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1.
Nat Commun ; 11(1): 208, 2020 01 10.
Artigo em Inglês | MEDLINE | ID: mdl-31924834

RESUMO

Microorganisms and nematodes in the rhizosphere profoundly impact plant health, and small-molecule signaling is presumed to play a central role in plant rhizosphere interactions. However, the nature of the signals and underlying mechanisms are poorly understood. Here we show that the ascaroside ascr#18, a pheromone secreted by plant-parasitic nematodes, is metabolized by plants to generate chemical signals that repel nematodes and reduce infection. Comparative metabolomics of plant tissues and excretions revealed that ascr#18 is converted into shorter side-chained ascarosides that confer repellency. An Arabidopsis mutant defective in two peroxisomal acyl-CoA oxidases does not metabolize ascr#18 and does not repel nematodes, indicating that plants, like nematodes, employ conserved peroxisomal ß-oxidation to edit ascarosides and change their message. Our results suggest that plant-editing of nematode pheromones serves as a defense mechanism that acts in parallel to conventional pattern-triggered immunity, demonstrating that plants may actively manipulate chemical signaling of soil organisms.


Assuntos
Arabidopsis/metabolismo , Arabidopsis/parasitologia , Interações Hospedeiro-Parasita/fisiologia , Nematoides/metabolismo , Feromônios/metabolismo , Acil-CoA Oxidase , Animais , Arabidopsis/imunologia , Lycopersicon esculentum , Metabolômica , Oxirredução , Doenças das Plantas/imunologia , Doenças das Plantas/parasitologia , Imunidade Vegetal , Raízes de Plantas/metabolismo , Transdução de Sinais , Triticum
2.
Sci Rep ; 10(1): 1390, 2020 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-31996697

RESUMO

The need for larger-scale and increasingly complex protein-protein interaction (PPI) prediction tasks demands that state-of-the-art predictors be highly efficient and adapted to inter- and cross-species predictions. Furthermore, the ability to generate comprehensive interactomes has enabled the appraisal of each PPI in the context of all predictions leading to further improvements in classification performance in the face of extreme class imbalance using the Reciprocal Perspective (RP) framework. We here describe the PIPE4 algorithm. Adaptation of the PIPE3/MP-PIPE sequence preprocessing step led to upwards of 50x speedup and the new Similarity Weighted Score appropriately normalizes for window frequency when applied to any inter- and cross-species prediction schemas. Comprehensive interactomes for three prediction schemas are generated: (1) cross-species predictions, where Arabidopsis thaliana is used as a proxy to predict the comprehensive Glycine max interactome, (2) inter-species predictions between Homo sapiens-HIV1, and (3) a combined schema involving both cross- and inter-species predictions, where both Arabidopsis thaliana and Caenorhabditis elegans are used as proxy species to predict the interactome between Glycine max (the soybean legume) and Heterodera glycines (the soybean cyst nematode). Comparing PIPE4 with the state-of-the-art resulted in improved performance, indicative that it should be the method of choice for complex PPI prediction schemas.


Assuntos
Biologia Computacional/métodos , Interações Hospedeiro-Patógeno , Metabolômica/métodos , Modelos Biológicos , Mapeamento de Interação de Proteínas/métodos , Animais , Arabidopsis/metabolismo , Arabidopsis/parasitologia , Drosophila melanogaster/metabolismo , HIV-1/metabolismo , Humanos , Camundongos , Mapas de Interação de Proteínas/fisiologia , Rabditídios/metabolismo , Saccharomyces cerevisiae/metabolismo , Soja/metabolismo , Soja/parasitologia
3.
Mol Plant Microbe Interact ; 33(2): 328-335, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31702436

RESUMO

Plants have evolved mechanisms to protect themselves against pathogenic microbes and insect pests. In Arabidopsis, the immune regulator PAD4 functions with its cognate partner EDS1 to limit pathogen growth. PAD4, independently of EDS1, reduces infestation by green peach aphid (GPA). How PAD4 regulates these defense outputs is unclear. By expressing the N-terminal PAD4 lipase-like domain (PAD4LLD) without its C-terminal EDS1-PAD4 (EP) domain, we interrogated PAD4 functions in plant defense. Here, we show that transgenic expression of PAD4LLD in Arabidopsis is sufficient for limiting GPA infestation but not for conferring basal and effector-triggered pathogen immunity. This suggests that the C-terminal PAD4 EP domain is necessary for EDS1-dependent immune functions but is dispensable for aphid resistance. Moreover, PAD4LLD is not sufficient to interact with EDS1, indicating the PAD4-EP domain is required for stable heterodimerization. These data provide molecular evidence that PAD4 has domain-specific functions.


