scholarly journals Complex Genetic System Involved in Fusarium Ear Rot Resistance in Maize as Revealed by GWAS, Bulked Sample Analysis, and Genomic Prediction

Plant Disease ◽  
2020 ◽  
Vol 104 (6) ◽  
pp. 1725-1735 ◽  
Author(s):  
Zifeng Guo ◽  
Cheng Zou ◽  
Xiaogang Liu ◽  
Shanhong Wang ◽  
Wen-Xue Li ◽  
...  

Fusarium ear rot (FER) caused by Fusarium verticillioides is one of the most prevalent maize diseases in China and worldwide. Resistance to FER is a complex trait controlled by multiple genes highly affected by environment. In this paper, genome-wide association study (GWAS), bulked sample analysis (BSA), and genomic prediction were performed for understanding FER resistance using 509 diverse inbred lines, which were genotyped by 37,801 high-quality single-nucleotide polymorphisms (SNPs). Ear rot evaluation was performed using artificial inoculation in four environments in China: Xinxiang, Henan, and Shunyi, Beijing, during 2017 and 2018. Significant phenotypic and genetic variation for FER severity was observed, and FER resistance was significantly correlated among the four environments with a generalized heritability of 0.78. GWAS identified 23 SNPs that were associated with FER resistance, 2 of which (1_226233417 on chromosome 1 and 10_14501044 on chromosome 10) were associated at threshold of 2.65 × 10−7 [−log(0.01/37,801)]. Using BSA, resistance quantitative trait loci were identified on chromosomes 3, 4, 7, 9, and 10 at the 90% confidence level and on chromosomes 3 and 10 at the 95% confidence level. A key region, bin 10.03, was detected by both GWAS and BSA. Genomic prediction for FER resistance showed that the prediction accuracy by trait-related markers was higher than that by randomly selected markers under different levels of marker density. Marker-assisted selection using genomic prediction could be an efficient strategy for genetic improvement for complex traits like FER resistance.




2016 ◽  
Vol 6 (12) ◽  
pp. 3803-3815 ◽  
Author(s):  
Jiafa Chen ◽  
Rosemary Shrestha ◽  
Junqiang Ding ◽  
Hongjian Zheng ◽  
Chunhua Mu ◽  
...  

Abstract Fusarium ear rot (FER) incited by Fusarium verticillioides is a major disease of maize that reduces grain quality globally. Host resistance is the most suitable strategy for managing the disease. We report the results of genome-wide association study (GWAS) to detect alleles associated with increased resistance to FER in a set of 818 tropical maize inbred lines evaluated in three environments. Association tests performed using 43,424 single-nucleotide polymorphic (SNPs) markers identified 45 SNPs and 15 haplotypes that were significantly associated with FER resistance. Each associated SNP locus had relatively small additive effects on disease resistance and accounted for 1–4% of trait variation. These SNPs and haplotypes were located within or adjacent to 38 candidate genes, 21 of which were candidate genes associated with plant tolerance to stresses, including disease resistance. Linkage mapping in four biparental populations to validate GWAS results identified 15 quantitative trait loci (QTL) associated with F. verticillioides resistance. Integration of GWAS and QTL to the maize physical map showed eight colocated loci on chromosomes 2, 3, 4, 5, 9, and 10. QTL on chromosomes 2 and 9 are new. These results reveal that FER resistance is a complex trait that is conditioned by multiple genes with minor effects. The value of selection on identified markers for improving FER resistance is limited; rather, selection to combine small effect resistance alleles combined with genomic selection for polygenic background for both the target and general adaptation traits might be fruitful for increasing FER resistance in maize.



Crop Science ◽  
2020 ◽  
Vol 60 (6) ◽  
pp. 2867-2881
Author(s):  
Maurício Carlos Kuki ◽  
Ronald José Barth Pinto ◽  
Filipe Augusto Bengosi Bertagna ◽  
Dauri José Tessmann ◽  
Antônio Teixeira do Amaral ◽  
...  


