Confirmation of QTL on porcine chromosomes 1 and 8 influencing leukocyte numbers, haematological parameters and leukocyte function

A genome wide search in European Wild Boar x Swedish Yorkshire (W x Y) inter-cross pigs has earlier identified quantitative trait loci (QTL) for leucocyte number and function on porcine chromosomes 1 and 8 (SSC 1 and 8). To verify the involvement of these chromosomal regions in the regulation of haematocrit (Hem) and haemoglobin (Hb) levels, leucocyte numbers and in vitro leukocyte functions (mitogen induced proliferation and IL-2 production, virus induced interferon-alpha production and neutrophil phagocytosis), animals of different genetic backgrounds were analysed. The animals comprised a back-cross sire family (n=47) of W x Y pigs and six crossbred [Y x Landrace (L)] sire families (n=191). They were genotyped for 16 genetic markers and an interval analysis was performed. On SSC1, a QTL close to S0082 on the q-arm that influenced numbers of white blood cells in L x Y pigs and numbers of band neutrophils and CD8(+) cells in W x Y pigs was identified (P相似文献   

Induction of CD69 activation molecule on human neutrophils by GM-CSF,IFN-gamma,and IFN-alpha

The CD69 glycoprotein is an early activation antigen of T and B lymphocytes but it expression is induced in vitro on cells of most hematopoietic lineages, including neutrophils after stimulation with PMA or fMLP. In this study, we investigated whether CD69 expression on human neutrophils could be modulated by inflammatory or anti-inflammatory cytokines (IL-1beta, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12, IL-18, G-CSF, GM-CSF, TNF-alpha, TGF-beta, IFN-alpha, IFN-gamma). Resting neutrophils from healthy subjects did not express CD69 on the cell surface; moreover, a preformed intracellular pool of CD69 was not evident in these cells. CD69 was barely detectable on these cells after overnight incubation in medium while overnight incubation with GM-CSF, IFN-gamma or IFN-alpha significantly induced CD69 expression on neutrophils with GM-CSF appearing to be the most potent inducer. This induction was dependent on a new protein synthesis as it was significantly inhibited by cycloheximide (about 50% inhibition). CD69 cross-linking on GM-CSF-primed neutrophils sinergized with LPS and increased TNF-alpha production and secretion suggesting a role for CD69-positive neutrophils in the pathogenesis and maintenance of different inflammatory diseases.     

Mapping of quantitative trait loci on porcine chromosome 4

A F₂ population derived from a cross between European Large White and Chinese Meishan pigs was established in order to study the genetic basis of breed differences for growth and fat traits. Chromosome 4 was chosen for initial study as previous work had revealed quantitative trait loci (QTLs) on this chromosome affected growth and fat traits in a Wild Boar × Large White cross. Individuals in the F₂ population were typed for nine markers spanning a region of approximately 124 c m . We found evidence for QTLs affecting growth between weaning and the end of test (additive effect: 43·4 g/day) and fat depth measured in the mid-back position (additive effect: 1·82 mm). There was no evidence of interactions between the QTLs and sex, grandparents or F₁ sires, suggesting that the detected QTLs were fixed for alternative alleles in the Meishan and Large White breeds. Comparison of locations suggests that these QTLs could be the same as those found in the Wild Boar × Large White cross.     

QTLs for grain dry milling properties, composition and vitreousness in maize recombinant inbred lines