Assuntos
Afídeos , Arabidopsis , Resistência à Doença , Domínios Proteicos , Animais , Afídeos/fisiologia , Arabidopsis/enzimologia , Arabidopsis/genética , Arabidopsis/parasitologia , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Hidrolases de Éster Carboxílico/genética , Hidrolases de Éster Carboxílico/metabolismo , Resistência à Doença/genética , Regulação da Expressão Gênica de Plantas , Domínios Proteicos/genética , Domínios Proteicos/fisiologia
4.
Proc Natl Acad Sci U S A ; 116(51): 26066-26071, 2019 12 17.
Artigo em Inglês | MEDLINE | ID: mdl-31792188

RESUMO

Slow wave potentials (SWPs) are damage-induced electrical signals which, based on experiments in which organs are burned, have been linked to rapid increases in leaf or stem thickness. The possibility that pressure surges in injured xylem underlie these events has been evoked frequently. We sought evidence for insect feeding-induced positive pressure changes in the petioles of Arabidopsis thaliana Instead, we found that petiole surfaces of leaves distal to insect-feeding sites subsided. We also found that insect damage induced longer-duration downward leaf movements in undamaged leaves. The transient petiole deformations were contemporary with and dependent on the SWP. We then investigated if mutants that affect the xylem, which has been implicated in SWP transmission, might modify SWP architecture. irregular xylem mutants strongly affected SWP velocity and kinetics and, in parallel, restructured insect damage-induced petiole deformations. Together, with force change measurements on the primary vein, the results suggest that extravascular water fluxes accompany the SWP. Moreover, petiole deformations in Arabidopsis mimic parts of the spectacular distal leaf collapse phase seen in wounded Mimosa pudica We genetically link electrical signals to organ movement and deformation and suggest an evolutionary origin of the large leaf movements seen in wounded Mimosa.


Assuntos
Arabidopsis/fisiologia , Arabidopsis/parasitologia , Insetos/fisiologia , Mimosa/fisiologia , Folhas de Planta/fisiologia , Folhas de Planta/parasitologia , Animais , Estimulação Elétrica , Eletricidade , Cinética , Larva/fisiologia , Lepidópteros/fisiologia , Fenômenos Fisiológicos Vegetais , Xilema
5.
Molecules ; 25(1)2019 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-31861560

RESUMO

Apocarotenoids, such as ß-cyclocitral, α-ionone, ß-ionone, and loliolide, are derived from carotenes via chemical or enzymatic processes. Recent studies revealed that ß-cyclocitral and loliolide play an important role in various aspects of plant physiology, such as stress responses, plant growth, and herbivore resistance. However, information on the physiological role of α-ionone is limited. We herein investigated the effects of α-ionone on plant protection against herbivore attacks. The pretreatment of whole tomato (Solanum lycopersicum) plants with α-ionone vapor decreased the survival rate of western flower thrips (Frankliniella occidentalis) without exhibiting insecticidal activity. Exogenous α-ionone enhanced the expression of defense-related genes, such as basic ß-1,3-glucanase and basic chitinase genes, in tomato leaves, but not that of jasmonic acid (JA)- or loliolide-responsive genes. The pretreatment with α-ionone markedly decreased egg deposition by western flower thrips in the JA-insensitive Arabidopsis (Arabidopsis thaliana) mutant coi1-1. We also found that common cutworm (Spodoptera litura) larvae fed on α-ionone-treated tomato plants exhibited a reduction in weight. These results suggest that α-ionone induces plant resistance to western flower thrips through a different mode of action from that of JA and loliolide.


Assuntos
Resistência à Doença , Lycopersicon esculentum/efeitos dos fármacos , Norisoprenoides/farmacologia , Tisanópteros/efeitos dos fármacos , Animais , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Arabidopsis/parasitologia , Ciclopentanos/metabolismo , Feminino , Flores/efeitos dos fármacos , Flores/parasitologia , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Lycopersicon esculentum/genética , Lycopersicon esculentum/parasitologia , Oxilipinas/metabolismo , Doenças das Plantas/genética , Doenças das Plantas/parasitologia , Doenças das Plantas/prevenção & controle , Proteínas de Plantas/genética
6.
Elife ; 82019 12 17.
Artigo em Inglês | MEDLINE | ID: mdl-31845648

