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28 September 2009, Volume 16 Issue 3 Previous Issue    Next Issue
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Characterization and Fine Mapping of Non-panicle Mutant (nop) in Rice WU Kun , RAO Yu-chun , HU Jiang , ZHU Guan-lin , ZHANG Guang-hen , HU Xin-ming , GUO Long-biao , WANG Yong-hong , QIAN Qian , ZENG Da-li 2009, 16(3): 165-172 .  DOI: 10.1016/S1672-6308(08)60075-X Abstract ( )   PDF   A mutant of panicle differentiation in rice called non-panicle (nop) was discovered in the progeny of a cross between 93-11 and Nipponbare. The mutant exhibits normal plant morphology but has apparently few tillers. The most striking change in nop is that its panicle differentiation is blocked, with masses of fluffy bract nodes generate from the positions where rachis branches normally develop in wild-type plants. Genetic analysis suggests that nop is controlled by a single recessive gene, which is temporarily named Nop(t). Based on its mutant phenotype, Nop(t) represents a key gene controlling the initiation of inflorescence differentiation. By using simple sequence repeat markers and sequence tagged site markers, Nop(t) gene was fine mapped in a 102-kb interval on the long arm of chromosome 6. These results will facilitate the positional cloning and functional studies of the gene.

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Genetic Control of Germination Ability under Cold Stress in Rice WANG Zhou-fei, WANG Jian-fei, WANG Fu-hua, BAO Yong-mei, WU Yun-yu, ZHANG Hong-sheng 2009, 16(3): 173-180 .  DOI: 10.1016/S1672-6308(08)60076-1 Abstract ( )   PDF   An F9 recombinant inbred lines (RIL) population, derived from a cross between IR28 (Oryza sativa L. spp. indica) and Daguandao (O. sativa L. spp. japonica), was used to construct a molecular linkage map and to identify germination ability including the traits of imbibition rate, germination rate, germination index, root length, shoot length and seed vigor at 14°C for 23 d. A composite interval mapping approach was applied to conduct genetic analysis for germination ability. The frequency distributions of the germination ability traits under the cold stress in the RIL population showed continuous segregation, suggesting they were quantitative traits controlled by several genes. A total of seven QTLs were identified on chromosomes 4, 6 and 9, including two for imbibition rate (qIR-6, qIR-9), one for germination rate (qGR-4), two for germination index (qGI-4-1, qGI-4-2) and two for root length (qRL-4-1, qRL-4-2). There were no detected QTLs controlling shoot length and seed vigor. The phenotypic variance explained by a single QTL ranged from 9.1% to 37.0%, and two major QTLs, qIR-6 and qGI-4-2, accounted for over 30% of the phenotypic variance. The expressions of QTLs were developmentally regulated and growth stage-specific. Most of the QTLs observed here were located in the regions similar to the QTLs for rice cold tolerance reported previously, indicating that these QTLs were reliable. However, qRL-4-2 is not reported before.

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Development of Marker-Free Transgenic Cry1Ab Rice with Lepidopteran Pest Resistance by Agrobacterium Mixture-Mediated Co-transformation QI Yong-bin , YE Sheng-hai , LU Yan-ting , JIN Qing-sheng , ZHANG Xiao-ming 2009, 16(3): 181-186 .  DOI: 10.1016/S1672-6308(08)60077-3 Abstract ( )   PDF   Cry1Ab gene was transformed into four rice varieties, Zhejing 22, Zhejing 27, Jiahua 1 and Xiushui 63 mediated by Agrobacterium-mixture co-transformation. Rice genotype had an important effect on callus induction and transformation efficiency. Different mixtures of Agrobacterium strains (EHA105 and EHA101) contained Hpt and Cry1Ab genes resulted in different frequencies of resistant calli. There was no correlation between the frequency of transformants with the ratio of the Agrobacterium strain mixture contained Hpt and Cry1Ab genes. A total of 509 transgenic plants were obtained from the four rice varieties, and 272 T2 progenies were analyzed for Cry1Ab and Hpt genes. PCR analysis revealed that 412 regenerated plants were Hpt positive (80.94%), 62 plants were also Cry1Ab co-transformants (15.05% in total frequency), and 42 plants among the 272 T2 progenies were Cry1Ab positive but Hpt negative. This suggests that marker-free transgenic plants could be produced by co-transformation mediated by mixed Agrobacterium strains with the selectable marker gene and target gene. Southern blot analysis of five independent marker-free T2 transgenic lines co-transformed from Zhejing 22 showed that Cry1Ab gene had been inserted into rice genome with a single copy. The transgenic plants showed significantly stronger resistance to lepidopteron than the non-transgenic plants under no application of insecticides against lepidopteron.

