Journal articles 2015
Documents
Linkage analysis and map construction in genetic populations of clonal F1 and double cross
Zhang L, Li H and Wang J (2015). Linkage analysis and map construction in genetic populations of clonal F1 and double cross. G3 5(3):427–439 (DOI:10.1534/g3.114.016022). (G8009.10)
Abstract: In this study, we considered four categories of molecular markers based on the number of distinguishable alleles at the marker locus and the number of distinguishable genotypes in clonal F1 progenies. For two marker loci, there are nine scenarios that allow the estimation of female, male, and/or combined recombination frequencies. In a double cross population derived from four inbred lines, five categories of markers are classified and another five scenarios are present for recombination frequency estimation. Theoretical frequencies of identifiable genotypes were given for each scenario, from which the maximum likelihood estimates of one or more of the three recombination frequencies could be estimated. If there was no analytic solution, then Newton-Raphson method was used to acquire a numerical solution. We then proposed to use an algorithm in Traveling Salesman Problem to determine the marker order. Finally, we proposed a procedure to build the two haploids of the female parent and the two haploids of the male parent in clonal F1. Once the four haploids were built, clonal F1 hybrids could be exactly regarded as a double cross population. Efficiency of the proposed methods was demonstrated in simulated clonal F1 populations and one actual maize double cross. Extensive comparisons with software JoinMap4.1, OneMap, and R/qtl show that the methodology proposed in this article can build more accurate linkage maps in less time.
Zhang L, Li H and Wang J (2015). Linkage analysis and map construction in genetic populations of clonal F1 and double cross. G3 5(3):427–439 (DOI:10.1534/g3.114.016022). (G8009.10)
Abstract: In this study, we considered four categories of molecular markers based on the number of distinguishable alleles at the marker locus and the number of distinguishable genotypes in clonal F1 progenies. For two marker loci, there are nine scenarios that allow the estimation of female, male, and/or combined recombination frequencies. In a double cross population derived from four inbred lines, five categories of markers are classified and another five scenarios are present for recombination frequency estimation. Theoretical frequencies of identifiable genotypes were given for each scenario, from which the maximum likelihood estimates of one or more of the three recombination frequencies could be estimated. If there was no analytic solution, then Newton-Raphson method was used to acquire a numerical solution. We then proposed to use an algorithm in Traveling Salesman Problem to determine the marker order. Finally, we proposed a procedure to build the two haploids of the female parent and the two haploids of the male parent in clonal F1. Once the four haploids were built, clonal F1 hybrids could be exactly regarded as a double cross population. Efficiency of the proposed methods was demonstrated in simulated clonal F1 populations and one actual maize double cross. Extensive comparisons with software JoinMap4.1, OneMap, and R/qtl show that the methodology proposed in this article can build more accurate linkage maps in less time.
Full article
Translational genomics in agriculture: Some examples in grain legumes
Varshney RK, Kudapa H, Pazhamala L, Chitikineni A, Thudi M, Bohra A, Gaur PM, Janila P, Fikre A, Kimurto P and Ellis N (2015). Translational genomics in agriculture: Some examples in grain legumes. Critical Reviews in Plant Sciences 34(1–3):169–194 (DOI: 10.1080/07352689.2014.897909). First published online in October 2014.
Recent advances in genomics and associated disciplines like bioinformatics have made it possible to develop genomic resources, such as large-scale sequence data for any crop species. While these datasets have been proven very useful for the understanding of genome architecture and dynamics as well as facilitating the discovery of genes, an obligation for, and challenge to the scientific community is to translate genome information to develop products, i.e. superior lines for trait(s) of interest. We call this approach, “translational genomics in agriculture” (TGA). TGA is currently in practice for cereal crops, such as maize (Zea mays) and rice (Oryza sativa), mainly in developed countries and by the private sector; progress has been slow for legume crops. Grown globally on 62.8 million ha with a production of 53.2 million tons and a value of nearly 24.2 billion dollars, the majority of these legumes have low crop productivity (<1 ton/ hectare) and are in the developing countries of sub Saharan Africa, Asia and South America. Interestingly, the last five years have seen enormous progress in genomics for these legume crops. Therefore, it is time to implement TGA in legume crops in order to enhance crop productivity and to ensure food security in developing countries. Prospects, as well as some success stories of TGA, in addition to advances in genomics, trait mapping and gene expression analysis are discussed for five leading legume crops, chickpea (Cicer arietinum), common bean (Phaseolus vulgaris), groundnut (Arachis hypogaea), pigeonpea (Cajanus cajan) and soybean (Glycine max). Some efforts have also been outlined to initiate/ accelerate TGA in three additional legume crops namely faba bean (Vicia faba), lentil (Lens culinaris) and pea (Pisum sativum).
