QTL mapping of resistance to Sclerotinia midstalk rot in RIL of sunflower population NDBLOSsel × CM625

Midstalk rot caused by Sclerotinia sclerotiorum is an important disease of sunflower in its main areas of cultivation. The objectives of this study were to (1) verify quantitative trait loci (QTL) for midstalk-rot resistance found in F₃ families of the NDBLOS_sel × CM625 population in recombinant inbred lines (RIL) derived from the same cross; (2) re-estimate their position and genetic effects; (3) draw inferences about the predictive quality of QTL for midstalk-rot resistance identified in the F₃ families as compared to those in the RIL. Phenotypic data for three resistance (leaf lesion, stem lesion, and speed of fungal growth) and two morphological traits (leaf length and leaf length with petiole) were obtained from 317 RIL following artificial infection in field experiments across two environments. For genotyping the 248 RIL, we selected 41 simple sequence repeat (SSR) markers based on their association with QTL for Sclerotinia midstalk-rot resistance in an earlier study. The resistance traits showed intermediate to high heritabilities and were significantly correlated with each other Genotypic correlations between F₃ families and the RIL were highly significant and ranged between 0.50 for leaf length and 0.64 for stem lesion. For stem lesion, two genomic regions on linkage group (LG) 8 and LG16 explaining 26.5% of the genotypic variance for Sclerotinia midstalk-rot resistance were consistent across generations. For this trait, the genotypic correlation between the observed performance and its prediction based on QTL positions and effects in F₃ families was surprisingly high The genetic effects and predictive quality of these two QTL are promising for application in marker-assisted selection to Sclerotinia midstalk-rot resistance.     

QTL mapping of powdery mildew resistance in WI 2757 cucumber (Cucumis sativus L.)

Powdery mildew (PM) is a very important disease of cucumber (Cucumis sativus L.). Resistant cultivars have been deployed in production for a long time, but the genetic mechanisms of PM resistance in cucumber are not well understood. A 3-year QTL mapping study of PM resistance was conducted with 132 F_2:3 families derived from two cucumber inbred lines WI 2757 (resistant) and True Lemon (susceptible). A genetic map covering 610.4 cM in seven linkage groups was developed with 240 SSR marker loci. Multiple QTL mapping analysis of molecular marker data and disease index of the hypocotyl, cotyledon and true leaf for responses to PM inoculation identified six genomic regions in four chromosomes harboring QTL for PM resistance in WI 2757. Among the six QTL, pm1.1 and pm1.2 in chromosome 1 conferred leaf resistance. Minor QTL pm3.1 (chromosome 3) and pm4.1 (chromosome 4) contributed to disease susceptibility. The two major QTL, pm5.1 and pm5.2 were located in an interval of ~40 cM in chromosome 5 with each explaining 21.0–74.5 % phenotypic variations. Data presented herein support two recessively inherited, linked major QTL in chromosome 5 plus minor QTL in other chromosomes that control the PM resistance in WI 2757. The QTL pm5.2 for hypocotyl resistance plays the most important role in host resistance. Multiple observations in the same year revealed the importance of scoring time in the detection of PM resistance QTL. Results of this study provided new insights into phenotypic and genetic mechanisms of powdery mildew resistance in cucumber.     

Structural mapping of Kelch13 mutations associated with artemisinin resistance in malaria

Mutations in Plasmodium falciparum gene kelch13 (pfkelch13) are strongly and causally associated with resistance to anti-malarial drug artemisinin, but their effects on PfKelch13 structure and function remain unclear. Utilizing the publicly available three-dimensional structure of PfKech13 (PDB ID: 4yy8), we find that most of the mutations in its propeller domain occur in two spatial clusters. Of these, one cluster is enriched in surface exposed residues which may drive PfKelch13-centered protein interactions, and the second cluster mostly contains residues which are buried and whose mutations may destabilize PfKelch13 structure. The most prevalent resistant mutations C580Y and Y493H are distal from the above two clusters. The C580Y mutation creates sterically unfavourable contacts while Y493H possibly alters the hydrophobic core of the propeller domain. These analyses will facilitate further experimental studies aimed at understanding how mutations in pfkelch13 lead to artemisinin resistance.     

