1
|
Chen YJ, Catto MA, Pandey S, Leal-Bertioli S, Abney M, Hunt BG, Bag S, Culbreath A, Srinivasan R. Characterization of gene expression patterns in response to an orthotospovirus infection between two diploid peanut species and their hybrid. FRONTIERS IN PLANT SCIENCE 2023; 14:1270531. [PMID: 38034554 PMCID: PMC10683084 DOI: 10.3389/fpls.2023.1270531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 10/11/2023] [Indexed: 12/02/2023]
Abstract
Tomato spotted wilt orthotospovirus (TSWV) transmitted by thrips causes significant yield loss in peanut (Arachis hypogaea L.) production. Use of peanut cultivars with moderate field resistance has been critical for TSWV management. However, current TSWV resistance is often not adequate, and the availability of sources of tetraploid resistance to TSWV is very limited. Allotetraploids derived by crossing wild diploid species could help introgress alleles that confer TSWV resistance into cultivated peanut. Thrips-mediated TSWV screening identified two diploids and their allotetraploid possessing the AA, BB, and AABB genomes Arachis stenosperma V10309, Arachis valida GK30011, and [A. stenosperma × A. valida]4x (ValSten1), respectively. These genotypes had reduced TSWV infection and accumulation in comparison with peanut of pure cultivated pedigree. Transcriptomes from TSWV-infected and non-infected samples from A. stenosperma, A. valida, and ValSten1 were assembled, and differentially expressed genes (DEGs) following TSWV infection were assessed. There were 3,196, 8,380, and 1,312 significant DEGs in A. stenosperma, A. valida, and ValSten1, respectively. A higher proportion of genes decreased in expression following TSWV infection for A. stenosperma and ValSten1, whereas a higher proportion of genes increased in expression following infection in A. valida. The number of DEGs previously annotated as defense-related in relation to abiotic and biotic stress was highest in A. valida followed by ValSten1 and A. stenosperma. Plant phytohormone and photosynthesis genes also were differentially expressed in greater numbers in A. valida followed by ValSten1 and A. stenosperma, with over half of those exhibiting decreases in expression.
Collapse
Affiliation(s)
- Yi-Ju Chen
- Entomology Department, University of Georgia, Griffin, GA, United States
| | - Michael A. Catto
- Entomology Department, University of Georgia, Griffin, GA, United States
| | - Sudeep Pandey
- Entomology Department, University of Georgia, Griffin, GA, United States
| | - Soraya Leal-Bertioli
- Plant Pathology Department, University of Georgia, Athens, GA, United States
- Institute of Plant Breeding, Genetics and Genomics, University of Georgia, Athens, GA, United States
| | - Mark Abney
- Entomology Department, University of Georgia, Tifton, GA, United States
| | - Brendan G. Hunt
- Entomology Department, University of Georgia, Griffin, GA, United States
| | - Sudeep Bag
- Plant Pathology Department, University of Georgia, Tifton, GA, United States
| | - Albert Culbreath
- Plant Pathology Department, University of Georgia, Tifton, GA, United States
| | | |
Collapse
|
2
|
Sun Z, Zheng Z, Qi F, Wang J, Wang M, Zhao R, Liu H, Xu J, Qin L, Dong W, Huang B, Han S, Zhang X. Development and evaluation of the utility of GenoBaits Peanut 40K for a peanut MAGIC population. MOLECULAR BREEDING : NEW STRATEGIES IN PLANT IMPROVEMENT 2023; 43:72. [PMID: 37786866 PMCID: PMC10542084 DOI: 10.1007/s11032-023-01417-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 09/07/2023] [Indexed: 10/04/2023]
Abstract
Population and genotype data are essential for genetic mapping. The multi-parent advanced generation intercross (MAGIC) population is a permanent mapping population used for precisely mapping quantitative trait loci. Moreover, genotyping-by-target sequencing (GBTS) is a robust high-throughput genotyping technology characterized by its low cost, flexibility, and limited requirements for information management and support. In this study, an 8-way MAGIC population was constructed using eight elite founder lines. In addition, GenoBaits Peanut 40K was developed and utilized for the constructed MAGIC population. A subset (297 lines) of the MAGIC population at the S2 stage was genotyped using GenoBaits Peanut 40K. Furthermore, these lines and the eight parents were analyzed in terms of pod length, width, area, and perimeter. A total of 27 single nucleotide polymorphisms (SNPs) were revealed to be significantly associated with peanut pod size-related traits according to a genome-wide association study. The GenoBaits Peanut 40K provided herein and the constructed MAGIC population will be applicable for future research to identify the key genes responsible for important peanut traits. Supplementary Information The online version contains supplementary material available at 10.1007/s11032-023-01417-w.
