RESUMEN
The carnivorous plant Utricularia gibba forms cup-shaped leaflets to capture prey. Whitewoods et al. (2020) use computational modeling to simulate the formation of the trap's 3D geometry. Directional expansion of the young leaflet is proposed to be a crucial morphogenetic driver, pointing at a fundamental principle of plant development.
Asunto(s)
Lamiales/genética , Expresión Génica , Desarrollo de la Planta , Hojas de la PlantaRESUMEN
In response to biotic stress, plants produce suites of highly modified fatty acids that bear unusual chemical functionalities. Despite their chemical complexity and proposed roles in pathogen defense, little is known about the biosynthesis of decorated fatty acids in plants. Falcarindiol is a prototypical acetylenic lipid present in carrot, tomato, and celery that inhibits growth of fungi and human cancer cell lines. Using a combination of untargeted metabolomics and RNA sequencing, we discovered a biosynthetic gene cluster in tomato (Solanum lycopersicum) required for falcarindiol production. By reconstituting initial biosynthetic steps in a heterologous host and generating transgenic pathway mutants in tomato, we demonstrate a direct role of the cluster in falcarindiol biosynthesis and resistance to fungal and bacterial pathogens in tomato leaves. This work reveals a mechanism by which plants sculpt their lipid pool in response to pathogens and provides critical insight into the complex biochemistry of alkynyl lipid production.
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Diinos/metabolismo , Ácidos Grasos/biosíntesis , Alcoholes Grasos/metabolismo , Solanum lycopersicum/genética , Resistencia a la Enfermedad/genética , Diinos/química , Ácidos Grasos/metabolismo , Alcoholes Grasos/química , Regulación de la Expresión Génica de las Plantas/genética , Metabolómica , Familia de Multigenes/genética , Enfermedades de las Plantas/microbiología , Hojas de la Planta/metabolismo , Proteínas de Plantas/metabolismo , Plantas Modificadas Genéticamente , Estrés Fisiológico/genéticaRESUMEN
How do genes modify cellular growth to create morphological diversity? We study this problem in two related plants with differently shaped leaves: Arabidopsis thaliana (simple leaf shape) and Cardamine hirsuta (complex shape with leaflets). We use live imaging, modeling, and genetics to deconstruct these organ-level differences into their cell-level constituents: growth amount, direction, and differentiation. We show that leaf shape depends on the interplay of two growth modes: a conserved organ-wide growth mode that reflects differentiation; and a local, directional mode that involves the patterning of growth foci along the leaf edge. Shape diversity results from the distinct effects of two homeobox genes on these growth modes: SHOOTMERISTEMLESS broadens organ-wide growth relative to edge-patterning, enabling leaflet emergence, while REDUCED COMPLEXITY inhibits growth locally around emerging leaflets, accentuating shape differences created by patterning. We demonstrate the predictivity of our findings by reconstructing key features of C. hirsuta leaf morphology in A. thaliana. VIDEO ABSTRACT.
Asunto(s)
Arabidopsis/crecimiento & desarrollo , Cardamine/crecimiento & desarrollo , Hojas de la Planta/crecimiento & desarrollo , Arabidopsis/genética , Cardamine/genética , Linaje de la Célula/genética , Biología Computacional/métodos , Regulación de la Expresión Génica de las Plantas/genética , Hojas de la Planta/genética , Proteínas de Plantas/metabolismoRESUMEN
Following a previous microbial inoculation, plants can induce broad-spectrum immunity to pathogen infection, a phenomenon known as systemic acquired resistance (SAR). SAR establishment in Arabidopsis thaliana is regulated by the Lys catabolite pipecolic acid (Pip) and flavin-dependent-monooxygenase1 (FMO1). Here, we show that elevated Pip is sufficient to induce an FMO1-dependent transcriptional reprogramming of leaves that is reminiscent of SAR. In planta and in vitro analyses demonstrate that FMO1 functions as a pipecolate N-hydroxylase, catalyzing the biochemical conversion of Pip to N-hydroxypipecolic acid (NHP). NHP systemically accumulates in plants after microbial attack. When exogenously applied, it overrides the defect of NHP-deficient fmo1 in acquired resistance and acts as a potent inducer of plant immunity to bacterial and oomycete infection. Our work has identified a pathogen-inducible L-Lys catabolic pathway in plants that generates the N-hydroxylated amino acid NHP as a critical regulator of systemic acquired resistance to pathogen infection.
