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KEY MESSAGE: The hybrid rice variety (Hanyou73) exhibits the maternal-like (HH7A) gene expression in roots and parental-like (HH3) gene expression in leaves to obtain both advantages of drought avoidance and drought tolerance from its two parents. BACKGROUND: Rice is one of the most important crops in the world. Rice production consumes lots of water and significantly suffers from the water deficiency and drought stress. The water-saving and drought-resistance rice (WDR) confers good drought resistance and performs well in the water-saving cultivation. MAIN FINDINGS: A hybrid WDR variety Hanyou73 (HY73) exhibited superior drought resistance compared with its parents Hanhui3 (HH3) and Huhan7A (HH7A). Studies on drought resistance related traits revealed that HY73 performed like HH3 and HH7A on drought tolerance and drought avoidance, respectively. Transcriptomes were analyzed for samples with various phytohormone treatments and abiotic stresses, in which HY73 was closer to HH3 in leaf samples while HH7A in root samples. HY73 and its parents differed largely in DEGs and GO analysis for DEGs suggested the different pathways of drought response in HH3 and HH7A. Parent-like expression analysis revealed that the higher-parent-like expression pattern was prevailing in HY73. In addition, patterns of the parent-like expression significantly transformed between abiotic-stressed/phytohormone-treated and control samples, which might help HY73 to adapt to different environments. WGCNA analysis for those parent-like expression genes revealed some drought resistant genes that should contribute to the superior drought resistance of HY73. Genetic variation on the promotor sequence was confirmed as the reason for the flexible parent-like gene expression in HY73. CONCLUSION: Our study uncovered the important roles of complementation of beneficial traits from parents and flexible gene expressions in drought resistance of HY73, which could facilitate the development of new WDR varieties.
Assuntos
Secas , Regulação da Expressão Gênica de Plantas , Oryza , Oryza/genética , Oryza/fisiologia , Estresse Fisiológico/genética , Água , Raízes de Plantas/genética , Raízes de Plantas/fisiologia , Folhas de Planta/genética , Folhas de Planta/fisiologia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Fenótipo , Genes de Plantas , Resistência à SecaRESUMO
Betula utilis exhibits intriguing characteristics and interactions with its environment and has specific adaptations that enable it to thrive in various water conditions. Drought has a prominent role in influencing the growth and development of vegetation, while temperature serves as a crucial determinant of species distribution in high-altitude environments. The investigation was centered on the eco-physiological dimension of B. utilis in areas near the treeline. Across different seasons, sites, and years, the most negative pre-dawn twig water potentials (ΨPD) and mid-day twig water potentials (ΨMD) were - 0.81 and - 1.24 MPa, respectively. The highest seasonal change (ΔΨ) in twig water potential (Ψtwig) was in the post-monsoon season. Osmotic potential at full turgor (Ψπ100) declined by - 0.66 MPa and osmotic potential at zero turgor (Ψπ0) declined by - 1.07 MPa. The highest leaf conductance (gw) of 380.26 mmol m-2 s-1 was measured in the afternoon. During the initiation of flowering, ΨPD of the twig was - 0.72 MPa and gradually rose to - 0.17 MPa by the end of the flowering period. This study provides key insight into the Ψ dynamics, leaf conductance, and phenology of B. utilis, highlighting its adaptation to changing environmental conditions and the need for effective management strategies to ensure the resilience and conservation of this Critically Endangered species.
Assuntos
Betula , Estações do Ano , Água , Água/metabolismo , Betula/crescimento & desenvolvimento , Folhas de Planta/fisiologia , Ecossistema , Altitude , Temperatura , SecasRESUMO
BACKGROUND: Global warming has greatly increased the impact of high temperatures on crops, resulting in reduced yields and increased mortality. This phenomenon is of significant importance to the rose flower industry because high-temperature stress leads to bud dormancy or even death, reducing ornamental value and incurring economic losses. Understanding the molecular mechanisms underlying the response and resistance of roses to high-temperature stress can serve as an important reference for cultivating high-temperature-stress-resistant roses. RESULTS: To evaluate the impact of high temperatures on rose plants, we measured physiological indices in rose leaves following heat stress. Protein and chlorophyll contents were significantly decreased, whereas proline and malondialdehyde (MDA) contents, and peroxidase (POD) activity were increased. Subsequently, transcriptomics and metabolomics analyses identified 4,652 common differentially expressed genes (DEGs) and 57 common differentially abundant metabolites (DAMs) in rose plants from four groups. Enrichment analysis showed that DEGs and DAMs were primarily involved in the mitogen-activated protein kinases (MAPK) signaling pathway, plant hormone signal transduction, alpha-linolenic acid metabolism, phenylpropanoid biosynthesis, and flavonoid biosynthesis. The combined analysis of the DEGs and DAMs revealed that flavonoid biosynthesis pathway-related genes, such as chalcone isomerase (CHI), shikimate O-hydroxycinnamoyl transferase (HCT), flavonol synthase (FLS), and bifunctional dihydroflavonol 4-reductase/flavanone 4-reductase (DFR), were downregulated after heat stress. Moreover, in the MAPK signaling pathway, the expression of genes related to jasmonic acid exhibited a decrease, but ethylene receptor (ETR/ERS), P-type Cu + transporter (RAN1), ethylene-insensitive protein 2/3 (EIN2), ethylene-responsive transcription factor 1 (ERF1), and basic endochitinase B (ChiB), which are associated with the ethylene pathway, were mostly upregulated. Furthermore, heterologous overexpression of the heat stress-responsive gene RcHSP70 increased resistance to heat stress in Arabidopsis thaliana. CONCLUSION: The results of this study indicated that the flavonoid biosynthesis pathway, MAPK signaling pathway, and plant hormones may be involved in high-temperature resistance in roses. Constitutive expression of RcHSP70 may contribute to increasing high-temperature tolerance. This study provides new insights into the genes and metabolites induced in roses in response to high temperature, and the results provide a reference for analyzing the molecular mechanisms underlying resistance to heat stress in roses.
