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10 May 2012, Volume 26 Issue 3 Previous Issue    Next Issue
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Research Papers

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Expression Patterns of OsPIL11, a Phytochromeinteracting Factor in Rice, and Preliminary Analysis of Its Roles in Light Signal Transduction LIANG Weihong1,*, LI Li1,2, PENG Weifeng1,2, LIU Jing2, YANG Hui2, XIE Xianzhi2, 3,* 2012, 26(3): 255-260.  DOI: 10.3969/j.issn.10017216.2012.03.001 Abstract ( )   PDF (741KB) ( )   The expression patterns of OsPIL11,  one of  six putative phytochromeinteracting factors(PIFs), were analyzed, revealing that expression of OsPIL11was organspecific and  regulated by leaf development, ABA, JA and SA.  To further explore the role of OsPIL11in plant light signal transduction, plant expression vector of OsPIL11was constructed and introduced into tobacco(Nicotiana tabacum).  In continuous red light(R), OsPIL11overexpressed transgenic lines exhibited shorter hypocotyls and larger cotyledons and leaves compared to wildtype seedlings. While  in continuous farred light(FR),  either transgenic or wildtype seedlings showed similar phenotypes. These results indicated  that OsPIL11was involved in Rinduced deetiolation, but not in FRinduced deetiolation in transgenic tobacco.

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Expression Analysis of Genes Encoding Deoxycytidine/Cytidine Deaminases in Rice WANG Xuejun1 , KANG Houxiang2 , LIU Zhongsong1, * ， WANG Guoliang1,2,* 2012, 26(3): 261-266.  DOI: 10.3969/j.issn.10017216.2012.03.002 Abstract ( )   PDF (3107KB) ( )   The phylogenetic relationship among the seven deoxycytidine/cytidine deaminase genes and the expression of these genes in different tissues and under different stresses were analyzed. Realtime PCR analysis showed that the seven genes had different expression characteristics in roots, stems and leaves with relative high expression levels in leaves and low expression levels in rice stems. Furthermore, the expression of most  genes was stressinduced including chillness, drought, salination and disease infection, but only the expression of Os07g0245100 was induced by all four stresses. Our results demonstrated that the deoxycytidine/cytidine deaminase genes might play an important  role in abiotic and biotic responses.

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Proteomics Analysis of Nutrient Deficiency Effect on Rice Grain Filling SHAO Caihong, QIAN Yinfei, TANG Xiuying, LIU Guangrong, XIE Jinshui, PENG Chunrui, QIU Caifei 2012, 26(3): 267-274.  DOI: 10.3969/j.issn.10017216.2012.03.003 Abstract ( )   PDF (4067KB) ( )   In order to determine the effect of nutrient deficiency on rice grain filling and lay the scientific basis for highyielding cultivation, the protein expression profiles in grains of early hybrid rice Weiyou 916 were analyzed by proteomics  approach under nutrition deficiency and full nutrition application at late developmental stage. Twodimensional electrophoresis gel analysis showed that 37 protein spots changed in abundance, 27 proteins involved photosynthesis (4 proteins), grain development (13 proteins), stress response (9 proteins) and respiration (1 protein) were identified by ESIQ MS/MS. Under nutrient deficiency conditions, proteins associated with stress response upregulated in expression abundance at early and middle filling stage, photosynthesis decreased and respiration increased at later stage. The nitrogen metabolism was affected by nutrient deficiency，resulting in delayed synthesis of glutein and germlike proteins, and low accumulation of protein and fat, which may result in insufficient grain filling and low yield.

