Case report: Novel TBX5-related pathogenic mechanism of Holt-Oram syndrome.

Introduction: Holt-Oram syndrome (HOS) is a rare genetic disorder characterized by upper limb abnormalities, congenital heart defects, and/or conduction abnormalities. Sequence alteration of T-box transcription factor 5 (TBX5) is correlated with the incidence of HOS. Case description: We present the case of a 24-year-old female with upper limb alterations (congenital dysplasia in the wrist and elbow joints) and an anomalous left main trunk arising from the right coronary sinus. The patient inherited a base T (reference C) at rs883079 from her mother and base C (reference T) at rs10850326 from her father, both of which belong to the 3'-untranslated region (UTR) of the TBX5 gene; no alterations in TBX5 expression or single-nucleotide polymorphisms (SNPs) in other exon areas were found. We explored the effects of TBX5 on cardiomyocytes using the HL-1 cell line and TBX5-knockdown cells. Discussion: Quantitative polymerase chain reaction analysis demonstrated that TEKT2, TEKT4, and SPTB expression decreased after TBX5 knockdown, while chromatin immunoprecipitation analysis further revealed that TBX5 binds to the TEKT2, TEKT4, and SPTB promoter regions to promote gene transcription. Our findings support a novel TBX5-related pathogenic mechanism in HOS.

A successful extracorporeal cardiopulmonary resuscitation for severe status asthmaticus with an ultra-long cardiac arrest.

The mortality of severe asthma with cardiac arrest is still close to 100% even if it is treated with conventional cardiopulmonary resuscitation (CCPR). Extracorporeal cardiopulmonary resuscitation (ECPR) has been widely accepted as an alternative method when CCPR is futile. However, the maximum "low-flow" duration has not been well defined. Here, we reported a 55-year-old male with severe asthma with cardiac arrest, who was successfully treated with ECPR after 100 min of ultra-long CCPR. He was withdrawn from extracorporeal membrane oxygenator and ventilator at 72 h and 14 days after admission respectively and was discharged without permanent neurologic sequelae. This case illustrates the critical role of ECPR as a last resort in near-fatal asthma. For such patients with bystander, starting ECPR after >60 min of CCPR can still obtain satisfactory prognoses.

Human Plasma Transcriptome Implicates Dysregulated S100A12 Expression: A Strong, Early-Stage Prognostic Factor in ST-Segment Elevated Myocardial Infarction: Bioinformatics Analysis and Experimental Verification.

The ability of blood transcriptome analysis to identify dysregulated pathways and outcome-related genes following myocardial infarction remains unknown. Two gene expression datasets (GSE60993 and GSE61144) were downloaded from Gene Expression Omnibus (GEO) Datasets to identify altered plasma transcriptomes in patients with ST-segment elevated myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention. GEO2R, Gene Ontology/Kyoto Encyclopedia of Genes and Genomes annotations, protein-protein interaction analysis, etc., were adopted to determine functional roles and regulatory networks of differentially expressed genes (DEGs). Dysregulated expressomes were verified at transcriptional and translational levels by analyzing the GSE49925 dataset and our own samples, respectively. A total of 91 DEGs were identified in the discovery phase, consisting of 15 downregulated genes and 76 upregulated genes. Two hub modules consisting of 12 hub genes were identified. In the verification phase, six of the 12 hub genes exhibited the same variation patterns at the transcriptional level in the GSE49925 dataset. Among them, S100A12 was shown to have the best discriminative performance for predicting in-hospital mortality and to be the only independent predictor of death during follow-up. Validation of 223 samples from our center showed that S100A12 protein level in plasma was significantly lower among patients who survived to discharge, but it was not an independent predictor of survival to discharge or recurrent major adverse cardiovascular events after discharge. In conclusion, the dysregulated expression of plasma S100A12 at the transcriptional level is a robust early prognostic factor in patients with STEMI, while the discrimination power of the protein level in plasma needs to be further verified by large-scale, prospective, international, multicenter studies.

