scholarly journals Continuous Monoculture Shapes Root and Rhizosphere Fungal Communities of Corn and Soybean in Soybean Cyst Nematode-Infested Soil

2019 ◽  
Vol 3 (4) ◽  
pp. 300-314 ◽  
Author(s):  
Noah Strom ◽  
Weiming Hu ◽  
Senyu Chen ◽  
Kathryn Bushley
Keyword(s):  
Relative Abundance ◽  
Soybean Cyst Nematode ◽  
Arbuscular Mycorrhizal ◽  
Cyst Nematode ◽  
Fungal Communities ◽  
Corn Yield ◽  
Infested Soil ◽  
Plant Soil ◽  
Continuous Corn ◽  
Continuous Monoculture

The rhizosphere effect shapes microbial communities around and within plant roots and may lead to the enrichment of fungi involved in both positive and negative plant-soil feedbacks. We used internal transcribed spacer 1 amplicon sequencing to investigate how continuous monoculture affects the fungal communities in the corn and soybean rhizosphere, rhizoplane, and root endosphere in a long-term crop rotation experiment where soils were infested with a major soybean pathogen, the soybean cyst nematode (SCN, Heterodera glycines). Community-level statistical analyses showed evidence of selective filtering and enrichment of fungi in and around corn and soybean roots and in SCN cysts. Patterns of relatedness between fungal communities in various agroecosystem compartments suggested that SCN cysts are colonized by soybean root endophytic fungi and that colonization of roots and cysts may aid proliferation of these fungi in the bulk soil agroecosystem compartment over time. Natural antagonists of the SCN such as nematode-trapping fungi and nematode endoparasites increased in relative abundance in the rhizosphere and root endosphere, respectively, over continuous soybean monoculture. In contrast, arbuscular mycorrhizal and plant-pathogenic fungi, several of which were negatively correlated with corn yield, increased in relative abundance over continuous corn monoculture. These results suggest the possibility of positive plant-soil feedbacks involving nematophagous fungi over continuous soybean monoculture and negative plant-soil feedbacks involving plant pathogens and some nonbeneficial arbuscular mycorrhizal fungi over continuous corn monoculture.

scholarly journals Fungal Communities in Soybean Cyst Nematode-Infested Soil under Long Term Corn and Soybean Monoculture and Crop Rotation

2019 ◽  
Author(s):  
Noah Strom ◽  
Weiming Hu ◽  
Deepak Haarith ◽  
Senyu Chen ◽  
Kathryn Bushley
Keyword(s):  
Soil Properties ◽  
Crop Rotation ◽  
Relative Abundance ◽  
Soybean Cyst Nematode ◽  
Abiotic Factors ◽  
Cyst Nematode ◽  
Fungal Communities ◽  
Infested Soil ◽  
Crop Sequence

AbstractCorn (Zea mays) and soybean (Glycine max) production forms an integral part of economies worldwide, but yields are limited by biotic and abiotic factors associated with short rotations and long-term monocultures. In this study, a long-term rotation study site with corn and soybean planted in annual rotation, five-year rotation, and long-term monoculture was utilized to examine the relationships between crop sequences, soil fungal communities, soybean cyst nematode (SCN, Heterodera glycines) densities, soil properties, and crop yields. High throughput sequencing of the ITS1 region of fungal rDNA revealed that soil fungal community structure varied significantly by crop sequence, with fungal communities under five consecutive years of monoculture becoming progressively similar to communities in long-term monoculture plots associated with their respective crop hosts. Total alpha diversity was greater under corn, but patterns of diversity and relative abundance of specific functional groups differed by crop host, with more pathotrophs proliferating under soybean and more saprotrophs and symbiotrophs proliferating under corn. Soil phosphorus (P) varied significantly by crop sequence, with lower levels of P corresponding with relative abundance of Glomerales, Paraglomerales, and Sebacinales and higher levels of P corresponding with relative abundance of Mortierellales. Soil density of the SCN was positively correlated with relative abundance and diversity of nematode-trapping fungi and with relative abundance of many potential nematode egg parasites. These results suggest several possible explanations for the improved yields associated with crop rotation, including decreased pathogen pressure, modification of soil properties, and increased diversity of soil fungal communities. Future research should investigate the potential of nematode-trapping fungi to regulate SCN densities and examine the relationships between soil P and specific arbuscular mycorrhizal and mortierellalean fungi associated with corn and soybean hosts.

