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1.
Cell ; 177(4): 942-956.e14, 2019 05 02.
Artigo em Inglês | MEDLINE | ID: mdl-30955889

RESUMO

Plants are sessile and have to cope with environmentally induced damage through modification of growth and defense pathways. How tissue regeneration is triggered in such responses and whether this involves stem cell activation is an open question. The stress hormone jasmonate (JA) plays well-established roles in wounding and defense responses. JA also affects growth, which is hitherto interpreted as a trade-off between growth and defense. Here, we describe a molecular network triggered by wound-induced JA that promotes stem cell activation and regeneration. JA regulates organizer cell activity in the root stem cell niche through the RBR-SCR network and stress response protein ERF115. Moreover, JA-induced ERF109 transcription stimulates CYCD6;1 expression, functions upstream of ERF115, and promotes regeneration. Soil penetration and response to nematode herbivory induce and require this JA-mediated regeneration response. Therefore, the JA tissue damage response pathway induces stem cell activation and regeneration and activates growth after environmental stress.


Assuntos
Ciclopentanos/metabolismo , Oxilipinas/metabolismo , Raízes de Plantas/metabolismo , Células-Tronco/metabolismo , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Ciclinas/metabolismo , Regulação da Expressão Gênica de Plantas/genética , Herbivoria , Ácidos Indolacéticos/metabolismo , Regeneração/fisiologia , Transdução de Sinais/fisiologia , Estresse Fisiológico , Fatores de Transcrição/metabolismo
2.
Cell ; 176(4): 702-715.e14, 2019 02 07.
Artigo em Inglês | MEDLINE | ID: mdl-30661758

RESUMO

Voltage-gated sodium (Nav) channels are targets of disease mutations, toxins, and therapeutic drugs. Despite recent advances, the structural basis of voltage sensing, electromechanical coupling, and toxin modulation remains ill-defined. Protoxin-II (ProTx2) from the Peruvian green velvet tarantula is an inhibitor cystine-knot peptide and selective antagonist of the human Nav1.7 channel. Here, we visualize ProTx2 in complex with voltage-sensor domain II (VSD2) from Nav1.7 using X-ray crystallography and cryoelectron microscopy. Membrane partitioning orients ProTx2 for unfettered access to VSD2, where ProTx2 interrogates distinct features of the Nav1.7 receptor site. ProTx2 positions two basic residues into the extracellular vestibule to antagonize S4 gating-charge movement through an electrostatic mechanism. ProTx2 has trapped activated and deactivated states of VSD2, revealing a remarkable ∼10 Å translation of the S4 helix, providing a structural framework for activation gating in voltage-gated ion channels. Finally, our results deliver key templates to design selective Nav channel antagonists.


Assuntos
Canal de Sódio Disparado por Voltagem NAV1.7/metabolismo , Canal de Sódio Disparado por Voltagem NAV1.7/ultraestrutura , Peptídeos/metabolismo , Venenos de Aranha/metabolismo , Sequência de Aminoácidos , Animais , Sítios de Ligação , Células CHO , Cricetulus , Microscopia Crioeletrônica/métodos , Cristalografia por Raios X/métodos , Células HEK293 , Humanos , Ativação do Canal Iônico , Peptídeos/toxicidade , Domínios Proteicos , Venenos de Aranha/toxicidade , Aranhas , Bloqueadores do Canal de Sódio Disparado por Voltagem , Canais de Sódio Disparados por Voltagem/metabolismo
3.
Proc Natl Acad Sci U S A ; 120(31): e2205552120, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37487090

RESUMO

We consider the Lorenz equations, a system of three-dimensional ordinary differential equations modeling atmospheric convection. These equations are chaotic and hard to study even numerically, and so a simpler "geometric model" has been introduced in the seventies. One of the classical problems in dynamical systems is to relate the original equations to the geometric model. This has been achieved numerically by Tucker for the classical parameter values and remains open for general values. In this paper, we establish analytically a relation to the geometric model for a different set of parameter values that we prove must exist. This is facilitated by finding a way to apply topological tools developed for the study of surface dynamics to the more intricate case of three-dimensional flows.

