共查询到20条相似文献,搜索用时 15 毫秒
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Vinod Kumar Anshuman Singh S. V. Amitha Mithra S. L. Krishnamurthy Swarup K. Parida Sourabh Jain Kapil K. Tiwari Pankaj Kumar Atmakuri R. Rao S. K. Sharma Jitendra P. Khurana Nagendra K. Singh Trilochan Mohapatra 《DNA research》2015,22(2):133-145
Salinity tolerance in rice is highly desirable to sustain production in areas rendered saline due to various reasons. It is a complex quantitative trait having different components, which can be dissected effectively by genome-wide association study (GWAS). Here, we implemented GWAS to identify loci controlling salinity tolerance in rice. A custom-designed array based on 6,000 single nucleotide polymorphisms (SNPs) in as many stress-responsive genes, distributed at an average physical interval of <100 kb on 12 rice chromosomes, was used to genotype 220 rice accessions using Infinium high-throughput assay. Genetic association was analysed with 12 different traits recorded on these accessions under field conditions at reproductive stage. We identified 20 SNPs (loci) significantly associated with Na+/K+ ratio, and 44 SNPs with other traits observed under stress condition. The loci identified for various salinity indices through GWAS explained 5–18% of the phenotypic variance. The region harbouring Saltol, a major quantitative trait loci (QTLs) on chromosome 1 in rice, which is known to control salinity tolerance at seedling stage, was detected as a major association with Na+/K+ ratio measured at reproductive stage in our study. In addition to Saltol, we also found GWAS peaks representing new QTLs on chromosomes 4, 6 and 7. The current association mapping panel contained mostly indica accessions that can serve as source of novel salt tolerance genes and alleles. The gene-based SNP array used in this study was found cost-effective and efficient in unveiling genomic regions/candidate genes regulating salinity stress tolerance in rice. 相似文献
3.
Recent advances in engineering plant tolerance to abiotic stress: achievements and limitations 总被引:41,自引:0,他引:41
Abiotic stresses, especially salinity and drought, are the primary causes of crop loss worldwide. Plant adaptation to environmental stresses is dependent upon the activation of cascades of molecular networks involved in stress perception, signal transduction, and the expression of specific stress-related genes and metabolites. Consequently, engineering genes that protect and maintain the function and structure of cellular components can enhance tolerance to stress. Our limited knowledge of stress-associated metabolism remains a major gap in our understanding; therefore, comprehensive profiling of stress-associated metabolites is most relevant to the successful molecular breeding of stress-tolerant crop plants. Unraveling additional stress-associated gene resources, from both crop plants and highly salt- and drought-tolerant model plants, will enable future molecular dissection of salt-tolerance mechanisms in important crop plants. 相似文献
4.
QTLs and epistasis for aluminum tolerance in rice (Oryza sativa L.) at different seedling stages 总被引:11,自引:0,他引:11
P. Wu C. Y. Liao B. Hu K. K. Yi W. Z. Jin J. J. Ni C. He 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2000,100(8):1295-1303
To investigate the genetic background for aluminum (Al) tolerance in rice, a recombinant inbred (RI) population, derived from
a cross between an Al-sensitive lowland indica rice variety IR1552 and an Al-tolerant upland japonica rice variety Azucena, was used in culture solution. A molecular linkage map, together with 104 amplified fragment length
polymorphism (AFLP) markers and 103 restriction fragment length polymorphism (RFLP) markers, was constructed to map quantitative
trait loci (QTLs) and epistatic loci for Al tolerance based on the segregation for relative root length (RRL) in the population.
RRL was measured after stress for 2 and 4 weeks at a concentration of 1mM of Al3+ and a control with a pH 4.0, respectively. Two QTLs were detected at both the 2nd and the 4th weeks on chromosomes 1 and
12 from unconditional mapping, while the QTL on chromosome 1 was only detected at the 2nd stress week from conditional mapping.
The effect of the QTL on chromosome 12 was increased with an increase of the stress period from 2 to 4 weeks. The QTL on chromosome
1 was expressed only at the earlier stress, but its contribution to tolerance was prolonged during growth. At least one different
QTL was detected at the different stress periods. Mean comparisons between marker genotypic classes indicated that the positive
alleles at the QTLs were from the Al-tolerant upland rice Azucena. An important heterozygous non-allelic interaction on Al
tolerance was found. The results indicated that tolerance in the younger seedlings was predominantly controlled by an additive
effect, while an epistatic effect was more important to the tolerance in older seedlings; additionally the detected QTLs may
be multiple allelic loci for Al tolerance and phosphorus-uptake efficiency, or for Al and Fe2+ tolerance.
