RESUMEN
The plant root absorbs water and nutrients, anchors the plant in the soil, and promotes plant development. Root is developed from root apical meristem (RAM), which is formed during embryo stage and is maintained by dividing stem cells. Plant hormones have a predominant role in RAM maintenance. This review evaluates the functional crosstalk among three major hormones (auxin, cytokinin, and brassinolide) in RAM development in Arabidopsis, integrating a variety of experimental data into a regulatory network and revealing multiple layers of complexity in the crosstalk among these three hormones. We also discuss possible directions for future research on the roles of hormones in regulating RAM development and maintenance.
Asunto(s)
Arabidopsis , Reguladores del Crecimiento de las Plantas , Raíces de Plantas , Reguladores del Crecimiento de las Plantas/metabolismo , Raíces de Plantas/metabolismo , Raíces de Plantas/crecimiento & desarrollo , Arabidopsis/metabolismo , Arabidopsis/crecimiento & desarrollo , Meristema/metabolismo , Meristema/crecimiento & desarrollo , Citocininas/metabolismo , Ácidos Indolacéticos/metabolismo , Regulación de la Expresión Génica de las Plantas , Brasinoesteroides/metabolismoRESUMEN
Blossom end enlargement (BEE) is a postharvest deformation that may be related to the influx of photosynthetic assimilates before harvest. To elucidate the mechanism by which BEE occurs, expression marker genes that indicate the physiological condition of BEE-symptomatic fruit are necessary. First, we discovered that preharvest treatment with a synthetic cytokinin, N-(2-Chloro-4-pyridyl)-N'-phenylurea (CPPU), promoted fruit growth and suppressed BEE occurrence. This suggests that excessive assimilate influx is not a main cause of BEE occurrence. Subsequently, the expression levels of seven sugar-starvation marker genes, CsSEF1, AS, CsFDI1, CsPID, CsFUL1, CsETR1, and CsERF1B, were compared among symptomatic and asymptomatic fruits, combined with and without CPPU treatment. Only CsSEF1 showed a higher expression level in asymptomatic fruits than in symptomatic fruits, regardless of CPPU treatment. This was then tested using fruits stored via the modified-atmosphere packaging technique, which resulted in a lower occurrence of BEE, and the asymptomatic fruits showed a higher CsSEF1 expression level than symptomatic fruits, regardless of the packaging method. CsSEF1 codes a CCCH-type zinc finger protein, and an increase in the expression of CsSEF1 was correlated with a decrease in the fruit respiration rate. Thus, CsSEF1 may be usable as a BEE expression marker gene.
Asunto(s)
Cucumis sativus , Frutas , Regulación de la Expresión Génica de las Plantas , Proteínas de Plantas , Frutas/genética , Frutas/metabolismo , Cucumis sativus/genética , Cucumis sativus/crecimiento & desarrollo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Citocininas/metabolismoRESUMEN
Pathogenesis-related protein 1 (PR-1) is an antimicrobial protein involved in systemic acquired resistance (SAR) in plants, but its regulatory role and interactions with other pathways remain unclear. In this study, we functionally characterize WsPR-1 gene of Withania somnifera in Nicotiana tabacum to elucidate its role in plant defense, growth, and development. Interestingly, transgenic tobacco plants with increased levels of cytokinin (CK) and decreased gibberellins (GAs) exhibited stunted shoot growth, an underdeveloped root system, modified leaf morphology, reduced seed pod production, and delayed leaf senescence. Transcriptional analysis revealed that WsPR-1 overexpression downregulated the GA 20-oxidase (GA20ox) gene involved in GA biosynthesis while upregulating GA 2-oxidase (GA2ox), a GA catabolic enzyme. Moreover, transcript levels of FRUITFULL (FUL) and LEAFY (NFL2) flowering genes exhibited a decrease in WsPR-1 plants, which could explain the delayed flowering and reduced seed pod development in transgenic plants. Confocal microscopy confirmed increased lignin deposition in stem cross-sections of WsPR-1 transgenic plants, supported by gene expression analysis and lignin content quantification. Additionally, our findings also suggest the involvement of Knotted1-like homeobox (KNOX) gene in enhancing cytokinin levels. This study highlights PR-1's regulatory role in plant growth and development, with potential to boost crop yields and enhance resilience.