RESUMO

Trans-species small regulatory RNAs (sRNAs) are delivered to host plants from diverse pathogens and parasites and can target host mRNAs. How trans-species sRNAs can be effective on diverse hosts has been unclear. Multiple species of the parasitic plant Cuscuta produce trans-species sRNAs that collectively target many host mRNAs. Confirmed target sites are nearly always in highly conserved, protein-coding regions of host mRNAs. Cuscuta trans-species sRNAs can be grouped into superfamilies that have variation in a three-nucleotide period. These variants compensate for synonymous-site variation in host mRNAs. By targeting host mRNAs at highly conserved protein-coding sites, and simultaneously expressing multiple variants to cover synonymous-site variation, Cuscuta trans-species sRNAs may be able to successfully target multiple homologous mRNAs from diverse hosts.


Assuntos
Arabidopsis/parasitologia , Cuscuta/genética , Regulação da Expressão Gênica de Plantas , Genoma de Planta , RNA Mensageiro/genética , Pequeno RNA não Traduzido/genética , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Sequência de Bases , Códon , Biologia Computacional , Sequência Conservada , Cuscuta/crescimento & desenvolvimento , Cuscuta/metabolismo , Variação Genética , Interações Hospedeiro-Parasita , Fases de Leitura Aberta , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , RNA Mensageiro/classificação , RNA Mensageiro/metabolismo , RNA de Plantas/genética , RNA de Plantas/metabolismo , Pequeno RNA não Traduzido/classificação , Pequeno RNA não Traduzido/metabolismo , Alinhamento de Sequência , Tabaco/genética , Tabaco/crescimento & desenvolvimento , Tabaco/parasitologia
7.
Int J Mol Sci ; 20(21)2019 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-31684028

RESUMO

Meloidogyne incognita is a root knot nematode (RKN) species which is among the most notoriously unmanageable crop pests with a wide host range. It inhabits plants and induces unique feeding site structures within host roots, known as giant cells (GCs). The cell walls of the GCs undergo the process of both thickening and loosening to allow expansion and finally support nutrient uptake by the nematode. In this study, a comparative in situ analysis of cell wall polysaccharides in the GCs of wild-type Col-0 and the microtubule-defective fra2 katanin mutant, both infected with M. incognita has been carried out. The fra2 mutant had an increased infection rate. Moreover, fra2 roots exhibited a differential pectin and hemicellulose distribution when compared to Col-0 probably mirroring the fra2 root developmental defects. Features of fra2 GC walls include the presence of high-esterified pectic homogalacturonan and pectic arabinan, possibly to compensate for the reduced levels of callose, which was omnipresent in GCs of Col-0. Katanin severing of microtubules seems important in plant defense against M. incognita, with the nematode, however, to be nonchalant about this "katanin deficiency" and eventually induce the necessary GC cell wall modifications to establish a feeding site.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Parede Celular/metabolismo , Células Gigantes/metabolismo , Katanina/metabolismo , Raízes de Plantas/metabolismo , Animais , Arabidopsis/genética , Arabidopsis/parasitologia , Proteínas de Arabidopsis/genética , Parede Celular/parasitologia , Regulação da Expressão Gênica de Plantas , Células Gigantes/parasitologia , Interações Hospedeiro-Parasita , Katanina/genética , Microtúbulos/metabolismo , Mutação , Pectinas/metabolismo , Doenças das Plantas/genética , Doenças das Plantas/parasitologia , Raízes de Plantas/genética , Raízes de Plantas/parasitologia , Polissacarídeos/metabolismo , Tylenchoidea/fisiologia
8.
Phytopathology ; 109(12): 2107-2115, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31403912

