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28 September 2006, Volume 13 Issue 3 Previous Issue    Next Issue
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Cloning and Expression Analysis of OsNADPH1 Gene from Rice in Drought Stress Response CHEN Jing, WAN Jia, JIANG Hua, GAO Xiao-ling, WANG Ping-rong, XI Jiang, XU Zheng-jun, 2006, 13(3): 149-154 .  Abstract ( )   PDF (314KB) ( )   An experiment was conducted to compare the mRNA expression difference in rice leaves and roots under drought stress and normal conditions using Fluorescent Differential Display (FDD) method. One positive fragment was isolated by combination of the H. A. Yellow-PAGE (contained 0.1% H. A. Yellow) separation and macroarray screening methods. Compared to Arabidopsis thaliana NADPH oxidoreductase gene, it has 96% identity. The cDNA was 1423 bp, and contained a complete open reading frame of 1048 bp encoding a protein with 345 amino acid residues. Moreover, the gene expression level was higher under drought stress than that under normal conditions. The possible role of NADPH oxidoreductase gene under drought response was also discussed.

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Genetic Diversity among Parents of Hybrid Rice Based on Cluster Analysis of Morphological Traits and Simple Sequence Repeat Markers WANG Sheng-jun, LU Zuo-mei, WAN Jian-min, 2006, 13(3): 155-160 .  Abstract ( )   PDF (59KB) ( )   The genetic diversity of 41 parental lines popularized in commercial hybrid rice production in China was studied by using cluster analysis of morphological traits and simple sequence repeat (SSR) markers. Forty-one entries were assigned into two clusters (i.e. early or medium-maturing cluster; medium or late-maturing cluster) and further assigned into six sub-clusters based on morphological trait cluster analysis. The early or medium-maturing cluster was composed of 15 maintainer lines, four early-maturing restorer lines and two thermo-sensitive genic male sterile lines, and the medium or late-maturing cluster included 16 restorer lines and 4 medium or late-maturing maintainer lines. Moreover, the SSR cluster analysis classified 41 entries into two groups (i.e. maintainer line group and restorer line group) and seven sub-groups. The maintainer line group consisted of all 19 maintainer lines, two thermo-sensitive genic male sterile lines, while the restorer line group was composed of all 20 restorer lines. The SSR analysis fitted better with the pedigree information. From the views on hybrid rice breeding, the results suggested that SSR analysis might be a better method to study the diversity of parental lines in indica hybrid rice.

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Identification of QTLs for Cooking and Eating Quality of Rice Grain SUN Shi-yong, HAO Wei, LIN Hong-xuan 2006, 13(3): 161-169 .  Abstract ( )   PDF (82KB) ( )   The BIL (backcross inbred line) population derived from the cross between Koshihikari (good eating and cooking quality, japonica) and Kasalath (poor quality, indica) was used to analyze the QTLs for amylose content (AC), gelatinization temperature (GT), gel consistency (GC) and protein content (PC). Eight main-effect QTLs including 2 for AC, 3 for GT, 2 for GC and 1 for PC were identified. Moreover, 27 epistatic QTL pairs including 7 for AC, 5 for GT, 4 for GC and 11 for PC were also detected while for AC and GT, one main-effect QTL with a major gene was detected, respectively. Therefore, the main-effect QTL might be more responsible for the current variation than the epistatic QTL. The result indicated that the main-effect QTL is the primary genetic basis for those traits. However, for PC, the epistatic QTL explained a much greater portion of the total variation than main-effect QTL, suggesting that epistatic loci are the primary genetic basis for such trait. In the experiment, chromosome segment substitution lines (CSSLs) were used to confirm reliabilities of the main effect QTLs detected in BIL population. Of the 8 main-effect QTLs for 4 traits in BIL analysis, 6 were confirmed and 2 remained unconfirmed by CSSLs analysis.

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Variations in Concentration and Distribution of Health-Related Elements Affected by Environmental and Genotypic Differences in Rice Grains REN Xue-liang, LIU Qing-long, WU Dian-xing, SHU Qing-yao 2006, 13(3): 170-178 .  Abstract ( )   PDF (67KB) ( )   A research work was conducted to investigate the variations in concentration and distribution of health-related elements affected by environmental and genotypic differences in rice grains. The grain of Xieqingzao B (indica rice variety) and Xiushui 110 (japonica rice variety) were divided into: hull, bran and milled rice, based on the conventional rice consumption and process. Xieqingzao B was grown at four different locations, and at one location, it was planted in the same field and season as Xiushui 110. In addition, another four indica and four japonica varieties were cultivated in the same field and time to analyze the elements in milled rice. The average concentrations of total P and phytic acid P were the highest in the bran, followed by milled rice and hull; Zn, K, Mg, and As concentrations were the highest in bran, followed by hull and milled rice, while Fe, Ca, and Cu concentrations were the highest in the hull, but similar in bran and milled rice. The result indicated that genotype and environment significantly affected the concentrations of all the tested elements, while the distribution of the above elements in grains was not in the same order as concentration. Moreover, all the elements except 97.7% of Cu and 93.2% of Fe was deposited in the hull on average, were mostly distributed either in the bran (37.3% and 57.7% for K and phytic acid P) or in milled rice (41.7%, 42.6%, 40.3%, 49.8% for Zn, Mg, As, total P, respectively).

