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28 September 2008, Volume 15 Issue 3 Previous Issue    Next Issue
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Molecular-Cytological Identification and Chromosome Behavior Analysis of Telotetrasomic in Rice GONG Zhi-yun, GAO Qing-song, YU Heng-xiu, YI Chuan-deng, GU Ming-hong 2008, 15(3): 161-165 .  Abstract ( )   PDF   From the progenies of a telotrisomic of chromosome 9 short arm of an indica rice variety, Zhongxian 3037, a phenotypical variant was selected. The variant plant had rolled leaves, dispersed plant type, as well as a low seed-setting rate. Cytological and molecular cytological investigations revealed two extra chromosomes, which were the shortest in somatic cells of the variant. Fluorescent in situ hybridization (FISH) analysis using a rice centromere specific DNA (RCS2) and a DNA sequence specific for chromosome 9 on premetaphase and pachytene chromosomes showed that these two chromosomes were the short arms of chromosome 9. That is to say, the variant was a telotetrasomic of chromosome 9. Among the 25 pachytene cells, the two telosomic chromosomes paired each other to form a bivalent and didn’t pair with other normal chromosome 9 as multivalents in 96% cells. However, the bivalent was easy to disassociate in advance.

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A Rice CaMBP Gene is Induced in Organ-Specific Manner by Both Chilling and Heat-Shock Treatments WAN Jia, XI Jiang, DU Zhi-ru, XU Zheng-jun, 2008, 15(3): 166-172 .  Abstract ( )   PDF   A rice CaMBP gene, OsCaMBP (AB363406), was isolated from a chilling treated rice using the fluorescent differential display (FDD) screening method. Its cDNA sequence (2094 bp) contains an opening reading frame (ORF) encoding a 569 amino acids protein (63.2 kD). OsCaMBP has the typical structural features of the CaMBP family, including the conserved IQ calmodulin-binding motif at the N-terminus. Homology analysis revealed 38.25%–47.28% identities of OsCaMBP with other CaMBPs in plants. RT-PCR analysis showed that the expression of OsCaMBP was remarkably inducible under the chilling (8°C) and heat-shock (42°C) treatments. OsCaMBP was undetectable under the normal conditions, and induced under the chilling treatment for 1 h, as well as the heat-shock treatment for 15 min, suggesting that the gene plays important roles in the signaling pathway in rice under both chilling and heat-shock stresses.

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Over-Expression of ICE1 Gene in Transgenic Rice Improves Cold Tolerance XIANG Dian-jun, HU Xiang-yang, ZHANG Yu, YIN Kui-de 2008, 15(3): 173-178 .  Abstract ( )   PDF   ICE1, an Arabidopsis thaliana transcription factor gene, was cloned by RT-PCR and successfully transformed into rice variety Kenjiandao 10 by the Agrobacterium-mediated transformation method. PCR amplification and Southern blot analysis indicated that ICE1 had been integrated into rice genome. Compared with the non-transgenic plants, the transgenic plants exhibited high resistance to hygromycin B and were consistent with the Mendelian inheritance of a single copy of the transgenic ICE1. Under the low temperature stress, the transgenic plants showed the lower mortality rate and the increased proline content. These results suggest that the Arabidopsis ICE1 is functional in rice and the over-expression of ICE1 improves the tolerance to cold stress in rice.

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Improving Blast Resistance of a Thermo-Sensitive Genic Male Sterile Rice Line GD-8S by Molecular Marker-Assisted Selection LIU Wu-ge, JIN Su-juan, ZHU Xiao-yuan, WANG Feng, LI Jin-hua, LIU Zhen-rong, LIAO Yi-long, ZHU Man-shan, HUANG Hui-jun, LIU Yi-bai 2008, 15(3): 179-185 .  Abstract ( )   PDF   The broad-spectrum blast resistance gene Pi-1, from donor line BL122, was introduced into a thermo-sensitive genic male sterile rice line GD-8S, which possessed good grain quality but high susceptibility to rice blast, by using backcross breeding and molecular marker-assisted selection. Five elite improved male sterile lines, RGD8S-1, RGD8S-2, RGD8S-3, RGD8S-4 and RGD8S-5, were selected based on the results of molecular marker analysis, spikelet sterility, recovery rate of genetic background and agronomic traits. Thirty-three representative blast isolates collected from Guangdong Province, China were used to inoculate the improved lines and the original line GD-8S artificially. The resistance frequencies of the improved lines ranged from 76.47% to 100%, much higher than that of the original line GD-8S (9.09%). On the agronomic characters, there were no significant differences between the improved lines and GD-8S except for flag leaf length and panicle number per plant. The improved lines could be used for breeding hybrid rice with high blast resistance.