Assuntos
Resposta ao Choque Térmico , Metabolômica , Rosa , Rosa/genética , Rosa/metabolismo , Rosa/fisiologia , Resposta ao Choque Térmico/genética , Perfilação da Expressão Gênica , Transcriptoma , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Folhas de Planta/metabolismo , Folhas de Planta/genética , Folhas de Planta/fisiologiaRESUMO
BACKGROUND: Sustainable crop production along with best nutrient use efficiency is the key indicator of smart agriculture. Foliar application of plant nutrients can complement soil fertilization with improved nutrient uptake, translocation and utilization. Recent developments in slow releasing, nano-fertilizers in agriculture, begins a new era for sustainable use and management of natural resources. This study aims to explore the effectiveness of nano-nitrogen usage on plant growth, yield attributes and sustaining rice production while optimizing fertilizer N application through conventional (prilled urea) and nano-N source under salt stress conditions. RESULTS: The strategic substitutions of traditional urea by nano-nitrogen was distributed from partial to complete with 33, 50, 66 and 100% applications. Further, the strategic substitutions were compared in saline (ECe â¼ 6.0 dSm- 1) and sodic stress (pH â¼ 9.1) conditions along with normal soils to dissect the beneficial response of nano-N in two rice varieties (CSR 30 and PB 1121). Salt stress affected the plant performance by decreasing leaf relative water content upto 10%, total chlorophyll content by 1.3-1.5%, leaf area upto 29.9%, gas exchange attributes by 10-39%, with concomitant yield reductions upto â¼ 4%. Collateral improvement in leaf greenness (SPAD index) crop growth rate and net assimilation rate was observed with foliar application of Nano-N. 0.2-1.64% enhancement in growth traits, 0.93-1.85% in physiological traits, and comparable yield gains with 100% recommended dose of prilled were comparative with nano-substitutions. Salt tolerant rice variety, CSR-30 performed better than PB 1121 with better expression of morphological, physiological and yield traits under stress conditions and nitrogen substitutions. CONCLUSIONS: Overall, our experimental findings revealed agricultural use of nano-N in improving the plant physiological efficiency and optimizing rice yields with partial N substitution through nano fertilizers under salt stress conditions. These studies are further open for futuristic aspects of long term effects of nano-fertilizers on soil nutrient depletion in correlation to yield enhancement in salt affected soils.
Assuntos
Fertilizantes , Nitrogênio , Oryza , Estresse Salino , Oryza/genética , Oryza/crescimento & desenvolvimento , Oryza/fisiologia , Oryza/efeitos dos fármacos , Oryza/metabolismo , Nitrogênio/metabolismo , Solo/química , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/fisiologia , Folhas de Planta/metabolismoRESUMO
KEY MESSAGE: The barley mutant xan-h.chli-1 shows phenotypic features, such as reduced leaf chlorophyll content and daily transpiration rate, typical of wild barley accessions and landraces adapted to arid climatic conditions. The pale green trait, i.e. reduced chlorophyll content, has been shown to increase the efficiency of photosynthesis and biomass accumulation when photosynthetic microorganisms and tobacco plants are cultivated at high densities. Here, we assess the effects of reducing leaf chlorophyll content in barley by altering the chlorophyll biosynthesis pathway (CBP). To this end, we have isolated and characterised the pale green barley mutant xan-h.chli-1, which carries a missense mutation in the Xan-h gene for subunit I of Mg-chelatase (HvCHLI), the first enzyme in the CBP. Intriguingly, xan-h.chli-1 is the only known viable homozygous mutant at the Xan-h locus in barley. The Arg298Lys amino-acid substitution in the ATP-binding cleft causes a slight decrease in HvCHLI protein abundance and a marked reduction in Mg-chelatase activity. Under controlled growth conditions, mutant plants display reduced accumulation of antenna and photosystem core subunits, together with reduced photosystem II yield relative to wild-type under moderate illumination, and consistently higher than wild-type levels at high light intensities. Moreover, the reduced content of leaf chlorophyll is associated with a stable reduction in daily transpiration rate, and slight decreases in total biomass accumulation and water-use efficiency, reminiscent of phenotypic features of wild barley accessions and landraces that thrive under arid climatic conditions.