Received: 29 July 1999 / Accepted: 13 October 1999 相似文献
5.
应用AFLP与RFLP标记研究水稻磷吸收与利用率的数量性状位点 总被引:4,自引:0,他引:4
To identify genetic factors underlying phosphorus (P) uptake and use efficiency under low-P stress in rice (Oryza sativa L.), 84 selected genotypes (recombinant inbred lines) and their parents (which differed in tolerance for low-P stress) “IR20” and IR55178-3B-9-3, were cultured in liquid medium supplemented with adequate and low P levels in a greenhouse. Plants were sampled after 6 weeks in culture for measurements of plant dry weight, P concentration, P uptake and P use efficiency under both P sufficient and stress conditions. A total of 179 molecular markers, including 26 RFLPs and 153 AFLPs, mapped on all 12 chromosomes of rice based on the 84 selected genotypes were used to detect the quantitative trait loci (QTLs) underlying tolerance for low-P stress. Three QTLs were detected on chromosomes 6, 7 and 12, respectively, for relative plant dry weight (RPDW) and relative P uptake (RPUP). One of the QTLs flanked by RG9 and RG241 on chromosome 12 had a major effect which explained about 50% of the variations in the two parameters across the population. The results coincided with the QTLs for low-P stress based on relative tillering ability from the same population from a cross between Nipponbare and Kasalath under soil condition. The identical major QTL for P uptake and plant growth under low-P stress in both liquid medium and soil strongly suggests that the ability of P uptake mainly controls rice tolerance for low-P stress. 相似文献
6.
Mapping QTLs for Phosphorus-Deficiency Tolerance at Wheat Seedling Stage 总被引:13,自引:0,他引:13
Junying Su Yanmei Xiao Ming Li Quanyou Liu Bin Li Yiping Tong Jizeng Jia Zhensheng Li 《Plant and Soil》2006,281(1-2):25-36
Soil phosphorus (P) deficiency is one of the major limiting factors to crop production throughout the world. It is an important
strategy to breed varieties with improved P-deficiency tolerance for sustainable agriculture. The objective of this study
was to map QTLs for P-deficiency tolerance in wheat, and develop molecular marker assisted selection in breeding wheat with
improved P-deficiency tolerance. A doubled haploid (DH) population, consisting of 92 DH lines (DHLs) derived from P-deficiency
tolerant wheat variety Lovrin 10 and P-deficiency sensitive variety Chinese Spring, was developed for mapping QTLs for P-deficiency
tolerance. A genetic linkage map consisting of 34 linkage groups was constructed using 253 SSR markers. Shoot dry weight (SDW),
tiller number (TN), shoot P uptake (SPU), and shoot P utilization efficiency (PUE) were investigated at seedling stage under
P deficiency (−P) and sufficiency (+P) condition in two pot trials in 2002 and 2003, respectively. All traits segregated continuously
in the population under either −P or +P condition. Significant positive correlations were found in between TN, SDW and SPU,
whereas significant negative correlations were observed between PUE and SPU and between PUE and TN. Twenty and 19 QTLs were
detected under −P and +P condition, respectively. The 39 QTLs were distributed on 21 chromosomal regions. There were three
clusters of QTLs, which were associated with Xgwm25l (on chromosomes 4B), Xgwm271.2 (on chromosome 5A), and Xgwm121 (on chromosome 5D), respectively. Compared to the DHLs with all Chinese Spring alleles at the three loci, those with all
Lovrin 10 alleles had, on average, much higher SPU, SDW and TN under −P condition in both trials, suggesting the importance
of the three loci in controlling P-deficiency tolerance. It was interesting to find that two of the above three loci were
closely linked with vernalization requirement genes VRN-A1 (on chromosome 5A) and VRN-D1 (on chromosome 5D). Potential implication of the linkage between P-deficiency tolerance and VRN genes was discussed. 相似文献
7.
