-sensitive cultivars). Cd stress inhibited lateral root growth, especially in the Cd-sensitive cultivar. Furthermore, Cd accumulation was significantly greater in the Cd-tolerant cultivar than in the Cd-sensitive cultivar. Cd stress significantly inhibited the absorption of essential metal elements and significantly increased the calcium concentration. Differentially expressed genes involved in metal ion transport were identified via transcriptome analysis. Cd stress altered the composition of root exudates, thus increasing lipid species and decreasing alkaloid, lignan, sugar, and alcohol species. Moreover, Cd stress significantly reduced most alkaloid, organic acid, and phenolic acid exudates in the Cd-tolerant cultivar, while it increased most lipid and phenolic acid exudates in the Cd-sensitive cultivar. Some significantly changed root exudates (ferulic acid, O-coumaric acid, and spermine) are involved in the phenylalanine biosynthesis, and arginine and proline metabolic pathways, thus, may be potential biomarkers of Cd stress response. Overall, metal ion absorption and root exudates are critical for Cd tolerance and accumulation in broomcorn millet. These findings provide valuable insights into improving Cd phytoremediation by applying mineral elements or metabolites.
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Panicum , Contaminantes del Suelo , Cadmio/metabolismo , Panicum/metabolismo , Exudados y Transudados/metabolismo , Lípidos , Raíces de Plantas/metabolismo , Contaminantes del Suelo/análisisRESUMEN
Switchgrass (Panicum virgatum L.), the prime bioenergy feedstock crop, is one ideal candidate for phytoremediation of cadmium (Cd). The absorption of Cd imposes severe endoplasmic reticulum (ER)-stress in plants. ER chaperone binding proteins (BiPs) are important modulators in ER-stress responses. The objective of this study was to characterize one Cd-responsive BiP gene, PvBiP2, in switchgrass for its roles in Cd tolerance and plant growth. PvBiP2 was up-regulated by Cd and the ER-stress inducer, dithiothreitol (DTT) and could be trans-activated by one Cd-responsive heat shock transcription factor PvHsfA4. Overexpression of PvBiP2 in switchgrass significantly increased its plant growth with higher height, stem diameter, leaf width, internode length, and tiller numbers than those of the wildtype (WT) plants under non-stress conditions. After 30 days of Cd treatment, the PvBiP2 over-expression transgenic lines showed 40-45% higher dry biomass accumulation with net photosynthesis rate (Pn), but lower electrolyte leakage (EL), malondialdehyde (MDA), and glutathione (GSH) levels than WT. Moreover, over-expressing PvBiP2 led to â¼90-140% Cd accumulation in plants but 46-57% lower Cd translocation rates to shoots. Together, the PvHSFA4-PvBiP2 module acted as positive regulators in plant Cd tolerance, and over-expressing PvBiP2 promoted plant vegetative growth as well as Cd tolerance making it an ideal molecular target for genetic improvement in switchgrass in the future.
Asunto(s)
Cadmio , Panicum , Cadmio/toxicidad , Cadmio/metabolismo , Biomasa , Panicum/genética , Panicum/metabolismo , Plantas Modificadas Genéticamente/genética , Plantas Modificadas Genéticamente/metabolismo , Regulación de la Expresión Génica de las PlantasRESUMEN
Polycyclic aromatic hydrocarbons (PAHs), as priority organic pollutants, are capable of accumulation in plants. Phenanthrene (Phe) is one of the most abundant low-molecular-weight PAH in the environment which is commonly used as a model PAH in many phytoremediation studies and as a representative compound for all PAHs group. This paper highlights the uptake, translocation, and accumulation of Phe by growing proso millet (Panicum miliaceum L.) in a pot experiment, subjected to 500, 1000, 1500, and 2000 ppm of Phe treatment after 15 and 30 days. Phe naturally existed in P. miliaceum and its concentration showed a time-dependent reduction in treated plant tissues as well as in perlites. Phe concentration in shoots was higher than in roots. During the aging process, the uptake of Phe was diminished whereas translocation factor (TF) demonstrated an overall increasing trend among treatments. The shoot concentration factor (SCF) values were higher than those of root concentration factor (RCF) on both days 15 and 30 and the highest values for both parameters were achieved in 500 ppm of Phe. Both RCFs and SCFs generally tended to decrease with the increase of perlite Phe concentrations. These results suggested that Phe tended to transfer to the shoots and be metabolized there. The Phe concentration revealed a significant decline in all levels of treatment on both 15 (84 to 96%) and 30 (76 to 94%) days. Therefore, the presence of P. miliaceum was effective in promoting the phytoremediation of Phe polluted perlites.
Asunto(s)
Panicum , Fenantrenos , Hidrocarburos Policíclicos Aromáticos , Panicum/metabolismo , Fenantrenos/metabolismo , Hidrocarburos Policíclicos Aromáticos/metabolismo , Transporte BiológicoRESUMEN
In proso millet, in certain circumstances, drought stress greatly influences growth and metabolisms. Thus, the present study was aimed to examine morphological, biochemical and ROS mechanisms between plant and drought stress in Panicum miliaceum L. To create the drought condition, water irrigation was done at different time intervals including 4, 7, 10, 13 days and control. All the experiments were carried out at different maturity stages such as 30, 50, and 70 days (after sowing). The results demonstrated that the root length, proline, glycine betaine, amino acid and superoxide dismutase, catalase and peroxidase activities were boosted in all treatments as compared with control. As the proso millet matured, the length of shoots and the amount of chlorophyll pigment in the leaves reduced in all treatments as compared to control. Induced reduction of shoot growth, chlorophyll estimation and increases of root growth, osmolyte accumulations, antioxidant enzymes, were found to be drought-tolerant adaptative mechanisms in this study.