scholarly journals A triresidue motif in the GLUTAMATE RECEPTOR-LIKE 3.3 C-tail interacts with IMPAIRED SUCROSE INDUCTION 1 and controls long distance wound signaling

2020 ◽  
Author(s):  
Qian Wu ◽  
Stéphanie Stolz ◽  
Archana Kumari ◽  
Gaétan Glauser ◽  
Edward E. Farmer
Keyword(s):  
Glutamate Receptor ◽  
Gene Activation ◽  
Underlying Mechanism ◽  
Defense Responses ◽  
In Planta ◽  
Animal Cells ◽  
Long Distance ◽  
Sucrose Induction ◽  
Wound Signaling ◽  
Electrical Signaling

AbstractArabidopsis Clade 3 GLUTAMATE RECEPTOR-LIKE (GLRs) genes are primary players in wound-induced electrical signaling and jasmonate-activated defense responses. As cation-permeable ion channels, previous studies have focused on resolving their gating properties and structures. However, little is known regarding to the regulatory mechanism of these channel proteins. Here, we report that the C-tail of GLR3.3 contains key elements that control its function in long distance wound signaling. GLR3.3 without its C-tail failed to rescue the glr3.3a mutant. To further investigate the underlying mechanism, we performed a yeast two-hybrid screen. IMPAIRED SUCROSE INDUCTION 1 (ISI1) was identified as an interactor with both the C-tail and the full-length GLR3.3 in planta. Reduced function isi1 mutants had enhanced electrical activity and jasmonate-regulated defense responses. Furthermore, we found that a triresidue motif RFL (R884, F885 and L886) in the GLR3.3 C-tail is essential for interacting with ISI1. RFL mutation abolished GLR3.3 function in electrical signaling and jasmonate-mediated defense gene activation. Our study shows the importance of the C-tail in GLR3.3 function, and reveals parallels with the ipnotropic glutamate receptor regulation in animal cells.

Glutamate triggers long-distance, calcium-based plant defense signaling

Science ◽  
2018 ◽  
Vol 361 (6407) ◽  
pp. 1112-1115 ◽  
Author(s):  
Masatsugu Toyota ◽  
Dirk Spencer ◽  
Satoe Sawai-Toyota ◽  
Wang Jiaqi ◽  
Tong Zhang ◽  
...  
Keyword(s):  
Long Range ◽  
Glutamate Receptor ◽  
Information Exchange ◽  
Defense Responses ◽  
Ion Concentration ◽  
Molecular Signaling ◽  
Long Distance ◽  
Excitatory Neurotransmitter ◽  
Intracellular Calcium Ion ◽  
Calcium Ion Concentration

Animals require rapid, long-range molecular signaling networks to integrate sensing and response throughout their bodies. The amino acid glutamate acts as an excitatory neurotransmitter in the vertebrate central nervous system, facilitating long-range information exchange via activation of glutamate receptor channels. Similarly, plants sense local signals, such as herbivore attack, and transmit this information throughout the plant body to rapidly activate defense responses in undamaged parts. Here we show that glutamate is a wound signal in plants. Ion channels of the GLUTAMATE RECEPTOR–LIKE family act as sensors that convert this signal into an increase in intracellular calcium ion concentration that propagates to distant organs, where defense responses are then induced.

scholarly journals A peroxisomal β-oxidative pathway contributes to the formation of C6–C1 aromatic volatiles in poplar

2021 ◽  
Author(s):  
Nathalie D Lackus ◽  
Axel Schmidt ◽  
Jonathan Gershenzon ◽  
Tobias G Köllner
Keyword(s):  
Cinnamic Acid ◽  
Aromatic Compounds ◽  
Populus Trichocarpa ◽  
Alternative Pathway ◽  
Gene Families ◽  
Defense Responses ◽  
In Planta ◽  
Black Cottonwood ◽  
Oxidative Pathway