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Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Oxigenasas/metabolismo , Ácidos Pipecólicos/metabolismo , Inmunidad de la Planta/efectos de los fármacos , Arabidopsis/enzimología , Arabidopsis/inmunología , Proteínas de Arabidopsis/genética , Cromatografía de Gases y Espectrometría de Masas , Lisina/metabolismo , Oomicetos/patogenicidad , Oxigenasas/genética , Ácidos Pipecólicos/análisis , Ácidos Pipecólicos/farmacología , Hojas de la Planta/enzimología , Hojas de la Planta/inmunología , Hojas de la Planta/metabolismo , Pseudomonas syringae/patogenicidad , Transaminasas/genética , Transaminasas/metabolismoRESUMEN
Increasing planting density is a key strategy for enhancing maize yields1-3. An ideotype for dense planting requires a 'smart canopy' with leaf angles at different canopy layers differentially optimized to maximize light interception and photosynthesis4-6, among other features. Here we identified leaf angle architecture of smart canopy 1 (lac1), a natural mutant with upright upper leaves, less erect middle leaves and relatively flat lower leaves. lac1 has improved photosynthetic capacity and attenuated responses to shade under dense planting. lac1 encodes a brassinosteroid C-22 hydroxylase that predominantly regulates upper leaf angle. Phytochrome A photoreceptors accumulate in shade and interact with the transcription factor RAVL1 to promote its degradation via the 26S proteasome, thereby inhibiting activation of lac1 by RAVL1 and decreasing brassinosteroid levels. This ultimately decreases upper leaf angle in dense fields. Large-scale field trials demonstrate that lac1 boosts maize yields under high planting densities. To quickly introduce lac1 into breeding germplasm, we transformed a haploid inducer and recovered homozygous lac1 edits from 20 diverse inbred lines. The tested doubled haploids uniformly acquired smart-canopy-like plant architecture. We provide an important target and an accelerated strategy for developing high-density-tolerant cultivars, with lac1 serving as a genetic chassis for further engineering of a smart canopy in maize.
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Brasinoesteroides , Fotosíntesis , Hojas de la Planta , Zea mays , Zea mays/crecimiento & desarrollo , Zea mays/genética , Hojas de la Planta/metabolismo , Hojas de la Planta/crecimiento & desarrollo , Brasinoesteroides/metabolismo , Fitocromo A/metabolismo , Fitocromo A/genética , Complejo de la Endopetidasa Proteasomal/metabolismo , Haploidia , Homocigoto , Mutación , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , LuzRESUMEN
The critical temperature beyond which photosynthetic machinery in tropical trees begins to fail averages approximately 46.7 °C (Tcrit)1. However, it remains unclear whether leaf temperatures experienced by tropical vegetation approach this threshold or soon will under climate change. Here we found that pantropical canopy temperatures independently triangulated from individual leaf thermocouples, pyrgeometers and remote sensing (ECOSTRESS) have midday peak temperatures of approximately 34 °C during dry periods, with a long high-temperature tail that can exceed 40 °C. Leaf thermocouple data from multiple sites across the tropics suggest that even within pixels of moderate temperatures, upper canopy leaves exceed Tcrit 0.01% of the time. Furthermore, upper canopy leaf warming experiments (+2, 3 and 4 °C in Brazil, Puerto Rico and Australia, respectively) increased leaf temperatures non-linearly, with peak leaf temperatures exceeding Tcrit 1.3% of the time (11% for more than 43.5 °C, and 0.3% for more than 49.9 °C). Using an empirical model incorporating these dynamics (validated with warming experiment data), we found that tropical forests can withstand up to a 3.9 ± 0.5 °C increase in air temperatures before a potential tipping point in metabolic function, but remaining uncertainty in the plasticity and range of Tcrit in tropical trees and the effect of leaf death on tree death could drastically change this prediction. The 4.0 °C estimate is within the 'worst-case scenario' (representative concentration pathway (RCP) 8.5) of climate change predictions2 for tropical forests and therefore it is still within our power to decide (for example, by not taking the RCP 6.0 or 8.5 route) the fate of these critical realms of carbon, water and biodiversity3,4.