Varshney RK, Kudapa H, Pazhamala L, Chitikineni A, Thudi M, Bohra A, Gaur PM, Janila P, Fikre A, Kimurto P and Ellis N (2015). Translational genomics in agriculture: Some examples in grain legumes. Critical Reviews in Plant Sciences 34(1–3):169–194 (DOI: 10.1080/07352689.2014.897909). First published online in October 2014.
Recent advances in genomics and associated disciplines like bioinformatics have made it possible to develop genomic resources, such as large-scale sequence data for any crop species. While these datasets have been proven very useful for the understanding of genome architecture and dynamics as well as facilitating the discovery of genes, an obligation for, and challenge to the scientific community is to translate genome information to develop products, i.e. superior lines for trait(s) of interest. We call this approach, “translational genomics in agriculture” (TGA). TGA is currently in practice for cereal crops, such as maize (Zea mays) and rice (Oryza sativa), mainly in developed countries and by the private sector; progress has been slow for legume crops. Grown globally on 62.8 million ha with a production of 53.2 million tons and a value of nearly 24.2 billion dollars, the majority of these legumes have low crop productivity (<1 ton/ hectare) and are in the developing countries of sub Saharan Africa, Asia and South America. Interestingly, the last five years have seen enormous progress in genomics for these legume crops. Therefore, it is time to implement TGA in legume crops in order to enhance crop productivity and to ensure food security in developing countries. Prospects, as well as some success stories of TGA, in addition to advances in genomics, trait mapping and gene expression analysis are discussed for five leading legume crops, chickpea (Cicer arietinum), common bean (Phaseolus vulgaris), groundnut (Arachis hypogaea), pigeonpea (Cajanus cajan) and soybean (Glycine max). Some efforts have also been outlined to initiate/ accelerate TGA in three additional legume crops namely faba bean (Vicia faba), lentil (Lens culinaris) and pea (Pisum sativum).
QTL associated with lateral root plasticity in response to soil moisture fluctuation stress in rice
Niones JM, Inukai Y, Suralta RR and Yamauchi A (2015). QTL associated with lateral root plasticity in response to soil moisture fluctuation stress in rice. Plant and Soil Published online: 19 February 2015 (DOI: 10.1007/s11104-015-2404-x). (G3008.06)
Abstract: Background Lateral root (LR) plasticity is a key trait that plays a significant role in plant adaptation to fluctuating soil moisture stressed environments. We previously had demonstrated that promoted LR production (LR plasticity) contributed to the maintenance in shoot dry matter production and grain yield under soil moisture fluctuation (SMF) stress.
Aim To identify quantitative trait loci (QTLs) associated with LR plasticity under SMF condition and their contributions to shoot dry matter production.
Methods F2 lines derived from Nipponbare x chromosome segment substituted line number 47 (Nipponbare/Kasalath) backcrosses were used to analyze ten substituted chromosome regions with ‘Kasalath’ allele that are associated with root plasticity under SMF stress.
Results We mapped two closely linked QTLs on chromosome 12 region namely qTLRN-12 at seedling stage and qLLRN-12 at vegetative stage. Under SMF conditions, qTLRN-12 found at the flanking markers between TG154 and RM247 is responsible for the plasticity in total LR number while qLLRN-12 detected at the flanking markers between RM6296 and TG156 is associated with plasticity in L-type LR production. Kasalath genome contributed the corresponding alleles for increasing the mentioned root traits that resulted in a significant increase in shoot dry matter production under SMF stress.
