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10 January 2014, Volume 28 Issue 1 Previous Issue    Next Issue
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Roles of OsPT6 on the Phosphate Uptake and Utilization in the Rice Seeding of Wuyujing 7 ZHANG Fang#, AI Hao#, WANG Danfeng, CAO Yue, SHI Shulin, GU Mian, SUN Shubin*, XU Guohua 2014, 28(1): 1-8.  DOI: 10.3969/j.issn.1001-7216.2014.01.001 Abstract ( )   PDF (3105KB) ( )   As one of members of the Pht1 transporters family in rice,the phosphate transporter OsPT6 plays a broad role in Pi uptake, translocation and internal transport throughout the plant. With the OsPT6 overexpressed transgenic rice of  Wuyujing 7, a highyielding variety, we studied the roles of OsPT6 on the phosphate uptake and utilization in rice. The main results are the following: 1)OsPT6 is abundantly expressed in roots of Wuyujing 7. Furthermore, the expression levels of OsPT6 in shoots and roots are induced by phosphate deficiency. 2)The overexpression of OsPT6 can promote the growth of plants.  The dry weight of shoots and roots of the  OsPT6 overexpressed transgenic plants was significantly increased, in both sufficient and deficientPi conditions for 35 days. 3)The total P concentration increases in different tissues and organs of OsPT6 overexpressed transgenic plants, especially in vegetable organs, at different Pisupply levels.

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Cloning and Expression Analysis of UvHog1 Gene in  Ustilaginoidea virens RAO Yuchun1,2,#, DING Zhengzhong1,3,#, CHEN Xifeng1, ZENG Dali2, MA Bojun1, GU Zhimin1,* 2014, 28(1): 9-14.  DOI: 10.3969/j.issn.1001-7216.2014.01.002 Abstract ( )   PDF (1381KB) ( )   Rice false smut, caused by Ustilaginoidea virens,  is an important disease in rice panicle. Degenerate PCR primers were designed according to the conserved amino acid sequence of several filamentous fungus mitogen activated protein kinase(MAPK) homologous to yeast Hog1 MAPK, and partial DNA fragment encoding a MAPK was amplified from U. virens through PCR. Then, a whole DNA sequence encoding the MAPK, designated as UvHog1, was obtained from U. virens by extending upstream and downstream sequence of the amplified fragment using RACE method. And its amino acid sequence shared 95%, 93%, 88% and 81% identity to MgOsm1 （AAF09475.1） from Magnaporthe grisea,  BbHog1 （AAS77871.1） from Beauveria bassiana,  AfOsm1（XP752664.1）from Aspergillus fumigatus and CrHog1（AAM26267.1）from Cryptococcus neoformans var. neoformans, respectively. Phylogenetic clustering suggested that UvHog1 is homologous to yeast Hog1 MAPK. The results of the decreased transcript levels of UvHog1 by salinity suggest that UvHog1 may be involved in the specifically responses to salt stresses.

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Generation of  Glyphosateresistant Transgenic Rice   Harboring Single Copy of 2mG2epsps Gene  by Clean DNA Transformation ZHAO Yan*, DEND Chunquan, DENG Lidie 2014, 28(1): 15-22.  DOI: 10.3969/j.issn.1001-7216.2014.01.003 Abstract ( )   PDF (1336KB) ( )   Clean DNA transformation is the technology of introducing exotic gene expression cassette into plant genome via particle bombardment, which can eliminate the disadvantageous impact of vector backbone sequence on transgenic plant fundamentally. Gene  2mG2epsps is an important glyphosate herbicide resistance gene with important breeding value. The effect of glyphosate on rice callus growth and differentiation was studied using japonica rice Nipponbare as material, and 2mG2epsps gene cassette was transformed into rice by clean DNA transformation. Results showed:  1) The growth and differentiation of rice callus can be notably inhibited by glyphosate. The regeneration frequency of green plantlet decreased significantly to 18.97%, comparing with that of the control 71.67%,  at  2 mmol/L glyphosate;  2) During rice transformation with  2mG2epsps gene expression cassette via particle bombardment, removal of the screening agent from regeneration medium is beneficial to the differentiation of the glyphosateresistant calli, which were screened out under glyphosate selection with transformation frequency  at 17.20%. Southern blot analysis revealed that the 2mG2epsps gene cassette was all integrated into rice genome in single copy and 52.17%（12/23)transgenic lines can render 12-50 mmol/L glyphosate. The present research provided the foundation for breeding appliance of the glyphosate resistant transgenic rices.