RESUMO

Cyst nematodes consistently threaten agricultural production, causing billions of dollars in losses globally. The Rhg1 (resistance to Heterodera glycines 1) locus of soybean (Glycine max) is the most popular resistance source used against soybean cyst nematodes (H. glycines). Rhg1 is a complex locus that has multiple repeats of an ≈30-kilobase segment carrying three genes that contribute to resistance. We investigated whether soybean Rhg1 could function in different plant families, conferring resistance to their respective cyst nematode parasites. Transgenic Arabidopsis thaliana and potato (Solanum tuberosum) plants expressing the three soybean Rhg1 genes were generated. The recipient Brassicaceae and Solanaceae plant species exhibited elevated resistance to H. schachtii and Globodera rostochiensis and to G. pallida, respectively. However, some negative consequences including reduced root growth and tuber biomass were observed upon Rhg1 expression in heterologous species. One of the genes at Rhg1 encodes a toxic version of an alpha-SNAP protein that has been demonstrated to interfere with vesicle trafficking. Using a transient expression assay for Nicotiana benthamiana, native Arabidopsis and potato alpha-SNAPs (soluble NSF [N-ethylamine sensitive factor] attachment protein) were found to compensate for the toxicity of soybean Rhg1 alpha-SNAP proteins. Hence, future manipulation of the balance between Rhg1 alpha-SNAP and the endogenous wild-type alpha-SNAPs (as well as the recently discovered soybean NSF-RAN07) may mitigate impacts of Rhg1 on plant productivity. The multispecies efficacy of soybean Rhg1 demonstrates that the encoded mechanisms can function across plant and cyst nematode species and offers a possible avenue for engineered resistance in diverse crop species.


Assuntos
Arabidopsis , Resistência à Doença , Plantas Geneticamente Modificadas , Solanum tuberosum , Soja , Tylenchoidea , Animais , Arabidopsis/genética , Arabidopsis/parasitologia , Resistência à Doença/genética , Doenças das Plantas/parasitologia , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/parasitologia , Solanum tuberosum/genética , Solanum tuberosum/parasitologia , Soja/genética , Soja/parasitologia , Tylenchoidea/fisiologia
9.
BMC Plant Biol ; 19(1): 334, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31370799

RESUMO

BACKGROUND: Parasitic plants engage in a complex molecular dialog with potential host plants to identify a host and overcome host defenses to initiate development of the parasitic feeding organ, the haustorium, invade host tissues, and withdraw water and nutrients. While one of two critical signaling events in the parasitic plant life cycle (germination via stimulant chemicals) has been relatively well-studied, the signaling event that triggers haustorium formation remains elusive. Elucidation of this poorly understood molecular dialogue will shed light on plant-plant communication, parasitic plant physiology, and the evolution of parasitism in plants. RESULTS: Here we present an experimental framework that develops easily quantifiable contrasts for the facultative generalist parasitic plant, Triphysaria, as it feeds across a broad range of diverse flowering plants. The contrasts, including variable parasite growth form and mortality when grown with different hosts, suggest a dynamic and host-dependent molecular dialogue between the parasite and host. Finally, by comparing transcriptome datasets from attached versus unattached parasites we gain insight into some of the physiological processes that are altered during parasitic behavior including shifts in photosynthesis-related and stress response genes. CONCLUSIONS: This work sheds light on Triphysaria's parasitic life habit and is an important step towards understanding the mechanisms of haustorium initiation factor perception, a unique form of plant-plant communication.


Assuntos
Interações Hospedeiro-Parasita , Magnoliopsida/parasitologia , Orobanchaceae/fisiologia , Arabidopsis/parasitologia , Magnoliopsida/fisiologia , Medicago/parasitologia , Oryza/parasitologia , Solanum/parasitologia , Zea mays/parasitologia
10.
Toxins (Basel) ; 11(6)2019 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-31163681

RESUMO

Vegetative insecticidal proteins (Vips) from Bacillus thuringiensis (Bt) are unique from crystal (Cry) proteins found in Bt parasporal inclusions as they are secreted during the bacterial vegetative growth phase and bind unique receptors to exert their insecticidal effects. We previously demonstrated that large modifications of the Vip3 C-terminus could redirect insecticidal spectrum but results in an unstable protein with no lethal activity. In the present work, we have generated a new Vip3 protein, Vip3Ab1-740, via modest modification of the Vip3Ab1 C-terminus. Vip3Ab1-740 is readily processed by midgut fluid enzymes and has lethal activity towards Spodoptera eridania, which is not observed with the Vip3Ab1 parent protein. Importantly, Vip3Ab1-740 does retain the lethal activity of Vip3Ab1 against other important lepidopteran pests. Furthermore, transgenic plants expressing Vip3Ab1-740 are protected against S. eridania, Spodoptera frugiperda, Helicoverpa zea, and Pseudoplusia includens. Thus, these studies demonstrate successful engineering of Vip3 proteins at the C-terminus to broaden insecticidal spectrum, which can be employed for functional expression in planta.


