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10 March 2012, Volume 26 Issue 2 Previous Issue    Next Issue
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Research Papers

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Molecular  Evolution and Expression Analysis of Subfamily ABCB Transporter Genes in Rice XU Xing, QIU Jie, XU Yang, XU Chenwu* 2012, 26(2): 127-136.  DOI: 10.3969/j.issn.10017216.2012.02.001 Abstract ( )   PDF (1843KB) ( )   With the accomplishment of genome sequencing projects, over 130 ABCs were identified separately from the model plants of monocots and dicots, rice and Arabidopsis, but the functions of most of the members remain elusive.   Therefore, 27 and 29 subfamily B of ABC genes (ABCB) in rice and Arabidopsis were systematically characterized, respectively. The exon number,  length  and molecular weight  of proteins  encoded by these genes varied greatly  between the two plants, albeit the isoelectric point was less diverse.  Proteins of this subfamily  were divided into 4 subgroups accordingpar to   phylogenetic analysis, suggesting that divergence probably occurred among them; 6 and 9 pairs of paralogous genes were identified from rice and Arabidopsis, respectively, indicating that speciesspecific expansion contributed to the evolution of this subfamily in rice and Arabidopsis after the split of monocots and dicots. Segmental and tandem duplication contributed to the amplification of ABC family in rice. Multiple sequence alignment revealed that the Walker A, Walker B, and ABC signature motifs of nucleotidebinding domain (NBD) are highly conserved, but less the Q and H loops; no significant conservatism could be pointed out as to TMD domain within a single ABC protein and  among different proteins. Expression of rice ABCB genes is highly tissuespecific, and divergence has occurred among the expression profiles of different genes. Expression analysis of rice ABCB genes under abiotic stress suggested that most of the genes are responsive to at least 1 type of stress factors.Ka/Ks calculation indicated that purifying selection is essential to the functional maintenance of genes after duplication.

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Molecular Cloning, Sequencing, and Expression of a Glucosamine6phosphate Synthetase Gene from Rice Pathogen Rhizoctonia solani  LUO Chuping1,3, LIU Yongfeng1, CHEN Zhiyi1,3，*, WANG Xiaoyu1, FANG Xianwen2, CHEN Zhongming2, LIU Youzhou1, NIE Yafeng1 , ZHANG Rongsheng1 2012, 26(2): 137-143.  DOI: 10.3969/j.issn.10017216.2012.02.002 Abstract ( )   PDF (2692KB) ( )   To  develop novel antimicrobial agents  to Rhizoctonia solani,   the genomic gene and complete cDNA encoding glucosamine6phosphate synthetase  were cloned and sequenced from the rice pathogen Rhizoctonia solani by   3′RACE and 5′RACE .  Homologous to other reported GlmS in  sequence,  the GlmS  contains eight introns, and encodes a predicted protein of 697 amino acids. Domain structure analysis revealed that R.solani GlmS contained a glutamine transferase motif and two sugar isomerase motifs. Recombinant native R.solani GlmS enzyme  was overexpressed using  Escherichia coli and purified. The results of Gel filtration chromatography and SDSPAGE revealed that it had an estimated molecular mass of 306 kD  and consisted of four equalsized subunits of 77 kD. The optimal reaction conditions for the recombinant GlmS were pH 6.4 at 37℃, the halflife  period  for the recombinant GlmS was 1 h at 42℃ and the enzyme was stable at pH 5.5-7.5. R.solani GlmS activity was inhibited by the endproduct of the hexosamine pathway, UDPGlcNAc.