Vitreousness and kernel hardness are important properties for maize processing and end-product quality. In order to examine the genetic basis of these traits, a recombinant inbred line population resulting from a cross between a flint line (F-2) and a semident line (Io) was used to search for vitreousness and kernel composition QTLs. Vitreousness was measured by image processing from a kernel section, while NIR spectroscopy was used to estimate starch, protein, cellulose, lipid and semolina yield. In addition, thousand-grain weight and grain weight per ear were measured. The MQTL method was used to map the QTLs for the different traits. An additional program allowed for the detection of interaction QTLs between markers. The total number of main-effect and interaction QTLs was similar. The QTLs were not evenly distributed but tended to cluster. Such clusters, mixing main-effect and interaction QTLs, were observed at six positions : on chromosomes 1, 2, 3, 6, 8 and 9. Two of them, on chromosomes 6 and 9, concerned both QTLs for kernel-weight traits and QTLs for kernel-composition traits (protein and cellulose). Technological-trait QTLs (vitreousness or semolina yield) were located less than 16 cM from a protein-content QTL on chromosome 2, and were co-located with lipid- and starch-content QTLs on chromosome 8. The co-location of a vitreousness and a semolina-yield QTL at the telomeric end of the chromosome 2 (Bin 2.02) is likely to be meaningful since measurement of these related traits, made by completely different methods (NIRS vs image processing), yielded very close QTLs. A similar location was previously reported independently for a kernel-friability QTL. Comparing the map location of the numerous loci for known-function genes it was shown that three zein loci were closely linked to QTLs for vitreousness on chromosome 3, for semolina yield and starch on chromosome 4, and for protein, cellulose and grain weight on chromosome 9. Some other candidate genes linked to starch precursor metabolism were also suggested on chromosomes 6 and 8. Received: 27 April 2000 / Accepted: 3 July 2000     

Identification of QTLs for Yield and Associated Traits in F₂ Population of Rice

Identification of quantitative trait loci (QTLs) controlling yield and yield-related traits in rice was performed in the F₂ mapping population derived from parental rice genotypes DHMAS and K343. A total of 30 QTLs governing nine different traits were identified using the composite interval mapping (CIM) method. Four QTLs were mapped for number of tillers per plant on chromosomes 1 (2 QTLs), 2 and 3; three QTLs for panicle number per plant on chromosomes 1 (2 QTLs) and 3; four QTLs for plant height on chromosomes 2, 4, 5 and 6; one QTL for spikelet density on chromosome 5; four QTLs for spikelet fertility percentage (SFP) on chromosomes 2, 3 and 5 (2 QTLs); two QTLs for grain length on chromosomes 1 and 8; three QTLs for grain width on chromosomes1, 3 and 8; three QTLs for 1000-grain weight (TGW) on chromosomes 1, 4 and 8 and six QTLs for yield per plant (YPP) on chromosomes 2 (3 QTLs), 4, 6 and 8. Most of the QTLs were detected on chromosome 2, so further studies on chromosome 2 could help unlock some new chapters of QTL for this cross of rice variety. Identified QTLs elucidating high phenotypic variance can be used for marker-assisted selection (MAS) breeding. Further, the exploitation of information regarding molecular markers tightly linked to QTLs governing these traits will facilitate future crop improvement strategies in rice.     

Quantitative trait loci for body weight, blood pressure, blood glucose, and serum lipids: linkage analysis with wild rats (Rattus norvegicus).

To study polygenetically inherited human diseases like hypertension, inbred rat strains are usually the preferred models. Because many inbred generations under optimized environmental conditions may have led to the survival of "silent" disease genes, we used a cross between one wild rat and genetically hypertensive SHR rats to analyze quantitative trait loci (QTLs) of blood pressure and related traits. The (Wild x SHR)F1 hybrids were transferred into a pathogen-free environment by wet-hysterectomy and were backcrossed onto SHR to generate first backcross hybrids (BC1). Progeny from one F1 female (n = 72) were phenotypically and genetically characterized to map QTLs. Significant, subsignificant, and suggestive evidence was found for more sex-specific than common linkage of blood pressure and most blood-pressure-related traits. Male- and female-specific regions were determined on different chromosomes for blood pressures (Chrs. 2 and 7 vs 5 and 11), body weight (Chrs. 10 vs 18), and blood glucose (Chr. 17 vs 20). A linkage in both males and females was shown for serum triglycerides on chromosomes 6 and 17, respectively, and blood glucose on chromosome 15. For serum total cholesterol, a significant linkage was found on chromosome 14 only in males. Our findings not only indicate the complex character of quantitative traits per se but also show impressively their dependence on sex, age, and strains in cosegregation analysis.     

