scholarly journals Phytol, a constituent of chlorophyll, induces root-knot nematode resistance in Arabidopsis via the ethylene signaling pathway

2020 ◽  
Author(s):  
Taketo Fujimoto ◽  
Hiroshi Abe ◽  
Takayuki Mizukubo ◽  
Shigemi Seo
Keyword(s):  
Nematode Resistance ◽  
Ethylene Signaling ◽  
Severe Damage ◽  
Root Knot Nematode ◽  
Chlorophyll Contents ◽  
Aerial Parts ◽  
Wide Range ◽  
Ethylene Signaling Pathway ◽  
Meloidogyne Spp ◽  
Arabidopsis Mutant

Root-knot nematodes (RKNs; Meloidogyne spp.) parasitize the roots and/or stems of a wide range of plant species, resulting in severe damage to the parasitized plant. The phytohormone ethylene (ET) plays an important role in signal transduction pathways leading to resistance against RKNs. However, little is currently known about the induction mechanisms of ET-dependent RKN resistance. Inoculation of Arabidopsis (Arabidopsis thaliana) roots with RKNs decreased chlorophyll contents in aerial parts of the plant. We observed accumulation of phytol, a constituent of chlorophyll and a precursor of tocopherols, in RKN-parasitized roots. Application of sclareol, a diterpene that has been shown to induce ET-dependent RKN resistance, to the roots of Arabidopsis plants increased phytol contents in roots accompanied by a decrease in chlorophyll in aerial parts. Exogenously applied phytol inhibited RKN penetration of roots without exhibiting nematicidal activity. This phytol-induced inhibition of RKN penetration was attenuated in the ET-insensitive Arabidopsis mutant ein2-1. Exogenously applied phytol enhanced the production of α-tocopherol and expression of VTE5, a gene involved in tocopherol production, in Arabidopsis roots. α-Tocopherol exerted similar induction of RKN resistance as phytol and showed increased accumulation in roots inoculated with RKNs. Furthermore, the Arabidopsis vte5 mutant displayed no inhibition of RKN penetration in response to phytol. These results suggest that exogenously applied phytol induces EIN2-dependent RKN resistance, possibly via tocopherol production.

scholarly journals Heterologous Expression of the Mi-1.2 Gene from Tomato Confers Resistance Against Nematodes but Not Aphids in Eggplant

2006 ◽  
Vol 19 (4) ◽  
pp. 383-388 ◽  
Author(s):  
Fiona L. Goggin ◽  
Lingling Jia ◽  
Gowri Shah ◽  
Stephanie Hebert ◽  
Valerie M. Williamson ◽  
...  
Keyword(s):  
Genetic Background ◽  
Meloidogyne Javanica ◽  
Nematode Resistance ◽  
Macrosiphum Euphorbiae ◽  
Leucine Rich Repeat ◽  
Root Knot Nematode ◽  
Potato Aphid ◽  
Tomato Line ◽  
Meloidogyne Spp ◽  
Susceptible Tomato

The Mi-1.2 gene in tomato (Solanum lycopersicum) is a member of the nucleotide-binding leucine-rich repeat (NB-LRR) class of plant resistance genes, and confers resistance against root-knot nematodes (Meloidogyne spp.), the potato aphid (Macrosiphum euphorbiae), and the sweet potato whitefly (Bemisia tabaci). Mi-1.2 mediates a rapid local defensive response at the site of infection, although the signaling and defensive pathways required for resistance are largely unknown. In this study, eggplant (S. melongena) was transformed with Mi-1.2 to determine whether this gene can function in a genetic background other than tomato. Eggplants that carried Mi-1.2 displayed resistance to the root-knot nematode Meloidogyne javanica but were fully susceptible to the potato aphid, whereas a susceptible tomato line transformed with the same transgene was resistant to nematodes and aphids. This study shows that Mi-1.2 can confer nematode resistance in another Solanaceous species. It also indicates that the requirements for Mi-mediated aphid and nematode resistance differ. Potentially, aphid resistance requires additional genes that are not conserved between tomato and eggplant.

scholarly journals Resistance in Peanut Cultivars and Breeding Lines to Three Root-Knot Nematode Species