Assuntos
Clorofila , Hordeum , Liases , Mutação de Sentido Incorreto , Folhas de Planta , Proteínas de Plantas , Transpiração Vegetal , Hordeum/genética , Hordeum/fisiologia , Hordeum/enzimologia , Clorofila/metabolismo , Transpiração Vegetal/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Folhas de Planta/genética , Folhas de Planta/fisiologia , Liases/genética , Liases/metabolismo , Fotossíntese/genética , Fenótipo , Complexo de Proteína do Fotossistema II/metabolismo , Complexo de Proteína do Fotossistema II/genéticaRESUMO
Water-saving and drought-resistant rice (WDR) coupled with alternate wetting and drying irrigation (AWDI) possesses a high photosynthetic potential due to higher mesophyll conductance (gm) under drought conditions. However, the physiological and structural contributions to the gm of leaves and their mechanisms in WDR under AWDI are still unclear. In this study, WDR (Hanyou 73) and drought-sensitive rice (Huiliangyou 898) were selected as materials. Three irrigation patterns were established from transplanting to the heading stage, including conventional flooding irrigation (W1), moderate AWDI (W2), and severe AWDI (W3). A severe drought with a soil water potential of -50 kPa was applied for a week at the heading stage across all treatments and cultivars. The results revealed that severe drought reduced gas exchange parameters and gm but enhanced antioxidant enzyme activities and malondialdehyde content in the three treatments and both cultivars. The maximal photosynthetic rate (Amax) of HY73 in the W2 treatment was greater than that in the other combinations of cultivars and irrigation patterns. The contribution of leaf structure (54%) to gm (gm-S, structural gm) was higher than that of leaf physiology (46%) to gm (gm-P, physiological gm) in the W2 treatment of Hanyou 73. Additionally, gm-S was significantly and linearly positively correlated with gm under severe drought. Moreover, both the initial and apparent quantum efficiencies were significantly and positively with gm in rice plants (p < 0.05). These results suggest that the improvements in photosynthesis and yield in the WDR combined with moderate AWDI can mainly be attributed to the enhancement of gm-S under severe drought conditions. Quantum efficiency may be a potential factor in regulating photosynthesis by cooperating with the gm of rice plants under severe drought conditions.
Assuntos
Irrigação Agrícola , Secas , Células do Mesofilo , Oryza , Fotossíntese , Folhas de Planta , Água , Oryza/fisiologia , Água/metabolismo , Irrigação Agrícola/métodos , Fotossíntese/fisiologia , Células do Mesofilo/fisiologia , Folhas de Planta/fisiologia , Transpiração Vegetal/fisiologia , Dessecação/métodosRESUMO
The main aim of this work was to better understand how the low temperature signal from the leaves may affect the stress responses in the roots, and how the light conditions modify certain stress acclimation processes in rice plants. Rice plants grown at 27°C were exposed to low temperatures (12°C) with different light intensities, and in the case of some groups of plants, only the leaves received the cold, while the roots remained at control temperature. RNA sequencing focusing on the roots of plants grown under normal growth light conditions found 525 differentially expressed genes in different comparisons. Exposure to low temperature led to more down-regulated than up-regulated genes. Comparison between roots of the leaf-stressed plants and whole cold-treated or control plants revealed that nitrogen metabolism and nitric oxide-related signalling, as well as the phenylpropanoid-related processes, were specifically affected. Real-time PCR results focusing on the COLD1 and polyamine oxidase genes, as well as metabolomics targeting hormonal changes and phenolic compounds also showed that not only cold exposure of the leaves, either alone or together with the roots, but also the light conditions may influence certain stress responses in the roots of rice plants.
Assuntos
Regulação da Expressão Gênica de Plantas , Luz , Oryza , Raízes de Plantas , Brotos de Planta , Transdução de Sinais , Estresse Fisiológico , Oryza/genética , Oryza/efeitos da radiação , Oryza/fisiologia , Oryza/metabolismo , Raízes de Plantas/genética , Raízes de Plantas/efeitos da radiação , Raízes de Plantas/fisiologia , Raízes de Plantas/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos da radiação , Transdução de Sinais/efeitos da radiação , Estresse Fisiológico/genética , Brotos de Planta/efeitos da radiação , Brotos de Planta/genética , Brotos de Planta/fisiologia , Brotos de Planta/metabolismo , Folhas de Planta/efeitos da radiação , Folhas de Planta/genética , Folhas de Planta/metabolismo , Folhas de Planta/fisiologia , Temperatura Baixa , Temperatura , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismoRESUMO
BACKGROUND: Developmental leaf senescence (DLS) is an irreversible process followed by cell death. Dark-induced leaf senescence (DILS) is a reversible process that allows adaptations to changing environmental conditions. As a result of exposure to adverse environmental changes, plants have developed mechanisms that enable them to survive. One of these is the redirection of metabolism into the senescence pathway. The plant seeks to optimise resource allocation. Our research aims to demonstrate how epigenetic machinery regulates leaf senescence, including its irreversibility. RESULTS: In silico analyses allowed the complex identification and characterisation of 117 genes involved in epigenetic processes in barley. These genes include those responsible for DNA methylation, post-translational histone modifications, and ATP-dependent chromatin remodelling complexes. We then performed RNAseq analysis after DILS and DLS to evaluate their expression in senescence-dependent leaf metabolism. Principal component analysis revealed that evaluated gene expression in developmental senescence was similar to controls, while induced senescence displayed a distinct profile. Western blot experiments revealed that senescence engages senescence-specific histone modification. During DILS and DLS, the methylation of histone proteins H3K4me3 and H3K9me2 increased. H3K9ac acetylation levels significantly decreased during DILS and remained unchanged during DLS. CONCLUSIONS: The study identified different epigenetic regulations of senescence types in barley leaves. These findings are valuable for exploring epigenetic regulation of senescence-related molecular mechanisms, particularly in response to premature, induced leaf senescence. Based on the results, we suggest the presence of an epigenetically regulated molecular switch between cell survival and cell death in DILS, highlighting an epigenetically driven cell survival metabolic response.