Asunto(s)
Citocininas , Regulación de la Expresión Génica de las Plantas , Giberelinas , Proteínas de Plantas , Plantas Modificadas Genéticamente , Transducción de Señal , Citocininas/metabolismo , Giberelinas/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Nicotiana/genética , Nicotiana/metabolismo , Hojas de la Planta/metabolismo , Hojas de la Planta/genética , Hojas de la Planta/crecimiento & desarrolloRESUMEN
Phosphate (P) and nitrogen (N) fertilization affect rice tillering, indicating that P- and N-regulated tiller growth has a crucial effect on grain yield. Cytokinins and strigolactones (SLs) promote and inhibit tiller bud outgrowth, respectively; however, the underlying mechanisms are unclear. In this study, tiller bud outgrowth and cytokinin fractions were evaluated in rice plants fertilized at different levels of P and N. Low phosphate or nitrogen (LP or LN) reduced rice tiller numbers and bud elongation, in line with low cytokinin levels in tiller buds and xylem sap as well as low TCSn:GUS expression, a sensitive cytokinin signal reporter, in the stem base. Furthermore, exogenous cytokinin (6-benzylaminopurin, 6-BA) administration restored bud length and TCSn:GUS activity in LP- and LN-treated plants to similar levels as control plants. The TCSn:GUS activity and tiller bud outgrowth were less affected by LP and LN supplies in SL-synthetic and SL-signaling mutants (d17 and d53) compared to LP- and LN-treated wild-type (WT) plants, indicating that SL modulate tiller bud elongation under LP and LN supplies by reducing the cytokinin levels in tiller buds. OsCKX9 (a cytokinin catabolism gene) transcription in buds and roots was induced by LP, LN supplies and by adding the SL analog GR24. A reduced response of cytokinin fractions to LP and LN supplies was observed in tiller buds and xylem sap of the d53 mutant compared to WT plants. These results suggest that cytokinin catabolism and transport are involved in SL-modulated rice tillering fueled by P and N fertilization.
Asunto(s)
Citocininas , Lactonas , Nitrógeno , Oryza , Fosfatos , Oryza/crecimiento & desarrollo , Oryza/metabolismo , Oryza/efectos de los fármacos , Citocininas/metabolismo , Nitrógeno/metabolismo , Lactonas/metabolismo , Lactonas/farmacología , Fosfatos/metabolismo , Transporte Biológico/efectos de los fármacos , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Proteínas de Plantas/metabolismoRESUMEN
Tetranychus urticae is an important pest that causes severe damage to a wide variety of plants and crops, leading to a substantial productivity loss. Previous research has been focused on plant defence response to T. urticae to improve plant resistance. However, plant growth, development and reproduction throughout the infestation process have not been previously studied. Through physiological, biochemical, transcriptomic and hormonomic evaluation, we uncover the molecular mechanisms directing the defence-growth trade-off established in Arabidopsis upon T. urticae infestation. Upon mite attack, plants suffer an adaptation process characterized by a temporal separation between the defence and growth responses. Jasmonic and salicylic acids regulate the main defence responses in combination with auxin and abscisic acid. However, while the reduction of both auxin signalling and gibberellin, cytokinin and brassinosteroid biosynthesis lead to initial growth arrest, increasing levels of growth hormones at later stages enables growth restart. These alterations lead to a plant developmental delay that impacts both seed production and longevity. We demonstrate that coordinated trade-offs determine plant adaptation and survival, revealing mite infestation has a long-lasting effect negatively impacting seed viability. This study provides additional tools to design pest management strategies that improve resistance without penalty in plant fitness.
Asunto(s)
Arabidopsis , Reguladores del Crecimiento de las Plantas , Tetranychidae , Animales , Reguladores del Crecimiento de las Plantas/metabolismo , Arabidopsis/fisiología , Arabidopsis/parasitología , Arabidopsis/genética , Tetranychidae/fisiología , Regulación de la Expresión Génica de las Plantas , Ácidos Indolacéticos/metabolismo , Ciclopentanos/metabolismo , Ácido Salicílico/metabolismo , Enfermedades de las Plantas/parasitología , Oxilipinas/metabolismo , Citocininas/metabolismo , Ácido Abscísico/metabolismoRESUMEN
Leaves play a crucial role in photosynthesis and respiration, ultimately affecting the final grain yield of crops, including wheat (Triticum aestivum L.); however, the molecular mechanisms underlying wheat leaf development remain largely unknown. Here, we isolated a narrow-leaf gene, TaWAK2-A, through a map-based cloning strategy. TaWAK2-A encodes a wall-associated kinase (WAK), for which a single Ala-to-Val amino acid substitution reduces the protein stability, leading to a narrow-leaf phenotype in wheat. Further investigation suggests that TaWAK2 directly interacts with and phosphorylates TaNAL1, a trypsin-like serine/cysteine protease. The phosphorylated TaNAL1 is then involved in the degradation of the zinc finger transcription factor TaDST, which acts as a repressor of leaf expansion by activating the expression of the cytokinin oxidase gene TaCKX9 and triggering in vivo cytokinin degradation. Therefore, our findings elucidate a signaling cascade involving TaWAK2-TaNAL1-TaDST that sheds light on the regulation of wheat leaf development.
