RESUMEN
Lodging restricts growth, development, and yield formation in maize (Zea mays L.). Shorter internode length is beneficial for lodging tolerance. However, although brassinosteroids (BRs) and jasmonic acid (JA) are known to antagonistically regulate internode growth, the underlying molecular mechanism is still unclear. In this study, application of the JA mimic coronatine (COR) inhibited basal internode elongation at the jointing stage and repressed expression of the cell wall-related gene XYLOGLUCAN ENDOTRANSGLUCOSYLASE/HYDROLASE 1 (ZmXTH1), whose overexpression in maize plants promoted internode elongation. We demonstrated that the basic helix-loop-helix (bHLH) transcription factor ZmbHLH154 directly binds to the ZmXTH1 promoter and induces its expression, whereas the bHLH transcription factor ILI1 BINDING BHLH 1 (ZmIBH1) inhibits this transcriptional activation by forming a heterodimer with ZmbHLH154. Overexpressing ZmbHLH154 led to longer internodes, whereas zmbhlh154 mutants had shorter internodes than the wild type. The core JA-dependent transcription factors ZmMYC2-4 and ZmMYC2-6 interacted with BRASSINAZOLE RESISTANT 1 (ZmBZR1), a key factor in BR signaling, and these interactions eliminated the inhibitory effect of ZmBZR1 on its downstream gene ZmIBH1. Collectively, these results reveal a signaling module in which JA regulates a bHLH network by attenuating BR signaling to inhibit ZmXTH1 expression, thereby regulating cell elongation in maize.
Asunto(s)
Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico , Brasinoesteroides , Ciclopentanos , Regulación de la Expresión Génica de las Plantas , Oxilipinas , Proteínas de Plantas , Transducción de Señal , Zea mays , Brasinoesteroides/metabolismo , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/metabolismo , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética , Oxilipinas/metabolismo , Oxilipinas/farmacología , Ciclopentanos/metabolismo , Ciclopentanos/farmacología , Zea mays/genética , Zea mays/metabolismo , Zea mays/efectos de los fármacos , Zea mays/crecimiento & desarrollo , Transducción de Señal/efectos de los fármacos , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Indenos/farmacología , Plantas Modificadas Genéticamente , Regiones Promotoras Genéticas/genética , Reguladores del Crecimiento de las Plantas/metabolismo , Reguladores del Crecimiento de las Plantas/farmacología , AminoácidosRESUMEN
Maize is a valuable raw material for feed and food production. Healthy seed germination is important for improving the yield and quality of maize. Seed aging occurs relatively fast in crops and it is a process that delays germination as well as reduces its rate and even causes total loss of seed viability. However, the physiological and transcriptional mechanisms that regulate maize seeds, especially aging seed germination remain unclear. Coronatine (COR) which is a phytotoxin produced by Pseudomonas syringae and a new type of plant growth regulator can effectively regulate plant growth and development, and regulate seed germination. In this study, the physiological and transcriptomic mechanisms of COR-induced maize seed germination under different aging degrees were analyzed. The results showed that 0.001-0.01 µmol/L COR could promote the germination of aging maize seed and the growth of primary roots and shoots. COR treatment increased the content of gibberellins (GA3) and decreased the content of abscisic acid (ABA) in B73 seeds before germination. The result of RNA-seq analysis showed 497 differentially expressed genes in COR treatment compared with the control. Three genes associated with GA biosynthesis (ZmCPPS2, ZmD3, and ZmGA2ox2), and two genes associated with GA signaling transduction (ZmGID1 and ZmBHLH158) were up-regulated. Three genes negatively regulating GA signaling transduction (ZmGRAS48, ZmGRAS54, and Zm00001d033369) and two genes involved in ABA biosynthesis (ZmVP14 and ZmPCO14472) were down-regulated. The physiological test results also showed that the effects of GA and ABA on seed germination were similar to those of high and low-concentration COR, respectively, which indicated that the effect of COR on seed germination may be carried out through GA and ABA pathways. In addition, GO and KEGG analysis suggested that COR is also highly involved in antioxidant enzyme systems and secondary metabolite synthesis to regulate maize seed germination processes. These findings provide a valuable reference for further research on the mechanisms of maize seed germination.