Assuntos
Arabidopsis/parasitologia , Proteínas de Bactérias/genética , Controle Biológico de Vetores , Plantas Geneticamente Modificadas/parasitologia , Spodoptera/fisiologia , Animais , Arabidopsis/genética , Inseticidas
11.
Int J Mol Sci ; 20(12)2019 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-31212812

RESUMO

Although the date palm tree is an extremophile with tolerance to drought and certain levels of salinity, the damage caused by extreme salt concentrations in the soil, has created a need to explore stress-responsive traits and decode their mechanisms. Metallothioneins (MTs) are low-molecular-weight cysteine-rich proteins that are known to play a role in decreasing oxidative damage during abiotic stress conditions. Our previous study identified date palm metallothionein 2A (PdMT2A) as a salt-responsive gene, which has been functionally characterized in yeast and Arabidopsis in this study. The recombinant PdMT2A protein produced in Escherichia coli showed high reactivity against the substrate 5'-dithiobis-2-nitrobenzoic acid (DTNB), implying that the protein has the property of scavenging reactive oxygen species (ROS). Heterologous overexpression of PdMT2A in yeast (Saccharomyces cerevisiae) conferred tolerance to drought, salinity and oxidative stresses. The PdMT2A gene was also overexpressed in Arabidopsis, to assess its stress protective function in planta. Compared to the wild-type control, the transgenic plants accumulated less Na+ and maintained a high K+/Na+ ratio, which could be attributed to the regulatory role of the transgene on transporters such as HKT, as demonstrated by qPCR assay. In addition, transgenic lines exhibited higher chlorophyll content, higher superoxide dismutase (SOD) activity and improved scavenging ability for reactive oxygen species (ROS), coupled with a better survival rate during salt stress conditions. Similarly, the transgenic plants also displayed better drought and oxidative stress tolerance. Collectively, both in vitro and in planta studies revealed a role for PdMT2A in salt, drought, and oxidative stress tolerance.


Assuntos
Adaptação Biológica , Resistência à Doença/genética , Expressão Gênica , Metalotioneína/genética , Phoeniceae/fisiologia , Doenças das Plantas/genética , Estresse Fisiológico/genética , Sequência de Aminoácidos , Arabidopsis/microbiologia , Arabidopsis/parasitologia , Arabidopsis/fisiologia , Secas , Metalotioneína/química , Estresse Oxidativo , Fenótipo , Phoeniceae/classificação , Phoeniceae/microbiologia , Phoeniceae/parasitologia , Filogenia , Doenças das Plantas/microbiologia , Doenças das Plantas/parasitologia , Plantas Geneticamente Modificadas , Salinidade , Plantas Tolerantes a Sal , Plântula , Solo
12.
Mol Plant Microbe Interact ; 32(11): 1487-1495, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31241412

RESUMO

Phytoplasmas are the causative agent of numerous diseases of plant species all over the world, including important food crops. The mode by which phytoplasmas multiply and behave in their host is poorly understood and often based on genomic data. We used yeast two-hybrid screening to find new protein-protein interactions between the causal agent of apple proliferation 'Candidatus Phytoplasma mali' and its host plant. Here, we report that the 'Ca. P. mali' strain PM19 genome encodes a protein PM19_00185 that interacts with at least six different ubiquitin-conjugating enzymes (UBC; E2) of Arabidopsis thaliana. An in vitro ubiquitination assay showed that PM19_00185 is enzymatically active as E3 ligase with A. thaliana E2 UBC09 and Malus domestica E2 UBC10. We show that a nonhost bacteria (Pseudomonas syringae pv. tabaci) can grow in transgenic A. thaliana plant lines expressing PM19_00185. A connection of phytoplasma effector proteins with the proteasome proteolytic pathway has been reported before. However, this is, to our knowledge, the first time that a phytoplasma effector protein with E3 ligase activity has been reported.


Assuntos
Phytoplasma , Doenças das Plantas , Ubiquitina-Proteína Ligases , Arabidopsis/enzimologia , Arabidopsis/parasitologia , Malus/parasitologia , Phytoplasma/enzimologia , Phytoplasma/genética , Doenças das Plantas/imunologia , Doenças das Plantas/parasitologia , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/imunologia , Ubiquitina-Proteína Ligases/metabolismo
13.
Mol Plant Microbe Interact ; 32(10): 1259-1266, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31210556

