TITLE:
Association Analysis and Identification of SNP Markers for Stemphylium Leaf Spot (Stemphylium botryosum f. sp. spinacia) Resistance in Spinach (Spinacia oleracea)
AUTHORS:
Ainong Shi, Beiquan Mou, Jim Correll, Steven T. Koike, Dennis Motes, Jun Qin, Yuejin Weng, Wei Yang
KEYWORDS:
Genotyping by Sequencing (GBS), Disease Resistance, Single Nucleotide Polymorphism (SNP), Spinacia oleracea, Stemphylium botryosum, Stemphylium Leaf Spot
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.7 No.12,
August
22,
2016
ABSTRACT: Stemphylium leaf spot, caused by Stemphylium
botryosum f. sp. spinacia, is an important
fungal disease of spinach (Spinacia
oleracea L.). The aim of this study was to conduct association analysis to
identify single nucleotide polymorphism (SNP) markers associated with Stemphylium
leaf spot resistance in spinach. A total of 273 spinach genotypes, including
265 accessions from the USDA spinach germplasm collection and eight commercial
cultivars, were used in this study. Phenotyping for Stemphylium leaf spot
resistance was evaluated in greenhouse; genotyping was conducted using
genotyping by sequencing (GBS) with 787 SNPs; and single marker regression,
general linear model, and mixed linear model were used for association analysis
of Stemphylium leaf spot. Spinach genotypes showed a skewed distribution for
Stemphylium leaf spot resistance, with a range from 0.2% to 23.5% disease
severity, suggesting that Stemphylium leaf spot resistance in spinach is a
complex, quantitative trait. Association analysis indicated that eight SNP
markers, AYZV02052595_115, AYZV02052595_122, AYZV02057770_10404, AYZV02129827_205,
AYZV0-2152692_182, AYZV02180153_337, AYZV02225889_197, and AYZV02258563_213
were strongly associated with Stemphylium leaf spot resistance, with a Log of
the Odds (LOD) of 2.5 or above. The SNP markers may provide a tool to select
for Stemphylium leaf spot resistance in spinach breeding programs through
marker-assisted selection (MAS).