Asunto(s)
Ácido Abscísico , Regulación de la Expresión Génica de las Plantas , Germinación , Giberelinas , Reguladores del Crecimiento de las Plantas , Semillas , Zea mays , Germinación/genética , Germinación/efectos de los fármacos , Zea mays/genética , Zea mays/crecimiento & desarrollo , Zea mays/fisiología , Semillas/genética , Semillas/crecimiento & desarrollo , Ácido Abscísico/metabolismo , Giberelinas/metabolismo , Reguladores del Crecimiento de las Plantas/metabolismo , Aminoácidos/metabolismo , Indenos/farmacología , Transcriptoma , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Perfilación de la Expresión Génica , Transducción de SeñalRESUMEN
High-affinity K+ (HAK) transporters play essential roles in facilitating root K+ uptake in higher plants. Our previous studies revealed that GhHAK5a, a member of the HAK family, is crucial for K+ uptake in upland cotton. Nevertheless, the precise regulatory mechanism governing the expression of GhHAK5a remains unclear. The yeast one-hybrid screening was performed to identify the transcription factors responsible for regulating GhHAK5a, and ethylene response factor 9 (GhERF9) was identified as a potential candidate. Subsequent dual-luciferase and electrophoretic mobility shift assays confirmed that GhERF9 binds directly to the GhHAK5a promoter, thereby activating its expression. Silencing of GhERF9 decreased the expression of GhHAK5a and exacerbated K+ deficiency symptoms in leaves, also decreased K+ uptake rate and K+ content in roots. Additionally, it was observed that the application of ethephon (an ethylene-releasing reagent) resulted in a significant upregulation of GhERF9 and GhHAK5a, accompanied by an increased rate of K+ uptake. Expectedly, GhEIN3b and GhEIL3c, the two key components involved in ethylene signaling, bind directly to the GhERF9 promoter. These findings provide valuable insights into the molecular mechanisms underlying the expression of GhHAK5a and ethylene-mediated K+ uptake and suggest a potential strategy to genetically enhance cotton K+ uptake by exploiting the EIN3/EILs-ERF9-HAK5 module.
Asunto(s)
Gossypium , Proteínas de Unión al ADN/metabolismo , Etilenos/metabolismo , Regulación de la Expresión Génica de las Plantas , Gossypium/genética , Gossypium/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismoRESUMEN
Plants can contain biosynthetic gene clusters (BGCs) that nominally resemble those found in microbes. However, while horizontal gene transmission is often observed in microbes, plants are limited to vertical gene transmission, implying that their BGCs may exhibit distinct inheritance patterns. Rice (Oryza sativa) contains two unlinked BGCs involved in diterpenoid phytoalexin metabolism, with one clearly required for momilactone biosynthesis, while the other is associated with production of phytocassanes. Here, in the process of elucidating momilactone biosynthesis, genetic evidence was found demonstrating a role for a cytochrome P450 (CYP) from the other "phytocassane" BGC. This CYP76M8 acts after the CYP99A2/3 from the "momilactone" BGC, producing a hemiacetal intermediate that is oxidized to the eponymous lactone by a short-chain alcohol dehydrogenase also from this BGC. Thus, the "momilactone" BGC is not only incomplete, but also fractured by the need for CYP76M8 to act in between steps catalyzed by enzymes from this BGC. Moreover, as supported by similar activity observed with orthologs from the momilactone-producing wild-rice species Oryza punctata, the presence of CYP76M8 in the other "phytocassane" BGC indicates interdependent evolution of these two BGCs, highlighting the distinct nature of BGC assembly in plants.
Asunto(s)
Evolución Biológica , Vías Biosintéticas/genética , Diterpenos/metabolismo , Familia de Multigenes , Oryza/genética , Diterpenos/química , Regulación de la Expresión Génica de las Plantas , Oxidación-Reducción , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismoRESUMEN
Bacterial diseases are one of the most common issues that result in crop loss worldwide, and the increasing usage of chemical pesticides has caused the occurrence of resistance in pathogenic bacteria and environmental pollution problems. Nanomaterial mediated gene silencing is starting to display powerful efficiency and environmental friendliness for improving plant disease resistance. However, the internalization of nanomaterials and the physiological mechanisms behind nano-improved plant disease resistance are still rarely understood. We engineered the polyethyleneimine (PEI) functionalized gold nanoparticles (PEI-AuNPs) with fluorescent properties and ROS scavenging activity to act as siRNA delivery platforms. Besides the loading, protection, and delivery of nucleic acid molecules in plant mature leaf cells by PEI-AuNPs, its fluorescent property further enables the traceability of the distribution of the loaded nucleic acid molecules in cells. Additionally, the PEI-AuNPs-based RNAi delivery system successfully mediated the silencing of defense-regulated gene AtWRKY1. Compared to control plants, the silenced plants performed better resistance to Pseudomonas syringae, showing a reduced bacterial number, decreased ROS content, increased antioxidant enzyme activities, and improved chlorophyll fluorescence performance. Our results showed the advantages of AuNP-based RNAi technology in improving plant disease resistance, as well as the potential of plant nanobiotechnology to protect agricultural production.