Liraglutide reduces hyperglycemia-induced cardiomyocyte death through activating glucagon-like peptide 1 receptor and targeting AMPK pathway.

Objective: Hyperglycemia-mediated cardiomyocyte damage is associated with inflammation and AMPK inactivation.Aim: The aim of our study is to explore the protective effects exerted by liraglutide on AMPK pathway and glucagon-like peptide 1 receptor in diabetic cardiomyopathy.Methods: Cardiomyocytes were treated with high-glucose stress and cardiomyocyte viability was determined via (3-(4,5-dimethylthiazol-2-yl)-2,5diphenyltetrazolium bromide assay. Besides, LDH release, immunofluorescence, and qPCR were used to verify the influence of liraglutide on hyperglycemia-treated cardiomyocytes.Results: Hyperglycemia treatment caused inflammation response and oxidative stress were significantly elevated in cardiomyocytes. This alteration could be reversed by liraglutide. Besides, cell viability was reduced whereas apoptosis was increased after exposure to high glucose treatment. However, liraglutide treatment could attenuate apoptosis and reverse cell viability in cardiomyocyte. Further, we found that AMPK pathway was also activated and glucagon-like peptide 1 receptor expression was increased in response to liraglutide treatment.Conclusions: Liraglutide could attenuate hyperglycemia-mediated cardiomyocyte damage through reversing AMPK pathway and upregulating glucagon-like peptide 1 receptor.

Metoprolol protects cardiomyocytes in rabbit model of heart failure by regulating Cx43.

This study investigated the protective effect of metoprolol on cardiomyocytes in rabbits with heart failure and its possible mechanism. Sixty New Zealand white rabbits were randomly divided into infarction group and non-infarction group, 30 in each group. Myocardial infarction was constructed by ligation of anterior descending branch of coronary artery. Coronary artery threading without ligation after thoracotomy was performed for rabbits in non-infarction group. After model construction, rabbits in each group were further divided into control group (n=15) and metoprolol group (n=15), and fed with normal diet and normal diet + metoprolol. Animals were sacrificed 8 weeks later, and ventricular tissue around infarction area was collected. Expression of connexin 43 (Cx43) in myocardium was detected by immunohistochemistry. Expression of Cx43 protein and mRNA in each group was detected by western blot and reverse transcription PCR. The Cx43 protein was positively expressed in non-infarction group and was evenly distributed in intercellular space. Compared with non-infarction group, expression of Cx43 in infarction group was significantly decreased or even disappeared, while the decrease in expression level of Cx43 and the degree of dispersion were lower in metoprolol group than in control group. There was no significant difference in expression of level of Cx43 protein and mRNA between the subgroups of non-infarction group (P>0.05). In infarction group, expression level of Cx43 protein and mRNA in the metoprolol group were significantly higher than those in control group (P<0.05). The results showed that metoprolol can protect cardiomyocytes after myocardial infarction, and the possible mechanism is related to the regulation of Cx43 expression in cardiomyocytes.

Dwarf and tiller-enhancing 1 regulates growth and development by influencing boron uptake in boron limited conditions in rice.

Boron (B) is essential for plant growth, and B deficiency causes severe losses in crop yield. Here we isolated and characterized a rice (Oryza sativa L.) mutant named dwarf and tiller-enhancing 1 (dte1), which exhibits defects under low-B conditions, including retarded growth, increased number of tillers and impaired pollen fertility. Map-based cloning revealed that dte1 encodes a NOD26-LIKE INTRINSIC PROTEIN orthologous to known B channel proteins AtNIP5;1 in Arabidopsis and TASSEL-LESS1 in maize. Its identity was verified by transgenic complementation and RNA-interference. Subcellular localization showed DTE1 is mainly localized in the plasma membrane. The accumulation of DTE1 transcripts both in roots and shoots significantly increased within 3h of the onset of B starvation, but decreased within 1h of B replenishment. GUS staining indicated that DTE1s are expressed abundantly in exodermal cells in roots, as well as in nodal region of adult leaves. Although the dte1 mutation apparently reduces the total B content in plants, it does not affect in vivo B concentrations under B-deficient conditions. These data provide evidence that DTE1 is critical for vegetative growth and reproductive development in rice grown under B-deficient conditions.