Assuntos
Epigênese Genética , Hordeum , Folhas de Planta , Senescência Vegetal , Hordeum/genética , Hordeum/fisiologia , Folhas de Planta/genética , Folhas de Planta/fisiologia , Senescência Vegetal/genética , Regulação da Expressão Gênica de Plantas , Metilação de DNA , Histonas/metabolismoRESUMO
To investigate the response of blueberry photosynthetic physiology to different light intensities during different stages of fruit development. In this study, four light intensity treatments (25%, 50%, 75% and 100% of full light) were set up to study the change rule of photosynthetic pigment content and photosynthetic characteristics of 'O'Neal' southern highbush blueberry leaves during the white fruiting stage (S1), purple fruiting stage (S2) and blue fruiting stage (S3) under different light intensity environments, and to explore the light demand and light adaptability of blueberry during different developmental stages of the fruit. The results showed that the chlorophyll and carotenoid contents of blueberry leaves showed an increasing trend with decreasing light intensity at all three stages of fruit development. The total chlorophyll content of blueberry leaves at 25% light intensity increased by 76.4% compared with CK during the blue fruiting stage; the maximum net photosynthetic rate (Pmax), light compensation point (LCP), light saturation point (LSP), rate of dark respirations (Rd), inter-cellular CO2 concentration (Ci), stomatal conductance (Gs), transpiration rate (Tr), net photosynthesis rate (Pn), and chlorophyll a/b showed a decreasing trend with decreasing light intensity. The Pn of blueberry leaves was highest under full light conditions at all three stages, and the Pn at 25% light intensity decreased by 68.5% compared with CK during the white fruiting stage Reflecting the fact that blueberries can adapt to low-light environments through increases in chlorophyll and carotenoids, but reduced light intensity significantly inhibited their photosynthesis. The photosynthetic physiology of blueberry showed a consistent pattern at all three stages, but there were some differences in the changes of photosynthetic parameters at different stages. The results of the study can provide theoretical references for the selection of sites and density regulation in blueberry production.
Assuntos
Mirtilos Azuis (Planta) , Clorofila , Frutas , Luz , Fotossíntese , Folhas de Planta , Fotossíntese/fisiologia , Mirtilos Azuis (Planta)/crescimento & desenvolvimento , Mirtilos Azuis (Planta)/fisiologia , Frutas/crescimento & desenvolvimento , Frutas/efeitos da radiação , Frutas/fisiologia , Clorofila/metabolismo , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/efeitos da radiação , Folhas de Planta/fisiologia , Carotenoides/metabolismoRESUMO
MAIN CONCLUSION: The high intrinsic water-use efficiency of Erianthus may be due to the low abaxial stomatal density and the accumulation of leaf metabolites such as betaine and gamma-aminobutyric acid. Sugarcane is an important crop that is widely cultivated in tropical and subtropical regions of the world. Because drought is among the main impediments limiting sugarcane production in these regions, breeding of drought-tolerant sugarcane varieties is important for sustainable production. Erianthus arundinaceus, a species closely related to sugarcane, exhibits high intrinsic water-use efficiency (iWUE), the underlying mechanisms for which remain unknown. To improve the genetic base for conferring drought tolerance in sugarcane, in the present study, we performed a comprehensive comparative analysis of leaf gas exchange and metabolites in different organs of sugarcane and Erianthus under wet and dry soil-moisture conditions. Erianthus exhibited lower stomatal conductance under both conditions, which resulted in a higher iWUE than in sugarcane. Organ-specific metabolites showed gradations between continuous parts and organs, suggesting linkages between them. Cluster analysis of organ-specific metabolites revealed the effects of the species and treatments in the leaves. Principal component analysis of leaf metabolites confirmed a rough ordering of the factors affecting their accumulations. Compared to sugarcane leaf, Erianthus leaf accumulated more raffinose, betaine, glutamine, gamma-aminobutyric acid, and S-adenosylmethionine, which function as osmolytes and stress-response compounds, under both the conditions. Our extensive analyses reveal that the high iWUE of Erianthus may be due to the specific accumulation of such metabolites in the leaves, in addition to the low stomatal density on the abaxial side of leaves. The identification of drought-tolerance traits of Erianthus will benefit the generation of sugarcane varieties capable of withstanding drought stress.