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Analysis of Expression Characters of Soluble Starch Synthase and Isoform Genes Involved in japonica Hybrid Progeny QU Ying, JIN Zhengxun*, LIU Haiying, XU Zhenhua, ZHU Linan, ZHENG Guanlong, ZHU Fangxu, 2014, 28(1): 23-31.  DOI: 10.3969/j.issn.1001-7216.2014.01.004 Abstract ( )   PDF (1314KB) ( )   Using  amylose  content as the selection indicator, we chose the progenies with significantly different amylose content in grains by continuous and unidirectional orthoselection from F2 to F10 generations, compared the progeny of Dongnong 1006（Its grain amylose content was 18.82%）and Dongnong 1012（7.70%）with their parent Dongnong 423（18.33%）and Toukei 180（11.05%）, respectively. And we also compared the progeny of Dongnong 1006（18.82%）and Dongnong 1012（7.70%）with their parent Xixuan 1（18.74%）and Tong 769（17.05%）. Moreover, all groups above were chosen to analyze amylose accumulation and soluble starch synthase(SSS) activity and the expression levels of isoform genes during the grain filling. The results showed that the accumulated amount of amylose in parents and hybrid progeny with high amylose contents were always higher than that in the low amylose content progenies in different periods of grain filling, but for the amylopectin content, there were opposite results in the maturity stage. There were no significant negative correlations between the grain amylose content and amylopectin content 10, 17, 24 days after heading, and the correlation coefficients between SSS activity and the grain amylose content were 0.8115**, -07554*, -0.5957, respectively. In addition, the correlation coefficients between SSS activity and amylopectin content were -0.0694, 0.5453, -0.0207, respectively. The expression levels of the OsSSSⅠ,OsSSSⅡ1, OsSSSⅡ3, OsSSSⅢ1 and  OsSSSⅢ2genes in endosperm of parents and hybrid progenies gradually peaked and then gradually declined, following a single peak curve along with the process of grain filling, while the expression levels of the OsSSSⅣ2  gene just showed a downdraft. However, the expression levels of the OsSSSⅢ2  and  OsSSSⅣ2  genes were higher than others in various periods of grain filling. Compared with their parents, hybrid progeny with high amylose content have the expression of increased genes and reducing genes during the different period of filling, as well as the hybrid progeny with low amylose content compared with their parents. Moreover, there was significantly positive correlation between SSS activity and the expression levels of the OsSSSⅠ,OsSSSⅡ3,OsSSSⅢ2,and no significant positive correlation between SSS activity and the expression of the OsSSSⅡ1  and  OsSSSⅣ2, and no significant negative correlation between SSS activity and the expression of the  OsSSSⅢ1.