Xu XF Mei HW Luo LJ Cheng XN Li ZK 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2002,104(2-3):248-253
Quantitative trait loci (QTLs), conferring quantitative resistance to rice brown planthopper (BPH), were investigated using
160 F11 recombinant inbred lines (RILs) from the Lemont/Teqing cross, a complete RFLP map, and replicated phenotyping of seedbox
inoculation. The paternal indica parent, Teqing, was more-resistant to BPH than the maternal japonica parent, Lemont. The
RILs showed transgressive segregation for resistance to BPH. Seven main-effect QTLs and many epistatic QTL pairs were identified
and mapped on the 12 rice chromosomes. Collectively, the main-effect and epistatic QTLs accounted for over 70% of the total
variation in damage scores. Teqing has the resistance allele at four main-effect QTLs, and the Lemont allele resulted in resistance
at the other three. Of the main-effect QTLs identified, QBphr5b was mapped to the vicinity of gl1, a major gene controlling leaf and stem pubescence. The Teqing allele controlling leaf and stem pubescence was associated
with resistance, while the Lemont allele for glabrous stem and leaves was associated with susceptibility, indicating that
this gene may have contributed to resistance through antixenosis. Similar to the reported BPH resistance genes, the other
six detected main-effect QTLs were all mapped to regions where major disease resistance genes locate, suggesting they might
have contributed either to antibiosis or tolerance. Our results indicated that marker-aided pyramiding of major resistance
genes and QTLs should provide effective and stable control over this devastating pest.
Received: 10 December 2000 / Accepted: 7 May 2001 相似文献
8.
Recent Advances in Genetics of Salt Tolerance in Tomato 总被引:13,自引:0,他引:13
Salinity is an important environmental constraint to crop productivity in arid and semi-arid regions of the world. Most crop plants, including tomato, Lycopersicon esculentum Mill., are sensitive to salinity throughout the ontogeny of the plant. Despite considerable research on salinity in plants, there are only a few instances where salt-tolerant cultivars have been developed. This is due in part to the complexity of the trait. A plant's response to salt stress is modulated by many physiological and agronomical characteristics, which may be controlled by the actions of several to many genes whose expressions are influenced by various environmental factors. In addition, salinity tolerance is a developmentally regulated, stage-specific phenomenon; tolerance at one stage of plant development is often not correlated with tolerance at other stages. Specific ontogenic stages should be evaluated separately for the assessment of tolerance and the identification, characterization, and utilization of useful genetic components. In tomato, genetic resources for salt tolerance have been identified largely within the related wild species, and considerable efforts have been made to characterize the genetic controls of tolerance at various developmental stages. For example, the inheritance of several tolerance-related traits has been determined and quantitative trait loci (QTLs) associated with tolerance at individual developmental stages have been identified and characterized. It has been determined that at each stage salt tolerance is largely controlled by a few QTLs with major effects and several QTLs with smaller effects. Different QTLs have been identified at different developmental stages, suggesting the absence of genetic relationships among stages in tolerance to salinity. Furthermore, it has been determined that in addition to QTLs which are population specific, several QTLs for salt tolerance are conserved across populations and species. Research is currently underway to develop tomatoes with improved salt tolerance throughout the ontogeny of the plant by pyramiding QTLs through marker-assisted selection (MAS). Transgenic approaches also have been employed to gain a better understanding of the genetics of salt tolerance and to develop tomatoes with improved tolerance. For example, transgenic tomatoes with overexpression of a single-gene-controlled vacuolar Na+/H+ antiport protein, transferred from Arabidopsis thaliana, have exhibited a high level of salt tolerance under greenhouse conditions. Although transgenic plants are yet to be examined for field salt tolerance and salt-tolerant tomatoes are yet to be developed by MAS, the recent genetic advances suggest a good prospect for developing commercial cultivars of tomato with enhanced salt tolerance in near future. 相似文献
9.
Soumaya Arraouadi Fabien Chardon Thierry Huguet Mohamed Elarbi Aouani Mounawer Badri 《Acta Physiologiae Plantarum》2011,33(3):917-926
To understand the complex inheritance of tolerance to salt stress in Medicago truncatula, quantitative trait loci (QTLs) analysis was performed using a set of recombinant inbred lines (RILs) derived from a cross
between the tolerant line Jemalong A17 and susceptible line F83005.5. The RILs and parental lines were grown in individual
pots filled with sterilized sand in a greenhouse under 0 and 50 mM NaCl. Plants were harvested after a period of 60 days.