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Unconditional and Conditional QTL Mapping for Yield and Yield Related Traits in japonica  Rice in Multienvironments LIU Jian, NIU Fuan, JIANG Jianhua, SUN Cheng, CHEN Lan, GUO Yuan, FU Shuhuan, HONG Delin* 2012, 26(2): 144-154.  DOI: 10.3969/j.issn.10017216.2012.02.003 Abstract ( )   PDF (468KB) ( )   To dissect the genetic basis of yield and its related traits, the QTLs controlling whole growth period (WGP), plant height (PH), number of panicles per plant (PN), number of grains per panicle (GN), hundredkernel  weight (HKW), grain yield (GY) and biomass yield (BY)  were detected by unconditional and conditional approaches  with the recombinant inbred lines derived from a cross between two  japonica varieties, Xiushui 79 and C Bao in three environments. Fourtythree  maineffect QTLs and 29 pairs of epistatic QTLs were detected.  By the unconditional method, 37 maineffect QTLs and 26 pairs of epistatic QTLs were detected. Three  maineffect QTLs, qGY1.2, qGY7.1 and  qGY9, were found for GY while no epistatic QTL was found for GY.  By the conditional method,  9 maineffect QTLs and 3 pairs of epistatic QTLs for GY including the three maineffect QTLs detected by unconditional methods were detected.  qGY9, in the interval RM6570-RM5652   on the long arm of chromosome 9, could be detected by unconditional method and conditional method when  WGP, PH, PN, GN and HKW were at the same levels, but the additive effect and the variance explained were different. The allele  of qGY9 contributed by  C Bao could increase GY through increasing PH, HKW and PN. The alleles at  the interval RM7097-RM448  on the long arm of chromosome 3 and the interval RM162-RM5753  on the long arm of chromosome 6 detected by the conditional method  which could increase GY had negative effects on PH and WGP.

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Genetic Diversity of Upland Rice Varieties in Yunnan Province Revealed by SSR Markers XU Jianxin, WANG Yunyue* , YAO Chun, LIU Yunxia, TANG Miao, LU Mingxing 2012, 26(2): 155-164.  DOI: 10.3969/j.issn.10017216.2012.02.004 Abstract ( )   PDF (1054KB) ( )   Genetic diversity of 131 Yunnan upland rice varieties was analyzed by using 24 SSR markers. The average number of alleles per locus was 8.125 with a range from 5(RM55) to 13(RM218, RM241).Mean observed heterozygosity and mean expected heterozygosity were 0.0014 and 0.6545, respectively. Average ShannonWeaver index (I) was 1.381. The Nei′s genetic diversity index (H) ranged from 0.2073(RM235) to 0.8689(RM218) with an average value of 0.6543. The southwest, south of Yunnan were the distribution center of genetic diversity of upland rice varieties in Yunnan, because the highest genetic variation was found in these areas. The analysis of molecular variance(AMOVA) indicated that 82% of the variation was from differences among varieties within regions, and only 3% was due to differences among regions and 15% within varieties.  The upland rice varieties  planted by TibetoBurman and the MonKhmer family had the most abundant genetic diversity. Cluster analysis showed those varieties could be divided into indica and japonica at the Nei′s genetic similarity of 0.22, but not by geographical distribution. The results of principal coordinates analysis were basically consistent with the UPGMA cluster, four partial indica varieties from group Ⅳ were reclassified into japonica group, the error of the UPGMA cluster was corrected.

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Comparison of Cheng’s Index and SSR Markersbased Classification of Asian Cultivated Rice WANG Caihong, XU Qun, YU Ping, YUAN Xiaoping, YU Hanyong, WANG Yiping, TANG Shengxiang, WEI Xinghua* 2012, 26(2): 165-172.  DOI: 10.3969/j.issn.10017216.2012.02.005 Abstract ( )   PDF (1772KB) ( )   A total of one hundred cultivated rice accessions were grouped based on Cheng’s index and SSR polymorphism. The results showed that the subpopulation features of allozyme groupⅠ (indica) and allozyme group ⅥA (temperate japonica) were obvious both classified by Cheng’s index and SSR  marker, with goodness of fit ranging from 73.3% to 100%. Mantel test revealed that the Euclidean distance of Cheng’s index was significantly correlated with Nei’s genetic distance of 109 SSR loci (r=0.466, P<0.01). According to both modelbased structure and UPGMA cluster analysis, the classification results at subspecies level based on Cheng’s index coincided with that on SSR marker. Within subspecies, the subpopulations classified by Cheng’s phenotypic characters showed lower goodness of fit than SSR marker. In addition, allozyme group Ⅱ (aus, boro) and allozyme group Ⅵ (temperate japonica, tropical japonica) had more mixture types based on SSR locus analysis.

