scholarly journals CML8 and GAD4 function in (Z)–3–hexenol–mediated defense by regulating GABA accumulation in Arabidopsis

2021 ◽  
Author(s):  
Chunyang Jiao ◽  
zhujuan Guo ◽  
Shuwen Li ◽  
Yixin Zuo ◽  
Junqing Gong ◽  
...  
Keyword(s):  
Calcium Content ◽  
Firefly Luciferase ◽  
Defense Responses ◽  
Control Measures ◽  
Calcium Stores ◽  
Mesophyll Cells ◽  
Intracellular Content ◽  
Insect Defense ◽  
Gaba Accumulation ◽  
Two Hybrid

(Z)–3–hexenol, a small gaseous molecule, is produced in plants under biotic stress and induces defense responses in neighboring plants. However, the research on little is known about how (Z)–3–hexenol induces plant defense–related signaling. In this study, we uncovered how (Z)–3–hexenol treatment enhances insect resistance by increasing γ–aminobutyric acid (GABA) contents in Arabidopsis thaliana leaves. First, (Z)–3–hexenol increases the intracellular content of the signaling molecule calcium in Arabidopsis leaf mesophyll cells. Both intracellular and extracellular calcium stores regulate these changes in calcium content. Then, CML8 and GAD4 are involved in calcium signaling. Yeast two–hybrid assays, firefly luciferase complementation imaging, and GST pull–down assays demonstrated that CML8 interacts with GAD4. Finally, (Z)–3–hexenol treatment increased the GABA contents in Arabidopsis leaves, thus increasing plant resistance to the insect Plutella xylostella. This study revealed the mechanism of activating plant insect defense induced by (Z)–3–hexenol, which is of great significance for the study of volatiles as biological control measures.

scholarly journals Structure and functions of plant calcium-dependent protein kinases.

2007 ◽  
Vol 54 (2) ◽  
pp. 219-233 ◽  
Author(s):  
Maria Klimecka ◽  
Grazyna Muszyńska
Keyword(s):  
Protein Kinases ◽  
Calcium Ions ◽  
Second Messengers ◽  
Calcium Content ◽  
Defense Responses ◽  
Calcium Dependent ◽  
Cytoskeleton Organization ◽  
Calcium Sensors ◽  
Dependent Protein ◽  
Calcium Dependent Protein Kinases

Calcium ions as second messengers play an essential role in many important cellular processes. In plants, transient changes in calcium content in the cytosol (calcium signatures) have been observed during growth, development and under stress conditions. Such diverse functions require many different calcium sensors. One of the largest and most differentiated group of calcium sensors are protein kinases, among them calcium-dependent protein kinases (CDPKs) which were identified only in plants and protists. CDPKs have a regulatory domain which is able to bind calcium ions. For regulation of CDPKs activities not only calcium ions but also specific phospholipids and autophosphorylation are responsible. CDPKs have many different substrates, which reflects the diversity of their functions. Potential protein substrates of CDPK are involved in carbon and nitrogen metabolism, phospholipid synthesis, defense responses, ion and water transport, cytoskeleton organization, transcription and hormone responses. Presently, participation of CDPKs in stress signal transduction pathways (e.g., cold, drought, high salinity, wounding) is intensively studied in many laboratories. An intriguing, but still not fully clarified problem is the cross-talk via CDPKs among different signaling pathways that enables signal integration at different levels and ensure appropriate downstream responses.

scholarly journals Expression of Putative Defense Responses in Cannabis Primed by Pseudomonas and/or Bacillus Strains and Infected by Botrytis cinerea

2020 ◽  
Vol 11 ◽  
Author(s):  
Carole Balthazar ◽  
Gabrielle Cantin ◽  
Amy Novinscak ◽  
David L. Joly ◽  
Martin Filion
Keyword(s):  
Botrytis Cinerea ◽  
Cannabis Sativa ◽  
Molecular Level ◽  
Quantitative Polymerase Chain Reaction ◽  
Defense Responses ◽  
Gray Mold ◽  
Control Measures ◽  
Effective Control ◽  
Defense Genes ◽  
Polymerase Chain

