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1.
Braz J Biol ; 84: e280778, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38922193

RESUMEN

Despite being valuable for producing a natural sweetener Curculin, Curculigo latifolia has a low growth and difficult to domestificate. So, to solve this problem, propagation on in vitro culture will be an alternative method to propagated this spesies under different cytokinins and light condition. Cytokinins and light has major role in organogenesis, growth and gene expression of many species. Thus, in this study, we aimed to improve the Curculigo latifolia growth on in vitro condition and expression of curculin gene by combining cytokinins addition and different light exposure. Four weeks seedlings were sub-cultured into medium (MS free hormone) containing 3 mg/L benzyladenine (BA) and various concentrations of meta-Topolin (mT) including 0.1 mg/L, 0.5 mg/L, and 5 mg/L. The cultures then incubated under different light types (red, blue, white LED lights and white fluorescence light) with 16-h light/ 18-h dark photoperiod for 14 weeks at 25 ± 2°C. Several parameters, including plant height, leaf number, chlorophyll contents, stomatal structure, and density and curculin expression, were observed every week. Unexpectedly, our results showed that C. latifolia growth displayed significant improvement when it was treated under white LED light without any additional cytokinins. In sum, white LED light further improves plantlets phenotype, such as plant height, leaf number, chlorophyll production, and stomatal number and structure, whereas, red LED light lead to a decreased phenotypes but increase the curculin gene expression.


Asunto(s)
Curculigo , Citocininas , Luz , Reguladores del Crecimiento de las Plantas , Citocininas/farmacología , Curculigo/genética , Reguladores del Crecimiento de las Plantas/farmacología , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos
2.
Viruses ; 16(6)2024 May 23.
Artículo en Inglés | MEDLINE | ID: mdl-38932119

RESUMEN

Cytokinins (CKs) are a group of N6-substituted signaling molecules whose biosynthesis and metabolism have been documented in all kingdoms of life, including vertebrates. While their biological relevance in vertebrate systems continues to be elucidated, they have broadly been documented with therapeutic effects in exogenous applications. In this study, we evaluated the virostatic potential of four types of CKs including, N6-isopentenyladenine (iP), N6-isopentenyladenosine (iPR), N6-isopentenyladenosine-5'monophosphate (iPMP), and 2-methylthiol-N6-isopentenyladenosine (2MeSiPR) against the ranavirus type species, frog virus 3 (FV3). Following concurrent treatment and infection, iP and iPR reduced viral replication by 33.8% and 59.6%, respectively, in plaque formation assays. A decrease in viral replication was also observed when CK exposure was limited to 12 h prior to infection, where iP and iPR reduced viral replication by 31% and 23.75%, respectively. Treatment with iP and iPR was also marked by 48% and 60% decreases in viral load over 72 h, respectively, as measured in single step growth curves. Plaque morphology was altered in vitro, as iP and iPR treatment increased plaque area by 83% and 112% with lytic zone formation also becoming more prevalent in corresponding treatments. Treatment with iPMP and 2MeSiPR resulted in no effect on viral kinetics in vitro. The results of this study are the first to provide evidence of CK antiviral activity against a DNA virus and highlight the importance of their structure for therapeutic investigations.


Asunto(s)
Antivirales , Citocininas , Ranavirus , Ensayo de Placa Viral , Replicación Viral , Replicación Viral/efectos de los fármacos , Animales , Antivirales/farmacología , Ranavirus/fisiología , Ranavirus/efectos de los fármacos , Citocininas/farmacología , Citocininas/metabolismo , Línea Celular
3.
Int J Mol Sci ; 25(11)2024 Jun 03.
Artículo en Inglés | MEDLINE | ID: mdl-38892338

RESUMEN

The elongation of the mesocotyl plays an important role in the emergence of maize deep-sowing seeds. This study was designed to explore the function of exogenous salicylic acid (SA) and 6-benzylaminopurine (6-BA) in the growth of the maize mesocotyl and to examine its regulatory network. The results showed that the addition of 0.25 mmol/L exogenous SA promoted the elongation of maize mesocotyls under both 3 cm and 15 cm deep-sowing conditions. Conversely, the addition of 10 mg/L exogenous 6-BA inhibited the elongation of maize mesocotyls. Interestingly, the combined treatment of exogenous SA-6-BA also inhibited the elongation of maize mesocotyls. The longitudinal elongation of mesocotyl cells was the main reason affecting the elongation of maize mesocotyls. Transcriptome analysis showed that exogenous SA and 6-BA may interact in the hormone signaling regulatory network of mesocotyl elongation. The differential expression of genes related to auxin (IAA), jasmonic acid (JA), brassinosteroid (BR), cytokinin (CTK) and SA signaling pathways may be related to the regulation of exogenous SA and 6-BA on the growth of mesocotyls. In addition, five candidate genes that may regulate the length of mesocotyls were screened by Weighted Gene Co-Expression Network Analysis (WGCNA). These genes may be involved in the growth of maize mesocotyls through auxin-activated signaling pathways, transmembrane transport, methylation and redox processes. The results enhance our understanding of the plant hormone regulation of mesocotyl growth, which will help to further explore and identify the key genes affecting mesocotyl growth in plant hormone signaling regulatory networks.