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Characterization of Male Gametophytic Sterile Mutant Collections in Rice by TDNA Insertion CHEN Rui, YU Fake, LIU Huaqing, YANG Shaohua, WANG Feng* 2012, 26(2): 173-181.  DOI: 10.3969/j.issn.10017216.2012.02.006 Abstract ( )   PDF (1227KB) ( )   The abnormal genetic segregation   of more than 6,000 TDNA insertional transgenic rice lines(selectable marker gene hygromycin B phosphotransferase,hpt) was analyzed.  216 of them   showed 1∶1 segregation,  and 57 mutant lines were initially identified as male gametophytic sterile candidate mutants through test cross. Further multiple genetic analysis and pollen cytological observation indicated the blackdyed  pollen rates of one of the 38 candidate mutations were about 50%, TDNA abnormal separation of selfing progeny   due to the semisterility of  pollen of transgenic plants, TDNA  could be transferred   only  by  the female gametophyte. In addition, expression levels of cry1Ac (Bt) genes  tested by Enzyme Linked Immunosorbent Assay (ELISA) demonstrated  their pollen sterility and foreign gene expression had no direct relationship,  indiating that the abortion  of the  38 male gametophytic sterile mutants  was mainly attributed  to endogenous gene  variation  caused by TDNA insertion.  Flanking sequences of  22 TDNA insertional male gametophytic sterile mutants were obtained by TAILPCR. According to BLAST search, 15 different insertion sites were located, of which 12 were located in the gene or gene regulatory region.

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Analysis of Main Agronomic Traits Affecting Yield Level in Inbred indica  Rice Cultivars in South China LIU Chuanguang1, ZHOU Hanqin1, FENG Daoji1, ZHOU Xinqiao1, CHEN Dagang1, LI Lijun1, LI Juchang1, ZHANG Guiquan2,*, CHEN Youding1,* 2012, 26(2): 182-188.  DOI: 10.3969/j.issn.10017216.2012.02.007 Abstract ( )   PDF (407KB) ( )   Principal component analysis was carried out on 20 agronomic traits of 68 inbred  indica  rice cultivars, which were widely planted in South China in recent 50 years. The results indicated 85.1% of the total variations were contributed by the top  six factors among which the  factor of grain number per panicle made  the greatest contribution. The regression analysis result   showed that the standardized regression coefficient of biomass factor to yield was the greatest. It indicated that the biomass  was the most important factor to high yield. Based on the scores of the top  six factors, 68 cultivars could be classified into five groups. A comparison of the mean factor scores and the agronomic traits among the five  groups indicated that biomass   was a key factor which determined yield level. Spikelet number  and grain weight  followed  an opposite trend  among the cultivar groups, and if the score of   one factor is too low, the yield level   will be reduced significantly. Only when the two factors  maintained balance  at a  high biomass yield, the sink size and yield could be increased to a high level. It should be an important approach to increase the grain  yield potential in South China to maintain the balance between the grain number and grain weight at a higher level through increasing 1000grain weight based on large panicle and high biomass.

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Relationship Between Culm Lodging Resistance and  Population Quality of Hybrids    under  TrianglePlanted System of Rice Intensification  at  Different Nitrogen Application Rates and Planting Densities SUN Yongjian1,2, CHEN Yu1,2, SUN Yuanyuan1,3, XU Hui1,2, XU Yuanming4, LIU Shujin1,2, MA Jun1,2,* 2012, 26(2): 189-196.  DOI: 10.3969/j.issn.10017216.2012.02.008 Abstract ( )   PDF (491KB) ( )   The effects of nitrogen (N) application rate and planting density on population quality and culm lodging resistance of rice were investigated with hybrid rice combination Ⅱyou 498 as material under triangleplanted system of rice intensification (TSRI), and correlation of population quality with culm lodging resistance and  grain yield was analyzed. There was an obvious regulatory effect of N application rate and planting density on grain yield, population quality, and lodging resistance of rice culm under TSRI. Compared with other treatments, 150 kg/hm2 N application rate coupled with the suitable planting density (40 cm × 40 cm) improved leaf area index (LAI) and light transmission rate in rice population, coordinated bending moment and breaking resistance of basal internodes, alleviated contradiction of panicle and grain, and increased grain yield. At the nitrogen application rate of 225 kg/hm2, planting density should be reduced  to alleviate deterioration of population quality index and decreased lodging index. The suitable planting density was 50 cm × 50 cm. Correlation analysis indicated population quality was significantly  correlated with internode lodging resistance and yield. Middle part light transmission rate in rice population at full heading and 30 days after full heading, and amount of sap flow of rice root at 30 days after full heading   might be indicators for grain yield and culm lodging resistance.