scholarly journals Divergence in bidirectional plant-soil feedbacks between montane annual and coastal perennial ecotypes of yellow monkeyflower (Mimulus guttatus)

2020 ◽  
Author(s):  
Mariah M. McIntosh ◽  
Lorinda Bullington ◽  
Ylva Lekberg ◽  
Lila Fishman
Keyword(s):  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizal ◽  
Plant Performance ◽  
Fungal Communities ◽  
Mechanistic Study ◽  
List Type ◽  
Mimulus Guttatus ◽  
Plant Variation ◽  
Plant Soil ◽  
Soil Origin

SUMMARYUnderstanding the physiological and genetic mechanisms underlying plant variation in interactions with root-associated biota (RAB) requires a micro-evolutionary approach. We use locally adapted montane annual and coastal perennial ecotypes of Mimulus guttatus (yellow monkeyflower) to examine population-scale differences in plant-RAB-soil feedbacks.We characterized fungal communities for the two ecotypes in-situ and used a full-factorial greenhouse experiment to investigate the effects of plant ecotype, RAB source, and soil origin on plant performance and endophytic root fungal communities.The two ecotypes harbored different fungal communities and responsiveness to soil biota was highly context-dependent. Soil origin, RAB source, and plant ecotype all affected the intensity of biotic feedbacks on plant performance. Feedbacks were primarily negative, and we saw little evidence of local adaptation to either soils or RAB. Both RAB source and soil origin significantly shaped fungal communities in roots of experimental plants. Further, the perennial ecotype was more colonized by arbuscular mycorrhizal fungi (AMF) than the montane ecotype, and preferentially recruited home AMF taxa.Our results suggest life history divergence and distinct edaphic habitats shape plant responsiveness to RAB and influence specific associations with potentially mutualistic root endophytic fungi. Our results advance the mechanistic study of intraspecific variation in plant–soil–RAB interactions.

Nematicidal activity of ethanol solutions on soybean cyst nematode Heterodera glycines

Nematology ◽  
2019 ◽  
Vol 22 (1) ◽  
pp. 111-121
Author(s):  
Luma A. Pedroso ◽  
Vicente P. Campos ◽  
Aline F. Barros ◽  
Julio C.P. Silva ◽  
Gustavo M. Assis ◽  
...  
Keyword(s):  
Lipid Content ◽  
Sustainable Management ◽  
Soybean Cyst Nematode ◽  
Management Practices ◽  
Heterodera Glycines ◽  
Cyst Nematode ◽  
Infested Soil ◽  
Tropical Regions ◽  
Second Stage ◽  
Low Concentrations

Summary The cyst nematode, Heterodera glycines, is a major pathogen of soybean in tropical regions, which demands novel sustainable management practices. In this work, the use of ethanol against H. glycines was evaluated as both a solution and a fumigant. On second-stage juveniles (J2) of H. glycines, ethanol at low concentration was more effective by direct dipping than by only fumigating the J2. Hatching was significantly reduced by direct dipping in ethanol solutions. Fumigation of H. glycines-infested soil with ethanol reduced infectivity by almost 100% and the number of eggs by about 67% at ethanol concentrations of 48% and 72%, respectively. Only the ethanol at 48% concentration significantly reduced the J2 lipid content, while J2 infectivity and the number of eggs were reduced by dipping at 6% ethanol. The J2 were internally altered by the ethanol solutions. Therefore, ethanol is toxic to H. glycines at low concentrations and affects its pathogenic behaviour rather than simply reducing the lipids.

Soybean cyst nematode: Challenges and opportunities

2006 ◽  
Vol 86 (1) ◽  
pp. 25-32 ◽  
Author(s):  
Shawn M. J Winter ◽  
Istvan Rajcan ◽  
Barry J Shelp
Keyword(s):  
Resistance Genes ◽  
Soybean Cyst Nematode ◽  
Glycine Soja ◽  
Cyst Nematode ◽  
Infested Soil ◽  
Linkage Groups ◽  
Factors Affecting ◽  
Scn Resistance ◽  
Major Resistance Genes ◽  
Time Required