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Temperature Stress at Grain Filling Stage Mediates Expression of Three Isoform Genes Encoding Starch Branching Enzymes in Rice Endosperm WEI Ke-su, CHENG Fang-min, ZHANG Qi-fang, LIU Kui-gang 2009, 16(3): 187-193 .  DOI: 10.1016/S1672-6308(08)60078-5 Abstract ( )   PDF   An early-maturity indica rice variety Zhefu 49, whose grain quality and starch structure are sensitive to environmental temperature, was subjected to different temperatures (32ºC for high temperature and 22ºC for optimum temperature) at the grain filling stage in plant growth chambers, and the different expressions of three isoform genes (SBEI, SBEIII and SBEIV) encoding starch branching enzyme (SBE) in the endosperms were studied by the real-time fluorescence quantitative PCR (FQ-PCR) method. Effects of high temperature on the SBE expression in developing rice endosperms were isoform-dependent. High temperature significantly down-regulated the expressions of SBEI and SBEIII, while up-regulated the expression of SBEIV. Compared with SBEIV and SBEIII, the expression of SBEI gene in Zhefu 49 rice endosperms was more sensitive to temperature variation at the grain filling stage. This study indicates that changes in weather/climate conditions especially temperature stress influence rice grain formation and its quality as evidenced by isoform expression.

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Breeding and Characterization of a New Rice Restorer Line Containing Bt Gene GAO Fang-yuan , LU Xian-jun , HE Shu-lin , CHEN Xiao-juan , LU Dai-hua , SUN Shu-xia , LI Zhi-hua , LIU Guang-chun , ZHANG Yi-zheng , REN Guang-jun , 2009, 16(3): 194-200 .  DOI: 10.1016/S1672-6308(08)60079-7 Abstract ( )   PDF   Bt5198, a new rice restorer line containing Bt gene, was developed from the cross and backcross of the elite restorer line Chenghui 177 with Bt Minghui 63, a transgenic Bt restorer line. The inbred lines were evaluated using PCR amplification, test paper evaluation, insect resistance evaluation in both the laboratory and paddy fields, nursery evaluation of rice blast resistance and pedigree selection of agronomic traits. Larval mortalities on Bt5198 and Bt Minghui 63 were 100% when rice culms were inoculated with the eggs of the striped stem borer (SSB) in the laboratory. Bt5198 was highly resistant against SSB and the yellow stem borer (YSB) under field conditions. The F1 hybrids derived from Bt5198 and four cytoplasmic male sterile (CMS) lines were also highly resistant to SSB and YSB and had a significant heterosis. Two-year evaluation of rice blast resistance confirmed that the resistance levels of Bt5198 to leaf blast and neck blast were similar to those of Chenghui 177 and significantly better than those of Bt Minghui 63. Seed germination ability and pollen yield of Bt5198 were similar with Chenghui 177, suggesting that the introduction of the Bt gene into the new restorer line had no significant effects on seed vitality or the yield of seed production. To identify the presence of the Bt gene, it was effective to combine test paper examination with the evaluation of insect-resistance, both in the laboratory and under field conditions.

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Effect of Cold-Water Irrigation on Grain Quality Traits in japonica Rice Varieties from Yunnan Province, China ZHAO Guo-zhen, LIU Ji-xin, YANG Sea-jun, YEA Jong-doo, LIAO Xin-hua, SU Zhen-xi, SHI Rong, JIANG Cong, DAI Lu-yuan 2009, 16(3): 201-209 .  DOI: 10.1016/S1672-6308(08)60080-3 Abstract ( )   PDF   The response of grain quality traits to cold-water irrigation and its correlation with cold tolerance were studied in 11 japonica rice varieties from Yunnan Province, China. The results indicated that the response of grain quality traits to the cold-water stress varied with rice varieties and grain quality traits. Under the cold-water stress, grain width, chalky rice rate, whiteness, 1000-grain weight, brown rice rate, taste meter value, peak viscosity, trough viscosity, breakdown viscosity and final viscosity significantly decreased, whereas grain length-width ratio, head rice rate, alkali digestion value, protein content and setback viscosity markedly increased. However, the other traits such as grain length, amylose content, milled rice rate, peak viscosity time and pasting temperature were not significantly affected by the cold-water stress. Significant correlations were discovered between phenotypic acceptability and cold response indices of taste meter value, protein content, peak viscosity and breakdown viscosity. Therefore, it would be very important to improve the cold tolerance of Yunnan rice varieties in order to stabilize and improve their eating quality.

