scholarly journals Unravelling Differences in Candidate Genes for Drought Tolerance in Potato (Solanum tuberosum L.) by Use of New Functional Microsatellite Markers

Genes ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 494
Author(s):  
Christina Schumacher ◽  
Christoph Tim Krannich ◽  
Lisa Maletzki ◽  
Karin Köhl ◽  
Joachim Kopka ◽  
...  
Keyword(s):  
Drought Tolerance ◽  
Candidate Genes ◽  
Ssr Markers ◽  
Polymorphic Information Content ◽  
Association Studies ◽  
Solanum Tuberosum L ◽  
Potato Cultivars ◽  
Candidate Gene Approach ◽  
Improved Performance ◽  
High Yields

Potato is regarded as drought sensitive and most vulnerable to climate changes. Its cultivation in drought prone regions or under conditions of more frequent drought periods, especially in subtropical areas, requires intensive research to improve drought tolerance in order to guarantee high yields under limited water supplies. A candidate gene approach was used to develop functional simple sequence repeat (SSR) markers for association studies in potato with the aim to enhance breeding for drought tolerance. SSR primer combinations, mostly surrounding interrupted complex and compound repeats, were derived from 103 candidate genes for drought tolerance. Validation of the SSRs was performed in an association panel representing 34 mainly starch potato cultivars. Seventy-five out of 154 SSR primer combinations (49%) resulted in polymorphic, highly reproducible banding patterns with polymorphic information content (PIC) values between 0.11 and 0.90. Five SSR markers identified allelic differences between the potato cultivars that showed significant associations with drought sensitivity. In all cases, the group of drought-sensitive cultivars showed predominantly an additional allele, indicating that selection against these alleles by marker-assisted breeding might confer drought tolerance. Further studies of these differences in the candidate genes will elucidate their role for an improved performance of potatoes under water-limited conditions.

scholarly journals Dissection of Maize Drought Tolerance at the Flowering Stage Using Ge-Nome-Wide Association Study

2021 ◽  
Author(s):  
Siffat Ullah Khan ◽  
Yanxiao Zheng ◽  
Zaid Chachar ◽  
Xuhuan Zhang ◽  
Guyi Zhou ◽  
...  
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Candidate Genes ◽  
Pyridoxal Phosphate ◽  
Association Studies ◽  
26S Proteasome ◽  
Regulatory Subunit ◽  
Tolerance Index ◽  
Genome Wide Association Studies ◽  
Flowering Stage

Abstract Drought is one of the most critical environmental factors constraining corn production especially when it occurs during flowering, resulting in serious yield losses. In this study, anthesis to silk interval (ASI), plant height (PH), and ear biomass at the silking date (EBM) of 279 inbred lines were evaluated under water-stress (WS) and well-water (WW) field conditions for three consecutive years. Averagely, ASI was extended by 25.96%, ear biomass was decreased by 17.54%, and the PH was reduced by 12.47% under drought stress conditions. Genome wide association studies (GWAS) were carried out using phenotypic values under WS, WW and drought-tolerance index (WS-WW or WS/WW) applying mixed linear model controlling both population structure and relative kinship. Totally, 71, 159, and 21 SNPs were significantly (P < 10-5) associated with ASI, ear biomass, and PH, respectively. Candidate genes encoding ARABIDILLO 1 protein, glycoprotein, Tic22-like and Zinc finger family protein for ASI, and 26S proteasome non-ATPase regulatory subunit-9 for EBM, were identified under both WW and WS conditions. Pyridoxal phosphate transferase was associated with EBM under drought stress treatment in consecutive two years. Furthermore, most candidate genes were evidenced to be drought responsive in the association panel. Meanwhile, the favourable/drought tolerance haplotypes were identified based on haplotype analysis. These findings provide insights into the genetic basis of drought tolerance at the flowering stage especially for the female inflorescence development and will facilitate high drought tolerant maize breeding.