Plant Disease ◽  
2005 ◽  
Vol 89 (3) ◽  
pp. 291-297 ◽  
Author(s):  
C. E. Kleinschmidt ◽  
M. J. Clements ◽  
C. M. Maragos ◽  
J. K. Pataky ◽  
D. G. White

Fumonisins produced by Fusarium verticillioides (syn = F. moniliforme) and F. proliferatum have been associated with potentially serious toxicoses of animals and humans. Thus, hybrids with low fumonisin accumulation in grain will be valuable for the production of corn-based human food products. We evaluated 68 food-grade dent corn hybrids for severity of Fusarium ear rot and fumonisin accumulation in grain in inoculated trials in Urbana, IL in 2000 and 2001. Our inoculation technique was successful in initiating fumonisin accumulation that allowed discrimination among hybrids. We identified several hybrids that could have acceptable levels (<4 μg/g) of fumonisin accumulation in Illinois in most years. Twenty-six hybrids with low or high fumonisin accumulation in 2000 were reevaluated in noninoculated trials at three locations in Illinois in 2001. Fumonisin concentration in grain at all three locations was relatively low; thus, separation of hybrids was poor. At two locations, those hybrids with the highest fumonisin concentration in grain also had high concentrations following inoculation. However, one hybrid that had relatively low fumonisin concentration following inoculation had unacceptable levels of fumonisin (5 μg/g) in natural conditions. Therefore, hybrids need to be evaluated by inoculation and further evaluated at locations where the environment favors fumonisin accumulation.



Author(s):  
Yong-Soon Park ◽  
Eli J Borrego ◽  
Xiquan Gao ◽  
Shawn A Christensen ◽  
Eric Schmelz ◽  
...  

Seed maceration and contamination with mycotoxin fumonisin inflicted by Fusarium verticillioides is major disease of concern for maize producers world-wide. Meta-analyses of QTL for Fusarium ear rot resistance uncovered several ethylene (ET) biosynthesis and signaling genes within them, implicating ET in maize interactions with F. verticillioides. We tested this hypothesis using maize knock-out mutants of the 1-aminocyclopropane-1-carboxylate (ACC) synthases, ZmACS2 and ZmACS6. Infected wild-type seed emitted five-fold higher ET levels compared to controls, whereas ET was abolished in the acs2 and acs6 single and double mutants. The mutants supported reduced fungal biomass, conidia and fumonisin content. Normal susceptibility was restored in the acs6 mutant with exogenous treatment of ET precursor, ACC. Subsequently, we showed that fungal G-protein signaling is required for virulence via induction of maize-produced ET. F. verticillioides Gβ subunit and two regulators of G-protein signaling mutants displayed reduced seed colonization and decreased ET levels. These defects were rescued by exogenous application of ACC. We concluded that pathogen-induced ET facilitates F. verticillioides colonization of seed, and in turn host ET production is manipulated via G-protein signaling of F. verticillioides to facilitate pathogenesis.



2021 ◽  
Vol 15 ◽  
Author(s):  
Hayley S. Mountford ◽  
Amanda Hill ◽  
Anna L. Barnett ◽  
Dianne F. Newbury

The ability to finely control our movement is key to achieving many of the educational milestones and life-skills we develop throughout our lives. Despite the centrality of coordination to early development, there is a vast gap in our understanding of the underlying biology. Like most complex traits, both genetics and environment influence motor coordination, however, the specific genes, early environmental risk factors and molecular pathways are unknown. Previous studies have shown that about 5% of school-age children experience unexplained difficulties with motor coordination. These children are said to have Developmental Coordination Disorder (DCD). For children with DCD, these motor coordination difficulties significantly impact their everyday life and learning. DCD is associated with poorer academic achievement, reduced quality of life, it can constrain career opportunities and increase the risk of mental health issues in adulthood. Despite the high prevalence of coordination difficulties, many children remain undiagnosed by healthcare professionals. Compounding under-diagnosis in the clinic, research into the etiology of DCD is severely underrepresented in the literature. Here we present the first genome-wide association study to examine the genetic basis of early motor coordination in the context of motor difficulties. Using data from the Avon Longitudinal Study of Parents and Children we generate a derived measure of motor coordination from four components of the Movement Assessment Battery for Children, providing an overall measure of coordination across the full range of ability. We perform the first genome-wide association analysis focused on motor coordination (N = 4542). No single nucleotide polymorphisms (SNPs) met the threshold for genome-wide significance, however, 59 SNPs showed suggestive associations. Three regions contained multiple suggestively associated SNPs, within five preliminary candidate genes: IQSEC1, LRCC1, SYNJ2B2, ADAM20, and ADAM21. Association to the gene IQSEC1 suggests a potential link to axon guidance and dendritic projection processes as a potential underlying mechanism of motor coordination difficulties. This represents an interesting potential mechanism, and whilst further validation is essential, it generates a direct window into the biology of motor coordination difficulties. This research has identified potential biological drivers of DCD, a first step towards understanding this common, yet neglected neurodevelopmental disorder.