Genetic mapping of QTL for resistance to Fusarium head blight spread (type 2 resistance) in a Triticum dicoccoides × Triticum durum backcross-derived population

Improvement of resistance to Fusarium head blight (FHB) is a continuous challenge for durum wheat breeders, particularly due to the limited genetic variation within this crop species. We accordingly generated a backcross-derived mapping population using the type 2 FHB resistant Triticum dicoccoides line Mt. Gerizim #36 as donor and the modern Austrian T. durum cultivar Helidur as recipient; 103 BC₁F_6:7 lines were phenotyped for type 2 FHB resistance using single-spikelet inoculations and genotyped with 421 DNA markers (SSR and AFLP). QTL mapping revealed two highly significant QTL, mapping to chromosomes 3A and 6B, respectively. For both QTL the T. dicoccoides allele improved type 2 FHB resistance. Recombinant lines with both favorable alleles fixed conferred high resistance to FHB similar to that observed in the T. dicoccoides parent. The results appear directly applicable for durum wheat resistance breeding.     

Detection of Fusarium head blight resistance QTLs using five populations of top-cross progeny derived from two-row × two-row crosses in barley

Fusarium head blight (FHB) resistance was evaluated in five recombinant inbred (RI) populations. The RI populations consisted of top-cross progeny derived from a diallel set of crosses. Each of five two-row barley lines differing in response to FHB were crossed with ‘Harbin 2-row’. FHB severity was scored on an 11-point scale, where resistant = 0 and susceptible = 10, based on the ‘cut-spike test’. Disease data were obtained for each population for 2 or 3 years. Linkage maps comprised of expressed sequence tag (EST) markers were developed for each population and used for quantitative trait locus (QTL) detection. Thirty two QTLs were detected using all data sets (individual populations and years). Thirteen QTLs were detected using averages across years; 10 of these were consistent across the individual year and average data sets. These QTLs clustered at 14 regions, with clusters on all chromosomes. At 11 of these clusters, Harbin 2-row contributed FHB resistance alleles. No QTLs were detected near the row type (vrs1) locus in any of the five RI populations, suggesting that the FHB resistance QTL in this region reported in two-row × six-row crosses may be pleiotropic effect of vrs1. QTL were coincident with the flowering type locus (cly1/Cly2) on chromosome 2H in every population. Some QTL × QTL interactions were significant, but these were smaller than QTL main effects. Considering the pleiotropic effect of spike morphology on FHB resistance, future FHB resistance mapping efforts in barley should focus on cross combinations in which alleles at vrs1 are not segregating. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Tree resistance to Lymantria dispar caterpillars: importance and limitations of foliar tannin composition

The ability of foliar tannins to increase plant resistance to herbivores is potentially determined by the composition of the tannins; hydrolyzable tannins are much more active as prooxidants in the guts of caterpillars than are condensed tannins. By manipulating the tannin compositions of two contrasting tree species, this work examined: (1) whether increased levels of hydrolyzable tannins increase the resistance of red oak (Quercus rubra L.), a tree with low resistance that produces mainly condensed tannins, and (2) whether increased levels of condensed tannins decrease the resistance of sugar maple (Acer saccharum Marsh.), a tree with relatively high resistance that produces high levels of hydrolyzable tannins. As expected, when Lymantria dispar L. caterpillars ingested oak leaves coated with hydrolyzable tannins, levels of hydrolyzable tannin oxidation increased in their midgut contents. However, increased tannin oxidation had no significant impact on oxidative stress in the surrounding midgut tissues. Although growth efficiencies were decreased by hydrolyzable tannins, growth rates remained unchanged, suggesting that additional hydrolyzable tannins are not sufficient to increase the resistance of oak. In larvae on condensed tannin-coated maple, no antioxidant effects were observed in the midgut, and levels of tannin oxidation remained high. Consequently, neither oxidative stress in midgut tissues nor larval performance were significantly affected by high levels of condensed tannins. Post hoc comparisons of physiological mechanisms related to tree resistance revealed that maple produced not only higher levels of oxidative stress in the midgut lumen and midgut tissues of L. dispar, but also decreased protein utilization efficiency compared with oak. Our results suggest that high levels of hydrolyzable tannins are important for producing oxidative stress, but increased tree resistance to caterpillars may require additional factors, such as those that produce nutritional stress.     