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Inheritance Analysis and QTL Mapping of Rice Starch Viscosity (Rapid Visco Analyzer Profile) Characteristics ZHANG Qiao-feng, ZHANG Ya-dong, ZHU Zhen, ZHAO Ling, ZHAO Qing-yong, XU Ling, WANG Cai-lin 2008, 15(3): 186-194 .  Abstract ( )   PDF   The rice starch viscosity characteristics, which can be indicated by Rapid Visco Analyzer profile (RVA profile), have been proved useful for the evaluation of cooking and eating quality in rice breeding program. To study the inheritance of the RVA profile, an F2 population of Wuyujing 3/Aichi 106 was used. The results indicated that the peak viscosity (PKV) was a typical quantitative character, and the hot paste viscosity (HPV), cool paste viscosity (CPV), setback viscosity (SBV), breakdown viscosity (BDV), and consistence viscosity (CSV) might be controlled by one major gene and several minor genes. To elucidate the genetic basis of the paste viscosity characteristics, a recombinant inbred line (RIL) population derived from Nikken 2/Milyang 23 and its genetic linkage map were used to map the QTLs controlling RVA profiles in 2005 and 2006. A total of 34 QTLs distributed on chromosomes 1, 2, 3, 4, 6, 7 and 8 were detected, including 19 and 15 QTLs in 2005 and 2006, respectively. Eight QTLs were both detected in the two years, qHPV6, qCPV6, qCSV6, qSBV6, and qBDV6 were located on chromosome 6, while qHPV2, qCSV2, and qCPV2 were on chromosome 2.

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QTL Analysis for Traits Associated with Feeding Value of Straw in Rice (Oryza sativa L.) DONG Chen-fei, CAI Qing-sheng, WANG Cai-lin, Jiro HARADA, Keisuke NEMOTO, SHEN Yi-xin 2008, 15(3): 195-200 .  Abstract ( )   PDF   Genetic improvement of the digestibility of rice straw for increasing the utilization of the whole rice plant as feedstuffs is an important way to solve the feedstuffs shortage in southeastern China. To elucidate the genetic basis of the traits affecting the digestibility of rice straw, a rice population of 111 recombinant inbred lines (RILs) derived from a cross of Nekken 2×Gaya was used to map the quantitative traits loci (QTLs) for in vitro dry matter digestion (IVDMD), the percentages of nonstructural carbohydrate (NSC) and acid detergent fiber (exclusive of residual ash, ADFom) in 2005 and 2006. IVDMD was positively correlated with NSC, and negatively correlated with ADFom. A total of 16 QTLs were detected in the two years, and the amounts of variation explained by individual QTLs ranged from 6.9% to 15.5%. Some QTLs for IVDMD and ADFom on chromosome 2 were detected in the two years. On chromosome 2, the interval RM475–RM3515 contained QTLs for IVDMD in the two years and for NSC in 2006 only, while the interval RM3874–RM5305 influenced ADFom in the two years and NSC in 2005 only. At those loci, Gaya contributed favorable alleles to IVDMD and NSC, while Nekken 2 contributed positive alleles to ADFom.

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Anatomical and Chemical Characteristics of a Rolling Leaf Mutant of Rice and Its Ecophysiological Properties BAI Lei, DUAN Zhuang-qin, WANG Jun-min, AN Li-zhe, ZHAO Zhi-guang, CHEN Kun-ming 2008, 15(3): 201-208 .  Abstract ( )   PDF   The anatomical and chemical characteristics of a rolling leaf mutant (rlm) of rice (Oryza sativa L.) and its ecophysiological properties in photosynthesis and apoplastic transport were investigated. Compared with the wild type (WT), the areas of whole vascular bundles and xylem as well as the ratios of xylem area/whole vascular bundles area and xylem area/phloem area were higher in rlm, whereas the area and the width of foliar bulliform cell were lower. The Fourier transform infrared (FTIR) microspectroscopy spectra of foliar cell walls differed greatly between rlm and WT. The rlm exhibited lower protein and polysaccharide contents of foliar cell walls. An obvious reduction of pectin content was also found in rlm by biochemical measurements. Moreover, the rate of photosynthesis was depressed while the conductance of stoma and the intercellular CO2 concentration were enhanced in rlm. The PTS fluorescence, which represents the ability of apoplastic transport, was 11% higher in rlm than in WT. These results suggest that the changes in anatomical and chemical characteristics of foliar vascular bundles, such as the reduction of proteins, pectins, and other polysaccharides of foliar cell walls, participate in the leaf rolling mutation, and consequently lead to the reduced photosynthetic dynamics and apoplastic transport ability in the mutant.