Population structure, marker-trait association and identification of candidate genes for terminal heat stress relevant traits in bread wheat (Triticum aestivum L. em Thell)

2020 ◽  
Vol 18 (3) ◽  
pp. 168-178
Author(s):  
Devender Sharma ◽  
Jai Prakash Jaiswal ◽  
Navin Chander Gahtyari ◽  
Anjana Chauhan ◽  
Rashmi Chhabra ◽  
...  
Keyword(s):  
Population Structure ◽  
Heat Stress ◽  
Candidate Genes ◽  
Bread Wheat ◽  
Ssr Markers ◽  
Stress Responses ◽  
Vegetation Index ◽  
Association Studies ◽  
Trait Association

AbstractGenetic improvement along with widened crop base necessitates for the detailed understanding of the genetic diversity and population structure in wheat. The present investigation reports the discovery of a total of 182 alleles by assaying 52 simple sequence repeats (SSRs) on 40 genotypes of bread wheat. Unweighted neighbour-joining method grouped these genotypes into two main clusters. Highly heat tolerant and intermediate tolerant cultivars were grouped in the same cluster, whereas remaining genotypes, particularly sensitive ones, were assigned different cluster. Similarly, the entire population was structured into two sub-populations (K = 2), closely corresponding with the other distance-based clustering patterns. The marker-trait association was discovered for four important physiological parameters, viz. canopy temperature depression, membrane thermostability index (MSI), normalized difference vegetation index and heat susceptibility index, indicating for heat stress (HS) tolerance in wheat. Both general and mixed linear models of association studies during 2017 and 2018, revealed the association of SSR markers, wmc222 (17.60%, PV) and gwm34 (20.70%, PV) with the mean phenotypic value of MSI. Likewise, SSR markers barc183, gwm75, gwm11 and cfd7 revealed a unique relationship with four selected physiological traits. Candidate genes discovered using in silico tools had nine SSR markers within the genic regions reported to play a role in heat and drought stress responses in plants. The information generated about these genic regions may be explored further in expression studies in-vivo to impart HS tolerance in bread wheat.

Development of SSR markers and association studies of markers with phenology and yield-related traits in grass pea (Lathyrus sativus)

2020 ◽  
Vol 71 (8) ◽  
pp. 768
Author(s):  
Khela Ram Soren ◽  
Aravind Kumar Konda ◽  
Priyanka Gangwar ◽  
Vijay A. Tiwari ◽  
P. S. Shanmugavadivel ◽  
...  
Keyword(s):  
Ssr Markers ◽  
Low Income ◽  
Polymorphic Information Content ◽  
Association Studies ◽  
Crop Improvement ◽  
Plant Phenology ◽  
Lathyrus Sativus ◽  
Low Income Countries ◽  
Grass Pea ◽  
Agricultural Ecosystem

Grass pea (Lathyrus sativus L.) is an important food crop cultivated in dryland agricultural ecosystem. It is an important source of dietary protein to millions of people living in low-income countries in South-east Asia and Africa. The present study emphasises the development of genomic resources and their application in marker–trait association for plant phenology and yield-related traits in lathyrus. In silico mining of nucleotide sequences identified 203 simple sequence repeat (SSR) motifs, of which trimer repeats (62%) were most abundant followed by tetramer (19%), hexamer (10%), pentamer (6%) and dimer (3%) nucleotide repeats. Of 150 SSR markers screened, 60 markers were amplified 75 alleles from 50 germplasm lines with 2–3 alleles per locus and the polymorphic information content of 0.45 was observed. We report 6 significant marker–trait associations using the developed SSR markers for plant phenology and yield-related traits following mixed linear model (Q+K) analysis. Gene ontology search of trait linked markers revealed marker regions encoding genes related to homeobox-leucine zipper protein ATHB-6-like, rubredoxin family protein, and cationic peroxidise. Understanding the association of novel alleles in trait expression will play a significant role in future lathyrus crop improvement programmes.

scholarly journals Genetic Diversity Assessment in Pea (Pisum sativum L.) using Microsatellite Markers

