QTL mapping and candidate genes for resistance to Fusarium ear rot and fumonisin contamination in maize

Abstract

Background Fusarium verticillioides is a common maize pathogen causing ear rot (FER) and contamination of the grains with the fumonisin B1 (FB1) mycotoxin. Resistance to FER and FB1 contamination are quantitative traits, affected by environmental conditions, and completely resistant maize genotypes to the pathogen are so far unknown. In order to uncover genomic regions associated to reduced FER and FB1 contamination and identify molecular markers for assisted selection, an F2:3 population of 188 progenies was developed crossing CO441 (resistant) and CO354 (susceptible) genotypes. FER severity and FB1 contamination content were evaluated over 2 years and sowing dates (early and late) in ears artificially inoculated with F. verticillioides by the use of either side-needle or toothpick inoculation techniques.ResultsWeather conditions significantly changed in the two phenotyping seasons and FER and FB1 content distribution significantly differed in the F3 progenies according to the year and the sowing time. Significant positive correlations (P < 0.01) were detected between FER and FB1 contamination, ranging from 0.72 to 0.81. A low positive correlation was determined between FB1 contamination and silking time (DTS). A genetic map was generated for the cross, based on 41 microsatellite markers and 342 single nucleotide polymorphisms (SNPs) derived from Genotyping-by-Sequencing (GBS). QTL analyses revealed 15 QTLs for FER, 17 QTLs for FB1 contamination and nine QTLs for DTS. Eight QTLs located on linkage group (LG) 1, 2, 3, 6, 7 and 9 were in common between FER and FB1, making possible the selection of genotypes with both low disease severity and low fumonisin contamination. Moreover, five QTLs on LGs 1, 2, 4, 5 and 9 located close to previously reported QTLs for resistance to other mycotoxigenic fungi. Finally, 24 candidate genes for resistance to F. verticillioides are proposed combining previous transcriptomic data with QTL mapping.ConclusionsThis study identified a set of QTLs and candidate genes that could accelerate breeding for resistance of maize lines showing reduced disease severity and low mycotoxin contamination determined by F. verticillioides.Electronic supplementary materialThe online version of this article (doi:10.1186/s12870-017-0970-1) contains supplementary material, which is available to authorized users.

High‐density linkage map reveals QTL underlying growth traits in AP13×VS16 biparental population of switchgrass

“…Increase of number of markers and population size and integration of data from multiple environments overcomes some of these limitations ((Robertson, Payne, & Holland, ). QTL and associated candidate genes for corn Fusarium air rot disease were identified after integration of GBS SNPs in linkage maps (Maschietto et al, ). Several linkage maps were reported in switchgrass using RFLP (Missaoui, ); SRDF (Missaoui et al, ); SSR (Liu, Wu, Wang, & Samuels, ; Okada et al, ; Serbaet al, ; Wang, Samuels, & Wu, ); STS (Okada et al, ; Serba et al, ); DArT (Serba et al, ); and SNP (Lu et al, ) markers.…”

“…Thus, the linkage map generated in this study, which was aligned with the published switchgrass genome, shows great importance for future endeavor in QTL mapping and application of MAS. Currently, a small obstacle in using such map for QTL mapping is the limitation of marker numbers in chromosomes (Maschietto et al, ; Serbaet al, ). Thus, reduction of marker number in each chromosome was done systematically, taking uniform marker distribution into account, for this QTL mapping using QTL cartographer.…”

Analysis of Fusarium ear rot and fumonisin contamination in testcrosses of a maize biparental population

“…As agronomic control methods of fumonisin contamination often fail, and there is a considerable genetic variability for FER resistance in maize germplasm (Santiago et al 2013, Schwantes et al 2018, genetic improvement might be the optimal strategy in future maize breeding for tolerable fumonisin contamination in food and feed (Maschietto et al 2017). To date, many QTL studies were conducted in populations with low-density genetic maps, and QTL studies in densely mapped populations are rare (Lanubile et al 2017).…”

Priming to protect maize from Fusarium verticillioides and its fumonisin accumulation

“…Recently, other researchers have identified eight QTLs and 43 genes associated with F. verticillioides seed rot resistance through linkage mapping and GWAS respectively . By combining transcriptomic data with QTLs proposed 24 candidate genes for resistance to F. verticillioides were identified, allowing to make possible the selection of genotypes with both low disease severity and low fumonisin contamination …”

“…14 By combining transcriptomic data with QTLs proposed 24 candidate genes for resistance to F. verticillioides were identified, allowing to make possible the selection of genotypes with both low disease severity and low fumonisin contamination. 15 The physiological health of the plantlets may also affect the development of symptoms, 9 and induction of the priming state in the plant through the application of Chamae on seeds could be another way to prepare plants against pathogen attacks. The aim of the present work was to characterize the influence of this commercial natural fertilizer based on extracts obtaines from plant decoctions, Chamae, on early colonization of germinating seeds and plantlets by F. verticillioides and the development of symptoms, including fumonisin accumulation, and the influence of treatments on yield.…”