Asunto(s)
Resistencia a la Enfermedad , Oro , Nanopartículas del Metal , Enfermedades de las Plantas , Pseudomonas syringae , ARN Interferente Pequeño , Especies Reactivas de Oxígeno , Oro/química , Nanopartículas del Metal/química , Especies Reactivas de Oxígeno/metabolismo , Enfermedades de las Plantas/microbiología , Polietileneimina/química , Silenciador del Gen , Arabidopsis/genéticaRESUMEN
Plant growth exhibits rhythmic characteristics, and gibberellins (GAs) are involved in regulating cell growth, but it is still unclear how GAs crosstalk with circadian rhythm to regulate cell elongation. The study analyzed growth characteristics of wild-type (WT), zmga3ox and zmga3ox with GA3 seedlings. We integrated metabolomes and transcriptomes to study the interaction between GAs and circadian rhythm in mediating leaf elongation. The rates of leaf growth were higher in WT than zmga3ox, and zmga3ox cell length was shorter when proliferated in darkness than light, and GA3 restored zmga3ox leaf growth. The differentially expressed genes (DEGs) between WT and zmga3ox were mainly enriched in hormone signaling and cell wall synthesis, while DEGs in zmga3ox were restored to WT by GA3. Moreover, the number of circadian DEGs that reached the peak expression in darkness was more than light, and the upregulated circadian DEGs were mainly enriched in cell wall synthesis. The differentially accumulated metabolites (DAMs) were mainly attributed to flavonoids and phenolic acid. Twenty-two DAMs showed rhythmic accumulation, especially enriched in lignin synthesis. The circadian DEGs ZmMYBr41/87 and ZmHB34/70 were identified as regulators of ZmHCT8 and ZmBM1, which were enzymes in lignin synthesis. Furthermore, GAs regulated ZmMYBr41/87 and ZmHB34/70 to modulate lignin biosynthesis for mediating leaf rhythmic growth.
Asunto(s)
Giberelinas , Zea mays , Giberelinas/metabolismo , Zea mays/genética , Lignina/metabolismo , Perfilación de la Expresión Génica , Transcriptoma , Hojas de la Planta/metabolismo , Ritmo Circadiano , Regulación de la Expresión Génica de las PlantasRESUMEN
BACKGROUND: Auxin plays a crucial role in nitrate (NO3-)-mediated root architecture, and it is still unclear that if NO3- supply modulates auxin reallocation for regulating root formation in maize (Zea mays L.). This study was conducted to investigate the role of auxin efflux carrier ZmPIN1a in the root formation in response to NO3- supply. RESULTS: Low NO3- (LN) promoted primary root (PR) elongation, while repressed the development of lateral root primordia (LRP) and total root length. LN modulated auxin levels and polar transport and regulated the expression of auxin-responsive and -signaling genes in roots. Moreover, LN up-regulated the expression level of ZmPIN1a, and overexpression of ZmPIN1a enhanced IAA efflux and accumulation in PR tip, while repressed IAA accumulation in LRP initiation zone, which consequently induced LN-mediated PR elongation and LR inhibition. The inhibition rate of PR length, LRP density and number of ZmPIN1a-OE plants was higher than that of wild-type plants after auxin transport inhibitor NPA treatment under NN and LN conditions, and the degree of inhibition of root growth in ZmPIN1a-OE plants was more obvious under LN condition. CONCLUSION: These findings suggest that ZmPIN1a was involved in modulating auxin levels and transport to alter NO3--mediated root formation in maize.
