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1.
J Integr Plant Biol ; 2024 Jun 13.
Artículo en Inglés | MEDLINE | ID: mdl-38869289

RESUMEN

Pathogens generate and secrete effector proteins to the host plant cells during pathogenesis to promote virulence and colonization. If the plant carries resistance (R) proteins that recognize pathogen effectors, effector-triggered immunity (ETI) is activated, resulting in a robust immune response and hypersensitive response (HR). The bipartite effector AvrRps4 from Pseudomonas syringae pv. pisi has been well studied in terms of avirulence function. In planta, AvrRps4 is processed into two parts. The C-terminal fragment of AvrRps4 (AvrRps4C) induces HR in turnip and is recognized by the paired resistance proteins AtRRS1/AtRPS4 in Arabidopsis. Here, we show that AvrRps4C targets a group of Arabidopsis WRKY, including WRKY46, WRKY53, WRKY54, and WRKY70, to induce its virulence function. Indeed, AvrRps4C suppresses the general binding and transcriptional activities of immune-positive regulator WRKY54 and WRKY54-mediated resistance. AvrRps4C interferes with WRKY54's binding activity to target gene SARD1 in vitro, suggesting WRKY54 is sequestered from the SARD1 promoter by AvrRps4C. Through the interaction of AvrRps4C with four WRKYs, AvrRps4 enhances the formation of homo-/heterotypic complexes of four WRKYs and sequesters them in the cytoplasm, thus inhibiting their function in plant immunity. Together, our results provide a detailed virulence mechanism of AvrRps4 through its C-terminus.

2.
New Phytol ; 239(4): 1203-1211, 2023 08.
Artículo en Inglés | MEDLINE | ID: mdl-37322620

RESUMEN

Plants have developed multilayered defense strategies to adapt and acclimate to the kaleidoscopic environmental changes that rapidly produce reactive oxygen species (ROS) and induce redox changes. Thiol-based redox sensors containing the redox-sensitive cysteine residues act as the central machinery in plant defense signaling. Here, we review recent research on thiol-based redox sensors in plants, which perceive the changes in intracellular H2 O2 levels and activate specific downstream defense signaling. The review mainly focuses on the molecular mechanism of how the thiol sensors recognize internal/external stresses and respond to them by demonstrating several instances, such as cold-, drought-, salinity-, and pathogen-resistant signaling pathways. Also, we introduce another novel complex system of thiol-based redox sensors operating through the liquid-liquid phase separation.


Asunto(s)
Plantas , Compuestos de Sulfhidrilo , Compuestos de Sulfhidrilo/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Oxidación-Reducción , Plantas/metabolismo , Transducción de Señal
3.
Biochem Biophys Res Commun ; 568: 124-130, 2021 09 03.
Artículo en Inglés | MEDLINE | ID: mdl-34217011

RESUMEN

Many thioredoxin-h (Trx-h) proteins, cytosolic isotypes of Trxs, have been functionally characterized in plants; however, the physiological function of Arabidopsis Trx-h2, which harbors two active site cysteine (Cys) residues and an N-terminal extension peptide containing a fatty acid acylation site, remains unclear. In this study, we investigated the physiological function of Trx-h2 by performing several abiotic stress treatments using trx-h1-3 knockout mutant lines, and found that the reductase function of Trx-h2 is critical for cold resistance in Arabidopsis. Plants overexpressing Trx-h2 in the trx-h2 mutant background (Trx-h2OE/trx-h2) showed strong cold tolerant phenotypes compared with Col-0 (wild type) and trx-h2 mutant plants. By contrast, Trx-h2(C/S)OE/trx-h2 plants expressing a variant Trx-h2 protein, in which both active site Cys residues were substituted by serine (Ser) residues, showed high cold sensitivity, similar to trx-h2 plants. Moreover, cold-responsive (COR) genes were highly up-regulated in Trx-h2OE/trx-h2 plants but not in trx-h2 and Trx-h2(C/S)OE/trx-h2 plants under cold conditions. These results explicitly suggest that the cytosolic Trx-h2 protein relays the external cold stress signal to downstream cold defense signaling cascades through its protein disulfide reductase function.


Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/fisiología , Tiorredoxina h/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Respuesta al Choque por Frío , Regulación de la Expresión Génica de las Plantas , Oxidación-Reducción , Tiorredoxina h/genética
4.
Plant Physiol Biochem ; 206: 108219, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38048703

RESUMEN

The Arabidopsis quiescin sulfhydryl oxidase 1 (QSOX1) thiol-based redox sensor has been identified as a negative regulator of plant immunity. Here, we have found that small molecular weight proteins of QSOX1 were converted to high molecular weight (HMW) complexes upon exposure to heat stress and that this was accompanied by a switch in QSOX1 function from a thiol-reductase to a molecular chaperone. Plant treatment with S-nitrosoglutathione (GSNO), which causes nitrosylation of cysteine residues (S-nitrosylation), but not with H2O2, induced HMW QSOX1 complexes. Thus, functional switching of QSOX1 is induced by GSNO treatment. Accordingly, simultaneous treatment of plants with heat shock and GSNO led to a significant increase in QSOX1 chaperone activity by increasing its oligomerization. Consequently, transgenic Arabidopsis overexpressing QSOX1 (QSOX1OE) showed strong resistance to heat shock, whereas qsox1 knockout plants exhibited high sensitivity to heat stress. Plant treatment with GSNO under heat stress conditions increased their resistance to heat shock. We conclude that S-nitrosylation allows the thiol-based redox sensor, QSOX1, to respond to various external stresses in multiple ways.


Asunto(s)
Arabidopsis , Arabidopsis/metabolismo , Respuesta al Choque Térmico , Peróxido de Hidrógeno/metabolismo , Chaperonas Moleculares/metabolismo , Óxido Nítrico/metabolismo , Oxidación-Reducción , Compuestos de Sulfhidrilo/metabolismo
5.
Curr Dev Nutr ; 8(6): 103772, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38948109

RESUMEN

Healthy dietary practices are highly influenced by social norms, the widely-held expectations about the behaviors that are appropriate or typical within a given group. However, many nutrition programs designed to reduce women's undernutrition in low- and middle-income countries do not address the influence of social and gender norms in their interventions, and therefore, there is limited information about how norms-responsive interventions have been designed and implemented. The objective of this scoping review was to identify and describe social and behavioral change interventions designed to improve women's dietary practices and nutritional intake that integrate the influence of social and gender norms. We systematically searched 4 databases (Scopus, Web of Science, PubMed, and CINAHL) for peer-reviewed articles describing design, implementation, and/or assessment of nutrition interventions in low- or middle-income countries. Results are reported following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Our review identified 27 articles from 25 projects or research studies that addressed social or gender norms related to women's dietary practices. The majority focused on the pregnancy and lactation periods, and a few aimed to reach all women of reproductive age. Interventions most often endeavored to shift norms through multiple activities, channels, and platforms, aiming to reach not only the primary participants but also influencers and reference groups. Intervention approaches ranged from home visits and support groups to engage influential family members to community-level outreach with opinion leaders such as religious leaders, health care workers, and peer change agents. Most interventions were delivered through the health sector or were community-based, with some nutrition-sensitive agriculture interventions. There is increasing, although still limited, integration of social and gender norms perspectives in the design, implementation, and assessment of interventions to improve women's diets. This comprehensive review summarizes influential norms and intervention approaches, an important step toward enhancing the effectiveness of social and behavioral change interventions by addressing nutrition-relevant norms. This study was registered at Open Science Framework as JSBF7.