Identification of QTLs for eight agronomically important traits using an ultra-high-density map based on SNPs generated from high-throughput sequencing in sorghum under contrasting photoperiods

The productivity of sorghum is mainly determined by agronomically important traits. The genetic bases of these traits have historically been dissected and analysed through quantitative trait locus (QTL) mapping based on linkage maps with low-throughput molecular markers, which is one of the factors that hinder precise and complete information about the numbers and locations of the genes or QTLs controlling the traits. In this study, an ultra-high-density linkage map based on high-quality single nucleotide polymorphisms (SNPs) generated from low-coverage sequences (~0.07 genome sequence) in a sorghum recombinant inbred line (RIL) population was constructed through new sequencing technology. This map consisted of 3418 bin markers and spanned 1591.4 cM of genome size with an average distance of 0.5 cM between adjacent bins. QTL analysis was performed and a total of 57 major QTLs were detected for eight agronomically important traits under two contrasting photoperiods. The phenotypic variation explained by individual QTLs varied from 3.40% to 33.82%. The high accuracy and quality of this map was evidenced by the finding that genes underlying two cloned QTLs, Dw3 for plant height (chromosome 7) and Ma1 for flowering time (chromosome 6), were localized to the correct genomic regions. The close associations between two genomic regions on chromosomes 6 and 7 with multiple traits suggested the existence of pleiotropy or tight linkage. Several major QTLs for heading date, plant height, numbers of nodes, stem diameter, panicle neck length, and flag leaf width were detected consistently under both photoperiods, providing useful information for understanding the genetic mechanisms of the agronomically important traits responsible for the change of photoperiod.     

Genetic Identification of Quantitative Trait Loci for Contents of Mineral Nutrients in Rice Grain

In present study, Fe, Zn, Mn, Cu, Ca, Mg, P and K contents of 85 Introgression linee (ILs) derived from a cross between an elite indica cultivar Teqing and the wild rice (Oryza rufipogon) were measured by inductively coupled argon plasma (ICAP) spectrometry. Substantial variation was observed for all traits and most of the mineral elements were significantly positive correlated or independent except for Fe with Cu. A total of 31 putative quantitative trait loci (QTLs) were detected for these eight mineral elements by single point analysis. Wild rice (O. rufipogon) contributed favorable alleles for most of the QTLs (26 QTLs), and chromosomes 1, 9 and 12 exhibited 14 QTLs (45%) for these traits. One major effect of QTL for zinc content accounted for the largest proportion of phenotypic variation (11%-19%) was detected near the simple sequence repeats marker RM152 on chromosome 8. The co-locations of QTLs for some mineral elements observed in this mapping population suggested the relationship was at a molecular level among these traits and could be helpful for simultaneous improvement of these traits in rice grain by marker assisted selection.     

Molecular dissection of seedling-vigor and associated physiological traits in rice

seedling-vigor is important for crop establishment. There have been reported quantitative trait locus (QTL) analyses on seedling-vigor related morphological traits. However, physiological understanding of these detected QTLs is rather limited. In this study, we employed a recombinant inbred population to detect QTLs for seedling-vigor traits and physiological traits related to seedling-vigor. Germination rate and seedling growth were measured to quantify seedling-vigor. Total amylase activity, !-amylase activity, reducing sugar content, root activity and seed weight were determined. Correlations were observed between the seedling-vigor and physiological traits. QTL analysis reveals that the intervals of RG393-C1087-RZ403 on chromosome 3, C246-RM26-C1447 and R830-R3166-RG360-C734b on chromosome 5, and the interval of Waxy on chromosome 6 are the four main chromosomal regions controlling seedling-vigor. Several QTLs for amylase activities, reducing sugar content and root activity were localized in the similar regions as the QTLs for seedling-vigor. The results suggest that these traits were under the control of pleiotropic and/or closely linked QTLs. The implications of the results in the understanding of the physiological basis of seedling-vigor were discussed.     