Overexpression of folate biosynthesis genes in rice (Oryza sativa L.) and evaluation of their impact on seed folate content.

Folate (vitamin B9) deficiency is a global health problem especially in developing countries where the major staple foods such as rice contain extremely low folates. Biofortification of rice could be an alternative complement way to fight folate deficiency. In this study, we evaluated the availability of the genes in each step of folate biosynthesis pathway for rice folate enhancement in the japonica variety kitaake genetic background. The first enzymes GTP cyclohydrolase I (GTPCHI) and aminodeoxychorismate synthase (ADCS) in the pterin and para-aminobenzoate branches resulted in significant increase in seed folate content, respectively (P < 0.01). Overexpression of two closely related enzymes dihydrofolate synthase (DHFS) and folypolyglutamate synthase (FPGS), which perform the first and further additions of glutamates, produced slightly increase in seed folate content separately. The GTPCHI transgene was combined with each of the other transgenes except ADCS to investigate the effects of gene stacking on seed folate accumulation. Seed folate contents in the gene-stacked plants were higher than the individual low-folate transgenic parents, but lower than the high-folate GTPCHI transgenic lines, pointing to an inadequate supply of para-aminobenzoic acid (PABA) precursor initiated by ADCS in constraining folate overproduction in gene-stacked plants.

Dissecting genetic networks underlying complex phenotypes: the theoretical framework.

Great progress has been made in genetic dissection of quantitative trait variation during the past two decades, but many studies still reveal only a small fraction of quantitative trait loci (QTLs), and epistasis remains elusive. We integrate contemporary knowledge of signal transduction pathways with principles of quantitative and population genetics to characterize genetic networks underlying complex traits, using a model founded upon one-way functional dependency of downstream genes on upstream regulators (the principle of hierarchy) and mutual functional dependency among related genes (functional genetic units, FGU). Both simulated and real data suggest that complementary epistasis contributes greatly to quantitative trait variation, and obscures the phenotypic effects of many 'downstream' loci in pathways. The mathematical relationships between the main effects and epistatic effects of genes acting at different levels of signaling pathways were established using the quantitative and population genetic parameters. Both loss of function and "co-adapted" gene complexes formed by multiple alleles with differentiated functions (effects) are predicted to be frequent types of allelic diversity at loci that contribute to the genetic variation of complex traits in populations. Downstream FGUs appear to be more vulnerable to loss of function than their upstream regulators, but this vulnerability is apparently compensated by different FGUs of similar functions. Other predictions from the model may account for puzzling results regarding responses to selection, genotype by environment interaction, and the genetic basis of heterosis.

The distribution of japonica rice cultivars in the lower region of the Yangtze River valley is determined by its photoperiod-sensitivity and heading date genotypes.

There are generally four recognized classes of japonica rice cultivars grown in the lower region of the Yangtze River valley. The geographical distribution of the four classes is latitude-dependent. Variation for heading date (HD) among 29 japonica rice cultivars grown in the lower region of the Yangtze River valley and belonging to the four classes was characterized, and their sensitivity to variations in photoperiod and temperature was analyzed. All of the cultivars were sensitive to both photoperiod and temperature. A regression analysis showed that HD is closely correlated with photoperiod sensitivity (PS). The PS of the four classes increased gradually from the medium maturing middle (MMM) types, through the late maturing middle (LMM) and early maturing late (EML) types to the medium maturing late (MML) types. Crosses with tester lines established that almost all of the cultivars carry the dominant early-heading allele at Ef-1, the photoperiod insensitive allele e(2) and the PS alleles E(1) or E(1) (t). Most of the MMM, LMM and MML types carry the insensitive allele e(3), while EML types have either E(3) or E(3) (t). At Se-1, MMM and LMM types have Se-1(e), some EML types have Se-1(e) and others Se-1(n), while the MML types are mostly Se-1(n). The PS of some MMM, LMM and EML types is reduced by the presence of hd2. These results show that the distribution of the four rice cultivar classes from high latitude to low latitude regions depended on a gradual increase in PS, which is mainly determined by its HD genotypes.