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Changes in DNA Methylation Pattern in a Watersaving and Droughtresistance  Rice Variety at Threeleaf and Fourleaf stages after Drought Domestication ZHENG Xiaoguo1,2,#, CHEN Liang1,#, LOU Qiaojun1, XIA Hui1, LI Mingshou1, LUO Lijun1,2,* 2014, 28(1): 32-40.  DOI: 10.3969/j.issn.1001-7216.2014.01.005 Abstract ( )   PDF (1408KB) ( )   A watersaving and droughtresistance  rice Huhan 3 was grown under drought stress for  six successive generations after transplanting in the field. The variations in DNA methylation pattern between the original generation (G0) and the sixth generation (G6) were analyzed by methylation sensitive amplification polymorphism (MSAP) method. The results revealed that the methylated loci accounted for about 34% of the total. Among these, about 84% were fullmethylated loci and about 16% were hemimethylated ones. The DNA methylation level decreased from the threeleaf stage to the fourleaf stage in Huhan 3. Differentially methylated loci (DML) between generations or/and between different developmental stages accounted for 4.0% of the total, most of which were only related to plant development(579%). Compared to G0, the DNA methylation pattern of G6 changed after drought domestication, at threeleaf stage,  demethylated events occupying 59.1%, while at fourleaf stage, remethylated events occupied 47.9%. Genomewide alternations of DNA methylation were observed  along with rice growth and development, and DML mainly occurred on the gene′s promoter and exon region. The genes with DML were involved in a wide range of functions and participated in many important biological processes.

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Genetic Analysis and Position Cloning of a yellowgreen leaf 10 (ygl10) Gene, Responsible for Leaf Color in Rice YANG Hailian#, LIU Min#, GUO Min, LI Rongde, ZHANG Honggen, YAN Changjie* 2014, 28(1): 41-48.  DOI: 10.3969/j.issn.1001-7216.2014.01.006 Abstract ( )   PDF (2311KB) ( )   A rice mutant characterized by yellowgreen leaves (named as ygl10) was obtained from an indica cultivar 9311 via radiation of 60Coγ ray. Morphological analysis showed that, the ygl10 mutant exhibited shorter plant height and panicle length, decreased seed setting rate compared to its wild type (9311). Moreover, the chlorophyll content in the ygl10 mutant leaves dramatically decreased, especially for chlorophyll b content, being only about 2% of that in  its wild type. In addition, the SEM results showed that the numbers of grana lamella, and thylakoids in the mutant were less than those in the wild type. Genetic analysis and gene mapping showed that the yellow green leaf mutant was controlled by a single recessive gene, which  was located  in a 380 kb region on chromosome 10. We further analyzed the putative candidate open reading frames in the target region through sequencing, and the results showed that there was a 5nucleotide deletion in the ninth exon of CAO1 gene (encoding chlorophyll a  oxygenase involved in the biosynthesis of chlorophyll b), resulting in the frame shift to generate a new premature stop codon. Therefore, it is deduced that CAO1 is the candidate of ygl10.

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Senescent Characteristics of Flag Leaf Photosynthesis in a White Stripe Rice Mutant 6001 ZHEN Xiaohui1，SHEN Weijun 1，ZHANG Xiaojuan1，XU Jingang1，ZHANG Qijun2，LU Chuangen2，CHEN Guoxiang1,3，*， GAO Zhiping1,* 2014, 28(1): 49-56.  DOI: 10.3969/j.issn.1001-7216.2014.01.007 Abstract ( )   PDF (1882KB) ( )   The photosynthetic performance of flag leaf in a white stripe rice mutant 6001, was analyzed by combing physiological, biochemical and electron ultramicroscope techniques during the aging process. The results of physiological and biochemical analyses showed that as compared to the wild type 6028, the chlorophyll content  in mutant was 34.78%, 3.00% lower in heading and milkripe stages, respectively, but higher in full ripening stage. Net photosynthetic rate was also lower in heading stage, but declined more slowly with aging, especially at the later period of aging. Ca2+ ATPase/Mg2+ATPase enzyme activities and photophosphorylation activity also show a same trend. Only 68 kDa peptide component in the thylakoid membrane was changed significantly with aging，the change in the peptide component content might involved in the photosynthesis changes. The observation results with  the electron ultramicroscope showed that, the mutant had  more intact chloroplast, and the chloroplast membrane disintegrated more slowly in the process of aging. In conclusion, the slowdown of the photosynthetic senescence in the aging process suggested mutant 6001 performed a antiaging properties.