Asunto(s)
Compuestos de Bencilo , Regulación de la Expresión Génica de las Plantas , Reguladores del Crecimiento de las Plantas , Purinas , Ácido Salicílico , Zea mays , Zea mays/crecimiento & desarrollo , Zea mays/efectos de los fármacos , Zea mays/genética , Zea mays/metabolismo , Ácido Salicílico/farmacología , Ácido Salicílico/metabolismo , Purinas/farmacología , Compuestos de Bencilo/farmacología , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Reguladores del Crecimiento de las Plantas/farmacología , Reguladores del Crecimiento de las Plantas/metabolismo , Oxilipinas/farmacología , Citocininas/metabolismo , Citocininas/farmacología , Semillas/efectos de los fármacos , Semillas/crecimiento & desarrollo , Semillas/genética , Perfilación de la Expresión Génica , Transducción de Señal/efectos de los fármacos , Ácidos Indolacéticos/farmacología , Ácidos Indolacéticos/metabolismo , Ciclopentanos/farmacología
4.
Plant Physiol ; 195(3): 2094-2110, 2024 Jun 28.
Artículo en Inglés | MEDLINE | ID: mdl-38588029

RESUMEN

Salt gland is an epidermal Na+ secretory structure that enhances salt resistance in the recretohalophyte sea lavender (Limonium bicolor). To elucidate the salt gland development trajectory and related molecular mechanisms, we performed single-cell RNA sequencing of L. bicolor protoplasts from young leaves at salt gland initiation and differentiation stages. Dimensionality reduction analyses defined 19 transcriptionally distinct cell clusters, which were assigned into 4 broad populations-promeristem, epidermis, mesophyll, and vascular tissue-verified by in situ hybridization. Cytokinin was further proposed to participate in salt gland development by the expression patterns of related genes and cytological evidence. By comparison analyses of Single-cell RNA sequencing with exogenous application of 6-benzylaminopurine, we delineated 5 salt gland development-associated subclusters and defined salt gland-specific differentiation trajectories from Subclusters 8, 4, and 6 to Subcluster 3 and 1. Additionally, we validated the participation of TRIPTYCHON and the interacting protein Lb7G34824 in salt gland development, which regulated the expression of cytokinin metabolism and signaling-related genes such as GLABROUS INFLORESCENCE STEMS 2 to maintain cytokinin homeostasis during salt gland development. Our results generated a gene expression map of young leaves at single-cell resolution for the comprehensive investigation of salt gland determinants and cytokinin participation that helps elucidate cell fate determination during epidermis formation and evolution in recretohalophytes.


Asunto(s)
Citocininas , Regulación de la Expresión Génica de las Plantas , Plumbaginaceae , Citocininas/metabolismo , Citocininas/farmacología , Plumbaginaceae/genética , Plumbaginaceae/crecimiento & desarrollo , Plumbaginaceae/metabolismo , Hojas de la Planta/crecimiento & desarrollo , Hojas de la Planta/genética , Hojas de la Planta/metabolismo , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética
5.
J Ethnopharmacol ; 330: 118199, 2024 Aug 10.
Artículo en Inglés | MEDLINE | ID: mdl-38631486

RESUMEN

ETHNOPHARMACOLOGICAL RELEVANCE: Nocardiosis is an uncommon infectious disease that bears certain similarities to tuberculosis, with a continuous increase in its incidence and a poor prognosis. In traditional Chinese medicine, the leaves of Cajanus cajan (L.) Millsp. are employed to treat wounds, malaria, coughs, and abdominal pain. AIM OF THE STUDY: In this study, we investigated the effects and mechanisms of longistylin A (LGA), a natural stilbene isolated from C. cajan, as a potential antibiotic against nocardiosis. MATERIALS AND METHODS: LGA was isolated from the leaves of C. cajan and assessed using a minimum bactericidal concentration (MBC) determination against Nocardia seriolae. Multi-omics analysis encompassing genes, proteins, and metabolites was conducted to investigate the impact of LGA treatment on N. seriolae. Additionally, quantitative analysis of 40 cytokinins in N. seriolae mycelium was performed to assess the specific effects of LGA treatment on cytokinin levels. Cryo-scanning electron microscopy was utilized to examine morphological changes induced by LGA treatment, particularly in the presence of exogenous trans-zeatin-O-glucoside (tZOG). The therapeutic effect of LGA was investigated by feeding N. seriolae-infected largemouth bass. RESULTS: LGA exhibited significant efficacy against N. seriolae, with MBC value of 2.56 µg/mL. Multi-omics analysis revealed that LGA disrupted glycerophospholipid metabolism and hormone biosynthesis by notably reducing the expression of glycerol-3-phosphate dehydrogenase and calmodulin-like protein. Treatment with LGA markedly disrupted 12 distinct cytokinins in N. seriolae mycelium. Additionally, the addition of exogenous tZOG counteracted the inhibitory effects of LGA on filamentous growth, resulting in mycelial elongation and branching. Furthermore, LGA treatment improved the survival rate of largemouth bass infected with N. seriolae. CONCLUSIONS: We found for the first time that LGA from C. cajan exhibited significant efficacy against N. seriolae by interfering with glycerophospholipid metabolism and cytokinin biosynthesis.


