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1.
Plant Physiol ; 2024 Sep 16.
Artículo en Inglés | MEDLINE | ID: mdl-39283986

RESUMEN

In Arabidopsis (Arabidopsis thaliana (L.) Heynh), exposure to volatile compounds (VCs) emitted by Penicillium aurantiogriseum promotes root hair (RH) proliferation and hyper-elongation through mechanisms involving ethylene, auxin and photosynthesis signaling. In addition, this treatment enhances the levels of the small signalling peptide RAPID ALKALINIZATION FACTOR 22 (RALF22). Here we used genetics to address the role of RALF22 in fungal VC-promoted RH growth and to identify the bioactive fungal VC. We found that RHs of ralf22 and feronia (fer-4) plants impaired in the expression of RALF22 and its receptor FERONIA, respectively, responded weakly to fungal VCs. Unlike in WT roots, fungal VC exposure did not enhance RALF22 transcript levels in roots of fer-4 and ethylene- and auxin- insensitive mutants. In ralf22 and fer-4 roots, this treatment did not enhance the levels of ERS2 transcripts encoding one member of the ethylene receptor family and those of some RH-related genes. RHs of ers2-1 and the rsl2rsl4 double mutants impaired in the expression of ERS2 and the ethylene- and auxin-responsive ROOT HAIR DEFECTIVE 6-LIKE 2 and 4 transcription factors, respectively, weakly responded to fungal VCs. Moreover, roots of plants defective in photosynthetic responsiveness to VCs exhibited weak RALF22 expression and RH growth responses to fungal VCs. VCs of ΔefeA strains of P. aurantiogriseum cultures impaired in ethylene synthesis weakly promoted RH proliferation and elongation in exposed plants. We conclude that RALF22 simultaneously functions as a transcriptionally regulated signaling molecule that participates in the ethylene, auxin and photosynthesis signaling-mediated RH growth response to fungal ethylene emissions and regulation of ethylene perception in RHs.

2.
EMBO J ; 39(9): e103894, 2020 05 04.
Artículo en Inglés | MEDLINE | ID: mdl-32187732

RESUMEN

Production of reactive oxygen species (ROS) by NADPH oxidases (NOXs) impacts many processes in animals and plants, and many plant receptor pathways involve rapid, NOX-dependent increases of ROS. Yet, their general reactivity has made it challenging to pinpoint the precise role and immediate molecular action of ROS. A well-understood ROS action in plants is to provide the co-substrate for lignin peroxidases in the cell wall. Lignin can be deposited with exquisite spatial control, but the underlying mechanisms have remained elusive. Here, we establish a kinase signaling relay that exerts direct, spatial control over ROS production and lignification within the cell wall. We show that polar localization of a single kinase component is crucial for pathway function. Our data indicate that an intersection of more broadly localized components allows for micrometer-scale precision of lignification and that this system is triggered through initiation of ROS production as a critical peroxidase co-substrate.


Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Lignina/metabolismo , Proteínas Quinasas/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Regulación de la Expresión Génica de las Plantas , NADPH Oxidasas/metabolismo , Peroxidasas/metabolismo , Raíces de Plantas/metabolismo
3.
Proc Natl Acad Sci U S A ; 117(5): 2693-2703, 2020 02 04.
Artículo en Inglés | MEDLINE | ID: mdl-31964818

RESUMEN

Plants use leucine-rich repeat receptor kinases (LRR-RKs) to sense sequence diverse peptide hormones at the cell surface. A 3.0-Å crystal structure of the LRR-RK GSO1/SGN3 regulating Casparian strip formation in the endodermis reveals a large spiral-shaped ectodomain. The domain provides a binding platform for 21 amino acid CIF peptide ligands, which are tyrosine sulfated by the tyrosylprotein sulfotransferase TPST/SGN2. GSO1/SGN3 harbors a binding pocket for sulfotyrosine and makes extended backbone interactions with CIF2. Quantitative biochemical comparisons reveal that GSO1/SGN3-CIF2 represents one of the strongest receptor-ligand pairs known in plants. Multiple missense mutations are required to block CIF2 binding in vitro and GSO1/SGN3 function in vivo. Using structure-guided sequence analysis we uncover previously uncharacterized CIF peptides conserved among higher plants. Quantitative binding assays with known and novel CIFs suggest that the homologous LRR-RKs GSO1/SGN3 and GSO2 have evolved unique peptide binding properties to control different developmental processes. A quantitative biochemical interaction screen, a CIF peptide antagonist and genetic analyses together implicate SERK proteins as essential coreceptor kinases required for GSO1/SGN3 and GSO2 receptor activation. Our work provides a mechanistic framework for the recognition of sequence-divergent peptide hormones in plants.


Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Péptidos/metabolismo , Proteínas Quinasas/metabolismo , Secuencia de Aminoácidos , Arabidopsis/química , Arabidopsis/enzimología , Arabidopsis/genética , Proteínas de Arabidopsis/química , Proteínas de Arabidopsis/genética , Cinética , Ligandos , Péptidos/química , Reguladores del Crecimiento de las Plantas/química , Reguladores del Crecimiento de las Plantas/metabolismo , Unión Proteica , Proteínas Quinasas/química , Proteínas Quinasas/genética
4.
Curr Biol ; 28(15): 2452-2458.e4, 2018 08 06.
Artículo en Inglés | MEDLINE | ID: mdl-30057301

RESUMEN

The growth of plants, like that of other walled organisms, depends on the ability of the cell wall to yield without losing its integrity. In this context, plant cells can sense the perturbation of their walls and trigger adaptive modifications in cell wall polymer interactions. Catharanthus roseus receptor-like kinase 1-like (CrRLK1L) THESEUS1 (THE1) was previously shown in Arabidopsis to trigger growth inhibition and defense responses upon perturbation of the cell wall, but so far, neither the ligand nor the role of the receptor in normal development was known. Here, we report that THE1 is a receptor for the peptide rapid alkalinization factor (RALF) 34 and that this signaling module has a role in the fine-tuning of lateral root initiation. We also show that RALF34-THE1 signaling depends, at least for some responses, on FERONIA (FER), another RALF receptor involved in a variety of processes, including immune signaling, mechanosensing, and reproduction [1]. Together, the results show that RALF34 and THE1 are part of a signaling network that integrates information on the integrity of the cell wall with the coordination of normal morphogenesis.


Asunto(s)
Proteínas de Arabidopsis/genética , Arabidopsis/genética , Hormonas Peptídicas/genética , Raíces de Plantas/crecimiento & desarrollo , Proteínas Quinasas/genética , Receptores de Superficie Celular/genética , Transducción de Señal , Arabidopsis/crecimiento & desarrollo , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Pared Celular/metabolismo , Hormonas Peptídicas/metabolismo , Raíces de Plantas/genética , Proteínas Quinasas/metabolismo , Receptores de Superficie Celular/metabolismo
6.
Curr Opin Plant Biol ; 39: 136-143, 2017 10.
Artículo en Inglés | MEDLINE | ID: mdl-28750257

RESUMEN

Plant roots acquire nutrients from the soil and transport them upwards to the aerial parts. To reach the central vasculature of the root, water and nutrients radially cross all external cell layers. The endodermis surrounds the vascular tissues and forms diffusion barriers. It thereby compartmentalizes the root and allows control of nutrient transport from the soil to the vasculature, as well as preventing backflow of nutrients from the stele. To achieve this role, endodermal cells undergo two specialized differentiations states consisting of deposition of two impermeable polymers in the cell wall: lignin, forming the Casparian strips, and suberin lamellae. Recent publications showed that endodermal barrier formation is not a hard-wired, irreversible process. Synthesis and degradation of suberin lamellae is highly regulated by plant hormones in response to nutrient stresses. Moreover, Casparian strip continuity seems to be constantly checked by two small peptides produced in the vasculature that diffuse into the apoplastic space in order to test endodermal barrier integrity. This review discusses the recent understanding of endodermal barrier surveillance and plasticity and its role in plant nutrition.


