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    Research Paper
    Cloning and Expression Analysis of an AP2/ERF Gene and Its Responses to Phytohormones and Abiotic Stresses in Rice
    MA Hao-li, ZHOU Han-lin, ZHANG Huai-yu, ZHAO Jie
    2010, 17(1): 1-9 .  DOI: 10.1016/S1672-6308(08)60098-0
    Abstract ( )   PDF  
    Ethylene response factors (ERFs) play important roles in response to plant biotic and abiotic stresses. In this study, a gene encoding a putative AP2/ERF domain-containing protein was isolated by screening a SSH cDNA library from rice and designated as Oryza sativa AP2/ERF-like protein (OsAP2LP) gene. OsAP2LP is 1491 bp in length, interrupted by seven introns, and encodes a putative protein of 348 amino acids. Temporal and spatial expression analysis showed that the OsAP2LP gene was preferentially expressed in roots, panicles, mature embryos and seeds in rice. Real-time quantitative PCR analysis indicated that the expression levels of the OsAP2LP gene were increased under the treatments of drought and gibberellin but decreased under the treatments of low temperature, salt, abscisic acid (ABA) and zeatin. Taken together, these results suggest that OsAP2LP might be involved in stress responses, and probably plays roles as a transcription regulator when plants response to cold, salt and drought stresses through ABA and gibberellin pathways.
    Preliminary Study on Function of Calcineurin B-Like Protein Gene OsCBL8 in Rice
    MA Bo-jun, GU Zhi-min, TANG Hai-juan, CHEN Xi-feng, LIU Feng, ZHANG Hong-sheng
    2010, 17(1): 10-18 .  DOI: 10.1016/S1672-6308(08)60099-2
    Abstract ( )   PDF  
    The homozygous T3 transgenic lines with sense OsCBL8 gene and antisense OsCBL8 gene obtained by agro-transformation were used to investigate the function of OsCBL8 in rice. Semi-quantitative RT-PCR showed that the expression of OsCBL8 extremely increased in sense transgenic lines, and decreased to some extents in antisense transgenic lines. Such up- and down-regulation of the OsCBL8 gene in these transgenic lines had little effects on main agronomic traits, but significantly decreased the number of filled grains per panicle and seed setting rate in some of transgenic lines. By evaluation of the tolerance to 150 mmol/L NaCl, 20% PEG6000 and low temperature treatments, and relevant physiological indices, 8F12, a sense transgenic line with high salt tolerance, and 8R14, an antisense transgenic line with high drought tolerance, were obtained, which suggests that the OsCBL8 gene is involved in the response of rice to abiotic stresses.
    Genetic Transformation of Rice with Pi-d2 Gene Enhances Resistance to Rice Blast Fungus Magnaporthe oryzae
    CHEN De-xi, CHEN Xue-wei, MA Bing-tian, WANG Yu-ping, ZHU Li-huang, LI Shi-gui,
    2010, 17(1): 19-27 .  DOI: 10.1016/S1672-6308(08)60100-6
    Abstract ( )   PDF  
    The gene Pi-d2, conferring gene-for-gene resistance to the Chinese blast strain ZB15, was isolated from a rice variety (Digu) by the map-based cloning strategy. Here, we constructed a control plasmid pZH01-pi-d2tp309 (pZH01-tp309) and three different expression constructs, pCB-Pi-d25.3kb (pCB5.3kb), pCB-Pi-d26.3kb (pCB6.3kb) and pZH01-Pi-d22.72kb (pZH01-2.72kb) of Pi-d2, driven by Pi-d2 gene’s own promoter or CaMV35S promoter. These constructs were separately introduced into japonica rice varieties Lijiangxintuanhegu, Taipei 309, Nipponbare and Zhonghua 9 through Agrobacterium- mediated transformation. A total of 150 transgenic rice plants were obtained from the regenerated calli selected on hygromycin. PCR, RT-PCR and Southern-blotting assay showed that the gene of interest had been integrated into rice genome and stably inherited. Thirty-five transgenic lines independently derived from T1 progeny were inoculated with the rice blast strain ZB15. Transformants exhibited resistance to rice blast at various levels. The lesions on the transgenic plant leaves were less severe than those on the controls and the resistance level of transgenic plants harboring the gene of interest from three vectors had no difference. The own promoter of Pi-d2, about 2.2 kb or 3.2 kb, had the similar promoter function as CaMV35S. Field evaluation for three successive years supported the results of artificial trial, and some lines with high resistance to rice leaf blast and neck blast were obtained.
