Engineering broad root-knot resistance in transgenic plants by RNAi silencing of a conserved and essential root-knot nematode parasitism gene

The root-knot nematode, Meloidogyne incognita, is an obligate parasite which depends entirely on the host plant for its nutrition. Root-knot nematodes induce the formation of a highly specialized feeding site consisting of several giant cells surrounded by a network of vascular tissues. Nutrients, including amino acids and sugars, are transferred apoplastically from the vascular tissues to the feeding site. Using Arabidopsis thaliana lacking the vascular-expressed amino acid permeases (AAP) AAP3 or AAP6, we demonstrate that disruption of amino acid transport can affect nematode parasitism. Nematode infestation levels are significantly reduced on the aap3 and aap6 mutants. AAP3 and AAP6 act distinctly in the transport of amino acids to the feeding site, as demonstrated by differences in their carrying capacity profiles. Furthermore, analyses of promoter: β-glucuronidase lines show different expression patterns for AAP3 and AAP6 in infected roots. In the aap3-3 mutant, part of the decrease in infestation is connected to a defect in early infection, where juveniles enter but then leave the root. Both aap3-3 and aap6-1 produce fewer females and produce more adult male nematodes. Additionally, detrimental effects are observed in the nematodes harvested from aap3-3 and aap6-1 mutants, including decreased egg hatching and infectivity and lower levels of lipid reserves. The transport of amino acids by AAP3 and AAP6 is important for nematode infection and success of the progeny.

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Root-Knot Nematode Parasitism Suppresses Host RNA Silencing

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-08-16-0160-r ◽

2017 ◽

Vol 30 (4) ◽

pp. 295-300 ◽

Cited By ~ 4

Author(s):

E. Walsh ◽

J. M. Elmore ◽

C. G. Taylor

Keyword(s):

Rna Silencing ◽

Plant Pathogens ◽

Giant Cells ◽

Root Knot Nematode ◽

Root Cells ◽

Feeding Site ◽

Nematode Parasitism ◽

Silencing Pathways ◽

Plant Pathosystems ◽

Viral Suppressors

Root-knot nematodes damage crops around the world by developing complex feeding sites from normal root cells of their hosts. The ability to initiate and maintain this feeding site (composed of individual “giant cells”) is essential to their parasitism process. RNA silencing pathways in plants serve a diverse set of functions, from directing growth and development to defending against invading pathogens. Influencing a host’s RNA silencing pathways as a pathogenicity strategy has been well-documented for viral plant pathogens, but recently, it has become clear that silencing pathways also play an important role in other plant pathosystems. To determine if RNA silencing pathways play a role in nematode parasitism, we tested the susceptibility of plants that express a viral suppressor of RNA silencing. We observed an increase in susceptibility to nematode parasitism in plants expressing viral suppressors of RNA silencing. Results from studies utilizing a silenced reporter gene suggest that active suppression of RNA silencing pathways may be occurring during nematode parasitism. With these studies, we provide further evidence to the growing body of plant-biotic interaction research that suppression of RNA silencing is important in the successful interaction between a plant-parasitic animal and its host.

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A Profile of Putative Parasitism Genes Expressed in the Esophageal Gland Cells of the Root-knot Nematode Meloidogyne incognita

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi.2003.16.5.376 ◽

2003 ◽

Vol 16 (5) ◽

pp. 376-381 ◽

Cited By ~ 150

Author(s):

Guozhong Huang ◽

Bingli Gao ◽

Tom Maier ◽

R. Allen ◽

Eric L. Davis ◽

...