Asunto(s)
Ácidos Indolacéticos , Nitratos , Ácidos Indolacéticos/metabolismo , Nitratos/metabolismo , Raíces de Plantas/metabolismo , Regulación de la Expresión Génica de las Plantas , Transporte Biológico/genética , Zea mays/metabolismoRESUMEN
The lengths of the basal internodes is an important factor for lodging resistance of maize (Zea mays). In this study, foliar application of coronatine (COR) to 10 cultivars at the V8 growth stage had different suppression effects on the length of the eighth internode, with three being categorized as strong-inhibition cultivars (SC), five as moderate (MC), and two as weak (WC). RNA-sequencing of the eighth internode of the cultivars revealed a total of 7895 internode elongation-regulating genes, including 777 transcription factors (TFs). Genes related to the hormones cytokinin, gibberellin, auxin, and ethylene in the SC group were significantly down-regulated compared to WC, and more cell-cycle regulatory factors and cell wall-related genes showed significant changes, which severely inhibited internode elongation. In addition, we used EMSAs to explore the direct regulatory relationship between two important TFs, ZmABI7 and ZmMYB117, which regulate the cell cycle and cell wall modification by directly binding to the promoters of their target genes ZmCYC1, ZmCYC3, ZmCYC7, and ZmCPP1. The transcriptome reported in this study will provide a useful resource for studying maize internode development, with potential use for targeted genetic control of internode length to improve the lodging resistance of maize.
Asunto(s)
Ácidos Indolacéticos , Zea mays , Zea mays/metabolismo , Ácidos Indolacéticos/metabolismo , Giberelinas/metabolismo , Transcriptoma , Análisis de Secuencia de ARN , Regulación de la Expresión Génica de las PlantasRESUMEN
Rare-earth (RE)-based honeycomb-lattice materials with strong spin-orbit coupled Jeff = 1/2 moments have attracted great interest as a platform to realize the Kitaev quantum spin liquid (QSL) state. Herein, we report the discovery of a family of RE-based honeycomb-lattice magnets Ba9RE2(SiO4)6 (RE = Ho-Yb), which crystallize into the rhombohedral structure with the space group R3Ì . In these serial compounds, magnetic RE3+ ions are arranged on a perfect honeycomb lattice within the ab-plane and stacked in the "ABCABC"-type fashion along the c-axis. All synthesized Ba9RE2(SiO4)6 (RE = Ho-Yb) polycrystals exhibit the dominant antiferromagnetic interaction and absence of magnetic order down to 2 K. In combination with the magnetization and electron spin resonance results, magnetic behaviors are discussed for the compounds with different RE ions. Moreover, the as-grown Ba9Yb2(SiO4)6 single crystals show large magnetic frustration with frustration index f = θCW/TN > 8 and no long-range magnetic ordering down to 0.15 K, being a possible QSL candidate material. These series of compounds are attractive for exploring the exotic magnetic phases of Kitaev materials with 4f electrons.
RESUMEN
Excessive nitrogen (N) fertilization in agroecological systems increases nitrous oxide (N2O) emissions. 3,4-dimethylpyrazole phosphate (DMPP) is used to mitigate N2O losses. The influence of DMPP efficiency on N2O mitigation was clearly affected by spatiotemporal heterogeneity. Using field and incubation experiments combined with metagenomic sequencing, we aimed to investigate DMPP efficiency and the underlying microbial mechanisms in dark-brown (Siping, SP), fluvo-aquic (Cangzhou, CZ; Xinxiang, XX), and red soil (Wenzhou, WZ) from diverse climatic zones. In the field experiments, the DMPP efficiency in N2O mitigation ranged from 51.6% to 89.9%, in the order of XX, CZ, SP, and WZ. The DMPP efficiency in the incubation experiments ranged from 58.3% to 93.9%, and the order of efficiency from the highest to lowest was the same as that of the field experiments. Soil organic matter, total N, pH, texture, and taxonomic and functional α-diversity were important soil environment and microbial factors for DMPP efficiency. DMPP significantly enriched ammonia-oxidizing archaea (AOA) and nitrite-oxidizing bacteria (NOB), which promoted N-cycling with low N2O emissions. Random forest (RF) and regression analyses found that an AOA (Nitrosocosmicus) and NOB (Nitrospina) demonstrated important and positive correlation with DMPP efficiency. Moreover, genes associated with carbohydrate metabolism were important for DMPP efficiency and could influenced N-cycling and DMPP metabolism. The similar DMPP efficiency indicated that the variation in DMPP efficiency was significantly due to soil physicochemical and microbial variations. In conclusion, filling the knowledge gap regarding the response of DMPP efficiency to abiotic and biotic factors could be beneficial in DMPP applications, and in adapting more efficient strategies to improve DMPP efficiency and mitigate N2O emissions in multiple regions.