    Construction of SSR Linkage Map and Analysis of QTLs for Rolled Leaf in Japonica Rice
    GUO Yuan, CHENG Bao-shan, HONG De-lin
    2010, 17(1): 28-34 .  DOI: 10.1016/S1672-6308(08)60101-8
    Abstract ( )   PDF  
    Genetic analysis of rolled leaf is important to rice ideotype breeding. To detect loci controlling rolled leaf of japonica restorer lines, SSR marker genotypes and phenotypes of flag leaf rolling index (LRI) were investigated in Xiushui 79 (P1, a japonica rice variety), C Bao (P2, a japonica restorer line) and 254 recombinant inbred lines derived from the cross between P1 and P2 , and in two environments. A genetic map of this cross was constructed, QTLs for LRI were detected and their interactions with environments were analyzed. Among 818 pairs of SSR primers, 90 primers showed polymorphism between P1 and P2, and 12 markers showed highly significant correlation with LRI in both environments based on single marker regression analysis. The genetic map containing 74 information loci has a total distance of 744.6 cM, with an average of 10.1 cM between two adjacent loci. Three QTLs (qRL-1, qRL-7 and qRL-8-1) were detected with two softwares: WinQTLCart 2.5 and QTLNetwork2.0. qRL-8-1 was a new locus, accounting for 15.5% and 12.8% of phenotypic variations in the two environments, respectively. The phenotypic variation explained by additive effect was 6.6%. No interaction was found between qRL-8-1 genotype and environments.
    Diversity Analysis in Selected Non-basmati Scented Rice Collection
    Sarika MATHURE, Narendra JAWALI, Altafhusain NADAF
    2010, 17(1): 35-42 .  DOI: 10.1016/S1672-6308(08)60102-X
    Abstract ( )   PDF  
    Diversity analysis among 23 rice varieties including 16 non-basmati scented accessions, 5 basmati accessions and 2 non-scented accessions was performed by random amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR) marker systems. The varieties analyzed by 11 RAPD and 8 ISSR primers yielded an average of 65% and 80% polymorphism, respectively. The average number of polymorphic bands generated per RAPD primer was 6 and per ISSR primer was 5.87. RAPD and ISSR data analysis individually could not segregate basmati and non-basmati scented rice accessions. However, the analysis using a combined data could group basmati and non-basmati scented rice accessions separately. The bands present specifically among three accessions of non-basmati scented rice were also identified. The study revealed a high genetic diversity among non-basmati scented rice accessions.
    Relationship Between Plant Type and Grain Quality of Japonica Hybrid Rice in Northern China
    HAO Xian-bin, MA Xiu-fang, HU Pei-song, ZHANG Zhong-xu, SUI Guo-min, HUA Ze-tian
    2010, 17(1): 43-50 .  DOI: 10.1016/S1672-6308(08)60103-1
    Abstract ( )   PDF  
    Plant type and grain quality are two major aspects in rice breeding. Using canonical correlation analysis and canonical redundancy analysis, the relationship between plant type traits and rice grain quality traits was studied with 100 crosses derived from 10 sterile lines × 10 restorer lines. There was a complex relationship between parts of the traits of the two aspects. The angle of the 2nd leaf from the top and single panicle weight played important roles in plant type system and amylose content and grain length in grain quality system. The angle of the 2nd leaf from the top, plant height and single panicle weight had a great effect on grain quality traits, and amylose content, brown rice rate and translucency were easily influenced by plant type traits. Selection index model indicated that japonica hybrid rice in Northern China with good quality was characterized by broad flag leaf and 2nd leaf from the top, narrow and short 3rd leaf from the top, low plant height, short culm, long and more panicles and low single panicle weight.
    Optimization of Bread Preparation from Wheat Flour and Malted Rice Flour
    Subajiny VELUPPILLAI, Ketheeswary NITHYANANTHARAJAH, Seevaratnam VASANTHARUBA, Sandrasegarampillai BALAKUMAR, Vasanthy ARASARATNAM
    2010, 17(1): 51-59 .  DOI: 10.1016/S1672-6308(08)60104-3
    Abstract ( )   PDF  
    The feasibility of partially replacing wheat flour with malted rice flour in bread making was evaluated in several formulations, aiming to find a formulation for the production of malted rice-wheat bread with better nutritional quality and consumer acceptance. The whole grains of a local rice variety (Oryza sativa L. subsp. indica var. Mottaikaruppan) were steeped in distilled water (12 h, 30°C) and germinated for 3 days to obtain high content of soluble materials and amylase activity in bread making. The quality of bread was evaluated by considering the physical and sensorial parameters. When the wheat flour was substituted with malted rice flour, 35% substitution level and the malted rice flour from 3 days of germination was the best according to the physical and sensory qualities of bread. The quality of bread was improved by the addition of 20 g of margarine, 20 g of baking powder and 20 g of yeast in 1 kg of flour. Among different ratios of yeast and baking powder, 2:1 was the best. Bread improver containing amylases and oxidizing agents at the concentration of 40 g/kg was selected as the best concentration. When comparing the final formulation made in the bakery with wheat bread, malted rice-wheat bread contains more soluble dietary fiber (0.62%), insoluble dietary fiber (3.95%), total dietary fiber (4.57%) and free amino acid content (0.64 g/kg) than those in wheat bread (0.5%, 2.73%, 3.23% and 0.36 g/kg, respectively).