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Concentration  and Accumulation of Lead in Different Organs of Hybrid Rice CHEN Xinhong1,*, YE Yuxiu1, PAN Guoqing1, ZHAO Buhong2, YANG Jianchang3 2014, 28(1): 57-64.  DOI: 10.3969/j.issn.1001-7216.2014.01.008 Abstract ( )   PDF (413KB) ( )   The concentration and accumulation of Pb in different rice plant organs were measured in a potculture experiment at soil lead concentrations of 0 mg/kg(CK) and 500 mg/kg with six hybrid rice as materials. The results showed that Pb addition significantly reduced the grain yield of Liangyoupeijiu, 103S/Zhengjing 2, Fengyouxiangzhan and Shanyou 63 due to the reduction of spikelet number per panicle. There was no significant effect on grain yield for other hybrid rice combinations. Significant differences in uptake and accumulation of Pb were observed among the six combinations, with 103S/Zhengjing 2 and Liangyoupeijiu having the highest and K you 818 the lowest Pb accumulation in plants. Concentration or accumulation of Pb in various plant organs followed the order of root> culm and sheath> leaf, and Pb concentration in grains followed the order of bran> hull>milled rice. Pb in milled rice accounted for 25% of the total amount of Pb accumulated in grains. The concentration and accumulation of Pb in the same organ at heading and maturity stages were positively and significantly correlated, but the correlation was not significant between different organs. Among the six hybrids, Yangliangyou 6 contained the highest, and K you 818 the lowest Pb concentration in milled rice. The reasons for variations of Pb concentration and accumulation in plants among the hybrids were also discussed.

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Effects of Drought  Stress on Photosynthesis and Water Status of Rice Leaves DING Lei1, LI Yingrui1, LI Yong2, SHEN Qirong1, GUO Shiwei1,* 2014, 28(1): 65-70.  DOI: 10.3969/j.issn.1001-7216.2014.01.009 Abstract ( )   PDF (810KB) ( )   Hydroponic experiments were conducted to compare photosynthesis and water status in rice leaves under normal conditions and drought stress  simulated by addition of 10%, 20% and 30% polyethylene glycol (PEG6000). The results were listed as follows: 1) under  drought  stress, leaf photosynthesis, stomatal conductance, mesophyll conductance, total conductance, and chloroplastic CO2 concentration were decreased; 2)there was no significant difference in nonstomatal limitation under  drought   stress  and normal conditions. But compared with normal conditions, stomatal limitation under 30% PEG simulated drought  stress in Yangdao 6 and Shanyou 63 were increased by 42% and 81%, respectively; 3) there were positive relationships between photosynthesis and stomatal conductance, mesophyll conductance, total conductance and chloroplastic CO2 concentration; 4) under severe drought stress (20% and 30%), leaf water potential and water content were decreased significantly. And leaf water potential   was positively correlated with stomatal conductance, mesophyll conductance and total conductance. Therefore,  reduced  chloroplastic CO2 concentration  resulted from stomatal closure was the major limitation of photosynthesis. And the decreased leaf water potential may increase the internal CO2 transport resistance.