Soybean cyst nematode (SCN) is the primary pest responsible for yield losses of Glycine max. Management of SCN remains difficult in commercial soybean production due to the length of its biological cycle, frequent changes in population virulence, and ease of spread via infested soil. Effective management relies on crop rotation in combination with resistant cultivars, which have been derived from a limited germplasm base. Breeding for SCN resistance in soybean is difficult due to the quantitative nature of the trait, genetic variation within SCN populations, time required for phenotyping experimental soybean lines, and environmental factors affecting SCN reproduction. Quantitative trait loci associated with SCN resistance have been identified on 17 of the 20 soybean linkage groups, explaining 1–91% of the total phenotypic variation. Two major resistance genes, rhg 1 and Rhg 4, have been identified on linkage groups G and A2, respectively. Several minor resistance genes have been identified, but their importance varies with germplasm source and nematode race. Enhancement of SCN resistance in G. max may be achieved by interspecific hybridization with G. soja, the wild ancestor, or by engineering plants with candidate resistance genes such as Hs1pro-1. Key words: Genetic engineering, Glycine soja, soybean cyst nematode, molecular markers, resistance

scholarly journals Use of the Glomus etunicatum as biocontrol agent of the soybean cyst nematode

2021 ◽  
Vol 10 (6) ◽  
pp. e7310615132
Author(s):  
Tatiana Benedetti ◽  
Zaida Inês Antoniolli ◽  
Elisangela Sordi ◽  
Ivan Ricardo Carvalho ◽  
Edson Campanhola Bortoluzzi
Keyword(s):  
Soybean Cyst Nematode ◽  
Mycorrhizal Fungus ◽  
Arbuscular Mycorrhizal ◽  
Cyst Nematode ◽  
Initial Population ◽  
Glomus Etunicatum ◽  
Cyst Nematodes ◽  
Nematode Reproduction ◽  
Soybean Plants ◽  
Disease Pressure

This study investigated the effect of arbuscular mycorrhiza (Glomus etunicatum Becker & Gerd.), on the cyst nematode (Heterodera glycines Ichinohe), in a greenhouse. Mycorrhizal and non-mycorrhizal soybean plants were exposed to the pathogen at different initial population densities (0, 500, 1000, 2000, and 4000 nematodes eggs). Soybean growth, nematode reproduction, and the arbuscular mycorrhizal fungus’s capacity to decrease disease pressure were determined after 60 day-olds. The height of the plants was increased by 26% in the presence of arbuscular mycorrhizal fungus (AMF) despite of a higher initial population of cyst nematodes. The root length was, on average, 32.20% was greater in the presence of AMF. The number of nematodes females found in the root system of mycorrhizal plants was 28.21% lower than in non-mycorrhizal roots. These results suggest that AMF G. etunicatum acts indirectly, promoting an improvement in the nutritional plant status creating tolerance to the presence of the pathogen by soybean.

scholarly journals First Report of Soybean Cyst Nematode (Heterodera glycines) on Soybean in Puerto Rico

Plant Disease ◽  
1999 ◽  
Vol 83 (6) ◽  
pp. 591-591
Author(s):  
J. R. Smith ◽  
J. A. Chavarria-Carvajal
Keyword(s):  
Puerto Rico ◽  
Common Bean ◽  
Soybean Cyst Nematode ◽  
Heterodera Glycines ◽  
Pigeon Pea ◽  
Cyst Nematode ◽  
Research Field ◽  
Growth Stages ◽  
Infested Soil ◽  
Infested Field

Soybean (Glycine max (L.) Merr.) winter nurseries have been planted in Puerto Rico at the USDA's Isabela farm for 25 consecutive years. The field has had one soybean crop each year, with a summer fallow period between winter nursery seasons. In February 1998, during an inspection of root nodulation, cysts were discovered on roots of an F2 population (Benning × Pureunkong). Microscopic examination of roots confirmed the presence of female nematodes of Heterodera glycines Ichinohe in various stages of development. No cysts were found when soil and roots were randomly sampled at various growth stages (R1 to R7) from other soybean fields in Puerto Rico (Isabela, Salinas, Lajas, and Juana Diaz). Also, no cysts were observed on roots of common bean (Phaseolus vulgaris) at growth stages R7 to R8 in a neighboring research field. However, cysts were observed on 35-day-old roots of soybean cv. Lee, common bean, and pigeon pea (Cajanas cajun) grown in the above infested soil. A race assay, slightly modified from standard protocols (3), determined that the infested soil contained race 2 of H. glycines. The infested field was rotated to sorghum during the summer of 1998 and then soybeans were planted in the 1998-1999 winter nursery. H. glycines occurs in at least 26 states of the U.S., and in Canada, Asia, and South America (1,2). References: (1) M. L. Mendes and D. W. Dickson. Plant Dis. 77:499, 1993. (2) R. D. Riggs and D. P. Schmitt. 1989. Soybean Cyst Nematode. Page 65 in: Compendium of Soybean Diseases. 3rd ed. J. B. Sinclair and P. A. Backman, eds. American Phytopathological Society, St. Paul, MN. (3) D. P. Schmitt and G. Shannon. Crop Sci. 32:275, 1992.