RESUMO

When plants are infected by Plasmodiophora brassicae, their developmental programs are subjected to extensive changes and the resultant clubroot disease is associated with formation of large galls on underground tissue. The pathogen's need to build an efficient feeding site as the disease progresses drives these changes, ensuring successful production of resting spores. This developmental reprogramming is an outcome of interactions between the pathogen and the infected host. During disease progression, we can observe alteration of growth regulator dynamics, patterns of cell proliferation and differentiation, increased cell expansion, and eventual cell wall degradation as well as the redirection of nutrients toward the pathogen. Recently, detailed studies of anatomical changes occurring during infection and studies profiling transcriptional responses have come together to provide a clearer understanding of the sequence of events and processes underlying clubroot disease. Additionally, genome sequencing projects have revealed P. brassicae's potential for the production of signaling molecules and effectors as well as its requirements and capacities with respect to taking up host nutrients. Integration of these new findings together with physiological studies can significantly advance our understanding of how P. brassicae brings about reprogramming of host development. This article summarizes the current state of knowledge on cellular changes induced by P. brassicae infection and aims to explain their impact and importance for both the host and the pathogen.


Assuntos
Arabidopsis , Interações Hospedeiro-Parasita , Plasmodioforídeos , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/parasitologia , Interações Hospedeiro-Parasita/fisiologia , Doenças das Plantas/parasitologia , Plasmodioforídeos/fisiologia
14.
Plant Cell ; 31(7): 1539-1562, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31076540

RESUMO

Cellular calcium elevation is an important signal used by plants for recognition and signaling of environmental stress. Perception of the generalist insect, Spodoptera litura, by Arabidopsis (Arabidopsis thaliana) activates cytosolic Ca2+ elevation, which triggers downstream defense. However, not all the Ca2+ channels generating the signal have been identified, nor are their modes of action known. We report on a rapidly activated, leaf vasculature- and plasma membrane-localized, CYCLIC NUCLEOTIDE GATED CHANNEL19 (CNGC19), which activates herbivory-induced Ca2+ flux and plant defense. Loss of CNGC19 function results in decreased herbivory defense. The cngc19 mutant shows aberrant and attenuated intravascular Ca2+ fluxes. CNGC19 is a Ca2+-permeable channel, as hyperpolarization of CNGC19-expressing Xenopus oocytes in the presence of both cyclic adenosine monophosphate and Ca2+ results in Ca2+ influx. Breakdown of Ca2+-based defense in cngc19 mutants leads to a decrease in herbivory-induced jasmonoyl-l-isoleucine biosynthesis and expression of JA responsive genes. The cngc19 mutants are deficient in aliphatic glucosinolate accumulation and hyperaccumulate its precursor, methionine. CNGC19 modulates aliphatic glucosinolate biosynthesis in tandem with BRANCHED-CHAIN AMINO ACID TRANSAMINASE4, which is involved in the chain elongation pathway of Met-derived glucosinolates. Furthermore, CNGC19 interacts with herbivory-induced CALMODULIN2 in planta. Together, our work reveals a key mechanistic role for the Ca2+ channel CNGC19 in the recognition of herbivory and the activation of defense signaling.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Arabidopsis/parasitologia , Herbivoria/fisiologia , Spodoptera/fisiologia , Animais , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Cálcio/metabolismo , Sinalização do Cálcio/efeitos dos fármacos , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Permeabilidade da Membrana Celular/efeitos dos fármacos , Ciclopentanos/farmacologia , Citosol/efeitos dos fármacos , Citosol/metabolismo , Regulação para Baixo/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Glucosinolatos/metabolismo , Herbivoria/efeitos dos fármacos , Metionina/metabolismo , Modelos Biológicos , Mutação/genética , Oxilipinas/farmacologia , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/parasitologia , Feixe Vascular de Plantas/efeitos dos fármacos , Feixe Vascular de Plantas/genética , Ligação Proteica/efeitos dos fármacos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Transdução de Sinais/efeitos dos fármacos , Spodoptera/efeitos dos fármacos , Xenopus
15.
Plant Physiol Biochem ; 140: 55-67, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31082659