Collapse
Affiliation(s)
- Ziqi Sun
- Institute of Crop Molecular Breeding, Henan Academy of Agricultural Sciences/The Shennong Laboratory/State Industrial Innovation Center of Biological Breeding/Key Laboratory of Oil Crops in Huang-Huai-Hai Plains, Ministry of Agriculture/Henan Provincial Key Laboratory for Oil Crops Improvement, Zhengzhou, Henan China
| | - Zheng Zheng
- Institute of Crop Molecular Breeding, Henan Academy of Agricultural Sciences/The Shennong Laboratory/State Industrial Innovation Center of Biological Breeding/Key Laboratory of Oil Crops in Huang-Huai-Hai Plains, Ministry of Agriculture/Henan Provincial Key Laboratory for Oil Crops Improvement, Zhengzhou, Henan China
| | - Feiyan Qi
- Institute of Crop Molecular Breeding, Henan Academy of Agricultural Sciences/The Shennong Laboratory/State Industrial Innovation Center of Biological Breeding/Key Laboratory of Oil Crops in Huang-Huai-Hai Plains, Ministry of Agriculture/Henan Provincial Key Laboratory for Oil Crops Improvement, Zhengzhou, Henan China
| | - Juan Wang
- Institute of Crop Molecular Breeding, Henan Academy of Agricultural Sciences/The Shennong Laboratory/State Industrial Innovation Center of Biological Breeding/Key Laboratory of Oil Crops in Huang-Huai-Hai Plains, Ministry of Agriculture/Henan Provincial Key Laboratory for Oil Crops Improvement, Zhengzhou, Henan China
| | - Mengmeng Wang
- Institute of Crop Molecular Breeding, Henan Academy of Agricultural Sciences/The Shennong Laboratory/State Industrial Innovation Center of Biological Breeding/Key Laboratory of Oil Crops in Huang-Huai-Hai Plains, Ministry of Agriculture/Henan Provincial Key Laboratory for Oil Crops Improvement, Zhengzhou, Henan China
| | - Ruifang Zhao
- Institute of Crop Molecular Breeding, Henan Academy of Agricultural Sciences/The Shennong Laboratory/State Industrial Innovation Center of Biological Breeding/Key Laboratory of Oil Crops in Huang-Huai-Hai Plains, Ministry of Agriculture/Henan Provincial Key Laboratory for Oil Crops Improvement, Zhengzhou, Henan China
| | - Hua Liu
- Institute of Crop Molecular Breeding, Henan Academy of Agricultural Sciences/The Shennong Laboratory/State Industrial Innovation Center of Biological Breeding/Key Laboratory of Oil Crops in Huang-Huai-Hai Plains, Ministry of Agriculture/Henan Provincial Key Laboratory for Oil Crops Improvement, Zhengzhou, Henan China
| | - Jing Xu
- Institute of Crop Molecular Breeding, Henan Academy of Agricultural Sciences/The Shennong Laboratory/State Industrial Innovation Center of Biological Breeding/Key Laboratory of Oil Crops in Huang-Huai-Hai Plains, Ministry of Agriculture/Henan Provincial Key Laboratory for Oil Crops Improvement, Zhengzhou, Henan China
| | - Li Qin
- Institute of Crop Molecular Breeding, Henan Academy of Agricultural Sciences/The Shennong Laboratory/State Industrial Innovation Center of Biological Breeding/Key Laboratory of Oil Crops in Huang-Huai-Hai Plains, Ministry of Agriculture/Henan Provincial Key Laboratory for Oil Crops Improvement, Zhengzhou, Henan China
| | - Wenzhao Dong
- Institute of Crop Molecular Breeding, Henan Academy of Agricultural Sciences/The Shennong Laboratory/State Industrial Innovation Center of Biological Breeding/Key Laboratory of Oil Crops in Huang-Huai-Hai Plains, Ministry of Agriculture/Henan Provincial Key Laboratory for Oil Crops Improvement, Zhengzhou, Henan China
| | - Bingyan Huang
- Institute of Crop Molecular Breeding, Henan Academy of Agricultural Sciences/The Shennong Laboratory/State Industrial Innovation Center of Biological Breeding/Key Laboratory of Oil Crops in Huang-Huai-Hai Plains, Ministry of Agriculture/Henan Provincial Key Laboratory for Oil Crops Improvement, Zhengzhou, Henan China
| | - Suoyi Han
- Institute of Crop Molecular Breeding, Henan Academy of Agricultural Sciences/The Shennong Laboratory/State Industrial Innovation Center of Biological Breeding/Key Laboratory of Oil Crops in Huang-Huai-Hai Plains, Ministry of Agriculture/Henan Provincial Key Laboratory for Oil Crops Improvement, Zhengzhou, Henan China
| | - Xinyou Zhang
- Institute of Crop Molecular Breeding, Henan Academy of Agricultural Sciences/The Shennong Laboratory/State Industrial Innovation Center of Biological Breeding/Key Laboratory of Oil Crops in Huang-Huai-Hai Plains, Ministry of Agriculture/Henan Provincial Key Laboratory for Oil Crops Improvement, Zhengzhou, Henan China
| |
Collapse
|
3
|
Chen YJ, Pandey S, Catto M, Leal-Bertioli S, Abney MR, Bag S, Hopkins M, Culbreath A, Srinivasan R. Evaluation of Wild Peanut Species and Their Allotetraploids for Resistance against Thrips and Thrips-Transmitted Tomato Spotted Wilt Orthotospovirus (TSWV). Pathogens 2023; 12:1102. [PMID: 37764910 PMCID: PMC10536083 DOI: 10.3390/pathogens12091102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 08/23/2023] [Accepted: 08/24/2023] [Indexed: 09/29/2023] Open
Abstract
Thrips-transmitted tomato spotted wilt orthotospovirus (TSWV) causes spotted wilt disease in peanut (Arachis hypogaea L.) and limits yield. Breeding programs have been developing TSWV-resistant cultivars, but availability of sources of resistance against TSWV in cultivated germplasm is extremely limited. Diploid wild Arachis species can serve as important sources of resistance, and despite ploidy barriers (cultivated peanut is tetraploid), their usage in breeding programs is now possible because of the knowledge and development of induced interspecific allotetraploid hybrids. This study screened 10 wild diploid Arachis and six induced allotetraploid genotypes via thrips-mediated TSWV transmission assays and thrips' feeding assays in the greenhouse. Three parameters were evaluated: percent TSWV infection, virus accumulation, and temporal severity of thrips feeding injury. Results indicated that the diploid A. stenosperma accession V10309 and its derivative-induced allotetraploid ValSten1 had the lowest TSWV infection incidences among the evaluated genotypes. Allotetraploid BatDur1 had the lowest thrips-inflicted damage at each week post thrips release, while diploid A. batizocoi accession K9484 and A. duranensis accession V14167 had reduced feeding damage one week post thrips release, and diploids A. valida accession GK30011 and A. batizocoi had reduced feeding damage three weeks post thrips releasethan the others. Overall, plausible TSWV resistance in diploid species and their allotetraploid hybrids was characterized by reduced percent TSWV infection, virus accumulation, and feeding severity. Furthermore, a few diploids and tetraploid hybrids displayed antibiosis against thrips. These results document evidence for resistance against TSWV and thrips in wild diploid Arachis species and peanut-compatible-induced allotetraploids.