[Current status and strategies for improvement of rice grain chalkiness].

This paper reviews the current status of correlation between rice chalkiness and other rice quality characters, formative mechanism, and classical and molecular genetics for rice chalkiness. The formation of rice chalkiness proves to be a complicated physiological process and tightly relate to "source-sink" of rice, dynamics of grain filing, biosynthesis and accumulation of starch in endosperm. Rice chalkiness is a complicated quantitative trait, which is controlled by maternal effects, endosperm effects, and cytoplasmic effects. There are some stable quantitative trait loci (QTL) for rice chalkiness on many rice chromosomes. Of them, three genes controlling rice chalkiness, which have an impact on starch synthesis, starch metabolism, and fruit development, have been cloned. But the manipulative network and formative mechanisms of rice chalkiness remain unclear. At present in breeding practice, decrease of rice chalkiness has become one of the main aims in rice quality breeding, especially for indica rice. The direction of genetic research and improvement strategy of rice chalkiness in future were discussed in this review.

Quantitative trait loci mapping of resistance to Laodelphax striatellus (Homoptera: Delphacidae) in rice using recombinant inbred lines.

Laodelphax striatellus Fallén (Homoptera: Delphacidae), is a serious pest in rice, Oryza sativa L., production. A mapping population consisting of 81 recombinant inbred lines (RILs), derived from a cross between japonica' Kinmaze' and indica' DV85' rice, was used to detect quantitative trait loci (QTLs) for the resistance to L. striatellus. Seedbox screening test (SST), antixenosis test, and antibiosis test were used to evaluate the resistance response of the two parents and 81 RILs to L. striatellus at the seedling stage, and composite interval mapping was used for QTL analysis. When the resistance was measured by SST method, two QTLs conferring resistance to L. striatellus were mapped on chromosome 11, namely, Qsbph11a and Qsbph11b, with log of odds scores 2.51 and 4.38, respectively. The two QTLs explained 16.62 and 27.78% of the phenotypic variance in this population, respectively. In total, three QTLs controlling antixenosis against L. striatellus were detected on chromosomes 3, 4, and 11, respectively, accounting for 37.5% of the total phenotypic variance. Two QTLs expressing antibiosis to L. striatellus were mapped on chromosomes 3 and 11, respectively, explaining 25.9% of the total phenotypic variance. The identified QTL located between markers XNpb202 and C1172 on chromosome 11 was detected repeatedly by three different screening methods; therefore, it may be important to confer the resistance to L. striatellus. Once confirmed in other mapping populations, these QTLs should be useful in breeding for resistance to L. striatellus by marker-assisted selection of different resistance genes in rice varieties.

Mapping and marker-assisted selection of a brown planthopper resistance gene bph2 in rice (Oryza sativa L.).

Nilaparvata lugens Stål (brown planthopper, BPH), is one of the major insect pests of rice (Oryza sativa L.) in the temperate rice-growing region. In this study, ASD7 harboring a BPH resistance gene bph2 was crossed to a susceptible cultivar C418, a japonica restorer line. BPH resistance was evaluated using 134 F2:3 lines derived from the cross between "ASD7" and "C418". SSR assay and linkage analysis were carried out to detect bph2. As a result, the resistant gene bph2 in ASD7 was successfully mapped between RM7102 and RM463 on the long arm of chromosome 12, with distances of 7.6 cM and 7.2 cM, respectively. Meanwhile, both phenotypic selection and marker-assisted selection (MAS) were conducted in the BC1F1 and BC2F1 populations. Selection efficiencies of RM7102 and RM463 were determined to be 89.9% and 91.2%, respectively. It would be very beneficial for BPH resistance improvement by using MAS of this gene.