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Expression of Transcription Factors of Rice Flag Leaf under Low Nitrogen Stress ZHAO Minghui, MA Dianrong, WANG Jiayu, XU Hai, TANG Liang, CHEN Wenfu 2012, 26(3): 275-282.  DOI: 10.3969/j.issn.10017216.2012.03.004 Abstract ( )   PDF (672KB) ( )   The expression changes of transcription factor genes in two rice cultivars with different chlorophyll content were analyzed under low nitrogen stress by the Agilent rice genome array. The results showed that the expression levels of 53 transcription factor genes (35 downregulated genes and 18 upregulated at the transcription level) in flag leaf of supergreen rice Shennong 196(SN196) and 27 (21 downregulated and 6 upregulated at the transcription level) in flag leaves of Toyonishiki were affected by low nitrogen stress.48 genes from SN196 and 22 from Toyonishiki were cultivarspecial in response to low nitrogen stress.There were five transcription factor genes in response to low nitrogen stress in SN196 and Toyonishiki, with 1 upregulated and 4 downregulated at the transcription level, respectively. Expression of transcription factor genes were affected by low nitrogen stress in flag leaf, and there were  genes of cultivar specialresponse as well as overlap between SN196 and Toyonishiki, respectively.Distribution of low nitrogen stress regulating genes on the rice chromosomes of the two cultivars was different.

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QTL Analysis for Seven Quality Traits of  japonica Rice  Based on Three Genetic Statistical Models LIU Qiangming1， JIANG Jianhua1,2， NIU Fuan1， HE Yingjun1， HONG Delin1,* 2012, 26(3): 283-290.  DOI: 10.3969/j.issn.10017216.2012.03.005 Abstract ( )   PDF (1480KB) ( )   QTL mapping for seven quality traits was conducted by using 254 recombinant inbred lines derived from a  japonicajaponica  rice (Oryza sativa L.) cross of Xiushui 79/C Bao. The seven  traits were grain length (GL), grain length to width ratio (LWR), percentage of grains with chalkiness (PGWC), degree of endosperm chalkiness (DEC), gelatinization temperature (GT), amylose content (AC) and gel consistency (GC) of headrice. Three mapping methods employed were composite interval mapping in QTLMapper 2.0 software based on mixed linear model (MCIM), the inclusive composite interval mapping in QTL IciMapping 3.0 software based on stepwise regression linear model (ICIM) and the multiple interval mapping with regression forward selection in Windows QTL Cartographer 2.5 based on multiple regression analysis (MIMR). Five QTLs with additive effect (AQTLs) were detected by all the three methods simultaneously, two by two methods simultaneously, and 23 by only one method. Five AQTLs were detected by MCIM, nine by ICIM and 28 by MIMR. The contribution rate of single AQTL ranged from 0.89% to 38.07%. All the QTLs with epistatic effect (EQTLs) detected by MIMR were not detected by the other two methods. Fourteen pairs of EQTLs  were detected by both MCIM and ICIM, and 142 pairs of EQTLs were detected by only one method. Twentyfive  pairs of EQTLs were detected by MCIM, 141 pairs by ICIM and four pairs by MIMR. The contribution rate of a single pair of EQTL was from 2.60% to 23.78%. In the XiuBao RIL population, epistatic effect played a major role in the variation of GL and DEC, and additive effect was the dominant in the variation of LWR, while epistatic effect and additive effect had equal importance in the variation of PGWC, AC, GT and GC. QTLs detected by two or more methods simultaneously were highly reliable, and could be applied to improvement of the quality in  japonica  hybrid rice.

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QTL Analysis for Leaf Number on Main Stem in RILs of Super Hybrid Rice Xieyou 9308 DAI Gaoxing1,2, YANG Zhanlie1,3, DENG Guofu2, ZHANG Yingxin1, WANG Huimin1, ZHAI Rongrong1, CAO Liyong1,*, CHENG Shihua1,* 2012, 26(3): 291-296.  DOI: 10.3969/j.issn.10017216.2012.03.006 Abstract ( )   PDF (1312KB) ( )   QTLs for leaf number were identified with a set of recombinant inbred lines (RILs) derived from the cross of Xieqingzao B/Zhonghui 9308   as materials   by the conditional composite interval mapping method. Five unconditional QTLs and two conditional QTLs were detected at different growth stages. The unconditional QTLs, qLN2.1, qLN2.2, qLN2.3 and qLN2.4, explained 11.68%-16.48% of phenotypic variation, tending to cluster on the long arm of chromosome 2. QTL analysis showed that the express period of conditional QTLs, qLN2.2 and qLN2.4, were unanimous to the dates of elongating and heading. Only one unconditional QTL for  final leaf number was detected, but there was no effect of conditional QTL at all the tested developmental stages, indicating QTLs for  leaf number were mainly expressed in spatial and temporal patterns.