Assessing direct and residual effects of cover crops on the soybean cyst nematode, Heterodera glycines

Plant Disease ◽  
2021 ◽  
Author(s):  
Chelsea J. Harbach ◽  
Gregory L. Tylka
Keyword(s):  
Cover Crops ◽  
Cover Crop ◽  
Soybean Cyst Nematode ◽  
Heterodera Glycines ◽  
Cyst Nematode ◽  
Residual Effects ◽  
Infested Soil ◽  
Annual Ryegrass ◽  
Population Densities ◽  
Crimson Clover

Greenhouse experiments were conducted to determine if cover crops directly decrease population densities of the soybean cyst nematode (SCN), Heterodera glycines, and/or have residual effects on reproduction of the nematode on soybean (Glycine max). Population densities of SCN were not significantly decreased by nine cover crop plants or three cover crop mixes compared to a non-planted soil control in a repeated 60-day-long greenhouse experiment. When susceptible soybeans were grown in the soils after cover crop growth, fewer SCN females formed following three annual ryegrass (Lolium multiflorum) cultivars (Bounty, King, and RootMax), the Daikon radish (Raphanus sativus var. longipinnatus) cultivar CCS779, Kodiak mustard (Brassica juncea), and a mix containing cereal rye, crimson clover (Trifolium incarnatum), plus Daikon radish (cultivars not stated) compared to following the non-planted control. In another repeated experiment, cover crops were grown for 56 days in SCN-infested soil in the greenhouse then exposed to Iowa winter conditions for 28 days to simulate winter termination of the plants. One treatment, a cover crop mix containing Bounty annual ryegrass plus Enricher Daikon radish, had a decrease in SCN population density greater than the non-planted control at the end of the experiment. Significantly fewer SCN females formed on soybeans grown following several cover crops, including the three annual ryegrass cultivars that had the suppressive residual effects in the first experiment. In summary, there were no cover crop treatments that consistently decreased SCN population densities across experiments, and only one cover crop treatment in one experiment significantly reduced SCN population densities more than a non-planted soil control. However, there was a somewhat consistent, adverse, residual effect of cover crops on reproduction of SCN on susceptible soybeans following growth of multiple cover crops.

scholarly journals Interactive Effects of Soybean Cyst Nematode, Arbuscular-mycorrhizal Fungi, and Soil pH on Chlorophyll Content and Plant Growth of Soybean

2021 ◽  
Author(s):  
Manhong Sun ◽  
Senyu Chen ◽  
James E. Kurle
Keyword(s):  
Population Density ◽  
Plant Growth ◽  
Soil Ph ◽  
Mycorrhizal Fungi ◽  
Soybean Cyst Nematode ◽  
Arbuscular Mycorrhizal ◽  
Cyst Nematode ◽  
Interactive Effects ◽  
High Ph ◽  
Shoot Weight

Nutritional deficiency chlorosis especially iron-deficiency chlorosis and soybean cyst nematode (SCN) limit soybean yield. Arbuscular mycorrhizal fungi (MF) generally have beneficial effects on plant growth. The interactive effects of SCN, MF, and soil pH on leaf chlorophyll content (LCC) and growth of soybean were examined in a greenhouse experiment. The experiment was a randomized complete block design with three factors: SCN population densities, MF inoculation, and soil pH levels. SCN reduced LCC, and the effect increased with increasing time during 5-9 weeks after planting, especially in the high pH (8) soil. MF increased LCC in low pH (5.6) soil regardless of SCN population density and in the high pH soil without SCN. However, MF reduced LCC if both pH and SCN population density were high. The high SCN population density (inoculation 10,000 eggs/100 cm3 soil) reduced soybean shoot weight in all soils regardless of MF. MF increased shoot weight at pH 6.9 and pH 8 but not at pH 5.6. When MF was present, shoot weight was generally highest at pH 6.9. At high SCN when MF was absent, plant growth was better in pH 5.6 than pH 6.9 and 8 soils. This study demonstrates that SCN causes greater damage to soybean when interacting with high pH, and MF had a beneficial effect on soybean growth regardless of SCN infection in all pH soils, in spite of the negative effect of MF on LCC around 5-9 weeks after planting in high pH soil at high SCN population density.

Sign in / Sign up

Export Citation Format

Share Document