Fourteen quantitative traits related to aerial and root growths were measured. Broad-sense heritability of measured traits
ranged from 0.21 to 0.83 and from 0.05 to 0.62 in control and in salt-stressed conditions, respectively. Established correlations
between measured traits are dependent on treatment effect. We identified and mapped 10 QTLs in control conditions and 19 in
salt stress. No major QTL was identified indicating that tolerance to salt stress is governed by several genes with low effects.
The QTLs detected under control and under salt-stressed conditions almost did not share the same map locations suggesting
that the loci that are not stable across treatments reflect adaptation to this constraint. The maximum of QTLs was observed
on the chromosome 8. The usefulness of these QTLs, identified in greenhouse conditions, for marker-assisted selection should
therefore be evaluated under field conditions, and validated in other genetic backgrounds. 相似文献
10.
Quantitative Trait Loci Mapping for ChlorophyⅡ Fluorescence and Associated Traits in Wheat ( Triticum aestivum) 总被引:10,自引:0,他引:10
De-Long Yang Rui-Lian Jing Xiao-Ping Chang Wei Li 《植物学报(英文版)》2007,49(5):646-654
Parameters of chlorophyll fluorescence kinetics (PCFKs) under drought stress condition are generally used to characterize instincts for dehydration tolerance in wheat (Triticum aestivum L.). Therefore, it is important to map quantitative trait loci (QTLs) for PCFKs in wheat genetic improvement for drought tolerance. A doubled haploid (DH) population with 150 lines, derived from a cross between two common wheat varieties, Hanxuan 10 and Lumai 14, was used to analyze the correlation between PCFKs and chlorophyll content (CHIC) and to map QTLs at the grainfilling stage under conditions of both rainfed (drought stress, DS) and well-watered (WW), respectively. QTLs for these traits were detected by QTLMapper version 1.0 based on the composite Interval mapping method of the mixed-linear model. The results showed a very significant positive correlation between Fv, Fm, Fv/Fm and Fv/Fo. The correlation coefficients were generally higher under WW than under DS. Also, there was a significant or a highly significant positive correlation between Fv, Fm, Fv/Fm, Fv/Fo and CHIC. The correlation coefficients were higher in the DS group than the WW group. A total of 14 additive QTLs (nine QTLs detected under DS and five QTLs under WW) and 25 pairs of eplstatlc QTLs (15 pairs detected under DS and 10 pairs under WW) for PCFKs were mapped on chromosomes 6A, 7A, 1B, 3B, 4D and 7D. The contributions of additive QTLs for PCFKs to phenotype variation were from 8.40% to 72.72%. Four additive QTLs (two QTLs detected under DS and WW apiece) controlling Chic were mapped on chromosomes 1A, 5A and 7A. The contributions of these QTLs for ChIC to phenotype variation were from 7.27% to 11.68%. Several QTL clusters were detected on chromosomes 1B, 7A and 7D, but no shared chromosomal regions for them were identified under different water regimes, indicating that these QTLs performed different expression patterns under rainfed and well-watered conditions. 相似文献
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12.
Quantitative trait loci (QTLs) for drought tolerance (DT) can be readily identified in available databases and in this paper, these QTLs were summarized in the form of a consensus map. An in silico strategy was then deployed to mine for candidate genes associated with DT QTLs using rice dbEST and rice genome databases. DT QTLs on rice chromosomes 1, 2, 4, 8, and 9 were selected to test the method. The result showed candidate genes associated with DT could be readily identified. 相似文献
13.