SSR mapping of brown planthopper resistance gene Bph9 in Kaharamana, an Indica rice (Oryza sativa L.).

The brown planthopper (BPH) is one of the most serious insects pests of rice, and the host resistance has been recognized as one of the most economic and effective measures for BPH management. In this study, we conducted a molecular-based genetic analysis of Bph9 in Kaharamana, a Sri Lanka rice variety resistant to BPH insects of East and Southeast Asia. An F2 segregating population composed of 180 plants was constructed from the cross between Kaharamana and 02428, and each F2 plant was self-crossed to obtain F2:3 family. The bulked seedling test method was used to evaluate the resistance of F2:3 families, and the genotype of each F2 plant was inferred from the phenotype of corresponding F2:3 family. Linkage analysis indicated that the resistant gene Bph9 in Kaharamana was located between SSR markers RM463 and RM5341 on chromosome 12 with linkage distances of 6.8 cM and 9.7 cM, respectively. The time- and money-saving SSR markers would be helpful in the application of Bph9 in breeding program via marker-assisted selection.

[Rapid determination of transient expression characteristics of drought- and dehydration-inducible promoters from plants].

The selection of suitable inducible-promoters is one of the most important chains in transgenic researches for plant tolerances to drought, dehydration and other abiotic stresses. Based on laboratory researches in the past years, it was set up a set of methods that could be used to rapidly determine the transient expression characteristics of drought- and dehydration-inducible promoters by using whole barley seedling and plant leaves in vitro as bombardment objects. Promoters Dhn4s, Dhn8s, HVA1s, Rab16Bj and wsi18j isolated from barley and rice were able to express GFP in the leaves of barley, wheat, rice, sorghum and fern after drying treatment, but not in laves of mungbean and tomato. The qualitative expression of HVA1s and wsi18j in different organs and tissues of barley was identified. A method for quantitative analysis of promoter transient expression was established by means of GFP foci/GUS foci counting or GUS activity/XYN activity test. Finally, the value and prospect of the methodology were discussed in terms of its application to the analysis of plant promoters inducible by environmental factors.

Mapping of QTLS for ferrous iron toxicity tolerance in rice (Oryza sativa L.).

Ferrous iron toxicity is the main factor limiting the productivity of rice in gleyic paddy soils. In this study, an F2 and an equivalent F3 populations derived from a japonica/indica cross of rice, Longza8503/IR64, were raised under iron-enriched solution cultures, and used to map QTLs controlling ferrous iron toxicity tolerance. A genetic linkage map consisting of 101 SSR markers was constructed to determine the position and nature of quantitative trait loci (QTLs) affecting Fe2+ toxicity tolerance. Three characters, i.e., leaf bronzing index (LBI), plant height (PH) and maximum root length (MRL) were evaluated for the F2 plants and F3 lines and the parents at the seedling stage in nutrient solution. A total of 20 QTLs for LBI, PH and MRL under the Fe2+ stress were detected over 10 of the 12 rice chromosomes, reflecting multigenic control of these traits. QTLs controlling LBI were located at the region of RM315-RM212 on chromosome 1, RM6-RM240 on chromosome 2 and RM252-RM451 on chromosome 4. Compared with other mapping results: (1) the QTL for LBI located at the region of RM252-RM451 on chromosome 4 was identical with the QTL for decreased chlorophyll content on a rice function map. Another QTL for LBI located at the region of RM315-RM212 on chromosome 1 was linked with the QTL for chlorophyll content which located at the region of C178-R2635 on a rice function map. (2) The third QTL for LBI located at the region of RM6-RM240 on choromosome 2 was linked with the QTL for potassium uptake located at the region of RZ58-CDO686 under potassium deficiency stress.

