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Frankenstein D, Luu MS, Luna-Ayala J, Willett DS, Filgueiras CS. Soil moisture conditions alter behavior of entomopathogenic nematodes. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2024; 104:4383-4390. [PMID: 38323469 DOI: 10.1002/jsfa.13326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 01/20/2024] [Accepted: 01/22/2024] [Indexed: 02/08/2024]
Abstract
BACKGROUND A variety of environmental factors can disrupt biotic interactions between plants, insects and soil microorganisms with consequences for agricultural management and production. Many of these belowground interactions are mediated by volatile organic compounds (VOCs) which can be used for communication under appropriate environmental conditions. Behavioral responses to these compounds may likewise be dependent on varying soil conditions which are influenced by a changing climate. To determine how changing environmental conditions may affect VOC-mediated biotic interactions, we used a belowground system where entomopathogenic nematodes (EPNs) - tiny roundworm parasitoids of soil-borne insects - respond to VOCs by moving through the soil pore matrix. Specifically, we used two genera of EPNs - Heterorhabditis and Steinernema - that are known to respond to four specific terpenes - α-pinene, linalool, d-limonene and pregeijerene - released by the roots of plants in the presence of herbivores. We assessed the response of these nematodes to these terpenes under three moisture regimes to determine whether drier conditions or inundated conditions may influence the response behavior of these nematodes. RESULTS Our results illustrate that the recovery rate of EPNs is positively associated with soil moisture concentration. As soil moisture concentration increases from 6% to 18%, substantially more nematodes are recovered from bioassays. In addition, we find that soil moisture influences EPN preference for VOCs, as illustrated in the variable response rates. Certain compounds shifted from acting as a repellent to acting as an attractant and vice versa depending on the soil moisture concentration. CONCLUSION On a broad scale, we demonstrate that soil moisture has a significant effect on EPN host-seeking behavior. EPN efficacy as biological control agents could be affected by climate change projections that predict varying soil moisture concentrations. We recommend that maintaining nematodes as biological control agents is essential for sustainable agriculture development, as they significantly contribute not only to soil health but also to efficient pest management. © 2024 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
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Affiliation(s)
- Dana Frankenstein
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN, USA
| | - Macawan S Luu
- Department of Mathematics and Statistics, University of Maryland Baltimore County, College Park, MD, USA
| | - Jennifer Luna-Ayala
- Department of Biology, University of North Carolina Asheville, Asheville, NC, USA
| | - Denis S Willett
- North Carolina Institute for Climate Studies, North Carolina State University, Raleigh, NC, USA
| | - Camila S Filgueiras
- Department of Biology, University of North Carolina Asheville, Asheville, NC, USA
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Baniya A, Subkrasae C, Ardpairin J, Anesko K, Vitta A, Dillman AR. STEINERNEMA ADAMSI N. SP. (RHABDITIDA: STEINERNEMATIDAE), A NEW ENTOMOPATHOGENIC NEMATODE FROM THAILAND. J Parasitol 2024; 110:22-39. [PMID: 38334188 DOI: 10.1645/23-60] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2024] Open
Abstract
A new species of entomopathogenic nematode, Steinernema adamsi n. sp., was recovered from the soil of a longan tree (Dimocarpus sp.) in Mueang Lamphun District, Thailand, using baiting techniques. Upon analysis of the nematode's morphological traits, we found it to be a new species of Steinernema and a member of the Longicaudatum clade. Molecular analyses of the ITS rDNA and D2D3 of 28S rDNA sequences further confirmed that S. adamsi n. sp. is a new species of the Longicaudatum clade, which is closely related to Steinernema guangdongense and Steinernema longicaudam. Using morphometric analysis, the infective juveniles measure between 774.69 and 956.96 μm, males have a size range of 905.44 to 1,281.98 μm, and females are within the range of 1,628.21 to 2,803.64 μm. We also identified the symbiotic bacteria associated with the nematode based on 16S sequences as Xenorhabdus spp. closely related toXenorhabdus griffiniae. Furthermore, we have successfully assessed a cryopreservation method for the long-term preservation of S. adamsi n. sp. Successful cryopreservation of this new species will allow for the longer preservation of its traits and will be valuable for its future use. The discovery of this new species has significant implications for the development of effective biological control agents in Thailand, and our work contributes to our understanding of the diversity and evolution of entomopathogenic nematodes.