4.
Proc Natl Acad Sci U S A ; 120(29): e2304612120, 2023 07 18.
Artigo em Inglês | MEDLINE | ID: mdl-37428936

RESUMO

Root-knot nematodes (Meloidogyne spp.) are highly evolved obligate parasites threatening global food security. These parasites have a remarkable ability to establish elaborate feeding sites in roots, which are their only source of nutrients throughout their life cycle. A wide range of nematode effectors have been implicated in modulation of host pathways for defense suppression and/or feeding site development. Plants produce a diverse array of peptide hormones including PLANT PEPTIDE CONTAINING SULFATED TYROSINE (PSY)-family peptides, which promote root growth via cell expansion and proliferation. A sulfated PSY-like peptide RaxX (required for activation of XA21 mediated immunity X) produced by the biotrophic bacterial pathogen (Xanthomonas oryzae pv. oryzae) has been previously shown to contribute to bacterial virulence. Here, we report the identification of genes from root-knot nematodes predicted to encode PSY-like peptides (MigPSYs) with high sequence similarity to both bacterial RaxX and plant PSYs. Synthetic sulfated peptides corresponding to predicted MigPSYs stimulate root growth in Arabidopsis. MigPSY transcript levels are highest early in the infection cycle. Downregulation of MigPSY gene expression reduces root galling and egg production, suggesting that the MigPSYs serve as nematode virulence factors. Together, these results indicate that nematodes and bacteria exploit similar sulfated peptides to hijack plant developmental signaling pathways to facilitate parasitism.


Assuntos
Arabidopsis , Nematoides , Parasitos , Tylenchoidea , Animais , Plantas , Peptídeos , Transdução de Sinais , Tirosina , Doenças das Plantas/microbiologia , Tylenchoidea/genética , Raízes de Plantas
5.
Proc Natl Acad Sci U S A ; 120(1): e2218630120, 2023 01 03.
Artigo em Inglês | MEDLINE | ID: mdl-36574673

RESUMO

A family of leucine-rich-repeat-containing G-protein-coupled receptors (LGRs) mediate diverse physiological responses when complexed with their cognate ligands. LGRs are present in all metazoan animals. In humans, the LGR ligands include glycoprotein hormones (GPHs) chorionic gonadotropin (hCG), luteinizing hormone, follicle-stimulating hormone (hFSH), and thyroid-stimulating hormone (hTSH). These hormones are αß heterodimers of cystine-knot protein chains. LGRs and their ligand chains have coevolved. Ancestral hormone homologs, present in both bilaterian animals and chordates, are identified as α2ß5. We have used single-wavelength anomalous diffraction and molecular replacement to determine structures of the α2ß5 hormone from Caenorhabditis elegans (Ceα2ß5). Ceα2ß5 is unglycosylated, as are many other α2ß5 hormones. Both Hsα2ß5, the human homolog of Ceα2ß5, and hTSH activate the same receptor (hTSHR). Despite having little sequence similarity to vertebrate GPHs, apart from the cysteine patterns from core disulfide bridges, Ceα2ß5 is generally similar in structure to these counterparts; however, its α2 and ß5 subunits are more symmetric as compared with α and ß of hCG and hFSH. This quasisymmetry suggests a hypothetical homodimeric antecedent of the α2ß5 and αß heterodimers. Known structures together with AlphaFold models from the sequences for other LGR ligands provide representatives for the molecular evolution of LGR ligands from early metazoans through the present-day GPHs. The experimental Ceα2ß5 structure validates its AlphaFold model, and thus also that for Hsα2ß5; and interfacial characteristics in a model for the Hsα2ß5:hTSHR complex are similar to those found in an experimental hTSH:hTSHR structure.