Collapse
Affiliation(s)
- Yi-Ju Chen
- Department of Entomology, University of Georgia, Griffin, GA 30223, USA; (Y.-J.C.); (S.P.)
| | - Sudeep Pandey
- Department of Entomology, University of Georgia, Griffin, GA 30223, USA; (Y.-J.C.); (S.P.)
| | - Michael Catto
- Department of Entomology, University of Georgia, Athens, GA 30602, USA;
| | - Soraya Leal-Bertioli
- Department of Plant Pathology, Institute of Plant Breeding, Genetics and Genomics, University of Georgia, Athens, GA 30602, USA;
- Institute of Plant Breeding, Genetics and Genomics, University of Georgia, Athens, GA 30602, USA;
| | - Mark R. Abney
- Department of Entomology, University of Georgia, Tifton, GA 31794, USA;
| | - Sudeep Bag
- Department of Plant Pathology, University of Georgia, Tifton, GA 31793, USA; (S.B.); (A.C.)
| | - Mark Hopkins
- Institute of Plant Breeding, Genetics and Genomics, University of Georgia, Athens, GA 30602, USA;
| | - Albert Culbreath
- Department of Plant Pathology, University of Georgia, Tifton, GA 31793, USA; (S.B.); (A.C.)
| | | |
Collapse
|
4
|
Jeger MJ. Tolerance of plant virus disease: Its genetic, physiological, and epidemiological significance. Food Energy Secur 2022. [DOI: 10.1002/fes3.440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Affiliation(s)
- Michael John Jeger
- Department of Life Sciences, Silwood Park Imperial College London Ascot UK
| |
Collapse
|
5
|
Discrepancies in Serology-Based and Nucleic Acid-Based Detection and Quantitation of Tomato Spotted Wilt Orthotospovirus in Leaf and Root Tissues from Symptomatic and Asymptomatic Peanut Plants. Pathogens 2021; 10:pathogens10111476. [PMID: 34832630 PMCID: PMC8624541 DOI: 10.3390/pathogens10111476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 10/29/2021] [Accepted: 11/10/2021] [Indexed: 11/16/2022] Open
Abstract
Thrips-transmitted tomato spotted wilt orthotospovirus (TSWV) causes spotted wilt disease in peanuts. A serological test (DAS-ELISA) is often used to detect TSWV in peanut leaf samples. However, in a few studies, DAS-ELISA detected more TSWV infection in root than leaf samples. It was not clear if the increased detection was due to increased TSWV accumulation in root tissue or merely an overestimation. Additionally, it was unclear if TSWV detection in asymptomatic plants would be affected by the detection technique. TSWV infection in leaf and root tissue from symptomatic and asymptomatic plants was compared via DAS-ELISA, RT-PCR, and RT-qPCR. TSWV incidence did not vary by DAS-ELISA, RT-PCR, and RT-qPCR in leaf and root samples of symptomatic plants or in leaf samples of asymptomatic plants. In contrast, significantly more TSWV infection and virus load were detected in root samples of asymptomatic plants via DAS-ELISA than other techniques suggesting that DAS-ELISA overestimated TSWV incidence and load. TSWV loads from symptomatic plants via RT-qPCR were higher in leaf than root samples, while TSWV loads in leaf and root samples from asymptomatic plants were not different but were lower than those in symptomatic plants. These findings suggested that peanut tissue type and detection technique could affect accurate TSWV detection and/or quantitation.
Collapse
|
6
|
Impact of Host Resistance to Tomato Spotted Wilt Orthotospovirus in Peanut Cultivars on Virus Population Genetics and Thrips Fitness. Pathogens 2021; 10:pathogens10111418. [PMID: 34832574 PMCID: PMC8625697 DOI: 10.3390/pathogens10111418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 10/28/2021] [Accepted: 10/29/2021] [Indexed: 11/25/2022] Open
Abstract
Thrips-transmitted tomato spotted wilt orthotospovirus (TSWV) is a major constraint to peanut production in the southeastern United States. Peanut cultivars with resistance to TSWV have been widely used for over twenty years. Intensive usage of resistant cultivars has raised concerns about possible selection pressure against TSWV and a likelihood of resistance breakdown. Population genetics of TSWV isolates collected from cultivars with varying levels of TSWV resistance was investigated using five TSWV genes. Phylogenetic trees of genes did not indicate host resistance-based clustering of TSWV isolates. Genetic variation in TSWV isolates and neutrality tests suggested recent population expansion. Mutation and purifying selection seem to be the major forces driving TSWV evolution. Positive selection was found in N and RdRp genes but was not influenced by TSWV resistance. Population differentiation occurred between isolates collected from 1998 and 2010 and from 2016 to 2019 but not between isolates from susceptible and resistant cultivars. Evaluated TSWV-resistant cultivars differed, albeit not substantially, in their susceptibility to thrips. Thrips oviposition was reduced, and development was delayed in some cultivars. Overall, no evidence was found to support exertion of selection pressure on TSWV by host resistance in peanut cultivars, and some cultivars differentially affected thrips fitness than others.
Collapse
|
7
|
Defense-Related Gene Expression Following an Orthotospovirus Infection Is Influenced by Host Resistance in Arachis hypogaea. Viruses 2021; 13:v13071303. [PMID: 34372510 PMCID: PMC8310252 DOI: 10.3390/v13071303] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 07/01/2021] [Accepted: 07/03/2021] [Indexed: 12/13/2022] Open
Abstract
Planting resistant cultivars is the most effective tactic to manage the thrips-transmitted tomato spotted wilt orthotospovirus (TSWV) in peanut plants. However, molecular mechanisms conferring resistance to TSWV in resistant cultivars are unknown. In this study, transcriptomes of TSWV-susceptible (SunOleic 97R) and field-resistant (Tifguard) peanut cultivars with and without TSWV infection were assembled and differentially expressed genes (DEGs) were compared. There were 4605 and 2579 significant DEGs in SunOleic 97R and Tifguard, respectively. Despite the lower number of DEGs in Tifguard, an increased proportion of defense-related genes were upregulated in Tifguard than in the susceptible cultivar. Examples included disease resistance (R) proteins, leucine-rich repeats, stilbene synthase, dicer, and calmodulin. Pathway analysis revealed the increased downregulation of genes associated with defense and photosynthesis in the susceptible cultivar rather than in the resistant cultivar. These results suggest that essential physiological functions were less perturbed in the resistant cultivar than in the susceptible cultivar and that the defense response following TSWV infection was more robust in the resistant cultivar than in the susceptible cultivar.