Conditional and unconditional QTL mapping of drought-tolerance-related traits of wheat seedling using two related RIL populations 总被引:1,自引:0,他引:1
HONG ZHANG FA CUI LIN WANG JUN LI ANMING DING CHUNHUA ZHAO YINGUANG BAO QIUPING YANG HONGGANG WANG 《Journal of genetics》2013,92(2):213-231
For discovering the quantitative trait loci (QTLs) contributing to early seedling growth and drought tolerance during germination, conditional and unconditional analyses of 12 traits of wheat seedlings: coleoptile length, seedling height, longest root length, root number, seedling fresh weight, stem and leaves fresh weight, root fresh weight, seedling dry weight, stem and leaves dry weight, root dry weight, root to shoot fresh weight ratio, root-to-shoot dry weight ratio, were conducted under two water conditions using two F8:9 recombinant inbred line (RIL) populations. The results of unconditional analysis are as follows: 88 QTLs accounting for 3.33–77.01% of the phenotypic variations were detected on chromosomes 1A, 1B, 1D, 2A, 2B, 2D, 3A, 3B, 4A, 4B, 4D, 5A, 5B, 5D, 6A, 6B, 6D, 7A, 7B and 7D. Among these QTLs, 19 were main-effect QTLs with a contribution rate greater than 10%. The results of the conditional QTL analysis of 12 traits under osmotic stress on normal water conditions were as follows: altogether 22 QTLs concerned with drought tolerance were detected on chromosomes 1B, 2A, 2B, 3B, 4A, 5D, 6A, 6D, 7B, and 7D. Of these QTLs, six were main-effect QTLs. These 22 QTLs were all special loci directly concerned with drought tolerance and most of them could not be detected by unconditional analysis. The finding of these QTLs has an important significance for fine-mapping technique, map-based cloning, and molecular marker-assisted selection of early seedling traits, such as growth and drought tolerance. 相似文献
14.
M. Matos V. Pérez-Flores M. V. Camacho B. Pernaute O. Pinto-Carnide C. Benito 《Molecular breeding : new strategies in plant improvement》2007,20(2):103-115
Aluminium toxicity is a major problem for crop production on acid soils. Rye (Secale cereale L.) has one of the most efficient group of genes for aluminium tolerance, at least, four independent and dominant loci, Alt1, Alt2, Alt3 and Alt4, located on chromosome arms 6RS, 3RS, 4RL and 7RS, have been described. The increasing availability of expressed sequence
tags in rye and related cereals provides a valuable resource of non-anonymous DNA molecular markers. In order to obtain simple
sequence repeat (SSR) markers related with Al tolerance more than 1,199 public accessible rye cDNA sequences from Al-stressed
roots were exploited as a resource for SSR markers development. From a total of 21 S. cereale microsatellite (SCM) loci analysed, 12 were located on chromosomes 1R, 2R, 3R, 4R and 5R, using wheat–rye addition lines
or mapped using a F2 population segregating for Al tolerance. Seven SCM loci were included in a rye map with other SCIM and RAPD markers. Moreover,
14 SCM loci could be associated to proteins with known or unknown function. The possible implications of these sequences in
aluminium tolerance mechanisms are discussed. 相似文献
15.
Detection and analysis of QTLs for resistance to the brown planthopper, Nilaparvata lugens, in a doubled-haploid rice population 总被引:5,自引:0,他引:5
S. N. Alam M. B. Cohen 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,97(8):1370-1379
We used a mapping population of 131 doubled-haploid lines, produced from a cross between an improved indica rice variety (IR64) and a traditional japonica variety (Azucena), to detect quantitative trait loci (QTLs) for resistance to the brown planthopper (BPH), Nilaparvata lugens. We evaluated the parents and mapping population with six tests that measure varying combinations of the three basic mechanisms
of insect host plant resistance, i.e., antixenosis, antibiosis, and tolerance. To factor-out the effect of the major resistance
gene Bph1 from IR64, the screening was done with two BPH populations from Luzon Island, The Philippines, that are almost completely
adapted to this gene. A total of seven QTLs associated with resistance were identified, located on 6 of the 12 rice chromosomes.
Individual QTLs accounted for between 5.1 and 16.6% of the phenotypic variance. Two QTLs were predominantly associated with
a single resistance mechanism: one with antixenosis and one with tolerance. Most of the QTLs were derived from IR64, which
has been shown to have a relatively durable level of moderate resistance under field conditions. The results of this study
should be useful in transferring this resistance to additional rice varieties.
Received: 10 May 1998 / Accepted: 4 June 1998 相似文献
16.
