scholarly journals Genetic Analysis of Parasitism in the Soybean Cyst Nematode Heterodera glycines

Genetics ◽  
1997 ◽  
Vol 146 (4) ◽  
pp. 1311-1318 ◽  
Author(s):  
Ke Dong ◽  
Charles H Opperman

A genetic analysis of parasitic ability in the soybean cyst nematode Heterodera glycines was performed. To identify and characterize genes involved in parasitism, we developed three highly inbred H. glycines lines, OP20, OP25 and OP50, for use as parents for controlled crosses. Through these crosses, we have identified genes in the inbred parents that control reproduction of the nematode on hosts that carry resistance genes. These genes, designated as ror-* for reproduction on a resistant host, segregate in a normal Mendelian fashion as independent loci. Host range tests of F1 generation progeny indicated that at least one parasitism gene in both the OP20 and OP50 lines for host PI 88788 was dominant. Parasitism genes in OP50 for hosts “Peking” and PI 90763 are recessive. Two types of single female descent populations, a single backcrossed BC1F2-derived and a double backcrossed BC2F1-derived, were established on the susceptible soybean cultivar “Lee 68.” Host range tests for parasitism in these lines demonstrated the presence of two independent genes in OP50, one for host PI 88788 designated ror-1 and one for host PI 90763 designated ror-2. OP20 carries two independent genes for parasitism on PI 88788, designated as alleles kr3 and kr4.

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.


Plant Disease ◽  
2007 ◽  
Vol 91 (11) ◽  
pp. 1473-1476 ◽  
Author(s):  
Melissa G. Mitchum ◽  
J. Allen Wrather ◽  
Robert D. Heinz ◽  
J. Grover Shannon ◽  
Gene Danekas

The soybean cyst nematode, Heterodera glycines, is a serious economic threat to soybean producers in Missouri. Periodic monitoring for the presence, population densities, and virulence phenotypes of H. glycines is essential for determining crop losses and devising management strategies implementing the use of resistant cultivars. A survey using area-frame sampling was conducted to determine the distribution and virulence phenotypes of H. glycines in Missouri during 2005. Two samples from each of 125 fields representing eight geographical regions of Missouri were collected; 243 samples were processed for extraction of cysts and eggs. In all, 49% of samples had detectable cyst nematode populations, which ranged from 138 to 85,250 eggs per 250 cm3 of soil. Race and H. glycines type tests were conducted on populations from 45 samples. Nearly 80% of the populations that were tested, irrespective of the region, were virulent on the indicator line plant introduction (PI) 88788, which is the source of resistance for most H. glycines-resistant cultivars. More than 70% of populations could reproduce on the indicator lines PI 88788, PI 209332, and PI 548316 (Cloud), indicating that soybean cultivars with resistance derived from these sources need to be carefully monitored and used only in rotation with nonhost crops and soybean cultivars with resistance from other sources. Approximately one-third of the populations, primarily in the southern regions of Missouri, could reproduce on PI 548402 (Peking), another common source of resistance. Fewer than 10% of the populations could reproduce on PI 90763, PI 437654, PI 89772, or PI 438489B, suggesting that these sources of resistance should be used in soybean breeding programs to develop H. glycines-resistant soybean cultivars.


Plant Disease ◽  
2004 ◽  
Vol 88 (11) ◽  
pp. 1287-1287 ◽  
Author(s):  
C. A. Bradley ◽  
C. R. Biller ◽  
B. D. Nelson

During August 2003, soybean (Glycine max) plants from Richland County, North Dakota with white-to-yellow, lemon-shaped structures on the roots were brought to the North Dakota State University Plant Diagnostic Laboratory. To confirm that the structures were females of a cyst nematode, they were crushed and observed microscopically to determine if nematode eggs and second-stage juveniles were present. Morphology of the second-stage juveniles was consistent with Heterodera glycines, the soybean cyst nematode (SCN). A survey was conducted in soybean fields in 34 km2 around the field in which the samples originated. Ten of twenty fields surveyed had visible females on the roots of plants. Symptoms observed in those fields included patches of stunted, chlorotic, and dead plants. Soil samples were collected from selected areas within eight fields, eggs were extracted using standard soil sieving techniques, and egg numbers were determined. Egg numbers ranged from 550 to 20,000 eggs per 100 cm3 of soil. SCN collected from two different fields, designated as Dwight and LaMars, were used to determine their HG Type. Standardized procedures (1) were used in a growth chamber set at 27°C with 16-h days. Pots in the test were organized in a completely randomized design with three replicates; the test was repeated over time. After 30 days, females were extracted from roots and counted, and a female index (FI) was calculated for each indicator line (1). The mean number of females on susceptible standard cv. Lee 74, was 110. The Dwight SCN population had an FI of 5.3 on plant introduction (PI) 88788, 1.5 on PI 209332, 5.8 on PI 548316 (Cloud), and 0 on all other indicator lines. The LaMars population had an FI of 1.0 on PI 88788, 3.1 on PI 548316 (Cloud), and 0 on all other indicator lines. These results indicate that both SCN populations tested are HG Type 0. To our knowledge, this is the first report of SCN on soybean in North Dakota. Because other hosts of SCN, as well as soybean, are economically important in North Dakota, such as dry edible bean (Phaseolus vulgaris) and dry pea (Pisum sativum), this disease could adversely impact several commodities throughout the state. Reference: (1) T. L. Niblack et al. J. Nematol. 34:279, 2002.


BMC Genomics ◽  
2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Rick Masonbrink ◽  
Tom R. Maier ◽  
Usha Muppirala ◽  
Arun S. Seetharam ◽  
Etienne Lord ◽  
...  

Plant Disease ◽  
2017 ◽  
Vol 101 (12) ◽  
pp. 2137-2143 ◽  
Author(s):  
Yuba R. Kandel ◽  
Kiersten A. Wise ◽  
Carl A. Bradley ◽  
Martin I. Chilvers ◽  
Adam M. Byrne ◽  
...  

A three-year study was conducted in Illinois, Indiana, Iowa, Michigan, and Ontario, Canada, from 2013 through 2015 to determine the effect of soybean (Glycine max) cultivars’ source of soybean cyst nematode (SCN; Heterodera glycines) resistance on SCN population densities, sudden death syndrome (SDS; caused by Fusarium virguliforme), and yield of soybean. Five cultivars were evaluated with and without fluopyram seed treatment at each location. Cultivars with no SCN resistance had greater SDS severity, greater postharvest SCN egg counts (Pf), and lower yield than cultivars with plant introduction (PI) 548402 (Peking) and PI 88788-type of SCN resistance (P < 0.05). Cultivars with Peking-type resistance had lower Pf than those with PI 888788-type and no SCN resistance. In two locations with HG type 1.2-, cultivars with Peking-type resistance had greater foliar disease index (FDX) than cultivars with PI 88788-type. Fluopyram seed treatment reduced SDS and improved yield compared with a base seed treatment but did not affect SCN reproduction and Pf (P > 0.05). FDX and Pf were positively correlated in all three years (P < 0.01). Our results indicate that SDS severity may be influenced by SCN population density and HG type, which are important to consider when selecting cultivars for SCN management.


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.


Sign in / Sign up

Export Citation Format

Share Document