Collapse
|
8
|
Marchant WG, Legarrea S, Smeda JR, Mutschler MA, Srinivasan R. Evaluating Acylsugars-Mediated Resistance in Tomato against Bemisia tabaci and Transmission of Tomato Yellow Leaf Curl Virus. INSECTS 2020; 11:insects11120842. [PMID: 33260730 PMCID: PMC7760652 DOI: 10.3390/insects11120842] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 11/22/2020] [Accepted: 11/25/2020] [Indexed: 02/02/2023]
Abstract
The sweetpotato whitefly, Bemisia tabaci, is a major pest of cultivated tomato. Whitefly feeding-related injuries and transmission of viruses including tomato yellow leaf curl virus (TYLCV) cause serious losses. Management strategy includes planting resistant cultivars/hybrids. However, TYLCV resistance is incomplete and whiteflies on TYLCV-resistant cultivars/hybrids are managed by insecticides. Acylsugars'-mediated resistance against whiteflies has been introgressed from wild solanums into cultivated tomato. This study evaluated acylsugar-producing tomato lines with quantitative trait loci (QTL) containing introgressions from Solanum pennellii LA716, known to alter acylsugars' levels or chemistry. Evaluated acylsugar-producing lines were the benchmark line CU071026, QTL6/CU071026-a CU071026 sister line with QTL6, and three other CU071026 sister lines with varying QTLs-FA2/CU71026, FA7/CU071026, and FA2/FA7/CU071026. Non-acylsugar tomato hybrid Florida 47 (FL47) was also evaluated. Acylsugars' amounts in FA7/CU071026 and FA2/FA7/CU071026 were 1.4 to 2.2 times greater than in other acylsugar-producing lines. Short chain fatty acid, i-C5, was dominant in all acylsugar-producing lines. Long chain fatty acids, n-C10 and n-C12, were more abundant in FA7/CU071026 and FA2/FA7/CU071026 than in other acylsugar-producing lines. Whiteflies preferentially settled on non-acylsugar hybrid FL47 leaves over three out of five acylsugar-producing lines, and whiteflies settled 5 to 85 times more on abaxial than adaxial leaf surface of FL47 than on acylsugar-producing lines. Whiteflies' survival was 1.5 to 1.9 times lower on acylsugar-producing lines than in FL47. Nevertheless, whiteflies' developmental time was up to 12.5% shorter on acylsugar-producing lines than on FL47. TYLCV infection following whitefly-mediated transmission to acylsugar-producing lines was 1.4 to 2.8 times lower than FL47, and TYLCV acquisition by whiteflies from acylsugar-producing lines was up to 77% lower than from FL47. However, TYLCV accumulation in acylsugar-producing lines following infection and TYLCV loads in whiteflies upon acquisition from acylsugar-producing lines were not different from FL47. Combining TYLCV resistance with acylsugars'-mediated whitefly resistance in cultivated tomato could substantially benefit whiteflies and TYLCV management.
Collapse
Affiliation(s)
- Wendy G. Marchant
- Department of Entomology, University of Georgia, 2360 Rainwater Road, Tifton, GA 31793, USA; (W.G.M.); (S.L.)
| | - Saioa Legarrea
- Department of Entomology, University of Georgia, 2360 Rainwater Road, Tifton, GA 31793, USA; (W.G.M.); (S.L.)
| | - John R. Smeda
- Section of Plant Breeding and Genetics, School of Integrative Plant Science, Cornell University, 257 Emerson Hall, Ithaca, NY 30602, USA; (J.R.S.); (M.A.M.)
| | - Martha A. Mutschler
- Section of Plant Breeding and Genetics, School of Integrative Plant Science, Cornell University, 257 Emerson Hall, Ithaca, NY 30602, USA; (J.R.S.); (M.A.M.)
| | - Rajagopalbabu Srinivasan
- Department of Entomology, University of Georgia, 1109 Experiment Street, Griffin, GA 310223, USA
- Correspondence: ; Tel.: +770-229-3099
| |
Collapse
|
9
|
Chappell TM, Codod CB, Williams BW, Kemerait RC, Culbreath AK, Kennedy GG. Adding Epidemiologically Important Meteorological Data to Peanut Rx, the Risk Assessment Framework for Spotted Wilt of Peanut. PHYTOPATHOLOGY 2020; 110:1199-1207. [PMID: 32133919 DOI: 10.1094/phyto-11-19-0438-r] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Management of disease affecting peanut in the southeastern United States has benefited from extensive field research identifying disease-associated risk factors since the 1990s. An assessment of risk factors associated with tomato spotted wilt (TSW), caused by tomato spotted wilt virus and spread exclusively by thrips, is available to growers through Peanut Rx, a tool developed to inform peanut management decisions. Peanut Rx provides an assessment of relative TSW risk as an index. The assessment provides information about the relative degree to which a field characterized by a specified suite of practices is at risk of crop loss caused by TSW. Loss results when infection occurs, and infection rates are determined, in part, by factors outside a grower's control, primarily the abundance of dispersing, viruliferous thrips. In this study, we incorporated meteorological variables useful for predicting thrips dispersal, increasing the robustness of the Peanut Rx framework in relation to variation in the weather. We used data from field experiments and a large grower survey to estimate the relationships between weather and TSW risk mediated by thrips vectors, and developed an addition to Peanut Rx that proved informative and easy to implement. The expected temporal occurrence of major thrips flights, as a function of heat and precipitation, was translated into the existing risk-point system of Peanut Rx. Results from the grower survey further demonstrated the validity of Peanut Rx for guiding growers' decisions to minimize risk of TSW.
