Induced Resistance for Plant Defence

Summary The root-knot nematode, Meloidogyne incognita, is a destructive pathogen with a broad host range, causing serious damage to cucumber globally. Synthetic chemical nematicides are effective for controlling nematodes but they pose harmful effects on the environment and human beings. Thus, the development of natural plant defence mechanisms to contribute resistance to M. incognita is a potentially eco-friendly alternative. In recent decades, the biocontrol activity of P. chrysogenum against various pests and pathogens has been investigated in a variety of plants. The present study aimed to understand the molecular mechanisms of induced resistance by P. chrysogenum strain Snef1216 against M. incognita through its use as seed coating. The expression of 80 genes in roots of cucumber, Cucumis sativus, at four different infection time intervals was examined. Genes belonging to defence, signal transduction, growth, binding and transportation, secondary metabolism, transcription factor, cell death, oxidoreductases and cell wall modification categories were selected and examined with specific primers via RT-qPCR. The greater expression of defence-related or other vital genes demonstrated that P. chrysogenum strain Snef1216 induced priming of defence and plant growth-promoting responses. These data could contribute to breeding new nematode-resistant and biomass-enhancing cultivars of cucumber. Overall, application of P. chrysogenum strain Snef1216 may be a potential alternative to chemical nematicides as part of a future more effective management strategy.

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Priming Effect of Thiamine on the Enhancement of Induced Resistance to the Plant Disease Phytophthora Nicotianae in Tobacco

10.21203/rs.3.rs-279029/v1 ◽

2021 ◽

Author(s):

Liu Tao ◽

Tian Suohui ◽

Chen Yanping ◽

Zi Shuhui ◽

Mei Jian ◽

...

Keyword(s):

Plant Defense ◽

Induced Resistance ◽

Priming Effect ◽

Plant Disease ◽

Plant Defence ◽

Vitamin B1 ◽

Phytophthora Nicotianae ◽

Callose Deposition ◽

Pronounced Increase ◽

Defense Reactions

Abstract Induced resistance by elicitors is considered to be an eco-friendly strategy to stimulate plant defense against pathogen attack. Thiamine (vitamin B1,VB1) can act as a plant defence trigger, or priming agent, leading to a rapid counterattack on pathogen invasion.To date, the mechanisms by which VB1 provides protection against plant disease have yet to be fully elucidated, expecially no reports about VB1 treatment influenced the development of Phytophthora nicotianae in plant. Tobacco black shank (TBS) caused by P. nicotianae is destructive to almost all tobacco cultivars and is widespread in many tobacco-growing countries. In the present study, the priming effect of VB1 on tobacco against the disease P. nicotianae and its biochemical and molecular impact on plant defense mechanisms were evaluated. Base on the effect of VB1 on mycelial growth and zoospore formation, the appropriate VB1 treatment was used in protecting tobacco against P. nicotianae. For VB1 pretreatment, tobacco exhibited a significant reduction in disease severity. Consistent with the occurrence of induced resistance, the pronounced increase in H2O2 level, phenylalanine ammonia lyase (PAL) and peroxidase (POD) activities were observed. For defense reactions, VB1 promoted the increases of H2O2, SA and lignin contents. Moreover, the expressions of PR1, PR5, NPR1, PAL, CM1, H1N1 and EFE26 were induced by VB1, which also involved in defense reactions. Our findings indicate that the priming effect of VB1 may partially depend on the production of the callose deposition, H2O2 accumulation, and hormone SA production.

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Induced Resistance for Plant Defence

10.3389/978-2-88919-925-9 ◽

2016 ◽

Keyword(s):

Induced Resistance ◽

Plant Defence

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Mycorrhiza induced resistance (MIR): a defence developed through synergistic engagement of phytohormones, metabolites and rhizosphere

Functional Plant Biology ◽

10.1071/fp20035 ◽

2020 ◽

Vol 47 (10) ◽

pp. 880

Author(s):

Swapnil B. Kadam ◽

Anupama A. Pable ◽

Vitthal T. Barvkar

Keyword(s):

Secondary Metabolites ◽

Induced Resistance ◽

Molecular Mechanisms ◽

Plant Defence ◽

Plant Secondary Metabolites ◽

Symbiotic Association ◽

Mycorrhizal Network ◽

Pest Insects ◽

Nutritional Benefits ◽

The Cost

Plants get phosphorus, water and other soil nutrients at the cost of sugar through mycorrhizal symbiotic association. A common mycorrhizal network (CMN) – a dense network of mycorrhizal hyphae – provides a passage for exchange of chemicals and signals between the plants sharing CMN. Mycorrhisation impact plants at hormonal, physiological and metabolic level and successful symbiosis also regulates ecology of the plant rhizosphere. Apart from nutritional benefits, mycorrhisation provides an induced resistance to the plants known as mycorrhiza induced resistance (MIR). MIR is effective against soil as well as foliar pathogens and pest insects. In this review, molecular mechanisms underlying MIR such as role of phytohormones, their cross talk and priming effect are discussed. Evidence of MIR against economically important pathogens and pest insects in different plants is summarised. Mycorrhiza induces many plant secondary metabolites, many of which have a role in plant defence. Involvement of these secondary metabolites in mycorrhisation and their putative role in MIR are further reviewed. Controversies about MIR are also briefly discussed in order to provide insights on the scope for research about MIR. We have further extended our review with an open ended discussion about the possibilities for transgenerational MIR.

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Phosphatidic acid synthesis, octadecanoic pathway and fatty acids content as lipid markers of exogeneous salicylic acid-induced elicitation in wheat

Functional Plant Biology ◽

10.1071/fp15347 ◽

2016 ◽

Vol 43 (6) ◽

pp. 512

Author(s):

Christine Tayeh ◽

Béatrice Randoux ◽

Frédéric Laruelle ◽

Natacha Bourdon ◽

Philippe Reignault

Keyword(s):

Gene Expression ◽

Salicylic Acid ◽

Lipid Metabolism ◽

Phosphatidic Acid ◽

Induced Resistance ◽

Lipid Transfer Protein ◽

Plant Defence ◽

Acid Synthesis ◽

Lipid Transfer ◽

Octadecanoid Pathway

Activators of plant defence responses against pathogens are a potential alternative to fungicides, and the well-known resistance inducer salicylic acid (SA) protects wheat (Triticum aestivum L.) against powdery mildew. The aim of our work was to investigate through biochemical and molecular approaches whether lipid metabolism alteration could be considered as a characteristic feature of induced resistance in wheat upon SA infiltration. Expression levels of lox, PI-PLC2 and ltp genes encoding for a lipoxygenase (LOX), a phospholipase C2 and a lipid-transfer protein, respectively, were investigated. Increase of phosphatidic acid (PA) content 48 h after SA infiltration in wheat leaves, upregulation of PI-PLC2 gene expression and increased diacylglycerol content were recorded, indicating the involvement of the PLC pathway in the PA synthesis. The wheat octadecanoid pathway was shown to be highly responsive to SA infiltration through simultaneous increases in lox gene expression and LOX activity, as well as a reduction in the content of linolenic acid. Changes in several FA contents and increases of the ltp gene expression were also recorded during the latest hours after SA infiltration. The status of lipid metabolism, as well as the connections between its components as markers of SA-induced resistance in wheat, are discussed.

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