2021 ◽  
Vol 12 (5) ◽  
pp. 402-408
Author(s):  
Hanuman Ram ◽  
Keyword(s):  
Genetic Diversity ◽  
Microsatellite Markers ◽  
Ssr Markers ◽  
Molecular Diversity ◽  
Polymorphic Information Content ◽  
Association Studies ◽  
Pisum Sativum L ◽  
Diversity Assessment ◽  
Potential Use ◽  
Simple Sequence

The present study was conducted on genetic diversity analyses among 24 pea genotypes during 2017–2018 to assess the molecular diversity of pea genotypes using SSR markers. Out of 62, eleven markers were found to be polymorphic and the polymorphic information content (PIC) of the simple sequence repeat (SSR) markers ranged from 0.19 to as high as 0.64. Molecular profiling of these genotypes using 11 SSRs distributed throughout the genome generated 32 alleles with a mean of 2.91 alleles per locus. The genetic dissimilarity based on simple matching coefficient for 24 genotypes ranged from 0.00 to 0.91 with an average of 0.52. Cluster analyses grouped 24 genotypes into two major clusters with one outlier and supported by principal coordinate analysis (PCoA) in which genotypes were distributed across four quadrangles. Analysis of molecular variance (AMOVA) showed significant estimated value at degree of 1000 permutations. Percentage of variability was higher among individual (67%) than among populations (11%). Percentage of variability within individual was also higher (22%) than among populations (11%). Pop1 (I=0.707, He=0.446, and uHe=0.466) shows higher diversity than pop2 (I=0.630, He=0.381 and uHe=0.398). The percentage of polymorphic loci per population (PPL) ranged from 81.82% (pop2) to 90.91% (pop1) with an average of 86.36%. The present study demonstrates the utility of microsatellite markers for estimating molecular diversity as well as genotype identification in pea. This study also suggests a potential use of these markers in further association studies.

scholarly journals Genetic Diversity Among Some Rice Genotypes with Different Drought Tolerance based on SSR Markers

2016 ◽  
Vol 49 (3) ◽  
pp. 39-50 ◽  
Author(s):  
H.A. Freeg ◽  
G.B. Anis ◽  
A.A. Abo-Shousha ◽  
A.N. El-Banna ◽  
A. El-Sabagh
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Drought Tolerance ◽  
Ssr Markers ◽  
Polymorphic Information Content ◽  
Allelic Diversity ◽  
Similarity Coefficients ◽  
Wide Range ◽  
Single Marker ◽  
Rice Genotypes

Abstract Rice is the most important food crop for the developing world. Hence, identifying rice genotypes to drought tolerance for using as donors in breeding is one of the most important challenges for rice research. Therefore, Molecular markers are useful tools to determine genetic diversity and identifying rice genotypes to drought tolerance. In the present study, A number of 41 rice genotypes with different drought tolerance from different geographic locations were evaluated for genetic diversity by using 15 SSR markers. A total of 68 alleles were detected of which 61(89.79%) were polymorphic. The number of alleles detected by a single marker varied from 2 to 8 alleles with an average of 4.71 alleles per locus. The polymorphic information content (PIC) values ranged from 0.07 (RM219) to 0.80 (RM263) with an average of 0.52. Genetic similarity coefficients of pair wise comparisons were estimated on the basis of the polymorphic microsatelite loci ranged from 0.23 to 0.91 indicating a wide range of genetic variation present among the studied genotypes. It was determined that the primers RM20A, RM302, RM212 and RM286 could be useful for selecting drought tolerant lines through MAS approach. The most significant application of these identified major QTLs for drought tolerance is to collect those favorable alleles into elite local line through marker assisted breeding. The results indicated the ability of SSR markers to identify the allelic diversity and genetic variation among the studied rice genotypes. These results recommended for using this material in future breeding programs to provide important source of genetic diversity for drought tolerance in rice.

scholarly journals Development of EST-SSR Markers Linked to Flowering Candidate Genes in Elymus sibiricus L. Based on RNA Sequencing