Conclusion We identified two QTLs associated with LR plasticity on chromosome 12 which significantly contributed to the greater root system development and maintenance of total dry matter production under SMF stress.
Niones JM, Inukai Y, Suralta RR and Yamauchi A (2015). QTL associated with lateral root plasticity in response to soil moisture fluctuation stress in rice. Plant and Soil Published online: 19 February 2015 (DOI: 10.1007/s11104-015-2404-x). (G3008.06)
Abstract: Background Lateral root (LR) plasticity is a key trait that plays a significant role in plant adaptation to fluctuating soil moisture stressed environments. We previously had demonstrated that promoted LR production (LR plasticity) contributed to the maintenance in shoot dry matter production and grain yield under soil moisture fluctuation (SMF) stress.
Aim To identify quantitative trait loci (QTLs) associated with LR plasticity under SMF condition and their contributions to shoot dry matter production.
Methods F2 lines derived from Nipponbare x chromosome segment substituted line number 47 (Nipponbare/Kasalath) backcrosses were used to analyze ten substituted chromosome regions with ‘Kasalath’ allele that are associated with root plasticity under SMF stress.
Results We mapped two closely linked QTLs on chromosome 12 region namely qTLRN-12 at seedling stage and qLLRN-12 at vegetative stage. Under SMF conditions, qTLRN-12 found at the flanking markers between TG154 and RM247 is responsible for the plasticity in total LR number while qLLRN-12 detected at the flanking markers between RM6296 and TG156 is associated with plasticity in L-type LR production. Kasalath genome contributed the corresponding alleles for increasing the mentioned root traits that resulted in a significant increase in shoot dry matter production under SMF stress.
Conclusion We identified two QTLs associated with LR plasticity on chromosome 12 which significantly contributed to the greater root system development and maintenance of total dry matter production under SMF stress.
QTL IciMapping: Integrated software for genetic linkage map construction and quantitative trait locus mapping in biparental populations
Meng L, Li H, Zhang L and Wang J (2015). QTL IciMapping: Integrated software for genetic linkage map construction and quantitative trait locus mapping in biparental populations. The Crop Journal (DOI: 10.1016/j.cj.2015.01.001). In press; published online on 23 February 2015. (G8009.10)
Abstract: QTL IciMapping is freely available public software capable of building high-density linkage maps and mapping quantitative trait loci (QTL) in biparental populations. Eight functionalities are integrated in this software package: (1) BIN: binning of redundant markers; (2) MAP: construction of linkage maps in biparental populations; (3) CMP: consensus map construction from multiple linkage maps sharing common markers; (4) SDL: mapping of segregation distortion loci; (5) BIP: mapping of additive, dominant, and digenic epistasis genes; (6) MET: QTL-by-environment interaction analysis; (7) CSL: mapping of additive and digenic epistasis genes with chromosome segment substitution lines; and (8) NAM: QTL mapping in NAM populations. Input files can be arranged in plain text, MS Excel 2003, or MS Excel 2007 formats. Output files have the same prefix name as the input but with different extensions. As examples, there are two output files in BIN, one for summarizing the identified bin groups and deleted markers in each bin, and the other for using the MAP functionality. Eight output files are generated by MAP, including summary of the completed linkage maps, Mendelian ratio test of individual markers, estimates of recombination frequencies, LOD scores, and genetic distances, and the input files for using the BIP, SDL, and MET functionalities. More than 30 output files are generated by BIP, including results at all scanning positions, identified QTL, permutation tests, and detection powers for up to six mapping methods. Three supplementary tools have also been developed to display completed genetic linkage maps, to estimate recombination frequency between two loci, and to perform analysis of variance for multi-environmental trials.