Asunto(s)
Raíces de Plantas/metabolismo , Haz Vascular de Plantas/metabolismo
7.
Science ; 355(6322): 280-284, 2017 01 20.
Artículo en Inglés | MEDLINE | ID: mdl-28104888

RESUMEN

The root endodermis forms its extracellular diffusion barrier by developing ringlike impregnations called Casparian strips. A factor responsible for their establishment is the SCHENGEN3/GASSHO1 (SGN3/GSO1) receptor-like kinase. Its loss of function causes discontinuous Casparian strips. SGN3 also mediates endodermal overlignification of other Casparian strip mutants. Yet, without ligand, SGN3 function remained elusive. Here we report that schengen2 (sgn2) is defective in an enzyme sulfating peptide ligands. On the basis of this observation, we identified two stele-expressed peptides (CASPARIAN STRIP INTEGRITY FACTORS, CIF1/2) that complement sgn2 at nanomolar concentrations and induce Casparian strip mislocalization as well as overlignification-all of which depend on SGN3. Direct peptide binding to recombinant SGN3 identifies these peptides as SGN3 ligands. We speculate that CIF1/2-SGN3 is part of a barrier surveillance system, evolved to guarantee effective sealing of the supracellular Casparian strip network.


Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Raíces de Plantas/metabolismo , Proteínas Quinasas/metabolismo , Sulfotransferasas/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Difusión , Ligandos , Péptidos/metabolismo , Raíces de Plantas/genética , Unión Proteica , Proteínas Quinasas/genética , Sulfotransferasas/genética
8.
Nat Plants ; 2: 16113, 2016 07 25.
Artículo en Inglés | MEDLINE | ID: mdl-27455051

RESUMEN

Casparian strips are precisely localized and aligned ring-like cell wall modifications in the root of all higher plants. They set up an extracellular diffusion barrier analogous to animal tight junctions, and are crucial for maintaining the homeostatic capacity of plant roots. Casparian strips become localized because of the formation of a highly stable plasma membrane domain, consisting of a family of small transmembrane proteins called Casparian strip membrane domain proteins (CASPs). Here we report a large-scale forward genetic screen directly visualizing endodermal barrier function, which allowed us to identify factors required for the formation and integrity of Casparian strips. We present the identification and characterization of one of the mutants, schengen1 (sgn1), a receptor-like cytoplasmic kinase that we show localizes in a strictly polar fashion to the outer plasma membrane of endodermal cells and is required for the positioning and correct formation of the centrally located CASP domain.


Asunto(s)
Proteínas de Arabidopsis/genética , Arabidopsis/genética , Membrana Celular/metabolismo , Pared Celular/metabolismo , Proteínas de la Membrana/genética , Proteínas de Arabidopsis/metabolismo , Difusión , Proteínas de la Membrana/metabolismo
9.
Biotechnol J ; 10(3): 490-500, 2015 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-25143316

RESUMEN

Increasing L-ascorbic acid (AsA, vitamin C) content in fruits is a common goal in current breeding programs due to its beneficial effect on human health. Attempts to increase AsA content by genetic engineering have resulted in variable success likely due to AsA's complex regulation. Here, we report the effect of ectopically expressing in tomato the D-galacturonate reductase (FaGalUR) gene from strawberry, involved in AsA biosynthesis, either under the control of the constitutive 35S or the tomato fruit-specific polygalucturonase (PG) promoters. Although transgenic lines showed a moderate increase on AsA content, complex changes in metabolites were found in transgenic fruits. Metabolomic analyses of ripe fruits identified a decrease in citrate, glutamate, asparagine, glucose, and fructose, accompanied by an increase of sucrose, galactinol, and chlorogenic acid. Significant metabolic changes also occurred in leaves of 35S-FaGalUR lines, which showed higher non-photochemical fluorescence quenching (NPQ), indicative of a higher constitutive photo-protective capacity. Overall, overexpression of FaGalUR increased total antioxidant capacity in fruits and the results suggest a tight control of AsA content, probably linked to a complex regulation of cellular redox state and metabolic adjustment.