Asunto(s)
Citocininas , Regulación de la Expresión Génica de las Plantas , Hojas de la Planta , Proteínas de Plantas , Transducción de Señal , Triticum , Triticum/genética , Triticum/metabolismo , Triticum/crecimiento & desarrollo , Hojas de la Planta/metabolismo , Hojas de la Planta/genética , Hojas de la Planta/crecimiento & desarrollo , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Citocininas/metabolismo , Factores de Transcripción/metabolismo , Factores de Transcripción/genética , Fosforilación , FenotipoRESUMEN
The shoot apical meristem (SAM) contains pluripotent stem cells that produce all the aerial parts of the plant. Stem cells undergo asymmetric cell divisions to self-renew and to produce differentiating cells. Our research focused on unraveling the mechanisms governing the specification of these two distinct cell fates following the stem cell division. For this purpose, we used the model organism Physcomitrium patens, which features a singular pluripotent stem cell known as the gametophore apical cell. We show that the activity of cytokinins, critical stem cell regulators, is restricted to the gametophore apical cell due to the specific localization of PpLOG, the enzyme responsible for cytokinin activation. In turn, PpTAW, which promotes differentiating cell identity of the merophyte, is excluded from the gametophore apical cell by the action of cytokinins. We propose a cytokinin-based model for the establishment of asymmetry in the pluripotent stem cell division.
Asunto(s)
Bryopsida , Citocininas , Proteínas de Plantas , Células Madre Pluripotentes , Citocininas/metabolismo , Células Madre Pluripotentes/metabolismo , Células Madre Pluripotentes/citología , Bryopsida/metabolismo , Bryopsida/citología , Proteínas de Plantas/metabolismo , Meristema/metabolismo , Meristema/citología , Diferenciación Celular , Regulación de la Expresión Génica de las PlantasRESUMEN
Shoot apical meristems (SAMs) continuously initiate organ formation and maintain pluripotency through dynamic genetic regulations and cell-to-cell communications. The activity of meristems directly affects the plant's structure by determining the number and arrangement of organs and tissues. We have taken a forward genetic approach to dissect the genetic pathway that controls cell differentiation around the SAM. The rice mutants, adaxial-abaxial bipolar leaf 1 and 2 (abl1 and abl2), produce an ectopic leaf that is fused back-to-back with the fourth leaf, the first leaf produced after embryogenesis. The abaxial-abaxial fusion is associated with the formation of an ectopic shoot meristem at the adaxial base of the fourth leaf primordium. We cloned the ABL1 and ABL2 genes of rice by mapping their chromosomal positions. ABL1 encodes OsHK6, a histidine kinase, and ABL2 encodes a transcription factor, OSHB3 (Class III homeodomain leucine zipper). Expression analyses of these mutant genes as well as OSH1, a rice ortholog of the Arabidopsis STM gene, unveiled a regulatory circuit that controls the formation of an ectopic meristem near the SAM at germination.
Asunto(s)
Citocininas , Regulación de la Expresión Génica de las Plantas , Meristema , Oryza , Hojas de la Planta , Proteínas de Plantas , Meristema/genética , Meristema/metabolismo , Oryza/genética , Oryza/metabolismo , Oryza/crecimiento & desarrollo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Citocininas/metabolismo , Citocininas/genética , Hojas de la Planta/metabolismo , Hojas de la Planta/genética , Hojas de la Planta/crecimiento & desarrollo , Mutación/genética , Genes de Plantas , Receptores de Superficie Celular/genética , Receptores de Superficie Celular/metabolismo , Proteínas de Homeodominio/metabolismo , Proteínas de Homeodominio/genéticaRESUMEN
KEY MESSAGE: The Osckx2 mutant accumulates cytokinin thereby enhancing panicle branching, grain yield, and drought tolerance, marked by improved survival rate, membrane integrity, and photosynthetic function. Cytokinins (CKs) are multifaceted hormones that regulate growth, development, and stress responses in plants. Cytokinins have been implicated in improved panicle architecture and grain yield; however, they are inactivated by the enzyme cytokinin oxidase (CKX). In this study, we developed a cytokinin oxidase 2 (Osckx2)-deficient mutant using CRISPR/Cas9 gene editing in indica rice and assessed its function under water-deficit and salinity conditions. Loss of OsCKX2 function increased grain number, secondary panicle branching, and overall grain yield through improved cytokinin content in the panicle tissue. Under drought conditions, the Osckx2 mutant conserved more water and demonstrated improved water-saving traits. Through reduced transpiration, Osckx2 mutants showed an improved survival response than the wild type to unset dehydration stress. Further, Osckx2 maintained chloroplast and membrane integrity and showed significantly improved photosynthetic function under drought conditions through enhanced antioxidant protection systems. The OsCKX2 function negatively affects panicle grain number and drought tolerance, with no discernible impact in response to salinity. The finding suggests the utility of the beneficial Osckx2 allele in breeding to develop climate-resilient, high-yielding cultivars for future food security.