    Review or Special Topic
    Research Progress on Functional Analysis of Rice WRKY Genes
    SONG Yu, AI Chong-rui, JING Shao-juan, YU Di-qiu
    2010, 17(1): 60-72 .  DOI: 10.1016/S1672-6308(08)60105-5
    Abstract ( )   PDF  
    Rice is a model plant for genomic study of grass species. Functional identification and definition of rice genes becomes the object of its functional genomics research. WRKY gene superfamily, one of the transcription factor gene families, was recently suggested to play important roles in plant development and stress response. In rice, the results of analyses of expression pattern and ectopic overexpressor lines also support this viewpoint, and the evidences implicate rice WRKY proteins in transcriptional reprogramming during biotic or abiotic stresses, senescence, sugar metabolites, and morphological architecture. In this paper, we review the advance in study of rice WRKY gene family and also propose unified nomenclature for rice WRKY factors to eliminate confusion.
    Short Communication
    Application of Functional Markers to Identify Genes for Bacterial Blight Resistance in Oryza rufipogon
    XIA Zhi-hui, HAN Fei, GAO Li-fen, YUAN Qian-hua, ZHAI Wen-xue, LIU Di, LUO Yue-hua
    2010, 17(1): 73-76 .  DOI: 10.1016/S1672-6308(08)60106-7
    Abstract ( )   PDF  
    Field resistances of nine accessions of common wild rice (Oryza rufipogon Griff.) and one rice variety (IR24) were evaluated by using nine strains of bacterial blight pathogen (Xanthomonas oryzae pv. oryzae) from the Philippines. IR24 was highly susceptible to all the strains, and six common wild rice accessions resisted all the nine strains, with a resistance frequency of 67%. The accessions Yulin and Wanning were only susceptible to PXO280 and PXO71, respectively. The accession Gaozhou was susceptible to the three strains PXO79, PXO99 and PXO339, whereas resistant to the other six strains. It could be concluded that there is at least one resistance gene in each common wild rice accession. The functional markers of the genes xa5, xa13, Xa21 and Xa27 were used to detect the presence of these resistance genes in the nine tested wild rice accessions, and it was found that four wild rice accessions contained heterozygous xa13. Among the nine common wild rice accessions, five were homozygous for Xa27 and three homozygous for xa27, and the accession Laibin contained neither xa27 nor Xa27. In addition, there were no xa5 and Xa21 in all of these accessions.
    Evaluation on Sixty-eight Rice Germplasms in Cold Tolerance at Germination Stage
    Peyman SHARIFI
    2010, 17(1): 77-81 .  DOI: 10.1016/S1672-6308(08)60107-9
    Abstract ( )   PDF  
    Sixty-eight rice germplasms were used for cold tolerance evaluation at the germination stage in laboratory. Seeds of rice germplasms germinated at three different temperatures containing low temperature (constant 13°C for 28 days), alternative temperature (a temperature cycle of 12 h at 20°C and 12 h at 23°C for 14 days) and control (constant 26°C for 7 days). Analysis of variance revealed that temperature had a significant effect on germination rate, coleoptile length and radicle length. Germination rate was strongly affected by the low temperature and alternative treatments. Stress of low temperature at the germination stage on the tested rice germplasms caused a reduction in final germination rate and the lengths of coleoptile and radicle. The normal and healthy seeds began to germinate within 36 h after imbibition and germination were completed on the 7th day in the control, but delayed under the low and alternative temperature treatments. The low and alternative temperature treatments delayed the growth of coleoptile and radicle compared to the control, and the average lengths of coleoptile and radicule were strongly inhibited with the decreasing temperature in all of the tested germplasms. Taichung, a semi-dwarf, low amylose content and early maturing rice variety, showed a significantly higher germination rate at the three temperature treatments and its coleoptile length was significantly higher than other germplasms.
    Comparison of Morphological and Genetic Differentiations in Filial Generation of Cross Between Indica and Japonica Rice
    MAO Ting, XU Hai, XU Quan, GUO Yan-hua, ZHU Chun-jie, CHEN Kai, WANG Jia-yu, XU Zheng-jin
    2010, 17(1): 82-86 .  DOI: 10.1016/S1672-6308(08)60108-0
    Abstract ( )   PDF  
    A recombinant inbred line (RIL) population of F8 and F9 generations derived from a cross between a typical indica rice (Qishanzhan) and a typical japonica rice (Akihikari) was used to study the difference between morphological differentiation based on phenotype characters and genetic differentiation using indica and japonica specific SSR markers, and to evaluate the relationship between vascular bundle characters and morphological and genetic differentiations. The results showed that the frequency distributions of morphological and genetic differentiations were all inclined to japonica type in the filial generation. The population was more inclined to japonica type based on genetic differentiation than on morphological differentiation. The consistent degrees of classification based on the Cheng’s index, the ratio of large vascular bundle number to small vascular bundle number in panicle neck (RLSVB) and the ratio of large vascular bundle number in the second internode from the top to that in the panicle neck (RLVB) were all about 50% compared with the genetic differentiation, and the consistent degree of the total scores of the Cheng’s index combined with the vascular bundle number ratios was significantly increased to about 80% compared with the genetic differentiation. Therefore, the vascular bundle characters could be used as a helpful supplement for subspecies classification.