Assuntos
Caenorhabditis elegans , Glicoproteínas , Hormônios , Receptores Acoplados a Proteínas G , Animais , Sequência de Aminoácidos , Caenorhabditis elegans/genética , Caenorhabditis elegans/metabolismo , Ligantes , Receptores Acoplados a Proteínas G/genética
6.
J Biol Chem ; 300(4): 107125, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38432638

RESUMO

Cyclotides are plant-derived peptides characterized by a head-to-tail cyclic backbone and a cystine knot motif comprised of three disulfide bonds. Formation of this motif via in vitro oxidative folding can be challenging and can result in misfolded isomers with nonnative disulfide connectivities. Here, we investigated the effect of ß-turn nucleation on cyclotide oxidative folding. Two types of ß-turn mimics were grafted into kalata B1, individually replacing each of the four ß-turns in the folded cyclotide. Insertion of d-Pro-Gly into loop 5 was beneficial to the folding of both cyclic kB1 and a linear form of the peptide. The linear grafted analog folded four-times faster in aqueous conditions than cyclic kB1 in optimized conditions. Additionally, the cyclic analogue folded without the need for redox agents by transitioning through a native-like intermediate that was on-pathway to product formation. Kalata B1 is from the Möbius subfamily of cyclotides. Grafting d-Pro-Gly into loop 5 of cyclotides from two other subfamilies also had a beneficial effect on folding. Our findings demonstrate the importance of a ß-turn nucleation site for cyclotide oxidative folding, which could be adopted as a chemical strategy to improve the in vitro folding of diverse cystine-rich peptides.


Assuntos
Ciclotídeos , Oxirredução , Dobramento de Proteína , Ciclotídeos/química , Proteínas de Plantas/química , Sequência de Aminoácidos
7.
J Biol Chem ; 300(4): 107203, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38508311

RESUMO

We are entering an exciting time in structural biology where artificial intelligence can be used to predict protein structures with greater accuracy than ever before. Extending this level of accuracy to the predictions of disulfide-rich peptide structures is likely to be more challenging, at least in the short term, given the tight packing of cysteine residues and the numerous ways that the disulfide bonds can potentially be linked. It has been previously shown in many cases that several disulfide bond connectivities can be accommodated by a single set of NMR-derived structural data without significant violations. Disulfide-rich peptides are prevalent throughout nature, and arguably the most well-known are those present in venoms from organisms such as cone snails. Here, we have determined the first three-dimensional structure and disulfide connectivity of a U-superfamily cone snail venom peptide, TxVIIB. TxVIIB has a VI/VII cysteine framework that is generally associated with an inhibitor cystine knot (ICK) fold; however, AlphaFold predicted that the peptide adopts a mini-granulin fold with a granulin disulfide connectivity. Our experimental studies using NMR spectroscopy and orthogonal protection of cysteine residues indicate that TxVIIB indeed adopts a mini-granulin fold but with the ICK disulfide connectivity. Our findings provide structural insight into the underlying features that govern formation of the mini-granulin fold rather than the ICK fold and will provide fundamental information for prediction algorithms, as the subtle complexity of disulfide isomers may be not adequately addressed by the current prediction algorithms.


Assuntos
Conotoxinas , Animais , Sequência de Aminoácidos , Conotoxinas/química , Caramujo Conus , Cisteína/química , Dissulfetos/química , Granulinas/química , Granulinas/metabolismo , Modelos Moleculares , Ressonância Magnética Nuclear Biomolecular , Dobramento de Proteína
8.
EMBO J ; 40(1): e105393, 2021 01 04.
Artigo em Inglês | MEDLINE | ID: mdl-33155682

RESUMO

The juxtaposition of intracellular DNA segments, together with the DNA-passage activity of topoisomerase II, leads to the formation of DNA knots and interlinks, which jeopardize chromatin structure and gene expression. Recent studies in budding yeast have shown that some mechanism minimizes the knotting probability of intracellular DNA. Here, we tested whether this is achieved via the intrinsic capacity of topoisomerase II for simplifying the equilibrium topology of DNA; or whether it is mediated by SMC (structural maintenance of chromosomes) protein complexes like condensin or cohesin, whose capacity to extrude DNA loops could enforce dissolution of DNA knots by topoisomerase II. We show that the low knotting probability of DNA does not depend on the simplification capacity of topoisomerase II nor on the activities of cohesin or Smc5/6 complexes. However, inactivation of condensin increases the occurrence of DNA knots throughout the cell cycle. These results suggest an in vivo role for the DNA loop extrusion activity of condensin and may explain why condensin disruption produces a variety of alterations in interphase chromatin, in addition to persistent sister chromatid interlinks in mitotic chromatin.