Asunto(s)
Antibacterianos , Cajanus , Citocininas , Glicerofosfolípidos , Nocardia , Nocardia/metabolismo , Nocardia/efectos de los fármacos , Citocininas/farmacología , Citocininas/biosíntesis , Citocininas/metabolismo , Glicerofosfolípidos/metabolismo , Glicerofosfolípidos/biosíntesis , Antibacterianos/farmacología , Pruebas de Sensibilidad Microbiana , Hojas de la Planta
6.
Plant Cell Environ ; 47(7): 2597-2613, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38549236

RESUMEN

Plant leaves contain multiple cell types which achieve distinct characteristics whilst still coordinating development within the leaf. The bundle sheath possesses larger individual cells and lower chloroplast content than the adjacent mesophyll, but how this morphology is achieved remains unknown. To identify regulatory mechanisms determining bundle sheath cell morphology we tested the effects of perturbing environmental (light) and endogenous signals (hormones) during leaf development of Oryza sativa (rice). Total chloroplast area in bundle sheath cells was found to increase with cell size as in the mesophyll but did not maintain a 'set-point' relationship, with the longest bundle sheath cells demonstrating the lowest chloroplast content. Application of exogenous cytokinin and gibberellin significantly altered the relationship between cell size and chloroplast biosynthesis in the bundle sheath, increasing chloroplast content of the longest cells. Delayed exposure to light reduced the mean length of bundle sheath cells but increased corresponding leaf length, whereas premature light reduced final leaf length but did not affect bundle sheath cells. This suggests that the plant hormones cytokinin and gibberellin are regulators of the bundle sheath cell-chloroplast relationship and that final bundle sheath length may potentially be affected by light-mediated control of exit from the cell cycle.


Asunto(s)
Cloroplastos , Citocininas , Giberelinas , Luz , Oryza , Reguladores del Crecimiento de las Plantas , Hojas de la Planta , Oryza/crecimiento & desarrollo , Oryza/efectos de la radiación , Oryza/citología , Hojas de la Planta/crecimiento & desarrollo , Hojas de la Planta/efectos de la radiación , Citocininas/metabolismo , Citocininas/farmacología , Giberelinas/metabolismo , Reguladores del Crecimiento de las Plantas/metabolismo , Cloroplastos/metabolismo , Forma de la Célula/efectos de la radiación , Factores de Tiempo , Tamaño de la Célula/efectos de la radiación
7.
J Hazard Mater ; 468: 133134, 2024 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-38387171

RESUMEN

The rising heavy metal contamination of soils imposes toxic impacts on plants as well as other life forms. One such highly toxic and carcinogenic heavy metal is hexavalent chromium [Cr(VI)] that has been reported to prominently retard the plant growth. The present study investigated the potential of silicon (Si, 10 µM) to alleviate the toxicity of Cr(VI) (25 µM) on roots of wheat (Triticum aestivum L.) seedlings. Application of Si to Cr(VI)-stressed wheat seedlings improved their overall growth parameters. This study also reveals the involvement of two phytohormones, namely auxin and cytokinin and their crosstalk in Si-mediated mitigation of the toxic impacts of Cr(VI) in wheat seedlings. The application of cytokinin alone to wheat seedlings under Cr(VI) stress reduced the intensity of toxic effects of Cr(VI). In combination with Si, cytokinin application to Cr(VI)-stressed wheat seedlings significantly minimized the decrease induced by Cr(VI) in different parameters such as root-shoot length (10.8% and 13%, respectively), root-shoot fresh mass (11.3% and 10.1%, respectively), and total chlorophyll and carotenoids content (13.4% and 6.8%, respectively) with respect to the control. This treatment also maintained the regulation of proline metabolism (proline content, and P5CS and PDH activities), ascorbate-glutathione (AsA-GSH) cycle and nutrient homeostasis. The protective effect of Si and cytokinin against Cr(VI) stress was minimized upon supplementation of an inhibitor of polar auxin transport- 2,3,5-triiodobenzoic acid (TIBA) which suggested a potential involvement of auxin in Si and cytokinin-mediated mitigation of Cr(VI) toxicity. The exogenous addition of a natural auxin - indole-3-acetic acid (IAA) confirmed auxin is an active member of a signaling cascade along with cytokinin that aids in Si-mediated Cr(VI) toxicity alleviation as IAA application reversed the negative impacts of TIBA on wheat roots treated with Cr(VI), cytokinin and Si. The results of this research are also confirmed by the gene expression analysis conducted for nutrient transporters (Lsi1, CCaMK, MHX, SULT1 and ZIP1) and enzymes involved in the AsA-GSH cycle (APX, GR, DHAR and MDHAR). The overall results of this research indicate towards possible induction of a crosstalk between cytokinin and IAA upon Si supplementation which in turn stimulates physiological, biochemical and molecular changes to exhibit protective effects against Cr(VI) stress. Further, the information obtained suggests probable employment of Si, cytokinin and IAA alone or combined in agriculture to maintain plant productivity under Cr(VI) stress and data regarding expression of key genes can be used to develop new crop varieties with enhanced resistance against Cr(VI) stress together with its reduced load in seedlings.


