Dissertation
CHARACTERIZATION OF VIRUSES IN COUNTRY BEAN AND IDENTIFICATION OF GENETIC RESISTANCE TO APHIDS IN PEA GERMPLASM
Washington State University
Doctor of Philosophy (PhD), Washington State University
01/2021
DOI:
https://doi.org/10.7273/000005473
Handle:
https://hdl.handle.net/2376/119278
Abstract
CHARACTERIZATION OF VIRUSES IN COUNTRY BEAN AND IDENTIFICATION OF GENETIC RESISTANCE TO APHIDS IN PEA GERMPLASM
Abstractby Mohammad Mahfuzur Rahman, Ph.D.
Washington State University
May 2021
Co-Chair: Naidu A. RayapatiCo-Chair: Lyndon Porter
Among the several biotic stress factors, viral diseases are a major constraint to sustainable cultivation of country bean (Lablab purpureus [L.] Sweet, family Fabaceae) in subsistence agriculture in Bangladesh. This study was undertaken to characterize Bean common mosaic necrosis virus (BCMNV) and Dolichos yellow mosaic virus (DoYMV) in country bean samples collected from farmers’ fields. Total nucleic acid preparations from symptomatic leaves were subjected to high-throughput Illumina sequencing followed by Sanger sequencing of viral amplicons to generate near full-length genome sequences of BCMNV and complete sequence of DNA-A and DNA-B components of DoYMV. In pairwise comparisons and phylogenetic analysis of polyprotein sequences, BCMNV isolates from Bangladesh were found to be distinct strains compared to virus isolates from other countries. Grow-out tests showed seed-to-seedling transmission of BCMNV, implying seed-borne nature of the virus in country beans. An analysis of green pods indicated detrimental effects of virus infection on nutritional quality of pods. Phylogenetic analysis and pairwise sequence comparisons of DoYMV sequences from Bangladesh showed close relationship with corresponding viral sequences from India. Some of the DoYMV isolates from Bangladesh were found to be putative recombinants. Studies were conducted to identify sources of resistance to the pea aphid (PA, Acyrthosiphon pisum) using a world-wide collection of 301 pea genotypes available at the USDA facility in Pullman, WA. A cluster analysis associated with the mean number of adults, nymphs and total aphids that developed on pea lines 10 days after releasing a single adult aphid per plant identified six clusters associated with aphid resistance. Genotyping by sequencing based on single-nucleotide polymorphisms (SNPs) were used in genome-wide association mapping to locate genes or quantitative trait loci linked to PA resistance in which three, nine and six SNPs were associated with resistance to adult, nymph and total number of PA that developed on pea lines, respectively. Seventeen candidate genes were identified in response to PA resistance in pea. The sources of resistance can effectively be used in pea breeding programs to develop cultivars with improved resistance against the pea aphid, a major pest and a vector of viruses damaging peas.
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Details
- Title
- CHARACTERIZATION OF VIRUSES IN COUNTRY BEAN AND IDENTIFICATION OF GENETIC RESISTANCE TO APHIDS IN PEA GERMPLASM
- Creators
- Mohammad Rahman
- Contributors
- Naidu Rayapati (Advisor)Naidu Rayapati (Committee Member)Lyndon Porter (Advisor)Lyndon Porter (Committee Member)Gary Grove (Committee Member)Achour Amiri (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Department of Plant Pathology
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Publisher
- Washington State University
- Number of pages
- 191
- Identifiers
- 99900592056101842
- Language
- English
- Resource Type
- Dissertation