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Genetic Analysis and Gene Mapping of a Light Brown Spotted Leaf Mutant in Rice FENG Baohua1, YANG Yang1,2, SHI Yongfeng1, LIN Lu3, CHEN Jie1, HUANG Qina1， WEI Yanlin1,2, Hei LEUNG4, WU Jianli1,* 2012, 26(3): 297-301.  DOI: 10.3969/j.issn.10017216.2012.03.007 Abstract ( )   PDF (696KB) ( )   A light brown spottedleaf mutant of rice was isolated from an EMSinduced IR64 mutant bank. The mutant, designated as lbsl1（light brown spottedleaf 1）, displayed light brown spot in the whole growth period from the first leaf to the flag leaf under natural summer field conditions. Agronomic traits including plant height, growth duration, seedsetting rate and 1000grain weight of the mutant were significantly affected. Genetic analysis showed that the mutation was controlled by a single recessive gene, tentatively termed lbsl1(t), which was mapped to the short arm of chromosome 6. With developed SSR markers, the gene was finally delimited to an interval of 130 kb between markers RM586 and RM588. The lbsl1(t) gene is likely a novel rice spottedleaf gene since no other similar genes have been identified near the chromosomal region. The genetic data and recombination populations provided will facilitate further fine mapping and cloning of the gene.

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Postanthesis Changes in Activities of Enzymes Related to Starch Synthesis and Contents of Hormones in Superior and Inferior Spikelets and Their Relation with Grain Filling of Super Rice FU Jing, XU Yunji, CHEN Lu, YUAN Limin, WANG Zhiqin, YANG Jianchang* 2012, 26(3): 302-310.  DOI: 10.3969/j.issn.10017216.2012.03.008 Abstract ( )   PDF (2010KB) ( )   The changes in activities of key enzymes involved in sucrosetostarch conversion and contents of hormones in superior and inferior spikelets were investigated and their relation with grain filling of super rice was analyzed with four super rice cultivars, Liangyoupeijiu and Ⅱyou 084 (indica  hybrids), Huaidao 9 and Wujing 15 (japonica), and two highyielding and elite check cultivars, Shanyou 63 (indica hybrid) and Yangfujing 8 (japonica)as material in paddy field. Activities of sucrose synthase (SuSase), adenosine diphosphoglucose pyrophosphorylase (AGPase), starch synthase (StSase), and starch branching enzyme (SBE) and contents of zeatin + zeatin riboside (Z+ZR), indole3acetic acid (IAA), abscisic acid (ABA) in superior and inferior spikelets were determined during the grain filling period and their relationships with grain filling rate were analyzed. Maximum grain filling rate, the time reaching a maximum grainfilling rate, mean grain filling rate and brown rice weight for superior spikelets slightly differed between super rice and elite check rice, but those for inferior spikelets were significantly different between super rice and check rice cultivars. Changes in enzyme activity and contents of hormones in grains followed single peak curves during the grain filling period. The peak and mean activity of SuSase, AGPase, StSase and SBE were lower in inferior spikelets than in superior ones,as well as the peak and mean contents of Z+ZR, IAA and ABA. The peak and mean contents of ABA were significantly greater in inferior spikelets than in superior ones and greater in the super rice than in the check rice. The grain filling rate was positively significantly correlated with the activities of SuSase, AGPase and StSase and contents of Z+ZR and IAA, but not significantly correlated with activity of SBE and ABA contents. The results suggested that the low activities of SuSase, AGPase and StSase and low contents of Z+ZR and IAA may be an important reason for the slow grain filling rate and low grain weight of inferior spikelets in super rice.