Involvement of vitronectin in lipopolysaccaride-induced acute lung injury

Vitronectin is present in large concentrations in serum and participates in regulation of humoral responses, including coagulation, fibrinolysis, and complement activation. Because alterations in coagulation and fibrinolysis are common in acute lung injury, we examined the role of vitronectin in LPS-induced pulmonary inflammation. Vitronectin concentrations were significantly increased in the lungs after LPS administration. Neutrophil numbers and proinflammatory cytokine levels, including IL-1beta, MIP-2, KC, and IL-6, were significantly reduced in bronchoalveolar lavage fluid from vitronectin-deficient (vitronectin(-/-)) mice, as compared with vitronectin(+/+) mice, after LPS exposure. Similarly, LPS induced increases in lung edema, myeloperoxidase-concentrations, and pulmonary proinflammatory cytokine concentrations were significantly lower in vitronectin(-/-) mice. Vitronectin(-/-) neutrophils demonstrated decreased KC-induced chemotaxis as compared with neutrophils from vitronectin(+/+) mice, and incubation of vitronectin(+/+) neutrophils with vitronectin was associated with increased chemotaxis. Vitronectin(-/-) neutrophils consistently produced more TNF-alpha, MIP-2, and IL-1beta after LPS exposure than did vitronectin(+/+) neutrophils and also showed greater degradation of IkappaB-alpha and increased LPS-induced nuclear accumulation of NF-kappaB compared with vitronectin(+/+) neutrophils. These findings provide a novel vitronectin-dependent mechanism contributing to the development of acute lung injury.     

A quantitative genetic study for elucidating the contribution of glutamine synthetase,glutamate dehydrogenase and other nitrogen-related physiological traits to the agronomic performance of common wheat

To better understand the genetic variability for nitrogen use efficiency in winter wheat is a necessity in the frame of the present economic and ecological context. The objective of this work was to investigate the role of the enzymes glutamine synthetase (GS) and glutamate dehydrogenase (GDH), and other nitrogen (N)-related physiological traits in the control of agronomic performance in wheat. A quantitative genetics approach was developed using the Arche × Récital population of doubled haploid lines grown for 3 years in the field. GS and GDH activities, ammonium, amino acid and protein contents were measured at different stages of plant development in different organs after flowering. Significant genotypic effects were observed for all measured physiological and agronomical traits. Heading date was negatively correlated with ammonium, amino acid, protein contents and GS activity in the flag leaf lamina. Grain protein content was positively correlated with both ammonium and amino acid content, and to a lesser extent with soluble protein content and GS activity. A total of 148 quantitative trait loci (QTLs) were detected, 104 QTLs for physiological traits and 44 QTLs for agronomic traits. Twenty-six QTLs were detected for GDH activity spread over 13 chromosomes and 25 QTLs for GS activity spread over 12 chromosomes. We found only a co-localization between a QTL for GS activity and GSe, a structural gene encoding cytosolic GS on chromosome 4B. A coincidence between a QTL for GDH activity and a gene encoding GDH was also found on chromosome 2B. QTL regions combining both physiological and agronomical QTLs were mainly identified on linkage groups 2A, 2B, 2D, 5A, 5B and 5D. This approach allowed us to propose possible functions of physiological traits to explain the variation observed for agronomic traits including yield and its components. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Activation profile of CXCL8-stimulated neutrophils and aging

Neutrophils are pivotal effector cells of innate immunity representing the first line of defense against aggression. They are the first cells to arrive at the site of the aggression, where they can directly eliminate the invading microorganisms. Their activation and recruitment into peripheral tissues is indispensable for host defense. With aging, there are alterations of the receptor by driven functions of human neutrophils as a decrease in the functional changes in signaling elicited by specific receptors, as CXCR1. We investigated the activation of neutrophils from elderly after the cells were cultivated with CXCL8. Although, CXCL8 induced elastase (ELA) secretion, data showed neither myeloperoxidase (MPO) activity nor production of IL-6, IL-10, GM-CSF by neutrophils from elderly compared with young individuals. On the other hand, in the presence of only LPS or LPS associated with CXCL8 neutrophils from elderly individuals, there were significant levels of IL-6, IL-10, GM-CSF but not MPO. These results indicate that neutrophils from elderly do not respond to CXCL8 stimulus, but they are activated by LPS to produce cytokines. However, MPO activity from elderly individuals was not different in the presence or absence of LPS and CXCL8.     