Collapse
Affiliation(s)
- Thomas M Chappell
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77843, U.S.A
| | - Clarence B Codod
- Department of Plant Pathology, College of Agricultural and Environmental Science, University of Georgia, Tifton, GA 31793, U.S.A
| | - Blake W Williams
- Department of Plant Pathology, College of Agricultural and Environmental Science, University of Georgia, Tifton, GA 31793, U.S.A
| | - Robert C Kemerait
- Department of Plant Pathology, College of Agricultural and Environmental Science, University of Georgia, Tifton, GA 31793, U.S.A
| | - Albert K Culbreath
- Department of Plant Pathology, College of Agricultural and Environmental Science, University of Georgia, Tifton, GA 31793, U.S.A
| | - George G Kennedy
- Department of Entomology and Plant Pathology, College of Agriculture and Life Sciences, North Carolina State University, Raleigh, NC 27695-7630, U.S.A
| |
Collapse
|
10
|
Marchant WG, Gautam S, Hutton SF, Srinivasan R. Tomato Yellow Leaf Curl Virus-Resistant and -Susceptible Tomato Genotypes Similarly Impact the Virus Population Genetics. FRONTIERS IN PLANT SCIENCE 2020; 11:599697. [PMID: 33365041 PMCID: PMC7750400 DOI: 10.3389/fpls.2020.599697] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 11/13/2020] [Indexed: 05/14/2023]
Abstract
Tomato yellow leaf curl virus is a species in the genus Begomovirus and family Geminiviridae. Tomato yellow leaf curl virus (TYLCV) infection induces severe symptoms on tomato plants and causes serious yield losses worldwide. TYLCV is persistently transmitted by the sweetpotato whitefly, Bemisia tabaci (Gennadius). Cultivars and hybrids with a single or few genes conferring resistance against TYLCV are often planted to mitigate TYLCV-induced losses. These resistant genotypes (cultivars or hybrids) are not immune to TYLCV. They typically develop systemic infection, display mild symptoms, and produce more marketable tomatoes than susceptible genotypes under TYLCV pressure. In several pathosystems, extensive use of resistant cultivars with single dominant resistance-conferring gene has led to intense selection pressure on the virus, development of highly virulent strains, and resistance breakdown. This study assessed differences in TYLCV genomes isolated from susceptible and resistant genotypes in Florida and Georgia. Phylogenetic analyses indicated that Florida and Georgia isolates were distinct from each other. Population genetics analyses with genomes field-collected from resistant and susceptible genotypes from Florida and/or Georgia provided no evidence of a genetic structure between the resistant and susceptible genotypes. No codons in TYLCV genomes from TYLCV-resistant or susceptible genotypes were under positive selection, suggesting that highly virulent or resistance-breaking TYLCV strains might not be common in tomato farmscapes in Florida and Georgia. With TYLCV-resistant genotypes usage increasing recently and multiple tomato crops being planted during a calendar year, host resistance-induced selection pressure on the virus remains a critical issue. To address the same, a greenhouse selection experiment with one TYLCV-resistant and susceptible genotype was conducted. Each genotype was challenged with TYLCV through whitefly-mediated transmission serially 10 times (T1-T10). Population genetics parameters at the genome level were assessed at T1, T5, and T10. Results indicated that genomes from resistant and susceptible genotypes did not differentiate with increasing transmission number, no specific mutations were repeatedly observed, and no positive selection was detected. These results reiterate that resistance in tomato might not be exerting selection pressure against TYLCV to facilitate development of resistance-breaking strains. TYLCV populations rather seem to be shaped by purifying selection and/or population expansion.
Collapse
Affiliation(s)
- Wendy G. Marchant
- Department of Entomology, University of Georgia, Tifton, GA, United States
| | - Saurabh Gautam
- Department of Entomology, University of Georgia, Griffin, GA, United States
| | - Samuel F. Hutton
- Horticulture Sciences Department, University of Florida, Wimauma, FL, United States
| | - Rajagopalbabu Srinivasan
- Department of Entomology, University of Georgia, Griffin, GA, United States
- *Correspondence: Rajagopalbabu Srinivasan
| |
Collapse
|
11
|
Srinivasan R, Abney MR, Lai PC, Culbreath AK, Tallury S, Leal-Bertioli SCM. Resistance to Thrips in Peanut and Implications for Management of Thrips and Thrips-Transmitted Orthotospoviruses in Peanut. FRONTIERS IN PLANT SCIENCE 2018; 9:1604. [PMID: 30459792 PMCID: PMC6232880 DOI: 10.3389/fpls.2018.01604] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 10/17/2018] [Indexed: 05/31/2023]
Abstract
Thrips are major pests of peanut (Arachis hypogaea L.) worldwide, and they serve as vectors of devastating orthotospoviruses such as Tomato spotted wilt virus (TSWV) and Groundnut bud necrosis virus (GBNV). A tremendous effort has been devoted to developing peanut cultivars with resistance to orthotospoviruses. Consequently, cultivars with moderate field resistance to viruses exist, but not much is known about host resistance to thrips. Integrating host plant resistance to thrips in peanut could suppress thrips feeding damage and reduce virus transmission, will decrease insecticide usage, and enhance sustainability in the production system. This review focuses on details of thrips resistance in peanut and identifies future directions for incorporating thrips resistance in peanut cultivars. Research on thrips-host interactions in peanut is predominantly limited to field evaluations of feeding damage, though, laboratory studies have revealed that peanut cultivars could differentially affect thrips feeding and thrips biology. Many runner type cultivars, field resistant to TSWV, representing diverse pedigrees evaluated against thrips in the greenhouse revealed that thrips preferred some cultivars over others, suggesting that antixenosis "non-preference" could contribute to thrips resistance in peanut. In other crops, morphological traits such as leaf architecture and waxiness and spectral reflectance have been associated with thrips non-preference. It is not clear if foliar morphological traits in peanut are associated with reduced preference or non-preference of thrips and need to be evaluated. Besides thrips non-preference, thrips larval survival to adulthood and median developmental time were negatively affected in some peanut cultivars and in a diploid peanut species Arachis diogoi (Hoehne) and its hybrids with a Virginia type cultivar, indicating that antibiosis (negative effects on biology) could also be a factor influencing thrips resistance in peanut. Available field resistance to orthotospoviruses in peanut is not complete, and cultivars can suffer substantial yield loss under high thrips and virus pressure. Integrating thrips resistance with available virus resistance would be ideal to limit losses. A discussion of modern technologies such as transgenic resistance, marker assisted selection and RNA interference, and future directions that could be undertaken to integrate resistance to thrips and to orthotospoviruses in peanut cultivars is included in this article.
