scholarly journals Quantitative genetic analysis of interactions in the pepper-Phytophthora capsici pathosystem

2021 ◽  
Author(s):  
Gregory Vogel ◽  
Garrett Giles ◽  
Kelly R. Robbins ◽  
Michael A. Gore ◽  
Christine D. Smart

ABSTRACTThe development of pepper cultivars with durable resistance to the oomycete Phytophthora capsici has been challenging due to differential interactions between the species that allow certain pathogen isolates to cause disease on otherwise resistant host genotypes. Currently, little is known about the pathogen genes that are involved in these interactions. To investigate the genetic basis of P. capsici virulence on individual pepper genotypes, we inoculated sixteen pepper accessions – representing commercial varieties, sources of resistance, and host differentials – with 117 isolates of P. capsici, for a total of 1,864 host-pathogen combinations. Analysis of disease outcomes revealed a significant effect of inter-species genotype-by-genotype interactions, although these interactions were quantitative rather than qualitative in scale. Isolates were classified into five pathogen subpopulations, as determined by their genotypes at over 60,000 single-nucleotide polymorphisms (SNPs). While absolute virulence levels on certain pepper accessions significantly differed between subpopulations, a multivariate phenotype reflecting relative virulence levels on certain pepper genotypes compared to others showed the strongest association with pathogen subpopulation. A genome-wide association study (GWAS) identified four pathogen loci significantly associated with virulence, two of which colocalized with putative RXLR effector genes and another with a polygalacturonase gene cluster. All four loci appeared to represent broad-spectrum virulence genes, as significant SNPs demonstrated consistent effects regardless of the host genotype tested. Host genotype-specific virulence variants in P. capsici may be difficult to map via GWAS, perhaps controlled by many genes of small effect or by multiple alleles that have arisen independently at the same loci.

2020 ◽  
Vol 11 ◽  
Author(s):  
Anjan Kumar Pradhan ◽  
Sundeep Kumar ◽  
Amit Kumar Singh ◽  
Neeraj Budhlakoti ◽  
Dwijesh C. Mishra ◽  
...  

Resistance in modern wheat cultivars for stripe rust is not long lasting due to the narrow genetic base and periodical evolution of new pathogenic races. Though nearly 83 Yr genes conferring resistance to stripe rust have been cataloged so far, few of them have been mapped and utilized in breeding programs. Characterization of wheat germplasm for novel sources of resistance and their incorporation into elite cultivars is required to achieve durable resistance and thus to minimize the yield losses. Here, a genome-wide association study (GWAS) was performed on a set of 391 germplasm lines with the aim to identify quantitative trait loci (QTL) using 35K Axiom® array. Phenotypic evaluation disease severity against four stripe rust pathotypes, i.e., 46S119, 110S119, 238S119, and 47S103 (T) at the seedling stage in a greenhouse providing optimal conditions was carried out consecutively for 2 years (2018 and 2019 winter season). We identified, a total of 17 promising QTl which passed FDR criteria. Moreover these 17 QTL identified in the current study were mapped at different genomic locations i.e. 1B, 2A, 2B, 2D, 3A, 3B, 3D, 4B, 5B and 6B. These 17 QTLs identified in the present study might play a key role in marker-assisted breeding for developing stripe rust resistant wheat cultivars.


2021 ◽  
Vol 11 ◽  
Author(s):  
Alex Silva da Cruz ◽  
Danilo Conrado Silva ◽  
Lysa Bernardes Minasi ◽  
Larissa Kamídia de Farias Teixeira ◽  
Flávia Melo Rodrigues ◽  
...  