Asunto(s)
Óxido Nitroso , Fosfatos , Fosfatos/análisis , Yoduro de Dimetilfenilpiperazina/metabolismo , Bacterias/genética , Bacterias/metabolismo , Suelo , China , Amoníaco , Nitritos/análisis , Nitritos/metabolismo , Microbiología del Suelo , Fertilizantes/análisisRESUMEN
Thidiazuron (TDZ) is a widely used chemical defoliant in cotton and can stimulate the production of ethylene in leaves, which is believed to be the key factor in inducing leaf abscission. Ethephon (Eth) can also stimulate ethylene production in leaves, but it is less effective in promoting leaf shedding. In this study, the enzyme-linked immunosorbent assays (ELISA) and RNA-seq were used to determine specific changes at hormonal levels as well as transcriptomic mechanisms induced by TDZ compared with Eth. The TDZ significantly reduced the levels of auxin and cytokinin in cotton leaves, but no considerable changes were observed for Eth. In addition, TDZ specifically increased the levels of brassinosteroids and jasmonic acid in the leaves. A total of 13 764 differentially expressed genes that specifically responded to TDZ were identified by RNA-seq. The analysis of KEGG functional categories suggested that the synthesis, metabolism, and signal transduction of auxin, cytokinin, and brassinosteroid were all involved in the TDZ-induced abscission of cotton leaves. Eight auxin transport genes (GhPIN1-c_D, GhPIN3_D, GhPIN8_A, GhABCB19-b_A, GhABCB19-b_D, GhABCB2-b_D, GhLAX6_A, and GhLAX7_D) specifically responded to TDZ. The pro35S::GhPIN3a::YFP transgenic plants showed lower defoliation than the wild type treated with TDZ, and YFP fluorescence in leaves was almost extinguished after treatment with TDZ rather than Eth. This provides direct evidence that GhPIN3a is involved in the leaf abscission induced by TDZ. We found that 959 transcription factors (TFs) specifically responded to TDZ, and a co-expression network analysis (WGCNA) showed five hub TFs (GhNAC72, GhWRKY51, GhWRKY70, GhWRKY50, and GhHSF24) during chemical defoliation with TDZ. Our work sheds light on the molecular basis of TDZ-induced leaf abscission in cotton.
Asunto(s)
Etilenos , Transcriptoma , Etilenos/metabolismo , Citocininas/metabolismo , Ácidos Indolacéticos/farmacología , Ácidos Indolacéticos/metabolismoRESUMEN
Straw retention (SR) and organic fertilizer (OF) application contribute to improve soil quality, but it is unclear how the soil microbial assemblage under organic amendments mediate soil biochemical metabolism pathways to perform it. This study collected soil samples from wheat field under different application of fertilizer (chemical fertilizer, as control; SR, and OF) in North China Plain, and systematically investigated the interlinkages among microbe assemblages, metabolites, and physicochemical properties. Results showed that the soil organic carbon (SOC) and permanganate oxidizable organic carbon (LOC) in soil samples followed the trend as OF > SR > control, and the activity of C-acquiring enzymes presented significantly positive correlation with SOC and LOC. In organic amendments, bacteria and fungi community were respectively dominated by deterministic and stochastic processes, while OF exerted more selective pressure on soil microbe. Compared with SR, OF had greater potential to boost the microbial community robustness through increasing the natural connectivity and stimulating fungal taxa activities in inter-kingdom microbial networks. Altogether 67 soil metabolites were significantly affected by organic amendments, most of them belonged to benzenoids (Ben), lipids and lipid-like molecules (LL), and organic acids and derivatives (OA). These metabolites were mainly derived from lipid and amino acid metabolism pathways. A list of keystone genera such as stachybotrys and phytohabitans were identified as important to soil metabolites, SOC, and C-acquiring enzyme activity. Structural equation modeling showed that soil quality properties were closely associated with LL, OA, and PP drove by microbial community assembly and keystone genera. Overall, these findings suggested that straw and organic fertilizer might drive keystone genera dominated by determinism to mediate soil lipid and amino acid metabolism for improving soil quality, which provided new insights into understanding the microbial-mediated biological process in amending soil quality.