Assuntos
Secas , Folhas de Planta , Saccharum , Saccharum/genética , Saccharum/fisiologia , Saccharum/metabolismo , Folhas de Planta/fisiologia , Folhas de Planta/metabolismo , Folhas de Planta/genética , Estômatos de Plantas/fisiologia , Estresse Fisiológico , Água/metabolismo , Água/fisiologia , Transpiração Vegetal/fisiologiaRESUMO
A fundamental assumption in plant science posits that leaf air spaces remain vapor saturated, leading to the predominant view that stomata alone control leaf water loss. This concept has been pivotal in photosynthesis and water-use efficiency research. However, recent evidence has refuted this longstanding assumption by providing evidence of unsaturation in the leaf air space of C3 plants under relatively mild vapor pressure deficit (VPD) stress. This phenomenon represents a nonstomatal mechanism restricting water loss from the mesophyll. The potential ubiquity and physiological implications of this phenomenon, its driving mechanisms in different plant species and habitats, and its interaction with other ecological adaptations have. In this context, C4 plants spark particular interest for their importance as crops, bundle sheath cells' unique anatomical characteristics and specialized functions, and notably higher water-use efficiency relative to C3 plants. Here, we confirm reduced relative humidities in the substomatal cavity of the C4 plants maize, sorghum, and proso millet down to 80% under mild VPD stress. We demonstrate the critical role of nonstomatal control in these plants, indicating that the role of the CO2 concentration mechanism in CO2 management at a high VPD may have been overestimated. Our findings offer a mechanistic reconciliation between discrepancies in CO2 and VPD responses reported in C4 species. They also reveal that nonstomatal control is integral to maintaining an advantageous microclimate of relatively higher CO2 concentrations in the mesophyll air space of C4 plants for carbon fixation, proving vital when these plants face VPD stress.
Assuntos
Células do Mesofilo , Fotossíntese , Pressão de Vapor , Zea mays , Células do Mesofilo/metabolismo , Zea mays/fisiologia , Zea mays/metabolismo , Fotossíntese/fisiologia , Folhas de Planta/metabolismo , Folhas de Planta/fisiologia , Água/metabolismo , Estresse Fisiológico/fisiologia , Dióxido de Carbono/metabolismo , Sorghum/metabolismo , Sorghum/fisiologia , Estômatos de Plantas/fisiologia , Estômatos de Plantas/metabolismoRESUMO
MAIN CONCLUSION: PATOL1 contributes to increasing biomass not only by effective stomatal movement but also by root meristematic activity. PATROL1 (PROTON ATPase TRANSLOCATION CONTROL 1), a protein with a MUN domain, is involved in the intercellular trafficking of AHA1 H+-ATPase to the plasma membrane in guard cells. This allows for larger stomatal opening and more efficient photosynthesis, leading to increased biomass. Although PATROL1 is expressed not only in stomata but also in other tissues of the shoot and root, the role in other tissues than stomata has not been determined yet. Here, we investigated PATROL1 functions in roots using a loss-of-function mutant and an overexpressor. Cytological observations revealed that root meristematic size was significantly smaller in the mutant resulting in the short primary root. Grafting experiments showed that the shoot biomass of the mutant scion was increased when it grafted onto wild-type or overexpressor rootstocks. Conversely, grafting of the overexpressor scion shoot enhanced the growth of the mutant rootstock. The leaf temperatures of the grafted plants were consistent with those of their respective genotypes, indicating cell-autonomous behavior of stomatal movement and independent roles of PATROL1 in plant growth. Moreover, plasma membrane localization of AHA1 was not altered in root epidermal cells in the patrol1 mutant implying existence of a different mode of PATROL1 action in roots. Thus PATROL1 plays a role in root meristem and contributes to increase shoot biomass.