Milk production phenotypes are the main focus of genetic selection in dairy herds, and although there are many genes identified as related to the biology of these traits in pure breeds, little is known about crossbreed animals. This study aimed to identify potential genes associated with the 305-day milk yield in 337 crossbreed Gir × Holstein (Girolando) animals. Milk production records were genotyped for 45,613 single-nucleotide polymorphisms (SNPs). This dataset was used for a genome-wide association study (GWAS) using the 305-day milk yield adjusted for the fixed effects of herd and year and linear and quadratic effects of age at calving (in days) and calving factor averaged per animal. Genes within the significant SNPs were retrieved from the Bos taurus ARS-UCD1.2 assembly (bosTau9) for gene ontology analysis. In summary, the GWAS identified 52 SNPs associated [p ≤ 10–4, false discovery rate (FDR) = 8.77%] with milk production, including NUB1 and SLC24A2, which were previously described as related to milk production traits in cattle. The results suggest that SNPs associated mainly with NUB1 and SLC24A2 could be useful to understand milk production in Girolando and used as predictive markers for selecting genetic predisposition for milk yield in Girolando.


2019 ◽  
Author(s):  
Yanhong Lou ◽  
Yun Chen ◽  
Zhihao Liu ◽  
Mingjie Sun ◽  
Fei Han ◽  
...  

Abstract Background: Foxtail millet [Setaria italica (L.) P. Beauv.] is a particularly important cereal and fodder crop in arid and semi-arid regions. The genomic variation and alleles underpinning agronomic and quality traits are important for foxtail millet improvement. To better understand the diversity of foxtail millet and facilitate the genetic dissection of its agronomic and quality traits, we used high-quality single nucleotide polymorphisms (SNPs) to perform a genome-wide association study (GWAS). Results: Using genotyping-by-sequencing, 107 foxtail millet accessions were sequenced, and further analysis revealed 72,181 high-quality SNPs, of which 53 were significantly associated with 15 agronomic and quality traits. These SNPs were distributed across the nine chromosomes of foxtail millet; 44 were located in intergenic regions, whereas one and eight SNPs were located in exon and intron regions, respectively. The GWAS revealed that 28 SNPs were associated with a single trait. Conclusions: For some of the significant SNPs, favourable genotypes showed pyramiding effects for several traits. The 53 loci identified in this study will therefore be useful for breeding programs aimed at foxtail millet improvement.


Animals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1531
Author(s):  
Yasemin Öner ◽  
Malena Serrano ◽  
Pilar Sarto ◽  
Laura Pilar Iguácel ◽  
María Piquer-Sabanza ◽  
...  

A genome-wide association study (GWAS) was performed to identify new single nucleotide polymorphisms (SNPs) and genes associated with mastitis resistance in Assaf sheep by using the Illumina Ovine Infinium® HD SNP BeadChip (680K). In total, 6173 records from 1894 multiparous Assaf ewes with at least three test day records and aged between 2 and 7 years old were used to estimate a corrected phenotype for somatic cell score (SCS). Then, 192 ewes were selected from the top (n = 96) and bottom (n = 96) tails of the corrected SCS phenotype distribution to be used in a GWAS. Although no significant SNPs were found at the genome level, four SNPs (rs419096188, rs415580501, rs410336647, and rs424642424) were significant at the chromosome level (FDR 10%) in two different regions of OAR19. The SNP rs419096188 was located in intron 1 of the NUP210 and close to the HDAC11 genes (61 kb apart), while the other three SNPs were totally linked and located 171 kb apart from the ARPP21 gene. These three genes were related to the immune system response. These results were validated in two SNPs (rs419096188 and rs424642424) in the total population (n = 1894) by Kompetitive Allele-Specific PCR (KASP) genotyping. Furthermore, rs419096188 was also associated with lactose content.


2020 ◽  
Vol 126 (7) ◽  
pp. 1193-1202 ◽  
Author(s):  
Sarin Neang ◽  
Marjorie de Ocampo ◽  
James A Egdane ◽  
John Damien Platten ◽  
Abdelbagi M Ismail ◽  
...  