Plants ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1371
Author(s):  
Yuying Zheng ◽  
Zongyu Zhang ◽  
Yiyang Wan ◽  
Jiaoyang Tian ◽  
Wengang Xie
Keyword(s):  
Candidate Genes ◽  
Ssr Markers ◽  
Structure Analysis ◽  
Expressed Sequence Tag ◽  
Polymorphic Information Content ◽  
Heading Date ◽  
Group Method ◽  
Late Flowering ◽  
Elymus Sibiricus ◽  
Population Structure Analysis

Elymus sibiricus L. is an important cold-season grass with excellent cold and drought tolerance, good palatability, and nutrition. Flowering time is a key trait that affects forage and seed yield. Development of EST-SSR (expressed sequence tag simple sequence repeat) markers based on flowering genes contributes to the improvement of flowering traits. In the study, we detected 155 candidate genes related to flowering traits from 10,591 unigenes via transcriptome sequencing in early- and late-flowering genotypes. These candidate genes were mainly involved in the photoperiodic pathway, vernalization pathway, central integrator, and gibberellin pathway. A total of 125 candidate gene-based EST-SSRs were developed. Further, 15 polymorphic EST-SSRs closely associated to 13 candidate genes were used for genetic diversity and population structure analysis among 20 E. sibiricus accessions, including two contrasting panels (early-flowering and late-flowering). Among them, primer 28366, designed from heading date 3a (HD3a), effectively distinguished early- and late-flowering genotypes using a specifically amplified band of 175 bp. The polymorphic information content (PIC) value ranged from 0.12 to 0.48, with an average of 0.25. The unweighted pair group method analysis (UPGMA) cluster and structure analysis showed that the 20 E. sibiricus genotypes with similar flowering times tended to group together. These newly developed EST-SSR markers have the potential to be used for molecular markers assisted selection and germplasm evaluation of flowering traits in E. sibiricus.

scholarly journals Using SSR Markers For Assessment Genetic Diversity And Detection Drought Escape Candidate Genes In Barley Lines (Hordeum Vulgare L.)

2014 ◽  
Vol 70 (1) ◽  
pp. 3-14 ◽  
Author(s):  
Vahideh Gougerdchi ◽  
Sara Dezhsetan ◽  
Mohammad Ali Ebrahimi ◽  
Behzad Sadeghzadeh ◽  
Sona Savari
Keyword(s):  
Genetic Diversity ◽  
Cluster Analysis ◽  
Molecular Markers ◽  
Candidate Genes ◽  
Ssr Markers ◽  
Polymorphic Information Content ◽  
Marker Assisted Breeding ◽  
Hordeum Vulgare L ◽  
Breeding Programs ◽  
Mapping Analysis

Abstract Assessment of genetic diversity using molecular markers is one of the primary and important steps in breeding programs. In this study, genetic diversity of 52 barley lines evaluated using 68 SSR primer pairs and 47 primer pairs produced clear and polymorphic banding pattern. In general, 153 polymorphic alleles detected. The number of observed polymorphic alleles varied from 2 to 9, with an average of 3.26 alleles per locus. Polymorphic Information Content (PIC) ranged from 0.07 to 0.81, with an average of 0.45. In this research, SSR markers differentiated the studied lines efficiently. Using cluster analysis, studied barley lines divided into two groups. Genetic diversity was relatively corresponding with geographical origins, because the lines related to a country somewhat diverged from each other. Two-rowed Iranian and Chinese barleys classified in one subgroup. Also, most six-rowed barleys classified in one subgroup. Association mapping analysis was used to identify candidate genes for drought escape in barley lines and 16 informative markers were identified after which confirmation in other tests could be suitable for marker assisted breeding drought escape.

scholarly journals A meta-analysis of genome-wide association studies for average daily gain and lean meat percentage in two Duroc pig populations

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Shenping Zhou ◽  
Rongrong Ding ◽  
Fanming Meng ◽  
Xingwang Wang ◽  
Zhanwei Zhuang ◽  
...  
Keyword(s):  
Candidate Genes ◽  
Growth And Development ◽  
Genetic Architecture ◽  
Association Studies ◽  
Meta Analysis ◽  
Average Daily Gain ◽  
Genome Wide Association ◽  
Genome Wide Association Studies ◽  
Genome Wide ◽  
Daily Gain