Meng L, Li H, Zhang L and Wang J (2015). QTL IciMapping: Integrated software for genetic linkage map construction and quantitative trait locus mapping in biparental populations. The Crop Journal (DOI: 10.1016/j.cj.2015.01.001). In press; published online on 23 February 2015. (G8009.10)
Abstract: QTL IciMapping is freely available public software capable of building high-density linkage maps and mapping quantitative trait loci (QTL) in biparental populations. Eight functionalities are integrated in this software package: (1) BIN: binning of redundant markers; (2) MAP: construction of linkage maps in biparental populations; (3) CMP: consensus map construction from multiple linkage maps sharing common markers; (4) SDL: mapping of segregation distortion loci; (5) BIP: mapping of additive, dominant, and digenic epistasis genes; (6) MET: QTL-by-environment interaction analysis; (7) CSL: mapping of additive and digenic epistasis genes with chromosome segment substitution lines; and (8) NAM: QTL mapping in NAM populations. Input files can be arranged in plain text, MS Excel 2003, or MS Excel 2007 formats. Output files have the same prefix name as the input but with different extensions. As examples, there are two output files in BIN, one for summarizing the identified bin groups and deleted markers in each bin, and the other for using the MAP functionality. Eight output files are generated by MAP, including summary of the completed linkage maps, Mendelian ratio test of individual markers, estimates of recombination frequencies, LOD scores, and genetic distances, and the input files for using the BIP, SDL, and MET functionalities. More than 30 output files are generated by BIP, including results at all scanning positions, identified QTL, permutation tests, and detection powers for up to six mapping methods. Three supplementary tools have also been developed to display completed genetic linkage maps, to estimate recombination frequency between two loci, and to perform analysis of variance for multi-environmental trials.
Studies on breeding of Yunhan strong gluten wheat varieties for drought resistance and high yield
Li X, Chai Y, Zhao Z, Sun L, Yao J, Bi H and Xi J (2015). Studies on breeding of Yunhan strong gluten wheat varieties for drought resistance and high yield. Chinese Agricultural Science Bulletin 31(12):29–35. Article in Chinese with abstract in English. (G7010.02.01)
Abstract: In order to breeding the high-quality, high-yield, strong gluten and drought-resistant wheat varieties which are suitable for Huanghuai dry land of our country, the research focused on the high yield and high quality breeding goal of strong gluten and high quality foreign germplasm usage. The author used strategies and methods like rational parent combination, adjusting the flowering for inter-breed, assistant selections with high molecular weight glutenin subunit protein molecular marker detections and measuring the quantity and quality of gluten, ecological-adaptation-oriented feature selection identification and ecological selection in multi-points for year. Alternative identification and selections in rain fed and irrigated land, strengthened systematic observation and comprehensive evaluation for better lines, and selections from better lines were conducted. The application of the systematic methods had solved the technical problems of bad adaptability to drought, heat, frost resistance, and maturity of foreign germplasms and hybrids with spring and winter varieties. The research bred a series of strong gluten wheat varieties which were represented by ‘Yunhan20410’,‘Yunhan 618’, achieved the innovation improvement which changed the strong gluten to the strong and stable gluten. They raised 2%-10% production than‘Jinmai 47’and had more drought-resistance and more heat-tolerance. We obtained the combination of high yield and drought resistance with the strong gluten traits.
Li X, Chai Y, Zhao Z, Sun L, Yao J, Bi H and Xi J (2015). Studies on breeding of Yunhan strong gluten wheat varieties for drought resistance and high yield. Chinese Agricultural Science Bulletin 31(12):29–35. Article in Chinese with abstract in English. (G7010.02.01)
Abstract: In order to breeding the high-quality, high-yield, strong gluten and drought-resistant wheat varieties which are suitable for Huanghuai dry land of our country, the research focused on the high yield and high quality breeding goal of strong gluten and high quality foreign germplasm usage. The author used strategies and methods like rational parent combination, adjusting the flowering for inter-breed, assistant selections with high molecular weight glutenin subunit protein molecular marker detections and measuring the quantity and quality of gluten, ecological-adaptation-oriented feature selection identification and ecological selection in multi-points for year. Alternative identification and selections in rain fed and irrigated land, strengthened systematic observation and comprehensive evaluation for better lines, and selections from better lines were conducted. The application of the systematic methods had solved the technical problems of bad adaptability to drought, heat, frost resistance, and maturity of foreign germplasms and hybrids with spring and winter varieties. The research bred a series of strong gluten wheat varieties which were represented by ‘Yunhan20410’,‘Yunhan 618’, achieved the innovation improvement which changed the strong gluten to the strong and stable gluten. They raised 2%-10% production than‘Jinmai 47’and had more drought-resistance and more heat-tolerance. We obtained the combination of high yield and drought resistance with the strong gluten traits.
