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10 July 2016, Volume 30 Issue 4 Previous Issue    Next Issue
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Research Papers

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Overexpression of OmR40c1, a Ricin_B Lectin from Oryza meyeriana L. Enhances  Salt Tolerance in Transgenic Plants CHEN Xian12; DONG Yan23; ZHOU Jie2; WANG Xu ming2; YAN Cheng qi2*; CHEN Jian ping12* 2016, 30(4): 335-344.  DOI: 10.16819/j.1001-7216.2016.6006 Abstract ( )   HTML ( )   PDF (3498KB) ( )   Salt stress is a major environmental factor limiting rice growth and productivity in saline soil. Planting tolerant line is still the most effective way in response to salt stress. OsR40c1is an abscisic acid (ABA) and salt stressinduced gene. However, the function of OmR40c1is poorly studied. Here, we cloned a gene from Oryza meyeriana which shared the same CDS with OmR40c1but differed in 5′&3′ UTR. Subcellular location analysis showed that OmR40c1was located in cytoplasmic membrane and nuclear. OmR40c1 overexpressing transgenic rice was obtained by using the Agrobacteriummediated gene transfer system. OmR40c1might involve in seed germination. The germination rate of OmR40c1 transgenic rice was slightly affected by salt stress, while wild type decreased about 50% compared with their mocks. The seedlings of wild type hardly grown on the 1/2 MS medium with salt (174 mmol/L NaCl), the height of 10day OmR40c1  transgenic rice seedling decreased more than a half. Green leaves and root of OmR40c1 and wild type rice were both seriously affected by salt stress. The concentration of Na+ in OmR40c1 was about 1.38 times higher than that in wild type, together with a slight rise in the K+ concentration and the results suggest that OmR40c1 may act as a salt tolerance gene in enhancing rice salt tolerance especially at the adult stage.

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Identification and Gene Fine Mapping of a Brittle Culm 16 (bc16) Mutant in Rice SHU Yazhou, ZENG Dongdong, QIN Ran, JIN Xiaoli, ZHENG Xi, SHI Chunhai* 2016, 30(4): 345-355.  DOI: 10.16819/j.1001-7216.2016.5184 Abstract ( )   HTML ( )   PDF (4443KB) ( )   Brittle culm mutants are one of the important materials to study plant mechanical strength. A brittle culm mutant named as bc16 (brittle culm 16) was isolated from Nipponbare through EMS (Ethyl Methane Sulphonate) treatment. Compared with wild type,  bc16  featured fragile and easily broken stems,leaves,roots, lower plant height and filled grains per panicle, shorter panicle length and main root length. The components analysis of stem cell wall showed that the cellulose content in bc16 mutant was sharply decreased, while hemicellulose content was evidently increased and no significant difference had been found in the lignin content between bc16 mutant and wild type. The cell shape and arrangement of parenchyma cells in bc16mutant became irregular and disordered. Moreover, the parenchyma cell walls and the secondary cell walls of sclerenchyma cells in bc16 mutant under the epidermis layer were thinner than those in wild type. The results of genetic analysis revealed that the mutant trait was controlled by a single recessive gene, which was mapped in a 66.6kb region between InDel (insertiondeletion) markers 2F and 2H on chromosome 2 with 7 candidate genes. Among these genes, Os02g0738900, which is allelic to BC3 gene, was specially focused on. There was a T to A substitution at the very end of the 13th intron of Os02g0738900 which was at the 5113th base location from initiation codon by sequencing, which led an splicing forward mutation in the process of transcription, and six nucleotides were cut into mRNA as a result, which finally cause the stop of translation. Additionally, in the mutant, there were significant decrease in the expression of bc16 gene in roots, culms and leaves by realtime PCR method. The bc16 might affect the synthesis of sclerenchyma secondary cell wall and parenchyma primary cells wall, which could affect the mechanical strength of rice stem.