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Effect of Seedling Standing and Establishment on Photosynthetic Characteristics and Matter Production of Broadcasted Rice GUO Baowei1, ZHANG Hongcheng1,*, ZHANG Chunhua1, CHEN Houcun2, XU Ke1, ZHOU Xingtao1, ZHANG Jun1, CHEN Jingdu1, WEI Haiyan1, DAI Qigen1, HUO Zhongyang1, GAO Hui1, ZHU Congcong1, XING Lin1, HUANG Xingfu1 2012, 26(3): 311-319.  DOI: 10.3969/j.issn.10017216.2012.03.009 Abstract ( )   PDF (829KB) ( )   The photosynthetic characteristics and matter production of broadcasted rice seedlings were studied to lay a theoretic basis for highyielding and superhighyielding cultivation of broadcasted rice with Nanjing 44 as material under five treatments  including the upright seedlings with soil(USWS), leaning seedlings with soil(LESWS), lying seedlings with soil(LASWS), lying seedlings without soil(LASWTS), upright seedlings without soil(USWTS). Results were as follows: 1) Seedling standing speed showed the trend of LESWS> LASWS> LASWTS; 2) LAI of LASWTS kept decreasing during seedling standing period, while LAI of others increased. The proportions of yellow leaf in LASWTS, USWTS, LESWS, LASWS and USWS reached their peaks at 8 d, 6 d, 2 d, 2 d, 2 d after broadcasting, respectively, and fell thereafter. 3) The dry weight of the aboveground parts all increased except LASWTS during the seedling standing period, with the general increasing rate of USWS>LESWS>LASWS>LESWTS>USWTS. Moreover, the dry matter accumulation, leaf area duration and net assimilation rate under various treatments showed the same trend. 4) Tiller number, population LAI, effective LAI rate, efficient LAI rate, ratio of grain to leaf area, photosynthetic potential, net assimilation rate, dry matter accumulation and growth rate of broadcasted rice at different growth stages all exhibited the trend of USWS>LESWS, USWTS>LASWS>LASWTS, and the net photosynthetic rate at heading stage and 20 d after heading showed the same trend as well. Given these observations, it could be concluded that the process of standing and establishment of seedlings with soil was faster than that without soil, and that of upright or leaning seedlings was faster than that of lying seedlings, which could be altributed to their stronger population growth during the whole period. Therefore, it is needed to choose seedlings with soil and to increase the proportion of the upright seedlings in order to obtain better photosynthetic characteristics and higher matter production capability, thus making for preferable plant growth and higher yield formation.

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Effect of Aeration on Root Growth and Nitrogen Metabolism in Rice XU Chunmei, WANG Danying, CHEN Song, CHEN Liping, ZHANG Xiufu* 2012, 26(3): 320-324.  DOI: 10.3969/j.issn.10017216.2012.03.010 Abstract ( )   PDF (737KB) ( )   In order to clarify the effects  of aeration on   root nitrogen metabolism in rice seedling, root growth, the activities of glutamine synthetase (GS), glutamic acidpyruvic acid transaminase (GPT), glutamic acid oxaloacetate transaminase (GOT), the contents of nitrate (NO3N), free amino acids and sugar content in root were investigated under continous aeration treatment in hydroponics with indica  hybrid rice combination Guodao 6 and japonica Xiushui 09 as material. The results showed that rice seedlings grown in oxygenation solutions had higher root dry matter, longer root length, stronger root activity and larger root absorption area, compared with the control. In addition, the contents of nitrate, soluble sugar, root vigor, the activities of GS, GOT and GPT of aerationtreated rice plants were higher than those of the control. The activities of enzymes involved in root nitrogen metabolism of “Xiushui 09” were enhanced by oxygenation. However, oxygenation had no significant influence on root nitrogen metabolism of Guodao 6, which suggested  that oxygenation effect on rice root nitrogen metabolism might be genotypespecific.

