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

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.

scholarly journals Knock-Down of Gossypol-Inducing Cytochrome P450 Genes Reduced Deltamethrin Sensitivity in Spodoptera exigua (Hübner)

2019 ◽  
Vol 20 (9) ◽  
pp. 2248 ◽  
Author(s):  
Muhammad Hafeez ◽  
Sisi Liu ◽  
Saad Jan ◽  
Le Shi ◽  
G. Mandela Fernández-Grandon ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Secondary Metabolites ◽  
Molecular Mechanisms ◽  
Spodoptera Exigua ◽  
Plant Secondary Metabolites ◽  
Detoxification Enzymes ◽  
Beet Armyworm ◽  
Cytochrome P450 Monooxygenases ◽  
Control Group ◽  
P450 Monooxygenases

Plants employ an intricate and dynamic defense system that includes physiological, biochemical, and molecular mechanisms to counteract the effects of herbivorous attacks. In addition to their tolerance to phytotoxins, beet armyworm has quickly developed resistance to deltamethrin; a widely used pyrethroid insecticide in cotton fields. The lethal concentration (LC50) required to kill 50% of the population of deltamethrin to gossypol-fed Spodoptera exigua larvae was 2.34-fold higher than the control group, suggesting a reduced sensitivity as a consequence of the gossypol diet. Piperonyl butoxide (PBO) treatment was found to synergize with deltamethrin in gossypol-fed S. exigua larvae. To counteract these defensive plant secondary metabolites, beet armyworm elevates their production of detoxification enzymes, including cytochrome P450 monooxygenases (P450s). Gossypol-fed beet armyworm larvae showed higher 7-ethoxycoumarin-O-deethylase (ECOD) activities and exhibited enhanced tolerance to deltamethrin after 48 and 72 h when compared to the control. Moreover, gossypol pretreated S. exigua larvae showed faster weight gain than the control group after transferring to a deltamethrin-supplemented diet. Meanwhile, gossypol-induced P450s exhibited high divergence in the expression level of two P450 genes: CYP6AB14 and CYP9A98 in the midgut and fat bodies contributed to beet armyworm tolerance to deltamethrin. Knocking down of CYP6AB14 and CYP9A98, via double-stranded RNAs (dsRNA) in a controlled diet, rendered the larvae more sensitive to the insecticide. These data demonstrate that generalist insects can exploit secondary metabolites from host plants to enhance their defense systems against other toxic chemicals. Impairing this defense pathway by RNA interference (RNAi) holds a potential to eliminate the pest’s tolerance to insecticides and, therefore, reduce the required dosages of agrochemicals in pest control.

Benzoxazinoids selectively affect maize root-associated nematode taxa

2021 ◽  
Author(s):  
Md Maniruzzaman Sikder ◽  
Mette Vestergård ◽  
Tina Kyndt ◽  
Inge S Fomsgaard ◽  
Enoch Narh Kudjordjie ◽  
...  
Keyword(s):  
Secondary Metabolites ◽  
Plant Defence ◽  
Plant Secondary Metabolites ◽  
Nematode Species ◽  
Nematode Community ◽  
Maize Root ◽  
Parasitic Nematodes ◽  
Root Lesion Nematode ◽  
Nematode Communities ◽  
Lesion Nematode

Abstract Although the effects of plant secondary metabolites on plant defence have been studied for decades, the exact roles of secondary metabolites in shaping plant-associated microbial and nematode communities remain elusive. We evaluated the effects of benzoxazinoids, a group of secondary metabolites present in several cereals, on root-associated nematodes. We employed 18S rRNA metabarcoding to compare maize root-associated nematode communities in a bx1 knockout maize line impaired in benzoxazinoid synthesis and in its parental wild type. Both genotype and plant age affected the composition of the nematode community in the roots, and the effects of benzoxazinoids on nematode communities were stronger in the roots than in the rhizosphere. Differential abundance analysis and quantitative PCR showed that the root lesion nematode Pratylenchus neglectus was enriched in the bx1 mutant line, while another root lesion nematode, Pratylenchus crenatus, was reduced. Correlation analysis showed that benzoxazinoid concentrations in maize roots mostly correlated negatively with the relative abundance of nematode sequence reads. However, positive correlations between benzoxazinoids and nematode taxa, including several plant-parasitic nematodes, were also identified. Our detailed nematode community analysis suggests differential and selective effects of benzoxazinoids on soil nematodes depending on both the nematode species and the benzoxazinoid compound.