6.
FEBS Lett ; 596(15): 1871-1880, 2022 08.
Artículo en Inglés | MEDLINE | ID: mdl-35644867

RESUMEN

Environmental stresses restrict plant growth and development and decrease crop yield. The circadian clock is associated with the ability of a plant to adapt to daily environmental fluctuations and the production and consumption of energy. Here, we investigated the role of Arabidopsis Universal Stress Protein (USP; At3g53990) in the circadian regulation of nuclear clock genes. The Arabidopsis usp knockout mutant line exhibited critically diminished circadian amplitude of the central oscillator CIRCADIAN CLOCK ASSOCIATED 1 (CCA1) but enhanced the amplitude of TIMING OF CAB EXPRESSION 1 (TOC1). However, the expression of USP under the control of its own promoter restored the circadian timing of both genes, suggesting that USP regulates the circadian rhythm of Arabidopsis central clock genes, CCA1 and TOC1.


Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Relojes Circadianos , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Relojes Circadianos/genética , Ritmo Circadiano/genética , Regulación de la Expresión Génica de las Plantas , Proteínas de Choque Térmico/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismo
8.
Antioxidants (Basel) ; 10(8)2021 Aug 13.
Artículo en Inglés | MEDLINE | ID: mdl-34439534

RESUMEN

In Arabidopsis, the cytosolic redox protein thioredoxin h2 (Trx-h2) is anchored to the cytoplasmic endomembrane through the myristoylated second glycine residue (Gly2). However, under cold stress, the cytosolic Trx-h2 is rapidly translocated to the nucleus, where it interacts with and reduces the cold-responsive C-repeat-binding factors (CBFs), thus activating cold-responsive (COR) genes. In this study, we investigated the significance of fatty acid modification of Trx-h2 under cold conditions by generating transgenic Arabidopsis lines in the trx-h2 mutant background, overexpressing Trx-h2 (Trx-h2OE/trx-h2) and its point mutation variant Trx-h2(G/A) [Trx-h2(G/A)OE/trx-h2], in which the Gly2 was replaced by alanine (Ala). Due to the lack of Gly2, Trx-h2(G/A) was incapable of myristoylation, and a part of Trx-h2(G/A) localized to the nucleus even under warm temperature. As no time is spent on the demyristoylation and subsequent nuclear translocation of Trx-h2(G/A) under a cold snap, the ability of Trx-h2(G/A) to protect plants from cold stress was greater than that of Trx-h2. Additionally, COR genes were up-regulated earlier in Trx-h2(G/A)2OE/trx-h2 plants than in Trx-h2OE/trx-h2 plants under cold stress. Consequently, Trx-h2(G/A)2OE/trx-h2 plants showed greater cold tolerance than Col-0 (wild type) and Trx-h2OE/trx-h2 plants. Overall, our results clearly demonstrate the significance of the demyristoylation of Trx-h2 in enhancing plant cold/freezing tolerance.

9.
Front Plant Sci ; 10: 750, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31231414

RESUMEN

Since the original discovery of a Universal Stress Protein (USP) in Escherichia coli, a number of USPs have been identified from diverse sources including archaea, bacteria, plants, and metazoans. As their name implies, these proteins participate in a broad range of cellular responses to biotic and abiotic stresses. Their physiological functions are associated with ion scavenging, hypoxia responses, cellular mobility, and regulation of cell growth and development. Consistent with their roles in resistance to multiple stresses, USPs show a wide range of structural diversity that results from the diverse range of other functional motifs fused with the USP domain. As well as providing structural diversity, these catalytic motifs are responsible for the diverse biochemical properties of USPs and enable them to act in a number of cellular signaling transducers and metabolic regulators. Despite the importance of USP function in many organisms, the molecular mechanisms by which USPs protect cells and provide stress resistance remain largely unknown. This review addresses the diverse roles of USPs in plants and how the proteins enable plants to resist against multiple stresses in ever-changing environment. Bioinformatic tools used for the collection of a set of USPs from various plant species provide more than 2,100 USPs and their functional diversity in plant physiology. Data from previous studies are used to understand how the biochemical activity of plant USPs modulates biotic and abiotic stress signaling. As USPs interact with the redox protein, thioredoxin, in Arabidopsis and reactive oxygen species (ROS) regulates the activity of USPs, the involvement of USPs in redox-mediated defense signaling is also considered. Finally, this review discusses the biotechnological application of USPs in an agricultural context by considering the development of novel stress-resistant crops through manipulating the expression of USP genes.

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