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Affiliation(s)
- Anil Baniya
- Department of Nematology, University of California, Riverside, California 92521
| | - Chanakan Subkrasae
- Department of Microbiology and Parasitology, Faculty of Medical Science, Naresuan University, Phitsanulok 65000, Thailand
| | - Jiranun Ardpairin
- Department of Microbiology and Parasitology, Faculty of Medical Science, Naresuan University, Phitsanulok 65000, Thailand
| | - Kyle Anesko
- Department of Nematology, University of California, Riverside, California 92521
| | - Apichat Vitta
- Department of Microbiology and Parasitology, Faculty of Medical Science, Naresuan University, Phitsanulok 65000, Thailand
- Centre of Excellence for Biodiversity, Faculty of Sciences, Naresuan University, Phitsanulok 65000, Thailand
| | - Adler R Dillman
- Department of Nematology, University of California, Riverside, California 92521
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Filgueiras CC, Willett DS. Non-lethal effects of entomopathogenic nematode infection. Sci Rep 2021; 11:17090. [PMID: 34429457 PMCID: PMC8384869 DOI: 10.1038/s41598-021-96270-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 08/04/2021] [Indexed: 11/10/2022] Open
Abstract
Entomopathogenic nematodes are typically considered lethal parasites of insect hosts. Indeed they are employed as such for biological control of insect pests. The effects of exposure to entomopathogenic nematodes are not strictly limited to mortality, however. Here we explore non-lethal effects of exposure to entomopathogenic nematodes by introducing the relatively non-susceptible pupal stage of Delia antiqua to thirteen different strains. We specifically chose to inoculate the pupal stage because it tends to be more resistant to infection, yet resides in the soil where it could come into contact with EPN biological control agents. We find that there is no significant mortality at the pupal stage, but that there are a host of strain-dependent non-lethal effects during and after the transition to adulthood including altered developmental times and changes in risk of death compared to controls. We also find that exposure to specific strains can reduce risk of mortality. These results emphasize the strain-dependent nature of entomopathogenic nematode infection and highlight the positive and negative ramifications for non-lethal effects for biological control of insect pests. Our work emphasizes the need for strain-specific screening of biological control agents before wide-spread adoption.
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Affiliation(s)
- Camila C Filgueiras
- Natural Enemy Management and Applications (NEMA) Lab, Department of Biology, UNC Asheville, Asheville, USA.
| | - Denis S Willett
- Applied Chemical Ecology Technology (ACET) Lab, Cornell AgriTech, Cornell University, Ithaca, USA
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Baniya A, DiGennaro P. Genome announcement of Steinernema khuongi and its associated symbiont from Florida. G3 (BETHESDA, MD.) 2021; 11:6149128. [PMID: 33624756 PMCID: PMC8049438 DOI: 10.1093/g3journal/jkab053] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 02/03/2021] [Indexed: 01/15/2023]
Abstract
Citrus root weevil (Diaprepes abbreviates) causes significant yield loss in citrus, especially in Florida. A promising source of control for this pest is biological control agents, namely, native entomopathogenic nematodes (EPNs) within the genus Steinernema. Two species of endemic EPN in Florida are S. diaparepesi, abundant within the central ridge, and S. khuongi, dominating the flatwood regions of the state. These citrus-growing regions differ significantly in their soil habitats, which impacts the potential success of biological control measures. Although the genome sequence of S. diaprepesi is currently available, the genome sequence of S. khuongi and identity of the symbiotic bacteria is still unknown. Understanding the genomic differences between these two nematodes and their favored habitats can inform successful biological control practices. Here, MiSeq libraries were used to simultaneously sequence and assemble the draft genome of S. khuongi and its associated symbionts. The final draft genome for S. khuongi has 8,794 contigs with a total length of ∼82 Mb, a largest contig of 428,226 bp, and N50 of 46 kb; its BUSCO scores indicate that it is > 86% complete. An associated bacterial genome was assembled with a total length of ∼3.5 Mb, a largest contig at 116,532 bp, and N50 of 17,487 bp. The bacterial genome encoded 3,721 genes, similar to other Xenorhabdus genomes. Comparative genomics identified the symbiotic bacteria of S. khuongi as Xenorhabdus poinarii. These new draft genomes of a host and symbiont can be used as a valuable tool for comparative genomics with other EPNs and its symbionts to understand host range and habitat suitability.