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Aclimatación , Calor Extremo , Bosques , Fotosíntesis , Árboles , Clima Tropical , Aclimatación/fisiología , Australia , Brasil , Calor Extremo/efectos adversos , Calentamiento Global , Fotosíntesis/fisiología , Puerto Rico , Desarrollo Sostenible/legislación & jurisprudencia , Desarrollo Sostenible/tendencias , Árboles/fisiología , Hojas de la Planta/fisiología , IncertidumbreRESUMEN
As the climate changes, warmer spring temperatures are causing earlier leaf-out1-3 and commencement of CO2 uptake1,3 in temperate deciduous forests, resulting in a tendency towards increased growing season length3 and annual CO2 uptake1,3-7. However, less is known about how spring temperatures affect tree stem growth8,9, which sequesters carbon in wood that has a long residence time in the ecosystem10,11. Here we show that warmer spring temperatures shifted stem diameter growth of deciduous trees earlier but had no consistent effect on peak growing season length, maximum growth rates, or annual growth, using dendrometer band measurements from 440 trees across two forests. The latter finding was confirmed on the centennial scale by 207 tree-ring chronologies from 108 forests across eastern North America, where annual ring width was far more sensitive to temperatures during the peak growing season than in the spring. These findings imply that any extra CO2 uptake in years with warmer spring temperatures4,5 does not significantly contribute to increased sequestration in long-lived woody stem biomass. Rather, contradicting projections from global carbon cycle models1,12, our empirical results imply that warming spring temperatures are unlikely to increase woody productivity enough to strengthen the long-term CO2 sink of temperate deciduous forests.
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Calentamiento Global , Estaciones del Año , Temperatura , Árboles , Aclimatación , Biomasa , Dióxido de Carbono/metabolismo , Secuestro de Carbono , Modelos Climáticos , Bosques , Calentamiento Global/estadística & datos numéricos , América del Norte , Hojas de la Planta/crecimiento & desarrollo , Hojas de la Planta/metabolismo , Tallos de la Planta/crecimiento & desarrollo , Tallos de la Planta/metabolismo , Factores de Tiempo , Árboles/anatomía & histología , Árboles/clasificación , Árboles/crecimiento & desarrollo , Árboles/metabolismo , Madera/crecimiento & desarrollo , Madera/metabolismoRESUMEN
Recent observations suggest that the large carbon sink in mature and recovering forests may be strongly limited by nitrogen1-3. Nitrogen-fixing trees (fixers) in symbiosis with bacteria provide the main natural source of new nitrogen to tropical forests3,4. However, abundances of fixers are tightly constrained5-7, highlighting the fundamental unanswered question of what limits new nitrogen entering tropical ecosystems. Here we examine whether herbivory by animals is responsible for limiting symbiotic nitrogen fixation in tropical forests. We evaluate whether nitrogen-fixing trees experience more herbivory than other trees, whether herbivory carries a substantial carbon cost, and whether high herbivory is a result of herbivores targeting the nitrogen-rich leaves of fixers8,9. We analysed 1,626 leaves from 350 seedlings of 43 tropical tree species in Panama and found that: (1) although herbivory reduces the growth and survival of all seedlings, nitrogen-fixing trees undergo 26% more herbivory than non-fixers; (2) fixers have 34% higher carbon opportunity costs owing to herbivory than non-fixers, exceeding the metabolic cost of fixing nitrogen; and (3) the high herbivory of fixers is not driven by high leaf nitrogen. Our findings reveal that herbivory may be sufficient to limit tropical symbiotic nitrogen fixation and could constrain its role in alleviating nitrogen limitation on the tropical carbon sink.