Assuntos
Adenosina Trifosfatases/metabolismo , Proteínas de Ciclo Celular/metabolismo , Proteínas Cromossômicas não Histona/metabolismo , DNA Topoisomerases Tipo II/metabolismo , Proteínas de Ligação a DNA/metabolismo , DNA/metabolismo , Complexos Multiproteicos/metabolismo , Ciclo Celular/fisiologia , Cromátides/metabolismo , Cromatina/metabolismo , Saccharomyces cerevisiae/metabolismo , Coesinas
9.
Bioinformatics ; 2024 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-39037932

RESUMO

SUMMARY: Analysing protein structure similarities is an important step in protein engineering and drug discovery. Methodologies that are more advanced than simple RMSD are available but often require extensive mathematical or computational knowledge for implementation. Grouping and optimising such tools in an efficient open-source library increases accessibility and encourages the adoption of more advanced metrics. Melodia is a Python library with a complete set of components devised for describing, comparing and analysing the shape of protein structures using differential geometry of three-dimensional curves and knot theory. It can generate robust geometric descriptors for thousands of shapes in just a few minutes. Those descriptors are more sensitive to structural feature variation than RMSD deviation. Melodia also incorporates sequence structural annotation and three-dimensional visualisations. AVAILABILITY AND IMPLEMENTATION: Melodia is an open-source Python library freely available on https://github.com/rwmontalvao/Melodia_py, along with interactive Jupyter Notebook tutorials. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

10.
J Biol Chem ; 299(7): 104901, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37302550

RESUMO

Collagen superfamily of proteins is a major component of the extracellular matrix. Defects in collagens underlie the cause of nearly 40 human genetic diseases in millions of people worldwide. Pathogenesis typically involves genetic alterations of the triple helix, a hallmark structural feature that bestows exceptional mechanical resistance to tensile forces and a capacity to bind a plethora of macromolecules. Yet, there is a paramount knowledge gap in understanding the functionality of distinct sites along the triple helix. Here, we present a recombinant technique to produce triple helical fragments for functional studies. The experimental strategy utilizes the unique capacity of the NC2 heterotrimerization domain of collagen IX to drive three α-chain selection and registering the triple helix stagger. For proof of principle, we produced and characterized long triple helical fragments of collagen IV that were expressed in a mammalian system. The heterotrimeric fragments encompassed the CB3 trimeric peptide of collagen IV, which harbors the binding motifs for α1ß1 and α2ß1 integrins. Fragments were characterized and shown to have a stable triple helix, post-translational modifications, and high affinity and specific binding of integrins. The NC2 technique is a universal tool for the high-yield production of heterotrimeric fragments of collagens. Fragments are suitable for mapping functional sites, determining coding sequences of binding sites, elucidating pathogenicity and pathogenic mechanisms of genetic mutations, and production of fragments for protein replacement therapy.


Assuntos
Colágeno Tipo IV , Integrinas , Multimerização Proteica , Animais , Humanos , Sítios de Ligação , Colágeno Tipo IV/química , Colágeno Tipo IV/genética , Colágeno Tipo IV/metabolismo , Integrinas/química , Integrinas/metabolismo , Ligação Proteica , Estrutura Secundária de Proteína , Mutação , Domínios Proteicos
11.
Mol Plant Microbe Interact ; 37(3): 179-189, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37870371

RESUMO

Root-knot and cyst nematodes are two groups of plant parasitic nematodes that cause the majority of crop losses in agriculture. As a result, these nematodes are the focus of most nematode effector research. Root-knot and cyst nematode effectors are defined as secreted molecules, typically proteins, with crucial roles in nematode parasitism. There are likely hundreds of secreted effector molecules exuded through the nematode stylet into the plant. The current research has shown that nematode effectors can target a variety of host proteins and have impacts that include the suppression of plant immune responses and the manipulation of host hormone signaling. The discovery of effectors that localize to the nucleus indicates that the nematodes can directly modulate host gene expression for cellular reprogramming during feeding site formation. In addition, plant peptide mimicry by some nematode effectors highlights the sophisticated strategies the nematodes employ to manipulate host processes. Here we describe research on the interactions between nematode effectors and host proteins that will provide insights into the molecular mechanisms underpinning plant-nematode interactions. By identifying the host proteins and pathways that are targeted by root-knot and cyst nematode effectors, scientists can gain a better understanding of how nematodes establish feeding sites and subvert plant immune responses. Such information will be invaluable for future engineering of nematode-resistant crops, ultimately fostering advancements in agricultural practices and crop protection. [Formula: see text] The author(s) have dedicated the work to the public domain under the Creative Commons CC0 "No Rights Reserved" license by waiving all of his or her rights to the work worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law, 2024.