Transcriptome profiling of wild Arachis from water-limited environments uncovers drought tolerance candidate genes
Brasileiro ACM, Morgante CV, Araujo ACG, Leal-Bertioli SCM, Silva AK, Martins ACQ, Vinson CC, Santos CMR, Bonfim O, Togawa RC, Saraiva MAP, Bertioli DJ and Guimaraes PM (2015). Transcriptome profiling of wild Arachis from water-limited environments uncovers drought tolerance candidate genes. Plant Molecular Biology Reporter Published online: 11 April 2015 (DOI 10.1007/s11105-015-0882-x). (G6010.01)
Abstract: Peanut (Arachis hypogaea L.) is an important legume cultivated mostly in drought-prone areas where its productivity can be limited by water scarcity. The development of more drought-tolerant varieties is, therefore, a priority for peanut breeding programs worldwide. In contrast to cultivated peanut, wild relatives have a broader genetic diversity and constitute a rich source of resistance/tolerance alleles to biotic and abiotic stresses. The present study takes advantage of this diversity to identify drought-responsive genes by analyzing the expression profile of two wild species, Arachis duranensis and Arachis magna (AA and BB genomes, respectively), in response to progressive water deficit in soil. Data analysis from leaves and roots of A. duranensis (454 sequencing) and A. magna (suppression subtractive hybridization (SSH)) stressed and control complementary DNA (cDNA) libraries revealed several differentially expressed genes in silico, and 44 of them were selected for further validation by quantitative RT-PCR (qRT-PCR). This allowed the identification of drought-responsive candidate genes, such as Expansin, Nitrilase, NAC, and bZIP transcription factors, displaying significant levels of differential expression during stress imposition in both species. This is the first report on identification of differentially expressed genes under drought stress and recovery in wild Arachis species. The generated transcriptome data, besides being a valuable resource for gene discovery, will allow the characterization of new alleles and development of molecular markers associated with drought responses in peanut. These together constitute important tools for the peanut breeding program and also contribute to a better comprehension of gene modulation in response to water deficit and rehydration.
Brasileiro ACM, Morgante CV, Araujo ACG, Leal-Bertioli SCM, Silva AK, Martins ACQ, Vinson CC, Santos CMR, Bonfim O, Togawa RC, Saraiva MAP, Bertioli DJ and Guimaraes PM (2015). Transcriptome profiling of wild Arachis from water-limited environments uncovers drought tolerance candidate genes. Plant Molecular Biology Reporter Published online: 11 April 2015 (DOI 10.1007/s11105-015-0882-x). (G6010.01)
Abstract: Peanut (Arachis hypogaea L.) is an important legume cultivated mostly in drought-prone areas where its productivity can be limited by water scarcity. The development of more drought-tolerant varieties is, therefore, a priority for peanut breeding programs worldwide. In contrast to cultivated peanut, wild relatives have a broader genetic diversity and constitute a rich source of resistance/tolerance alleles to biotic and abiotic stresses. The present study takes advantage of this diversity to identify drought-responsive genes by analyzing the expression profile of two wild species, Arachis duranensis and Arachis magna (AA and BB genomes, respectively), in response to progressive water deficit in soil. Data analysis from leaves and roots of A. duranensis (454 sequencing) and A. magna (suppression subtractive hybridization (SSH)) stressed and control complementary DNA (cDNA) libraries revealed several differentially expressed genes in silico, and 44 of them were selected for further validation by quantitative RT-PCR (qRT-PCR). This allowed the identification of drought-responsive candidate genes, such as Expansin, Nitrilase, NAC, and bZIP transcription factors, displaying significant levels of differential expression during stress imposition in both species. This is the first report on identification of differentially expressed genes under drought stress and recovery in wild Arachis species. The generated transcriptome data, besides being a valuable resource for gene discovery, will allow the characterization of new alleles and development of molecular markers associated with drought responses in peanut. These together constitute important tools for the peanut breeding program and also contribute to a better comprehension of gene modulation in response to water deficit and rehydration.