Asunto(s)
Microbiota , Suelo , Suelo/química , Carbono/química , Agricultura/métodos , Triticum/metabolismo , Zea mays/metabolismo , Fertilizantes/análisis , Microbiología del Suelo , Aminoácidos/metabolismo , LípidosRESUMEN
Water uptake is crucial for crop growth and development and drought stress tolerance. The water channel aquaporins (AQP) play important roles in plant water uptake. Here, we discovered that a jasmonic acid analog, coronatine (COR), enhanced maize (Zea mays) root water uptake capacity under artificial water deficiency conditions. COR treatment induced the expression of the AQP gene Plasma membrane intrinsic protein 2;5 (ZmPIP2;5). In vivo and in vitro experiments indicated that COR also directly acts on ZmPIP2;5 to improve water uptake in maize and Xenopus oocytes. The leaf water potential and hydraulic conductivity of roots growing under hyperosmotic conditions were higher in ZmPIP2;5-overexpression lines and lower in the zmpip2;5 knockout mutant, compared to wild-type plants. Based on a comparison between ZmPIP2;5 and other PIP2s, we predicted that COR may bind to the functional site in loop E of ZmPIP2;5. We confirmed this prediction by surface plasmon resonance technology and a microscale thermophoresis assay, and showed that deleting the binding motif greatly reduced COR binding. We identified the N241 residue as the COR-specific binding site, which may activate the channel of the AQP tetramer and increase water transport activity, which may facilitate water uptake under hyperosmotic stress.
Asunto(s)
Acuaporinas , Zea mays , Zea mays/genética , Agua/metabolismo , Membrana Celular/metabolismo , Acuaporinas/química , Acuaporinas/genética , Acuaporinas/metabolismo , Proteínas de la Membrana/metabolismo , Raíces de Plantas/metabolismo , Proteínas de Plantas/metabolismo , Regulación de la Expresión Génica de las PlantasRESUMEN
BACKGROUND: Low grain water content (GWC) at harvest of maize (Zea mays L.) is essential for mechanical harvesting, transportation and storage. Grain drying rate (GDR) is a key determinant of GWC. Many quantitative trait locus (QTLs) related to GDR and GWC have been reported, however, the confidence interval (CI) of these QTLs are too large and few QTLs has been fine-mapped or even been cloned. Meta-QTL (MQTL) analysis is an effective method to integrate QTLs information in independent populations, which helps to understand the genetic structure of quantitative traits. RESULTS: In this study, MQTL analysis was performed using 282 QTLs from 25 experiments related GDR and GWC. Totally, 11 and 34 MQTLs were found to be associated with GDR and GWC, respectively. The average CI of GDR and GWC MQTLs was 24.44 and 22.13 cM which reduced the 57 and 65% compared to the average QTL interval for initial GDR and GWC QTL, respectively. Finally, 1494 and 5011 candidate genes related to GDR and GWC were identified in MQTL intervals, respectively. Among these genes, there are 48 genes related to hormone metabolism. CONCLUSIONS: Our studies combined traditional QTL analyses, genome-wide association study and RNA-seq to analysis major locus for regulating GWC in maize.
Asunto(s)
Sitios de Carácter Cuantitativo , Zea mays , Mapeo Cromosómico/métodos , Deshidratación/genética , Grano Comestible/metabolismo , Estudio de Asociación del Genoma Completo , Hormonas/análisis , Hormonas/metabolismo , Fenotipo , Sitios de Carácter Cuantitativo/genética , Agua/metabolismo , Zea mays/genética , Zea mays/metabolismoRESUMEN
Rice (Oryza sativa) is a staple food crop and serves as a model cereal plant. It contains two biosynthetic gene clusters (BGCs) for the production of labdane-related diterpenoids (LRDs), which serve important roles in combating biotic and abiotic stress. While plant BGCs have been subject to genetic analyses, these analyses have been largely confined to the investigation of single genes. CRISPR/Cas9-mediated genome editing was used to precisely remove each of these BGCs, as well as simultaneously knock out both BGCs. Deletion of the BGC from chromosome 2 (c2BGC), which is associated with phytocassane biosynthesis, but not that from chromosome 4 (c4BGC), which is associated with momilactone biosynthesis, led to a lesion mimic phenotype. This phenotype is dependent on two closely related genes encoding cytochrome P450 (CYP) mono-oxygenases, CYP76M7 and CYP76M8, from the c2BGC. However, rather than being redundant, CYP76M7 has been associated with the production of phytocassanes, whereas CYP76M8 is associated with momilactone biosynthesis. Intriguingly, the lesion mimic phenotype is not present in a line with both BGCs deleted. These results reveal directional cross-cluster phytotoxicity, presumably arising from the accumulation of LRD intermediates dependent on the c4BGC in the absence of CYP76M7 and CYP76M8, further highlighting their interdependent evolution and the selective pressures driving BGC assembly.