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Bosques , Herbivoria , Fijación del Nitrógeno , Nitrógeno , Árboles , Clima Tropical , Animales , Carbono/metabolismo , Secuestro de Carbono , Nitrógeno/metabolismo , Panamá , Hojas de la Planta , Plantones , Árboles/clasificación , Árboles/metabolismoRESUMEN
The efficiency of solar radiation interception contributes to the photosynthetic efficiency of crop plants. Light interception is a function of canopy architecture, including plant density; leaf number, length, width, and angle; and azimuthal canopy orientation. We report on the ability of some maize (Zea mays) genotypes to alter the orientations of their leaves during development in coordination with adjacent plants. Although the upper canopies of these genotypes retain the typical alternate-distichous phyllotaxy of maize, their leaves grow parallel to those of adjacent plants. A genome-wide association study (GWAS) on this parallel canopy trait identified candidate genes, many of which are associated with shade avoidance syndrome, including phytochromeC2. GWAS conducted on the fraction of photosynthetically active radiation (PAR) intercepted by canopies also identified multiple candidate genes, including liguleless1 (lg1), previously defined by its role in ligule development. Under high plant densities, mutants of shade avoidance syndrome and liguleless genes (lg1, lg2, and Lg3) exhibit altered canopy patterns, viz, the numbers of interrow leaves are greatly reduced as compared to those of nonmutant controls, resulting in dramatically decreased PAR interception. In at least the case of lg2, this phenotype is not a consequence of abnormal ligule development. Instead, liguleless gene functions are required for normal light responses, including azimuth canopy re-orientation.
Asunto(s)
Estudio de Asociación del Genoma Completo , Luz , Fotosíntesis , Hojas de la Planta , Zea mays , Zea mays/genética , Zea mays/efectos de la radiación , Zea mays/crecimiento & desarrollo , Hojas de la Planta/genética , Hojas de la Planta/efectos de la radiación , Hojas de la Planta/crecimiento & desarrollo , Fotosíntesis/genética , Fotosíntesis/efectos de la radiación , Genotipo , Regulación de la Expresión Génica de las Plantas , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , FenotipoRESUMEN
The milestone of compound leaf development is the generation of separate leaflet primordia during the early stages, which involves two linked but distinct morphogenetic events: leaflet initiation and boundary establishment for leaflet separation. Although some progress in understanding the regulatory pathways for each event have been made, it is unclear how they are intrinsically coordinated. Here, we identify the PINNATE-LIKE PENTAFOLIATA2 (PINNA2) gene encoding a newly identified GRAS transcription factor in Medicago truncatula. PINNA2 transcripts are preferentially detected at organ boundaries. Its loss-of-function mutations convert trifoliate leaves into a pinnate pentafoliate pattern. PINNA2 directly binds to the promoter region of the LEAFY orthologue SINGLE LEAFLET1 (SGL1), which encodes a key positive regulator of leaflet initiation, and downregulates its expression. Further analysis revealed that PINNA2 synergizes with two other repressors of SGL1 expression, the BEL1-like homeodomain protein PINNA1 and the C2H2 zinc finger protein PALMATE-LIKE PENTAFOLIATA1 (PALM1), to precisely define the spatiotemporal expression of SGL1 in compound leaf primordia, thereby maintaining a proper pattern of leaflet initiation. Moreover, we showed that the enriched expression of PINNA2 at the leaflet-to-leaflet boundaries is positively regulated by the boundary-specific gene MtNAM, which is essential for leaflet boundary formation. Together, these results unveil a pivotal role of the boundary-expressed transcription factor PINNA2 in regulating leaflet initiation, providing molecular insights into the coordination of intricate developmental processes underlying compound leaf pattern formation.