Expression of connexin 37, 40 and 43 in rat mesenteric arterioles and resistance arteries

Connexins are the protein constituents of gap junctions which mediate intercellular communication in most tissues. In arterioles gap junctions appear to be important for conduction of vasomotor responses along the vessel. Studies of the expression pattern of connexin isoforms in the microcirculation are sparse. We investigated the expression of the three major vascular connexins in mesenteric arterioles (diameter <50 micro m) from male Sprague-Dawley rats, since conducted vasomotor responses have been described in these vessels. The findings were compared with those obtained from upstream small resistance arteries. Indirect immunofluorescence techniques were used on whole mounts of mesenteric arterioles and on frozen sections of resistance arteries (diameter approximately 300 micro m). Mesenteric arterioles expressed Cx40 and Cx43 in the endothelial layer, and Cx37 was found in most but not all vessels. Connexins were not demonstrated in the media. In resistance arteries endothelial cells expressed Cx37, Cx40 and Cx43. Ultrastructural studies of mesenteric arterioles confirmed that gap junction plaques between endothelial cells are present, whereas myoendothelial, or smooth muscle cell gap junctions could not be demonstrated. The findings suggest that smooth muscle cells in mesenteric arterioles may not be well coupled and favour that conducted vasomotor responses in these vessels are propagated through the endothelial cell layer.     

QTL analysis of the spring wheat “Chapio” identifies stable stripe rust resistance despite inter-continental genotype × environment interactions

Chapio is a spring wheat developed by CIMMYT in Mexico by a breeding program that focused on multigenic resistances to leaf rust and stripe rust. A population consisting of 277 recombinant inbred lines (RILs) was developed by crossing Chapio with Avocet. The RILs were genotyped with DArT markers (137 randomly selected RILs) and bulked segregant analysis conducted to supplement the map with informative SSR markers. The final map consisted of 264 markers. Phenotyping against stripe rust was conducted for three seasons in Toluca, Mexico and at three sites over two seasons (total of four environments) in Sichuan Province, China. Significant loci across the two inter-continental regions included Lr34/Yr18 on 7DS, Sr2/Yr30 on 3BS, and a QTL on 3D. There were significant genotype × environment interactions with resistance gene Yr31 on 2BS being effective in most of the Toluca environments; however, a late incursion of a virulent pathotype in 2009 rendered this gene ineffective. This locus also had no effect in China. Conversely, a 5BL locus was only effective in the Chinese environments. There were also complex additive interactions. In the Mexican environments, Yr31 suppressed the additive effect of Yr30 and the 3D locus, but not of Lr34/Yr18, while in China, the 3D and 5BL loci were generally not additive with each other, but were additive when combined with other loci. These results indicate the importance of maintaining diverse, multi-genic resistances as Chapio had stable inter-continental resistance despite the fact that there were QTLs that were not effective in either one or the other region.     

Mapping QTL associated with resistance to Fusarium head blight in the Nanda2419 × Wangshuibai population. II: Type I resistance