AbstractBenzenoids (C6–C1 aromatic compounds) play important roles in plant defense and are often produced upon herbivory. Black cottonwood (Populus trichocarpa) produces a variety of volatile and nonvolatile benzenoids involved in various defense responses. However, their biosynthesis in poplar is mainly unresolved. We showed feeding of the poplar leaf beetle (Chrysomela populi) on P. trichocarpa leaves led to increased emission of the benzenoid volatiles benzaldehyde, benzylalcohol, and benzyl benzoate. The accumulation of salicinoids, a group of nonvolatile phenolic defense glycosides composed in part of benzenoid units, was hardly affected by beetle herbivory. In planta labeling experiments revealed that volatile and nonvolatile poplar benzenoids are produced from cinnamic acid (C6–C3). The biosynthesis of C6–C1 aromatic compounds from cinnamic acid has been described in petunia (Petunia hybrida) flowers where the pathway includes a peroxisomal-localized chain shortening sequence, involving cinnamate-CoA ligase (CNL), cinnamoyl-CoA hydratase/dehydrogenase (CHD), and 3-ketoacyl-CoA thiolase (KAT). Sequence and phylogenetic analysis enabled the identification of small CNL, CHD, and KAT gene families in P. trichocarpa. Heterologous expression of the candidate genes in Escherichia coli and characterization of purified proteins in vitro revealed enzymatic activities similar to those described in petunia flowers. RNA interference-mediated knockdown of the CNL subfamily in gray poplar (Populus x canescens) resulted in decreased emission of C6–C1 aromatic volatiles upon herbivory, while constitutively accumulating salicinoids were not affected. This indicates the peroxisomal β-oxidative pathway participates in the formation of volatile benzenoids. The chain shortening steps for salicinoids, however, likely employ an alternative pathway.

scholarly journals Action potentials induce biomagnetic fields in carnivorous Venus flytrap plants

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Anne Fabricant ◽  
Geoffrey Z. Iwata ◽  
Sönke Scherzer ◽  
Lykourgos Bougas ◽  
Katharina Rolfs ◽  
...  
Keyword(s):  
Electrical Activity ◽  
Action Potentials ◽  
Plant Stress ◽  
Optically Pumped ◽  
Long Distance ◽  
Noninvasive Diagnostics ◽  
Venus Flytrap ◽  
Dionaea Muscipula ◽  
Cell Arrays ◽  
Electrical Signaling

AbstractUpon stimulation, plants elicit electrical signals that can travel within a cellular network analogous to the animal nervous system. It is well-known that in the human brain, voltage changes in certain regions result from concerted electrical activity which, in the form of action potentials (APs), travels within nerve-cell arrays. Electro- and magnetophysiological techniques like electroencephalography, magnetoencephalography, and magnetic resonance imaging are used to record this activity and to diagnose disorders. Here we demonstrate that APs in a multicellular plant system produce measurable magnetic fields. Using atomic optically pumped magnetometers, biomagnetism associated with electrical activity in the carnivorous Venus flytrap, Dionaea muscipula, was recorded. Action potentials were induced by heat stimulation and detected both electrically and magnetically. Furthermore, the thermal properties of ion channels underlying the AP were studied. Beyond proof of principle, our findings pave the way to understanding the molecular basis of biomagnetism in living plants. In the future, magnetometry may be used to study long-distance electrical signaling in a variety of plant species, and to develop noninvasive diagnostics of plant stress and disease.

scholarly journals The Effect of Fusarium verticillioides Fumonisins on Fatty Acids, Sphingolipids, and Oxylipins in Maize Germlings

2021 ◽  
Vol 22 (5) ◽  
pp. 2435
Author(s):  
Marzia Beccaccioli ◽  
Manuel Salustri ◽  
Valeria Scala ◽  
Matteo Ludovici ◽  
Andrea Cacciotti ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fusarium Verticillioides ◽  
Fungal Growth ◽  
Defense Responses ◽  
Ceramide Synthase ◽  
Ear Rot ◽  
In Planta ◽  
Disease Symptoms ◽  
The Impact

Fusarium verticillioides causes multiple diseases of Zea mays (maize) including ear and seedling rots, contaminates seeds and seed products worldwide with toxic chemicals called fumonisins. The role of fumonisins in disease is unclear because, although they are not required for ear rot, they are required for seedling diseases. Disease symptoms may be due to the ability of fumonisins to inhibit ceramide synthase activity, the expected cause of lipids (fatty acids, oxylipins, and sphingolipids) alteration in infected plants. In this study, we explored the impact of fumonisins on fatty acid, oxylipin, and sphingolipid levels in planta and how these changes affect F. verticillioides growth in maize. The identity and levels of principal fatty acids, oxylipins, and over 50 sphingolipids were evaluated by chromatography followed by mass spectrometry in maize infected with an F. verticillioides fumonisin-producing wild-type strain and a fumonisin-deficient mutant, after different periods of growth. Plant hormones associated with defense responses, i.e., salicylic and jasmonic acid, were also evaluated. We suggest that fumonisins produced by F. verticillioides alter maize lipid metabolism, which help switch fungal growth from a relatively harmless endophyte to a destructive necrotroph.

scholarly journals Aboveground Herbivory Influences Belowground Defense Responses in Maize