Collapse
Affiliation(s)
| | - Mark R. Abney
- Department of Entomology, University of Georgia, Tifton, GA, United States
| | - Pin-Chu Lai
- Department of Entomology, University of Georgia, Griffin, GA, United States
| | - Albert K. Culbreath
- Department of Plant Pathology, University of Georgia, Tifton, GA, United States
| | - Shyam Tallury
- United States Department of Agriculture – Agricultural Research Service, Griffin, GA, United States
| | | |
Collapse
|
12
|
Marasigan K, Toews M, Kemerait R, Abney MR, Culbreath A, Srinivasan R. Evaluation of Alternatives to an Organophosphate Insecticide with Selected Cultural Practices: Effects on Thrips, Frankliniella fusca, and Incidence of Spotted Wilt in Peanut Farmscapes. JOURNAL OF ECONOMIC ENTOMOLOGY 2018; 111:1030-1041. [PMID: 29635299 DOI: 10.1093/jee/toy079] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Indexed: 06/08/2023]
Abstract
Peanut growers use a combination of tactics to manage spotted wilt disease caused by thrips-transmitted Tomato spotted wilt virus (TSWV). They include planting TSWV-resistant cultivars, application of insecticides, and various cultural practices. Two commonly used insecticides against thrips are aldicarb and phorate. Both insecticides exhibit broad-spectrum toxicity. Recent research has led to the identification of potential alternatives to aldicarb and phorate. In this study, along with reduced-risk, alternative insecticides, we evaluated the effect of conventional versus strip tillage; single versus twin row seeding pattern; and 13 seed/m versus 20 seed/m on thips density, feeding injury, and spotted wilt incidence. Three field trials were conducted in Georgia in 2012 and 2013. Thrips counts, thrips feeding injuriy, and incidence of spotted wilt were less under strip tillage than under conventional tillage. Reduced feeding injury from thrips was observed on twin-row plots compared with single-row plots. Thrips counts, thrips feeding injury, and incidence of spotted wilt did not vary by seeding rate. Yield from twin-row plots was greater than yield from single-row plots only in 2012. Yield was not affected by other cultural practices. Alternative insecticides, including imidacloprid and spinetoram, were as effective as phorate in suppressing thrips and reducing incidence of spotted wilt in conjunction with cultural practices. Results suggest that cultural practices and reduced-risk insecticides (alternatives to aldicarb and phorate) can effectively suppress thrips and incidence of spotted wilt in peanut.
Collapse
Affiliation(s)
- K Marasigan
- Department of Entomology, University of Georgia, Tifton, GA
| | - M Toews
- Department of Entomology, University of Georgia, Tifton, GA
| | - R Kemerait
- Department of Plant Pathology, University of Georgia, Tifton, GA
| | - M R Abney
- Department of Entomology, University of Georgia, Tifton, GA
| | - A Culbreath
- Department of Plant Pathology, University of Georgia, Tifton, GA
| | - R Srinivasan
- Department of Entomology, University of Georgia, Tifton, GA
| |
Collapse
|
13
|
Zhao Z, Tseng YC, Peng Z, Lopez Y, Chen CY, Tillman BL, Dang P, Wang J. Refining a major QTL controlling spotted wilt disease resistance in cultivated peanut (Arachis hypogaea L.) and evaluating its contribution to the resistance variations in peanut germplasm. BMC Genet 2018; 19:17. [PMID: 29571286 PMCID: PMC5865372 DOI: 10.1186/s12863-018-0601-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Accepted: 03/09/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Spotted wilt, caused by tomato spotted wilt virus (TSWV), has been one of major diseases in cultivated peanut grown in the southeastern United States (US) since 1990. Previously a major quantitative trait locus (QTL) controlling spotted wilt disease resistance was mapped to an interval of 2.55 cM genetic distance corresponding to a physical distance of 14.4 Mb on chromosome A01 of peanut by using a segregating F2 population. The current study focuses on refining this major QTL region and evaluating its contributions in the US peanut mini-core germplasm. RESULTS Two simple sequence repeat (SSR) markers associated with the major QTL were used to genotype F5 individuals, and 25 heterozygous individuals were selected and developed into an F6 segregating population. Based on visual evaluation in the field, a total of 194 susceptible F6 individuals were selected and planted into F7 generation for phenotyping. Nine SSR markers were used to genotype the 194 F6 individuals, and QTL analysis revealed that a confidence interval of 15.2 Mb region had the QTL with 22.8% phenotypic variation explained (PVE). This QTL interval was further genotyped using the Amplicon-seq method. A total of 81 non-redundant single nucleotide polymorphism (SNP) and eight InDel markers were detected. No recombinant was detected among the F6 individuals. Two InDel markers were integrated into the linkage group and helped to refine the confidence interval of this QTL into a 0.8 Mb region. To test the QTL contributes to the resistance variance in US peanut mini-core germplasm, two flanking SSR markers were used to genotype 107 mini-core germplasm accessions. No statistically significant association was observed between the genotype at the QTL region and spotted wilt resistance in the mini-core germplasm, which indicated that the resistance allelic region at this QTL didn't contribute to the resistance variance in the US peanut mini-core germplasm, thus was a unique resistance source. CONCLUSION A major QTL related to spotted wilt disease resistance in peanut was refined to a 0.8 Mb region on A01 chromosome, which didn't relate to spotted wilt disease resistance in the US peanut mini-core germplasm and might be a unique genetic source.
Collapse
Affiliation(s)
- Zifan Zhao
- Agronomy Department, University of Florida, Gainesville, FL, 32610, USA
| | - Yu-Chien Tseng
- Agronomy Department, University of Florida, Gainesville, FL, 32610, USA.,North Florida Research and Education Center, University of Florida, Marianna, FL, 32446, USA
| | - Ze Peng
- Agronomy Department, University of Florida, Gainesville, FL, 32610, USA
| | - Yolanda Lopez
- Agronomy Department, University of Florida, Gainesville, FL, 32610, USA
| | - Charles Y Chen
- Department of Crop, Soil and Environmental Sciences, Auburn University, Auburn, AL, 36849, USA
| | - Barry L Tillman
- Agronomy Department, University of Florida, Gainesville, FL, 32610, USA.,North Florida Research and Education Center, University of Florida, Marianna, FL, 32446, USA
| | - Phat Dang
- USDA-ARS National Peanut Research Laboratory, Dawson, GA, 39842, USA
| | - Jianping Wang
- Agronomy Department, University of Florida, Gainesville, FL, 32610, USA. .,Center for Genomics and Biotechnology, Key Laboratory of Genetics, Breeding and Multiple Utilization of Crops, Ministry of Education; Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China.