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Exogenous Silicon Alleviates Spikelet Fertility Reduction of Hybrid Rice Induced by High Temperature under Field Conditions WU Chenyang1, YAO Yimin1, SHAO Ping1, WANG Yi1, WANG Zhiwei1, TIAN Xiaohai1,2,* 2014, 28(1): 71-77.  DOI: 10.3969/j.issn.1001-7216.2014.01.010 Abstract ( )   PDF (657KB) ( )   Effects of exogenous silicon on spikelet fertility of hybrid rice were investigated  at natural high and normal temperatures during anthesis under field conditions with two hybrids, hightemperature sensitive Jinyou 63  and   hightemperature tolerant Shanyou 63 as material. The exogenous silicon via fertilizer application, in the form of sodium silicon (Na2SiO3·9H2O), was consecutively spayed for  three times at jointing stage at four concentrations,  0 mmol/L (TCK), 1.25 mmol/L(T1.25 ), 2.50 mmol/L (T2.50), and 3.75 mmol/L(T3.75 ). Varietal responses in terms of pollination properties, anther dehiscence and spikelet pollination  rate were examined to establish a feasible screening scheme of the most appropriate sodium silicate application level in rice management practices. Results showed that, sodium silicate applications at the concentration of 1.25 mmol/L, 2.50 mmol/L or 3.75 mmol/L under high temperature in field environments effectively increased the germinated pollen number  per stigma by 16.9% and 39.6% for the heatsensitive Jinyou 63 and heattolerant Shanyou 63, respectively. The number of   pollen grains per stigma increased by 34%  and 305%,  respectively.  The   pollen  germination  rate   rose by 11.3 and 7.0 percentage points, respectively; the percentage of florets with more than 10 germinated pollen grains was increased by 9.3  and 27.6 percentage points,  respectively; while the percentage of florets with fewer than 20  pollen grains  was reduced by 18.8  and 8.1 percentage points,  respectively. Application of the silicon fertilizer also increased anther basal dehiscence width by relative values of 19.0% and 10.3%, respectively, while it improved spikelet pollination rate by absolute values of 10.6 and 4.7 percentage points in the sensitive and tolerant hybrids, respectively. These results showed that the effect of silicon in alleviating fertility reduction may be mainly  attributed to  the pollen quality improvement, but not the pollen quantity or the anther dehiscence. Exogenous silicon   was more effective for hightemperature sensitive  combination  than that for the tolerant and the most effective dosage was at the concentration of 2.50 mmol/L.

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Occurence of Heterodera elachista in Guangxi Region and Its Intraspecies Heterogeneity  in rDNAITS Region ZHUO Kan1, SONG Handa1, WANG Honghong1, TAO Ye1, ZHANG Hongling1, LU Xiuhong2, HUANG Jinling2, LIU Zhiming2, LIAO Jinling1,* 2014, 28(1): 78-84.  DOI: 10.3969/j.issn.1001-7216.2014.01.011 Abstract ( )   PDF (1341KB) ( )   In 2011, a cyst nematode was isolated from rice roots and soils in Longsheng Terrace of Guangxi Region, China. Morphological characteristics of the cyst nematode were consistent with previous descriptions of Heterodera elachista. The rDNAITS sequences of the cyst nematode and H. elachista in GenBank shared 97.7%-99.3% identities. The phylogenetic tree based on rDNAITS showed that the cyst nematode was in the same monophyletic clade as H. elachista with 100% support and short branch differences. The results indicated the cyst nematode was Heterodera elachista. The restriction enzyme cutting sites of ten rDNAITS sequences of H. elachista amplified and the one reported by Tanha Maafi (GenBank accession number: AF498391) were analyzed. The restriction enzyme cutting sites of AluⅠ, AvaⅠ, MvaⅠ and RsaⅠ in these 11 sequences were identical, however there were 2 different patterns after Bsh1236Ⅰ and BsuRⅠ digestion, respectively, and 3 different patterns after CfoⅠ digestion. The results show intraspecies heterogeneity in rDNAITS region exists in H. elachista.

Short Communications

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Improving Resistance to Rice Stripe Disease of Restorer Line Ninghui 8 by Molecular MarkerAssistant Selection YAO Shu, CHEN Tao, ZHANG Yadong, ZHU Zhen, ZHAO Qingyong, ZHOU Lihui, ZHAO Ling, LI Yusheng, WANG Cailin* 2014, 28(1): 85-91.  DOI: 10.3969/j.issn.1001-7216.2014.01.012 Abstract ( )   PDF (1203KB) ( )   A molecular marker assisted selection (MAS) strategy was used to improve the resistance to rice stripe disease of Ninghui 8, the restorer line of japonica hybrid 86 you 8, by advanced backcross with Ninghui 8 as the recurrent parent and Kanto 194 as the donor of the rice stripe disease resistant gene. Markers tightly linked with Stvbi and Rf1a genes were used for selecting the two genes of the ability to recovery the sterility and to resistant the stripe disease, respectively. After identification of the rice stripe disease resistance and investigation of some agronomic traits, 10 resistance improved lines with similar characteristics as Ninghui 8 were developed in BC3F3 generation, and 4 lines with excellent characteristics were selected to cross with malesterile lines A25, A19 and A70, respectively. The results indicated that comprehensive characters of hybrid combinations from improved line2 were significantly better than those from Ninghui 8.