Cannabis (Cannabis sativa L.) offers many industrial, agricultural, and medicinal applications, but is commonly threatened by the gray mold disease caused by the fungus Botrytis cinerea. With few effective control measures currently available, the use of beneficial rhizobacteria represents a promising biocontrol avenue for cannabis. To counter disease development, plants rely on a complex network of inducible defense pathways, allowing them to respond locally and systemically to pathogens attacks. In this study, we present the first attempt to control gray mold in cannabis using beneficial rhizobacteria, and the first investigation of cannabis defense responses at the molecular level. Four promising Pseudomonas (LBUM223 and WCS417r) and Bacillus strains (LBUM279 and LBUM979) were applied as single or combined root treatments to cannabis seedlings, which were subsequently infected by B. cinerea. Symptoms were recorded and the expression of eight putative defense genes was monitored in leaves by reverse transcription quantitative polymerase chain reaction. The rhizobacteria did not significantly control gray mold and all infected leaves were necrotic after a week, regardless of the treatment. Similarly, no systemic activation of putative cannabis defense genes was reported, neither triggered by the pathogen nor by the rhizobacteria. However, this work identified five putative defense genes (ERF1, HEL, PAL, PR1, and PR2) that were strongly and sustainably induced locally at B. cinerea’s infection sites, as well as two stably expressed reference genes (TIP41 and APT1) in cannabis. These markers will be useful in future researches exploring cannabis defense pathways.

scholarly journals CmMLO17 and its partner CmKIC potentially support Alternaria alternata growth in Chrysanthemum morifolium

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Jingjing Xin ◽  
Ye Liu ◽  
Huiyun Li ◽  
Sumei Chen ◽  
Jiafu Jiang ◽  
...  
Keyword(s):  
Signaling Pathways ◽  
Alternaria Alternata ◽  
Defense Responses ◽  
Chrysanthemum Morifolium ◽  
Bimolecular Fluorescence Complementation ◽  
Resistance Locus ◽  
Plant Defense Responses ◽  
Yeast Two Hybrid ◽  
Two Hybrid ◽  
Insight Into

AbstractThe Mildew Resistance Locus O (MLO) gene family has been investigated in many species. However, there are few studies on chrysanthemum MLO genes. We report in this study that CmMLO17 in Chrysanthemum morifolium was upregulated after Alternaria alternata infection. Silencing of CmMLO17 by artificial microRNA resulted in reduced susceptibility of chrysanthemum to A. alternata infection. Genes in the abscisic acid (ABA) and Ca2+ signaling pathways were upregulated in the CmMLO17-silenced line R20 compared to the wild-type plants. We speculated that CmMLO17-silenced plants had a faster and stronger defense response that was mediated by the ABA and Ca2+ signaling pathways, resulting in reduced susceptibility of chrysanthemum to A. alternata infection. In addition, a candidate gene, CmKIC, that may interact with CmMLO17 was discovered by the yeast two-hybrid assay. The interaction between CmMLO17 and CmKIC was confirmed using the yeast two-hybrid assay and bimolecular fluorescence complementation (BiFC) analysis. CmMLO17 and CmKIC were both located on the plasma membrane, and CmKIC was also located on the nucleus. CmKIC overexpression increased the susceptibility of chrysanthemum to A. alternata, whereas CmKIC silencing resulted in reduced susceptibility. Therefore, CmMLO17 and CmKIC may work together in C. morifolium to support the growth of A. alternata. The results of this study will provide insight into the potential function of MLO and improve the understanding of plant defense responses to necrotrophic pathogens.

scholarly journals An Immuno-Suppressive Aphid Saliva Protein Is Delivered into the Cytosol of Plant Mesophyll Cells During Feeding

2016 ◽  
Vol 29 (11) ◽  
pp. 854-861 ◽  
Author(s):  
Sam T. Mugford ◽  
Elaine Barclay ◽  
Claire Drurey ◽  
Kim C. Findlay ◽  
Saskia A. Hogenhout
Keyword(s):  
Plant Defense ◽  
Plant Cells ◽  
Defense Responses ◽  
Plant Responses ◽  
Plant Defense Responses ◽  
Mesophyll Cells ◽  
Virulence Proteins ◽  
Feeding Sites ◽  
Ultrathin Sections ◽  
Aphid Feeding