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Effects of Ethephon on Aerenchyma Formation in Rice Roots KONG Yu, WANG Zhong, CHEN Juan, PAN Xue-tong, LIU Da-tong, ZHANG Er-jin 2009, 16(3): 210-216 .  DOI: 10.1016/S1672-6308(08)60081-5 Abstract ( )   PDF   The effects of ethephon on the constitutive aerenchyma formation in roots were studied with a rice variety Yangdao 6 as material. The number of air spaces formed by disintegrated cells in mediopellis increased significantly with the rising ethephon concentrations, whereas superoxide dismutase (SOD) activity showed downward trends. Compared with the control, the expression levels of xyloglucan endotransglycosylase (XET) gene were markedly higher both at the apical 10 mm and distal parts of roots in 100 mg/L ethephon treated plants. The accumulation of XET was supposed to be associated with the aerenchyma development. Furthermore, earlier cortical cell death was observed under the ethephon treatments, and most of nuclei of cells at 4 mm from the root apex disintegrated with many Golgi apparatus, mitochondria and membrane- bound vesicles around the cell wall.

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Simulation on Distribution of Photosynthetically Active Radiation in Canopy and Optimum Leaf Rolling Index in Rice with Rolling Leaves HU Ning, LU Chuan-gen, YAO Ke-min, ZOU Jiang-shi 2009, 16(3): 217-225 .  DOI: 10.1016/S1672-6308(08)60082-7 Abstract ( )   PDF   By replacing leaf area index (LAI) with effective leaf area index (ELAI) through introduction of leaf rolling index (LRI), the distributions of photosynthetically active radiation (PAR) in the canopies of three hybrid rice combinations, Liangyou E32 with high LRI, Liangyoupeijiu with moderate LRI and Shanyou 63 with non-rolling leaves (normal), were simulated. The model based on ELAI could predict more accurately than that based on LAI. The PAR interception, conversion and utilization efficiency in the three combinations were studied to evaluate their optimal LRI and LAI. The PAR utilization efficiency of Liangyou E32 was lower due to excessive rolling leaves and less ELAI, and that of Shanyou 63 was also lower because of the faulty PAR interception and lower photosynthetic rate and saturation point at lower layer in canopy. Compared with the above two combinations, Liangyoupeijiu showed more appropriate distribution of PAR interception and conversion efficiency in canopy, and higher PAR utilization efficiency. The optimal LRI and LAI for Liangyoupeijiu were 0.11 and 7.6, respectively, which were close to the observed value, 0.11 and 7.9, respectively. However, the optimum LAI was 9.8 for Liangyou E32 and 6.2 for Shanyou 63, larger or smaller than those under the current plant density, which led to lower efficiency of PAR utilization. Besides, the optimum LRI for Liangyou E32 and Shanyou 63 were 0.12 and 0.08, respectively, which were close to the actual LRI for Liangyoupeijiu (0.11).

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Chemical, Sensorial and Rheological Properties of a New Organic Rice Bran Beverage Gerson Luis FACCIN, Leila do Nascimento VIEIRA, Letícia Adélia MIOTTo, Pedro Luiz Manique BARRETO, Edna Regina AMANTE 2009, 16(3): 226-234 .  DOI: 10.1016/S1672-6308(08)60083-9 Abstract ( )   PDF   Rice bran is a solid residue from rice polishing that is used in animal nutrition and rice oil production. Cultivation conditions with agro-toxics, lipids instability, and tendency for mycotoxin contamination restrict its application in human nutrition. Therefore, organic agriculture is an alternative to use the properties of rice bran. Rice bran beverage is a new cereal product from organic rice. This work presents the preliminary results of the chemical and rheological studies of a bath pasteurized rice bran beverage. Compared with integral defatted milk, soy extracts, and brown rice low-fat milk, the rice bran beverage studied in this work presents itself as an important source of minerals and unsaturated lipids. All essential amino acids were found in this product. Glutamic and aspartic acids were predominant. Bath pasteurization at boiling water temperature for 15 and 30 min was adequate for microbiological safety. Refrigeration storage for 20 days, evaluated by pH and acidity variations, was ideal for assessment of the beverage conservation time. The beverage viscosity was of the Newtonian standard behavior, and its viscosity during storage was not a good parameter to evaluate shelf life. Sensory preference tests showed positive perspectives for this new beverage.

