Induced resistance for plant defense

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 Defense

10.1002/9781118371848 ◽

2014 ◽

Keyword(s):

Plant Defense ◽

Induced Resistance

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Comparative Transcriptome Analysis of Genes Involved in Penicillium Chrysogenum Induced Resistance to Root-knot Nematode in Tomato

10.21203/rs.3.rs-117883/v1 ◽

2020 ◽

Author(s):

Mengyue Zhang ◽

Aatika Sikandar ◽

Xiaofeng Zhu ◽

Yuanyuan Wang ◽

Xiaoyu Liu ◽

...

Keyword(s):

Plant Defense ◽

Induced Resistance ◽

Penicillium Chrysogenum ◽

Molecular Mechanisms ◽

Management Approach ◽

Root Knot Nematode ◽

Tomato Root ◽

Basal Resistance ◽

Promising Alternative ◽

Wide Range

Abstract Background: Tomato root-knot nematode is a soil-borne disease caused by Meloidogyne incognita. Enhancement of natural plant-defense mechanisms to provide resistance against pathogens may be a promising alternative environmentally friendly nematode management approach. Recently, the biocontrol effect against different pathogens in the presence of Penicillium chrysogenum has been reported in a wide range of plants and pathogens. For understanding the molecular mechanisms of the resistance induced by P. chrysogenum Snef1216 to RKN, transcriptomes of inducer control ‘IRCK’ (induced by Snef1216 only) and pathogen + inducer ‘IRN’ were compared to those of control groups, namely negative control ‘CKCK’ (no inoculum), pathogen control ‘CKN’ (inoculum of RKN only).Results: Numerous high-quality reads were generated by Novogene, means of the RNA-seq method. After being aligned to the reference genome, four comparative transcriptomic profile maps between any pairwise comparisons were obtained to find significantly differentially expressed genes (DEGs) and three databases of induced resistance (IR)-related, nematode pathogenesis (NP)-related and basal resistance (BR)-related genes were gotten. By hierarchal clustering, the phylogenetic relationship between highly and fewer DGEs were obtained and classified the resistance and susceptible responses into two clusters after inoculation with RKN. Finally, the results were verified by RT-qPCR and analysis of important plant defense enzymes.Conclusions: Within an integrated and more sustainable management approach, the use of biocontrol organisms, like P. chrysogenum, seems to be a promising alternative.

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Induced Resistance by Ascorbate Oxidation Involves Potentiating of the Phenylpropanoid Pathway and Improved Rice Tolerance to Parasitic Nematodes

Frontiers in Plant Science ◽

10.3389/fpls.2021.713870 ◽

2021 ◽

Vol 12 ◽

Author(s):

Richard Raj Singh ◽

Jessil Ann Pajar ◽

Kris Audenaert ◽

Tina Kyndt

Keyword(s):

Plant Defense ◽

Induced Resistance ◽

Phenylpropanoid Pathway ◽

Nematode Infection ◽

Systemic Resistance ◽

Ascorbate Oxidase ◽

Parasitic Nematodes ◽

Reflection Index ◽

Pal Activity ◽

Activity Measurements

Anticipating an increased ecological awareness, scientists have been exploring new strategies to reduce the use of chemical pesticides to control pests and diseases. Triggering the intrinsic plant defense system is one of the promising strategies to reduce yield loss by pathogenic organisms, such as nematodes. Ascorbate oxidase (AO) enzyme plays an important role in plant defense by regulating the apoplastic ascorbate/dehydroascorbate (DHA) ratio via the ascorbate oxidation process. Ascorbate oxidation is known to induce systemic resistance in rice against parasitic root-knot nematodes (RKN). Here, we sought to evaluate if AO- or DHA-induced resistance (IR) against RKN M. graminicola involves activation of the phenylpropanoid pathway and whether this IR phenotype has potential effects on growth of rice seedlings under stressed and unstressed conditions. Our results show that AO/DHA-IR against these parasitic nematodes is dependent on activation of phenylalanine ammonia lyase (PAL). However, application of reduced ascorbic acid (AA) did not induce this response. Gene expression analysis via qRT-PCR showed that OsPAL2 and OsPAL4 are highly expressed in AO/DHA-sprayed nematode-infected roots and PAL-activity measurements confirmed that AO/DHA spraying triggers the plants for primed activation of this enzyme upon nematode infection. AO/DHA-IR is not effective in plants sprayed with a chemical PAL inhibitor confirming that AO/DHA-induced resistance is dependent on PAL activity. Improved plant growth and low nematode infection in AO/DHA-sprayed plants was found to be correlated with an increase in shoot chlorophyll fluorescence (Fv/Fm), chlorophyll index (ChlIdx), and modified anthocyanin reflection index which were proven to be good above-ground parameters for nematode infestation. A detailed growth analysis confirmed the improved growth of AO/DHA-treated plants under nematode-infected conditions. Taken together, our results indicate that ascorbate oxidation enhances the phenylpropanoid-based response to nematode infection and leads to a tolerance phenotype in treated rice plants.

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