Asunto(s)
Antioxidantes/metabolismo , Expresión Génica Ectópica , Fragaria/enzimología , Oxidorreductasas de Alcohol Dependientes de NAD (+) y NADP (+)/metabolismo , Plantas Modificadas Genéticamente/metabolismo , Solanum lycopersicum/genética , Ácido Ascórbico/metabolismo , Frutas/metabolismo , Regulación de la Expresión Génica de las Plantas , Genes de Plantas , Humanos , Solanum lycopersicum/metabolismo , Metabolómica/métodos , Oxidorreductasas de Alcohol Dependientes de NAD (+) y NADP (+)/genética , Hojas de la Planta/metabolismo , Regiones Promotoras Genéticas
10.
Plant Cell ; 25(2): 728-43, 2013 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-23404890

RESUMEN

The 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR) enzyme catalyzes the major rate-limiting step of the mevalonic acid (MVA) pathway from which sterols and other isoprenoids are synthesized. In contrast with our extensive knowledge of the regulation of HMGR in yeast and animals, little is known about this process in plants. To identify regulatory components of the MVA pathway in plants, we performed a genetic screen for second-site suppressor mutations of the Arabidopsis thaliana highly drought-sensitive drought hypersensitive2 (dry2) mutant that shows decreased squalene epoxidase activity. We show that mutations in SUPPRESSOR OF DRY2 DEFECTS1 (SUD1) gene recover most developmental defects in dry2 through changes in HMGR activity. SUD1 encodes a putative E3 ubiquitin ligase that shows sequence and structural similarity to yeast Degradation of α factor (Doα10) and human TEB4, components of the endoplasmic reticulum-associated degradation C (ERAD-C) pathway. While in yeast and animals, the alternative ERAD-L/ERAD-M pathway regulates HMGR activity by controlling protein stability, SUD1 regulates HMGR activity without apparent changes in protein content. These results highlight similarities, as well as important mechanistic differences, among the components involved in HMGR regulation in plants, yeast, and animals.


Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Hidroximetilglutaril-CoA Reductasas/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Humanos , Proteínas de la Membrana/genética , Ácido Mevalónico/metabolismo , Mutación , Fenotipo , Raíces de Plantas/genética , Raíces de Plantas/crecimiento & desarrollo , Raíces de Plantas/metabolismo , Brotes de la Planta/genética , Brotes de la Planta/metabolismo , Plantas Modificadas Genéticamente , Proteínas de Saccharomyces cerevisiae/genética , Homología de Secuencia de Aminoácido , Esteroles/metabolismo , Ubiquitina-Proteína Ligasas/genética
11.
Plant Physiol ; 158(3): 1252-66, 2012 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-22232384

RESUMEN

TETRATRICOPEPTIDE THIOREDOXIN-LIKE (TTL) proteins are characterized by the presence of six tetratricopeptide repeats in conserved positions and a carboxyl-terminal region known as the thioredoxin-like domain with homology to thioredoxins. In Arabidopsis (Arabidopsis thaliana), the TTL gene family is composed by four members, and the founder member, TTL1, is required for osmotic stress tolerance. Analysis of sequenced genomes indicates that TTL genes are specific to land plants. In this study, we report the expression profiles of Arabidopsis TTL genes using data mining and promoter-reporter ß-glucuronidase fusions. Our results show that TTL1, TTL3, and TTL4 display ubiquitous expression in normal growing conditions but differential expression patterns in response to osmotic and NaCl stresses. TTL2 shows a very different expression pattern, being specific to pollen grains. Consistent with the expression data, ttl1, ttl3, and ttl4 mutants show reduced root growth under osmotic stress, and the analysis of double and triple mutants indicates that TTL1, TTL3, and TTL4 have partially overlapping yet specific functions in abiotic stress tolerance while TTL2 is involved in male gametophytic transmission.


Asunto(s)
Adaptación Fisiológica , Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Estrés Fisiológico , Arabidopsis/efectos de los fármacos , Arabidopsis/metabolismo , Arabidopsis/fisiología , Proteínas de Arabidopsis/clasificación , Proteínas de Arabidopsis/genética , Biología Computacional , Minería de Datos , Perfilación de la Expresión Génica , Regulación de la Expresión Génica de las Plantas , Genes de Plantas , Genes Reporteros , Glucuronidasa/genética , Glucuronidasa/metabolismo , Familia de Multigenes , Mutación , Filogenia , Raíces de Plantas/genética , Raíces de Plantas/metabolismo , Raíces de Plantas/fisiología , Plantas Modificadas Genéticamente/efectos de los fármacos , Plantas Modificadas Genéticamente/genética , Plantas Modificadas Genéticamente/metabolismo , Plantas Modificadas Genéticamente/fisiología , Polen/genética , Polen/metabolismo , Polen/fisiología , Regiones Promotoras Genéticas , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Cloruro de Sodio/farmacología
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