Asunto(s)
Citocininas , Resistencia a la Sequía , Oryza , Oxidorreductasas , Proteínas de Plantas , Citocininas/metabolismo , Resistencia a la Sequía/genética , Grano Comestible/genética , Grano Comestible/crecimiento & desarrollo , Regulación de la Expresión Génica de las Plantas , Mutación/genética , Oryza/genética , Oryza/fisiología , Oryza/crecimiento & desarrollo , Oryza/enzimología , Oxidorreductasas/genética , Oxidorreductasas/metabolismo , Fotosíntesis/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Modificadas Genéticamente , Estrés Fisiológico/genéticaRESUMEN
The cytokinin response factors (CRFs) are pivotal players in regulating plant growth, development, and responses to diverse stresses. Despite their significance, comprehensive information on CRF genes in the primary food crop, maize, remains scarce. In this study, a genome-wide analysis of CRF genes in maize was conducted, resulting in the identification of 12 members. Subsequently, we assessed the chromosomal locations, gene duplication events, evolutionary relationships, conserved motifs, and gene structures of all ZmCRF members. Analysis of ZmCRF promoter regions indicated the presence of cis-regulatory elements associated with plant growth regulation, hormone response, and various abiotic stress responses. The expression patterns of maize CRF genes, presented in heatmaps, exhibited distinctive patterns of tissue specificity and responsiveness to multiple abiotic stresses. qRT-PCR experiments were conducted on six selected genes and confirmed the involvement of ZmCRF genes in the plant's adaptive responses to diverse environmental challenges. In addition, ZmCRF9 was demonstrated to positively regulate cold and salt tolerance. Ultimately, we explored the putative interaction partners of ZmCRF proteins. In summary, this systematic overview and deep investigation of ZmCRF9 provides a solid foundation for further exploration into how these genes contribute to the complex interplay of plant growth, development, and responses to stress.
Asunto(s)
Regulación de la Expresión Génica de las Plantas , Familia de Multigenes , Proteínas de Plantas , Estrés Fisiológico , Zea mays , Zea mays/genética , Zea mays/metabolismo , Estrés Fisiológico/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Filogenia , Genoma de Planta , Regiones Promotoras Genéticas , Citocininas/metabolismo , Estudio de Asociación del Genoma Completo , Duplicación de GenRESUMEN
Tension wood is a specialized xylem tissue associated with gravitropism in angiosperm trees. However, few regulators of tension wood formation have been identified. The molecular mechanisms underpinning tension wood formation remain elusive. Here, we report that a Populus KNOTTED-like homeobox gene, PagKNAT2/6b, is involved in tension wood formation and gravity response. Transgenic poplar plants overexpressing PagKNAT2/6b displayed more sensitive gravitropism than controls, as indicated by increased stem curvature. Microscopic examination revealed greater abundance of fibre cells with a gelatinous cell wall layer (G-layer) and asymmetric growth of secondary xylem in PagKNAT2/6b overexpression lines. Conversely, PagKNAT2/6b dominant repression plants exhibited decreased tension wood formation and reduced response to gravity stimulation. Moreover, sensitivity to gravity stimulation showed a negative relationship with development stage. Expression of genes related to growth and senescence was affected in PagKNAT2/6b transgenic plants. More importantly, transcription activation and electrophoretic mobility shift assays suggested that PagKNAT2/6b promotes the expression of cytokinin metabolism genes. Consistently, cytokinin content was increased in PagKNAT2/6b overexpression plants. Therefore, PagKNAT2/6b is involved in gravitropism and tension wood formation, likely via modulation of cytokinin metabolism.