Association of mid-reproductive stage canopy temperature depression with the molecular markers and grain yields of chickpea (Cicer arietinum L.) germplasm under terminal drought
Purushothaman R, Thudi M, Krishnamurthy L, Upadhyaya HD, Kashiwagi J, Gowda CLL and Varshney RK (2015). Association of mid-reproductive stage canopy temperature depression with the molecular markers and grain yields of chickpea (Cicer arietinum L.) germplasm under terminal drought. Field Crops Research 174:1–11 (DOI: 10.1016/j.fcr.2015.01.007). (G4008-12)
Abstract: Canopy temperature depression (CTD) has been used to estimate crop yield and drought tolerance. However, when to measure CTD for the best breeding selection efficacy has seldom been addressed. The objectives of this study were to evaluate CTD as a drought response measure, identify suitable crop stage for measurement and associated molecular markers. CTD was measured using an infrared camera on 59, 62, 69, 73, 76 and 82 days after sowing (DAS) and the grain yield, shoot biomass and harvest index (%). CTD recorded at 62 DAS was positively associated with the grain yield by 40% and shoot biomass by 27% and such association diminished gradually to minimum after 76 DAS. Moreover, CTD at 62 DAS also showed similar positive association with the grain yield recorded in two previous years (r = 0.45***, 0.42***). Genome-wide and candidate gene based association analysis had revealed the presence of nine SSR, 11 DArT and three gene-based markers that varied across the six stages of observation. Two SSR markers were associated with CTD through crop phenology or grain yield while the rest were associated only with CTD for computing marker-trait associations (MTAs). The phenotypic variation explained by the markers was the highest at 62 DAS. These results confirm the importance of continued transpiration and the ability of the roots to supply stored soil water under terminal drought. The selection for grain yield through CTD is done best 15 days after the mean flowering time.
Purushothaman R, Thudi M, Krishnamurthy L, Upadhyaya HD, Kashiwagi J, Gowda CLL and Varshney RK (2015). Association of mid-reproductive stage canopy temperature depression with the molecular markers and grain yields of chickpea (Cicer arietinum L.) germplasm under terminal drought. Field Crops Research 174:1–11 (DOI: 10.1016/j.fcr.2015.01.007). (G4008-12)
Abstract: Canopy temperature depression (CTD) has been used to estimate crop yield and drought tolerance. However, when to measure CTD for the best breeding selection efficacy has seldom been addressed. The objectives of this study were to evaluate CTD as a drought response measure, identify suitable crop stage for measurement and associated molecular markers. CTD was measured using an infrared camera on 59, 62, 69, 73, 76 and 82 days after sowing (DAS) and the grain yield, shoot biomass and harvest index (%). CTD recorded at 62 DAS was positively associated with the grain yield by 40% and shoot biomass by 27% and such association diminished gradually to minimum after 76 DAS. Moreover, CTD at 62 DAS also showed similar positive association with the grain yield recorded in two previous years (r = 0.45***, 0.42***). Genome-wide and candidate gene based association analysis had revealed the presence of nine SSR, 11 DArT and three gene-based markers that varied across the six stages of observation. Two SSR markers were associated with CTD through crop phenology or grain yield while the rest were associated only with CTD for computing marker-trait associations (MTAs). The phenotypic variation explained by the markers was the highest at 62 DAS. These results confirm the importance of continued transpiration and the ability of the roots to supply stored soil water under terminal drought. The selection for grain yield through CTD is done best 15 days after the mean flowering time.