Asunto(s)
Diterpenos , Oryza , Sistema Enzimático del Citocromo P-450/genética , Grano Comestible/genética , Familia de Multigenes , Oryza/genéticaRESUMEN
APETALA2/ETHYLENE RESPONSIVE FACTOR (AP2/ERF) family transcription factors have well-documented functions in stress responses, but their roles in brassinosteroid (BR)-regulated growth and stress responses have not been established. Here, we show that the Arabidopsis (Arabidopsis thaliana) stress-inducible AP2/ERF transcription factor TINY inhibits BR-regulated growth while promoting drought responses. TINY-overexpressing plants have stunted growth, increased sensitivity to BR biosynthesis inhibitors, and compromised BR-responsive gene expression. By contrast, tiny tiny2 tiny3 triple mutants have increased BR-regulated growth and BR-responsive gene expression. TINY positively regulates drought responses by activating drought-responsive genes and promoting abscisic acid-mediated stomatal closure. Global gene expression studies revealed that TINY and BRs have opposite effects on plant growth and stress response genes. TINY interacts with and antagonizes BRASSINOSTERIOID INSENSITIVE1-ETHYL METHANESULFONATE SUPRESSOR1 (BES1) in the regulation of these genes. Glycogen synthase kinase 3-like protein kinase BR-INSENSITIVE2 (BIN2), a negative regulator in the BR pathway, phosphorylates and stabilizes TINY, providing a mechanism for BR-mediated downregulation of TINY to prevent activation of stress responses under optimal growth conditions. Taken together, our results demonstrate that BR signaling negatively regulates TINY through BIN2 phosphorylation and TINY positively regulates drought responses, as well as inhibiting BR-mediated growth through TINY-BES1 antagonistic interactions. Our results thus provide insight into the coordination of BR-regulated growth and drought responses.
Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Arabidopsis/fisiología , Proteínas de Homeodominio/metabolismo , Plantas Modificadas Genéticamente/metabolismo , Plantas Modificadas Genéticamente/fisiología , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Sequías , Regulación de la Expresión Génica de las Plantas/genética , Regulación de la Expresión Génica de las Plantas/fisiología , Proteínas de Homeodominio/genética , Plantas Modificadas Genéticamente/genética , Proteínas Quinasas/genética , Proteínas Quinasas/metabolismo , Transducción de Señal/genética , Transducción de Señal/fisiologíaRESUMEN
BACKGROUND: MicroRNA (miRNA) plays vital roles in the regulation of both plant architecture and stress resistance through cleavage or translation inhibition of the target messenger RNAs (mRNAs). However, miRNA-induced gene silencing remains a major challenge in vivo due to the low delivery efficiency and instability of miRNA, thus an efficient and simple method is urgently needed for miRNA transformation. Previous researches have constructed a star polycation (SPc)-mediated transdermal double-stranded RNA (dsRNA) delivery system, achieving efficient dsRNA delivery and gene silencing in insect pests. RESULTS: Here, we tested SPc-based platform for direct delivery of double-stranded precursor miRNA (ds-MIRNA) into protoplasts and plants. The results showed that SPc could assemble with ds-MIRNA through electrostatic interaction to form nano-sized ds-MIRNA/SPc complex. The complex could penetrate the root cortex and be systematically transported through the vascular tissue in seedlings of Arabidopsis and maize. Meanwhile, the complex could up-regulate the expression of endocytosis-related genes in both protoplasts and plants to promote the cellular uptake. Furthermore, the SPc-delivered ds-MIRNA could efficiently increase mature miRNA amount to suppress the target gene expression, and the similar phenotypes of Arabidopsis and maize were observed compared to the transgenic plants overexpressing miRNA. CONCLUSION: To our knowledge, we report the first construction and application of star polycation nanocarrier-based platform for miRNA delivery in plants, which explores a new enable approach of plant biotechnology with efficient transformation for agricultural application.
Asunto(s)
Arabidopsis , MicroARNs , Arabidopsis/genética , Regulación de la Expresión Génica de las Plantas , Silenciador del Gen , MicroARNs/genética , MicroARNs/metabolismo , Polielectrolitos , Zea mays/genética , Zea mays/metabolismoRESUMEN
Thidiazuron (TDZ) is widely used as a defoliant to induce leaf abscission in cotton. However, the underlying molecular mechanism is still unclear. In this study, RNA-seq and enzyme-linked immunosorbent assays (ELISA) were performed to reveal the dynamic transcriptome profiling and the change of endogenous phytohormones upon TDZ treatment in leaf, petiole, and abscission zone (AZ). We found that TDZ induced the gene expression of ethylene biosynthesis and signal, and promoted ethylene accumulation earlier in leaf than that in AZ. While TDZ down-regulated indole-3-acetic acid (IAA) biosynthesis genes mainly in leaf and IAA signal and transport genes. Furthermore, the IAA content reduced more sharply in the leaf than that in AZ to change the auxin gradient for abscission. TDZ suppressed CTK biosynthesis genes and induced CTK metabolic genes to reduce the IPA accumulation for the reduction of ethylene sensitivity. Furthermore, TDZ regulated the gene expression of abscisic acid (ABA) biosynthesis and signal and induced ABA accumulation between 12-48 h, which could up-regulate ABA response factor genes and inhibit IAA transporter genes. Our data suggest that TDZ orchestrates metabolism and signal of ethylene, auxin, and cytokinin, and also the transport of auxin in leaf, petiole, and AZ, to control leaf abscission.
