scholarly journals Activation of Local and Systemic Defence Responses by Flg22 Is Dependent on Daytime and Ethylene in Intact Tomato Plants

2021 ◽  
Vol 22 (15) ◽  
pp. 8354
Author(s):  
Zalán Czékus ◽  
András Kukri ◽  
Kamirán Áron Hamow ◽  
Gabriella Szalai ◽  
Irma Tari ◽  
...  
Keyword(s):  
Stomatal Closure ◽  
Plant Defence ◽  
Time Of Day ◽  
Light Period ◽  
Ethylene Response Factor ◽  
Wild Type ◽  
Tomato Plants ◽  
Production Of Hydrogen ◽  
Pathogenesis Related ◽  
Defence Responses

The first line of plant defence responses against pathogens can be induced by the bacterial flg22 and can be dependent on various external and internal factors. Here, we firstly studied the effects of daytime and ethylene (ET) using Never ripe (Nr) mutants in the local and systemic defence responses of intact tomato plants after flg22 treatments. Flg22 was applied in the afternoon and at night and rapid reactions were detected. The production of hydrogen peroxide and nitric oxide was induced by flg22 locally, while superoxide was induced systemically, in wild type plants in the light period, but all remained lower at night and in Nr leaves. Flg22 elevated, locally, the ET, jasmonic acid (JA) and salicylic acid (SA) levels in the light period; these levels did not change significantly at night. Expression of Pathogenesis-related 1 (PR1), Ethylene response factor 1 (ERF1) and Defensin (DEF) showed also daytime- and ET-dependent changes. Enhanced ERF1 and DEF expression and stomatal closure were also observable in systemic leaves of wild type plants in the light. These data demonstrate that early biotic signalling in flg22-treated leaves and distal ones is an ET-dependent process and it is also determined by the time of day and inhibited in the early night phase.

scholarly journals Effects of Light and Daytime on the Regulation of Chitosan-Induced Stomatal Responses and Defence in Tomato Plants

Plants ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 59 ◽  
Author(s):  
Zalán Czékus ◽  
Péter Poór ◽  
Irma Tari ◽  
Attila Ördög
Keyword(s):  
Stomatal Closure ◽  
Plant Defence ◽  
Guard Cells ◽  
Ethylene Response Factor ◽  
Mesophyll Cells ◽  
Dark Light ◽  
Tomato Plants ◽  
Pathogenesis Related ◽  
Defence Responses ◽  
Plant Defence Responses

Closure of stomata upon pathogenesis is among the earliest plant immune responses. However, our knowledge is very limited about the dependency of plant defence responses to chitosan (CHT) on external factors (e.g., time of the day, presence, or absence of light) in intact plants. CHT induced stomatal closure before dark/light transition in leaves treated at 17:00 hrs and stomata were closed at 09:00 hrs in plants treated at dawn and in the morning. CHT was able to induce generation of reactive oxygen species (ROS) in guard cells in the first part of the light phase, but significant nitric oxide production was observable only at 15:00 hrs. The actual quantum yield of PSII electron transport (ΦPSII) decreased upon CHT treatments at 09:00 hrs in guard cells but it declined only at dawn in mesophyll cells after the treatment at 17:00 hrs. Expression of Pathogenesis-related 1 (PR1) and Ethylene Response Factor 1 were already increased at dawn in the CHT-treated leaves but PR1 expression was inhibited in the dark. CHT-induced systemic response was also observed in the distal leaves of CHT-treated ones. Our results suggest a delayed and daytime-dependent defence response of tomato plants after CHT treatment at night and under darkness.

scholarly journals Zinc phosphate protects tomato plants against Pseudomonas syringae pv. tomato

2021 ◽  
Author(s):  
Mara Quaglia ◽  
Marika Bocchini ◽  
Benedetta Orfei ◽  
Roberto D’Amato ◽  
Franco Famiani ◽  
...  
Keyword(s):  
Disease Severity ◽  
Pseudomonas Syringae ◽  
Zinc Phosphate ◽  
Plant Defence ◽  
In Planta ◽  
Tomato Plants ◽  
Pathogenesis Related Protein ◽  
Defence Responses ◽  
Plant Defence Responses