Asunto(s)
Plantones , Ácidos Triyodobenzoicos , Triticum , Triticum/metabolismo , Silicio/farmacología , Citocininas/farmacología , Citocininas/metabolismo , Antioxidantes/metabolismo , Cromo/toxicidad , Cromo/metabolismo , Ácidos Indolacéticos/farmacología , Prolina/metabolismo , Prolina/farmacología , Estrés Oxidativo
8.
Braz J Biol ; 83: e275635, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-38126635

RESUMEN

Bioavailability of nutrients, the scarcity of synthetic fertilisers, and the rising cost of fuel have all contributed to an increase in production costs, which has in turn reduced crop productivity and led scientists to seek out new methods to ensure high-quality output. In this context, various cytokinins dosages were tested in Peru to see whether they affected the quality of caigua, in an effort to address these issues. To mitigate these problems, a pot experiment was carried out to check the effects of various doses of cytokinin in the quality of caigua in Peru. The experiment consisted of 5 treatments including (0, 50, 100, 150 and 200 mL of cytokinin) by using (Anthesis Plus per 200 L of water) as a source, each with three replicates and placed following a randomized complete block design (RCBD). Treatment with 100 mL of cytokinins foliar analysis resulted in a caigua length of 18.9 cm, an increase in diameter of 5.65 cm, and an improvement in pulp thickness of 7.60 millimeters. Physiological parameters of caigua plants taken after 45 days of sowing were considerably improved with the same treatment. Similarly, N, K and Zn concentration in leaf was higher in case of 100 mL of cytokinins foliar analysis. Therefore, policymakers must advise using the recommended quantity of cytokinins to bring about regime transition, and formers can gain by injecting 100 mL of cytokinins to boost production and the economy. It was concluded that the adequate dose of cytokinins is in treatment T3, which raised value of potassium concentration in leaves, this influenced optimal development, strengthening against environmental stress and therefore quality. For this reason, research was carried out on the comparative study of cytokinin doses in the quality of caigua in Peru; the objective was to determine the appropriate dose to obtain higher quality fruit. Likewise, it was underlined that the objective was to employ an ecological alternative of plant origin such as the usage of phytohormone that stimulates the growth of the plant and consequently the quality of the fruit. The obtained the results were served as a recommendation for farmers in the area.


Asunto(s)
Citocininas , Reguladores del Crecimiento de las Plantas , Citocininas/farmacología , Perú , Reguladores del Crecimiento de las Plantas/farmacología , Hojas de la Planta/fisiología , Estrés Fisiológico
9.
Nat Commun ; 14(1): 7106, 2023 11 04.
Artículo en Inglés | MEDLINE | ID: mdl-37925502

RESUMEN

The size of plant lateral organs is determined by well-coordinated cell proliferation and cell expansion. Here, we report that miR159, an evolutionarily conserved microRNA, plays an essential role in regulating cell division in rose (Rosa hybrida) petals by modulating cytokinin catabolism. We uncover that Cytokinin Oxidase/Dehydrogenase6 (CKX6) is a target of miR159 in petals. Knocking down miR159 levels results in the accumulation of CKX6 transcripts and earlier cytokinin clearance, leading to a shortened cell division period and smaller petals. Conversely, knocking down CKX6 causes cytokinin accumulation and a prolonged developmental cell division period, mimicking the effects of exogenous cytokinin application. MYB73, a R2R3-type MYB transcription repressor, recruits a co-repressor (TOPLESS) and a histone deacetylase (HDA19) to form a suppression complex, which regulates MIR159 expression by modulating histone H3 lysine 9 acetylation levels at the MIR159 promoter. Our work sheds light on mechanisms for ensuring the correct timing of the exit from the cell division phase and thus organ size regulation by controlling cytokinin catabolism.