Asunto(s)
Citocininas , Gravitropismo , Proteínas de Plantas , Plantas Modificadas Genéticamente , Populus , Madera , Gravitropismo/fisiología , Citocininas/metabolismo , Populus/genética , Populus/crecimiento & desarrollo , Populus/fisiología , Populus/metabolismo , Madera/crecimiento & desarrollo , Madera/fisiología , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Modificadas Genéticamente/genética , Xilema/metabolismo , Xilema/fisiología , Xilema/crecimiento & desarrollo , Xilema/genética , Regulación de la Expresión Génica de las Plantas , Proteínas de Homeodominio/genética , Proteínas de Homeodominio/metabolismoRESUMEN
Cytokinins (CKs) are phytohormones structurally similar to purines that play important roles in various aspects of plant physiology and development. The local and long-distance distribution of CKs is very important to control their action throughout the plant body. Over the past decade, several novel CK transporters have been described, many of which have been linked to a physiological function rather than simply their ability to transport the hormone in vitro. Purine permeases, equilibrative nucleotide transporters and ATP-binding cassette transporters are involved in the local and long-range distribution of CK. In addition, members of the Arabidopsis AZA-GUANINE RESISTANT (AZG) protein family, AZG1 and AZG2, have recently been shown to mediate CK uptake at the plasma membrane and endoplasmic reticulum. Despite sharing â¼50% homology, AZG1 and AZG2 have unique transport mechanisms, tissue-specific expression patterns, and subcellular localizations that underlie their distinct physiological functions. AZG2 is expressed in a small group of cells in the overlying tissue around the lateral root primordia, where its expression is induced by auxins and it is involved in the regulation of lateral root growth. AZG1 is ubiquitously expressed, with high levels in the division zone of the root apical meristem. Here, it binds and stabilises the auxin efflux carrier PIN1, thereby shaping root architecture, particularly under salt stress. This review highlights the latest findings on the protein properties, transport mechanisms and cellular functions of this new family of CK transporters and discusses perspectives for future research in this field.
Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Citocininas , Proteínas de Transporte de Membrana , Citocininas/metabolismo , Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Proteínas de Transporte de Membrana/metabolismo , Transporte Biológico , Regulación de la Expresión Génica de las Plantas , Raíces de Plantas/metabolismo , Raíces de Plantas/crecimiento & desarrollo , Reguladores del Crecimiento de las Plantas/metabolismoRESUMEN
Cytokinin (CK) is a key plant hormone, but one whose effects are often misunderstood, partly due to reliance on older data from before the molecular genetic age of plant science. In this mini-review, we examine the role of CK in controlling the reproductive shoot architecture of flowering plants. We begin with a long overdue re-examination of the role of CK in shoot branching, and discuss the relatively paucity of genetic evidence that CK does play a major role in this process. We then examine the role of CK in determining the number of inflorescences, flowers, fruit and seed that plants initiate during reproductive development, and how these are arranged in space and time. The genetic evidence for a major role of CK in controlling these processes is much clearer, and CK has profound effects in boosting the size and number of most reproductive structures. Conversely, the attenuation of CK levels during the reproductive phase likely contributes to reduced organ size seen later in flowering, and the ultimate arrest of inflorescence meristems during end-of-flowering. We finish by discussing how this information can potentially be used to improve crop yields.
Asunto(s)
Citocininas , Brotes de la Planta , Citocininas/metabolismo , Brotes de la Planta/crecimiento & desarrollo , Brotes de la Planta/metabolismo , Flores/crecimiento & desarrollo , Reproducción/fisiología , Regulación de la Expresión Génica de las Plantas , Meristema/crecimiento & desarrollo , Meristema/metabolismo , Reguladores del Crecimiento de las Plantas/metabolismoRESUMEN
Transcription factors in coordination with phytohormones form an intricate regulatory network modulating vital cellular mechanisms like development, growth and senescence in plants. In this study, we have functionally characterized the transcription factor OsNAC121 by developing gene silencing and overexpressing transgenic rice plants, followed by detailed analyses of the plant architecture. Transgenic lines exhibited remodelling in crown root development, lateral root structure and density, tiller height and number, panicle and grain morphologies, underpinning the imbalanced auxin: cytokinin ratio due to perturbed auxin transportation. Application of cytokinin, auxin and abscisic acid increased OsNAC121 gene expression nearly 17-, 6- and 91-folds, respectively. qRT-PCR results showed differential expressions of auxin and cytokinin pathway genes, implying their altered levels. A 47-fold higher expression level of OsNAC121 during milky stage in untransformed rice, compared to 14-day old shoot tissue, suggests its crucial role in grain filling; as evidenced by a large number of undeveloped grains produced by the gene silenced lines. Crippled gravitropic response by the transgenic plants indicates their impaired auxin transport. Bioinformatics revealed that OsNAC121 interacts with co-repressor (TOPLESS) proteins and forms a part of the inhibitor complex OsIAA10, an essential core component of auxin signalling pathway. Therefore, OsNAC121 emerges as an important regulator of various aspects of plant architecture through modulation of crosstalk between auxin and cytokinin, altering their concentration gradient in the meristematic zones, and consequently modifying different plant organogenesis processes.