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Elongation of the Uppermost Internode for Changxuan 3S, a Thermo- Sensitive Genic Male Sterile Rice Line XIAO Hui-hai, WANG Wen-long 2008, 15(3): 209-214 .  Abstract ( )   PDF   Changxuan 3S, a thermo-sensitive genic male sterile (TGMS) rice line with eui gene, is derived from the TGMS rice line Pei’ai 64S by irradiation with 350 Gy of 60Co γ-ray. To elucidate the uppermost internode elongation of the TGMS line with eui gene, Changxuan 3S and its parent Pei’ai 64S were used to study the effects of temperature on panicle exsertion. At 24°C, the uppermost internode of Changxuan 3S elongated the fastest from the 4th day before flowering to 0 day (flowering), being 2.1-fold as that of Pei’ai 64S, whereas it elongated slowly during the 12th day to the 4th day before flowering and the 1st to the 3rd day after flowering. The uppermost internode of Changxuan 3S exserted from the flag leaf sheath at 22°C, 24°C and 26°C, and the length of elongated uppermost internode increased with the decreasing temperatures. At 28°C, though the panicles of Changxuan 3S were still enclosed in the leaf sheath, the degree of panicle enclosure was significantly lower compared with Pei’ai 64S. Cytological studies on Changxuan 3S showed that the uppermost internode elongation was attributed to the increase of cell number and cell elongation, and the latter was more significant. Moreover, the numbers of outermost and innermost parenchyma cells and the cell length of the uppermost internode reduced with the increasing temperatures.

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Responses of Yield Characteristics to High Temperature During Flowering Stage in Hybrid Rice Guodao 6 FU Guan-fu, TAO Long-xing, SONG Jian, WANG Xi, CAO Li-yong, CHENG Shi-hua 2008, 15(3): 215-222 .  Abstract ( )   PDF   By sowing at different dates during 2005 and 2006 both in paddy fields and greenhouse, a super hybrid rice combination Guodao 6 and a conventional hybrid rice combination Xieyou 46 (as control) were used to analyze the differences in heat injury index, seed setting rate, grain yield and its components. Guodao 6 showed more stable yield and spikelet fertility, and lower heat injury index than Xieyou 46. Further studies indicated that the spikelet sterility is positively correlated with the average daily temperature and the maximum daily temperature, with the coefficients of 0.8604 and 0.9850 (P<0.05) respectively in Guodao 6. The effect of high temperature injury on seed setting caused by maximum daily temperature was lower than that by average daily temperature during the grain filling stage.

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Plant Temperature and Its Simulation Model of Thermo-Sensitive Genic Male Sterile Rice LU Chuan-gen, XIA Shi-jian, CHEN Jing, HU Ning, YAO Ke-min 2008, 15(3): 223-231 .  Abstract ( )   PDF   Plant temperature (Tp) and its relations to the microclimate of rice colony and irrigation water were studied using a thermo-sensitive genic male sterile (TGMS) rice line, Pei’ai 64S. Significant differences in the daily change of temperature were detected between Tp and air temperature at the height of 150 cm (TA). From 8:00 to 20:00, Tp was lower than TA, but they were similar during 21:00 to next 7:00. The maximum Tp occurred one hour earlier than the maximum TA, though they both reached the minimum at 6:00. Tp fluctuated less than TA. At the same height, during 6:00–13:00, Tp was higher than air temperature (Ta), and Tp reached the maximum one hour earlier than Ta. During the rest time on sunny day, Tp was close to or even a little lower than Ta. On overcast day, Tp was higher than Ta in the whole day, and both maximized at the same time. In addition, Tp was regulated by solar radiation, cloudage and wind speed in daytime, and by irrigation water at night. The present study indicated that a TA of 29.6°C was the critical point, at which Tp was increased or decreased by irrigation water. Tp and the difference between water and air temperatures showed a conic relation. Tp fluctuation was also regulated by the absorption or reflection of solar radiation by leaves during daytime and release of heat energy during nighttime. By analysis on correlation and regression simulation, two models of Tp were established.