[Changes in some defensive enzyme activity induced by the piercing-sucking of brown planthopper in rice].

The effects of brown planthopper on the activities of some key enzymes involved in defense response and the H(2)O(2) content were investigated in rice. From the fact that after piercing-sucking of brown planthopper, malondialdehyde (MDA) content of rice plant was increased rapidly (Fig.3), one can conclude that it induced lipid peroxidation; lipoxygenase (LOX), hydroperoxide lyase (HPL) and phenylalanine ammonia-lyase (PAL) activities were increased significantly in plants of resistant and susceptible varieties by piercing-sucking of brown planthopper (Figs.1,2,4); whereas the catalase activity and the H(2)O(2) content were significantly different between resistant and susceptible plants by piercing-sucking of brown planthopper, the former being decreased and the latter increased in resistance plants of variety RH (Oryza sativa L. cv. Rathu Heenati), while the reverse was true in the susceptible plants of variety TN1 (Oryza sotiva L. cv. Taichung Native 1) (Figs.5,6). The effect of brown planthopper on the PAL activity and the H(2)O(2) content were systemic (Figs.4,6), but the effect on the LOX activity occurred only in stem, the organ which brown planthopper sucking (Fig.1).

[QTLs mapping and genetic analysis of tiller angle in rice (Oryza sativa L.)].

Tiller angle is one of the most important morphological characters that has a significant effect on the formation of rice high-yield population. The tiller angles were measured in a japonica/indica RIL population with 71 lines and a genome-wide chromosome segment substitution line (CSSL) population with 65 lines at two experimental sites. A transgressive segregation was observed in both populations. QTL analysis of tiller angle was conducted based on the saturated RFLP marker linkage map and the CSSL graphical genetype. Five main-effect QTLs and three pairs of epstatic loci were detected in the RIL population. A main QTL, qTA-9, located on chromosome 9 at XNpb108 - C506, was identified at both experiment sites. The positive allele TA-9(I) on qTA-9 was contributed by indica rice IR24 with 28.6% average contribution to variance. Meanwhile, an analysis of CSSL graphical genetypes also showed that there was a positive allele on the IR24 chromosome substitution segment delimited by RFLP marker C609 and C506 with approximate 15 cM interval, which proved the existence of qTA-9. The TA-9(I) could increase tiller angle by about 15 degrees in japonica Asominori background under the two environments. The measurement of the F1 from the cross between background parent and CSSL AIS68 with TA-9(I) and the analysis of F2 population indicated that the TA-9(I) was an incomplete dominant gene. Genetype x environment interaction(G xE) was not widely present except a pair of epistatic loci with 5.32% contribution to variance of tiller angles and a relatively small additive effect. The combining action of the additive effect of the genes from both parents and the two-loci epistasis-effect may be responsible for the transgressive segregation of tiller angle in rice population. The value and approach of application of TA-9(I) in hybrid rice breeding program were discussed.

[QTL analysis for traits associated with photosynthetic functions in rice (Oryza sativa L.)].