Assuntos
Cistos , Tylenchida , Tylenchoidea , Animais , Feminino , Tylenchoidea/genética , Interações Hospedeiro-Parasita/fisiologia , Transdução de Sinais , Produtos Agrícolas , Doenças das Plantas/parasitologia
12.
J Gen Virol ; 105(7)2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38975739

RESUMO

The 2020/2021 epidemic in Europe of highly pathogenic avian influenza virus (HPAIV) of subtype H5 surpassed all previously recorded European outbreaks in size, genotype constellations and reassortment frequency and continued into 2022 and 2023. The causative 2.3.4.4b viral lineage proved to be highly proficient with respect to reassortment with cocirculating low pathogenic avian influenza viruses and seems to establish an endemic status in northern Europe. A specific HPAIV reassortant of the subtype H5N3 was detected almost exclusively in red knots (Calidris canutus islandica) in December 2020. It caused systemic and rapidly fatal disease leading to a singular and self-limiting mass mortality affecting about 3500 birds in the German Wadden Sea, roughly 1 % of the entire flyway population of islandica red knots. Phylogenetic analyses revealed that the H5N3 reassortant very likely had formed in red knots and remained confined to this species. While mechanisms of virus circulation in potential reservoir species, dynamics of spill-over and reassortment events and the roles of environmental virus sources remain to be identified, the year-round infection pressure poses severe threats to endangered avian species and prompts adaptation of habitat and species conservation practices.


Assuntos
Vírus da Influenza A , Influenza Aviária , Filogenia , Vírus Reordenados , Animais , Influenza Aviária/virologia , Influenza Aviária/epidemiologia , Europa (Continente)/epidemiologia , Vírus da Influenza A/genética , Vírus da Influenza A/classificação , Vírus da Influenza A/patogenicidade , Vírus Reordenados/genética , Surtos de Doenças/veterinária , Charadriiformes/virologia , Aves/virologia
13.
Biochem Biophys Res Commun ; 720: 150086, 2024 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-38761478

RESUMO

Root-knot nematode (RKN) is one of the most damaging plant pathogen in the world. They exhibit a wide host range and cause serious crop losses. The cell wall, encasing every plant cell, plays a crucial role in defending of RKN invasion. Expansins are a group of cell wall proteins inducing cell wall loosening and extensibility. They are widely involved in the regulation of plant growth and the response to biotic and abiotic stresses. In this study, we have characterized the biological function of tobacco (Nicotiana tabacum) NtEXPA7, the homologue of Solyc08g080060.2 (SlEXPA18), of which the transcription level was significantly reduced in susceptible tomato upon RKN infection. The expression of NtEXPA7 was up-regulated after inoculation of RKNs. The NtEXPA7 protein resided in the cell wall. Overexpression of NtEXPA7 promoted the seedling growth of transgenic tobacco. Meanwhile the increased expression of NtEXPA7 was beneficial to enhance the resistance against RKNs. This study expands the understanding of biological role of expansin in coordinate plant growth and disease resistance.


Assuntos
Resistência à Doença , Regulação da Expressão Gênica de Plantas , Nicotiana , Doenças das Plantas , Proteínas de Plantas , Plantas Geneticamente Modificadas , Plântula , Nicotiana/parasitologia , Nicotiana/genética , Nicotiana/metabolismo , Animais , Plântula/parasitologia , Plântula/crescimento & desenvolvimento , Plântula/genética , Plântula/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Doenças das Plantas/parasitologia , Doenças das Plantas/genética , Resistência à Doença/genética , Plantas Geneticamente Modificadas/parasitologia , Tylenchoidea/fisiologia , Parede Celular/metabolismo , Parede Celular/parasitologia , Raízes de Plantas/parasitologia , Raízes de Plantas/metabolismo , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/genética
14.
BMC Plant Biol ; 24(1): 469, 2024 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-38811862