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Identification of Differentially Expressed Proteins in Roots of Rice（Oryza sativa） Infected with Rice grassy stunt virus DING Xinlun， XIE Liyan， ZHANG Jie， WU Zujian* 2016, 30(4): 356-362.  DOI: 10.16819/j.1001-7216.2016.5193 Abstract ( )   HTML ( )   PDF (1883KB) ( )   In order to find the proteins related to root maldevelopment caused by Rice grassy stunt virus(RGSV), elucidate the mechanism of root maldevelopment and better understand the molecular basis of interaction between RGSV and host rice, 2DDIGE coupled with MALDITOFMS was used to screen and identify differentially expressed proteins between RGSVinfected and RGSVuninfected rice roots. The acquired proteins were further analyzed using GoMiner programs and KEGG pathway database. The results showed that 56 protein spots (differential ratio>2) were differentially expressed, including 34 upregulated and 22 downregulated protein spots. Among them, 27 differentially expressed protein spots which belonged to 25 proteins were identified, and these proteins were mainly involved in 14 biological processes, 10 molecular functions and 12 KEGG pathways.

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Identification of qRL4, a Major Quantitative Trait Locus Associated with Rice Root Length XU Xiaoming1,2,3,#, ZHANG Yingxin1,3,#,WANG Huimin1,4, REN Cui5,WANG Ruci1,3, SHEN Xihong1,3,ZHAN Xiaodeng1,3,WU Weixun1,3,CHENG Shihua1,3,,CAO Liyong1,3, 2016, 30(4): 363-370.  DOI: 10.16819/j.1001-7216.2016.5071 Abstract ( )   HTML ( )   PDF (1061KB) ( )   To identify the qRL4, rice  lines derived from the hybrid rice Xieyou 9308 with genetic backgroud of Zhonghui 9308 (R9308) and substituted segements from Xieqingzao B (XB) were  agarcultivated  for phenotyping of rice seedling root length and molecular markerbased genotyping. The qRL4 was finally narrowed to a 624.6 kb interval (RM5687-InDel49) on chromosome 4. The identification of qRL4 will be helpful to clarify  genetic factors controlling root architecture in rice.

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Effects of Elevated Atmospheric CO2 and Temperature on Seed Vigor of Rice under Openair Field Conditions GAO Houyu1, JING Liquan2, CHEN Long1, JU Jing1, WANG Yunxia1, *, ZHU Jianguo3, YANG Lianxin2, WANG Yulong2 2016, 30(4): 371-379.  DOI: 10.16819/j.1001-7216.2016.5194 Abstract ( )   HTML ( )   PDF (862KB) ( )   The increases in atmospheric carbon dioxide concentration and air temperature are two important features of global climate change.The present study was conducted to reveal how rice seed vigor will be affected by these two important environmental factors when rice plants were grown under future environment conditions. By using the rice Free Air CO2 Enrichment(FACE) system, an inbred japonica rice Wuyunjing 23 was grown under four different combinations of CO2 concentration and temperature treatments, i.e. ambient air(Ambient), elevated \[CO2\](EC,Ambient+200 μmol/mol, elevated temperature（ET,Ambient+2℃） and elevated \[CO2\]+elevated temperature(EC+ET). At maturity, seeds were harvested and subjected to the standard germination trial in laboratory. The results indicated that compared with seeds obtained from ambient air, the seeds from EC plants showed higher value (+165%) in the electrical conductivity of deionized water in which seeds have been soaked for 24 hours. However, EC decreased the sprouting rate, germination rate, germination potential and germination index by 7.8%, 10.0%, 17.4%and 8.9%, respectively.The effects of ET and EC+ET on the above parameters followed the similar patterns, but in most cases the effects became smaller and were statistically insignificant. Compared with the ambient temperature, high temperature during growth reduced high CO2effects on the electrical conductivities of seed soaking solution, sprouting rate, germination rate, germination potential and germination index, which was shown by certain degree of interaction between CO2 concentration and temperature. The characteristics of sprout and root of the germinated seed were not changed by CO2 concentration or/and temperature increases during plant growth. The above results indicated that the sprouting rate, germination rate, germination potential and germination index of the seed of inbred japonica rice Wuyunjing 23 were significantly decreased when the seeds were produced in the high CO2 concentration environment. But such negative effects of high CO2 concentration on seed germination capacity of rice might be ameliorated by simultaneously moderate increase of air temperature during plant growth.