水稻产量库相关穗部性状的遗传分析

收人李源于珍汕97/明恢63的重组系群体中与产量库容有关的10个穗部性状的表现型数据。总体上,每穗颖花数与每穗二次枝梗数、每个二次枝梗上的颖花数、颖花密度有更大的相关性。对所研究的10个性状,两年间共检测到53个QTLs。约43.4%的QTLs能在两年同时检测到。5个染色体区域（第1染色体上G359-RG532和C567-C86-RG236,第2染色体上R712-RM29,第6染色体上P-RG424,第10染色体上C148-RM258）分别对多个穗部性状表现出效应。结果显示相关性状的QTLs大致定位在相似的染色体区域,这表明基因的多效性或紧密连锁是穗部性状间相关的遗传基因。在检测到的大量2位点互作对中,约18.2%在两年都能被检测到。不同性状的共同互作对的比例为8.7%～32.6%。在两年都能检测到2位点组合中,约26.7%的组合同时影响着多个性状,表现出多效效应。结果表明每个性状都由数个QTL、基因型与环境互作、大量的上位性互作所控制。     

Molecular mapping of quantitative trait loci for drought tolerance in maize plants

Drought tolerance is one of the most important but complex traits of crops. We looked for quantitative trait loci (QTLs) that affect drought tolerance in maize. Two maize inbreds and their advanced lines were evaluated for drought-related traits. A genetic linkage map developed using RFLP markers was used to identify QTLs associated with drought-related traits. Twenty-two QTLs were detected, with a minimum of one and a maximum of nine for drought-related traits. A single-QTL was detected for sugar concentration accounting for about 52.2% of the phenotypic variation on chromosome 6. A single-QTL was also identified for each of the traits root density, root dry weight, total biomass, relative water content, and leaf abscisic acid content, on chromosomes 1 and 7, contributing to 24, 0.2, 0.4, 7, and 19% of the phenotypic variance, respectively. Three QTLs were identified for grain yield on chromosomes 1, 5, and 9, explaining 75% of the observed phenotypic variability, whereas four QTLs were detected for osmotic potential on chromosomes 1, 3, and 9, together accounting for 50% of the phenotypic variance. Nine QTLs were detected for leaf surface area on chromosomes 3 and 9, with various degrees of phenotypic variance, ranging from 25.8 to 42.2%. Four major clusters of QTLs were identified on chromosomes 1, 3, 7, and 9. A QTL for yield on chromosome 1 was found co-locating with the QTLs for root traits, total biomass, and osmotic potential in a region of about 15 cM. A cluster of QTLs for leaf surface area were coincident with a QTL for osmotic potential on chromosome 3. The QTLs for leaf area also clustered on chromosome 9, whereas QTLs for leaf abscisic acid content and relative water content coincided on chromosome 7, 10 cM apart. Co-location of QTLs for different traits indicates potential pleiotropism or tight linkage, which may be useful for indirect selection in maize improvement for drought tolerance.     

用RFLP标记剖析水稻穗颈维管束及穗部性状的遗传基础

采用籼、粳亚种间杂种F1(圭630×02428)花药培养获得的DH群体,对水稻穗颈大、小维管束数和倒数第2节间大、小维管束数等4个维管束性状,以及一、二次枝梗数,每穗颖花数3个穗部性状进行QTL分析,共检测到16个QTLs,其中有7个QTLs的加性效应较大,单个QTL的贡献率在20%以上。发现有4个QTLs成簇分布于第1染色体从RZ776到C11的大约35cM的区段上,来源于亲本"圭630"的这一染色体区段对穗颈大维管束、第2节间大维管束、第2节间小维管束和二次枝梗数4个性状的表达均具有增效作用。还讨论了利用分子标记辅助选择聚合增效QTLs、实现穗颈维管束性状遗传改良的策略。     

Identification of Related QTLs at Late Developmental Stage in Rice (Oryza sativa L.) Under Two Nitrogen Levels

QTL underlying related traits at the late developmental stage under two different nitrogen levels were investigated in rice using a population of chromosome segment substitution lines (CSSL) derived from a cross between Teqing and Lemont. A total of 31 QTLs referring 5 traits, that is, plant height (PH), panicle number per plant (PN), chlorophyll content (CC), shoot dry weight (SDW) and grain yield per plant (YD), were detected. Under normal N level, 3 QTLs were detected for each trait, while under low N level, 5,4, 5 and 2 QTLs were detected for PH, PN, CC and SDW respectively. Most of the QTLs were located on chromosome 2, 3, 7, 11 and 12. QTLs controlling different traits or the same trait under different N levels were mapped on the same or adjacent intervals, forming several clusters in rice chromosomes. More than two traits were controlled by QTLs on one of four intervals (RM30-RM439, RM18-RM478, RM309-RM270, and RM235-RM17), suggesting that there were some pleiotropic effects. It was supposed that some QTLs only detected at low N level might be associated with the ability to tolerate the low N stress in rice.     