Assuntos
Proteínas de Arabidopsis , Arabidopsis , Biomassa , Raízes de Plantas , Brotos de Planta , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/genética , Raízes de Plantas/metabolismo , Raízes de Plantas/fisiologia , Brotos de Planta/crescimento & desenvolvimento , Brotos de Planta/genética , Brotos de Planta/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/fisiologia , Arabidopsis/metabolismo , Estômatos de Plantas/fisiologia , Estômatos de Plantas/genética , Estômatos de Plantas/crescimento & desenvolvimento , ATPases Translocadoras de Prótons/metabolismo , ATPases Translocadoras de Prótons/genética , Meristema/crescimento & desenvolvimento , Meristema/genética , Meristema/fisiologia , Membrana Celular/metabolismo , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/genética , Folhas de Planta/metabolismo , Folhas de Planta/fisiologia , Regulação da Expressão Gênica de Plantas , MutaçãoRESUMO
Increased temperatures are altering rates of organic matter (OM) breakdown in stream ecosystems with implications for carbon (C) cycling in the face of global change. The metabolic theory of ecology (MTE) provides a framework for predicting temperature effects on OM breakdown, but differences in the temperature dependence of breakdown driven by different organismal groups (i.e., microorganisms vs. invertebrate detritivores) and litter species remain unresolved. Over two years, we conducted 12 60-day leaf litterbag incubations in 20 headwater streams in the southern Appalachian Mountains (USA). We compared temperature dependence (as activation energy, Ea) between microbial and detritivore-mediated breakdown, and between a highly recalcitrant (Rhododendron maximum) and a relatively labile (Acer rubrum) leaf species. Detritivore-mediated breakdown had a higher Ea than microbial breakdown for both leaf species (Rhododendron: 1.48 > 0.56 eV; Acer: 0.97 > 0.29 eV), and Rhododendron breakdown had a higher Ea than Acer breakdown for both organismal groups. Similarly, the Ea of total (coarse-mesh) Rhododendron breakdown was higher than the Ea of total Acer breakdown (0.89 > 0.52 eV). These effects for total breakdown were large, implying that the number of days to 95% mass loss would decline by 40% for Rhododendron and 26% for Acer between 12°C (our mean temperature value) and 16°C (+4°C, reflecting projected increases in global surface temperature due to climate change). Despite patterns in Ea, overall breakdown rates were higher for microbes than detritivores, and for Acer than Rhododendron over most of our temperature gradient. Additionally, the Ea for a subset of the microbial breakdown data declined from 0.40 to 0.22 eV when fungal biomass was included as a model predictor, highlighting the key role of fungi in determining the temperature dependence of litter breakdown. Our results imply that, as streams warm, routing of leaf litter C to detritivore-mediated fates will increase faster than predicted by previous studies and MTE, especially for labile litter. As temperatures rise, earlier depletion of autumn-shed, labile leaf litter combined with rapid breakdown rates of recalcitrant litter could exacerbate seasonal resource limitation and alter carbon storage and transport dynamics in temperate headwater stream networks.
Assuntos
Folhas de Planta , Rhododendron , Rios , Temperatura , Folhas de Planta/fisiologia , Rhododendron/fisiologia , Animais , Especificidade da Espécie , Acer/fisiologia , Invertebrados/fisiologia , Bactérias/classificaçãoRESUMO
MAIN CONCLUSION: The leaf color asymmetry found in the reciprocal hybrids C. hystrix × C. sativus (HC) and C. sativus × C. hystrix (CH) could be influenced by the CsPPR gene (CsaV3_1G038250.1). Most angiosperm organelles are maternally inherited; thus, the reciprocal hybrids usually exhibit asymmetric phenotypes that are associated with the maternal parent. However, there are two sets of organelle genomes in the plant cytoplasm, and the mechanism of reciprocal differences are more complex and largely unknown, because the chloroplast genes are involved besides mitochondrial genes. Cucumis spp. contains the species, i.e., cucumber and melon, which chloroplasts and mitochondria are maternally inherited and paternally inherited, respectively, serving as good materials for the study of reciprocal differences. In this study, leaf color asymmetry was observed in the reciprocal hybrids (HC and CH) derived from C. sativus (2n = 14, CC) and C. hystrix (2n = 24, HH), where the leaves of HC were found to have reduced chlorophyll content, abnormal chloroplast structure and lower photosynthetic capacity. Transcriptomic analysis revealed that the chloroplast development-related genes were differentially expressed in leaf color asymmetry. Genetic analysis showed that leaf color asymmetry was caused by the maternal chloroplast genome. Comparative analysis of chloroplast genomes revealed that there was no mutation in the chloroplast genome during interspecific hybridization. Moreover, a PPR gene (CsaV3_1G038250.1) with RNA-editing function was found to be involved in the regulation of leaf color asymmetry. These findings provide new insights into the regulatory mechanisms of asymmetric phenotypes in plant reciprocal crosses.
Assuntos
Cloroplastos , Cucumis sativus , Folhas de Planta , Edição de RNA , Cucumis sativus/genética , Cucumis sativus/fisiologia , Cucumis sativus/anatomia & histologia , Folhas de Planta/genética , Folhas de Planta/anatomia & histologia , Folhas de Planta/fisiologia , Cloroplastos/genética , Edição de RNA/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Hibridização Genética , Fotossíntese/genética , Fenótipo , Clorofila/metabolismoRESUMO
The ability of plants to retain nitrogen (N) for a long period of time is critical to their N use efficiency, growth, and fitness, particularly in infertile environments. The mean residence time of leaf N (MRTL) and its two determinants, leaf lifespan and N resorption efficiency (rN, the fraction of the total leaf N pool that is resorbed during leaf senescence), have been hypothesized to increase plastically with decreasing soil N fertility but this remains to be fully tested. To avoid confusion by random changes in these characteristics in a relatively narrow N fertility range, MRTL, leaf lifespan, and N resorption efficiency were measured in Quercus glauca over a broad N fertility range. In the high to moderate N fertility range, leaf lifespan and rN increased with decreasing N addition rate, and thus the MRTL increased. However, in the moderate to low N fertility range, leaf lifespan increased but rN decreased significantly, so MRTL decreased. The decrease in rN occurred because the senesced leaf N concentration was almost constant at the lower limit while the green leaf N concentration decreased in this range. The hump-shaped quadratic responses of MRTL and rN along the N fertility gradient suggest that incorrect conclusions about the response of these traits to N fertility variation may be drawn from experiments that include only a few fertility levels, and N recycling within leaf canopy alone cannot achieve efficient N use in infertile environments.