Herbivore selection of plant hosts and plant responses to insect colonization have been subjects of intense investigations. A growing body of evidence suggests that, for successful colonization to occur, (effector/virulence) proteins in insect saliva must modulate plant defense responses to the benefit of the insect. A range of insect saliva proteins that modulate plant defense responses have been identified, but there is no direct evidence that these proteins are delivered into specific plant tissues and enter plant cells. Aphids and other sap-sucking insects of the order Hemiptera use their specialized mouthparts (stylets) to probe plant mesophyll cells until they reach the phloem cells for long-term feeding. Here, we show, by immunogold-labeling of ultrathin sections of aphid feeding sites, that an immuno-suppressive aphid effector localizes in the cytoplasm of mesophyll cells near aphid stylets but not in cells further away from aphid feeding sites. In contrast, another aphid effector protein localizes in the sheaths composed of gelling saliva that surround the aphid stylets. Thus, insects deliver effectors directly into plant tissue. Moreover, different aphid effectors locate extracellularly in the sheath saliva or are introduced into the cytoplasm of plant cells. [Formula: see text] Copyright © 2016 The Author(s). This is an open-access article distributed under the CC BY-NC-ND 4.0 International license .

scholarly journals SEVEN IN ABSENTIA Ubiquitin Ligases Positively Regulate Defense Against Verticillium dahliae in Gossypium hirsutum

2021 ◽  
Vol 12 ◽  
Author(s):  
Zhongying Ren ◽  
Wei Liu ◽  
Xingxing Wang ◽  
Mingjiang Chen ◽  
Junjie Zhao ◽  
...  
Keyword(s):  
Gossypium Hirsutum ◽  
Verticillium Dahliae ◽  
Ubiquitin Ligases ◽  
Defense Responses ◽  
Yeast Two Hybrid ◽  
E3 Ligases ◽  
Positive Regulators ◽  
Seven In Absentia ◽  
Two Hybrid

Ubiquitination is a post-translational regulatory mechanism that controls a variety of biological processes in plants. The E3 ligases confer specificity by recognizing target proteins for ubiquitination. Here, we identified SEVEN IN ABSENTIA (SINA) ubiquitin ligases, which belong to the RING-type E3 ligase family, in upland cotton (Gossypium hirsutum). Twenty-four GhSINAs were characterized, and the expression levels of GhSINA7, GhSINA8, and GhSINA9 were upregulated at 24 h after inoculation with Verticillium dahliae. In vitro ubiquitination assays indicated that the three GhSINAs possessed E3 ubiquitin ligase activities. Transient expression in Nicotiana benthamiana leaves showed that they localized to the nucleus. And yeast two-hybrid (Y2H) screening revealed that they could interact with each other. The ectopic overexpression of GhSINA7, GhSINA8, and GhSINA9 independently in Arabidopsis thaliana resulted in increased tolerance to V. dahliae, while individual knockdowns of GhSINA7, GhSINA8, and GhSINA9 compromised cotton resistance to the pathogen. Thus, GhSINA7, GhSINA8, and GhSINA9 act as positive regulators of defense responses against V. dahliae in cotton plants.

scholarly journals Escherichia coli O157:H7 Induces Stronger Plant Immunity than Salmonella enterica Typhimurium SL1344

2013 ◽  
Vol 103 (4) ◽  
pp. 326-332 ◽  
Author(s):  
Debanjana Roy ◽  
Shweta Panchal ◽  
Bruce A. Rosa ◽  
Maeli Melotto
Keyword(s):  
Escherichia Coli ◽  
Salmonella Enterica ◽  
Pathogenic Bacteria ◽  
Plant Immunity ◽  
Stomatal Closure ◽  
Defense Responses ◽  
Control Measures ◽  
Escherichia Coli O157 ◽  
Human Pathogens ◽  
Field And Laboratory Conditions

Consumption of fresh produce contaminated with bacterial human pathogens has resulted in various, sometimes deadly, disease outbreaks. In this study, we assessed plant defense responses induced by the fully pathogenic bacteria Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium SL1344 in both Arabidopsis thaliana and lettuce (Lactuca sativa). Unlike SL1344, O157:H7 induced strong plant immunity at both pre-invasion and post-invasion steps of infection. For instance, O157:H7 triggered stomatal closure even under high relative humidity, an environmental condition that generally weakens plant defenses against bacteria in the field and laboratory conditions. SL1344 instead induced a transient stomatal immunity. We also observed that PR1 gene expression was significantly higher in Arabidopsis leaves infected with O157:H7 compared with SL1344. These results suggest that plants may recognize and respond to some human pathogens more effectively than others. Furthermore, stomatal immunity can diminish the penetration of human pathogens through the leaf epidermis, resulting in low bacterial titers in the plant apoplast and suggesting that additional control measures can be employed to prevent food contamination. The understanding of how plant responses can diminish bacterial contamination is paramount in preventing outbreaks and improving the safety of food supplies.