Asunto(s)
Citocininas , Regulación de la Expresión Génica de las Plantas , Ácidos Indolacéticos , Oryza , Reguladores del Crecimiento de las Plantas , Proteínas de Plantas , Raíces de Plantas , Plantas Modificadas Genéticamente , Factores de Transcripción , Oryza/genética , Oryza/crecimiento & desarrollo , Oryza/metabolismo , Raíces de Plantas/crecimiento & desarrollo , Raíces de Plantas/genética , Raíces de Plantas/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Ácidos Indolacéticos/metabolismo , Citocininas/metabolismo , Reguladores del Crecimiento de las Plantas/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Ácido Abscísico/metabolismo , Grano Comestible/genética , Grano Comestible/crecimiento & desarrollo , Grano Comestible/metabolismoRESUMEN
MAIN CONCLUSION: We studied the D3-type cyclin function during gynoecium development in Arabidopsis and how they are related to the hormone cytokinin and the transcription factor SPATULA. Growth throughout the life of plants is sustained by cell division and differentiation processes in meristematic tissues. In Arabidopsis, gynoecium development implies a multiphasic process where the tissues required for pollination, fertilization, and seed development form. The Carpel Margin Meristem (CMM) is a mass of undifferentiated cells that gives rise to the gynoecium internal tissues, such as septum, ovules, placenta, funiculus, transmitting tract, style, and stigma. Different genetic and hormonal factors, including cytokinin, control the CMM function. Cytokinin regulates the cell cycle transitions through the activation of cell cycle regulators as cyclin genes. D3-type cyclins are expressed in proliferative tissues, favoring the mitotic cell cycle over the endoreduplication. Though the role of cytokinin in CMM and gynoecium development is highly studied, its specific role in regulating the cell cycle in this tissue remains unclear. Additionally, despite extensive research on the relationship between CYCD3 genes and cytokinin, the regulatory mechanism that connects them remains elusive. Here, we found that D3-type cyclins are expressed in proliferative medial and lateral tissues. Conversely, the depletion of the three CYCD3 genes showed that they are not essential for gynoecium development. However, the addition of exogenous cytokinin showed that they could control the division/differentiation balance in gynoecium internal tissues and outgrowths. Finally, we found that SPATULA can be a mechanistic link between cytokinin and the D3-type cyclins. The data suggest that the role of D3-type cyclins in gynoecium development is related to the cytokinin response, and they might be activated by the transcription factor SPATULA.
Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico , Citocininas , Flores , Regulación de la Expresión Génica de las Plantas , Citocininas/metabolismo , Arabidopsis/genética , Arabidopsis/crecimiento & desarrollo , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Flores/crecimiento & desarrollo , Flores/genética , Flores/metabolismo , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/metabolismo , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética , Ciclina D3/metabolismo , Ciclina D3/genética , Meristema/genética , Meristema/crecimiento & desarrollo , Meristema/metabolismo , CiclinasRESUMEN
BACKGROUND: In plants, the leaf functions as a solar panel, where photosynthesis converts carbon dioxide and water into carbohydrates and oxygen. In soybean, leaf type traits, including leaf shape, leaf area, leaf width, and leaf width so on, are considered to be associated with yield. In this study, we performed morphological characterization, transcriptome analysis, and endogenous hormone analysis of a rolled and narrow leaf mutant line (rl) in soybean. RESULTS: Compared with wild type HX3, mutant line rl showed rolled and narrower leaflet, and smaller leaf, meanwhile rl also performed narrower pod and narrower seed. Anatomical analysis of leaflet demonstrated that cell area of upper epidermis was bigger than the cell area of lower epidermis in rl, which may lead rolled and narrow leaf. Transcriptome analysis revealed that several cytokinin oxidase/dehydrogenase (CKX) genes (Glyma.06G028900, Glyma.09G225400, Glyma.13G104700, Glyma.14G099000, and Glyma.17G054500) were up-regulation dramatically, which may cause lower cytokinin level in rl. Endogenous hormone analysis verified that cytokinin content of rl was lower. Hormone treatment results indicated that 6-BA rescued rolled leaf enough, rescued partly narrow leaf. And after 6-BA treatment, the cell area was similar between upper epidermis and lower epidermis in rl. Although IAA content and ABA content were reduced in rl, but exogenous IAA and ABA didn't affect leaf type of HX3 and rl. CONCLUSIONS: Our results suggest abnormal cytokinin metabolism caused rolled and narrow leaf in rl, and provide valuable clues for further understanding the mechanisms underlying leaf development in soybean.