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Recent Advances in Development of Herbicide Resistant Transgenic Hybrid Rice in China XIAO Guo-ying 2009, 16(3): 235-239 .  DOI: 10.1016/S1672-6308(08)60084-0 Abstract ( )   PDF   In addition to weed control in direct seeding field of hybrid rice, herbicide resistance genes were used by Chinese scientists to increase and identify the purity of hybrid seeds, and to realize the mechanization of hybrid seed production. The elite restorer lines, such as Minghui 63, R752, T461, R402, D68 and E32 were transformed directly with herbicide resistance genes, in which D68 and E32 are restorer lines of two-line system and the others are of three-line system. Because almost all of important restorer lines are indica varieties and are recalcitrant in transformation, many herbicide resistant near-isogenic restorer lines were developed by sexual hybridization of indica and japonica varieties and backcross with indica restorer lines later, such as Ce 64, Minghui 63, Teqing, Milyang 46, R402 and 9311, in which 9311 is a restorer line of two-line system. The Pei'ai 64S, P88S, 4008S and 7001S, were transformed with herbicide resistance genes. A few herbicide resistant male sterile lines were developed through sexual hybridization and subsequently systemic selection, such as Bar1259S, Bar2172S, 05Z221A and 05Z227A. With the employment of herbicide resistant male sterile lines or herbicide resistant restorer lines, a few herbicide resistant hybrid rice combinations were developed, such as Xiang 125S/Bar 68-1 and Pei'ai 64S/Bar 9311. Based on herbicide resistance, the research was marching on to investigate the parental lines of hybrid rice with insect resistance, drought tolerance, etc.

Short Communication

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Biochemical Changes Associated with Germinating Rice Grains and Germination Improvement Subajiny VELUPPILLAI, Ketheeswary NITHYANANTHARAJAH, Seevaratnam VASANTHARUBA, Sandrasegarampillai BALAKUMAR, Vasanthy ARASARATNAM 2009, 16(3): 240-242 .  DOI: 10.1016/S1672-6308(08)60085-2 Abstract ( )   PDF   To determine biochemical changes during the germination of rice grains (Oryza sativa L. subsp. indica var. Mottaikaruppan) and to improve germination rate using gibberellic acid and surfactants [sodium dodecyl sulfate (SDS) (1.0 g/L) and Triton-X-100 (1.0 mL/L)], whole rice grains soaked in distilled water for 12 h at 30ºC were germinated in the dark at 30ºC for five days. The highest germination rate (77.1%) was obtained on the 5th day. An increase in the content of reducing sugars from 7.3 to 58.1 mg/g DM (dry matter) was observed from the 1st day of germination. Free amino acids and soluble protein contents increased to 3.69 and 5.29 mg/g DM, respectively on the 5th day of germination. Total protein content decreased from 100.5 to 91.0 g/kg DM during germination. Increases in amylolytic (1.1 to 190.0 U/g DM) and proteolytic (0 to 0.12 U/g DM) activities were observed during germination. Effects of different concentrations of gibberellic acid on the germination of rice grains were evaluated and 0.1 g/L was found to promote germination. When effects of gibberellic acid (0.1 g/L) and surfactants were evaluated individually and together, higher germination rate was observed in the control experiment (grains germinated in distilled water), whereas giberellic acid and surfactants decreased the germination rate. Therefore, the flour obtained from the grains germinated for four days using distilled water to obtain high content of soluble materials and enzyme activities can be used in preparation of bakery items.

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Effect of Stewing in Cooking Step on Textural and Morphological Properties of Cooked Rice E. GHASEMI, M. T. Hamed MOSAVIAN, M. H. Haddad KHODAPARAST 2009, 16(3): 243-246 .  DOI: 10.1016/S1672-6308(08)60086-4 Abstract ( )   PDF   Stewing of rice grains by steam after boiling in excess water can be used for cooking rice perfectly. The effects of this procedure in cooking of three varieties of Iranian rice (Sang Tarom, Domsiyah and Fajr) on textural and morphological properties of cooked rice grains were investigated. The results showed that this step in rice cooking reduced the hardness and increased the adhesiveness of rice grains significantly. By the use of the scanning electron microscopy, it was shown that the outer surface of cooked rice stewed by steam had less porosity and closer pores due to the modification during cooking, and better gelatinization and more expansion of starch granules compared to non-stewed samples. The use of this procedure in rice cooking to provide a fully cooked and gelatinized, softer and stickier final product is recommended.