Plant Disease ◽  
2008 ◽  
Vol 92 (4) ◽  
pp. 631-638 ◽  
Author(s):  
W. B. Dong ◽  
C. C. Holbrook ◽  
P. Timper ◽  
T. B. Brenneman ◽  
Y. Chu ◽  
...  
Keyword(s):  
Durable Resistance ◽  
Nematode Species ◽  
Nematode Resistance ◽  
Root Knot Nematode ◽  
Sources Of Resistance ◽  
Breeding Lines ◽  
Sequence Characterized Amplified Region ◽  
Race 1 ◽  
Meloidogyne Spp ◽  
Peanut Cultivars

Three major species of root-knot nematode infect peanut: Meloidogyne arenaria race 1, M. hapla, and M. javanica race 3. Sources of resistance to all three nematodes are needed for developing novel peanut cultivars with broad resistance to Meloidogyne spp. Cultivars and breeding lines of peanut were evaluated for resistance to M. arenaria, M. hapla, and M. javanica in the greenhouse and in the laboratory. Twenty-six genotypes with some resistance to M. arenaria, M. javanica, or M. hapla were identified from 60 accessions based on average eggs per gram of root and gall index relative to a susceptible control. Among these, 14 genotypes were moderately to highly resistant to all three species, 5 genotypes were resistant to M. arenaria and M. javanica, 2 genotypes were resistant to M. javanica and M. hapla, 1 genotype was resistant M. arenaria alone, and 4 genotypes were resistant to M. hapla alone. Reproduction of M. arenaria on lines NR 0817, C724-19-11, and D108 was highly variable, indicating that these genotypes likely were heterogeneous for resistance. COAN, NemaTAM, C724-25-8, and the M. arenaria-resistant plants of C724-19-11 contained the dominant sequence-characterized amplified region marker (197/909) for nematode resistance. Results with the molecular markers indicate that the high resistance to M. arenaria in GP-NC WS 6 may be different from the resistance in COAN, NemaTAM, and C724-25-8. Resistance to M. arenaria was correlated with resistance to M. javanica in peanut, whereas resistance to M. hapla was not correlated with the resistance to either M. arenaria or M. javanica. The resistant selections should be valuable sources for pyramiding resistance genes to develop new cultivars with broad and durable resistance to Meloidogyne spp.

scholarly journals AFLP and SRAP markers linked to the mj gene for root-knot nematode resistance in cucumber

2011 ◽  
Vol 68 (1) ◽  
pp. 115-119 ◽  
Author(s):  
Zübeyir Devran ◽  
Ahmet Fikret Firat ◽  
Mahmut Tör ◽  
Nedim Mutlu ◽  
Ibrahim Halil Elekçioğlu
Keyword(s):  
Molecular Markers ◽  
Marker Assisted Selection ◽  
Restriction Site ◽  
Nematode Resistance ◽  
Scar Markers ◽  
Root Knot Nematode ◽  
Specific Primers ◽  
Cucumis Sativus L ◽  
Meloidogyne Spp ◽  
Polymorphic Bands

Root-knot nematodes (Meloidogyne spp.) are an important worldwide pest of cucumber (Cucumis sativus L.). Molecular markers linked to the Javanese root-knot nematode (M. javanica) resistance gene mj in cucumber may aid marker assisted selection. One-hundred AFLP (EcoRI-MseI) and 112 SRAP were used to screen resistant and susceptible parents for polymorphisms to develop molecular markers linked to the mj gene. Of the 100 AFLP primers, 92 produced bands and two yielded candidate markers (E-ATT/M-CAA and E-AAC/M-CTG). These two bands were cut off from polyacrylamide gel, cloned and sequenced. Primers designed from the sequences did not yield polymorphic bands between the parents. In addition, the sequences did not contain any restriction site or indel to be used to convert them to CAPS or SCAR markers. The two sequences obtained from polymorphic AFLP markers were used primarily to design D1F, D1R, D17F and D17R primers. SRAP forward and reverse primers were used in combination with these four specific primers to search for polymorphisms between parents. Of the 112 primer combinations 11 yielded polymorphisms between parents. MapMaker Exp 3.0 software was used to analyze the 11 markers. Two markers were identified that flanked the mj gene at distance of 16.3 and 19.3 cM. The results indicated that these markers should be useful to develop molecular markers flanking the mj gene.

scholarly journals Ethylene Signaling Pathway Modulates Attractiveness of Host Roots to the Root-Knot Nematode Meloidogyne hapla