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Changes  in Cadmium Concentration in Rice Plants Under Different Cadmium Levels and Expression Analysis of Genes Retated to Cadmium Regulation ZHOU Quan, WANG Hong, ZHANG Yingxin, DONG Qing, MENG Shuai, CAO Liyong, SHAO Guosheng*, SHEN Xihong* 2016, 30(4): 380-388.  DOI: 10.16819/j.1001-7216.2016.6031 Abstract ( )   HTML ( )   PDF (4492KB) ( )   Using six indica and six japonica cultivars, differed in cadmium concentrations in the aboveground parts, the growth, heavy metal contents and expression levels of heavy metal transporter related genes were studied in a hydroponic experiment at six cadmium levels. Cadmium stress reduced plant height, shoot dry weight and chlorophyll content in rice leaves, inhibiting rice growth. Significant difference in cadmium content in rice roots and shoots among rice cultivars were found under different cadmium treatments, and the results showed that roottoshoot translocation may be a key process that determine the difference in cadmium contents between rice cultivars and subspecies, while cadmium absorption by roots had little effect. At various cadmium levels (from 0.50 to 2.00 mg/kg), saturation of cadmium accumulation in rice shoots were found in some cultivars that cadmium content stopped increasing or even decreased. Besides, the expression levels of OsNRMAP1，OsIRT2 and OsNAS2 were significantly increased at such cadmium treatment, which might be attributed to the regulation of rice plants.

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Effects of ControlledRelease Fertilizer Application on Double Cropping Rice Yield and Nitrogen Use Efficiency HOU Hongqian1,2,3， HUANG Yonglan4， JI Jianhua1,2,3， LIU Yiren1,2,3， LIU Xiumei1,2,3,*， HU Zhaoping5,6 2016, 30(4): 389-396.  DOI: 10.16819/j.1001-7216.2016.5163 Abstract ( )   HTML ( )   PDF (454KB) ( )   In order to study the effects of  controlledrelease fertilizer application on double cropping rice, a successive 2year locationfixed field experiment was carried out in double cropping region in red soil paddy field derived from the Quaternary red clay in Nanchang, Jiangxi Province of southern China. The field experiment covered 4 treatments including no fertilizer (CK),  recommended application split by three times (OF),  controlled release fertilizer all used as basal fertilizer (100CRF) and 80% controlled release fertilizer all used as basal fertilizer (80CRF), and each treatment had three replicates. During the two years plantation, rice yield, rice nitrogen uptake and nitrogen use efficiency of each treatment were measured  and the conclusion could be drawn that the average yield for the two years followed the order of 80CRF>100CRF>OF>CF>CK, and the treatment 80CRF, 100CRF, and OF increased rice yield by 25.32%, 2393% and 23.86% respectively, compared with CK (P< 0.05). However there was no significant difference between different nitrogen fertilizer treatments. As for the average nitrogen uptake in two years , 100CRF and 80CRF treatment were significantly higher than OF treatment in early rice and 100CRF treatment was higher than OF treatment in late rice (P < 0.05), but 80CRF and OF were no significant difference in late rice. The nitrogen uptake manifested same trend between straw and grain. The nitrogen recovery efficiency of 100CRF, 80CRF treatment were significantly higher than the OF treatment (P< 0.05). Nitrogen agronomic efficiency, partial factor productivity of applied N at the highest of 80 CRF, is significantly higher than 100CRF and OF treatments (P < 0.05). Nitrogen physiological efficiency and Soil N dependent rate at the highest of 80 CRF in late rice in 2012 and OF in doublerice in 2013 respectively, were significantly higher than 100CRF treatment (P < 0.05), but there was no significant difference between 80CRF and OF treatment. Therefore, onetime use of controlled release fertilizer regardless of the quantity and reduce the dosage of 20%, it could reach the recommended fertilization production levels, and could significantly increase the nitrogen content and uptake in rice. Full amount of controlled release fertilizer utilization rate of nitrogen fertilizer could only improve nitrogen uptake both early rice and late rice, but caused N luxury absorption and nitrogen physiological efficiency lower; Reduced by 20% controlled release fertilizer, the nitrogen recovery efficiency, the agronomic efficiency, and the partial factor productivity for applied N were significantly improved in early and late rice. There was no difference in nitrogen physiological efficiency between 80 CRF treatment and optimized fertilization. On the basis of stable yield, 80CRF treatment has saved the cost and improved the effect of the nitrogen utilization.