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Effect of Dominant Semi-Dwarf Gene on Plant Height and Its Related Traits and Sensitivity to Gibberellic Acid in Rice LIU Bin-mei, CHENG Can, WU Yue-jin, TONG Ji-ping, WU Jin-hua, ZHANG Ying, YUAN Qin 2006, 13(3): 179-184 .  Abstract ( )   PDF (79KB) ( )   Six pairs of tall and dwarf near-isogenic lines derived from a dominant semi-dwarf mutant (Y98149) were selected to study height expression and sensitivity to gibberellic acid (GA3). The lengths of the 4-5th internode, the 3rd, 2nd, 1st internodes from the top and the panicle length in the six dwarf near isogenic lines were 97.2%, 53.3%, 65.1%, 61.9% and 94.7% of those in the six tall ones, respectively, indicating that the dominant semi-dwarfing gene significantly inhibited the internode elongation. Moreover, Y98149 (mutant type) was more sensitive to GA3 than Y98148 (wild type), and had a lower GA3 concentration in plant, about 78% of Y98148.

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Photosynthetic Characteristics and Heterosis in Transgenic Hybrid Rice with Maize Phosphoenolpyruvate Carboxylase (pepc) Gene LI Ji-hang, XIANG Xun-chao, ZHOU Hua-qiang, HE Li-bin, ZHANG Kai-zheng, LI Ping, 2006, 13(3): 185-192 .  Abstract ( )   PDF (97KB) ( )   Abstract: Three F1 hybrids derived from the sterile rice lines Gang 46A, 776A and 2480A and the improved restorer line Shuhui 881 containing maize phosphoenolpyruvate carboxylase (pepc) gene were used to analyze the effect of pepc gene on the heterosis and photosynthetic characteristics, while the F1 obtained by crossing Shuhui 881 with the above three sterile lines served as controls. The dynamics of photosynthetic characteristics in leaves of three F1 with pepc gene and their controls were determined at the initial-tillering, maxium-tillering, elongation, initial-heading, heading, maturity stages, and other different times after flag leaf fully expanded. The PEPCase activities of the three F1 with pepc gene increased significantly as compared with control plants during the whole developmental stages. Moreover, the net photosynthesis rate (Pn) also increased to certain extent. The data showed that PEPCase activity was significantly correlated to Pn with a correlation coefficient of 0.6081**. The photosynthetic indexes of the three F1 with pepc gene were obviously superior to respective controls in apparent quantum efficiency, light compensation point and carboxylation efficiency, while the CO2 compensation point was lower than that of corresponding control. The Pn of the three F1 with pepc gene at light saturation point and CO2 saturation point was also higher than that of control plants. In addition, the three F1 with pepc gene had an average increase of 37.10% in grain yields per plant in comparison with control plants. The results indicated that the photosynthetic characteristics of hybrid rice containing pepc gene had been improved to some extent due to the introduction of pepc gene.

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Comparison of Tissue Transglutaminase Activity During Young Panicle Development in Honglian-type Cytoplasmic Male Sterile Rice CHANG Xun, ZHANG Zai-jun, LI Yang-sheng, ZHU Ying-guo 2006, 13(3): 193-198 .  Abstract ( )   PDF (59KB) ( )   To investigate the changes of tissue transglutaminase activity, the leaves and young panicles of rice at different developmental stages were excised from the Honglian-type cytoplasmic male sterile line, Yuetai A and its maintainer line, Yuetai B, respectively. An ELISA measurement protocol for tissue transglutaminase activity detection in rice was well established. The results indicated that the tissue transglutaminase activity was regulated positively by calcium cation, and the tissue transglutaminase activity in senescent leaves was remarkably higher than that in young leaves. No distinct difference was noted between Yuetai A and Yuetai B. Moreover, from the tetrad to binucleate stages the tissue transglutaminase activity increased gradually with the progression of the young panicle development and up to maximum at binucleate stage in Yuetai A. However, no similar changes were observed in Yuetai B. This indicates that the tissue transglutaminase is involved in cell programmed death in abortive pollen.

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Effects of Nitrogen Fertilizer Treatments on Filling and Respiratory Rate of Caryopsis in Rice CHEN Juan, WANG Zhong, CHEN Gang, MO Yi-wei 2006, 13(3): 199-204 .  Abstract ( )   PDF (79KB) ( )     An experiment was conducted to study the effects of nitrogen (N) rate and application time on grain filling and respiratory trait of caryopsis in two rice varieties, IR36 and Dali. The treatments were consisted of no N application topdressing at both tillering and booting stages (CK), 6 g/pot of N topdressing at the tillering stage and 2 g/pot of N topdressing at the booting stage, 2 g/pot of N topdressing at the tillering stage and 6 g/pot of N topdressing at the booting stage. The results showed that the proper utilization of N fertilizer can be helpful to maintain the higher water content, higher respiratory rate and higher dehydrogenase activity of rice caryopsis in late filling phase, and prolong the course for filling and maintaining higher respiratory rate and dehydrogenase activity of rice caryopsis. More N application at booting was more effective compared to more N application at tillering.

