Localization of hydrogen peroxide during the defence response of Arabidopsis thaliana against the plant-parasitic nematode Heterodera glycines

Nematology ◽  
1999 ◽  
Vol 1 (7) ◽  
pp. 681-686 ◽  
Author(s):  
Georg Waetzig ◽  
Miroslaw Sobczak ◽  
Florian Grundler

AbstractHydrogen peroxide (H2O2) production during the infection of Arabidopsis thaliana by the soybean cyst nematode Heterodera glycines was detected histochemically by the reaction of H2O2 with cerium chloride producing four different patterns of electron-dense precipitates of cerium perhydroxides. As A. thaliana is not a regular host of H. glycines, the defence response is considerable, but does not completely inhibit the development of the nematode. H2O2 was produced not only by cells mechanically damaged during invasion and feeding site induction by the nematode, but also by cells surrounding developing syncytia and cells which were neither in contact with the nematode nor with the syncytium. Die Lokalisation von Peroxid wahrend der Abwehrreaktion von Arabidopsis thaliana gegen den pflanzenparasitaren Nematoden Heterodera glycines - Die Bildung von Wasserstoffperoxid (H2O2) im Rahmen der Infektion von Arabidopsis thaliana durch den Sojabohnen-Zystennematoden Heterodera glycines wurde histochemisch durch die Reaktion von H2O2 mit Cerchlorid nachgewiesen, wobei vier verschiedene Muster elektronendichter Prazipitate von Cerperhydroxiden gebildet wurden. Da A. thaliana kein regularer Wirt von H. glycines ist, kommt es zu einer betrachtlichen Abwehrreaktion, die jedoch die Entwicklung des Nematoden nicht vollstandig verhindert. H2O2 wurde nicht nur von Zellen produziert, die im Laufe des Eindringens und der Induktion des Nahrzellensystems durch den Nematoden mechanisch beschadigt worden waren, sondern auch von Zellen, die sich entwickelnde Syncytien umgaben und von Zellen, die weder mit dem Nematoden noch mit dem Syncytium in Kontakt standen.

2018 ◽  
Vol 6 (26) ◽  
Author(s):  
Kurt C. Showmaker ◽  
Kimberly K. O. Walden ◽  
Christopher J. Fields ◽  
Kris N. Lambert ◽  
Matthew E. Hudson

In this study, we present the genome sequence of the “Candidatus Cardinium hertigii” strain cHgTN10, an endosymbiotic bacterium of the plant-parasitic nematode Heterodera glycines. This is the first genome assembly reported for an endosymbiont directly sequenced from a tylenchid nematode.


2014 ◽  
Vol 41 (7) ◽  
pp. 714 ◽  
Author(s):  
Andrea Maldonado ◽  
Reham Youssef ◽  
Margaret McDonald ◽  
Eric Brewer ◽  
Hunter Beard ◽  
...  

Systemic acquired resistance (SAR) is an enhanced defence response triggered when plants detect a pathogen. The response is extended to uninfected organs to protect against future attack. NPR1 is a nuclear leucine-rich repeat protein with a key role in SAR. It binds specifically to salicylic acid, and acts as a transcriptional coregulator of SAR activators and an inhibitor of transcriptional repressors. The proteins encoded by Suppressor of NPR1, Constitutive (SNC1) and Suppressor of NPR1, Inducible (SNI1) interact with NPR1 to regulate the expression of pathogenesis-related genes. The Arabidopsis thaliana (L.) Heynh. snc1 mutant exhibits a constitutive resistance response, but in the sni1 mutant, the SNI1 protein is rendered incapable of suppressing pathogen resistance genes. To study the influence of SNC1 and SNI1 on resistance to the soybean cyst nematode (Heterodera glycines), soybean (Glycine max (L.) Merr.) roots were separately transformed with four constructs designed to: (i) overexpress GmSNC1, the soybean orthologue of AtSNC1; (ii) overexpress AtSNI1; (iii) silence GmSNC1 and (iv) silence GmSNI1. A significant reduction of the female nematode population was observed in Treatments (i) and (iv). The expression of SAR marker genes was analysed in these treatments. The unusual pattern of expression of pathogen resistance genes shows there are differences in the effect resistance genes have on soybean and A. thaliana. Although NPR1 is involved in the cross-talk between the salicylic acid, jasmonic acid and ethylene pathways, understanding the nematode resistance mechanism in plants is still imprecise. These results provide further insights into the soybean defence response.