Analysis of gene expression in cucumber roots interacting with Penicillium chrysogenum strain Snef1216 through seed coating, which induced resistance to Meloidogyne incognita

Nematology ◽  
2021 ◽  
pp. 1-15
Author(s):  
Aatika Sikandar ◽  
Mengyue Zhang ◽  
Ruowei Yang ◽  
Dan Liu ◽  
Xiaofeng Zhu ◽  
...  
Keyword(s):  
Induced Resistance ◽  
Meloidogyne Incognita ◽  
Molecular Mechanisms ◽  
Plant Defence ◽  
Broad Host Range ◽  
Seed Coating ◽  
Human Beings ◽  
Root Knot Nematode ◽  
Cell Wall Modification ◽  
Plant Growth Promoting

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.

scholarly journals Exploring structurally diverse plant secondary metabolites as a potential source of drug targeting different molecular mechanisms of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) pathogenesis: An in silico approach

2020 ◽  
Author(s):  
Hariprasad. P. ◽  
H. G. Gowtham ◽  
D. O. Monu ◽  
Y. Ajay ◽  
C. Gourav ◽  
...  
Keyword(s):  
Secondary Metabolites ◽  
Host Cell ◽  
Molecular Mechanisms ◽  
Plant Secondary Metabolites ◽  
Natural Occurrence ◽  
Primary Concern ◽  
Lipinski’S Rule ◽  
Transmembrane Serine Protease

Abstract Plants are endowed with a large pool of structurally diverse small molecules known as secondary metabolites. Present study aims to virtually screen these plant secondary metabolites (PMS) for their possible anti-SARS-CoV-2 properties targeting four protein/enzymes which determines viral pathogenesis. Results of molecular docking and data analysis revealed a unique pattern of structurally similar PSM interacting with the target protein. Among the top-ranked PSM with lower binding energy, >50% were triterpenoids against viral spike protein, >32% were flavonoids and their glycoside against Human transmembrane serine protease, >16% were flavonol glycosides and >16% were Anthocyanidine against viral main protease and >13% were flavonol glycoside against viral RNA dependet RNA polymerase. The primary concern about these PSM is their bioavailability. However, several PSM recorded higher bioavailability score and found fulfilling drug-likeness characters as per Lipinski's rule. Natural occurrence, biotransformation, bioavailability of selected PSM and their interaction with the target site of selected proteins were discussed in detail. Further, we hypothesized the use of selected PSM to cure the COVID-19 by inhibiting the process of viral host cell recognition and replication in host cell. However, these PSM needs thorough in vitro and in vivo evaluation before taking them to clinical trials.

scholarly journals Multiple Molecular Mechanisms to Overcome Multidrug Resistance in Cancer by Natural Secondary Metabolites

2021 ◽  
Vol 12 ◽  
Author(s):  
Mahmoud Zaki El-Readi ◽  
Ahmed M. Al-Abd ◽  
Mohammad A. Althubiti ◽  
Riyad A. Almaimani ◽  
Hiba Saeed Al-Amoodi ◽  
...  
Keyword(s):  
Multidrug Resistance ◽  
Secondary Metabolites ◽  
Cancer Cells ◽  
Molecular Mechanisms ◽  
Plant Secondary Metabolites ◽  
Cell Growth Inhibition ◽  
Glycoprotein P ◽  
P Glycoprotein ◽  
Drug Concentrations ◽  
Pharmaceutical Agents

Plant secondary metabolites (SMs) common natural occurrences and the significantly lower toxicities of many SM have led to the approaching development and use of these compounds as effective pharmaceutical agents; especially in cancer therapy. A combination of two or three of plant secondary metabolites together or of one SM with specific anticancer drugs, may synergistically decrease the doses needed, widen the chemotherapeutic window, mediate more effective cell growth inhibition, and avoid the side effects of high drug concentrations. In mixtures they can exert additive or even synergistic activities. Many SM can effectively increase the sensitivity of cancer cells to chemotherapy. In phytotherapy, secondary metabolites (SM) of medicinal plants can interact with single or multiple targets. The multi-molecular mechanisms of plant secondary metabolites to overcome multidrug resistance (MDR) are highlighted in this review. These mechanisms include interaction with membrane proteins such as P-glycoprotein (P-gp/MDR1); an ATP-binding cassette (ABC) transporter, nucleic acids (DNA, RNA), and induction of apoptosis. P-gp plays an important role in the development of MDR in cancer cells and is involved in potential chemotherapy failure. Therefore, the ingestion of dietary supplements, food or beverages containing secondary metabolites e.g., polyphenols or terpenoids may alter the bioavailability, therapeutic efficacy and safety of the drugs that are P-gp substrates.

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