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Relationship Between Lodging Resistance and Either Agronomic Traits or Parents′ Lodging Resistance in Plateau japonica Rice DING Mingliang1,2,#, SU Zhenxi2,#, ZOU Qian2, ZHU Zhenhua2, YUAN Pingrong2, CHEN Yumin2, LIU Weihua2, LU Shugang1, DAI Luyuan2,* 2012, 26(3): 325-330.  DOI: 10.3969/j.issn.10017216.2012.03.011 Abstract ( )   PDF (392KB) ( )   Lodging resistance of  26 varieties and lines of plateau japonica rice was evaluated by investigating  20 traits(7 classes) including plant height, panicle  weight, panicle  length,    internode  length,    internode  wall thickness,   node diameter etc. The relationship between lodging resistance and pedigrees of the rice varieties  was analyzed. The results showed lodging resistance was not significantly correlated with    panicl  length,    panicle weight, and     internode diameter,  while significantly correlated with the rest 4 classes of   traits. Pedigree analysis showed  lodging resistance of varieties was closely correlated with that of  their parents.   Among there traits,   plant height,    internode lengths,  thickness of internode wall, and   diameter of node have significant correlation  with lodging resistance.   Lodgingresistant parents help improve lodgying resistance of  bred varieties.

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Difference in Nitrogen Absorption Ability and Its Reason in Conventional Japonica Rice Cultivars with Different Nitrogen Uptake Efficiencies YU Xiaofeng1, WANG Jiangang1,2, LI Jinqian1,3, WANG Yi1, YUAN Qiumei1, ZHONG Jun1, CHEN Chen1, TIAN Hao1, ZHANG Yan1, HUANG Jianye1, WANG Yulong1, DONG Guichun1,* 2012, 26(3): 331-340.  DOI: 10.3969/j.issn.10017216.2012.03.012 Abstract ( )   PDF (914KB) ( )   To investigate the main factors influencing nitrogen absorption ability and analyze its reason in conventional japonica rice cultivars with different nitrogen uptake efficiency, dry matter weight, nitrogen content, grain yield and its components were measured with 94 cultivars as materials in a hydroponic experiment in 2008 and 2009. Based on the amount of nitrogen absorption (ANA), these rice varieties were clustered into 6 types(in low to high order A, B, C, D, E and F) by the MinSSw (dynamic clustering methodminimum sum of squares within groups) method.Results were as follows: 1）Great differences in ANA were detected among all the tested cultivars with the maximum being 2.44 times as high as the minimum.The average grain yield of rice cultivars with high N uptake efficiency were significantly higher than those with low N uptake efficiency; 2）The rice cultivars with high N uptake efficiency had significantly higher ANA than those with low N uptake efficiency during pre and postheading stages. The ANA before heading had significantly higher effect on the total ANA than the ANA at grain filling stage; 3）The ANA of single panicle of rice cultivars with high N uptake efficiency was significantly higher than those of rice cultivars with low N uptake efficiency. However, there was no significant difference in panicle number per square meter among different rice cultivars. The ANA of single panicle exerted significantly greater effect on total ANA than the panicle number; 4）The rice cultivars with high N uptake efficiency had longer days from sowing to heading, growth duration, stronger N uptake intensity per panicle and per hill than those with low N uptake efficiency. The influence of N uptake intensity on ANA was significantly greater than that of  growth duration; 5）Dry matter accumulation of rice cultivars with high N uptake efficiency was significantly higher than that  of rice cultivars with low N uptake efficiency.However, compared with rice cultivars with low N uptake efficiency, the N content of rice cultivars with high N uptake efficiency had no advantage. Dry matter accumulation is one of the main factors influencing N absorptive capacity; 6）The ANA in  root, stem and leaf sheath, panicle of  rice cultivars with high N uptake efficiency were significantly higher than those of  rice cultivars with low N uptake efficiency.  The larger nitrogen transfer amount from stem, leaf and sheath to panicle after heading increased with rising ANA of stem, leaf and sheath before heading, which led to higher ANA of panicle at maturity stage and finally improved the ANA in the rice cultivars with high N uptake efficiency.