RESUMO

Plants express various antimicrobial peptides including thionins to protect themselves against pathogens. It was recently found that, in addition to four thionin genes, Arabidopsis contains 67 thionin-like (ThiL) genes including six pseudogenes. It is known that thionins have antimicrobial activity and are part of the plant defense system, however, nothing is known about ThiL genes. In this study, we present a bioinformatic analysis of the (ThiL) gene family in Arabidopsis. We identified 15 different motifs which positioned the ThiL peptides in four groups. A comparison of amino acid sequences showed that the ThiL peptides are actually more similar to the acidic domain of thionin proproteins than to the thionin domain. We selected 10 ThiL genes to study the expression and possible function in the Arabidopsis plant. RT-PCR and promoter:GUS fusions showed that most genes were expressed at a very low level but in several organs and at different developmental stages. Some genes were also expressed in syncytia induced by the beet cyst nematode Heterodera schachti in roots while others were downregulated in syncytia. Some overexpression lines supported lower number of nematodes that developed on the roots after inoculation. Two of the genes resulted in a strong hypersensitive response when infiltrated into leaves of Nicotiana benthamiana. These results indicate that ThiL genes might be involved in the response to biotic stress. ThiL genes have been expanded in the Brassicales and specifically the Brassicaceae. The most extreme example is the CRP2460 subfamily that contains 28 very closely related genes from Arabidopsis which are mostly the result of tandem duplications.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Arabidopsis/parasitologia , Proteínas de Arabidopsis/genética , Biologia Computacional/métodos , Regulação da Expressão Gênica de Plantas/genética , Regulação da Expressão Gênica de Plantas/fisiologia , Folhas de Planta/genética , Folhas de Planta/metabolismo , Regiões Promotoras Genéticas/genética , Tioninas/genética , Tioninas/metabolismo
16.
Plant Cell ; 31(8): 1913-1929, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31126981

RESUMO

Because they suck phloem sap and act as vectors for phytopathogenic viruses, aphids pose a threat to crop yields worldwide. Pectic homogalacturonan (HG) has been described as a defensive element for plants during infections with phytopathogens. However, its role during aphid infestation remains unexplored. Using immunofluorescence assays and biochemical approaches, the HG methylesterification status and associated modifying enzymes during the early stage of Arabidopsis (Arabidopsis thaliana) infestation with the green peach aphid (Myzus persicae) were analyzed. Additionally, the influence of pectin methylesterase (PME) activity on aphid settling and feeding behavior was evaluated by free choice assays and the Electrical Penetration Graph technique, respectively. Our results revealed that HG status and HG-modifying enzymes are significantly altered during the early stage of the plant-aphid interaction. Aphid infestation induced a significant increase in total PME activity and methanol emissions, concomitant with a decrease in the degree of HG methylesterification. Conversely, inhibition of PME activity led to a significant decrease in the settling and feeding preference of aphids. Furthermore, we demonstrate that the PME inhibitor AtPMEI13 has a defensive role during aphid infestation, since pmei13 mutants are significantly more susceptible to M. persicae in terms of settling preference, phloem access, and phloem sap drainage.


Assuntos
Afídeos/patogenicidade , Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Arabidopsis/parasitologia , Pectinas/metabolismo , Animais , Arabidopsis/enzimologia , Proteínas de Arabidopsis/genética , Regulação da Expressão Gênica de Plantas
17.
Plant Signal Behav ; 14(7): 1610300, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31025584

RESUMO

Soluble N-ethylmaleimide sensitive factor attachment protein receptors (SNAREs) are the key regulators control trafficking of cargo proteins to their final destinations and plays key role in plant development; however, their roles in plant defense remain largely unknown. R-SNARE VAMP727 and Qa-SNARE SYP22 were previously reported to associate with vacuolar protein deposition and brassinosteroids (BRs) receptor BRI1 plasma membrane targeting. Here, we identified that VAMP727 and SYP22 are induced by infection of root-knot nematode (RKN), a plant pathogen, which cause severe growth defect and yield loss. Furthermore, decreased root-knot nematode (RKN) invasion, growth and disease index were observed in bri1-5 and SYP22ND, a SYP22 negative dominant mutants when compared to control plants. Overall, our results suggest that VAMP727-SYP22 SNARE complexes regulate plant defense might be via control of abundances of BRI1 on the plasma membrane.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/imunologia , Arabidopsis/metabolismo , Imunidade Vegetal , Proteínas Qa-SNARE/metabolismo , Proteínas SNARE/metabolismo , Animais , Arabidopsis/genética , Arabidopsis/parasitologia , Brassinosteroides/metabolismo , Regulação da Expressão Gênica de Plantas , Mutação/genética , Tumores de Planta/parasitologia , Tylenchoidea/fisiologia
18.
PLoS One ; 14(4): e0216082, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31022256