| |
Collapse
|
14
|
Shrestha A, Champagne DE, Culbreath AK, Rotenberg D, Whitfield AE, Srinivasan R. Transcriptome changes associated with Tomato spotted wilt virus infection in various life stages of its thrips vector, Frankliniella fusca (Hinds). J Gen Virol 2017; 98:2156-2170. [DOI: 10.1099/jgv.0.000874] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Affiliation(s)
- Anita Shrestha
- Department of Entomology, University of Georgia, Tifton, GA 31793, USA
| | | | | | - Dorith Rotenberg
- Department of Plant Pathology, Kansas State University, Manhattan, KS 66506, USA
| | - Anna E. Whitfield
- Department of Plant Pathology, Kansas State University, Manhattan, KS 66506, USA
| | | |
Collapse
|
15
|
Srinivasan R, Abney MR, Culbreath AK, Kemerait RC, Tubbs RS, Monfort WS, Pappu HR. Three decades of managing Tomato spotted wilt virus in peanut in southeastern United States. Virus Res 2017; 241:203-212. [PMID: 28549856 DOI: 10.1016/j.virusres.2017.05.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 05/19/2017] [Accepted: 05/21/2017] [Indexed: 11/30/2022]
Abstract
Southeastern states namely Georgia, Florida, and Alabama produce two-thirds of the peanuts in the United States. Thrips-transmitted Tomato spotted wilt virus (TSWV), which causes spotted wilt disease, has been a major impediment to peanut production for the past three decades. The cultivars grown in the 1980s were extremely susceptible to TSWV. Early yield losses extended to tens of millions of dollars each year (up to 100% loss in many fields). This situation led to the creation of an interdisciplinary team known as "SWAT: Spotted Wilt Action Team". Initial efforts focused on risk mitigation using a combination of chemical and cultural management practices along with a strong investment in breeding programs. Beginning in the mid 1990s, cultivars with field resistance were developed and integrated with cultural and chemical management options. A Risk Mitigation Index (Peanut Rx) was made available to growers to assess risks, and provide options for mitigating risks such as planting field resistant cultivars with in-furrow insecticides, planting after peak thrips incidence, planting in twin rows, and increasing seeding rates. These efforts helped curtail losses due to spotted wilt. The Peanut Rx continues to be refined every year based on new research findings. Breeding efforts, predominantly in Georgia and Florida, continue to develop cultivars with incremental field resistance. The present-day cultivars (third-generation TSWV-resistant cultivars released after 2010) possess substantially greater field resistance than second-generation (cultivars released from 2000 to 2010) and first-generation (cultivars released from 1994 to 2000) TSWV resistant cultivars. Despite increased field resistance, these cultivars are not immune to TSWV and succumb under high thrips and TSWV pressure. Therefore, field resistant cultivars cannot serve as a 'stand-alone' option and have to be integrated with other management options. The mechanism of resistance is also unknown in field resistant cultivars. Recent research in our laboratory evaluated field resistant cultivars against thrips and TSWV. Results revealed that some resistant cultivars suppressed thrips feeding and development, and they accumulated fewer viral copies than susceptible cultivars. Transcriptomes developed with the aid of Next Generation Sequencing revealed differential gene expression patterns following TSWV infection in susceptible than field resistant cultivars. Results revealed that the upregulation of transcripts pertaining to constitutive and induced plant defense proteins in TSWV resistant cultivars was more robust over susceptible cultivars. On the flipside, the long-term effects of using such resistant cultivars on TSWV were assessed by virus population genetics studies. Initial results suggest lack of positive selection pressure on TSWV, and that the sustainable use of resistant cultivars is not threatened. Follow up research is being conducted. Improvements in TSWV management have enhanced sustainability and contributed to increased yields from <2800kg/ha before 1995 to ∼5000kg/ha in 2015.
Collapse
Affiliation(s)
- R Srinivasan
- University of Georgia, 2360 Rainwater Road, Tifton, GA 31793, USA.
| | - M R Abney
- University of Georgia, 2360 Rainwater Road, Tifton, GA 31793, USA
| | - A K Culbreath
- University of Georgia, 2360 Rainwater Road, Tifton, GA 31793, USA
| | - R C Kemerait
- University of Georgia, 2360 Rainwater Road, Tifton, GA 31793, USA
| | - R S Tubbs
- University of Georgia, 2360 Rainwater Road, Tifton, GA 31793, USA
| | - W S Monfort
- University of Georgia, 2360 Rainwater Road, Tifton, GA 31793, USA
| | - H R Pappu
- Washington State University, 345 Johnson hall, Pullman, WA 99164, USA
| |
Collapse
|
16
|
Marasigan K, Toews M, Kemerait R, Abney MR, Culbreath A, Srinivasan R. Evaluation of Alternatives to Carbamate and Organophosphate Insecticides Against Thrips and Tomato Spotted Wilt Virus in Peanut Production. JOURNAL OF ECONOMIC ENTOMOLOGY 2016; 109:544-57. [PMID: 26637534 DOI: 10.1093/jee/tov336] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Thrips are important pests of peanut. They cause severe feeding injuries on peanut foliage in the early season. They also transmit Tomato spotted wilt virus (TSWV), which causes spotted wilt disease. At-plant insecticides and cultivars that exhibit field resistance to TSWV are often used to manage thrips and spotted wilt disease. Historically, peanut growers used the broad-spectrum insecticides aldicarb (IRAC class 1A; Temik) and phorate (IRAC class 1B; Thimet) for managing thrips and thereby reducing TSWV transmission. Aldicarb has not been produced since 2011 and its usage in peanut will be legally phased out in 2018; therefore, identification of alternative chemistries is critical for thrips and spotted wilt management. Here, eight alternative insecticides, with known thrips activity, were evaluated in field trials conducted from 2011 through 2013. In addition, different application methods of alternatives were also evaluated. Imidacloprid (Admire Pro), thiamethoxam (Actara), spinetoram (Radiant), and cyantraniliprole (Exirel) were as effective as aldicarb and phorate in suppressing thrips, but none of the insecticides significantly suppressed spotted wilt incidence. Nevertheless, greenhouse assays demonstrated that the same alternative insecticides were effective in suppressing thrips feeding and reducing TSWV transmission. Spotted wilt incidence in the greenhouse was more severe (∼80%) than in the field (5–25%). In general, field resistance to TSWV in cultivars only marginally influenced spotted wilt incidence. Results suggest that effective management of thrips using alternative insecticides and subsequent feeding reduction could improve yields under low to moderate virus pressure.