2013 ◽  
Vol 26 (1) ◽  
pp. 75-86 ◽  
Author(s):  
Sylwia L. Fudali ◽  
Congli Wang ◽  
Valerie M. Williamson
Keyword(s):  
Life Cycle ◽  
Signaling Pathway ◽  
Auxin Transport ◽  
Meloidogyne Hapla ◽  
Ethylene Signaling ◽  
Root Knot Nematode ◽  
Synthesis Inhibitor ◽  
Downstream Signaling ◽  
Ethylene Signaling Pathway ◽  
Basipetal Auxin Transport

Infective juveniles of the root-knot nematode Meloidogyne hapla are attracted to the zone of elongation of roots where they invade the host but little is known about what directs the nematode to this region of the root. We found that Arabidopsis roots exposed to an ethylene (ET)-synthesis inhibitor attracted significantly more nematodes than control roots and that ET-overproducing mutants were less attractive. Arabidopsis seedlings with ET-insensitive mutations were generally more attractive whereas mutations resulting in constitutive signaling were less attractive. Roots of the ET-insensitive tomato mutant Never ripe (Nr) were also more attractive, indicating that ET signaling also modulated attraction of root-knot nematodes to this host. ET-insensitive mutants have longer roots due to reduced basipetal auxin transport. However, assessments of Arabidopsis mutants that differ in various aspects of the ET response suggest that components of the ET-signaling pathway directly affecting root length are not responsible for modulating root attractiveness and that other components of downstream signaling result in changes in levels of attractants or repellents for M. hapla. These signals may aid in directing this pathogen to an appropriate host and invasion site for completing its life cycle.

scholarly journals Root-knot Nematode Resistance in Cucumber and Horned Cucumber

HortScience ◽  
1993 ◽  
Vol 28 (2) ◽  
pp. 151-154 ◽  
Author(s):  
S. Alan Walters ◽  
Todd C. Wehner ◽  
Kenneth R. Barkel
Keyword(s):  
Cucumis Sativus ◽  
Nematode Resistance ◽  
Plant Introduction ◽  
Root Knot Nematode ◽  
Root Knot Nematodes ◽  
Breeding Lines ◽  
Meloidogyne Spp ◽  
Race 2 ◽  
Moderately Resistant

Cucumber (Cucumis sativus L.) and horned cucumber (C. metuliferus Naud.) germplasm were evaluated for their resistance to root-knot nematodes (Meloidogyne spp.). All 24 C. metuliferus cultigens evaluated were resistant to all root-knot nematodes tested-M. incognita (Kofoid and White) Chitwood race 3, M. arenaria (Neal) Chitwood race 2, and M. hapla Chitwood. All 884 C. sativus cultigens (cultivars, breeding lines, and plant introduction accessions) tested were resistant to M. hapla and few to M. incognita race 3. Only 50 of 884 C. sativus cultigens evaluated were somewhat resistant to M. arenaria race 2 and M. incognita race 3. A retest of the most resistant C. sativus cultigens revealed that LJ 90430 [an accession of C. sativus var. hardwickii (R.) Alef.] and `Mincu' were the only cultigens that were moderately resistant to M. arenaria race 2. LJ 90430 was the only cultigen, besides the two retested C. metuliferus cultigens, that was resistant to M. javanica (Treub) Chitwood. All C. sativus cultigens retested, including LJ 90430, were highly susceptible to M. incognita races 1 and 3. The two C. metuliferus cultigens retested were highly resistant to all root-knot nematodes tested-M. arenaria race 2, M. incognita races 1 and 3, and M. javanica.

scholarly journals Uncoupling Salicylic Acid-Dependent Cell Death and Defense-Related Responses From Disease Resistance in the Arabidopsis Mutant acd5

Genetics ◽  
2000 ◽  
Vol 156 (1) ◽  
pp. 341-350
Author(s):  
Jean T Greenberg ◽  
F Paul Silverman ◽  
Hua Liang
Keyword(s):  
Cell Death ◽  
Salicylic Acid ◽  
Disease Resistance ◽  
Pseudomonas Syringae ◽  
Higher Plants ◽  
Ethylene Signaling ◽  
Symptom Development ◽  
Wild Type ◽  
Dependent Cell ◽  
Arabidopsis Mutant