Asunto(s)
Perfilación de la Expresión Génica , Glycine max , Hojas de la Planta , Glycine max/genética , Glycine max/crecimiento & desarrollo , Glycine max/anatomía & histología , Glycine max/metabolismo , Hojas de la Planta/genética , Hojas de la Planta/crecimiento & desarrollo , Hojas de la Planta/anatomía & histología , Transcriptoma , Mutación , Regulación de la Expresión Génica de las Plantas , Reguladores del Crecimiento de las Plantas/metabolismo , Citocininas/metabolismo , FenotipoRESUMEN
BACKGROUND: Kentucky bluegrass (Poa pratensis L.) panicle development is a coordinated process of cell proliferation and differentiation with distinctive phases and architectural changes that are pivotal to determine seed yield. Cytokinin (CK) is a key factor in determining seed yield that might underpin the second "Green Revolution". However, whether there is a difference between endogenous CK content and seed yields of Kentucky bluegrass, and how CK-related genes are expressed to affect enzyme regulation and downstream seed yield in Kentucky bluegrass remains enigmatic. RESULTS: In order to establish a potential link between CK regulation and seed yield, we dissected and characterized the Kentucky bluegrass young panicle, and determined the changes in nutrients, 6 types of endogenous CKs, and 16 genes involved in biosynthesis, activation, inactivation, re-activation and degradation of CKs during young panicle differentiation of Kentucky bluegrass. We found that high seed yield material had more meristems compared to low seed yield material. Additionally, it was found that seed-setting rate (SSR) and lipase activity at the stage of spikelet and floret primordium differentiation (S3), as well as 1000-grain weight (TGW) and zeatin-riboside (ZR) content at the stages of first bract primordium differentiation (S1) and branch primordium differentiation (S2) showed a significantly positive correlation in the two materials. And zeatin, ZR, dihydrozeatin riboside, isopentenyl adenosine and isopentenyl adenosine riboside contents were higher in seed high yield material than those in seed low yield material at S3 stage. Furthermore, the expressions of PpITP3, PpITP5, PpITP8 and PpLOG1 were positively correlated with seed yield, while the expressions of PpCKX2, PpCKX5 and PpCKX7 were negatively correlated with seed yield in Kentucky bluegrass. CONCLUSIONS: Overall, our study established a relationship between CK and seed yield in Kentucky bluegrass. Perhaps we can increase SSR and TGW by increasing lipase activity and ZR content. Of course, using modern gene editing techniques to manipulate CK related genes such as PpITP3/5/8, PpLOG1 and PpCKX2/5/7, will be a more direct and effective method in Kentucky bluegrass, which requires further trial validation.
Asunto(s)
Citocininas , Regulación de la Expresión Génica de las Plantas , Poa , Semillas , Citocininas/metabolismo , Semillas/crecimiento & desarrollo , Semillas/genética , Poa/genética , Poa/crecimiento & desarrollo , Poa/metabolismo , Reguladores del Crecimiento de las Plantas/metabolismo , Genes de PlantasRESUMEN
Host plants benefit from legume root nodule symbiosis with nitrogen-fixing bacteria under nitrogen-limiting conditions. In this interaction, the hosts must regulate nodule numbers and distribution patterns to control the degree of symbiosis and maintain root growth functions. The host response to symbiotic bacteria occurs discontinuously but repeatedly at the region behind the tip of the growing roots. Here, live-imaging and transcriptome analyses revealed oscillating host gene expression with approximately 6-hour intervals upon bacterial inoculation. Cytokinin response also exhibited a similar oscillation pattern. Cytokinin signaling is crucial to maintaining the periodicity, as observed in cytokinin receptor mutants displaying altered infection foci distribution. This periodic regulation influences the size of the root region responsive to bacteria, as well as the nodulation process progression.