Asunto(s)
Citocininas , Regulación de la Expresión Génica de las Plantas , Etilenos , Ácidos Indolacéticos/metabolismo , Compuestos de Fenilurea , Hojas de la Planta/metabolismo , TiadiazolesRESUMEN
BACKGROUND: Lodging is one of the important factors causing maize yield. Plant height is an important factor in determining plant architecture in maize (Zea mays L.), which is closely related to lodging resistance under high planting density. Coronatine (COR), which is a phytotoxin and produced by the pathogen Pseudomonas syringae, is a functional and structural analogue of jasmonic acid (JA). RESULTS: In this study, we found COR, as a new plant growth regulator, could effectively reduce plant height and ear height of both hybrids (ZD958 and XY335) and inbred (B73) maize by inhibiting internode growth during elongation, thus improve maize lodging resistance. To study gene expression changes in internode after COR treatment, we collected spatio-temporal transcriptome of inbred B73 internode under normal condition and COR treatment, including the three different regions of internode (fixed, meristem and elongation regions) at three different developmental stages. The gene expression levels of the three regions at normal condition were described and then compared with that upon COR treatment. In total, 8605 COR-responsive genes (COR-RGs) were found, consist of 802 genes specifically expressed in internode. For these COR-RGs, 614, 870, 2123 of which showed expression changes in only fixed, meristem and elongation region, respectively. Both the number and function were significantly changed for COR-RGs identified in different regions, indicating genes with different functions were regulated at the three regions. Besides, we found more than 80% genes of gibberellin and jasmonic acid were changed under COR treatment. CONCLUSIONS: These data provide a gene expression profiling in different regions of internode development and molecular mechanism of COR affecting internode elongation. A putative schematic of the internode response to COR treatment is proposed which shows the basic process of COR affecting internode elongation. This research provides a useful resource for studying maize internode development and improves our understanding of the COR regulation mechanism based on plant height.
Asunto(s)
Aminoácidos/farmacología , Giberelinas/farmacología , Indenos/farmacología , Reguladores del Crecimiento de las Plantas/farmacología , Pseudomonas syringae/química , Transcriptoma , Zea mays/genética , Ciclopentanos/farmacología , Perfilación de la Expresión Génica , Regulación del Desarrollo de la Expresión Génica , Regulación de la Expresión Génica de las Plantas , Oxilipinas/farmacología , Tallos de la Planta/efectos de los fármacos , Tallos de la Planta/genética , Tallos de la Planta/crecimiento & desarrollo , Zea mays/efectos de los fármacos , Zea mays/crecimiento & desarrolloRESUMEN
Rice (Oryza sativa) is the staple food for over half the world's population. Drought stress imposes major constraints on rice yields. Intriguingly, labdane-related diterpenoid (LRD) phytoalexins in maize (Zea mays) affect drought tolerance, as indicated by the increased susceptibility of an insertion mutant of the class II diterpene cyclase ZmCPS2/An2 that initiates such biosynthesis. Rice also produces LRD phytoalexins, utilizing OsCPS2 and OsCPS4 to initiate a complex metabolic network. For genetic studies of rice LRD biosynthesis the fast-growing Kitaake cultivar was selected for targeted mutagenesis via CRISPR/Cas9, with an initial focus on OsCPS2 and OsCPS4. The resulting cps2 and cps4 knockout lines were further crossed to create a cps2x4 double mutant. Both CPSs also were overexpressed. Strikingly, all of the cv Kitaake cps mutants exhibit significantly increased susceptibility to drought, which was associated with reduced stomatal closure that was evident even under well-watered conditions. However, CPS overexpression did not increase drought resistance, and cps mutants in other cultivars did not alter susceptibility to drought, although these also exhibited lesser effects on LRD production. The results suggest that LRDs may act as a regulatory switch that triggers stomatal closure in rice, which might reflect the role of these openings in microbial entry.