Fusarium head blight (FHB) is a serious disease in wheat and barley affecting both yield and quality. To identify genes for resistance to infection, the RIL population derived from ‘Nanda2419’ × ‘Wangshuibai’ and the parents were evaluated for percentage of infected spikes (PIS) in four different environments. Using a 2,960 cM marker framework map constructed for this population, ten chromosome regions were detected for their association with type I resistance through interval mapping with Mapmaker/QTL, among which QTLs mapped in the intervals of Xwmc349~Xgwm149 on chromosome 4B, of Xwmc96~Xgwm304 on chromosome 5A and of Xgwm408~Xbarc140 on chromosome 5B were revealed in at least three environments and have Wangshuibai as the source of resistance alleles. Qfhi.nau-4B and Qfhi.nau-5A had larger effects and explained up to 17.5 and 27.0% of the phenotypic variance, respectively. To detect epistasis QTLs, two-locus interactions were examined by whole genome scan. Interactions of five locus pairs were found to have significant effects on type I resistance with the LOD score ranging 3.8–6.5 and four of them conferred resistance in parental phase. The one with the most significant effect was Xcfd42~Xgwm469 (6D)/Xwmc390-2~Xbd04 (2A) pair. No QTL × E interaction was detected for PIS. It was found that flowering time did not have significant effects on PIS in this population. Our studies indicated that Wangshuibai is useful for breeding for both type I and type II scab resistance and the markers associated with the QTLs could be used in marker-assisted selection and isolation of scab-resistance QTLs. F. Lin and S.L. Xue equally contributed to this article     

Conditions for Global Dynamic Stability of a Class of Resource-Bounded Model Ecosystems

This paper studies a class of dynamical systems that model multi-species ecosystems. These systems are ‘resource bounded’ in the sense that species compete to utilize an underlying limiting resource or substrate. This boundedness means that the relevant state space can be reduced to a simplex, with coordinates representing the proportions of substrate utilized by the various species. If the vector field is inward pointing on the boundary of the simplex, the state space is forward invariant under the system flow, a requirement that can be interpreted as the presence of non-zero exogenous recruitment. We consider conditions under which these model systems have a unique interior equilibrium that is globally asymptotically stable. The systems we consider generalize classical multi-species Lotka–Volterra systems, the behaviour of which is characterized by properties of the community (or interaction) matrix. However, the more general systems considered here are not characterized by a single matrix, but rather a family of matrices. We develop a set of ‘explicit conditions’ on the basis of a notion of ‘uniform diagonal dominance’ for such a family of matrices, that allows us to extract a set of sufficient conditions for global asymptotic stability based on properties of a single, derived matrix. Examples of these explicit conditions are discussed.     

Mapping of QTL for resistance to the Mediterranean corn borer attack using the intermated B73 × Mo17 (IBM) population of maize

The Mediterranean corn borer or pink stem borer (MCB, Sesamia nonagrioides Lefebvre) causes important yield losses as a consequence of stalk tunneling and direct kernel damage. B73 and Mo17 are the source of the most commercial valuable maize inbred lines in temperate zones, while the intermated B73 × Mo17 (IBM) population is an invaluable source for QTL identification. However, no or few experiments have been carried out to detect QTL for corn borer resistance in the B73 × Mo17 population. The objective of this work was to locate QTL for resistance to stem tunneling and kernel damage by MCB in the IBM population. We detected a QTL for kernel damage at bin 8.05, although the effect was small and two QTL for stalk tunneling at bins 1.06 and 9.04 in which the additive effects were 4 cm, approximately. The two QTL detected for MCB resistance were close to other QTL consistently found for European corn borer (ECB, Ostrinia nubilalis Hübner) resistance, indicating mechanisms of resistance common to both pests or gene clusters controlling resistance to different plagues. The precise mapping achieved with the IBM population will facilitate the QTL pyramiding and the positional cloning of the detected QTL.     

Molecular cytogenetic identification of B genome chromosomes linked to blackleg disease resistance in Brassica napus × B. carinata interspecific hybrids

Key message

Provide evidence that the Brassica B genome chromosome B3 carries blackleg resistance gene, and also the B genome chromosomes were inherited several generations along with B. napus chromosomes.