2018 ◽  
Vol 51 (17-18) ◽  
pp. 939-950
Author(s):  
Olumayowa Mary Olowe ◽  
Ayodele Adegboyega Sobowale ◽  
Odunayo Joseph Olawuyi ◽  
Adegboyega Christopher Odebode


2020 ◽  
Vol 116 (11/12) ◽  
Author(s):  
Maryke Craven ◽  
Liesl Morey ◽  
Liesl Morey ◽  
Adrian Abrahams ◽  
Henry A. Njom ◽  
...  

Northern corn leaf blight (NCLB) caused by Exserohilum turcicum and Fusarium ear rot caused by Fusarium verticillioides, are economically important maize diseases in South Africa. The effect of induced plant stress by NCLB on F. verticillioides ear rot and fumonisin production is unknown. Four field trials were conducted during 2016/2017 and 2017/2018 (November and December planting dates) at the Agricultural Research Council – Grain Crops in Potchefstroom (South Africa). Three maize cultivars with varying resistance levels to NCLB were selected (IMP50-10B – susceptible, BG3292 – moderately susceptible, DKC 61-94BR – resistant). NCLB severities were created through eight treatments: TMT1 – maximum control (three fungicide applications); TMT2 – standard control (two fungicide applications) and TMT3 – natural control (not inoculated or sprayed). The remaining treatments were inoculated with a cocktail of five NCLB races (Race 3, 3N, 23, 23N and 13N): TMT4 (five weeks after planting / WAP); TMT5 (five and six WAP); TMT6 (five, six and seven WAP); TMT7 (six and seven WAP); and TMT8 (seven WAP). Maize ears were naturally infected with F. verticillioides. Fifteen random plants were labelled at dent stage and NCLB severity (%), area under the disease progress curve, ear rot diseased area, ear rot severity (%), ear rot incidence (%) and total fumonisins (FB1+FB2+FB3; ug/kg) were established. Low levels of cob rot severity and fumonisins were obtained in all four trials. NCLB severity did not affect ear rot related parameters measured. Mean fumonisin levels were below the South African tolerance levels. Fumonisin concentrations differed significantly between cultivars but was not affected by NCLB severity or the cultivar x treatment interaction.





Toxins ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 86 ◽  
Author(s):  
Laura Morales ◽  
Charles T. Zila ◽  
Danilo E. Moreta Mejía ◽  
Melissa Montoya Arbelaez ◽  
Peter J. Balint-Kurti ◽  
...  

The fungus Fusarium verticillioides can infect maize ears, causing Fusarium ear rot (FER) and contaminating the grain with fumonisins (FUM), which are harmful to humans and animals. Breeding for resistance to FER and FUM and post-harvest sorting of grain are two strategies for reducing FUM in the food system. Kernel and cob tissues have been previously associated with differential FER and FUM. Four recombinant inbred line families from the maize nested associated mapping population were grown and inoculated with F. verticillioides across four environments, and we evaluated the kernels for external and internal infection severity as well as FUM contamination. We also employed publicly available phenotypes on innate ear morphology to explore genetic relationships between ear architecture and resistance to FER and FUM. The four families revealed wide variation in external symptomatology at the phenotypic level. Kernel bulk density under inoculation was an accurate indicator of FUM levels. Genotypes with lower kernel density—under both inoculated and uninoculated conditions—and larger cobs were more susceptible to infection and FUM contamination. Quantitative trait locus (QTL) intervals could be classified as putatively resistance-specific and putatively shared for ear and resistance traits. Both types of QTL mapped in this study had substantial overlap with previously reported loci for resistance to FER and FUM. Ear morphology may be a component of resistance to F. verticillioides infection and FUM accumulation.



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