Asunto(s)
Rosa , Rosa/genética , Proteínas de Plantas/genética , Factores de Transcripción/metabolismo , Regiones Promotoras Genéticas , Citocininas/farmacología , Regulación de la Expresión Génica de las Plantas , Flores/fisiología
10.
Plant Cell Rep ; 42(12): 1927-1936, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37803214

RESUMEN

KEY MESSAGE: Increase of ENHANCER OF SHOOT REGENERATION 2 expression was consistent to treatment with kinetin, TIS108, and KK094 in adventitious shoot formation of ipecac. Unlike many plant species, ipecac (Carapichea ipecacuanha (Brot.) L. Andersson) can form adventitious shoots in tissue culture without cytokinin (CK) treatment. Strigolactone (SL) biosynthesis and signaling inhibitors stimulate adventitious shoot formation in ipecac, suggesting their potential use as novel growth regulators in plant tissue culture, but the molecular mechanism of their action is unclear. In this study, we compared the effects of SL-related inhibitors (TIS108 and KK094) and CKs (2iP, tZ, and kinetin) on adventitious shoot formation in ipecac. Exogenously applied SL-related inhibitors and CKs stimulated adventitious shoot formation. Combinations of SL-related inhibitors and kinetin also promoted adventitious shoot formation, but without additive effects. We also analyzed the expression of CK biosynthesis genes in ipecac. TIS108 increased the expression of the ipecac homolog of ISOPENTENYL TRANSFERASE 3 (CiIPT3) but decreased that of LONELY GUY 7 homolog (CiLOG7), presumably resulting in no change in 2iP-type CK levels. KK094 and kinetin increased CiLOG7 expression, elevating 2iP-type CK levels. Among pluripotency- and meristem-related genes, TIS108, KK094, and kinetin consistently increased the expression of ENHANCER OF SHOOT REGENERATION 2 homolog (CiESR2), which has a key role in shoot regeneration, in the internodal segment region that formed adventitious shoots. We propose that CiESR2 might be a key stimulator of adventitious shoot formation in ipecac.


Asunto(s)
Citocininas , Ipeca , Cinetina/farmacología , Ipeca/farmacología , Brotes de la Planta , Citocininas/farmacología , Reguladores del Crecimiento de las Plantas/farmacología
11.
J Exp Bot ; 74(21): 6541-6550, 2023 11 21.
Artículo en Inglés | MEDLINE | ID: mdl-37498739

RESUMEN

Crosstalk between auxin and cytokinin contributes to widespread developmental processes, including root and shoot meristem maintenance, phyllotaxy, and vascular patterning. However, our understanding of crosstalk between these hormones is limited primarily to angiosperms. The moss Physcomitrium patens (formerly Physcomitrella patens) is a powerful system for studying plant hormone function. Auxin and cytokinin play similar roles in regulating moss gametophore (shoot) architecture, to those in flowering plant shoots. However, auxin-cytokinin crosstalk is poorly understood in moss. Here we find that the ratio of auxin to cytokinin is an important determinant of development in P. patens, especially during leaf development and branch stem cell initiation. Addition of high levels of auxin to P. patens gametophores blocks leaf outgrowth. However, simultaneous addition of high levels of both auxin and cytokinin partially restores leaf outgrowth, suggesting that the ratio of these hormones is the predominant factor. Likewise, during branch initiation and outgrowth, chemical inhibition of auxin synthesis phenocopies cytokinin application. Finally, cytokinin-insensitive mutants resemble plants with altered auxin signaling and are hypersensitive to auxin. In summary, our results suggest that the ratio between auxin and cytokinin signaling is the basis for developmental decisions in the moss gametophore.


Asunto(s)
Briófitas , Bryopsida , Citocininas/farmacología , Ácidos Indolacéticos/farmacología , Bryopsida/genética , Meristema , Hojas de la Planta , Hormonas
12.
Biomolecules ; 13(3)2023 03 13.
Artículo en Inglés | MEDLINE | ID: mdl-36979458