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Roles of Transcription Factor Gene OsPHR3 on the Utilization of Phosphate in Rice ZHANG Liang, SUN Wenxian, SUN Yafei, PEI Wenxia, LUO Wenzhen, SUN Rui, ZHANG Zhantian, XU Guohua, SUN Shubin* 2016, 30(4): 397-405.  DOI: 10.16819/j.1001-7216.2016.6011 Abstract ( )   HTML ( )   PDF (1595KB) ( )   Phosphorus, an essential macronutrient element for plant growth and development, is broadly participating in various plant life activities. However, low availability of soil phosphate is a major constraint for crop production in many agricultural systems. OsPHR3（LOC_Os02g04640）is a homolog of OsPHR2, the central regulator of Pisignaling in rice. Both OsPHR2and OsPHR3 belong to the MYBCC family members and have functional redundancy in part. In this study, OsPHR3 knockout and overexpression transgenic plants were obtained. The hydroponic culture, 32Pi isotopic and pot experiments were used to demonstrate the role of OsPHR3 in rice phosphate untilization. First, hydroponic experiments showed that overexpression of OsPHR3increased the phosphorus content of the rice, although the knockout lines had no significant difference with wild type plants. Second, 32Pi isotopic experiments revealed that overexpression of the gene promoted the absorption and distribution of phosphate, while the absorption rate in knockout lines decreased in comparison with wild type plants under Pideficient condition. Third, pot experiments demonstrated that overexpression of OsPHR3 enhanced the effective tillers and phosphorus content in seed. However, the panicle length in knockout lines is shorter than in wild type plants. In conclusion, OsPHR3 is a potential transcription factor for improving P efficiency in rice through molecular breeding.

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Roles of Two Genes Involved in  Histidine Biosynthetic Pathway in YeastLike Symbiont in Development of Nilaparvata lugens (Stl) TANG Yaohua1,2, WAN Pinjun2, HAO Peiying1, FU Qiang2, *, YU Xiaoping1, * 2016, 30(4): 406-416.  DOI: 10.16819/j.1001-7216.2016.6026 Abstract ( )   HTML ( )   PDF (2881KB) ( )   Nilaparvata lugens is a serious phloemfeeding pest of rice in China.  Based on genome and transcriptome data of N.lugens and yeastlike symbiont (YLS, also named Entomomyces delphacidicola str. NLU), the major biosynthesis pathways for amino acids in N.lugens were constructed.  In this study, we cloned two genes, EdeHis2 and EdeHis6, which catalyze critical steps in histidine biosynthesis pathway, and revealed the negative effects of doublestranded RNA (dsRNA) on the growth, development and survival rate of N.lugens. Homology searches and phylogenetic analysis showed that EdeHis2 and EdeHis6  origin from YLS genome, share high similarities with that of Metarhizium acridum and formed a clad in the phylogenetic tree, whereas no His2  or His6like genes was found in N.lugens genome. Temporal expression profiles of EdeHis2 and EdeHis6 showed that both genes were ubiquitously but unevenly expressed among the different life stages, and the spatial expression pattern showed they have higher expression levels in the fat body rather than head, leg, integument and midgut. Furthermore, no target products were amplified in head and wing genomic DNA of N.  lugens, rather than that in abdomen genomic DNA. At two, four and six days after dsEdeHis2 or dsEdeHis6 injection, the mRNA abundance of target genes was decreased by 45%-60% (EdeHis2)or 27%-55% (EdeHis6), comparing with blank control.Downregulation of EdeHis2 or dsEdeHis6 slightly increased the mortality by 8.3% or 9.2%, and delayed the nymphal duration of male and female by 0.43 and 065 day and 0.33 and 0.36 day, respectively. Moreover, both male (11%) and female adult (13%) showed wing deformation after injection of dsEdeHis6, higher than that in the blank control. In conclusion, EdeHis2 and EdeHis6 that origin from YLS were involved in histidine biosynthesis pathway, contributed to the survivor, development and wing formation of N. lugens.