Asunto(s)
Regulación de la Expresión Génica de las Plantas , Medicago truncatula , Hojas de la Planta , Medicago truncatula/genética , Medicago truncatula/crecimiento & desarrollo , Medicago truncatula/metabolismo , Morfogénesis/genética , Hojas de la Planta/genética , Hojas de la Planta/crecimiento & desarrollo , Hojas de la Planta/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Modificadas Genéticamente , Regiones Promotoras Genéticas/genética , Factores de Transcripción/metabolismo , Factores de Transcripción/genéticaRESUMEN
Cucumber (Cucumis sativus, Cs) tendrils are slender vegetative organs that typically require manual removal to ensure orderly growth during greenhouse cultivation. Here, we identified cucumber tendril-less (tl), a Tnt1 retrotransposon-induced insertion mutant lacking tendrils. Map-based cloning identified the mutated gene, CsaV3_3G003590, which we designated as CsTL, which is homologous to Arabidopsis thaliana LATERAL SUPPRESSOR (AtLAS). Knocking out CsTL repressed tendril formation but did not affect branch initiation, whereas overexpression (OE) of CsTL resulted in the formation of two or more tendrils in one leaf axil. Although expression of two cucumber genes regulating tendril formation, Tendril (CsTEN) and Unusual Floral Organs (CsUFO), was significantly decreased in CsTL knockout lines, these two genes were not direct downstream targets of CsTL. Instead, CsTL physically interacted with CsTEN, an interaction that further enhanced CsTEN-mediated expression of CsUFO. In Arabidopsis, the CsTL homolog AtLAS acts upstream of REVOLUTA (REV) to regulate branch initiation. Knocking out cucumber CsREV inhibited branch formation without affecting tendril initiation. Furthermore, genomic regions containing CsTL and AtLAS were not syntenic between the cucumber and Arabidopsis genomes, whereas REV orthologs were found on a shared syntenic block. Our results revealed not only that cucumber CsTL possesses a divergent function in promoting tendril formation but also that CsREV retains its conserved function in shoot branching.
Asunto(s)
Arabidopsis , Cucumis sativus , Regulación de la Expresión Génica de las Plantas , Proteínas de Plantas , Factores de Transcripción , Cucumis sativus/genética , Cucumis sativus/crecimiento & desarrollo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Arabidopsis/crecimiento & desarrollo , Plantas Modificadas Genéticamente , Hojas de la Planta/genética , Hojas de la Planta/metabolismo , Hojas de la Planta/crecimiento & desarrolloRESUMEN
Shoot branching affects plant architecture. In strawberry (Fragaria L.), short branches (crowns) develop from dormant axillary buds to form inflorescences and flowers. While this developmental transition contributes greatly to perenniality and yield in strawberry, its regulatory mechanism remains unclear and understudied. In the woodland strawberry (Fragaria vesca), we identified and characterized 2 independent mutants showing more crowns. Both mutant alleles reside in FveMYB117a, a R2R3-MYB transcription factor gene highly expressed in shoot apical meristems, axillary buds, and young leaves. Transcriptome analysis revealed that the expression of several cytokinin pathway genes was altered in the fvemyb117a mutant. Consistently, active cytokinins were significantly increased in the axillary buds of the fvemyb117a mutant. Exogenous application of cytokinin enhanced crown outgrowth in the wild type, whereas the cytokinin inhibitors suppressed crown outgrowth in the fvemyb117a mutant. FveMYB117a binds directly to the promoters of the cytokinin homeostasis genes FveIPT2 encoding an isopentenyltransferase and FveCKX1 encoding a cytokinin oxidase to regulate their expression. Conversely, the type-B Arabidopsis response regulators FveARR1 and FveARR2b can directly inhibit the expression of FveMYB117a, indicative of a negative feedback regulation. In conclusion, we identified FveMYB117a as a key repressor of crown outgrowth by inhibiting cytokinin accumulation and provide a mechanistic basis for bud fate transition in an herbaceous perennial plant.
Asunto(s)
Citocininas , Fragaria , Regulación de la Expresión Génica de las Plantas , Proteínas de Plantas , Factores de Transcripción , Citocininas/metabolismo , Fragaria/genética , Fragaria/crecimiento & desarrollo , Fragaria/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Factores de Transcripción/metabolismo , Factores de Transcripción/genética , Homeostasis , Mutación , Hojas de la Planta/metabolismo , Hojas de la Planta/genética , Hojas de la Planta/crecimiento & desarrollo , Brotes de la Planta/crecimiento & desarrollo , Brotes de la Planta/genética , Brotes de la Planta/metabolismoRESUMEN
Plants have an astonishing ability to regenerate new organs after wounding. Here, we report that the wound-inducible transcription factor ENHANCER OF SHOOT REGENERATION1 (ESR1) has a dual mode of action in activating ANTHRANILATE SYNTHASE ALPHA SUBUNIT1 (ASA1) expression to ensure auxin-dependent de novo root organogenesis locally at wound sites of Arabidopsis (Arabidopsis thaliana) leaf explants. In the first mode, ESR1 interacts with HISTONE DEACETYLASE6 (HDA6), and the ESR1-HDA6 complex directly binds to the JASMONATE-ZIM DOMAIN5 (JAZ5) locus, inhibiting JAZ5 expression through histone H3 deacetylation. As JAZ5 interferes with the action of ETHYLENE RESPONSE FACTOR109 (ERF109), the transcriptional repression of JAZ5 at the wound site allows ERF109 to activate ASA1 expression. In the second mode, the ESR1 transcriptional activator directly binds to the ASA1 promoter to enhance its expression. Overall, our findings indicate that the dual biochemical function of ESR1, which specifically occurs near wound sites of leaf explants, maximizes local auxin biosynthesis and de novo root organogenesis in Arabidopsis.
Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Regulación de la Expresión Génica de las Plantas , Organogénesis de las Plantas , Raíces de Plantas , Factores de Transcripción , Arabidopsis/genética , Arabidopsis/crecimiento & desarrollo , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Histona Desacetilasas/metabolismo , Histona Desacetilasas/genética , Ácidos Indolacéticos/metabolismo , Organogénesis de las Plantas/genética , Hojas de la Planta/genética , Hojas de la Planta/metabolismo , Hojas de la Planta/crecimiento & desarrollo , Raíces de Plantas/crecimiento & desarrollo , Raíces de Plantas/genética , Plantas Modificadas Genéticamente , Regiones Promotoras Genéticas/genética , Factores de Transcripción/metabolismo , Factores de Transcripción/genéticaRESUMEN
Selective partitioning of amino acids among organelles, cells, tissues, and organs is essential for cellular metabolism and plant growth. Nitrogen assimilation into glutamine and glutamate and de novo biosynthesis of most protein amino acids occur in chloroplasts; therefore, various transport mechanisms must exist to accommodate their directional efflux from the stroma to the cytosol and feed the amino acids into the extraplastidial metabolic and long-distance transport pathways. Yet, Arabidopsis (Arabidopsis thaliana) transporters functioning in plastidial export of amino acids remained undiscovered. Here, USUALLY MULTIPLE ACIDS MOVE IN AND OUT TRANSPORTER 44 (UMAMIT44) was identified and shown to function in glutamate export from Arabidopsis chloroplasts. UMAMIT44 controls glutamate homeostasis within and outside of chloroplasts and influences nitrogen partitioning from leaves to sinks. Glutamate imbalances in chloroplasts and leaves of umamit44 mutants impact cellular redox state, nitrogen and carbon metabolism, and amino acid (AA) and sucrose supply of growing sinks, leading to negative effects on plant growth. Nonetheless, the mutant lines adjust to some extent by upregulating alternative pathways for glutamate synthesis outside the plastids and by mitigating oxidative stress through the production of other amino acids and antioxidants. Overall, this study establishes that the role of UMAMIT44 in glutamate export from chloroplasts is vital for controlling nitrogen availability within source leaf cells and for sink nutrition, with an impact on growth and seed yield.
Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Ácido Glutámico , Cloroplastos/metabolismo , Proteínas de Transporte de Membrana/metabolismo , Aminoácidos/metabolismo , Hojas de la Planta/metabolismo , Nitrógeno/metabolismoRESUMEN
Carotenoids are essential for photosynthesis and photoprotection. Plants must evolve multifaceted regulatory mechanisms to control carotenoid biosynthesis. However, the regulatory mechanisms and the regulators conserved among plant species remain elusive. Phytoene synthase (PSY) catalyzes the highly regulated step of carotenogenesis and geranylgeranyl diphosphate synthase (GGPPS) acts as a hub to interact with GGPP-utilizing enzymes for the synthesis of specific downstream isoprenoids. Here, we report a function of Nudix hydrolase 23 (NUDX23), a Nudix domain-containing protein, in post-translational regulation of PSY and GGPPS for carotenoid biosynthesis. NUDX23 expresses highly in Arabidopsis (Arabidopsis thaliana) leaves. Overexpression of NUDX23 significantly increases PSY and GGPPS protein levels and carotenoid production, whereas knockout of NUDX23 dramatically reduces their abundances and carotenoid accumulation in Arabidopsis. NUDX23 regulates carotenoid biosynthesis via direct interactions with PSY and GGPPS in chloroplasts, which enhances PSY and GGPPS protein stability in a large PSY-GGPPS enzyme complex. NUDX23 was found to co-migrate with PSY and GGPPS proteins and to be required for the enzyme complex assembly. Our findings uncover a regulatory mechanism underlying carotenoid biosynthesis in plants and offer promising genetic tools for developing carotenoid-enriched food crops.
Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Carotenoides , Regulación de la Expresión Génica de las Plantas , Carotenoides/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Hidrolasas Nudix , Cloroplastos/metabolismo , Geranilgeranil-Difosfato Geranilgeraniltransferasa/metabolismo , Geranilgeranil-Difosfato Geranilgeraniltransferasa/genética , Farnesiltransferasa/metabolismo , Farnesiltransferasa/genética , Pirofosfatasas/metabolismo , Pirofosfatasas/genética , Procesamiento Proteico-Postraduccional , Plantas Modificadas Genéticamente , Hojas de la Planta/metabolismo , Hojas de la Planta/genéticaRESUMEN
MicroRNAs (miRNAs) are processed from primary transcripts that contain partially self-complementary foldbacks. As in animals, the core microprocessor in plants is a Dicer protein, DICER-LIKE1 (DCL1). Processing accuracy and strand selection is greatly enhanced through the RNA binding protein HYPONASTIC LEAVES 1 (HYL1) and the zinc finger protein SERRATE (SE). We have combined a luciferase-based genetic screen with whole-genome sequencing for rapid identification of new regulators of miRNA biogenesis and action. Among the first six mutants analyzed were three alleles of C-TERMINAL DOMAIN PHOSPHATASE-LIKE 1 (CPL1)/FIERY2 (FRY2). In the miRNA processing complex, SE functions as a scaffold to mediate CPL1 interaction with HYL1, which needs to be dephosphorylated for optimal activity. In the absence of CPL1, HYL1 dephosphorylation and hence accurate processing and strand selection from miRNA duplexes are compromised. Our findings thus define a new regulatory step in plant miRNA biogenesis.
Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , MicroARNs/metabolismo , Fosfoproteínas Fosfatasas/metabolismo , Procesamiento Postranscripcional del ARN , ARN de Planta/metabolismo , Proteínas de Unión al ARN/metabolismo , Factores de Transcripción/metabolismo , Proteínas de Unión al Calcio/metabolismo , Péptidos y Proteínas de Señalización Intercelular/metabolismo , Proteínas de la Membrana/metabolismo , Fosforilación , Hojas de la Planta/metabolismo , Proteínas de Plantas/metabolismo , Proteínas Serrate-Jagged , Nicotiana/metabolismoRESUMEN
One of the most notable ecological trends-described more than 2,300 years ago by Theophrastus-is the association of small leaves with dry and cold climates, which has recently been recognized for eudicotyledonous plants at a global scale1-3. For eudicotyledons, this pattern has been attributed to the fact that small leaves have a thinner boundary layer that helps to avoid extreme leaf temperatures4 and their leaf development results in vein traits that improve water transport under cold or dry climates5,6. However, the global distribution of leaf size and its adaptive basis have not been tested in the grasses, which represent a diverse lineage that is distinct in leaf morphology and that contributes 33% of terrestrial primary productivity (including the bulk of crop production)7. Here we demonstrate that grasses have shorter and narrower leaves under colder and drier climates worldwide. We show that small grass leaves have thermal advantages and vein development that contrast with those of eudicotyledons, but that also explain the abundance of small leaves in cold and dry climates. The worldwide distribution of leaf size in grasses exemplifies how biophysical and developmental processes result in convergence across major lineages in adaptation to climate globally, and highlights the importance of leaf size and venation architecture for grass performance in past, present and future ecosystems.