2021 ◽  
Vol 9 ◽  
Author(s):  
Lise Pingault ◽  
Saumik Basu ◽  
Prince Zogli ◽  
W. Paul Williams ◽  
Nathan Palmer ◽  
...  
Keyword(s):  
European Corn Borer ◽  
Proteinase Inhibitors ◽  
Insect Pest ◽  
Diabrotica Virgifera Virgifera ◽  
Defense Responses ◽  
Short Term ◽  
Long Distance ◽  
Corn Borer ◽  
Root Physiology ◽  
Aboveground Herbivory

The European corn borer (ECB; Ostrinia nubilalis) is an economically damaging insect pest of maize (Zea mays L.), an important cereal crop widely grown globally. Among inbred lines, the maize genotype Mp708 has shown resistance to diverse herbivorous insects, although several aspects of the defense mechanisms of Mp708 plants are yet to be explored. Here, the changes in root physiology arising from short-term feeding by ECB on the shoot tissues of Mp708 plants was evaluated directly using transcriptomics, and indirectly by monitoring changes in growth of western corn rootworm (WCR; Diabrotica virgifera virgifera) larvae. Mp708 defense responses negatively impacted both ECB and WCR larval weights, providing evidence for changes in root physiology in response to ECB feeding on shoot tissues. There was a significant downregulation of genes in the root tissues following short-term ECB feeding, including genes needed for direct defense (e.g., proteinase inhibitors and chitinases). Our transcriptomic analysis also revealed specific regulation of the genes involved in hormonal and metabolite pathways in the roots of Mp708 plants subjected to ECB herbivory. These data provide support for the long-distance signaling-mediated defense in Mp708 plants and suggest that altered metabolite profiles of roots in response to ECB feeding of shoots likely negatively impacted WCR growth.

scholarly journals Molecular Insights into Defense Responses of Vietnamese Maize Varieties to Fusarium verticillioides Isolates

2021 ◽  
Vol 7 (9) ◽  
pp. 724
Author(s):  
Trang Minh Tran ◽  
Maarten Ameye ◽  
Sofie Landschoot ◽  
Frank Devlieghere ◽  
Sarah De Saeger ◽  
...  
Keyword(s):  
Expression Profiles ◽  
Fusarium Verticillioides ◽  
Gene Expression Profiles ◽  
Defense Responses ◽  
Ear Rot ◽  
In Planta ◽  
Resistant Lines ◽  
Maize Varieties ◽  
Pathogenesis Related ◽  
Related Proteins

Fusarium ear rot (FER) caused by Fusarium verticillioides is one of the main fungal diseases in maize worldwide. To develop a pathogen-tailored FER resistant maize line for local implementation, insights into the virulence variability of a residing F. verticillioides population are crucial for developing customized maize varieties, but remain unexplored. Moreover, little information is currently available on the involvement of the archetypal defense pathways in the F. verticillioides–maize interaction using local isolates and germplasm, respectively. Therefore, this study aims to fill these knowledge gaps. We used a collection of 12 F. verticillioides isolates randomly gathered from diseased maize fields in the Vietnamese central highlands. To assess the plant’s defense responses against the pathogens, two of the most important maize hybrid genotypes grown in this agro-ecological zone, lines CP888 and Bt/GT NK7328, were used. Based on two assays, a germination and an in-planta assay, we found that line CP888 was more susceptible to the F. verticillioides isolates when compared to line Bt/GT NK7328. Using the most aggressive isolate, we monitored disease severity and gene expression profiles related to biosynthesis pathways of salicylic acid (SA), jasmonic acid (JA), abscisic acid (ABA), benzoxazinoids (BXs), and pathogenesis-related proteins (PRs). As a result, a stronger induction of SA, JA, ABA, BXs, and PRs synthesizing genes might be linked to the higher resistance of line Bt/GT NK7328 compared to the susceptible line CP888. All these findings could supply valuable knowledge in the selection of suitable FER resistant lines against the local F. verticllioides population and in the development of new FER resistant germplasms.