两种供氮水平下水稻生长后期相关性状的QTL定位

以特青为母本与Lemont杂交,然后用特青为轮回亲本回交,建立特青背景下的染色体片段置换系（CSSL）群体。在正常和低氮条件下分别在生长后期对株高（PH）、单株穗数（PN）、叶绿素含量（CC）、地上部干物重（SDW）和单株籽粒产量（YD）等性状进行了QTL分析,共检测到31个QTL。其中在正常供氮水平下控制PH、PN、CC、SDW和YD的QTL数目均为3个;在低氮水平下检测到5、4、5和2个影响PH、PN、CC和SDW的QTL,在低氮水平下没有检测到控制YD的位点。大部分QTL集中在第2、3、7、11和12染色体上,影响不同性状或在两种供氮水平下影响同一性状的QTL在染色体上成串或成簇分布。其中RM30-RM439、RM18-RM478、RM309-RM270、RM235-RM17等区域同时检测到控制两个以上性状的QTL,表现出明显的一因多效现象。推测仅在低氮水平下检测到的QTL可能跟水稻对低氮胁迫耐性有一定的关联。     

GBS-SNP and SSR based genetic mapping and QTL analysis for drought tolerance in upland cotton

A recombinant inbred line mapping population of intra-species upland cotton was generated from a cross between the drought-tolerant female parent (AS2) and the susceptible male parent (MCU13). A linkage map was constructed deploying 1,116 GBS-based SNPs and public domain-based 782 SSRs spanning a total genetic distance of 28,083.03 cM with an average chromosomal span length of 1,080.12 cM with inter-marker distance of 10.19 cM.A total of 19 quantitative trait loci (QTLs) were identified in nine chromosomes for field drought tolerance traits. Chromosomes 3 and 8 harbored important drought tolerant QTLs for chlorophyll stability index trait while for relative water content trait, three QTLs on chromosome 8 and one QTL each on chromosome 4, 12 were identified. One QTL on each chromosome 8, 5, and 7, and two QTLs on chromosome 15 linking to proline content were identified. For the nitrate reductase activity trait, two QTLs were identified on chromosome 3 and one on each chromosome 8, 13, and 26. To complement our QTL study, a meta-analysis was conducted along with the public domain database and resulted in a consensus map for chromosome 8. Under field drought stress, chromosome 8 harbored a drought tolerance QTL hotspot with two in-house QTLs for chlorophyll stability index (qCSI01, qCSI02) and three public domain QTLs (qLP.FDT_1, qLP.FDT_2, qCC.ST_3). Identified QTL hotspot on chromosome 8 could play a crucial role in exploring abiotic stress-associated genes/alleles for drought trait improvement.Supplementary InformationThe online version contains supplementary material available at 10.1007/s12298-021-01041-y.     

Comparative study of QTLs for agronomic traits of riceOriza sativa L.) between salt stress and nonstress environment

Genotype-by-environment interactions (GxE) are commonly observed for quantitative traits. In the present study, a doubled haploid (DH) population and its genetic linkage map were used to comparatively study QTLs in salt stress and nonstress environments. A total of 24 QTLs were detected for five agronomic traits, which were distributed on all the chromosomes except 9 and 11. Under the salt stress, nine (37.5%) QTLs were detected, including one for 1 000-grain weight (GW), two for heading date (HD), one for plant height (PH), two for grains per panicle (GPP), and three for effective tillers (ET), while in the nonstress environment, 17 QTLs (70.8%) were detected, including five for GW, six for HD, three for PH, two for GPP, and one for ET. Two QTLs (8.3%) were consistently detected in both environments. One was identified on chromosome 4 for HD and the other on Chr.6 for GPP. Furthermore, three regions carrying multiple QTLs were identified on chromosomes 1, 4 and 8 respectively. For example, on chromosome 8, three QTLs for HD, GW and PH, respectively were identified between RG885-GA408 in nonstress environment, but not in the stress environment. The comparative study of QTLs detected in extremely different (salt stress and nonstress) environments revealed that there existed several QTLs for important agronomic traits on chromosome 8 which were affected significantly by salt stress.