Agronomy ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 146
Author(s):  
Leonardo F. Rocha ◽  
Karla L. Gage ◽  
Mirian F. Pimentel ◽  
Jason P. Bond ◽  
Ahmad M. Fakhoury

The soybean cyst nematode (SCN; Heterodera glycines Ichinohe) is a major soybean-yield-limiting soil-borne pathogen, especially in the Midwestern US. Weed management is recommended for SCN integrated management, since some weed species have been reported to be hosts for SCN. The increase in the occurrence of resistance to herbicides complicates weed management and may further direct ecological–evolutionary (eco–evo) feedbacks in plant–pathogen complexes, including interactions between host plants and SCN. In this review, we summarize weed species reported to be hosts of SCN in the US and outline potential weed–SCN management interactions. Plants from 23 families have been reported to host SCN, with Fabaceae including most host species. Out of 116 weeds hosts, 14 species have known herbicide-resistant biotypes to 8 herbicide sites of action. Factors influencing the ability of weeds to host SCN are environmental and edaphic conditions, SCN initial inoculum, weed population levels, and variations in susceptibility of weed biotypes to SCN within a population. The association of SCN on weeds with relatively little fitness cost incurred by the latter may decrease the competitive ability of the crop and increase weed reproduction when SCN is present, feeding back into the probability of selecting for herbicide-resistant weed biotypes. Therefore, proper management of weed hosts of SCN should be a focus of integrated pest management (IPM) strategies to prevent further eco–evo feedbacks in the cropping system.


Author(s):  
Kangfu Yu ◽  
Lorna Woodrow ◽  
M. Chun Shi

AAC Richard is a food grade soybean [Glycine max (L.) Merr] cultivar with yellow hilum, high protein concentration, and good processing quality for foreign and domestic soymilk, tofu, and miso markets. It has resistance to SCN (soybean cyst nematode) (Heterodera Glycines Ichinohe). AAC Richard was developed at the Agriculture and Agri-Food Canada (AAFC) Harrow Research and Development Centre (Harrow-RDC), Harrow, Ontario and is adapted to areas of southwest Ontario with 3100 or more crop heat units and has a relative maturity of 2.3 (MG 2.3).


2017 ◽  
Vol 5 (34) ◽  
Author(s):  
Sandeep Sharma ◽  
Alex Z. Zaccaron ◽  
John B. Ridenour ◽  
Amy Bradshaw ◽  
Terry L. Kirkpatrick ◽  
...  

ABSTRACT The taxonomically uncharacterized nematophagous fungus ARF18, which parasitizes cysts, juveniles, and adults of the soybean cyst nematode (Heterodera glycines), was proposed as a nematode biological control agent in 1991. A 46.3-Mb draft genome sequence of this fungus is presented, and a tentative taxonomic identification as a novel species of Brachyphoris is proposed.


2018 ◽  
Author(s):  
Rick Masonbrink ◽  
Tom R. Maier ◽  
Usha Muppiral ◽  
Arun S. Seetharam ◽  
Etienne Lord ◽  
...  

AbstractHeterodera glycines, commonly referred to as the soybean cyst nematode (SCN), is an obligatory and sedentary plant parasite that causes over a billion-dollar yield loss to soybean production annually. Although there are genetic determinants that render soybean plants resistant to certain nematode genotypes, resistant soybean cultivars are increasingly ineffective because their multi-year usage has selected for virulentH. glycinespopulations. The parasitic success ofH. glycinesrelies on the comprehensive re-engineering of an infection site into a syncytium, as well as the long-term suppression of host defense to ensure syncytial viability. At the forefront of these complex molecular interactions are effectors, the proteins secreted byH. glycinesinto host root tissues. The mechanisms of effector acquisition, diversification, and selection need to be understood before effective control strategies can be developed, but the lack of an annotated genome has been a major roadblock. Here, we use PacBio long-read technology to assemble aH. glycinesgenome of 738 contigs into 123Mb with annotations for 29,769 genes. The genome contains significant numbers of repeats (34%), tandem duplicates (18.7Mb), and horizontal gene transfer events (151 genes). Using previously published effector sequences, the newly generatedH. glycinesgenome, and comparisons to other nematode genomes, we investigate the evolutionary mechanisms responsible for the emergence and diversification of effector genes.


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