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Nitrogen Absorption and Utilization Characteristics of  japonica  Rice Cultivars with Different Productivities at Their Optimum Nitrogen Levels  LI Min1,2 , ZHANG Hongcheng1,*, MA Qun1 , YANG Xiong1, LI Guoye1, WEI Haiyan1, DAI Qigen1, HUO Zhongyang1, XU Ke1 2012, 26(2): 197-204.  DOI: 10.3969/j.issn.10017216.2012.02.009 Abstract ( )   PDF (457KB) ( )   Based on the concept of the highest population productivity, the yield components and the characteristics of nitrogen absorption and utilization of three types of rice cultivars with low, medium  and high level of the  highest population productivities were investigated at their optimum nitrogen levels. With the increase of the highest population productivity, the total spikelet number increased remarkbly, while the seed setting rate and 1000grain weight showed no significant differences.  The nitrogen accumulation at Nn, heading and maturing stages increased correspondingly as the productivities increased, whereas no significant difference was found at elongation. In order to analyze the nitrogen absorption progress of rice genotypes with different productivities, the whole growth duration was divided into four phases, i.e., from transplanting to critical stage of productive tillering, from critical stage of productive tillering to elongation, from elongation to heading, and from heading to maturing. Results indicated that, the nitrogen accumulation during each period increased typically as the productivity increased during all growth phases except  the phase from critical stage of productive tillering to elongation.Compared with low productivity genotype, the nitrogen translocation amount and nitrogen translocation rate of mediumproductivity genotype increased evidently. However, there   was negligible difference between medium  and high productivity types. Based on the results above, it was concluded that   rice cultivars with the highest population productivity were featured by   rapid nitrogen absorption before Nn,  slow nitrogen absorption  from Nn to elongation, steady nitrogen absorption from elongation to heading, and massive nitrogen absorption from heading to maturing; and a large but not excessive amount of transferred nitrogen from stems and leaves after heading.

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Simulation of Leaf Inclination Angle Distribution for Rice  with Different Plant Types ZHANG Xiaocui1, LU Chuangen2, *, HU Ning3, YAO Kemin3, ZHANG Qijun2, DAI Qigen1，* 2012, 26(2): 205-210.  DOI: 10.3969/j.issn.10017216.2012.02.010 Abstract ( )   PDF (1220KB) ( )   A   model for simulating  leaf inclination angle distribution   was established by the plant type factors of three plant types，and validated by the present experiment. The coefficient of determination (R2) and the root mean square error （RMSE）between the simulated and measured values are 0.9472 and 3.93%, respectively.  The simulation results of the model  showed that  there was different distribution of leaf inclination angle in the  three plant types. The leaf inclination angle of compact plant type, Liangyoupeijiu  (erect leaves)  is larger than a loose plant type, Shanyou 63 (droopy leaves) and intermediate type, Liangyou Y06.  Shanyou 63 showed the lowest inclination angle of leaf which is consistent with  the observation. For a   variety, there was also different leaf inclination angle distribution at  the seven growth stages. Canopy leaf inclination angle became  larger and larger from transplanting to booting stage. After booting, with the advance of growing, leaf inclination angle of Shanyou 63 and Liangyou Y06 was getting larger, while Liangyoupeijiu showed little change. Canopy leaf inclination angle distribution at six heights showed different for a material  at a   growth stage. With the increase of canopy height, layered leaf area index decreased in the three plant types, and the leaf inclination angle of Liangyoupeijiu showed little change. However, with the increase of canopy height, leaf inclination angle was getting larger for Shanyou 63, and much smaller for Liangyou Y06. The present model proved that simulation results of the model come very close to the actual values.