RESUMO

The elicitor Hrip1 isolated from necrotrophic fungus Alternaria tenuissima, could induce systemic acquired resistance in tobacco to enhance resistance to tobacco mosaic virus. In the present study, we found that the transgenic lines of Hrip1-overexpression in wild type (WT) Arabidopsis thaliana were more resistant to Spodoptera exigua and were early bolting and flowering than the WT. A profiling of transcription assay using digital gene expression profiling was used for transgenic and WT Arabidopsis thaliana. Differentially expressed genes including 40 upregulated and three downregulated genes were identified. In transgenic lines of Hrip1-overexpression, three genes related to jasmonate (JA) biosynthesis were significantly upregulated, and the JA level was found to be higher than WT. Two GDSL family members (GLIP1 and GLIP4) and pathogen-related gene, which participated in pathogen defense action, were upregulated in the transgenic line of Hrip1-overexpression. Thus, Hrip1 is involved in affecting the flower bolting time and regulating endogenous JA biosynthesis and regulatory network to enhance resistance to insect.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Arabidopsis/parasitologia , Resistência à Doença , Flores/fisiologia , Doenças das Plantas/imunologia , Doenças das Plantas/parasitologia , Spodoptera/fisiologia , Animais , Arabidopsis/imunologia , Proteínas de Arabidopsis/genética , Ciclopentanos/metabolismo , Regulação da Expressão Gênica de Plantas , Oxilipinas/metabolismo , Fotoperíodo , Plantas Geneticamente Modificadas , Reprodutibilidade dos Testes
19.
BMC Plant Biol ; 19(1): 163, 2019 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-31029092

RESUMO

BACKGROUND: Genetic variation in plants alters insect abundance and community structure in the field; however, little is known about the importance of a single gene among diverse plant genotypes. In this context, Arabidopsis trichomes provide an excellent system to discern the roles of natural variation and a key gene, GLABRA1, in shaping insect communities. In this study, we transplanted two independent glabrous mutants (gl1-1 and gl1-2) and 17 natural accessions of Arabidopsis thaliana to two localities in Switzerland and Japan. RESULTS: Fifteen insect species inhabited the plant accessions, with the insect community composition significantly attributed to variations among plant accessions. The total abundance of leaf-chewing herbivores was negatively correlated with trichome density at both field sites, while glucosinolates had variable effects on leaf chewers between the sites. Interestingly, there was a parallel tendency for the abundance of leaf chewers to be higher on gl1-1 and gl1-2 than on their different parental accessions, Ler-1 and Col-0, respectively. Furthermore, the loss of function in the GLABRA1 gene significantly decreased the resistance of plants to the two predominant chewers; flea beetles and turnip sawflies. CONCLUSIONS: Overall, our results indicate that insect community composition significantly varies among A. thaliana accessions across two distant field sites, with GLABRA1 playing a key role in altering the abundance of leaf-chewing herbivores. Given that such a trichome variation is widely observed in Brassicaceae plants, the present study exemplifies the community-wide effect of a single plant gene on crucifer-feeding insects in the field.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/genética , Arabidopsis/parasitologia , Proteínas de Ligação a DNA/genética , Genes de Plantas , Insetos/fisiologia , Tricomas/metabolismo , Animais , Arabidopsis/crescimento & desenvolvimento , Ecótipo , Característica Quantitativa Herdável , Estações do Ano , Especificidade da Espécie
20.
Plant Signal Behav ; 14(7): 1607466, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31021696

RESUMO

Priming for better defense performance is an important strategy in acclimation to the ever-changing environment. In the present study, defense priming induced by sodium chloride at the seedling stage significantly increased the expression of defense gene VSP2, the content of total glucosinolates and the level of the reactive oxygen species in mature Arabidopsis thaliana plants after transferred into the stress-free environment. The previously primed plants could effectively resist the feeding of Spodoptera litura (Fabricius) larvae. Salt-priming enhanced defense of Arabidopsis plants in the absence of either MYC2 or AOS, which encodes a critical transcription factor in JA-signaling and an important enzyme in JA biosynthesis, respectively. Our results supported the JA-independent defense primed by sodium chloride, as well as the elevated ROS and glucosinolate level in primed plants. In addition, the feasibility of using mild salt-priming to improve crop performance in field was proposed.


Assuntos
Arabidopsis/imunologia , Arabidopsis/parasitologia , Ciclopentanos/farmacologia , Oxilipinas/farmacologia , Cloreto de Sódio/farmacologia , Spodoptera/fisiologia , Animais , Comportamento Alimentar/efeitos dos fármacos , Glucosinolatos/metabolismo , Larva/efeitos dos fármacos , Larva/fisiologia , Mutação/genética , Espécies Reativas de Oxigênio/metabolismo , Spodoptera/efeitos dos fármacos
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