Abstract

Blackleg disease caused by fungus Leptosphaeria maculans causes significant yield losses in Brassica napus. Brassica carinata possesses excellent resistance to this disease. To introgress blackleg resistance, crosses between B. napus cv. Westar and B. carinata were done. The interspecific-hybrids were backcrossed twice to Westar and self-pollinated three times to produce BC₂S₃ families. Doubled haploid lines (DH1) were produced from one blackleg resistant family. SSR markers were used to study the association between B genome chromosome(s) and blackleg resistance. The entire B3 chromosome of B. carinata was associated with blackleg resistance in DH1. A second DH population (DH2) was produced from F₁s of resistant DH1 lines crossed to blackleg susceptible B. napus cv. Polo where resistance was found to be associated with SSR markers from the middle to bottom of the B3 and top of the B8 chromosomes. The results demonstrated that the B3 chromosome carried gene(s) for blackleg resistance. Genomic in situ hybridization (GISH) and GISH-like analysis of the DH2 lines revealed that susceptible lines, in addition to B. napus chromosomes, possessed one pair of B genome chromosomes (2n = 40), while resistant lines had either one (2n = 40) or two pairs (2n = 42) of B chromosomes. The molecular and GISH data suggested that the B chromosome in the susceptible lines was B7, while it was difficult to confirm the identity of the B chromosomes in the resistant lines. Also, B chromosomes were found to be inherited over several generations along with B. napus chromosomes.     

QTL mapping of stripe,leaf and stem rust resistance genes in a Kariega × Avocet S doubled haploid wheat population

Adult plant resistance to stripe (yellow) rust in the wheat cultivar Kariega has previously been ascribed to a major quantitative trait locus (QTL) on each of chromosomes 2B and 7D, along with a number of minor QTL. We have extended both the size of the cv. Kariega × cv. Avocet S mapping population, and the marker coverage within it, by assembling a set of Diversity Array Technology (DArT) markers. This has allowed for the analysis of the genetic basis of the adult plant and seedling resistances to stripe, leaf and stem rust present in the two mapping population parents. The stripe rust reactions of the segregating material were assessed in both field (three scoring dates) and greenhouse experiments. The chromosome 2B QTL became more important than the Lr34/Yr18 complex on chromosome 7D as the plants aged. As the infection progressed, the two QTL explained an increasing proportion of the variance for percentage leaf area infected. The cv. Kariega allele at the minor chromosome 4A QTL had a consistent effect on the severity of stripe rust infection and the overall plant reaction at the earlier scoring dates, but lost importance as the disease progressed. Several rust resistances were detected using an improved greenhouse-based test.     

The genetic architecture of seedling resistance to Septoria tritici blotch in the winter wheat doubled-haploid population Solitär × Mazurka

Breeding for resistance to Septoria tritici blotch (STB), caused by Mycosphaerella graminicola (anamorph: Septoria tritici), is an essential component in controlling this important foliar disease of wheat. Inheritance of seedling resistance to seven worldwide pathogen isolates has been studied in a doubled-haploid (DH) population derived from a cross between the field resistant cultivar Solitär and the susceptible cultivar Mazurka. Multiple quantitative trait locus (QTL) mapping revealed major and minor genetic effects on resistance as well as several epistatic relationships in the seedling stage. Solitär conferred resistance to isolate IPO323, governed by Stb6 on chromosome 3A, as well as to IPO99015, IPO92034, Hu1 and Hu2 controlled by a QTL on chromosome arm 1BS, possibly corresponding to Stb11 and minor QTL on chromosomes 1B, 3D, 6B and 7D. Resistance of Mazurka to IPO90015 and BBA22 was caused by a QTL located in a region on 4AL which harbours Stb7 or Stb12. QTL specific to pycnidial coverage on 3B and specific to necrosis on 1A could be discovered for isolate IPO92034. Pairwise epistatic interactions were reliably detected with five isolates. Although their contributions to the total variance are generally low, the genotypic effect of the QTL by QTL interaction of 4AL (Stb7 or Stb12) and 3AS (Stb6) made up almost 15% of disease expression. Altogether, the results suggest a complex inheritance of resistance to STB in the seedling stage in terms of isolate-specificity and resistance mechanisms, which have implications for marker-assisted breeding in an attempt to pyramid STB resistance genes.     