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Effects of Application Volume and Approaches of Pesticide   on Controlling Major Pests  and Diseases   on  Different  Plant Type Rice at Late Growth Stage HUANG Shiwen1,2, LIU Lianmeng1, WANG Ling1, LIU Enyong1,2 , FAN Zenglan1,2, XIAO Danfeng1 , HOU Enqing1,2 2012, 26(2): 211-217.  DOI: 10.3969/j.issn.10017216.2012.02.011 Abstract ( )   PDF (419KB) ( )   The control efficiency as affected by pesticide volumes (PV) , spraying approaches (fine spray, coarse spray) to the major pests and diseases  on rice plants at late growing stage were evaluated. For the rice neck blast, rice spikelet rot disease and leaf folder occurred at upper parts of rice plants, the best control efficiencies were obtained by two times of fine sprays(TFS), and the worst by two times of coarse sprays(TCS)  at the same pesticide application level and PV for a given rice variety. The control efficiencies by  the first fine spray and then coarse spray (FFSCS)  or the  first coarse spray and then fine spray(FCSFS) showed no significant difference. The control efficiency to japonica Xiushui 09 was better than that of  the indica/japonica hybrid combination Yongyou 12. For a rice variety at the same pesticide application level, the best control efficiency was obtained  at  PVs of 675 or 750 L/hm2, followed by 900, 1200, 450 L/hm2 and 225 L/hm2. For a variety at a given PVs, the best control efficiencies to sheath blight and planthoppers occurred on the middle and lower parts of rice plants, were gained by TCS, followed by FCSFS, FFSCS, and TFS. Control efficiency for  Xiushui 09 was better than that for Yongyou 12 at a given PV and by the same approach. For a variety by the same spraying means, the best control efficiency was obtained at the PV of 900 L/hm2, followed by 1200 and 750 L/hm2. The less water and the worse control efficiency   when the   PV was less than 900 L/hm2. The control efficiencies  to sheath blight and planthoppers were less than 50%   at the PV of 225 L/hm2. and  by TFS, especially for Yongyou 12. At the same pesticide application level, the control efficiency didn’t increase with the rising PV.

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Virulence of Part Populations of Aphelenchoides besseyi on Rice in China PEI Yanyan1,2,#, CHENG Xi1,#, XU Chunling1, YANG Zaifu3, XIE Hui1,* 2012, 26(2): 218-226.  DOI: 10.3969/j.issn.10017216.2012.02.012 Abstract ( )   PDF (721KB) ( )   In order to reveal  the pathogenic difference of Aphelenchoides besseyi populations from different geographic regions and  hosts in China, a virulence   investigation  of eight  populations of A. besseyi from six provinces on rice  were carried out on potted rice in greenhouse. Among the eight  populations of A.besseyi, one were extracted from the strawberry (Fragaria ananasa) and seven  from rice. The results showed that all the eight  populations of A. besseyi infected 3 varieties of rice (Liaoyan 16, Wuyujing 3 and Boyou 998), but their virulence varied with rice variety and nematode population. infection with nematodes  caused various symptoms on different rice varieties with typical symptom of “white tip” on Liaoyan 16,  but  without obvious symptoms on the other two. All the varieties   inoculated with nematodes could tassel, but their  plant height, panicle number  per plant,  panicle length and 1000grain weight were affected to various degree. The results also showed that the virulence of A. besseyi  was related to the origin of host. The population of A. besseyi from the  strawberry had weaker virulence than those from rice. In addition, among all the eight  nematode populations,  infection by HN2  greatly inhibited the growth of   Liaoyan 16   with least  nematode.  It indicated that  this population had stronger virulence than the others.  It also showed that there was no positive correlation between the propagation number and virulence of A. besseyi. All the results indicated that there may be different physiological races or pathotypes of A.besseyi in China.