AbstractThe purpose of this study was to determine whether zinc phosphate treatments of tomato plants (Solanum lycopersicum L.) can attenuate bacterial speck disease severity through reduction of Pseudomonas syringae pv. tomato (Pst) growth in planta and induce morphological and biochemical plant defence responses. Tomato plants were treated with 10 ppm (25.90 µM) zinc phosphate and then spray inoculated with strain DAPP-PG 215, race 0 of Pst. Disease symptoms were recorded as chlorosis and/or necrosis per leaf (%) and as numbers of necrotic spots. Soil treatments with zinc phosphate protected susceptible tomato plants against Pst, with reductions in both disease severity and pathogen growth in planta. The reduction of Pst growth in planta combined with significantly higher zinc levels in zinc-phosphate-treated plants indicated direct antimicrobial toxicity of this microelement, as also confirmed by in vitro assays. Morphological (i.e. callose apposition) and biochemical (i.e., expression of salicylic-acid-dependent pathogenesis-related protein PR1b1 gene) defence responses were induced by the zinc phosphate treatment, as demonstrated by histochemical and qPCR analyses, respectively. In conclusion, soil treatments with zinc phosphate can protect tomato plants against Pst attacks through direct antimicrobial activity and induction of morphological and biochemical plant defence responses.

Diverse Responses Are Involved in the Defence of Arabidopsis thaliana against Turnip Crinkle Virus

2013 ◽  
Vol 68 (3-4) ◽  
pp. 148-154 ◽  
Author(s):  
Hui Yang ◽  
Shu Yuan ◽  
Yi Luo ◽  
Ji Huang ◽  
Yang-Er Chen ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Plant Hormones ◽  
Plant Defence ◽  
Mitogen Activated Protein Kinase ◽  
Turnip Crinkle Virus ◽  
Wild Type ◽  
Antagonistic Action ◽  
Pathogenesis Related ◽  
Mitogen Activated Protein ◽  
Plant Pathogen Interactions

Plant hormones play pivotal roles as signals of plant-pathogen interactions. Here, we report that exogenous application of salicylic acid (SA), jasmonic acid (JA), ethephon (ETH), and abscisic acid (ABA) can reduce Turnip crinkle virus (TCV) accumulation in systemic leaves of Arabidopsis thaliana during early infection. SA and ABA are more efficient and confer a longer-lasting resistance against TCV than JA and ETH, and the plant hormones interact in effecting the plant defence. Synergistic actions of SA and JA, and SA and ET, and an antagonistic action of SA and ABA have been observed in the Arabidopsis-TCV interaction. ABA can down-regulate the expression of the pathogenesis-related genes PR1 and PDF1.2, and compared to the wild type, it drastically reduces TCV accumulation in NahG transgenic plants and the eds5-p1 mutant, both of which do not accumulate SA. This indicates that SA signaling negatively regulates the ABA-mediated defence. ABA-induced resistance against TCV is independent of SA. We also found that mitogen-activated protein kinase 5 (MPK5) may be involved in ABA-mediated defence. These results indicate that Arabidopsis can activate distinct signals to inhibit virus accumulation. Cooperative or antagonistic crosstalk between them is pivotal for establishing disease resistance. These results show potential to enhance the plant defence against viruses by manipulating diverse hormones.

scholarly journals Constitutive cyclic GMP accumulation in Arabidopsis thaliana compromises systemic acquired resistance induced by an avirulent pathogen by modulating local signals

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Jamshaid Hussain ◽  
Jian Chen ◽  
Vittoria Locato ◽  
Wilma Sabetta ◽  
Smrutisanjita Behera ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Large Scale ◽  
Systemic Acquired Resistance ◽  
Soluble Guanylate Cyclase ◽  
Acquired Resistance ◽  
Plant Defence ◽  
Redox System ◽  
Wild Type ◽  
Transgenic Lines ◽  
Defence Responses

Abstract The infection of Arabidopsis thaliana plants with avirulent pathogens causes the accumulation of cGMP with a biphasic profile downstream of nitric oxide signalling. However, plant enzymes that modulate cGMP levels have yet to be identified, so we generated transgenic A. thaliana plants expressing the rat soluble guanylate cyclase (GC) to increase genetically the level of cGMP and to study the function of cGMP in plant defence responses. Once confirmed that cGMP levels were higher in the GC transgenic lines than in wild-type controls, the GC transgenic plants were then challenged with bacterial pathogens and their defence responses were characterized. Although local resistance was similar in the GC transgenic and wild-type lines, differences in the redox state suggested potential cross-talk between cGMP and the glutathione redox system. Furthermore, large-scale transcriptomic and proteomic analysis highlighted the significant modulation of both gene expression and protein abundance at the infection site, inhibiting the establishment of systemic acquired resistance. Our data indicate that cGMP plays a key role in local responses controlling the induction of systemic acquired resistance in plants challenged with avirulent pathogens.