RESUMEN

Delayed or incomplete recovery of gas exchange after water stress relief limits assimilation in the post-drought period and can thus negatively affect the processes of post-drought recovery. Abscisic acid (ABA) accumulation and antagonistic action between ABA and cytokinins (CKs) play an important role in regulation of stomatal conductance under water deficit. Specifically, in pine species, sustained ABA accumulation is thought to be the main cause of delayed post-drought gas exchange recovery, although the role of CKs is not yet known. Therefore, we aimed to study the effects of ABA and CKs on recovery of stomatal conductance in greenhouse-grown 3-year-old Scots pine saplings recovering from water stress. We analysed both changes in endogenous ABA and CK contents and the effects of treatment with exogenous CK on stomatal conductance. Drought stress suppressed stomatal conductance, and post-drought stomatal conductance remained suppressed for 2 weeks after plant rewatering. ABA accumulated during water stress, but ABA levels decreased rapidly after rewatering. Additionally, trans-zeatin/ABA and isopentenyladenine/ABA ratios, which were decreased in water-stressed plants, recovered rapidly in rewatered plants. Spraying plants with 6-benzylaminopurine (0.1-100 µM) did not influence recovery of either stomatal conductance or needle water status. It can be concluded that the delayed recovery of stomatal conductance in Scots pine needles was not due to sustained ABA accumulation or a sustained decrease in the CK/ABA ratio, and CK supplementation was unable to overcome this delayed recovery.


Asunto(s)
Ácido Abscísico , Citocininas , Ácido Abscísico/farmacología , Citocininas/farmacología , Resistencia a la Sequía , Deshidratación , Estomas de Plantas , Plantas
13.
Plant Physiol ; 191(4): 2447-2460, 2023 04 03.
Artículo en Inglés | MEDLINE | ID: mdl-36722159

RESUMEN

Rhizobia-legume interactions recruit cytokinin for the induction of nodule primordia in the cortex. Cytokinin signaling regulates auxin transport and biosynthesis, causing local auxin accumulation, which triggers cortical cell division. Since sugar signaling can trigger auxin responses, we explored whether sugar treatments could rescue symbiosis in the Medicago truncatula cytokinin response 1 (cre1) mutant. Herein, we demonstrate that sucrose and its nonmetabolizable isomer turanose can trigger auxin response and recover functional symbiosis in cre1, indicating sucrose signaling to be necessary for the restoration of symbiosis. In both M. truncatula A17 (wild type) and cre1, sucrose signaling significantly upregulated IAA-Ala Resistant 3 (IAR33), encoding an auxin conjugate hydrolase, in rhizobia-infected as well as in uninfected roots. Knockdown of IAR33 (IAR33-KD) significantly reduced nodulation in A17, highlighting the importance of deconjugation-mediated auxin accumulation during nodule inception. In cre1, IAR33-KD restricted the sucrose-mediated restoration of functional symbiosis, suggesting that deconjugation-mediated auxin accumulation plays a key role in the absence of CRE1-mediated auxin biosynthesis and transport control. Overexpression of IAR33 also restored functional symbiosis in cre1, further suggesting that IAR33 mediates auxin accumulation in response to sucrose signaling. Since all the observed sucrose-mediated responses were common to A17 and cre1, deconjugation-mediated auxin response appeared to be independent of CRE1, which normally governs local auxin accumulation in the presence of rhizobia. We propose that sucrose-dependent restoration of symbiosis in cre1 occurs by the activation of IAR33-mediated auxin deconjugation.


Asunto(s)
Citocininas , Medicago truncatula , Citocininas/farmacología , Citocininas/metabolismo , Ácidos Indolacéticos/metabolismo , Simbiosis/genética , Sacarosa/metabolismo , Raíces de Plantas/metabolismo , Medicago truncatula/genética , Medicago truncatula/metabolismo , Percepción , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo
14.
Int J Mol Sci ; 24(3)2023 Feb 03.
Artículo en Inglés | MEDLINE | ID: mdl-36769369

RESUMEN

Knotted1-like homeobox (KNOX) transcription factors are involved in plant development, playing complex roles in aerial organs. As Prunus species include important fruit tree crops of Italy, an exhaustive investigation of KNOX genes was performed using genomic and RNA-seq meta-analyses. Micropropagation is an essential technology for rootstock multiplication; hence, we investigated KNOX transcriptional behavior upon increasing 6-benzylaminopurine (BA) doses and the effects on GF677 propagules. Moreover, gene function in Prunus spp. was assessed by Gisela 6 rootstock transformation using fluorescence and peach KNOX transgenes. Based on ten Prunus spp., KNOX proteins fit into I-II-M classes named after Arabidopsis. Gene number, class member distribution, and chromosome positions were maintained, and exceptions supported the diversification of Prunus from Cerasus subgenera, and that of Armeniaca from the other sections within Prunus. Cytokinin (CK) cis-elements occurred in peach and almond KNOX promoters, suggesting a BA regulatory role in GF677 shoot multiplication as confirmed by KNOX expression variation dependent on dose, time, and interaction. The tripled BA concentration exacerbated stress, altered CK perception genes, and modified KNOX transcriptions, which are proposed to concur in in vitro anomalies. Finally, Gisela 6 transformation efficiency varied (2.6-0.6%) with the genetic construct, with 35S:GFP being more stable than 35S:KNOPE1 lines, which showed leaf modification typical of KNOX overexpression.