Abstract Background Average daily gain (ADG) and lean meat percentage (LMP) are the main production performance indicators of pigs. Nevertheless, the genetic architecture of ADG and LMP is still elusive. Here, we conducted genome-wide association studies (GWAS) and meta-analysis for ADG and LMP in 3770 American and 2090 Canadian Duroc pigs. Results In the American Duroc pigs, one novel pleiotropic quantitative trait locus (QTL) on Sus scrofa chromosome 1 (SSC1) was identified to be associated with ADG and LMP, which spans 2.53 Mb (from 159.66 to 162.19 Mb). In the Canadian Duroc pigs, two novel QTLs on SSC1 were detected for LMP, which were situated in 3.86 Mb (from 157.99 to 161.85 Mb) and 555 kb (from 37.63 to 38.19 Mb) regions. The meta-analysis identified ten and 20 additional SNPs for ADG and LMP, respectively. Finally, four genes (PHLPP1, STC1, DYRK1B, and PIK3C2A) were detected to be associated with ADG and/or LMP. Further bioinformatics analysis showed that the candidate genes for ADG are mainly involved in bone growth and development, whereas the candidate genes for LMP mainly participated in adipose tissue and muscle tissue growth and development. Conclusions We performed GWAS and meta-analysis for ADG and LMP based on a large sample size consisting of two Duroc pig populations. One pleiotropic QTL that shared a 2.19 Mb haplotype block from 159.66 to 161.85 Mb on SSC1 was found to affect ADG and LMP in the two Duroc pig populations. Furthermore, the combination of single-population and meta-analysis of GWAS improved the efficiency of detecting additional SNPs for the analyzed traits. Our results provide new insights into the genetic architecture of ADG and LMP traits in pigs. Moreover, some significant SNPs associated with ADG and/or LMP in this study may be useful for marker-assisted selection in pig breeding.

scholarly journals A gene co-association network regulating gut microbial communities in a Duroc pig population

Microbiome ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Antonio Reverter ◽  
Maria Ballester ◽  
Pamela A. Alexandre ◽  
Emilio Mármol-Sánchez ◽  
Antoni Dalmau ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Candidate Genes ◽  
Relative Abundance ◽  
Association Studies ◽  
Single Gene ◽  
Host Genome ◽  
Genome Wide Association Studies ◽  
Vaccine Response ◽  
Microbiome Composition ◽  
Host Genetic

Abstract Background Analyses of gut microbiome composition in livestock species have shown its potential to contribute to the regulation of complex phenotypes. However, little is known about the host genetic control over the gut microbial communities. In pigs, previous studies are based on classical “single-gene-single-trait” approaches and have evaluated the role of host genome controlling gut prokaryote and eukaryote communities separately. Results In order to determine the ability of the host genome to control the diversity and composition of microbial communities in healthy pigs, we undertook genome-wide association studies (GWAS) for 39 microbial phenotypes that included 2 diversity indexes, and the relative abundance of 31 bacterial and six commensal protist genera in 390 pigs genotyped for 70 K SNPs. The GWAS results were processed through a 3-step analytical pipeline comprised of (1) association weight matrix; (2) regulatory impact factor; and (3) partial correlation and information theory. The inferred gene regulatory network comprised 3561 genes (within a 5 kb distance from a relevant SNP–P < 0.05) and 738,913 connections (SNP-to-SNP co-associations). Our findings highlight the complexity and polygenic nature of the pig gut microbial ecosystem. Prominent within the network were 5 regulators, PRDM15, STAT1, ssc-mir-371, SOX9 and RUNX2 which gathered 942, 607, 588, 284 and 273 connections, respectively. PRDM15 modulates the transcription of upstream regulators of WNT and MAPK-ERK signaling to safeguard naive pluripotency and regulates the production of Th1- and Th2-type immune response. The signal transducer STAT1 has long been associated with immune processes and was recently identified as a potential regulator of vaccine response to porcine reproductive and respiratory syndrome. The list of regulators was enriched for immune-related pathways, and the list of predicted targets includes candidate genes previously reported as associated with microbiota profile in pigs, mice and human, such as SLIT3, SLC39A8, NOS1, IL1R2, DAB1, TOX3, SPP1, THSD7B, ELF2, PIANP, A2ML1, and IFNAR1. Moreover, we show the existence of host-genetic variants jointly associated with the relative abundance of butyrate producer bacteria and host performance. Conclusions Taken together, our results identified regulators, candidate genes, and mechanisms linked with microbiome modulation by the host. They further highlight the value of the proposed analytical pipeline to exploit pleiotropy and the crosstalk between bacteria and protists as significant contributors to host-microbiome interactions and identify genetic markers and candidate genes that can be incorporated in breeding program to improve host-performance and microbial traits.