Asunto(s)
Citocininas , Regulación de la Expresión Génica de las Plantas , Interacciones Microbiota-Huesped , Lotus , Mesorhizobium , Nodulación de la Raíz de la Planta , Nódulos de las Raíces de las Plantas , Simbiosis , Citocininas/metabolismo , Perfilación de la Expresión Génica , Lotus/genética , Lotus/crecimiento & desarrollo , Lotus/metabolismo , Mutación , Nódulos de las Raíces de las Plantas/crecimiento & desarrollo , Nódulos de las Raíces de las Plantas/microbiología , Transducción de Señal , Mesorhizobium/genética , Mesorhizobium/fisiologíaRESUMEN
Here, cytosine methylation in the whole genome of pear flower buds was mapped at a single-base resolution. There was 19.4% methylation across all sequenced C sites in the Pyrus pyrifolia cultivar 'Sucui 1' flower bud genome. Meantime, the CG, CHG, and CHH sequence contexts (where H = A, T or C) exhibited 47.4%, 33.3%, and 11.9% methylation, respectively. Methylation in different gene regions was revealed through combining methylome and transcriptome analysis, which presented various transcription trends. Genes with methylated promoters exhibited lower expression levels than genes with non-methylated promoters, while body-methylated genes displayed an obvious negative correlation with their transcription levels. The methylation profiles of auxin- and cytokinin-related genes were estimated. And some of them proved to be hypomethylated, with increased transcription levels, in wizened buds. More specifically, the expression of the genes PRXP73, CYP749A22, and CYP82A3 was upregulated as a result of methylation changes in their promoters. Finally, auxin and cytokinin concentrations were higher in wizened flower buds than in normal buds. The exogenous application of paclobutrazol (PP333) in the field influenced the DNA methylation status of some genes and changed their expression level, reducing the proportion of wizened flower buds in a concentration-dependent manner. Overall, our results demonstrated the relationship between DNA methylation and gene expression in wizened flower buds of P. pyrifolia cultivar 'Sucui 1', which was associated with changes in auxin and cytokinin concentrations.
Asunto(s)
Metilación de ADN , Epigenoma , Flores , Perfilación de la Expresión Génica , Regulación de la Expresión Génica de las Plantas , Pyrus , Flores/genética , Flores/crecimiento & desarrollo , Flores/metabolismo , Pyrus/genética , Pyrus/crecimiento & desarrollo , Pyrus/metabolismo , Regiones Promotoras Genéticas , Transcriptoma , Ácidos Indolacéticos/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Citocininas/metabolismoRESUMEN
BACKGROUND: Kale, a versatile cruciferous crop, valued for its pro-health benefits, stress resistance, and potential applications in forage and cosmetics, holds promise for further enhancement of its bioactive compounds through in vitro cultivation methods. Micropropagation techniques use cytokinins (CKs) which are characterized by various proliferative efficiency. Despite the extensive knowledge regarding CKs, there remains a gap in understanding their role in the physiological mechanisms. That is why, here we investigated the effects of three CKs - kinetin (Kin), 6-benzylaminopurine (BAP), and 2-isopentenyladenine (2iP) - on kale physiology, antioxidant status, steroidal metabolism, and membrane integrity under in vitro cultivation. RESULTS: Our study revealed that while BAP and 2iP stimulated shoot proliferation, they concurrently diminished pigment levels and photosynthetic efficiency. Heightened metabolic activity in response to all CKs was reflected by increased respiratory rate. Despite the differential burst of ROS, the antioxidant properties of kale were associated with the upregulation of guaiacol peroxidase and the scavenging properties of ascorbate rather than glutathione. Notably, CKs fostered the synthesis of sterols, particularly sitosterol, pivotal for cell proliferation and structure of membranes which are strongly disrupted under the action of BAP and 2iP possibly via pathway related to phospholipase D and lipoxygenase which were upregulated. Intriguingly, both CKs treatment spurred the accumulation of sitostenone, known for its ROS scavenging and therapeutic potential. The differential effects of CKs on brassicasterol levels and brassinosteroid (BRs) receptor suggest potential interactions between CKs and BRs. CONCLUSION: Based on the presented results we conclude that the effect evoked by BAP and 2iP in vitro can improve the industrial significance of kale because this treatment makes possible to control proliferation and/or biosynthesis routes of valuable beneficial compounds. Our work offers significant insights into the nuanced effects of CKs on kale physiology and metabolism, illuminating potential avenues for their application in plant biotechnology and medicinal research.