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Response of Rice to Future Climate Change Based on Adaptive Adjustment in Southern Henan Province MA Rui1, JIANG Min1,2, *, XUE Changying2, SUN Bin1, ZHOU Tongyu1 2016, 30(4): 417-430.  DOI: 10.16819/j.1001-7216.2016.5189 Abstract ( )   HTML ( )   PDF (1462KB) ( )   In this paper, we have chosen nine sample sites in Xinyang City,He′nan Province and conducted evaluation studies on the influence of climate changes based on single cropping rice with three representative varieties, including early middle and late mature. According to the Intergovernmental Panel on Climate Change(IPCC) Special Report on Emission Scenarios(SRES) A2 and B2 scenarios, combining with Regional Climate Model(RCM), we have calculated and collected the daily meteorological data during  BASE period (1961-1990) and further period (2021-2025) at the nine sample sites.  Considering the direct gain effects of CO2 in the future, we have simulated and analyzed the possible impacts of the future climate changes on the rice yields by using ORYZAV3 model. On this basis, the adaptable adjustment schemes of rice yields in the different scenarios in the future are simulated.  Rice yields, its stability and changes of total production in the southern Henan region are finally obtained after adaptable adjustments. As the result shows, if the adaptable adjustment or the consideration of the direct gain effects of CO2 in the future climate change is not taken, the simulated rice yields will decrease by 14.1% in A2 scenario and 8.6% in B2 scenario in this region. With the varieties and sowing time adjusted and fertilizer efficiency of CO2 under consideration, the yields will increase by 17.2% in A2 scenario and 15.7% in B2 scenario. Besides, the total production under the two scenarios increases respectively by 148% and 13.2% more than the stage of BASE in this region. So it will be more scientific and optimistic in the assessment research of the future climate change scenarios if we take into account the adaptable adjustment.

Reviews and Special Topics

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Responses of Heat Dissipation in Rice to Stress ZHAO Xia1,2,#,YANG Huawei1,#,LIU Ranfang1, CHEN Tingting2, FENG Baohua2, ZHANG Caixia2, YANG Xueqin2, TAO Longxing2,* 2016, 30(4): 431-440.  DOI: 10.16819/j.1001-7216.2016.6003 Abstract ( )   HTML ( )   PDF (831KB) ( )   Nonphotochemistry quenching (NPQ) has been used to estimate the level of heat dissipation,which is originally transformed from light energy. Heat dissipation plays a key role in maintaining the balance of light energy transformation, and it is the main mechanism of rice leaf to deal with excessive light energy. Numbers of previous studies have demonstrated that the induced process of heat dissipation is regulated by ΔpH across thylakoid membrane, xanthophyll cycle and PsbS protein, etc. The relationship between NPQ and photoprotection is not linear.NPQ only acts as an effective indicator of photoprotection in some specified situation. Heat dissipation is closely related with the stress resistance of rice in that NPQ level in rice leaf increases under stress conditions of heat, chilling, nitrogen deficiency and drought. This paper reviews the recent progress of heat dissipation, and mainly by summarizing the induction and regulation procedure of heat dissipation, the relationship of NPQ and photoprotection and the response of NPQ to environmental factors, such as temperature, nitrogen nutrition,water and salt. The research prospects on the relationship of NPQ and photoprotection of rice is also discussed.

Short Communications

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Transgenosis of the Phosphomannomutase Transgene Increases Vitamin C Content in Rice GAO Lifen1, 2, XIA Zhihui2, 3, ZHANG Ji1, WANG Daowen2, ZHAI Wenxue2,* 2016, 30(4): 441-446.  DOI: 10.16819/j.1001-7216.2016.5129 Abstract ( )   HTML ( )   PDF (1041KB) ( )   VC (vitamin C) is an essential nutrient to human health. Due to lack of Lgulonolactone oxidase, the last enzyme involved in VC synthesis pathway, human could not synthesize VC by themselves. Rice is an important food crop and its nutritional value could be greatly improved by increasing the VC content in rice seeds. Phosphomannomutase (PMM) is an important enzyme in VC synthesis pathway, catalyzing the interconversion from mannose 6phosphate from mannose 1phosphate. In this study, Oryza PMM gene (OsPMM) that was under the control of seedspecific expressed promoter Bx14 was transferred into ‘C418’, a restorer line of threeline japonica hybrid rice, using the double rightborder vector pMNDRBBin6 through an Agrobacterium tumefaciensmediated system. Molecular analysis revealed that OsPMM was integrated into the genome of transgenic ‘C418’, and the homozygous and markerfree transgenic line was obtained in the T2 generation. Gene expression analysis of transgenic lines showed the expression level of OsPMM was significantly increased in seeds, and accordingly, the VC content in the seeds of transgenic plant also increased by 25-50%.