Asunto(s)
Arabidopsis , Prunus persica , Prunus , Citocininas/farmacología , Citocininas/metabolismo , Prunus/metabolismo , Proteínas de Homeodominio/genética , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Genes Homeobox , Arabidopsis/genética , Prunus persica/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Regulación de la Expresión Génica de las Plantas
15.
Int J Mol Sci ; 24(1)2023 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-36614184

RESUMEN

Fine-tuned interactions between melatonin (MT) and hormones affected by environmental inputs are crucial for plant growth. Under high light (HL) conditions, melatonin reduced photodamage in Arabidopsis thaliana and contributed to the restoration of the expression of the cytokinin (CK) synthesis genes IPT3, IPT5 and LOG7 and genes for CK signal transduction AHK2,3 and ARR 1, 4, 5 and 12 which were downregulated by stress. However, CK signaling mutants displayed no significant changes in the expression of CK genes following HL + MT treatment, implying that a fully functional cytokinin signaling pathway is a prerequisite for MT-CK interactions. In turn, cytokinin treatment increased the expression of the key melatonin synthesis gene ASMT under both moderate and HL in wild-type plants. This upregulation was further accentuated in the ipt3,5,7 mutant which is highly sensitive to CK. In this mutant, in addition to ASMT, the melatonin synthesis genes SNAT and COMT, as well as the putative signaling genes CAND2 and GPA1, displayed elevated transcript levels. The results of the study suggest that melatonin acts synergistically with CK to cope with HL stress through melatonin-associated activation or repression of the respective hormonal genes.


Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Melatonina , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Citocininas/farmacología , Citocininas/metabolismo , Regulación de la Expresión Génica de las Plantas , Subunidades alfa de la Proteína de Unión al GTP/metabolismo , Melatonina/farmacología , Melatonina/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Transducción de Señal/genética , Estrés Fisiológico
16.
Plant Physiol ; 192(2): 1420-1434, 2023 May 31.
Artículo en Inglés | MEDLINE | ID: mdl-36690819

RESUMEN

The inhibition of shoot branching by the growing shoot tip of plants, termed apical dominance, was originally thought to be mediated by auxin. Recently, the importance of the shoot tip sink strength during apical dominance has re-emerged with recent studies highlighting roles for sugars in promoting branching. This raises many unanswered questions on the relative roles of auxin and sugars in apical dominance. Here we show that auxin depletion after decapitation is not always the initial trigger of rapid cytokinin (CK) increases in buds that are instead correlated with enhanced sugars. Auxin may also act through strigolactones (SLs) which have been shown to suppress branching after decapitation, but here we show that SLs do not have a significant effect on initial bud outgrowth after decapitation. We report here that when sucrose or CK is abundant, SLs are less inhibitory during the bud release stage compared to during later stages and that SL treatment rapidly inhibits CK accumulation in pea (Pisum sativum) axillary buds of intact plants. After initial bud release, we find an important role of gibberellin (GA) in promoting sustained bud growth downstream of auxin. We are, therefore, able to suggest a model of apical dominance that integrates auxin, sucrose, SLs, CKs, and GAs and describes differences in signalling across stages of bud release to sustained growth.


Asunto(s)
Decapitación , Reguladores del Crecimiento de las Plantas , Reguladores del Crecimiento de las Plantas/farmacología , Ácidos Indolacéticos/farmacología , Citocininas/farmacología , Sacarosa/farmacología , Azúcares/farmacología , Pisum sativum , Brotes de la Planta , Regulación de la Expresión Génica de las Plantas
17.
Phytochemistry ; 205: 113481, 2023 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-36283448

RESUMEN

Isoprenoid cytokinins are a class of naturally occurring plant signaling molecules. A series of prepared compounds derived from isoprenoid cytokinins (isopentenyladenine, trans-zeatin and cis-zeatin) with attached 2'-deoxy-d-ribose or 2',3'-dideoxy-d-ribose at the N9 position of the purine were prepared and their biological activities were examined. Different synthetic approaches were employed. The final compounds were characterized with variety of physicochemical methods (TLC, HPLC-MS, and NMR) and their cytokinin activity was determined in classical bioassays such as Amaranthus, tobacco callus, detached wheat leaf senescence and Arabidopsis thaliana root elongation inhibition assay. In addition, compounds were screened for activation of the cytokinin signaling pathway (bacterial receptor, competitive ligand binding and ARR5::GUS assay) to provide a detailed assessment of CK structure-activity relationship. The prepared compounds were found to be non-toxic to human cells and the majority of assays exhibited the highest activity of free bases while 2',3'-dideoxyribosides had very weak or no activity. In contrast to the free bases, all 2'-deoxyriboside derivatives were not toxic to tobacco callus even at the highest tested concentration (10-4 moL/l) and compound 1 (iPdR) induced betacyanin synthesis at higher concentration even stronger than iP free base in the Amaranthus bioassay. The general cytokinin activity pattern base > riboside >2'-deoxyriboside > 2',3'-dideoxyriboside was distinguished.


