Genetic Polymorphism of Wx Gene and Its Correlation with Main Grain Quality Characteristics in Rice

The allelic variation of the Wx gene in 50 non-glutinous rice varieties （lines） was analyzed by using the microsatellite marker RM190 [for （CT）n simple sequence repeat （SSR）] and cleaved amplified polymorphic sequence（CAPS） marker 484/W2R-ACCⅠ[for G/T single nucleotide polymorphism （SNP）]. Six homozygous （CT）n types, namely （CT）20, （CT）19, （CT）18, （CT）17, （CT）16, （CT）14, （CT）11 and （CT）10, and a heterozygous genotype （CT）11/（CT）18 were detected for RM190, of which （CT）11 and （CT）18 were predominant. Two homozygous Wx genotypes （G/G and T/T） and one heterozygous （G/T） were detected using 484/W2R-ACC Ⅰ. Most of the materials with a RM190 of （CT）11 were G/G for SNP of 484/W2R-ACC Ⅰ, while T/T for SNP was predominantly appeared in materials with （CT）18. The materials tested could be grouped into 10 categories using the two markers together. Results indicated that 59.3% variance of amylose content was attributed to the polymorphism of Wx gene revealed by RM190, while 56.1% and 24.6% of the variances in amylose content and gel consistency were respectively to the polymorphism of Wx gene revealed by 484/W2R-ACC Ⅰ. Furthermore, with both SSR and CAPS markers, 72.4% of the variance in amylose content could be explained. In addition, the application prospects of the two markers in breeding were also discussed.

Identification and Cloning of Tillering-Related Genes OsMAX1 in Rice

Tillering is an important agronomic trait which has a direct impact on plant type and grain yield. Strigolactones are a class of important phytohormones regulating rice tillering. ATMAX1 is an important gene involved in strigolactone biosynthesis through encoding the protein P450 in Arabidopsis. Based on sequence BLASTp, we identified five homologous genes of ATMAX1 in rice, i.e., OsMAXla, OsMAXlb, OsMAXlc, OsMAXld and OsMAXle. Among them, OsMAXla and OsMAXle showed stable and high expression in rice tissues. In addition, we observed that OsMAXla and OsMAXle can rescue the branched phenotype and the influences caused by MAX1 mutation in Arabidopsis. Moreover, the expression of OsMAX1a and OsMAXle can respond to phosphate deficiency and different phytohormones, especially GR24, a strigolactone analogue. Therefore, it is concluded that OsMAX1a and OsMAX1e are involved in the biosynthesis of strigolactones and regulated rice tillering.

Breeding Rice Restorer Lines with High Resistance to Bacterial Blight by Using Molecular Marker-Assisted Selection

Two bacterial blight （BB） resistance genes, Xa21 and Xa4, from IRBB24 were introduced into hybrid rice restorer line Mianhui 725, which is highly susceptible to BB, by using hybridization and molecular marker-assisted selection technology. Four homologous restorer lines were obtained through testing the R target genes with molecular markers and analyzing parental genetic background. Inoculation of the four lines and their hybrids with the specific strains of Xanthomonas oryzae pv. oryzae, P1, P6 and seven representative strains of Chinese pathotype, C Ⅰ -CⅦ, showed that all of the four lines and their hybrids were highly resistant and presented broad resistance-spectrum to BB. The hybrids of G46A / R207-2 displayed good agronomic characters and high yield potential, and R207-2 was named Shuhui 207.

Genetic Analysis and Mapping of Dominant Minute Grain Gene Mi3(t) in Rice

Grain size, determined chiefly by grain length, is one of the main factors affecting the grain yield in rice production. To study the trait of rice grain size, F1 and F2 populations were developed from crosses Shuhui 881/Y34 and Shuhui 527/Y34, and genetic analysis for minute grain was performed. The F1 populations showed minute grains, and grain size segregations in the two F2 populations were both in accordance with the ratio of 3：1, indicating that minute grain in Y34 was controlled by a completely dominant gene. By using the F2 population from Shuhui 881/Y34, this dominant gene, tentatively designated as Mi3（t）, was mapped based on SSR markers in the interval between RM282 （genetic distance of 5.1 cM） and RM6283 （genetic distance of 0.9 cM） on the short arm of chromosome 3.

不同b值表观扩散系数在鉴别肺癌病理类型及腺癌分化程度中的价值

目的:评价不同b值下DWI鉴别肺癌病理类型及腺癌分化程度的价值。方法:对64例肺癌行常规MRI和DWI检查,分别测量b值为300 s/mm 2、500 s/mm 2、800 s/mm 2时的病变表观扩散系数(ADC)值,比较不同b值下肺鳞癌与肺腺癌、中分化与低分化肺腺癌的ADC值的差异。根据ROC曲线确定各个b值下的ROC曲线下面积及诊断阈值。结果:64例中,鳞癌19例,低分化腺癌29例,中分化腺癌14例。当b=800时测量的平均ADC值对鉴别肺鳞癌与腺癌的诊断效能最高(AUC=0.829),ADC值截断值为0.915 mm 2/s时,敏感性90.7%,特异性66.7%。当b=800时测量的平均ADC值对鉴别低分化腺癌与中分化腺癌的诊断效能最高(AUC=0.863),ADC值截断值为1.173 mm 2/s时,敏感性89.7%,特异性64.3%。结论:b值取800 s/mm 2时,测量平均ADC值对判断肺癌病理类型、腺癌分化程度的诊断效能最高。

“一带一路”沿线国家贸易条件测算与比较分析——基于产品种类变动的视角

随着“一带一路”倡议的推进,如何提升贸易利益、实现共同发展显得尤为重要。利用CEPⅡBACI中“一带一路”沿线国家的贸易数据,测算了其1998—2017年固定产品种类、变动产品种类的贸易条件以及不同技术等级的产品贸易条件,并基于进出口扩展边际、产品种类数量的变化分析贸易条件变化的原因。研究表明:超过半数的沿线国家的平均FTT是改善的,尤其是纳入扩展边际后,其VTT有显著的提升,且技术含量越高的产品,VTT改善程度越大。对比中国与沿线国家的贸易条件与产品种类的变化趋势,建议沿线国家发挥各自优势、深化各国间的经贸、技术合作,同时不仅要通过增加产品种类数量短期内保持贸易条件稳定,而且在长期内要实现创新增长方式由品种增长型向质量升级型转变、推动贸易条件可持续发展。

台湾海峡垃圾污染的两岸合作防控研究

近年来海洋垃圾成为影响和破坏台湾海峡生态环境的主要污染物,给海洋生物和人类活动带来严重影响与危害,海峡两岸合作防控海洋垃圾污染亟待深化。台湾海峡垃圾污染主要源于岸上与海上生产、生活垃圾的排放,加强陆源入海排污口监控、实施海洋垃圾的合理收集与处置至关重要。新形势下,要统一认识,共同推进海洋环保的宣传普及与教育;扎实行动,严格管控工农业生产和生活垃圾排放;扩大保障,确保海峡两岸污染治理的技术和资金;加强互信,积极探讨海洋垃圾污染合作治理方式;试验示范,完善海洋垃圾污染合作防控协调机制,以带动和促进生态环境保护与海峡两岸融合发展。