Identification of two closely linked quantitative trait loci for cold tolerance on chromosome 4 of rice and their association with anther length 总被引:20,自引:0,他引:20
K. Saito K. Miura K. Nagano Y. Hayano-Saito H. Araki A. Kato 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2001,103(6-7):862-868
Norin-PL8 is a cold-tolerant variety of rice (Oryza sativa L.) that was developed by introgressing chromosomal segments from a cold-tolerant javanica variety, Silewah. We previously detected quantitative trait loci (QTLs) for cold tolerance of Norin-PL8 in the introgressions
on chromosomes 3 and 4. We provide fine mapping of the QTLs on chromosome 4 and the association between the QTLs and anther
length, which has been reported to be a major component of cold tolerance. Interval mapping using a segregating population
derived from an advanced backcross progeny indicated that a QTL for cold tolerance is probably located from the center to
the proximal end of the introgression. For fine mapping, we developed a set of near-isogenic lines (NILs) from recombinants
in the segregating population. Comparison of cold tolerance between the NILs indicated that either the proximal end or the
center of the introgression is necessary for cold tolerance. From these results, we concluded that there are at least two
QTLs for cold tolerance, tentatively designated as Ctb-1 and Ctb-2, in the introgression on chromosome 4. The map distance between Ctb-1 and Ctb-2 is estimated to be 4.7–17.2 cM. In order to investigate the mechanism underlying cold tolerance by the QTLs, we compared
anther lengths of the NILs. The results indicate that both Ctb-1 and Ctb-2 are associated with anther length.
Received: 17 July 2000 / Accepted: 1 February 2001 相似文献
17.
Quantitative trait loci influencing drought tolerance in grain sorghum (Sorghum bicolor L. Moench) 总被引:7,自引:0,他引:7
H. Kebede P. K. Subudhi D. T. Rosenow H. T. Nguyen 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2001,103(2-3):266-276
Drought is a major constraint in sorghum production worldwide. Drought-stress in sorghum has been characterized at both pre-flowering
and post-flowering stages resulting in a drastic reduction in grain yield. In the case of post-flowering drought stress, lodging
further aggravates the problem resulting in total loss of crop yield in mechanized agriculture. The present study was conducted
to identify quantitative trait loci (QTLs) controlling post-flowering drought tolerance (stay green), pre-flowering drought
tolerance and lodging tolerance in sorghum using an F7 recombinant inbred line (RIL) population derived from the cross SC56×Tx7000. The RIL lines, along with parents, were evaluated
for the above traits in multiple environments. With the help of a restriction fragment length polymorphism (RFLP) map, which
spans 1,355 cM and consists of 144 loci, nine QTLs, located over seven linkage groups were detected for stay green in several
environments using the method of composite interval mapping. Comparison of the QTL locations with the published results indicated
that three QTLs located on linkage groups A, G and J were consistent. This is considered significant since the stay green
line SC56 used in our investigation is from a different source compared to B35 that was used in all the earlier investigations.
Comparative mapping has shown that two stay green QTLs identified in this study corresponded to stay green QTL regions in
maize. These genomic regions were also reported to be congruent with other drought-related agronomic and physiological traits
in maize and rice, suggesting that these syntenic regions might be hosting a cluster of genes with pleiotropic effects implicated
in several drought tolerance mechanisms in these grass species. In addition, three and four major QTLs responsible for lodging
tolerance and pre-flowering drought tolerance, respectively, were detected. This investigation clearly revealed the important
and consistent stay green QTLs in a different stay green source that can logically be targeted for positional cloning. The
identification of QTLs and markers for pre-flowering drought tolerance and lodging tolerance will help plant breeders in manipulating
and pyramiding those traits along with stay green to improve drought tolerance in sorghum.
Received: 2 June 2000 / Accepted: 15 November 2000 相似文献
18.
Qing-Hong Zhou Dong-Hui Fu Annaliese S. Mason Yong-Jun Zeng Chao-Xian Zhao Ying-Jin Huang 《Molecular breeding : new strategies in plant improvement》2014,33(4):881-894
Mapping quantitative trait loci (QTLs) is a foundation for molecular marker-assisted selection and map-based gene cloning. During the past decade, numerous QTLs for seed yield (SY) and yield-related traits in Brassica napus L. have been identified. However, integration of these results in order to compare QTLs from different mapping populations has not been undertaken, due to the lack of common molecular markers between studies. Using previously reported Brassica rapa and Brassica oleracea genome sequences, we carried out in silico integration of 1,960 QTLs associated with 13 SY and yield-related traits from 15 B. napus mapping experiments over the last decade. A total of 736 SY and yield-related QTLs were mapped onto 283 loci in the A and C genomes of B. napus. These QTLs were unevenly distributed across the 19 B. napus chromosomes, with the most on chromosome A3 and the least on chromosome C6. Our integrated QTL map identified 142 loci where the conserved QTLs were detected and 25 multifunctional loci, mostly for the traits of flowering time (FT), plant height, 1,000-seed weight, maturity time and SY. These conserved QTLs and multifunctional loci may result from pleiotropism or clustered genes. At the same time, a total of 146 genes underlying the QTLs for FT and other yield-related traits were identified by comparative mapping with the Arabidopsis genome. These results facilitate the retrieval of B. napus SY and yield-related QTLs for research communities, increase the density of targeted QTL-linked markers, validate the existence of QTLs across different populations, and advance the fine mapping of genes. 相似文献
19.