Demethylation of genes in animal cells

1990 ◽  
Vol 326 (1235) ◽  
pp. 241-251 ◽  
Keyword(s):  
Tissue Culture ◽  
Germ Line ◽  
Animal Cell ◽  
Gene Activation ◽  
Housekeeping Gene ◽  
Cell Types ◽  
Embryonic Cells ◽  
Animal Cells ◽  
Developmentally Regulated ◽  
I Gene

Tissue-specific animal cell genes are usually fully methylated in the germ line and become demethylated in those cell types in which they are expressed. To investigate this process, we inserted a methylated IgG K gene into fibroblasts and lymphocytes at various stages of development. The results show that this gene undergoes demethylation only in the mature lymphocytes and therefore suggest that the ability to demethylate a gene is developmentally regulated. These studies were supported by similar experiments using the rat Insulin I gene, and in this case it appears that the cis -acting elements that control demethylation may be different from those responsible for gene activation. The ability to demethylate the housekeeping gene APRT is also under developmental control, because this occurs only in embryonic cells, both in tissue culture and in transgenic mice.

scholarly journals Global Gene Expression Profiles Suggest an Important Role for Nutrient Acquisition in Early Pathogenesis in a Plant Model of Pseudomonas aeruginosa Infection

2008 ◽  
Vol 74 (18) ◽  
pp. 5784-5791 ◽  
Author(s):  
Tiffany L. Weir ◽  
Valerie J. Stull ◽  
Dayakar Badri ◽  
Lily A. Trunck ◽  
Herbert P. Schweizer ◽  
...  
Keyword(s):  
Gene Expression ◽  
Pseudomonas Aeruginosa ◽  
Salicylic Acid ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Global Gene Expression ◽  
Defense Responses ◽  
N Gene ◽  
Virulence Determinants ◽  
In Planta

ABSTRACT Although Pseudomonas aeruginosa is an opportunistic pathogen that does not often naturally infect alternate hosts, such as plants, the plant-P. aeruginosa model has become a widely recognized system for identifying new virulence determinants and studying the pathogenesis of the organism. Here, we examine how both host factors and P. aeruginosa PAO1 gene expression are affected in planta after infiltration into incompatible and compatible cultivars of tobacco (Nicotiana tabacum L.). N. tabacum has a resistance gene (N) against tobacco mosaic virus, and although resistance to PAO1 infection is correlated with the presence of a dominant N gene, our data suggest that it is not a factor in resistance against PAO1. We did observe that the resistant tobacco cultivar had higher basal levels of salicylic acid and a stronger salicylic acid response upon infiltration of PAO1. Salicylic acid acts as a signal to activate defense responses in plants, limiting the spread of the pathogen and preventing access to nutrients. It has also been shown to have direct virulence-modulating effects on P. aeruginosa. We also examined host effects on the pathogen by analyzing global gene expression profiles of bacteria removed from the intracellular fluid of the two plant hosts. We discovered that the availability of micronutrients, particularly sulfate and phosphates, is important for in planta pathogenesis and that the amounts of these nutrients made available to the bacteria may in turn have an effect on virulence gene expression. Indeed, there are several reports suggesting that P. aeruginosa virulence is influenced in mammalian hosts by the availability of micronutrients, such as iron and nitrogen, and by levels of O2.

scholarly journals Cytological Characterization of Elicitin-Induced Protection in Tobacco Plants Infected by Phytophthora parasitica or Phytoplasma

2003 ◽  
Vol 93 (10) ◽  
pp. 1308-1319 ◽  
Author(s):  
J. Lherminier ◽  
N. Benhamou ◽  
J. Larrue ◽  
M.-L. Milat ◽  
E. Boudon-Padieu ◽  
...  
Keyword(s):  
Defense Responses ◽  
Phytophthora Parasitica ◽  
In Planta ◽  
Intercellular Spaces ◽  
Tobacco Plants ◽  
Sieve Elements ◽  
Small Proteins ◽  
Physical Barriers ◽  
Wall Appositions ◽  
P Proteins

Elicitins, small proteins secreted by Phytophthora and Pythium spp., display the ability to induce plant resistance toward pathogens. Ultrastructural investigations of cryptogein-treated tobacco plants evidenced host defense responses such as (i) formation of a calcium pectate gel in intercellular spaces of parenchymas, (ii) impregnation of pectin by phenolic compounds in intercellular spaces of phloem bundles, and (iii) accumulation of phloem proteins (P proteins) in the lumen of leaf sieve elements. These cytological modifications lead to the enhancement of physical barriers that prevent pathogen ingress and restrict host tissue colonization when cryptogein-treated tobacco plants were challenged with the pathogen Phytophthora parasitica. Wall appositions also were observed at most sites of penetration of hyphae. Moreover, growing hyphae exhibited severe morphological damages, suggesting a modified toxic environment. The same induction of P proteins in mature sieve tubes of tobacco leaves was obtained with oligandrin treatment, another elicitin. Cryptogein or oligandrin treatment prevented symptom expression in phytoplasma-infected tobacco plants in contrast with nontreated tobacco plants. Moreover, P protein plugs and occlusion of pore sites by callose were evidenced in sieve elements of treated plants. Both these phloem modifications might prevent the in planta movement of phloem-restricted microorganisms.

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