Asunto(s)
Aclimatación , Cambio Climático , Hojas de la Planta/crecimiento & desarrollo , Poaceae/crecimiento & desarrollo , Agua/metabolismo , Xilema/crecimiento & desarrollo , Fenómenos Biofísicos , Clima , Frío , Sequías , Hojas de la Planta/anatomía & histología , Hojas de la Planta/metabolismo , Poaceae/anatomía & histología , Poaceae/metabolismo , Xilema/anatomía & histología , Xilema/metabolismoRESUMEN
Symbiotic N2-fixing microorganisms have a crucial role in the assimilation of nitrogen by eukaryotes in nitrogen-limited environments1-3. Particularly among land plants, N2-fixing symbionts occur in a variety of distantly related plant lineages and often involve an intimate association between host and symbiont2,4. Descriptions of such intimate symbioses are lacking for seagrasses, which evolved around 100 million years ago from terrestrial flowering plants that migrated back to the sea5. Here we describe an N2-fixing symbiont, 'Candidatus Celerinatantimonas neptuna', that lives inside seagrass root tissue, where it provides ammonia and amino acids to its host in exchange for sugars. As such, this symbiosis is reminiscent of terrestrial N2-fixing plant symbioses. The symbiosis between Ca. C. neptuna and its host Posidonia oceanica enables highly productive seagrass meadows to thrive in the nitrogen-limited Mediterranean Sea. Relatives of Ca. C. neptuna occur worldwide in coastal ecosystems, in which they may form similar symbioses with other seagrasses and saltmarsh plants. Just like N2-fixing microorganisms might have aided the colonization of nitrogen-poor soils by early land plants6, the ancestors of Ca. C. neptuna and its relatives probably enabled flowering plants to invade nitrogen-poor marine habitats, where they formed extremely efficient blue carbon ecosystems7.
Asunto(s)
Alismatales/microbiología , Organismos Acuáticos/metabolismo , Bacterias/metabolismo , Fijación del Nitrógeno , Nitrógeno/metabolismo , Simbiosis , Alismatales/metabolismo , Aminoácidos/metabolismo , Amoníaco/metabolismo , Organismos Acuáticos/microbiología , Ecosistema , Endófitos/metabolismo , Mar Mediterráneo , Hojas de la Planta/metabolismo , Raíces de Plantas/metabolismo , Raíces de Plantas/microbiologíaRESUMEN
Particular frost patterns on natural leaves had prompted Yao et al. [Y. Yao et al., Proc. Natl. Acad. Sci. U.S.A. 117, 6323-6329 (2020)] to investigate the underlying physics. Their work revealed why on corrugated surfaces ice forms on crests and dries out adjacent grooves. In the absence of frost, in contrast, grooves tend to constitute niches on a leaf where microorganisms are less limited by moisture than in other locations. Here, we show that microorganisms able to nucleate ice before it forms on crests can modify the frosting pattern to their advantage. This ability might drive in cold arid environments the association between certain microorganisms and plants.
Asunto(s)
Congelación , Hojas de la Planta , HieloRESUMEN
Plant leaves, whose remarkable ability for morphogenesis results in a wide range of petal and leaf shapes in response to environmental cues, have inspired scientific studies as well as the development of engineering structures and devices. Although some typical shape changes in plants and the driving force for such shape evolution have been extensively studied, there remain many poorly understood mechanisms, characteristics, and principles associated with the vast array of shape formation of plant leaves in nature. Here, we present a comprehensive study that combines experiment, theory, and numerical simulations of one such topic-the mechanics and mechanisms of corrugated leaf folding induced by differential shrinking in Rhapis excelsa. Through systematic measurements of the dehydration process in sectioned leaves, we identify a linear correlation between change in the leaf-folding angle and water loss. Building on experimental findings, we develop a generalized model that provides a scaling relationship for water loss in sectioned leaves. Furthermore, our study reveals that corrugated folding induced by dehydration in R. excelsa leaves is achieved by the deformation of a structural architecture-the "hinge" cells. Utilizing such connections among structure, morphology, environmental stimuli, and mechanics, we fabricate several biomimetic machines, including a humidity sensor and morphing devices capable of folding in response to dehydration. The mechanisms of corrugated folding in R. excelsa identified in this work provide a general understanding of the interactions between plant leaves and water. The actuation mechanisms identified in this study also provide insights into the rational design of soft machines.