Asunto(s)
Citocininas , Terpenos , Humanos , Citocininas/farmacología , Ribosa
18.
Dokl Biochem Biophys ; 513(Suppl 1): S23-S25, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-38189887

RESUMEN

For the first time, N6-(5-phenylpentan-1-yl)adenine, a synthetic adenine derivative with a receptor-specific anticytokinin effect, was obtained. This compound exhibits a pronounced anticytokinin effect, reducing cytokinin-induced expression of the GUS reporter gene when interacting with the cytokinin receptor CRE1/AHK4 of the model plant Arabidopsis thaliana. This effect manifests itself much weaker with the related AHK2 receptor and is not observed at all with the AHK3 receptor. We showed that N6-(5-phenylpentan-1-yl)adenine does not bind to the ligand-binding sites of the Arabidopsis cytokinin receptors, which does not allow it to be classified as a true cytokinin antagonist. Despite the currently unknown mechanism of action, this compound may find its use as a component of plant growth regulators. Like true anticytokinins, it enhances root growth of Arabidopsis seedlings, apparently suppressing the action of endogenous cytokinins on the "root" receptor CRE1/AHK4.


Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Citocininas/farmacología , Citocininas/metabolismo , Adenina/farmacología , Adenina/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Proteínas Quinasas/genética , Proteínas Quinasas/metabolismo , Histidina Quinasa/metabolismo , Receptores de Superficie Celular/genética
19.
J Agric Food Chem ; 70(51): 16229-16240, 2022 Dec 28.
Artículo en Inglés | MEDLINE | ID: mdl-36515163

RESUMEN

Food is a fundamental human right, and global food security is threatened by crop production. Plant growth regulators (PGRs) play an essential role in improving crop yield and quality, and this study reports on a novel PGR, termed guvermectin (GV), isolated from plant growth-promoting rhizobacteria, which can promote root and coleoptile growth, tillering, and early maturing in rice. GV is a nucleoside analogue like cytokinin (CK), but it was found that GV significantly promoted root and hypocotyl growth, which is different from the function of CK in Arabidopsis. The Arabidopsis CK receptor triple mutant ahk2-2 ahk3-3 cre1-12 still showed a GV response. Moreover, GV led different growth-promoting traits from auxin, gibberellin (GA), and brassinosteroid (BR) in Arabidopsis and rice. The results from a four-year field trial involving 28 rice varieties showed that seed-soaking treatment with GV increased the yields by 6.2 to 19.6%, outperforming the 4.0 to 10.8% for CK, 1.6 to 16.9% for BR, and 2.2 to 7.1% for GA-auxin-BR mixture. Transcriptome analysis demonstrated that GV induced different transcriptome patterns from CK, auxin, BR, and GA, and SAUR genes may regulate GV-mediated plant growth and development. This study suggests that GV represents a novel PGR with a unique signal perception and transduction pathway in plants.


Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Oryza , Humanos , Reguladores del Crecimiento de las Plantas/farmacología , Reguladores del Crecimiento de las Plantas/metabolismo , Arabidopsis/metabolismo , Oryza/metabolismo , Biomasa , Citocininas/farmacología , Proteínas de Arabidopsis/metabolismo , Ácidos Indolacéticos/metabolismo , Brasinoesteroides/metabolismo , Grano Comestible/metabolismo , Regulación de la Expresión Génica de las Plantas
20.
PeerJ ; 10: e14315, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36340204

RESUMEN

The plant hormones ethylene and cytokinin influence many processes; sometimes they act cooperatively, other times antagonistically. To study their antagonistic interaction, we used the cotyledons of etiolated, intact seedlings of Arabidopsis thaliana. We focused on cell division and expansion, because both processes are quantified readily in paradermal sections. Here, we show that exogenous cytokinins modestly stimulate cell division and expansion in the cotyledon, with a phenyl-urea class compound exerting a larger effect than benzyl-adenine. Similarly, both processes were stimulated modestly when ethylene response was inhibited, either chemically with silver nitrate or genetically with the eti5 ethylene-insensitive mutant. However, combining cytokinin treatment with ethylene insensitivity was synergistic, strongly stimulating both cell division and expansion. Evidently, ethylene represses the growth promoting influence of cytokinin, whether endogenous or applied. We suggest that the intact etiolated cotyledon offers a useful system to characterize how ethylene antagonizes cytokinin responsiveness.


Asunto(s)
Arabidopsis , Citocininas , Citocininas/farmacología , Arabidopsis/genética , Cotiledón , Plantones/genética , Etilenos/farmacología , División Celular
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