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Characterizing and Estimating Fungal Disease Severity of Rice Brown Spot with Hyperspectral Reflectance Data LIU Zhan-yu, HUANG Jing-feng, TAO Rong-xiang 2008, 15(3): 232-242 .  Abstract ( )   PDF   Large-scale farming of agriculture crops requires real-time detection of disease for field pest management. Hyperspectral remote sensing data generally have high spectral resolution, which could be very useful for detecting disease stress in green vegetation at the leaf and canopy levels. In this study, hyperspectral reflectances of rice in the laboratory and field were measured to characterize the spectral regions and wavebands, which were the most sensitive to rice brown spot infected by Bipolaris oryzae (Helminthosporium oryzae Breda. de Hann). Leaf reflectance increased at the ranges of 450 to 500 nm and 630 to 680 nm with the increasing percentage of infected leaf surface, and decreased at the ranges of 520 to 580 nm, 760 to 790 nm, 1550 to 1750 nm, and 2080 to 2350 nm with the increasing percentage of infected leaf surface respectively. The sensitivity analysis and derivative technique were used to select the sensitive wavebands for the detection of rice brown spot infected by B. oryzae. Ratios of rice leaf reflectance were evaluated as indicators of brown spot. R669/R746 (the reflectance at 669 nm divided by the reflectance at 746 nm, the following ratios may be deduced by analogy), R702/R718, R692/R530, R692/R732, R535/R746, R521/R718, and R569/R718 increased significantly as the incidence of rice brown spot increased regardless of whether it’s at the leaf or canopy level. R702/R718, R692/R530, R692/R732 were the best three ratios for estimating the disease severity of rice brown spot at the leaf and canopy levels. This result not only confirms the capability of hyperspectral remote sensing data in characterizing crop disease for precision pest management in the real world, but also testifies that the ratios of crop reflectance is a useful method to estimate crop disease severity.

Short Communication

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Construction of Double Right-Border Binary Vector Carrying Non-Host Gene Rxo1 Resistant to Bacterial Leaf Streak of Rice XU Mei-rong, XIA Zhi-hui, ZHAI Wen-xue, XU Jian-long, ZHOU Yong-li, LI Zhi-kang 2008, 15(3): 243-246 .  Abstract ( )   PDF   Rxo1 cloned from maize is a non-host gene resistant to bacterial leaf streak of rice. pCAMBIA1305-1 with Rxo1 was digested with Sca I and NgoM IV and the double right-border binary vector pMNDRBBin6 was digested with Hpa I and Xma I. pMNDRBBin6 carrying the gene Rxo1 was acquired by ligation of blunt-end and cohesive end. The results of PCR, restriction enzyme analysis and sequencing indicated that the Rxo1 gene had been cloned into pMNDRBBin6. This double right-border binary vector, named as pMNDRBBin6-Rxo1, will play a role in breeding marker-free plants resistant to bacterial leaf streak of rice by genetic transformation.

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Identification of Differentially Expressed Genes Induced by Ammonium Nitrogen in Rice Using mRNA Differential Display ZHU Guo-hui, HUANG Zhuo-lie 2008, 15(3): 247-250 .  Abstract ( )   PDF   RNAs isolated from ammonium- and nitrate-treated rice leaves were used to screen differentially expressed genes through mRNA differential display. A total of 72 bands appeared significant differences and some of them were further confirmed by reverse Northern and Northern blot. The results showed that two genes, A-02 (Oryza sativa drought stress related mRNA) and A-03 (Zea mays partial mRNA for TFIIB-related protein) were highly up-regulated in the ammonium-fed rice leaves. The enzyme assays showed that the activities of the two anti-oxidative enzymes, catalase and peroxidase, and the content of a non-enzymic antioxidant, glutathione, were significantly higher in the ammonium-fed rice leaves than those in the nitrate-fed ones, indicating that the ammonium nutrition might be beneficial for rice plants to improve the stress resistance during growth and development.