Glucose oxidase induces insulin resistance via influencing multiple targets in vitro and in vivo: The central role of oxidative stress

It is well known that reactive oxygen species (ROS) plays a role in the pathogenesis of insulin resistance which is the hallmark of type 2 diabetes. However, it is still needed to clarify the mechanism underlying insulin resistance. Glucose oxidase (GOD) is an oxi-reductase catalyzing the conversion of glucose to glucolactone, which is further converted to glucuronic acid and H(2)O(2). The present study was designed to establish a rat model of insulin resistance using GOD and to investigate possible mechanisms. The results showed that three days administration of GOD could significantly increase fasting blood glucose, resulting in impaired glucose and insulin tolerance. Moreover, GOD disrupted insulin signaling both in rats and in hepatocytes, as evidenced by decreased phosphorylation of insulin-stimulated Akt, GSK3 and FOXO1α. Furthermore, GOD administration decreased the expression of PPARγ, alterated the phosphorylation of MAPKs, including p38, ERK and JNK, increased the expression of GRP78 and reduced the expression of PGC-1α and decreased the activities of ATPase and respiratory complexes, all of which have been reported to contribute to insulin resistance. Redox balance was evaluated by detecting the expression of antioxidant defenses and ROS generation. After the treatment with GOD, nuclear factorerythroid 2 p45-related factor 2 (Nrf2)-regulated antioxidant enzymes were damaged and ROS production increased significantly. N-acetyl-L-cysteine (NAC), a potent antioxidant, could notably inhibit these effects of GOD. Although further studies are needed to investigate the clear mechanism, these data also support the conclusion that, if not the most early event, ROS generation is the most important event that plays a central role in the pathogenesis of insulin resistance. Overall, our study established an insulin resistant animal model induced by GOD, elucidated the importance of ROS in pathogenesis of insulin resistance and provided the clue for further studies on the underlying mechanisms.     

Genetic control of rice blast resistance in the durably resistant cultivar Gumei 2 against multiple isolates

To further our understanding of the genetic control of blast resistance in rice cultivar Gumei 2 and, consequently, to facilitate the utilization of this durably blast-resistant cultivar, we studied 304 recombinant inbred lines of indica rice cross Zhong 156/Gumei 2 and a linkage map comprising 181 markers. An analysis of segregation for resistance against five isolates of rice blast suggested that one gene cluster and three additional major genes that are independently inherited are responsible for the complete resistance of Gumei 2. The gene cluster was located to chromosome 6 and includes two genes mapped previously, Pi25(t), against Chinese rice blast isolate 92-183 (race ZC15) and Pi26(t) against Philippine rice blast isolate Ca89 (lineage 4), and a gene for resistance against Philippine rice blast isolate 92330-5 (lineage 17). Of the two genes conferring resistance against the Philippine isolates V86013 (lineage 15) and C923-39 (lineage 46), we identified one as Pi26(t) and mapped the other onto the distal end of chromosome 2 where Pib is located. We used three components of partial blast resistance, percentage diseased leaf area (DLA), lesion number and lesion size, all measured in the greenhouse, to measure the degree of susceptibility to isolates Ca89 and C923-39 and subsequently identified nine and eight quantitative trait loci (QTLs), respectively. Epistasis was determined to play an important role in partial resistance against Ca89. Using DLA measured on lines susceptible in a blast nursery, we detected six QTLs. While different QTLs were detected for partial resistance to Ca89 and C923-39, respectively, most were involved in the partial resistance in the field. Our results suggest that the blast resistance in Gumei 2 is controlled by multiple major genes and minor genes with epistatic effects.     

Environmental Fluctuations and Level of Density-Compensation Strongly Affects the Probability of Fixation and Fixation Times

The probability of, and time to, fixation of a mutation in a population has traditionally been studied by the classic Wright–Fisher model where population size is constant. Recent theoretical expansions have covered fluctuating populations in various ways but have not incorporated models of how the environment fluctuates in combination with different levels of density-compensation affecting fecundity. We tested the hypothesis that the probability of, and time to, fixation of neutral, advantageous and deleterious mutations is dependent on how the environment fluctuates over time, and on the level of density-compensation. We found that fixation probabilities and times were dependent on the pattern of autocorrelation of carrying capacity over time and interacted with density-compensation. The pattern found was most pronounced at small population sizes. The patterns differed greatly depending on whether the mutation was neutral, advantageous, or disadvantageous. The results indicate that the degree of mismatch between carrying capacity and population size is a key factor, rather than population size per se, and that effective population sizes can be very low also when the census population size is far above the carrying capacity. This study highlights the need for explicit population dynamic models and models for environmental fluctuations for the understanding of the dynamics of genes in populations.     