Abstract Salicylic acid (SA) is required for resistance to many diseases in higher plants. SA-dependent cell death and defense-related responses have been correlated with disease resistance. The accelerated cell death 5 mutant of Arabidopsis provides additional genetic evidence that SA regulates cell death and defense-related responses. However, in acd5, these events are uncoupled from disease resistance. acd5 plants are more susceptible to Pseudomonas syringae early in development and show spontaneous SA accumulation, cell death, and defense-related markers later in development. In acd5 plants, cell death and defense-related responses are SA dependent but they do not confer disease resistance. Double mutants with acd5 and nonexpressor of PR1, in which SA signaling is partially blocked, show greatly attenuated cell death, indicating a role for NPR1 in controlling cell death. The hormone ethylene potentiates the effects of SA and is important for disease symptom development in Arabidopsis. Double mutants of acd5 and ethylene insensitive 2, in which ethylene signaling is blocked, show decreased cell death, supporting a role for ethylene in cell death control. We propose that acd5 plants mimic P. syringae-infected wild-type plants and that both SA and ethylene are normally involved in regulating cell death during some susceptible pathogen infections.

scholarly journals Transcriptome Analysis of Eggplant Root in Response to Root-Knot Nematode Infection

Pathogens ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 470
Author(s):  
Min Zhang ◽  
Hongyuan Zhang ◽  
Jie Tan ◽  
Shuping Huang ◽  
Xia Chen ◽  
...  
Keyword(s):  
Defense Mechanisms ◽  
Expression Profiles ◽  
Resistance Mechanism ◽  
Solanum Melongena ◽  
Enrichment Analysis ◽  
Nematode Resistance ◽  
Differentially Expressed ◽  
Root Knot Nematode ◽  
Solanum Torvum ◽  
Plant Nematode

Eggplant (Solanum melongena L.), which belongs to the Solanaceae family, is an important vegetable crop. However, its production is severely threatened by root-knot nematodes (RKNs) in many countries. Solanum torvum, a wild relative of eggplant, is employed worldwide as rootstock for eggplant cultivation due to its resistance to soil-borne diseases such as RKNs. In this study, to identify the RKN defense mechanisms, the transcriptomic profiles of eggplant and Solanum torvum were compared. A total of 5360 differentially expressed genes (DEGs) were identified for the response to RKN infection. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis showed that these DEGs are mainly involved in the processes of response to stimulus, protein phosphorylation, hormone signal transduction, and plant-pathogen interaction pathways. Many phytohormone-related genes and transcription factors (MYB, WRKY, and NAC) were differentially expressed at the four time points (ck, 7, 14, and 28 days post-infection). The abscisic acid signaling pathway might be involved in plant-nematode interactions. qRT-PCR validated the expression levels of some of the DEGs in eggplant. These findings demonstrate the nematode-induced expression profiles and provide some insights into the nematode resistance mechanism in eggplant.

scholarly journals The Climatology of Significant Tornadoes in the Czech Republic

Atmosphere ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 689
Author(s):  
Rudolf Brázdil ◽  
Kateřina Chromá ◽  
Tomáš Púčik ◽  
Zbyněk Černoch ◽  
Petr Dobrovolný ◽  
...  
Keyword(s):  
Czech Republic ◽  
Daily Variation ◽  
Convective Available Potential Energy ◽  
Vertical Wind Shear ◽  
Severe Damage ◽  
The Czech Republic ◽  
Annual Variations ◽  
Wide Range ◽  
Individual Trees ◽  
Common Era

In the Czech Republic, tornadoes may reach an intensity of F2 and F3 on the Fujita scale, causing “considerable” to “severe” damage. Documentary evidence is sufficient to allow the creation of a chronology of such events, from the earliest recorded occurrence in 1119 CE (Common Era) to 2019, including a total of 108 proven or probable significant tornadoes on 90 separate days. Since only 11 significant tornadoes were documented before 1800, this basic analysis centers around the 1811–2019 period, during which 97 tornadoes were recorded. Their frequency of occurrence was at its highest in the 1921–1930, 1931–1940, and 2001–2010 decades. In terms of annual variations, they took place most frequently in July, June, and August (in order of frequency), while daily variation favored the afternoon and early evening hours. Conservative estimates of human casualties mention 8 fatalities and over 95 people injured. The most frequent types of damage were related to buildings, individual trees, and forests. Tornadoes of F2–F3 intensity were particularly associated with synoptic types characterized by airflow from the western quadrant together with troughs of low pressure extending or advancing over central Europe. Based on parameters calculated from the ERA-5 re-analysis for the period of 1979–2018, most of these tornadoes occurred over a wide range of Convective Available Potential Energy (CAPE) values and moderate-to-strong vertical wind shear. The discussion herein also addresses uncertainties in tornado selection from documentary data, the broader context of Czech significant tornadoes, and the environmental conditions surrounding their origins.

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