Role of plant hormones in plant defence responses

2008 ◽  
Vol 69 (4) ◽  
pp. 473-488 ◽  
Author(s):  
Rajendra Bari ◽  
Jonathan D. G. Jones
1993 ◽  
Vol 342 (1301) ◽  
pp. 265-270 ◽  

Recent studies suggest that the production of enzymes capable of degrading the cell walls of invading phytopathogenic fungi may be an important component of the defence response of plants. In this chapter, we summarize recent progress on the isolation and characterization of chitinolytic enzymes from higher plants. Emphasis is placed on experiments designed to study the regulation of chitinase gene expression in response to ethylene treatment or pathogen ingress and on determining the role of this enzyme in plant defence. The production of transgenic plants with enhanced resistance to attack by the fungal pathogen Rhizodonia solani is discussed.


Author(s):  
Javad Najafi ◽  
Tore Brembu ◽  
Ane Kjersti Vie ◽  
Rannveig Viste ◽  
Per Winge ◽  
...  

Abstract Small post-translationally modified peptides are important signalling components of plant defence responses against phytopathogens, acting both as positive and negative modulators. PAMP-INDUCED SECRETED PEPTIDE (PIP) 1 and 2 has been shown to amplify plant immunity. Here we investigate the role of the related peptide PIP3 in the regulation of immune response in Arabidopsis. Treatment with synthetic PIP peptides led to similar transcriptome reprogramming, indicating an effect on innate immunity-related processes and phytohormones, including jasmonic acid (JA) biosynthesis and signalling. PIP3 overexpressing (OX) plants showed enhanced growth inhibition in response to flg22 exposure. In addition, flg22-induced production of reactive oxygen species and callose deposition were significantly reduced in PIP3-OX plants. Interestingly, PIP3-OX plants showed increased susceptibility both toward Botrytis cinerea and the biotrophic pathogen Pseudomonas syringae. Expression of both JA and salicylic acid biosynthesis and signalling genes was more induced during B. cinerea infection in PIP3-OX plants compared with wild-type plants. Promoter and ChIP-seq analyses indicated that the transcription factors WRKY18, WRKY33 and WRKY40 cooperatively act as repressors for PIP3. The results point to a fine-tuning role for PIP3 in modulation of immunity through the regulation of SA and JA biosynthesis and signalling pathways in Arabidopsis.


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

Author(s):  
Mara Quaglia ◽  
Marika Bocchini ◽  
Benedetta Orfei ◽  
Roberto D’Amato ◽  
Franco Famiani ◽  
...  

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.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Marisa Maia ◽  
António E. N. Ferreira ◽  
Rui Nascimento ◽  
Filipa Monteiro ◽  
Francisco Traquete ◽  
...  

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.


2016 ◽  
Vol 106 (3) ◽  
pp. 368-377 ◽  
Author(s):  
C. Sempruch ◽  
S. Goławska ◽  
P. Osiński ◽  
B. Leszczyński ◽  
P. Czerniewicz ◽  
...  

AbstractThe study aimed to quantify the influence of common plant polyamines and tyramine on probing behaviour in the bird cherry-oat aphid (Rhopalosiphum padi L.). Electrical penetration graphs (DC) were used to monitor the probing and feeding behaviour of R. padi exposed to the amines agmatine, cadaverine, putrescine, spermidine, spermine and tyramine. The study results showed that the analyzed amines tended to shorten the stylet activity of aphids in the gels (as indicated by the g-C pattern), prolong the duration of non-probing behaviour (g-np pattern) and decrease salivation into the gels (g-E1pattern) and ingestion from the gels (g-G pattern). The 10 mM concentration of the studied amines, especially cadaverine, reduced or completely inhibited aphid ingestion. The obtained results demonstrate that plant amines participate in plant defence responses to R. padi through disturbance of its probing behaviour and the intensity of such effects is concentration dependent.


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