Narasimhamoorthy B Bouton JH Olsen KM Sledge MK 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2007,114(5):901-913
Aluminum (Al) toxicity in acid soils is a major limitation to the production of alfalfa (Medicago sativa subsp. sativa L.) in the USA. Developing Al-tolerant alfalfa cultivars is one approach to overcome this constraint. Accessions of wild
diploid alfalfa (M. sativa subsp. coerulea) have been found to be a source of useful genes for Al tolerance. Previously, two genomic regions associated with Al tolerance
were identified in this diploid species using restriction fragment length polymorphism (RFLP) markers and single marker analysis.
This study was conducted to identify additional Al-tolerance quantitative trait loci (QTLs); to identify simple sequence repeat
(SSR) markers that flank the previously identified QTLs; to map candidate genes associated with Al tolerance from other plant
species; and to test for co-localization with mapped QTLs. A genetic linkage map was constructed using EST-SSR markers in
a population of 130 BC1F1 plants derived from the cross between Al-sensitive and Al-tolerant genotypes. Three putative QTLs on linkage groups LG I,
LG II and LG III, explaining 38, 16 and 27% of the phenotypic variation, respectively, were identified. Six candidate gene
markers designed from Medicago truncatula ESTs that showed homology to known Al-tolerance genes identified in other plant species were placed on the QTL map. A marker
designed from a candidate gene involved in malic acid release mapped near a marginally significant QTL (LOD 2.83) on LG I.
The SSR markers flanking these QTLs will be useful for transferring them to cultivated alfalfa via marker-assisted selection
and for pyramiding Al tolerance QTLs. 相似文献
20.
Dias PM Brunel-Muguet S Dürr C Huguet T Demilly D Wagner MH Teulat-Merah B 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2011,122(2):429-444
Enhancing the knowledge on the genetic basis of germination and heterotrophic growth at extreme temperatures is of major importance
for improving crop establishment. A quantitative trait loci (QTL) analysis was carried out at sub- and supra-optimal temperatures
at these early stages in the model Legume Medicago truncatula. On the basis of an ecophysiological model framework, two populations of recombinant inbred lines were chosen for the contrasting
behaviours of parental lines: LR5 at sub-optimal temperatures (5 or 10°C) and LR4 at a supra-optimal temperature (20°C). Seed
masses were measured in all lines. For LR5, germination rates and hypocotyl growth were measured by hand, whereas for LR4,
imbibition and germination rates as well as early embryonic axis growth were measured using an automated image capture and
analysis device. QTLs were found for all traits. The phenotyping framework we defined for measuring variables, distinguished
stages and enabled identification of distinct QTLs for seed mass (chromosomes 1, 5, 7 and 8), imbibition (chromosome 4), germination
(chromosomes 3, 5, 7 and 8) and heterotrophic growth (chromosomes 1, 2, 3 and 8). The three QTL identified for hypocotyl length
at sub-optimal temperature explained the largest part of the phenotypic variation (60% together). One digenic interaction
was found for hypocotyl width at sub-optimal temperature and the loci involved were linked to additive QTLs for hypocotyl
elongation at low temperature. Together with working on a model plant, this approach facilitated the identification of genes
specific to each stage that could provide reliable markers for assisting selection and improving crop establishment. With
this aim in view, an initial set of putative candidate genes was identified in the light of the role of abscissic acid/gibberellin
balance in regulating germination at high temperatures (e.g. ABI4, ABI5), the molecular cascade in response to cold stress (e.g. CBF1, ICE1) and hypotheses on changes in cell elongation (e.g. GASA1, AtEXPA11) with changes in temperatures based on studies at the whole plant scale. 相似文献