Abstract Background and Aims The ability for salt removal at the leaf sheath level is considered to be one of the major mechanisms associated with salt tolerance in rice. Thus, understanding the genetic control of the salt removal capacity in leaf sheaths will help improve the molecular breeding of salt-tolerant rice varieties and speed up future varietal development to increase productivity in salt-affected areas. We report a genome-wide association study (GWAS) conducted to find single nucleotide polymorphisms (SNPs) associated with salt removal in leaf sheaths of rice. Methods In this study, 296 accessions of a rice (Oryza sativa) diversity panel were used to identify salt removal-related traits and conduct GWAS using 36 901 SNPs. The sheath:blade ratio of Na+ and Cl– concentrations was used to determine the salt removal ability in leaf sheaths. Candidate genes were further narrowed via Gene Ontology and RNA-seq analysis to those whose putative function was likely to be associated with salt transport and were up-regulated in response to salt stress. Key results For the association signals of the Na+ sheath:blade ratio, significant SNPs were found only in the indica sub-population on chromosome 5. Within candidate genes found in the GWAS study, five genes were upregulated and eight genes were downregulated in the internal leaf sheath tissues in the presence of salt stress. Conclusions These GWAS data imply that rice accessions in the indica variety group are the main source of genes and alleles associated with Na+ removal in leaf sheaths of rice under salt stress.


Author(s):  
Ana Lopez-Malvar ◽  
A Butron ◽  
R Malvar ◽  
LD Gomez ◽  
L Faas ◽  
...  

Abstract Background: Cellulosic ethanol derived from fast growing C4 grasses could become an alternative to finite fossil fuels. With the potential to generate a major source of lignocellulosic biomass, maize has gained importance as an outstanding model plant for studying the complex cell wall network, and as a model to optimize crop breeding strategies in bioenergy grasses. A genome-wide association study was conducted using a subset of 408 Recombinant Inbred Lines (RILs) from a Multiparent-Advanced Intercross (MAGIC) Population in order to identify single nucleotide polymorphisms (SNPs) associated with yield and saccharification efficiency of maize stover.Results: We identified 4 SNPs significantly associated with stover yield that corresponded to 4 QTL, and 16 SNPs significantly associated with saccharification efficiency, that could be clustered into 5 QTL. Markers linked to these QTL could be used in marker-assisted selection programs to improve ethanol production. In addition, we have pointed out genes that contain the significant SNPs or are physically close to them. Conclusions: Genes involved in nitrogen assimilation, organ growth, and stress tolerance could be good candidates attending to QTLs for stover yield. On the other hand, for saccharification efficiency we highlight genes implicated in biomass degradation, transcriptional control of monolignol biosynthesis, and lignin polymerization as probable candidate genes in the QTLs involved.


2015 ◽  
Author(s):  
Longchao Zhang ◽  
Xin Liu ◽  
Jing Liang ◽  
Kebin Zhao ◽  
Hua Yan ◽  
...  

Porcine carcass that is approximately 800 mm long may be expected to have one additional vertebra. Therefore, the number of vertebrae in pigs is an economically important trait. To examine the genetic basis of this trait, we genotyped 593 F2 Large White × Minzhu pigs using the Porcine SNP60K BeadChip. A genome-wide association study identified 39 significant single-nucleotide polymorphisms (SNPs) on the chromosomes SSC1 and SSC7. An 8.82-Mb region that contained all 21 significant SNPs on SSC1 harbored the gene NR6A1, previously reported to influence the number of vertebrae in pigs. The remaining 18 significant SNPs on SSC7 were concentrated in a 4.56-Mb region, which was within the quantitative trait loci interval for number of vertebrae. A haplotype sharing analysis refined the locus to a segment of ~637 Kb. The most significant SNP, SIRI0001067, was contained in this refined region on SSC7 and located in one of the introns of TGFB3. As TGFB3 influences the development of vertebrae in mammalian embryos, the gene may be another strong candidate for the number of vertebrae in pigs.


Cells ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 64
Author(s):  
Nikolaj Meisner Vendelbo ◽  
Khalid Mahmood ◽  
Pernille Sarup ◽  
Mogens S. Hovmøller ◽  
Annemarie Fejer Justesen ◽  
...  