RESUMO

BACKGROUND: Green nanoparticles are considered to be an effective strategy for improving phytochemicals and raising productivity in soil infected by root-knot nematodes. This work aims to understand the characteristics of certain nanomaterials, including non-iron (nFe), green non-iron (GnFe), and green magnetic nanobiochar (GMnB), and the effect of adding them at 3 and 6 mg kg- 1 on phytochemicals and tomato (Solanum lycopersicum) plant growth in soils infected by root-knot nematodes. RESULTS: Spectroscopic characterization of nanomaterials showed that nFe, GnFe, and GMnB contained functional groups (e.g., Fe-O, S-H, C-H, OH, and C = C) and possessed a large surface area. Application of GMB at 6 mg kg- 1 was the most efficient treatment for increasing the phytochemicals of the tomato plant, with a rise of 123.2% in total phenolic, 194.7% in total flavonoids, 89.7% in total carbohydrate, 185.2% in total free amino acids, and 165.1% in total tannin compared to the untreated soil. Tomato plant growth and attributes increased with increasing levels of soil nano-amendment in this investigation. The addition of GnFe3 and GnFe6 increased the reduction of root galls of root-knot nematodes by 22.44% and 17.76% compared with nFe3 and nFe6, respectively. The inclusion of the examined soil nano-amendments increased phytochemicals and reduced the total number of root-knot nematodes on tomato plants at varying rates, which played a significant role in enhancing tomato growth. CONCLUSIONS: In conclusion, treating tomato plants with GnFe or GMnB can be used as a promising green nanomaterial to eliminate root-knot nematodes and increase tomato yield in sandy clay loam soil.


Assuntos
Compostos Fitoquímicos , Solanum lycopersicum , Tylenchoidea , Solanum lycopersicum/parasitologia , Solanum lycopersicum/crescimento & desenvolvimento , Animais , Compostos Fitoquímicos/química , Tylenchoidea/fisiologia , Tylenchoidea/efeitos dos fármacos , Doenças das Plantas/parasitologia , Doenças das Plantas/prevenção & controle , Nanopartículas Magnéticas de Óxido de Ferro/química , Resistência à Doença , Raízes de Plantas/parasitologia , Solo/parasitologia , Solo/química
15.
Planta ; 260(2): 36, 2024 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-38922545

RESUMO

MAIN CONCLUSION: Integrated management strategies, including novel nematicides and resilient cultivars, offer sustainable solutions to combat root-knot nematodes, crucial for safeguarding global agriculture against persistent threats. Root-knot nematodes (RKN) pose a significant threat to a diverse range of host plants, with their obligatory endoparasitic nature leading to substantial agricultural losses. RKN spend much of their lives inside or in contact by secreting plant cell wall-modifying enzymes resulting in the giant cell development for establishing host-parasite relationships. Additionally, inflicting physical harm to host plants, RKN also contributes to disease complexes creation with fungi and bacteria. This review comprehensively explores the origin, history, distribution, and physiological races of RKN, emphasizing their economic impact on plants through gall formation. Management strategies, ranging from cultural and physical to biological and chemical controls, along with resistance mechanisms and marker-assisted selection, are explored. While recognizing the limitations of traditional nematicides, recent breakthroughs in non-fumigant alternatives like fluensulfone, spirotetramat, and fluopyram offer promising avenues for sustainable RKN management. Despite the success of resistance mechanisms like the Mi gene, challenges persist, prompting the need for integrative approaches to tackle Mi-virulent isolates. In conclusion, the review stresses the importance of innovative and resilient control measures for sustainable agriculture, emphasizing ongoing research to address evolving challenges posed by RKN. The integration of botanicals, resistant cultivars, and biological controls, alongside advancements in non-fumigant nematicides, contributes novel insights to the field, laying the ground work for future research directions to ensure the long-term sustainability of agriculture in the face of persistent RKN threats.