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Effect of High Temperature on Sucrose Content and Sucrose Cleaving Enzyme Activity in Rice Grain During the Filling Stage LI Tian, LIU Qi-hua, Ryu OHSUGI , Tohru YAMAGISHI , Haruto SASAKI 2006, 13(3): 205-210 .  Abstract ( )   PDF (61KB) ( )   Dynamic changes of sucrose, fructose, glucose contents and differences in activities of sucrose synthase, vacuolar invertase, and cell wall bound invertase in rice grain after flowering stage were studied under natural and high temperatures by using two japonica rice varieties Koshihikari and Sasanishiki. In rice grains, the sucrose synthase activity was higher than that of invertase, which was significantly correlated with starch accumulation rate, indicating that the sucrose synthase played an important role in sucrose degradation and starch synthesis. Under high temperature, the significant increase in grain sucrose content without any increase in fructose and glucose contents, suggested that the high temperature treatment enhanced sucrose accumulation, while diminished sucrose degradation in rice grains. Compared with the control plants, the decrease in activities of sucrose synthase, vacuolar invertase, and cell wall bound invertase with high temperature treated plants indicated that the deceleration of sucrose-degradation was related to the decrease in activities of sucrose synthase and invertase.

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Specific Spikelet Fertility as an Indicator of Cold Tolerance Identification at Booting Stage in Rice XU Fu-rong, YU Teng-qiong, YAN Hong-mei, TANG Cui-feng, A Xin-xiang, DAI Lu-yuan 2006, 13(3): 211-217 .  Abstract ( )   PDF (79KB) ( )   By using the parents, Kunmingxiaobaigu, a landrace variety with cold tolerance from Yunnan, China, and Towada, a cold-sensitive variety bred in Japan, as well as their F8 and F9 RIL progenies as test materials, cold tolerance of rice at the booting stage in 2002 and 2003 under four different altitudes (environments), and the correlationship between spikelet fertility and specific spikelet fertility (spikelet fertility of nine spikelets from the 3rd to the 5th spikelets of three primary branches at the top of each panicle) of single plant were analyzed. The data revealed a significant correlationship between spikelet fertility and specific spikelet fertility with the range from 0.7364 to 0.9011. However, under the cold stress environments, the correlation coefficients were higher than those without cold stress. On the other hand, the panicle exsertion was correlated to both spikelet fertility and specific spikelet fertility. Moreover, the heredity analysis suggested that specific spikelet fertility could replace spikelet fertility as an identification indicator, while panicle exsertion could be used as a partial indicator of cold tolerance identification at the booting stage in rice.

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Biodiversity and Dynamics of Planthoppers and Their Natural Enemies in Rice Fields with Different Nitrogen Regimes LU Zhong-xian, S. VILLAREAL , YU Xiao-ping, K. L. HEONG , HU Cui 2006, 13(3): 218-226 .  Abstract ( )   PDF (85KB) ( )   A field experiment was conducted to study the effect of different nitrogen fertilizer rates i.e. 200, 100 and 0 kg N/ha in paddy fields at International Rice Research Institute, Manila, Philippines. Biodiversity of arthropods sampled by Blower-Vac, and dynamics of planthoppers, egg parasitoids of Homoptera trapped by rice plants with eggs of brown planthoppers (BPH) Nilaparvata lugens (Stål), and web spiders on rice canopy collected by sweeping net, were analyzed at different rice growth stages. The most abundant arthropods were sampled at the milking stage of rice, totalling 116 species identified into 14 insect orders and 15 species of spider in all samples. Meanwhile the number of arthropod species significantly increased with rice growth and the diversity indices increased with the increase of nitrogen rate at the booting stage. On the other hand, in the dominant predators, Pardosa pseudoannulata, Callitrichi formosana, Micraspis sp., Cyrtorhinus lividipennis, Veliidae sp. and Mesoveliidae sp., only C. lividipennis and Micraspis sp. were increased significantly in abundance following the application of nitrogen at the milking stage of rice. The egg parasitoids of plant-hoppers were predominated by Anagrus flaveolus and Oligosita sp. and their densities in the field without nitrogen fertilizer were markedly higher than those in fields with 100 and 200 kg N/ha at both booting and milking stages of rice. The number and web area of dominant residential spiders Tetragnatha sp. and Araneus sp. in rice canopy significantly reduced with the increase of nitrogen fertilizer. The population density of planthoppers, included BPH and the white-backed planthoppers (WBPH) Sogatella furcifera Horváth, peaked during the booting stage, however, the number of BPH in rice field with 200 kg N/ha was considerably higher than those in other two rice fields with 100 kg N/ha and 0 kg N/ha at the booting as well as the milking stage. These results indicated that the rapid growth in populations of planthopper due to excessive nitrogen might be attributed to the combination of reduction in control capacity of natural enemies and strong simulation of nitrogen to planthoppers.