Assuntos
Nitrogênio , Folhas de Planta , Quercus , Solo , Folhas de Planta/fisiologia , Folhas de Planta/metabolismo , Nitrogênio/metabolismo , Quercus/fisiologia , Quercus/metabolismo , Solo/química , Árvores/fisiologia , Árvores/metabolismo , Senescência Vegetal/fisiologiaRESUMO
BACKGROUND: High GABA levels and its conversion to succinate via the GABA shunt are known to be associated with abiotic and biotic stress tolerance in plants. The exact mode of action is still under debate and it is not yet clear whether GABA is a common component of the plant stress defense process or not. We hypothesized that if it is a common route for stress tolerance, activation of GABA-shunt by a biotic stressor might also function in increased abiotic stress tolerance. To test this, Brassica napus plants treated with Flagellin-22 (Flg-22) were exposed to drought stress and the differences in GABA levels along with GABA-shunt components (biosynthetic and catabolic enzyme activities) in the leaf and root samples were compared. In order to provide a better outlook, MYC2, MPK6 and ZAT12, expression profiles were also analyzed since these genes were recently proposed to function in abiotic and biotic stress tolerance. RESULTS: Briefly, we found that Flg treatment increased drought stress tolerance in B. napus via GABA-shunt and the MAPK cascade was involved while the onset was different between leaves and roots. Flg treatment promoted GABA biosynthesis with increased GABA content and GAD activity in the leaves. Better performance of the Flg treated plants under drought stress might be dependent on the activation of GABA-shunt which provides succinate to TCA since GABA-T and SSADH activities were highly induced in the leaves and roots. In the transcript analysis, Flg + drought stressed groups had higher MYC2 transcript abundances correlated well with the GABA content and GABA-shunt while, MPK6 expression was induced only in the roots of the Flg + drought stressed groups. ZAT12 was also induced both in leaves and roots as a result of Flg-22 treatment. However, correlation with GABA and GABA-shunt could be proposed only in Flg + drought stressed group. CONCLUSION: We provided solid data on how GABA-shunt and Fgl-22 are interacting against abiotic stress in leaf and root tissues. Fgl-22 induced ETI activated GABA-shunt with a plausible cross talk between MYC2 and ZAT12 transcription factors for drought stress tolerance in B. napus.
Assuntos
Brassica napus , Secas , Flagelina , Ácido gama-Aminobutírico , Brassica napus/genética , Brassica napus/fisiologia , Brassica napus/efeitos dos fármacos , Brassica napus/metabolismo , Ácido gama-Aminobutírico/metabolismo , Flagelina/farmacologia , Estresse Fisiológico/genética , Regulação da Expressão Gênica de Plantas , Raízes de Plantas/metabolismo , Raízes de Plantas/fisiologia , Raízes de Plantas/genética , Folhas de Planta/metabolismo , Folhas de Planta/fisiologia , Folhas de Planta/genética , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genéticaRESUMO
The water relation strategy is a key issue in climate change. Given the difficulty of determining water relations strategy, there is a need for simple traits with a solid theoretical basis to estimate it. Traits associated with resource allocation patterns along a 'fast-slow' plant economics spectrum are particularly compelling, reflecting trade-offs between growth rate and carbon allocation. Avocado (Persea americana ), fig tree (Ficus carica ), mandarin (Citrus reticulata ), olive (Olea europaea ), pomegranate (Punica granatum ), and grapevine (Vitis vinifera ) were characterised in terms of iso-anisohydric strategy through stomatal behaviour, water potential at the turgor loss point (TLP), and hydroscape area. Additionally, the association of these metrics with leaf mass per area (LMA) and wood density (WDen) was explored. We observed high coordination between LMA and WDen, and both traits were related to metrics of water relation strategy. More anisohydric species tended to invest more carbon per unit leaf area or unit stem volume, which has implications for hydraulic efficiency and water stress tolerance. WDen and TLP were the most powerful traits in estimating the water relation strategy for six fruit species. These traits are easy to measure, time-cost efficient, and appear central to coordinating multiple traits and behaviours along the water relations strategies.
Assuntos
Carbono , Folhas de Planta , Caules de Planta , Árvores , Água , Folhas de Planta/fisiologia , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/anatomia & histologia , Folhas de Planta/metabolismo , Água/metabolismo , Carbono/metabolismo , Caules de Planta/crescimento & desenvolvimento , Caules de Planta/fisiologia , Caules de Planta/anatomia & histologia , Árvores/crescimento & desenvolvimento , Árvores/fisiologia , Persea/fisiologia , Persea/crescimento & desenvolvimento , Citrus/crescimento & desenvolvimento , Citrus/fisiologia , Citrus/anatomia & histologia , Frutas/crescimento & desenvolvimento , Vitis/crescimento & desenvolvimento , Vitis/fisiologia , Olea/fisiologia , Olea/crescimento & desenvolvimento , Ficus/fisiologia , Ficus/crescimento & desenvolvimento , Punica granatumRESUMO
Leaf senescence is a crucial process throughout evolution, vital for plant fitness as it facilitates the gradual shift of energy allocation between photosynthesis and catabolism overtime. This onset is influenced by a complex interplay of genetic and environmental factors, making senescence a key adaptation mechanism for plants in their natural habitats. Our study investigated the genetic mechanism underlying age-induced leaf senescence in Arabidopsis natural populations. Using a phenome high-throughput investigator, we comprehensively analyzed senescence responses across 234 Arabidopsis accessions and identified that environmental factors (e.g., ambient temperature) and physiological factors (e.g., defense responses) are substantially linked to senescence phenotypes. Through genome-wide association mapping, we identified the ACCELERATED CELL DEATH 6 (ACD6) locus as a potential regulator of senescence variation among natural accessions. Knocking out ACD6 in accessions with early and delayed senescence phenotypes resulted in varying degrees of delay in age-induced senescence, highlighting the accession-dependent regulatory role of ACD6 in leaf senescence. Furthermore, our findings suggest ACD6's involvement in senescence regulation via the salicylic acid signaling pathway. In summary, our study sheds light on the genetic regulation of leaf senescence in Arabidopsis natural populations, with the discovery of ACD6 as a potential candidate for genetic modification to enhance plant adaptation and survival.