scholarly journals Evidence for Systemic Infection by Puccinia horiana, Causal Agent of Chrysanthemum White Rust, in Chrysanthemum

2015 ◽  
Vol 105 (1) ◽  
pp. 91-98 ◽  
Author(s):  
M. R. Bonde ◽  
C. A. Murphy ◽  
G. R. Bauchan ◽  
D. G. Luster ◽  
C. L. Palmer ◽  
...  
Keyword(s):  
United States ◽  
Cell Walls ◽  
Vascular Tissue ◽  
Mesophyll Cell ◽  
The United States ◽  
Causal Agent ◽  
Control Measures ◽  
Mesophyll Cells ◽  
White Rust ◽  
Puccinia Horiana

Puccinia horiana, causal agent of the disease commonly known as chrysanthemum white rust (CWR), is a quarantine-significant fungal pathogen of chrysanthemum in the United States and indigenous to Asia. The pathogen was believed to have been eradicated in the United States but recently reappeared on several occasions in northeastern United States. The objective of the study presented here was to determine whether P. horiana could systemically infect chrysanthemum plants, thus providing a means of survival through winters. Scanning and transmission electron microscopy revealed the development of P. horiana on the surface and within leaves, stems, or crowns of inoculated chrysanthemum plants artificially exposed to northeastern U.S. winter temperatures. P. horiana penetrated leaves directly through the cuticle and then colonized the mesophyll tissue both inter- and intracellularly. An electron-dense material formed at the interface between fungal and host mesophyll cells, suggesting that the pathogen adhered to the plant cells. P. horiana appeared to penetrate mesophyll cell walls by enzymatic digestion, as indicated by the absence of deformation lines in host cell walls at penetration sites. The fungus was common in vascular tissue within the infected crown, often nearly replacing the entire contents of tracheid cell walls. P. horiana frequently passed from one tracheid cell to an adjacent tracheid cell by penetration either through pit pairs or nonpitted areas of the cell walls. Individual, presumed, fungal cells in mature tracheid cells of the crown and stems arising from infected crowns suggested that the pathogen might have been moving at least partially by means of the transpiration stream. The demonstration that chrysanthemum plants can be systemically infected by P. horiana suggests that additional disease control measures are required to effectively control CWR.

Ptr ToxA Interacts with a Chloroplast-Localized Protein

2007 ◽  
Vol 20 (2) ◽  
pp. 168-177 ◽  
Author(s):  
Viola A. Manning ◽  
Linda K. Hardison ◽  
Lynda M. Ciuffetti
Keyword(s):  
Coiled Coil ◽  
Tan Spot ◽  
Yeast Two Hybrid ◽  
Mesophyll Cells ◽  
Pyrenophora Tritici Repentis ◽  
Ptr Toxa ◽  
Coiled Coil Domain ◽  
Multimeric Complex ◽  
Chloroplast Stroma ◽  
Two Hybrid

Pyrenophora tritici-repentis, causal agent of tan spot of wheat, produces host-selective toxins that are determinants of pathogenicity or virulence. Ptr ToxA (ToxA), a proteina-ceous toxin produced by P. tritici-repentis, is a necrotizing toxin produced by the most common races isolated from infected wheat. Recent studies have shown that ToxA is internalized into the mesophyll cells and localizes to chloroplasts of sensitive wheat cultivars only. We employed a yeast two-hybrid screen in an effort to determine plant proteins that interact with ToxA and found that ToxA interacts with a chloroplast protein, designated ToxA binding protein 1 (ToxABP1). ToxABP1 contains a lysine-rich region within a coiled-coil domain that is similar to phosphotidyl-inositol binding sites present in animal proteins involved in endocytosis. In both ToxA-sensitive and -insensitive cultivars, ToxABP1 is expressed at similar levels and encodes an identical protein. ToxABP1 protein is present in both chloroplast membranes and chloroplast stroma. ToxA appears to interact primarily with a multimeric complex of ToxABP1 protein associated with the chloroplast membrane.