Reviews and Special Topics

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Genetics and Breeding Improvement for Panicle Type in Rice LIU Jian1,2 , TAO Hongjian1 , SHI Si1,3 , YE Weijun1,3 , QIAN Qian1 , GUO Longbiao1,* 2012, 26(2): 227-234.  DOI: 10.3969/j.issn.10017216.2012.02.013 Abstract ( )   PDF (624KB) ( )    Panicle type is one of the key agronomic traits closely related to plant types and yield, and the innovation of ideal plant architecture with largepanicle has been an important part of rice high yield breeding in the future. Six types and 19 subtypes of classification for panicle  were reviewed, such as the degree of erect panicle type, grain number per panicle, weight per panicle, seed density and so on. So far, at least 200 kinds of panicle type mutants were obtained, 1386 QTLs for rice panicle types (involving panicle length, panicle number, grain width, grain number per panicle, and seed setting rate) were identified. More than 16 panicle typerelated QTLs including  Dep1, Ghd7, Gn1a, Ipa1  and GW2 were cloned. Four kinds of breeding improvement ways for erect panicle type, largepanicletype, heavy panicle type and latestage vigor type rice were emphatically reviewed, and molecular breeding strategies of doublegene polymerization were summarized such as  Gn1/sd1 or Gn1/DEP1 using new cloned panicletype genes. The development of panicletype research in rice will provide more methods and thoughts for ideal plant architecture with largepanicle  and super rice with erectlargepanicletype.

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Quantitative Trait Loci for Heading Date and Their Relationship with the Genetic Control of Yield Traits in Rice (Oryza sativa) GUO Liang, ZHANG Zhenhua, ZHUANG Jieyun* 2012, 26(2): 235-245.  DOI: 10.3969/j.issn.10017216.2012.02.014 Abstract ( )   PDF (518KB) ( )   Grain yield and heading date are key factors determining the commercial potential of a rice variety. Mapping of quantitative trait loci (QTLs) in rice has been advanced from primary mapping to gene cloning, among which heading date and yield traits have always attracted the greatest attention. In this review, genomic distribution of QTLs for heading date detected in populations derived from intraspecific crosses of Asian cultivated rice (Oryza sativa) was summarized, and their relationship with the genetic control of yield traits was analyzed. The information could be useful in the identification of QTLs for heading date and yield traits that are promising for the improvement of rice varieties.

Experimental Techniques

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Simultaneous Quantitative Determination of Ustiloxin A and Ustiloxin D in Rice  Grains by High Performance Liquid Chromatographytandem Mass Spectrometry JI Fang, CAO Huan, XU Jianhong, YIN Xianchao, SHI Jianrong* 2012, 26(2): 246-250.  DOI: 10.3969/j.issn.10017216.2012.02.015 Abstract ( )   PDF (527KB) ( )   A method based on high performance liquid chromatography coupled with tandem mass spectrometry(HPLCMS/MS) was developed for simultaneous determination of  ustiloxin A and ustiloxin D. This method is simple，sensitive and accurate, and can be used for simultaneous quantitative determination of ustiloxin A and ustiloxin D in rice grains.

Short Communications

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Physiological Effects of Rapid Cold Hardening on   Diapause Larvae of Rice Stem Borers, Chilo suppressalis Walker (Lepidoptera: Pyralidae) QIANG Chengkui1,2,# , YU Lingya3,# , DU Yuzhou1,* , QIN Yuehua2 , ZHAO Hu2 , HU Changxiao2 2012, 26(2): 251-254.  DOI: 10.3969/j.issn.10017216.2012.02.016 Abstract ( )   PDF (625KB) ( )    To understand physiological effects of rapid cold hardening (RCH) on the diapause larvae of the rice stem borer, Chilo suppressalis Walker, at physiological and biochemical levels, the contents of water, lipid, total sugar, lowmolecular weight carbohydrates and the actitives of SOD, POD, CAT in the diapause larvae were measured. The results showed that the content of water in RCHtreated larvae was significantly lower than that  under the check at 0.05 probability level, while the activity of POD was in adverse. The contents of lipid, total sugars, trehalose, glucose, glycerol and the activities of SOD, CAT showed no significant difference. The content of water of  larvae  under nonrapid cold hardening(NRCH) was significantly lower than that  under the check, while the acitivity of POD was in adverse and the rest showed no significant difference. The activities of POD of RCH larvae were just significantly higher than those of NRCHtreated larvae (P<0.05). Therefore,  RCH could enhance physiological effects of water and POD on the diapause larvae.