Modeling and Estimation of Kinetic Parameters and Replicative Fitness of HIV-1 from Flow-Cytometry-Based Growth Competition Experiments

Growth competition assays have been developed to quantify the relative fitness of HIV-1 mutants. In this article, we develop mathematical models to describe viral/cellular dynamic interactions in the assay system from which the competitive fitness indices or parameters are defined. In our previous HIV-viral fitness experiments, the concentration of uninfected target cells was assumed to be constant (Wu et al. 2006). But this may not be true in some experiments. In addition, dual infection may frequently occur in viral fitness experiments and may not be ignorable. Here, we relax these two assumptions and extend our earlier viral fitness model (Wu et al. 2006). The resulting models then become nonlinear ODE systems for which closed-form solutions are not achievable. In the new model, the viral relative fitness is a function of time since it depends on the target cell concentration. First, we studied the structure identifiability of the nonlinear ODE models. The identifiability analysis showed that all parameters in the proposed models are identifiable from the flow-cytometry-based experimental data that we collected. We then employed a global optimization approach (the differential evolution algorithm) to directly estimate the kinetic parameters as well as the relative fitness index in the nonlinear ODE models using nonlinear least square regression based on the experimental data. Practical identifiability was investigated via Monte Carlo simulations.     

Serological identification and molecular characterization of B (A) 02 subtype in patients and blood donors from Eastern China

This study was designed to identify the rare?type?ABO?blood?groups, B(A) 02, from Eastern China. Three samples with discordant serological results during routine blood type identification and four samples from one sample’ family were selected. All of them were detected by serological method. The exon 6 and 7 of the ABO genes were amplified by PCR and sequenced. They were typed as AsubB by serology and as BO by genotype. In AsubB samples, nt 700C>G mutation was detected in B gene, which was previously defined as B(A)02 alleles. In these seven samples, six showed B(A)02/O01 and one showed B(A)02/O02.B(A)02 allele was found to be more common in this study than B(A)04 which is considered to be more frequent than B(A)02. The careful identification of rare blood types is important for the safety of clinical blood transfusion.     

Refined mapping of the Pierce’s disease resistance locus, PdR1, and Sex on an extended genetic map of Vitis rupestris × V. arizonica

A framework genetic map based on genomic DNA-derived SSR, EST-derived SSR, EST-STS and EST-RFLP markers was developed using 181 genotypes generated from D8909-15 (female) × F8909-17 (male), the ‘9621’ population. Both parents are half siblings with a common female parent, Vitis rupestris ‘A. de Serres’, and different male parents (forms of V. arizonica). A total of 542 markers were tested, and 237 of them were polymorphic for the female and male parents. The female map was developed with 159 mapped markers covering 865.0 cM with an average marker distance of 5.4 cM in 18 linkage groups. The male map was constructed with 158 mapped molecular markers covering 1055.0 cM with an average distance of 6.7 cM in 19 linkage groups. The consensus ‘9621’ map covered 1154.0 cM with 210 mapped molecular markers in 19 linkage groups, with average distance of 5.5 cM. Ninety-four of the 210 markers on the consensus map were new. The ‘Sex’ expression locus segregated as single major gene was mapped to linkage group 2 on the consensus and the male map. PdR1, a major gene for resistance to Pierce’s disease, caused by the bacterium Xylella fastidiosa, was mapped to the linkage group 14 between markers VMCNg3h8 and VVIN64, located 4.3 and 2.7 cM away from PdR1, respectively. Differences in segregation distortion of markers were also compared between parents, and three clusters of skewed markers were observed on linkage groups 6, 7 and 14.