Leaf rust constitutes one of the most important foliar diseases in rye (Secale cereale L.). To discover new sources of resistance, we phenotyped 180 lines belonging to a less well-characterized Gülzow germplasm at three field trial locations in Denmark and Northern Germany in 2018 and 2019. We observed lines with high leaf rust resistance efficacy at all locations in both years. A genome-wide association study using 261,406 informative single-nucleotide polymorphisms revealed two genomic regions associated with resistance on chromosome arms 1RS and 7RS, respectively. The most resistance-associated marker on chromosome arm 1RS physically co-localized with molecular markers delimiting Pr3. In the reference genomes Lo7 and Weining, the genomic region associated with resistance on chromosome arm 7RS contained a large number of nucleotide-binding leucine-rich repeat (NLR) genes. Residing in close proximity to the most resistance-associated marker, we identified a cluster of NLRs exhibiting close protein sequence similarity with the wheat leaf rust Lr1 gene situated on chromosome arm 5DL in wheat, which is syntenic to chromosome arm 7RS in rye. Due to the close proximity to the most resistance-associated marker, our findings suggest that the considered leaf rust R gene, provisionally denoted Pr6, could be a Lr1 ortholog in rye.


2010 ◽  
Vol 13 (4) ◽  
pp. 398-403 ◽  
Author(s):  
Miriam A. Mosing ◽  
Karin J. H. Verweij ◽  
Sarah E. Medland ◽  
Jodie Painter ◽  
Scott D. Gordon ◽  
...  

AbstractSelf-rated health questions have been proven to be a highly reliable and valid measure of overall health as measured by other indicators in many population groups. It also has been shown to be a very good predictor of mortality, chronic or severe diseases, and the need for services, and is positively correlated with clinical assessments. Genetic factors have been estimated to account for 25–64% of the variance in the liability of self-rated health. The aim of the present study was to identify Single Nucleotide Polymorphisms (SNPs) underlying the heritability of self-rated health by conducting a genome-wide association analysis in a large sample of 6,706 Australian individuals aged 18–92. No genome wide significant SNPs associated with self-rated health could be identified, indicating that self-rated health may be influenced by a large number of SNPs with very small effect size. A very large sample will be needed to identify these SNPs.


2021 ◽  
pp. 174749302110062
Author(s):  
Bin Yan ◽  
Jian Yang ◽  
Li Qian ◽  
Fengjie Gao ◽  
Ling Bai ◽  
...  

Background: Observational studies have found an association between visceral adiposity and stroke. Aims: The purpose of this study was to investigate the role and genetic effect of visceral adipose tissue (VAT) accumulation on stroke and its subtypes. Methods: In this two-sample Mendelian randomization (MR) study, genetic variants (221 single nucleotide polymorphisms; P<5×10-8) using as instrumental variables for MR analysis was obtained from a genome-wide association study (GWAS) of VAT. The outcome datasets for stroke and its subtypes were obtained from the MEGASTROKE consortium (up to 67,162 cases and 453,702 controls). MR standard analysis (inverse variance weighted method) was conducted to investigate the effect of genetic liability to visceral adiposity on stroke and its subtypes. Sensitivity analysis (MR-Egger, weighted median, MR-PRESSO) were also utilized to assess horizontal pleiotropy and remove outliers. Multi-variable MR analysis was employed to adjust potential confounders. Results: In the standard MR analysis, genetically determined visceral adiposity (per 1 SD) was significantly associated with a higher risk of stroke (odds ratio [OR] 1.30; 95% confidence interval [CI] 1.21-1.41, P=1.48×10-11), ischemic stroke (OR 1.30; 95% CI 1.20-1.41, P=4.01×10-10), and large artery stroke (OR 1.49; 95% CI 1.22-1.83, P=1.16×10-4). The significant association was also found in sensitivity analysis and multi-variable MR analysis. Conclusions: Genetic liability to visceral adiposity was significantly associated with an increased risk of stroke, ischemic stroke, and large artery stroke. The effect of genetic susceptibility to visceral adiposity on the stroke warrants further investigation.


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