Collapse
|
17
|
Shrestha A, Sundaraj S, Culbreath AK, Riley DG, Abney MR, Srinivasan R. Effects of Thrips Density, Mode of Inoculation, and Plant Age on Tomato Spotted Wilt Virus Transmission in Peanut Plants. ENVIRONMENTAL ENTOMOLOGY 2015; 44:136-143. [PMID: 26308816 DOI: 10.1093/ee/nvu013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 11/14/2014] [Indexed: 06/04/2023]
Abstract
Spotted wilt caused by tomato spotted wilt virus (TSWV; family Bunyaviridae; genus Tospovirus) is a serious disease of peanut (Arachis hypogaea L.) in the southeastern United States. Peanut genotypes with field resistance to TSWV are effective in suppressing spotted wilt. All commercially available genotypes with field resistance to TSWV were developed through conventional breeding. As a part of the breeding process, peanut genotypes are regularly screened under field situations. Despite numerous advantages associated with field screening, it is often limited by inconsistent vector (thrips) and TSWV pressure. A greenhouse transmission protocol would aid in thorough screening of selected genotypes and conserve time. In this study, various parameters associated with TSWV transmission, including tobacco thrips, Frankliniella fusca (Hinds) density, mode of inoculation, and plant age, were evaluated. Greater incidences of TSWV infection were obtained with thrips-mediated inoculation when compared with mechanical inoculation. TSWV inoculation with three, five, and 10 thrips resulted in greater incidences of TSWV infection in plants than inoculation with one thrips. However, incidences of TSWV infection did not vary between plants inoculated with three, five, and 10 viruliferous thrips. With both thrips-mediated and mechanical inoculation methods, incidences of TSWV infection in 1-wk-old plants were greater than in 4-wk-old plants. TSWV copy numbers, as determined by qPCR, also decreased with plant age. Results suggest that using at least three thrips per plant and 1- to 2-wk-old plants would maximize TSWV infection in inoculated plants.
Collapse
Affiliation(s)
- Anita Shrestha
- Department of Entomology, University of Georgia, Tifton, GA 31793
| | | | | | - David G Riley
- Department of Entomology, University of Georgia, Tifton, GA 31793
| | - Mark R Abney
- Department of Entomology, University of Georgia, Tifton, GA 31793
| | | |
Collapse
|
18
|
Srinivasan R, Riley D, Diffie S, Shrestha A, Culbreath A. Winter weeds as inoculum sources of tomato spotted wilt virus and as reservoirs for its vector, Frankliniella fusca (Thysanoptera: Thripidae) in farmscapes of Georgia. ENVIRONMENTAL ENTOMOLOGY 2014; 43:410-420. [PMID: 24612539 DOI: 10.1603/en13288] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Thrips-transmitted Tomato spotted wilt virus (TSWV) has a broad host range including crops and weeds. In Georgia, TSWV is known to consistently affect peanut, tomato, pepper, and tobacco production. These crops are grown from March through November. In the crop-free period, weeds are presumed to serve as a green bridge for thrips and TSWV. Previous studies have identified several winter weeds as TSWV and thrips hosts. However, their ability to influence TSWV transmission in crops is still not completely understood. To further understand these interactions, population dynamics of two prevalent vectors, viz., Frankliniella fusca (Hinds) and Frankliniella occidentalis (Pergande), on selected winter weeds were monitored from October through April in four counties from 2004 to 2008. Peak populations were typically recorded in March. F. fusca and F. occidentalis adults were found on winter weeds and their percentages ranged from 0 to 68% in comparison with other adults. Immatures outnumbered all adults. Microcosm experiments indicated that the selected winter weeds differentially supported F. fusca reproduction and development. The time required to complete one generation (adult to adult) ranged from 11 to 16 d. Adult recovery ranged from 0.97 to 2.2 per female released. In addition, transmission assays revealed that thrips efficiently transmitted TSWV from peanut to weeds, the incidence of infection ranged from 10 to 55%. Back transmission assays with thrips from TSWV-infected weeds resulted in up to 75% TSWV infection in peanut. These whole-plant transmission and back transmission assays provide the basis for TSWV persistence in farmscapes year round.
Collapse
Affiliation(s)
- Rajagopalbabu Srinivasan
- Department of Entomology, College of Agriculture and Environmental Sciences, 2360 Rainwater Rd., Tifton, GA 31793, USA
| | | | | | | | | |
Collapse
|
19
|
Sundaraj S, Srinivasan R, Culbreath AK, Riley DG, Pappu HR. Host plant resistance against tomato spotted wilt virus in peanut (Arachis hypogaea) and its impact on susceptibility to the virus, virus population genetics, and vector feeding behavior and survival. PHYTOPATHOLOGY 2014; 104:202-210. [PMID: 24025049 DOI: 10.1094/phyto-04-13-0107-r] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Tomato spotted wilt virus (TSWV) severely affects peanut production in the southeastern United States. Breeding efforts over the last three decades resulted in the release of numerous peanut genotypes with field resistance to TSWV. The degree of field resistance in these genotypes has steadily increased over time, with recently released genotypes exhibiting a higher degree of field resistance than older genotypes. However, most new genotypes have never been evaluated in the greenhouse or laboratory against TSWV or thrips, and the mechanism of resistance is unknown. In this study, TSWV-resistant and -susceptible genotypes were subjected to TSWV mechanical inoculation. The incidence of TSWV infection was 71.7 to 87.2%. Estimation of TSWV nucleocapsid (N) gene copies did not reveal significant differences between resistant and susceptible genotypes. Parsimony and principal component analyses of N gene nucleotide sequences revealed inconsistent differences between virus isolates collected from resistant and susceptible genotypes and between old (collected in 1998) and new (2010) isolates. Amino acid sequence analyses indicated consistent differences between old and new isolates. In addition, we found evidence for overabundance of nonsynonymous substitutions. However, there was no evidence for positive selection. Purifying selection, population expansion, and differentiation seem to have influenced the TSWV populations temporally rather than positive selection induced by host resistance. Choice and no-choice tests indicated that resistant and susceptible genotypes differentially affected thrips feeding and survival. Thrips feeding and survival were suppressed on some resistant genotypes compared with susceptible genotypes. These findings reveal how TSWV resistance in peanut could influence evolution, epidemiology, and management of TSWV.
Collapse
|