Keyword(s):

Meloidogyne Incognita ◽

Secretory Proteins ◽

Cdna Clones ◽

Root Knot Nematode ◽

Long Distance ◽

Gland Cells ◽

Esophageal Gland ◽

Genes Encoding ◽

Nematode Parasitism ◽

Parasitism Genes

Identifying parasitism genes encoding proteins secreted from a nematode's esophageal gland cells and injected through its stylet into plant tissue is the key to understanding the molecular basis of nematode parasitism of plants. Meloidogyne incognita parasitism genes were cloned by microaspirating the cytoplasm from the esophageal gland cells of different parasitic stages to provide mRNA to create a gland cell-specific cDNA library by long-distance reverse-transcriptase polymerase chain reaction. Of 2,452 cDNA clones sequenced, deduced protein sequences of 185 cDNAs had a signal peptide for secretion and, thus, could have a role in root-knot nematode parasitism of plants. High-throughput in situ hybridization with cDNA clones encoding signal peptides resulted in probes of 37 unique clones specifically hybridizing to transcripts accumulating within the subventral (13 clones) or dorsal (24 clones) esophageal gland cells of M. incognita. In BLASTP analyses, 73% of the predicted proteins were novel proteins. Those with similarities to known proteins included a pectate lyase, acid phosphatase, and hypothetical proteins from other organisms. Our cell-specific analysis of genes encoding secretory proteins provided, for the first time, a profile of putative parasitism genes expressed in the M. incognita esophageal gland cells throughout the parasitic cycle.

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Identification and Characterization of a Novel Protein Disulfide Isomerase Gene (MgPDI2) from Meloidogyne graminicola

International Journal of Molecular Sciences ◽

10.3390/ijms21249586 ◽

2020 ◽

Vol 21 (24) ◽

pp. 9586

Author(s):

Zhongling Tian ◽

Zehua Wang ◽

Maria Munawar ◽

Jingwu Zheng

Keyword(s):

Cell Death ◽

Protein Disulfide Isomerase ◽

Catalytic Domain ◽

Root Knot Nematode ◽

Transient Expression Assay ◽

Disulfide Isomerase ◽

Meloidogyne Graminicola ◽

Promising Target ◽

Nematode Parasitism ◽

Protein Disulfide

Protein disulfide isomerase (PDI) is a multifunctional enzyme that catalyzes rate-limiting reactions such as disulfide bond formation, isomerization, and reduction. There is some evidence that indicates that PDI is also involved in host-pathogen interactions in plants. In this study, we show that the rice root-knot nematode, Meloidogyne graminicola, has evolved a secreted effector, MgPDI2, which is expressed in the subventral esophageal glands and up-regulated during the early parasitic stage of M. graminicola. Purified recombinant MgPDI2 functions as an insulin disulfide reductase and protects plasmid DNA from nicking. As an effector, MgPDI2 contributes to nematode parasitism. Silencing of MgPDI2 by RNA interference in the pre-parasitic second-stage juveniles (J2s) reduced M. graminicola multiplication and also increased M. graminicola mortality under H2O2 stress. In addition, an Agrobacterium-mediated transient expression assay found that MgPDI2 caused noticeable cell death in Nicotiana benthamiana. An intact C-terminal region containing the first catalytic domain (a) with an active motif (Cys-Gly-His-Cys, CGHC) and the two non-active domains (b and b′) is required for cell death induction in N. benthamiana. This research may provide a promising target for the development of new strategies to combat M. graminicola infections.

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The root-knot nematode: importance and impact on coffee in Brazil.

10.1079/9781789247541.0033 ◽

2021 ◽

pp. 238-244

Author(s):

Sonia M. L. Salgado ◽

Willian C. Terra

Keyword(s):

Life Cycle ◽

Integrated Management ◽

Economic Importance ◽

Economic Life ◽

Seedling Stage ◽

Root Knot Nematode ◽

Perennial Crop ◽

Nematode Parasitism ◽

Management Optimization ◽

Damage Symptoms

Abstract Coffee (Coffea spp.) is a crop of significant importance for Brazilian agribusiness, which in 2019 generated a gross revenue of US$3.73 billion. As a perennial crop, coffee stays in the field for many years, subjected to nematode parasitism from the seedling stage throughout the economic life of the plantation. In Brazil, it is a challenge for growers to produce coffee in the presence of the root-knot nematodes (RKN). Meloidogyne paranaensis and M. incognita are the most destructive species and their spread has expanded in recent years. This chapter discusses the economic importance, geographical distribution, host range, damage symptoms, biology and life cycle, interactions with other nematodes and pathogens, recommended integrated management, and management optimization of Meloidogyne paranaensis and M. incognita infesting coffee in Brazil.