A mapping population of 81 F11 lines (Recombinant Inbred Lines, RILs), derived from a cross between a japonica variety Kinmaze and an indica variety DV85 by single-seed descent method, was used to detect quantitative trait loci (QTL) for traits associated with photosynthetic functions. Total leaf nitrogen content (TLN), chlorophyll a/b ratio (Chl. a:b) and chlorophyll content (Chl) were measured in leaves of rice (Oryza sativa L.) at the 7th day after heading. A total of six putative QTLs were detected with percentage of variance explained (PVE) ranging between 11.2% -29.6%, and LOD of QTLs 2.66-4.81. Of those putative QTLs, three for TLN were detected on chromosomes 1,2 and 11, with PVE of 17.3%, 15.3% and 13.7%, respectively;Two controlling Chl. a:b on chromosomes 3 and 4, PVE of 13.8% and 29.6%, one for Chl on chromosome 1, PVE of 11.2%. Four of those detected QTLs were newly reported in this study. Interestingly, the QTL controlling chlorophyll content,namely qCC-1 reported here,was detected in the region of the RFLP marker C122 on chromosome 1, where harbored NADH-glutamate synthase structure gene according to a previous study. Because the biosynthesis of chlorophyll begins with glutamate, qCC-1 would play a vital role in photosynthetic functions. Whereas,no QTL controlling chlorophyll content were detected at the 30th day after heading, suggesting that the effect of the QTL controlling chlorophyll content decreased during leaf senescence.

[QTL analysis of low-temperature-sensitive pollen sterility in Indica-japonica hybrid rice (Oryza sativa L.)].

There existed a number of biological constraints in exploiting the heterosis of indica-japonica hybrid rice. The low-temperature-sensitive sterility (LTSS) of indica-japonica hybrid has become one of the major problems in indica-japonica hybrid rice breeding after the solution of poor fertility of the hybrids by the finding of wide-compatibility gene. Previous studies revealed that the LTSS might be caused by low-temperature-sensitive pollen sterility (LTSPS). However, the genetic basis of LTSPS remained unclear. To explore the genetic basis of LTSPS in indica-japonica hybrid rice, an F2 genetic population derived from 3037 (indica) and 02428 (japonica) was developed. At the booting stage, pollen fertility of F2 population together with parents were surveyed after the treatment with low temperature daily average of 21-23 degrees C. The linkage map was constructed containing 108 SSR markers distributed throughout the whole 12 chromosomes with average marker interval of 16.26 cM. Using software MapMaker/QTL, two putative QTLs, namely qLTSPS2 and qLTSPS5 on chromosomes 2 and 5 were detected by interval mapping, which could explain the phenotypic variation 15.6% and 11.9% respectively. The additive effects were 0.021 and 0.045, dominant effects were -0.246 and -0.215, and the degrees of dominance were 11.7 and 4.8, respectively for the two QTLs. Therefore, the mode of gene action in response to low-temperature stress was overdominance and LTSPS was mainly the result of interaction between the indica and japonica alleles within each locus. In addition, two-way ANOVA showed that the two QTLs acted essentially independent of each other in conditioning LTSPS.

[Stable expression of QTL for grain shape of milled rice (Oryza sativa L. ) using a CSSLs population].

A set of chromosome segment substitution lines (CSSLs), derived from Asominori/IR24 with Asominori as the recurrent parent,was planted and phenotyped for grain length (GL), grain width (GW) and length-width ratio (LWR) of milled rice in two successive years and four sites. QTL for GL,GW and LWR were characterized and stability of their expression was investigated. The phenotypic values for each trait showed a continuous distribution and some transgressive lines were also observed in the CSSLs population. Additionally, a total of 13 QTL for GL, GW and LWR were identified,and six of them were consistently detected in the eight different environments. Phenotypic values were different significantly (P < 0. 001) between the CSSLs harboring any of the six QTL alleles and the genetic background parent, Asominori. Significant phenotypic correlations (r > or = 0.75, r0.05 = 0.67) were detected among different environments for these CSSLs carrying the same target QTL. Also, the results indicated that the six QTL, namely, qGL-3 for GL, qGW-5a and qGW-5b for GW, qLWR-3, qLWR-5a and qLWR-5b for LWR, were stably expressed in different environments. Since QTL qGL-3 and qLWR-3 were mapped in the R19-C1677 interval, qGW-5a and qLWR-5a in the vicinity of RFLP marker C263, qGW-5b and qLWR-5b near R569,the four RFLP markers, R19, C1677, C263 and R569,would be useful for further marker-assisted selection (MAS) in rice quality improvement.