Assuntos
Agricultura , Doenças das Plantas , Raízes de Plantas , Animais , Doenças das Plantas/parasitologia , Doenças das Plantas/prevenção & controle , Raízes de Plantas/parasitologia , Agricultura/métodos , Tylenchoidea/fisiologia , Tylenchoidea/patogenicidade , Interações Hospedeiro-Parasita , Resistência à Doença , Produtos Agrícolas/parasitologia , Antinematódeos/farmacologia
16.
New Phytol ; 242(1): 262-277, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38332248

RESUMO

Plants are simultaneously attacked by different pests that rely on sugars uptake from plants. An understanding of the role of plant sugar allocation in these multipartite interactions is limited. Here, we characterized the expression patterns of sucrose transporter genes and evaluated the impact of targeted transporter gene mutants and brown planthopper (BPH) phloem-feeding and oviposition on root sugar allocation and BPH-reduced rice susceptibility to Meloidogyne graminicola. We found that the sugar transporter genes OsSUT1 and OsSUT2 are induced at BPH oviposition sites. OsSUT2 mutants showed a higher resistance to gravid BPH than to nymph BPH, and this was correlated with callose deposition, as reflected in a different effect on M. graminicola infection. BPH phloem-feeding caused inhibition of callose deposition that was counteracted by BPH oviposition. Meanwhile, this pivotal role of sugar allocation in BPH-reduced rice susceptibility to M. graminicola was validated on rice cultivar RHT harbouring BPH resistance genes Bph3 and Bph17. In conclusion, we demonstrated that rice susceptibility to M. graminicola is regulated by BPH phloem-feeding and oviposition on rice through differences in plant sugar allocation.


Assuntos
Hemípteros , Oryza , Tylenchoidea , Animais , Feminino , Hemípteros/fisiologia , Açúcares/metabolismo , Oryza/metabolismo
17.
New Phytol ; 241(2): 878-895, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38044565

RESUMO

The establishment of root-knot nematode (RKN; Meloidogyne spp.) induced galls in the plant host roots likely involves a wound-induced regeneration response. Confocal imaging demonstrates physical stress or injury caused by RKN infection during parasitism in the model host Arabidopsis thaliana. The ERF115-PAT1 heterodimeric transcription factor complex plays a recognized role in wound-induced regeneration. ERF115 and PAT1 expression flanks injured gall cells likely driving mechanisms of wound healing, implying a local reactivation of cell division which is also hypothetically involved in gall genesis. Herein, functional investigation revealed that ectopic ERF115 expression resulted in premature induction of galls, and callus formation adjacent to the expanding female RKN was seen upon PAT1 upregulation. Smaller galls and less reproduction were observed in ERF115 and PAT1 knockouts. Investigation of components in the ERF115 network upon overexpression and knockdown by qRT-PCR suggests it contributes to steer gall wound-sensing and subsequent competence for tissue regeneration. High expression of CYCD6;1 was detected in galls, and WIND1 overexpression resulted in similar ERF115OE gall phenotypes, also showing faster gall induction. Along these lines, we show that the ERF115-PAT1 complex likely coordinates stress signalling with tissue healing, keeping the gall functional until maturation and nematode reproduction.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Tylenchoidea , Animais , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Ciclinas/metabolismo , Raízes de Plantas/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Tylenchoidea/fisiologia
18.
Plant Cell Environ ; 47(8): 2811-2820, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38679939

RESUMO

Plant-parasitic nematodes, specifically cyst nematodes (CNs) and root-knot nematodes (RKNs), pose significant threats to global agriculture, leading to substantial crop losses. Both CNs and RKNs induce permanent feeding sites in the root of their host plants, which then serve as their only source of nutrients throughout their lifecycle. Plants deploy reactive oxygen species (ROS) as a primary defense mechanism against nematode invasion. Notably, both CNs and RKNs have evolved sophisticated strategies to manipulate the host's redox environment to their advantage, with each employing distinct tactics to combat ROS. In this review, we have focused on the role of ROS and its scavenging network in interactions between host plants and CNs and RKNs. Overall, this review emphasizes the complex interplay between plant defense mechanism, redox signalling and nematode survival tactics, suggesting potential avenues for developing innovative nematode management strategies in agriculture.