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The 8D05 Parasitism Gene of Meloidogyne incognita Is Required for Successful Infection of Host Roots

Phytopathology ◽

10.1094/phyto-07-12-0173-r ◽

2013 ◽

Vol 103 (2) ◽

pp. 175-181 ◽

Cited By ~ 52

Author(s):

Bingye Xue ◽

Noureddine Hamamouch ◽

Chunying Li ◽

Guozhong Huang ◽

Richard S. Hussey ◽

...

Keyword(s):

Critical Role ◽

Specific Interaction ◽

Constitutive Expression ◽

Giant Cells ◽

Effector Proteins ◽

Meloidogyne Hapla ◽

Root Knot Nematode ◽

Successful Infection ◽

Parasitism Genes ◽

Parasitism Gene

Parasitism genes encode effector proteins that are secreted through the stylet of root-knot nematodes to dramatically modify selected plant cells into giant-cells for feeding. The Mi8D05 parasitism gene previously identified was confirmed to encode a novel protein of 382 amino acids that had only one database homolog identified on contig 2374 within the Meloidogyne hapla genome. Mi8D05 expression peaked in M. incognita parasitic second-stage juveniles within host roots and its encoded protein was limited to the subventral esophageal gland cells that produce proteins secreted from the stylet. Constitutive expression of Mi8D05 in transformed Arabidopsis thaliana plants induced accelerated shoot growth and early flowering but had no visible effects on root growth. Independent lines of transgenic Arabidopsis that expressed a double-stranded RNA complementary to Mi8D05 in host-derived RNA interference (RNAi) tests had up to 90% reduction in infection by M. incognita compared with wild-type control plants, suggesting that Mi8D05 plays a critical role in parasitism by the root-knot nematode. Yeast two-hybrid experiments confirmed the specific interaction of the Mi8D05 protein with plant aquaporin tonoplast intrinsic protein 2 (TIP2) and provided evidence that the Mi8D05 effector may help regulate solute and water transport within giant-cells to promote the parasitic interaction.

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Root-knot nematode parasitism and host response: molecular basis of a sophisticated interaction

Molecular Plant Pathology ◽

10.1046/j.1364-3703.2003.00170.x ◽

2003 ◽

Vol 4 (4) ◽

pp. 217-224 ◽

Cited By ~ 121

Author(s):

Pierre Abad ◽

Bruno Favery ◽

Marie-Noëlle Rosso ◽

Philippe Castagnone-Sereno

Keyword(s):

Molecular Basis ◽

Host Response ◽

Root Knot Nematode ◽

Nematode Parasitism

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Significant effects of RNAi silencing of the venom allergen-like protein (Mhi-vap-1 ) of the root-knot nematode Meloidogyne hispanica in the early events of infection

Plant Pathology ◽

10.1111/ppa.12673 ◽

2017 ◽

Vol 66 (8) ◽

pp. 1329-1337 ◽

Cited By ~ 4

Author(s):

A. Duarte ◽

C. Maleita ◽

C. Egas ◽

I. Abrantes ◽

R. Curtis

Keyword(s):

Root Knot Nematode ◽

Rnai Silencing ◽

Venom Allergen

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Kök-Ur Nematodları (Meloidogyne spp.)’nda Parazitizm

Turkish Journal of Agriculture - Food Science and Technology ◽

10.24925/turjaf.v2i4.160-170.83 ◽

2014 ◽

Vol 2 (4) ◽

pp. 160

Author(s):

Gökhan Aydınlı ◽

Sevilhan Mennan

Keyword(s):

Molecular Basis ◽

Host Response ◽

Host Plants ◽

Point Of View ◽

Root Knot Nematode ◽

Root Knot Nematodes ◽

Nematode Management ◽

Meloidogyne Spp ◽

Nematode Parasitism ◽

Complex Relationships

Root-knot nematodes (Meloidogyne spp.) have specialized and complex relationships with their host plants. A better understanding of interaction between nematode and their host will help to provide new point of view for root-knot nematode management. For this purpose, recently investigations on cellular and molecular basis of root-knot nematode parasitism and host response were reviewed.

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