Different arbuscular mycorrhizal fungi induce differences in cellular responses and fungal activity in a mycorrhiza-defective mutant of tomato (rmc)

2009 ◽  
Vol 36 (1) ◽  
pp. 86 ◽  
Author(s):  
Maria Manjarrez ◽  
Meredith Wallwork ◽  
Sally E. Smith ◽  
F. Andrew Smith ◽  
Sandy Dickson
Keyword(s):  
Mycorrhizal Fungi ◽  
Laser Scanning ◽  
Plant Defence ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Cellular Responses ◽  
Wild Type ◽  
Nuclear Movement ◽  
Callose Deposition ◽  
Defence Responses

The reduced mycorrhizal colonisation (rmc) mutant of tomato forms different phenotypes with different arbuscular mycorrhizal (AM) fungi. Our aim was to characterise microscopically the cellular responses in plant and fungus in order to reveal how these varied when colonisation was blocked at different stages. Synchronised colonisation coupled with vital staining, autofluorescence and laser scanning confocal microscopy (LSCM) were used to determine how long the AM fungi stay alive during the interactions with rmc, whether nuclear repositioning occurred in the same way as in wild-type interactions and whether there was evidence for deployment of defence responses. The results showed that (1) all the AM fungi tested were attracted to roots of rmc, on which they developed active external mycelium and appressoria, the latter sometimes in higher numbers than on the wild type; (2) plant cellular responses, such as nuclear movement, occurred only when the AM fungus was able to penetrate the epidermal cells of rmc; and (3) plant defence responses such as autofluorescence were observed only transiently and callose deposition was not involved in blocking AM fungi in rmc. The results demonstrate that multi-step AM colonisation is not only an outcome of cellular processes influenced by both plant and fungus, but is also modified by the capacity of different AM fungi to respond to the plant phenotype induced by the rmc mutation.

Microbial elicitors of plant defence responses activate transcription of a retrotransposon

1994 ◽  
Vol 5 (4) ◽  
pp. 535-542 ◽  
Author(s):  
Sylvie Pouteau ◽  
Marie-Angele Grandbastien ◽  
Martine Boccara
Keyword(s):  
Plant Defence ◽  
Defence Responses ◽  
Plant Defence Responses

scholarly journals Integrating metabolomics and targeted gene expression to uncover potential biomarkers of fungal/oomycetes-associated disease susceptibility in grapevine

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Marisa Maia ◽  
António E. N. Ferreira ◽  
Rui Nascimento ◽  
Filipa Monteiro ◽  
Francisco Traquete ◽  
...  
Keyword(s):  
Gene Expression ◽  
Plant Defence ◽  
Breeding Programs ◽  
Analysis Group ◽  
Expression Of Genes ◽  
Leucoanthocyanidin Reductase ◽  
Defence Responses ◽  
Targeted Gene Expression ◽  
Plant Defence Responses ◽  
First Time

Abstract Vitis vinifera, one of the most cultivated fruit crops, is susceptible to several diseases particularly caused by fungus and oomycete pathogens. In contrast, other Vitis species (American, Asian) display different degrees of tolerance/resistance to these pathogens, being widely used in breeding programs to introgress resistance traits in elite V. vinifera cultivars. Secondary metabolites are important players in plant defence responses. Therefore, the characterization of the metabolic profiles associated with disease resistance and susceptibility traits in grapevine is a promising approach to identify trait-related biomarkers. In this work, the leaf metabolic composition of eleven Vitis genotypes was analysed using an untargeted metabolomics approach. A total of 190 putative metabolites were found to discriminate resistant/partial resistant from susceptible genotypes. The biological relevance of discriminative compounds was assessed by pathway analysis. Several compounds were selected as promising biomarkers and the expression of genes coding for enzymes associated with their metabolic pathways was analysed. Reference genes for these grapevine genotypes were established for normalisation of candidate gene expression. The leucoanthocyanidin reductase 2 gene (LAR2) presented a significant increase of expression in susceptible genotypes, in accordance with catechin accumulation in this analysis group. Up to our knowledge this is the first time that metabolic constitutive biomarkers are proposed, opening new insights into plant selection on breeding programs.

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