Assuntos
Proteínas de Arabidopsis , Arabidopsis , Folhas de Planta , Senescência Vegetal , Ácido Salicílico , Arabidopsis/genética , Arabidopsis/fisiologia , Folhas de Planta/genética , Folhas de Planta/fisiologia , Folhas de Planta/efeitos dos fármacos , Ácido Salicílico/metabolismo , Ácido Salicílico/farmacologia , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Senescência Vegetal/genética , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Fenótipo , Estudo de Associação Genômica Ampla , Transdução de Sinais , AnquirinasRESUMO
Climate change will bring the interaction of stresses such as increased temperature and drought under high [CO2] conditions. This is likely to impact on crop growth and productivity. This study aimed to (i) determine the response of barley water relations to vegetative and anthesis drought periods under triple interaction conditions, (ii) test the possibility to prime barley plants for drought, and (iii) analyse the involvement of aquaporins in (i) and (ii). The water status of barley was not affected by drought at the vegetative stage, regardless of the environmental conditions. At the anthesis stage, when the water shortage period was more severe, barley plants growing under combined elevated CO2 and temperature conditions were able to maintain a better water status compared with plants grown under current conditions. Elevated CO2 and temperature conditions reduced the stomatal conductance and slowed down the plant water flow through a root-leaf hydraulic conductivity coordination. Leaf HvPIP2;1 and HvTIP1;1 aquaporins seemed to play a key role regulating barley's water flow, while leaf and root HvPIP2;5 provided basic level of water flow. At anthesis drought and under future combined conditions, plants showed a reduced cell dehydration and decrease in leaf relative water content compared with plants grown under current conditions. Exposure to a previous drought did not prime the water status of barley plants to a subsequent drought, but instead worsened the response under future conditions. This was due to an imbalance between the roots versus shoot development.
Assuntos
Mudança Climática , Secas , Hordeum , Água , Hordeum/metabolismo , Hordeum/fisiologia , Hordeum/crescimento & desenvolvimento , Água/metabolismo , Aquaporinas/metabolismo , Folhas de Planta/metabolismo , Folhas de Planta/fisiologia , Dióxido de Carbono/metabolismo , Proteínas de Plantas/metabolismo , Raízes de Plantas/metabolismo , Raízes de Plantas/fisiologia , Raízes de Plantas/crescimento & desenvolvimentoRESUMO
KEY MESSAGE: Natural transformation with R. rhizogenes enhances osmotic stress tolerance in oilseed rape through increasing osmoregulation capacity, enhancing maintenance of hydraulic integrity and total antioxidant capacity. Transformation of plants using wild strains of agrobacteria is termed natural transformation and is not covered by GMO legislation in, e.g., European Union and Japan. In this study, offspring lines of Rhizobium rhizogenes naturally transformed oilseed rape (Brassica napus), i.e., A11 and B3 (termed root-inducing (Ri) lines), were investigated for osmotic stress resilience. Under polyethylene glycol 6000 (PEG) 10% (w/v)-induced osmotic stress, the Ri lines, particularly A11, had less severe leaf wilting, higher stomatal conductance (8.2 times more than WT), and a stable leaf transpiration rate (about 2.9 mmol m-2 s-1). Although the leaf relative water content and leaf water potential responded similarly to PEG treatment between the Ri lines and WT, a significant reduction of the turgid weight to dry weight ratio in A11 and B3 indicated a greater capacity of osmoregulation in the Ri lines. Moreover, the upregulation of plasma membrane intrinsic proteins genes (PIPs) in roots and downregulation of these genes in leaves of the Ri lines implied a better maintenance of hydraulic integrity in relation to the WT. Furthermore, the Ri lines had greater total antioxidant capacity (TAC) than the WT under PEG stress. Collectively, the enhanced tolerance of the Ri lines to PEG-induced osmotic stress could be attributed to the greater osmoregulation capacity, better maintenance of hydraulic integrity, and greater TAC than the WT. In addition, Ri-genes (particularly rolA and rolD) play roles in response to osmotic stress in Ri oilseed rape. This study reveals the potential of R. rhizogenes transformation for application in plant drought resilience.