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Isolation, Identification and Biological Characters of Pathogens  of Rice Spikelet Rot Disease HUANG Shiwen1,2, WANG Ling1 , LIU Lianmeng1, LIU Enyong1,2, HOU Enqing1,2, XIAO Danfeng1,2,FAN Zenglan1,2 2012, 26(3): 341-350.  DOI: 10.3969/j.issn.10017216.2012.03.013 Abstract ( )   PDF (2533KB) ( )   In recently years, rice spikelet rot disease (RSRD) is a kind of fast rising main disease in rice panicle,  not only causing  rice yield loss but also reducing the quality of rice grains. Based on the morphological, biological and molecular characteristics,four fungal pathogens isolated from the infected rice grains were identified as Fusarium proliferatum, Bipolaris australiensis, Curvularia lunata and Alternaria tenuis,  respectively. The four pathogens could grow  at 4℃~40℃, pH 3~pH 12. The optimal temperature ranged from 25℃ to 30℃, and the best pH value for sporulation of the four pathogens differed. The four  isolates could grow on different  carbon and nitrogen sources  with    great difference  in  mycelial growth and sporulation. The experimental results indicated that RSRD is a kind of rice panicle disease caused by multipathogens, and the pathogens showed the characteristics of diversity, complexity and pathogenicity differentiation.

Short Communications

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Identification of QTL for Protein Content in Brown and Milled Rice in Two Enironments YANG Yachun， NI Dahu， SONG Fengshun， LI Li， FENG Guang， LI Zefu， YANG Jianbo* 2012, 26(3): 351-355.  DOI: 10.3969/j.issn.10017216.2012.03.014 Abstract ( )   PDF (1163KB) ( )   Based on single seed descend method a recombinant inbred lines  population consisting of 190 lines  was created by crossing two rice varieties with similar apparent amylose content, Nipponbare (japonica) and 9311 (indica) by QTLs for brown rice protein content(BRPC) and milled rice protein content (MRPC) with a genetic linkage map including 202 SSR, CAP and STS markers were identified. By composite interval mapping method in two environments sites (Sanya Hainan Province, China and Hefei Anhui Province, China), a total of nine QTLs were identified, indicating that rice protein content was controlled by multiple genes.  qBRPC1.3 was detected at the two sites with high stability, explaining 9.4% of total variation. The interval RM578-RM10596 on chromosome 1, controlled BRPC and MRPC, explaining 6.4% and 5.7% of total variation, respectively.

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Structure and Composition of Polysaccharide from Chlamydospore Wall in Ustiloginoidea virens WANG Na1, REN Zuohua1, DENG Linwei2, CHEN Juanfang3 , LIU Erming1，* 2012, 26(3): 356-360.  DOI: 10.3969/j.issn.10017216.2012.03.015 Abstract ( )   PDF (831KB) ( )   To reveal the relationship between endogenous dormancy mechanism of chlamydospores of U.virens and their walls, polysaccharide from cell walls of the dormant (black) and nondormant (yellow) chlamydospores was obtained by complex enzymehot water extractionSevag after the chlamydospores wall breaking through liquid nitrogen grinding plus ultrasonic crushing technique, and structure and composition of cell wall polysaccharide were analyzed by ultraviolet absorption spectrum (UV spectrum)，infrared absorption spectrum (IR spectrum), Congo red test, and gas chromatography (GC). The results showed that the polysaccharide from two kinds of the chlamydospores wall was acidic heteropolysaccharide and mainly consisted of the three monosaccharides, glucose, galactose and mannose, but the yellow chlamydospores wall still contained a small amount of xylose. Further,   polysaccharide in the black chlamydospores wall, was composed of glucose, galactose, mannose with a molar percentage ratio of 58.23∶25.32∶16.46，while the yellow chlamydospore wall was composed of glucose, galactose, mannose and xylose, with a molar percentage ratio of 35.48∶30.58∶24.46∶9.45. The composition and composition ratios of monosaccharides in polysaccharide from the dormant and nondormant chlamydospore walls obviously varied, which may be closely related to chlamydospore dormancy.