scholarly journals Role of Ryanodine Receptor Subtypes in Initiation and Formation of Calcium Sparks in Arterial Smooth Muscle: Comparison with Striated Muscle

2009 ◽  
Vol 2009 ◽  
pp. 1-15 ◽  
Author(s):  
Kirill Essin ◽  
Maik Gollasch
Keyword(s):  
Smooth Muscle ◽  
Calcium Release ◽  
Striated Muscle ◽  
Ryanodine Receptors ◽  
Calcium Content ◽  
Receptor Subtypes ◽  
Calcium Stores ◽  
Calcium Sparks ◽  
Arterial Smooth Muscle

Calcium sparks represent local, rapid, and transient calcium release events from a cluster of ryanodine receptors (RyRs) in the sarcoplasmic reticulum. In arterial smooth muscle cells (SMCs), calcium sparks activate calcium-dependent potassium channels causing decrease in the global intracellular[Ca2+]and oppose vasoconstriction. This is in contrast to cardiac and skeletal muscle, where spatial and temporal summation of calcium sparks leads to global increases in intracellular[Ca2+]and myocyte contraction. We summarize the present data on local RyR calcium signaling in arterial SMCs in comparison to striated muscle and muscle-specific differences in coupling between L-type calcium channels and RyRs. Accordingly, arterial SMCCav1.2L-type channels regulate intracellular calcium stores content, which in turn modulates calcium efflux though RyRs. Downregulation of RyR2 up to a certain degree is compensated by increased SR calcium content to normalize calcium sparks. This indirect coupling betweenCav1.2and RyR in arterial SMCs is opposite to striated muscle, where triggering of calcium sparks is controlled by rapid and direct cross-talk betweenCav1.1/Cav1.2L-type channels and RyRs. We discuss the role of RyR isoforms in initiation and formation of calcium sparks in SMCs and their possible molecular binding partners and regulators, which differ compared to striated muscle.

Cytosolic acidification and γ-aminobutyric acid synthesis during the oxidative burst in isolated Asparagus sprengeri mesophyll cells

2001 ◽  
Vol 79 (4) ◽  
pp. 438-443
Author(s):  
David J Janzen ◽  
Lisa J Allen ◽  
Kennaway B MacGregor ◽  
Alan W Bown
Keyword(s):  
Oxidative Burst ◽  
Acid Synthesis ◽  
Aminobutyric Acid ◽  
Intracellular Acidification ◽  
Protein Amino Acid ◽  
Mesophyll Cells ◽  
Intracellular Ca ◽  
Gaba Accumulation ◽  
Gaba Synthesis ◽  
The Relationship

The four carbon, non-protein amino acid γ-aminobutyrate (GABA) accumulates rapidly in response to diverse stresses. Its synthesis is stimulated by increases in intracellular Ca2+ or H+ levels. The pathogen-induced oxidative burst is also associated with increases in Ca2+ and H+ levels. This study investigated the relationship between GABA synthesis and the oxidative burst. A Mas-7-induced consumption of oxygen in isolated Asparagus sprengeri Regel mesophyll cells was accompanied by rapid GABA synthesis. At pH 5.0, a 300% increase occurred within 16 min from 6.6 to 26.3 nmol GABA·106 cells–1. At pH 6.0, the increase was from 8.5 to 18.1 nmol GABA·106 cells–1. Mas-7 also stimulated rapid external alkalinization and intracellular acidification. Intracellular pH decreased 0.44 pH units at pH 5.0, and 0.21 pH units at pH 6.0. The Mas-7-induced oxidative burst, GABA synthesis, extracellular alkalinization, and intracellular acidification were all eliminated when lanthanum, a Ca2+ channel blocker, replaced Ca2+ in the incubation medium. The data demonstrate that GABA accumulation is associated with the oxidative burst, and results from the fluxes of H+ and Ca2+, which are known to accompany the oxidative burst. They are discussed in light of emerging data that indicate a role for GABA in plant cell to cell signaling.Key words: γ-aminobutyric acid, GABA, oxidative burst.

Sign in / Sign up

Export Citation Format

Share Document