QTL discovery for Japanese beetle resistance in aphid-resistant germplasm, stacking aphid-resistant genes, and metabolite profiling studies in soybean

As public institutions and seed companies incorporate soybean aphid (<Aphis glycines> Matsumura) resistance genes into soybean [<Glycine max >(L.) Merr.] cultivars, it is important to retain resistance to insect defoliators. In order to improve MSU aphid-resistant germplasm for resistance to Japanese beetle (<Popillia japonica> Newman), a population was derived from a cross between E06906 (MSU) and another aphid-resistant source, LD05-16060 (Uni. of Illinois) that showed lower susceptibility to Japanese beetle. A QTL (Quantitative Trait Loci) mapping approach with a subset of 94 individuals on 15 chromosomes indicated the presence of five QTL (QTL-M, QTL-G, QTL-H, QTL-D1b and QTL-E) previously reported to confer resistance to several other soybean defoliators, and one published QTL to confer Japanese beetle-resistance. More importantly, three new QTL were found on LG-A1, LG-A2, and LG-C2; they were also detected with 234 individuals. Candidate gene analysis for resistant QTL found key enzymes involved in flavonoid biosynthesis pathway, thus a comprehensive flavonoid profiling study was conducted using High Performance Liquid Chromatography/tandem Mass Spectrometry (HPLC/MS/MS) on three susceptible and three resistant lines. 32 distinct peaks corresponding to glycosides or aglycones of Daidzein, Genistein, Glycetein, Kaempferol, Naringenin, and Quercetin were found in damaged and un-damaged leaflets. Higher abundances of flavonoids were found in damaged leaflets of LD05-16060. It appears that differential susceptibility to Japanese beetle observed between LD05 and E06906, can be explained by differences in feeding-deterrent and phago-stimulant flavonoids. Furthermore, this mapping population gave an opportunity to stack <Rag1> and <rag3> aphid-resistant genes. Pyramiding multiple resistance genes, particularly with different modes of action, has great potential to provide durable resistance. This dissertation also reports MSU soybean breeding program's research on stacking <rag3>, <rag4>, <rag1b>, and <rag1c> aphid- resistant genes from a population of 727 F2 individuals derived from two (Plant Introduction) PI s. Four trials in greenhouse and field were conducted for phenotypic evaluations. SSR and SNP markers linked to these genes were used for the genotypic selections. Repeatedly in all trials <rag3-rag1c> lines outperformed other lines showing great consistency in their resistance. Additionally, <rag3-rag4-rag1c> and <rag3-rag4-rag1b> stacks also provided significantly more resistance than other gene combinations.

Author dc:creator

• Chandrasena, Desmi Indumali

Contributors dc:contributor

• Wang, Dechun
• DiFonzo, Christina
• Kelly, James
• Iezzoni, Amy

• Aphids--Control
• Japanese beetle
• Quantitative genetics
• Soybean--Diseases and pests

Statement dc:rights

• In Copyright

Language dc:language

English

Identifier

etd:1100
isbn:9781267752628
isbn:1267752629
oclc:931883922
umi:3544509
local:Chandrasena_grad.msu_0128D_11631

OAI identifier oai:identifier

oai:d.lib.msu.edu:etd_1100