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Effects of Sublethal Dose of Imidacloprid and Pymetrozine on Relative Biological Fitness of Brown Planthopper, Nilaparvata lugens LIU Shuhua1 , YANG Baojun1 , LIU Shuang2 , DING Zhiping3, LIU Zewen3 , TANG Jian1,* 2012, 26(3): 361-364.  DOI: 10.3969/j.issn.10017216.2012.03.016 Abstract ( )   PDF (570KB) ( )   Longterm influences of sublethal dose of imidacloprid and pymetrozine on reproduction and biological fitness of the brown planthopper(BPH) were evaluated. Bioassay results showed that the LC50 values for imidacloprid and pymetrozine were 42.41 mg/L and 396.46 mg/L, respectively,  suggesting imidacloprid was approximately 9.35 times more toxic  than pymetrozine. The effects of the sublethal dose (LC30) of imidacloprid and pymetrozine on  the fitness of the brown planthopper  were evaluated by constructing and comparing the life  tables. Results revealed that   the biological  fitness of BPH exposed to imidacloprid and  pymetrozine had reduced to only 83.8% and 8.4% of the control, respectively. In imidacloprid treatment,  there was only an obvious decline in emergence rate of adult. However,  the emergence rate of adult, female adult ratio, female adult duration and eggs hatching rate  were conspicuously reduced under pymetrozine  treatment. In addition, the egg laying and fecundity fastigium of BPH  exposed  to sublethal pymetrozine were postponed compared to the control, which is probably  correlated with the delayed development of genitalia caused by pymetrozine’s feeding inhibition effects.

Reviews and Special Topics

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Mechanism of Zn Uptake, Translocation  in Rice Plant and  Znenrichment  in Rice Grain YU Yinjiang1, LIAO Haibing1, CHEN Wenrong1,*, TIAN Shengke2, YANG Xiaoe2 2012, 26(3): 365-372.  DOI: 10.3969/j.issn.10017216.2012.03.017 Abstract ( )   PDF (469KB) ( )   Zinc (Zn) is an essential but easy to be deficient micronutrient for human beings around the world. Zinc biofortification through staple food crops is suggested as an effective way to solve this problem. Unveiling the mechanism of Zn uptake, translocation and accumulation in edible parts is regarded as a critical step. Zinc uptake by rice roots  largely depends on: 1) excretions (such as mugineic acid)   activating  the Zn ion, and 2) the heavy metal transporter uptaking the Zn2+ into root symplasm, among which the ZIP gene families are reported to be very important. Zinc transport in xylem are mainly in the forms of ions, but also reported to be associated with organic acid, nicotinamide and other ligands. Retranslocation of Zn by phloem  takes a vital role in  the Zn  accumulation in rice grains. Preferential localization of Zn in aleurone and/or association of Zn with phytic acid significantly reduce the Zn bioavailability in rice. Unveiling the mechanism of Zn accumulated in grains and improving the Zn density in rice grains through modern biotechnology may convert the problem of Zn deficiency for human beings. This review summarized the latest progresses  in researches on physiological function of Zn in rice, Zn uptake, translocation, remobilization, Zn distribution and in vivo speciation in rice, as well as Zn biofortification in food crops.

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Advances in Genetic Analysis and Molecular Regulation Mechanism of Heading Date in Rice (Oryza sativa L.) HU Shikai, SU Yan, YE Weijun, GUO Longbiao* 2012, 26(3): 373-382.  DOI: 10.3969/j.issn.10017216.2012.03.018 Abstract ( )   PDF (1954KB) ( )   Heading date   is one of the most important agronomic traits closely related to rice yield in rice.The genetic pattern, growth and development characters of heading date in rice were reviewed. A total of 618 rice QTLs mapped and some important functional genes, such as Hd1, Hd3a, Ghd7, Ehd1 etc,  were involved in control of  the heading date. The regulation network of these headingdate genes has been preliminary established. The challenge of heading date mechanism research in rice and their prospects of applications in practice were dicussed.