scholarly journals Genetic Diversity of Selected Rice Genotypes under Water Stress Conditions

Plants ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 27
Author(s):  
Mahmoud M. Gaballah ◽  
Azza M. Metwally ◽  
Milan Skalicky ◽  
Mohamed M. Hassan ◽  
Marian Brestic ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Water Stress ◽  
Drought Stress ◽  
Drought Tolerance ◽  
Ssr Markers ◽  
Similarity Index ◽  
Stress Conditions ◽  
Yield Potential ◽  
Drought Tolerant ◽  
Rice Genotypes

Drought is the most challenging abiotic stress for rice production in the world. Thus, developing new rice genotype tolerance to water scarcity is one of the best strategies to achieve and maximize high yield potential with water savings. The study aims to characterize 16 rice genotypes for grain and agronomic parameters under normal and drought stress conditions, and genetic differentiation, by determining specific DNA markers related to drought tolerance using Simple Sequence Repeats (SSR) markers and grouping cultivars, establishing their genetic relationship for different traits. The experiment was conducted under irrigated (normal) and water stress conditions. Mean squares due to genotype × environment interactions were highly significant for major traits. For the number of panicles/plants, the genotypes Giza179, IET1444, Hybrid1, and Hybrid2 showed the maximum mean values. The required sterility percentage values were produced by genotypes IET1444, Giza178, Hybrid2, and Giza179, while, Sakha101, Giza179, Hybrid1, and Hybrid2 achieved the highest values of grain yield/plant. The genotypes Giza178, Giza179, Hybrid1, and Hybrid2, produced maximum values for water use efficiency. The effective number of alleles per locus ranged from 1.20 alleles to 3.0 alleles with an average of 1.28 alleles, and the He values for all SSR markers used varied from 0.94 to 1.00 with an average of 0.98. The polymorphic information content (PIC) values for the SSR were varied from 0.83 to 0.99, with an average of 0.95 along with a highly significant correlation between PIC values and the number of amplified alleles detected per locus. The highest similarity coefficient between Giza181 and Giza182 (Indica type) was observed and are susceptible to drought stress. High similarity percentage between the genotypes (japonica type; Sakha104 with Sakha102 and Sakha106 (0.45), Sakha101 with Sakha102 and Sakha106 (0.40), Sakha105 with Hybrid1 (0.40), Hybrid1 with Giza178 (0.40) and GZ1368-S-5-4 with Giza181 (0.40)) was also observed, which are also susceptible to drought stress. All genotypes are grouped into two major clusters in the dendrogram at 66% similarity based on Jaccard’s similarity index. The first cluster (A) was divided into two minor groups A1 and A2, in which A1 had two groups A1-1 and A1-2, containing drought-tolerant genotypes like IET1444, GZ1386-S-5-4 and Hybrid1. On the other hand, the A1-2 cluster divided into A1-2-1 containing Hybrid2 genotype and A1-2-2 containing Giza179 and Giza178 at coefficient 0.91, showing moderate tolerance to drought stress. The genotypes GZ1368-S-5-4, IET1444, Giza 178, and Giza179, could be included as appropriate materials for developing a drought-tolerant variety breeding program. Genetic diversity to grow new rice cultivars that combine drought tolerance with high grain yields is essential to maintaining food security.

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