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A Preliminary Study on the Transfer Mode and Biological Significance of Endosymbiont Arsenophonus in Nilaparvata lugens CHEN Yu, CHEN Yang, WANG Weixia, LAI Fengxiang, FU Qiang* 2014, 28(1): 92-96.  DOI: 10.3969/j.issn.1001-7216.2014.01.013 Abstract ( )   PDF (664KB) ( )   According to direct and reciprocal cross test, Arsenophonus offspring infection was determined by female parents  rather than male parents,which indicated Arsenophonus was maternally inherited in the brown planthopper (BPH), Nilaparvata lugens. The newly emerged Arsenophonusinfected (positive) and uninfected (negative)  BPH were paired respectively, the number and sex of offsprings were recorded. The results indicated Arsenophonus infection did not significantly impact reproduction and sex ratio of BPH. It suggested that Arsenophonus had no malekilling function to BPH. The results showed that the infection rate of negative population to M. anisopliae ARSEF1764 (55.2 %) was significantly higher than that of positive population (32.5 %), which indicated Arsenophonus could improve the resistance of BPH to M. anisopliae.

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Mesocotyl Elongation of Weedy Rice and Its Relationship with Grain Amylase Activities and Soluble Sugar Contents MA Dianrong*, KONG Dexiu， LIU Xiaoliang, GAO Qi， DING Guohua, ZHAO Minghui， TANG Liang， XU Zhengjin, CHEN Wenfu* 2014, 28(1): 97-102.  DOI: 10.3969/j.issn.1001-7216.2014.01.014 Abstract ( )   PDF (896KB) ( )   The dynamic process of mesocotyl elongation of weedy rice was observed in a germination test in a constant temperature incubator in darkness. The changes in amylase activities in embryos and soluble sugar contents in the process of mesocotyl elongation and their relationship were analyzed. The results showed that during the first  three days after germination in darkness, the mesocotyl elongation rate was  very slow and accelerated four and five days after germination. The mesocotyl elongation gradually stopped seven days after germination.    The mesocotyl of the weedy rice was significantly longer than that of Liaojing 294. In the germination process of weedy rice,   soluble sugar contents followed an increasing trend, together with αamylase activity and βamylase activity. Mesocotyl elongation length    was significantly correlated with the αamylase activity, βamylase activity and soluble sugar contents. The enhanced  amylase activities in the beginning of weedy rice germination promoted starch degradation,  supplying material and energy for mesocotyl elengation.

Reviews and Special Topics

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Research Advances in the Physiological and Biochemical Mechanism in Watersaving Irrigation  Techniques for High Yield and High Efficiency of Transplanted Rice CHEN Tingting， YANG Jianchang* 2014, 28(1): 103-110.  DOI: 10.3969/j.issn.1001-7216.2014.01.015 Abstract ( )   PDF (601KB) ( )   The water crisis is threatening rice sustainability and food security in the world. Agricultural scientists have developed a variety of watersaving irrigation techniques and production systems in order to deal with water shortages meanwhile to increase food production. This paper reviewed dominant watersaving irrigation techniques applied in transplanted rice production, summarized their physiological and biochemical mechanism for  rice growth, hormones, and activities of key enzymes involved in sucrosetostarch conversion. The problems existed in watersaving irrigation techniques for highyielding and highefficiency of rice and research prospects were put forward and discussed.