RNAi-induced silencing of an effector confers transcriptional oscillation in another group of effectors in the root-knot nematode, Meloidogyne incognita

Nematology ◽  
2016 ◽  
Vol 18 (7) ◽  
pp. 857-870 ◽  
Author(s):  
Tagginahalli N. Shivakumara ◽  
Pradeep K. Papolu ◽  
Tushar K. Dutta ◽  
Divya Kamaraju ◽  
Sonam Chaudhary ◽  
...  
Keyword(s):  
Cell Wall ◽  
Meloidogyne Incognita ◽  
Future Research ◽  
Developmental Pathway ◽  
Root Knot Nematode ◽  
Cell Wall Degrading Enzymes ◽  
Phenotypic Data ◽  
Effector Genes ◽  
Successful Infection

The sophisticated parasitic tactic of sedentary endoparasitic nematodes seems to involve the simultaneous alteration of the expression of multitude of its effector genes in order to hijack the plant metabolic and developmental pathway. In concordance with this hypothesis, we have targeted some candidate effector genes of Meloidogyne incognita to understand the possible interaction among those effectors for successful infection of the host plant. In vitro RNAi strategy was used to knock down M. incognita-specific pioneer effector genes, such as msp-18, msp-20, msp-24, msp-33 and msp-16 (known to interact with plant transcription factor), to investigate their possible effect on the expression of key cell wall-degrading enzymes (CWDE) and vice versa. Supported by the phenotypic data, intriguingly our study revealed that induced suppression of these pioneer genes cause transcriptional alteration of CWDE genes in M. incognita. This remarkable finding may provide some useful links for future research on nematode effector interaction.

scholarly journals Genome expression dynamics reveals parasitism regulatory landscape of the root-knot nematode Meloidogyne incognita and a promoter motif associated with effector genes

2021 ◽  
Author(s):  
Martine Da Rocha ◽  
Caroline Bournaud ◽  
Julie Dazeniere ◽  
Peter Thorpe ◽  
Clement Pellegrin ◽  
...  
Keyword(s):  
Gene Expression ◽  
Meloidogyne Incognita ◽  
Life Stage ◽  
Regulation Of Gene Expression ◽  
Root Knot Nematode ◽  
Root Knot Nematodes ◽  
Control Of Gene Expression ◽  
Precise Control ◽  
Effector Genes ◽  
Spatio Temporal

Root-knot nematodes are the major contributor to the crop losses caused by nematodes. Root-knot nematodes secrete effectors into the plant, derived from two sets of pharyngeal gland cells, to manipulate host physiology and immunity. Successful completion of the life cycle, involving successive molts from egg to adult, covers morphologically and functionally distinct stages and will require precise control of gene expression, including effectors. The details of how root-knot nematodes regulate transcription remain sparse. Here, we report a life stage-specific transcriptome of Meloidogyne incognita. Combined with an available annotated genome, we explore the spatio-temporal regulation of gene expression. We reveal gene expression clusters and predicted functions that accompany the major developmental transitions. Focusing on effectors, we identify a putative cis-regulatory motif associated with expression in the dorsal glands: providing an insight into effector regulation. We combine the presence of this motif with several other criteria to predict a novel set of putative dorsal gland effectors. Finally, we show this motif, and thereby its utility, is broadly conserved across the Meloidogyne genus and termed it Mel-DOG. Taken together, we provide the first genome-wide analysis of spatio-temporal gene expression in a root-knot nematode, and identify a new set of candidate effector genes that will guide future functional analyses.

Evaluation of Botanicals Toxicants against Root-knot Nematode, Meloidogyne incognita in vitro

2017 ◽  
Vol 4 (3) ◽  
pp. 1-7 ◽  
Author(s):  
Amir Khan ◽  
Moh Tariq ◽  
Mohd Asif ◽  
Mansoor Siddiqui
Keyword(s):  
Meloidogyne Incognita ◽  
Root Knot Nematode

Differentiation and cell wall degrading enzymes in the obligately biotrophic rust fungus Uromyces viciae-fabae

1995 ◽  
Vol 73 (S1) ◽  
pp. 624-631 ◽  
Author(s):  
Holger Deising ◽  
Martina Rauscher ◽  
Marc Haug ◽  
Stefan Heiler
Keyword(s):  
Cell Wall ◽  
Rust Fungus ◽  
Cell Wall Degrading Enzymes ◽  
Chitin Deacetylase ◽  
Infection Structure ◽  
Degrading Enzymes ◽  
Successful Infection ◽  
Serine Esterases ◽  
Polygalacturonate Lyase ◽  
Mother Cells

Rust fungi differentiate a series of complex infection structures to infect their host plants. Artificial membranes providing a signal for the induction of infection structure differentiation have been used to study events taking place during early stages of host–pathogen interaction. During the prepenetration phase, serine esterases, one of which shows cutinase activity, appear to be important for adhesion of uredospores of Uromyces viciae-fabae to the plant cuticle. When the fungus grows through the stomatal opening, chitin deacetylase activity increases drastically. The role of this enzyme in masking and preventing degradation of fungal structures by plant chitinases is discussed. Different isoforms of protease, cellulase, and pectin methylesterases (PME) are formed when the fungus enters the intercellular space, and synthesis of polygalacturonate lyase (PL) coincides with formation of haustorial mother cells. Based on the physicochemical and catalytic properties of these cell wall degrading enzymes a model is presented that explains highly localized breaching of plant cell walls by obligate biotrophs. cDNAs corresponding to genes activated during late stages of infection structure differentiation of Uromyces viciae-fabae have been isolated by differential hybridization. The transcripts of the genes designated rif16 and rif21 occur when haustorial mother cells are formed, and the corresponding gene products may thus be important for successful infection. Key words: adhesion, cell wall degrading enzymes, chitin deacetylase, infection structure differentiation, penetration process, rif genes.

Pyrrolizidine alkaloids of Chromolaena odorata act as nematicidal agents and reduce infection of lettuce roots by Meloidogyne incognita

Nematology ◽  
2007 ◽  
Vol 9 (3) ◽  
pp. 343-349 ◽  
Author(s):  
Michael Boppré ◽  
Tim Thoden ◽  
Johannes Hallmann
Keyword(s):  
Meloidogyne Incognita ◽  
Pyrrolizidine Alkaloids ◽  
Invasive Weeds ◽  
Chromolaena Odorata ◽  
Root Knot Nematode ◽  
In Vivo Experiments ◽  
Valuable Element ◽  
Plant Compounds

Abstract1,2-dehydropyrrolizidine alkaloids (PAs) represent a class of secondary plant compounds that are active in defence against herbivory. They are present in Chromolaena odorata, one of the most invasive weeds of Asia and Africa. In vitro studies demonstrate that pure PAs from C. odorata roots have nematicidal effects on the root-knot nematode Meloidogyne incognita, even at concentrations of 70-350 ppm. In vivo experiments show that mulch or aqueous crude extracts from C. odorata roots reduce the infection of lettuce by M. incognita. Thus, the use of PA-containing plants appears to be a valuable element for integrated nematode management.

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