Assuntos
Interações Hospedeiro-Parasita , Oxirredução , Doenças das Plantas , Plantas , Espécies Reativas de Oxigênio , Transdução de Sinais , Animais , Espécies Reativas de Oxigênio/metabolismo , Doenças das Plantas/parasitologia , Plantas/metabolismo , Plantas/parasitologia , Nematoides/fisiologia
19.
Chem Senses ; 492024 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-38695158

RESUMO

Gymnema sylvestre (GS) is a traditional medicinal plant known for its hypoglycemic and hypolipidemic effects. Gurmarin (hereafter Gur-1) is the only known active peptide in GS. Gur-1 has a suppressive sweet taste effect in rodents but no or only a very weak effect in humans. Here, 8 gurmarin-like peptides (Gur-2 to Gur-9) and their isoforms are reported in the GS transcriptome. The molecular mechanism of sweet taste suppression by Gur-1 is still largely unknown. Therefore, the complete architecture of human and mouse sweet taste receptors T1R2/T1R3 and their interaction with Gur-1 to Gur-9 were predicted by AlphaFold-Multimer (AF-M) and validated. Only Gur-1 and Gur-2 interact with the T1R2/T1R3 receptor. Indeed, Gur-1 and Gur-2 bind to the region of the cysteine-rich domain (CRD) and the transmembrane domain (TMD) of the mouse T1R2 subunit. In contrast, only Gur-2 binds to the TMD of the human T1R2 subunit. This result suggests that Gur-2 may have a suppressive sweet taste effect in humans. Furthermore, AF-M predicted that Gα-gustducin, a protein involved in sweet taste transduction, interacts with the intracellular domain of the T1R2 subunit. These results highlight an unexpected diversity of gurmarin-like peptides in GS and provide the complete predicted architecture of the human and mouse sweet taste receptor with the putative binding sites of Gur-1, Gur-2, and Gα-gustducin. In addition, gurmarin-like peptides may serve as promising drug scaffolds for the development of antidiabetic molecules.


Assuntos
Gymnema sylvestre , Receptores Acoplados a Proteínas G , Humanos , Gymnema sylvestre/metabolismo , Gymnema sylvestre/química , Animais , Camundongos , Receptores Acoplados a Proteínas G/metabolismo , Peptídeos/química , Peptídeos/farmacologia , Peptídeos/metabolismo , Proteínas de Plantas/metabolismo , Proteínas de Plantas/química , Paladar/fisiologia , Ligação Proteica , Sequência de Aminoácidos , Células HEK293
20.
Arch Microbiol ; 206(4): 160, 2024 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-38483595

RESUMO

Root-knot nematodes (RKN) are one of the most harmful soil-borne plant pathogens in the world. Actinobacteria are known phytopathogen control agents. The aim of this study was to select soil actinobacteria with control potential against the RKN (Meloidogyne javanica) in tomato plants and to determine mechanisms of action. Ten isolates were tested and a significant reduction was observed in the number of M. javanica eggs, and galls 46 days after infestation with the nematode. The results could be explained by the combination of different mechanisms including parasitism and induction of plant defense response. The M. javanica eggs were parasited by all isolates tested. Some isolates reduced the penetration of juveniles into the roots. Other isolates using the split-root method were able to induce systemic defenses in tomato plants. The 4L isolate was selected for analysis of the expression of the plant defense genes TomLoxA, ACCO, PR1, and RBOH1. In plants treated with 4L isolate and M. javanica, there was a significant increase in the number of TomLoxA and ACCO gene transcripts. In plants treated only with M. javanica, only the expression of the RBOH1 and PR1 genes was induced in the first hours after infection. The isolates were identified using 16S rRNA gene sequencing as Streptomyces sp. (1A, 3F, 4L, 6O, 8S, 9T, and 10U), Kribbella sp. (5N), Kitasatospora sp. (2AE), and Lentzea sp. (7P). The efficacy of isolates from the Kitasatospora, Kribbella, and Lentzea genera was reported for the first time, and the efficacy of Streptomyces genus isolates for controlling M. javanica was confirmed. All the isolates tested in this study were efficient against RKN. This study provides the opportunity to investigate bacterial genera that have not yet been explored in the control of M. javanica in tomatoes and other crops.


Assuntos
Actinobacteria , Actinomycetales , Solanum lycopersicum , Tylenchoidea , Animais , Doenças das Plantas/prevenção & controle , Tylenchoidea/genética , Actinobacteria/genética , RNA Ribossômico 16S/genética , Bactérias/genética , Actinomycetales/genética , Solo
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