Skip to Main Content
Frequently Asked Questions
Submit an ETD
Global Search Box
Need Help?
Keyword Search
Participating Institutions
Advanced Search
School Logo
Files
File List
Dissertation_Gedling_2018_final.pdf (12.57 MB)
ETD Abstract Container
Abstract Header
Mechanisms of Resistance and Candidate Gene Analysis towards
Fusarium graminearum
and
Phytophthora sojae
in Soybean
Author Info
Gedling, Cassidy Renee
Permalink:
http://rave.ohiolink.edu/etdc/view?acc_num=osu1524160566193078
Abstract Details
Year and Degree
2018, Doctor of Philosophy, Ohio State University, Plant Pathology.
Abstract
Numerous diseases affect soybean [
Glycine max
(L.) Merr] yields throughout the growing season in Ohio. Two soil borne pathogens
Fusarium graminearum
and
Phytophthora sojae
are known to reduce stand and yield. Currently, fungicide seed treatments are used to manage these pathogens, however, host plant resistance is often the best management strategy for field crops. Thus, the overall objective of the five chapters this dissertation was to identify mechanisms and candidate genes of resistance that are effective towards seed, seedling, and root rots caused by
Fusarium graminearum
and
P. sojae
in soybean. Quantitative disease resistance loci (QDRL) have been mapped in two separate recombinant inbred line (RIL) populations for resistance to
Fusarium graminearum
. In the F
7:8
RIL derived from a cross Magellan X PI 567516C, one major QDRL was mapped. Fine mapping of this region identified four putative candidate genes for resistance to
Fusarium graminearum
. In an additional population of Wyandot x PI 567301B, a major and minor QDRL was mapped to chromosome 8 and 6, respectively. Hybrid genome assembly, fine mapping, and RNA sequencing analysis narrowed the major QDRL to 2.5 cM containing three putative candidate genes for resistance or susceptibility. To validate these candidate genes functional analysis needs to be assessed at the seed level. To achieve this we modified the Apple latent spherical virus (ASLV) which allowed for direct inoculation of VIGS-triggering ALSV agro-infiltrated Nicotiana benthamiana leaves onto soybean unifoliates. However, this method is genotype dependent; the virus is detected in numerous reproductive structures including pods, embryos, stems, leaves, and roots. The last objective of this dissertation focuses on mechanisms of partial resistance to
Phytophthora sojae
. This oomycete is a leading pathogen of soybean, causing root and stem rot (PRR) across the North Central Region in the U.S. Twenty phenotypic quantitative trait loci (pQTL) were previously mapped in a F
9:11
Conrad x Sloan recombinant inbred line (RIL) population on chromosomes 1, 4, 9, 15, 16, 18, and 19; however, these regions encompass large portions of the genome. Thus a systems genetics approach that incorporates expression QTL (eQTL) mapping, functional genomics, and gene co-expression analysis was taken to identify molecular mechanisms contributing towards partial resistance, with the specific objective of reducing the list of candidate genes potentially underpinning pQTL. A greater number of eQTL were mapped in inoculated samples relative to mock, indicating transcriptional reprogramming due to
P. sojae
infection. Of the six co-expression modules identified, three were related to PRR susceptibility driven by three casual hotspots. GO enrichment of casual hotspot GM_17_D indicates that cell wall modification is a putative mechanism for
P. sojae
resistance. A total of four eQTL and one eQTL hotspots were found to be co-localized with pQTL and identified five candidate genes for resistance.
Committee
Anne Dorrance, Dr. (Advisor)
Leah McHale, Dr. (Committee Member)
Christopher Taylor, Dr. (Committee Member)
Feng Qu, Dr. (Committee Member)
Pages
465 p.
Subject Headings
Genetics
;
Plant Biology
;
Plant Pathology
;
Plant Sciences
Keywords
eQTL
;
QTL
;
WGCNA
;
hybrid genome assembly
;
VIGS
;
ALSV
;
QDRL
;
partial resistance
;
quantitative resistance
;
systems genetics
Recommended Citations
Refworks
EndNote
RIS
Mendeley
Citations
Gedling, C. R. (2018).
Mechanisms of Resistance and Candidate Gene Analysis towards
Fusarium graminearum
and
Phytophthora sojae
in Soybean
[Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1524160566193078
APA Style (7th edition)
Gedling, Cassidy.
Mechanisms of Resistance and Candidate Gene Analysis towards
Fusarium graminearum
and
Phytophthora sojae
in Soybean .
2018. Ohio State University, Doctoral dissertation.
OhioLINK Electronic Theses and Dissertations Center
, http://rave.ohiolink.edu/etdc/view?acc_num=osu1524160566193078.
MLA Style (8th edition)
Gedling, Cassidy. "Mechanisms of Resistance and Candidate Gene Analysis towards
Fusarium graminearum
and
Phytophthora sojae
in Soybean ." Doctoral dissertation, Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1524160566193078
Chicago Manual of Style (17th edition)
Abstract Footer
Document number:
osu1524160566193078
Download Count:
5,756
Copyright Info
© 2018, some rights reserved.
Mechanisms of Resistance and Candidate Gene Analysis towards
Fusarium graminearum
and
Phytophthora sojae
in Soybean by Cassidy Renee Gedling is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License. Based on a work at etd.ohiolink.edu.
This open access ETD is published by The Ohio State University and OhioLINK.