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Affiliation(s)
- Anil Baniya
- Department of Entomology and Nematology, University of Florida, Gainesville, FL 32611, USA
| | - Peter DiGennaro
- Department of Entomology and Nematology, University of Florida, Gainesville, FL 32611, USA
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Baniya A, Huguet-Tapia JC, DiGennaro P. A draft genome of Steinernema diaprepesi. J Nematol 2020; 52:1-4. [PMID: 32678527 PMCID: PMC8015292 DOI: 10.21307/jofnem-2020-069] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Indexed: 12/02/2022] Open
Abstract
Entomopathogenic nematodes within the genus Steinernema are used as biological control agents against significant agricultural pests. Steinernema diaprepesi is native to Florida and very effective in controlling citrus root weevil, a devastating pest of citrus, ornamental plants, and vegetables. Here, we present the draft genome of Steinernema diaprepesi, which is a valuable tool for understanding the efficacy of this nematode as a biological control agent.
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Affiliation(s)
- Anil Baniya
- Department of Entomology and Nematology, University of Florida , Gainesville FL, 32611
| | - Jose C Huguet-Tapia
- Department of Entomology and Nematology, University of Florida , Gainesville FL, 32611
| | - Peter DiGennaro
- Department of Entomology and Nematology, University of Florida , Gainesville FL, 32611
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Sandhi RK, Pothula R, Pothula SK, Adams BJ, Reddy GVP. First record of native entomopathogenic nematodes from Montana agroecosystems. J Nematol 2020; 52:1-11. [PMID: 32628826 PMCID: PMC7366840 DOI: 10.21307/jofnem-2020-060] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Indexed: 11/29/2022] Open
Abstract
A total of 30 different agricultural fields in the Golden Triangle Region of Montana, USA were surveyed, and 150 soil samples were evaluated for the presence of entomopathogenic nematodes (EPNs). The authors isolated EPNs from 10% of the collected samples. The recovered isolates were identified as Steinernema feltiae and Heterorhabditis bacteriophora by using morphological and molecular analysis. Steinernema feltiae was found from two fields, Kalispell (S. feltiae 1) and Choteau (S. feltiae 2). Steinernema feltiae (1 and 2) differed significantly from each other in terms of morphological characters for infective juveniles (distance from anterior end to excretory pore and nerve ring) and 1st generation males (body length, spicule length, gubernaculum length, oesophagus, tail, and anal body diameter). Steinernema feltiae 2 and H. bacteriophora were recovered from the same field in Choteau. All these species were recovered from wheat fields with sandy clay loam and loam soils with 3.3 to 3.4% organic matter content and pH 8.
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Affiliation(s)
- Ramandeep K Sandhi
- Department of Research Centers, Western Triangle Agricultural Research Center, Montana State University , 9546 Old Shelby Rd., P.O. Box 656, Conrad, MT 59425
| | - Ratnasri Pothula
- Department of Biology, Monte L. Bean Museum, and Evolutionary Ecology Laboratories, Brigham Young University , Provo, UT 84602
| | - Satyendra K Pothula
- Department of Biology, Monte L. Bean Museum, and Evolutionary Ecology Laboratories, Brigham Young University , Provo, UT 84602
| | - Byron J Adams
- Department of Biology, Monte L. Bean Museum, and Evolutionary Ecology Laboratories, Brigham Young University , Provo, UT 84602
| | - Gadi V P Reddy
- Department of Research Centers, Western Triangle Agricultural Research Center, Montana State University , 9546 Old Shelby Rd., P.O. Box 656, Conrad, MT 59425 ; USDA-ARS, Southern Insect Management Research Unit, 141 Experiment Station Road, P.O. Box 346, Stoneville, MS 38776
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